CAM CLUTCH Product Catalog
OVERRUNNING • INDEXING • BACKSTOPPING
www.ustsubaki.com
Tsubaki Cam Clutch Solutions
Bearing Cam Spring
Over the last 50 years, Tsubaki engineers have spent thousands of man hours designing and improving uni-directional/mechanical clutches in an effort to improve reliability and performance. Evolution of the uni-directional clutch started with simple prop and ratchet type designs, and has progressed to the roller ramp and non-contact sensing cam type commonly used today. Innovative designs and features incorporated into our cam clutch products assure efficient and dependable operation in the harshest environments.
Inner Race Outer Race
Ratchet Design Ratchet Clutch
Roller Ramp Design Roller Clutch
Tsubaki Sprag Design Tsubaki Cam Clutch
Typical Applications
Air Cleaning Plants Agricultural Machines Bucket Elevators Compressors Conveyors Cranes and Hoists Dry Cleaning Machinery Duplicator Equipment
Heat-treatment Furnaces Induced Draft Fans Multi-state Conveyors Packaging Machinery Printing Machinery Pumps Punch Presses and Feeders Power Plants
Refinery Equipment Speed Reducers Standby Power Units Textile Looms Two-speed Grinders Fish Net Machines Washing Machines Wire Winding Machines
TABLE OF CONTENTS
Cam Clutch Product Overview
2 4
Cam Clutch Basics
BR Non-Contact Innovation Backstop Clutch Selection Guide Indexing Clutch Selection Guide Overrunning Clutch Selection Guide
11 12 18 23 32 36 38 42 44 46 48 50 52 56 60 67 74 78 80 82 85 86 88 90 92 92
MGUS Series Cam Clutch MGUS-R Series Cam Clutch BB Series Cam Clutch TSS Series Cam Clutch TFS Series Cam Clutch BUS200 Series Cam Clutch PBUS Series Cam Clutch MZ Series Cam Clutch OB Series Cam Clutch MIUS Series Cam Clutch MZEU Series Cam Clutch BREU Series Cam Clutch BR-HT Series Cam Clutch BRUS Series Cam Clutch BSEU Series Cam Clutch
BS Series (BS30 to BS75) Cam Clutch
BS Series Torque Arm
BS-F Series (BS85F to BS465F) BS/BS-F Series Safety Cover
CA Series
Engineering Section Interchange Chart
Overrunning Application Request Form Backstop Application Request Form
110 111
www.ustsubaki.com
TSUBAKI BACKSTOP CAM CLUTCH PRODUCTS TSUBAKI CAM CLUTCH
TSUBAKI INDEXING,
P. 82
P. 80
P. 90
P. 56
MIUS MIUS Series is for mid-speed indexing applications up to 300 cycles a minute. Bore Range: 0.500" to 6.250" (12.7 to 160 mm) Torque Range: 280 to 27,290 lbs. ft. COMPETITOR MODELS: Formsprag HPI Morse MI Marland RMS
P. 86
CA CA line of backstops are an integral part of the reducer. The unique non-rollover cam design is key and prevents damage to the gears, shafts and drive train. This is a drop- in replacement for Dodge ® reducers. Bore Range: 0.738" to 1.750" (18.75 to 44.45 mm)
BS & BS-F BS Series is designed for lower speed conveyor applications. The unique non-rollover cam design provides higher torque capacity, assuring full engagement. Bore Range: 0.750" to 5.315" (20 to 135 mm) Torque Range: 217 to 11,580 lbs. ft. BS-F Series is designed for simple, drop-in installations to all major competitive backstop products. Uses unique seal design for maximum life, minimal maintenance. Bore Range: 2.360" to 18.310" (60 to 465 mm) Torque Range: 4,980 to 722,000 lbs. ft.
BSEU BSEU Cam Clutches are a European variation popular on many bucket elevators in North and South America. Bore Range: 0.787" to 3.543" (20 to 90 mm) Torque Range: 159 to 3,467 lbs. ft. COMPETITOR MODELS: Formsprag RSBW
Torque Range: 45 to 901 lbs. ft. COMPETITOR MODELS: Dodge 24 Series
Morse CR/BW Stieber RSBW
P. 42
P. 78
P. 74
P. 67
TSS TSS Series clutch is designed for press fit installation. Outside dimensions are the same as series 62 ball bearings. Bore Range:
BR-HT BR-HT Series is designed for backstop applications where high-speed overrunning is required. Lift off cam design assures minimal heat generation and longest life. Bore Range: 0.787" to 5.118" (20 to 320 mm) Torque Range: 77 to 269,950 lbs. ft. COMPETITOR MODELS: Formsprag RSCI; Ringspann FXM
BREU BREU Series is designed for backstop applications where bearing support and modular construction is desirable. Bore Range: 1.181" to 5.906" (30 to 150 mm) Torque Range: 447 to 25,009 lbs. ft. COMPETITOR MODELS: Formsprag RIZ; Stieber RIZ
BRUS BRUS series of high-speed external backstops utilize non- rollover and lift-off design cams. This is a drop-in replacement for Falk ® BIF backstops. Bore Range: 1.125" to 3.750" (28.58 to 95.25 mm) Torque Range: 700 to 4,420 lbs. ft.
0.314" to 2.362" (8 mm to 60 mm) Torque Range:
4 to 479 lb.ft. (6 to 649 Nm) COMPETITOR MODELS: Formsprag AS Morse NSS Ringspann FCN
COMPETITOR MODELS: Falk BIF; Formsprag FHB; Ringspann FRXF
Dodge ® is a registred trademark of Baldor Electric Company Corporation. Falk ® is a registered trademark of Rexnord Industries, LLC. 2
PRODUCT OVERVIEW
OVERRUNNING AND GENERAL CAM CLUTCH PRODUCTS
P. 32
P. 60
P. 50
P. 38
MGUS/MGUS-R MGUS Series is suitable for applications which require low to high speed inner race. MGUS-R Series contains a built-in oil reservoir and can be used for backstopping
MZEU MZEU Series is designed for overruning applications. These units come pre-lubricated, and can be adapted with flanges and torque arms to suit a wide variety of applications. Bore Range: 0.472" to 5.906" (12 to 150 mm) Torque Range: 44 to 24,930 lbs. ft. COMPETITOR MODELS: Formsprag GFR/GFRN Stieber GFR
MZ MZ Series is designed for low speed indexing applications that require inner or outer race overrunning. These units come pre-lubricated for easy installation and long service life. Bore Range: 0.591" to 2.756" (15 to 70 mm) Torque Range: 137 to 2,242 lb.ft..
BB BB Series Cam Clutch has the bearing dimensions and
characteristics of a 62 Series type ball bearing. This design provides easy installation and is ideal for general overrunning applications Bore Range: 0.590" to 1.575" (15 to 40 mm)
applications. Bore Range:
Torque Range: 21 to 192 lb.ft.. (29 to 260 Nm) COMPETITOR MODELS: Formsprag CSK; Morse KK; Ringspann ZZ; Stieber KK
0.500" to 6.250" (12.7 to 160 mm) Torque Range:
280 to 27,290 lb.ft. (380 to 37,000 Nm) COMPETITOR MODELS: Formsprag FSO; Morse MG; Ringspann FB
(186 Nm-m to 3,040 Nm) COMPETITOR MODELS: Stieber SMZ
P. 52
P. 46
P. 44
P. 48
TFS TFS Series has two vertical keyways on the outer race to assist with positioning. Outside dimensions are the same as series 63 ball bearings. Ideal for general overrunning applications. Bore Range: 0.472" to 3.150" (12 to 80 mm) Torque Range: 13 to 2,894 lbs. ft. Competitor Models: Formsprag ASNU; Morse NFS; Ringspann FC/FDN
PBUS PBUS Series clutch is packed with a special grease for general applications. The outer race has provision for mounting gears, pulleys, and sprockets. Bore Range: 0 .375" to 1.750" (10 to 45 mm) Torque Range: 41 to 1,623 lb.ft. (56 to 2,200 Nm) COMPETITOR MODELS: Formsprag FSR; Morse PB-A; Renold SB
BUS200 BUS Series is specifically designed for shaft mounting applications that require high speed inner race overunnning or low to mid speed outer race 0.650" to 3.122" (16.5 to 79.3 mm) Torque Range: 39 to 1,025 lbs. ft. Competitor Models: Formsprag FS50; Morse B200; Renold SD overrunning. Bore Range:
OB-ON/OF & OB-SF OB-ON/OF Series is an enclosed unit housing cam clutch units and a common shaft. These units are used for high speed overrunning applications. Torque Range: 2,318 to 59,270 lbs. ft. OB-SF Series is an enclosed unit housing cam clutch units that allow for continuous high speed overrunning and engagement and high torque capacities. Torque Range: 231 to 4,337 lbs. ft.
www. ustsubaki .com
3
Typical Cam Clutch Applications
Air cleaning plants Agricultural machines Bucket elevators Compressors Conveyors Cranes and hoists Dry cleaning machinery
Duplicator equipment Fish net machines Heat-treatment furnaces Induced draft fans Multi-state conveyors Packaging machinery
Printing machinery Pumps Punch presses and feeders Power plants Refinery equipment Speed reducers
Standby power units Textile looms Two-speed grinders Two-speed shiftovers Washing machines Wire winding machinery
CAM CLUTCH BASICS Tsubaki Cam Clutch products are designed to transmit torque in one direction of rotation, and overrun (freewheel) in the opposite direction of rotation. All Tsubaki Cam Clutch products utilize the same principles of operation. Tsubaki offers various series of products to address the many types of applications where Cam Clutch products are most often used. The three most common types of applications are listed below.
1. Backstopping In backstop applications, the clutches are used to prevent reverse rotation of drive shafts, which may cause damage to machinery and other expensive equipment. With the outer race of the clutch anchored stationary, the inner race can overrun freely in one direction of rotation. Reverse rotation is instantaneously prevented by the automatic engagement of the clutch. Typical backstop applications are in conveyor systems and gear reducers. Please reference Figure 1 for an example of a typical backstopping application.
Figure 1: General backstopping application example
Backstopping Application & Selection begins on page 12.
Application
Characteristics Less than 150 r/min. 150 to 700 r/min. 700 to 3,600 r/min.
Cam Clutch Model Options
Low speed overrun
BS, BS-F, BS-R, BSEU, BUS200, MZEU, MZ, MGUS, MGUS-R, TFS, TSS, BB BREU, BR-T, BUS200, MZEU, MZ, MGUS, MGUS-R, TFS, TSS, BB
Medium speed overrun High speed overrun
BREU, BR-HT, BRUS, MGUS-R, MZEU, MZ, TFS, TSS, BB
4
2. Indexing In this mode of operation, reciprocating motion applied to the driving race of the clutch is transformed into uni-directional intermittent motion at the driven race. For example, on a feeding roller, the clutch is mounted on the roller and a torque arm is connected to the driving race of the clutch. A crank motion mechanism provides reciprocating motion to the driving race. The clutch drives in the forward stroke (index) and overruns on the return stroke, resulting in intermittent uni-directional motion of the feeding roller. Please reference Figure 2 for an example of a typical indexing application. CAM CLUTCH BASICS
Figure 2: General indexing application example
Indexing Application & Selection begins on page 18.
Application
Characteristics*
Cam Clutch Model Options
High speed, Small feed angle
FREQUENCY: More than 300 cycles/min. FEED ANGLE: Less than 90° FREQUENCY: Less than 300 cycles/min. FEED ANGLE: More than 90° FREQUENCY: Less than 150 cycles/min. FEED ANGLE: More than 90° FREQUENCY: Less than 300 cycles/min. FEED ANGLE: More than 90° FREQUENCY: Less than 300 cycles/min. FEED ANGLE Less than 90°
Contact Tsubaki
Low-medium speed, Small feed angle
MIUS, PBUS, MZEU, MZ, TFS, TSS, BB
Contact Tsubaki
Low speed, Large feed angle
Backstop device for indexing
MIUS, PBUS, MZEU, MZ, TFS, TSS, BB
Infinite variable feed
MIUS, PBUS, MZEU, MZ, TFS, TSS, BB
* FEED ANGLE is the degree of rotating that the Cam Clutch must accommodate while indexing. See page 18 for more details.
Cam Behavior and Cam Clutch Operation In indexing applications, reciprocal movement of a certain angle (0 ) is provided at the outer race of the Cam Clutch to perform engagement and overrunning in turn continuously and obtain intermittent rotation. In the case of the Cam Clutch shown in the figure to the right, when the outer race moves from A to B, the Cam Clutch engages to rotate the inner race (of the driven side) by angle 0 , i.e., from a to b. However, the Cam Clutch does not operate to stop the inner race at position b. When the outer race rotates in reverse from B to A, the Cam Clutch overruns while the inner race (of the driven side) does not rotate. By repeating this sequential movement, the inner race (of the driven side) rotates intermittently within the preset angle (0 ).
Reciprocal movement of the outer race Intermittent movement of the outer race
θ
B
A
b
a
www. ustsubaki .com
5
CAM CLUTCH BASICS 3. Overrunning Clutches used in this type of application overrun at either the inner or outer race during the majority of the clutch operating time, and are occasionally called upon to lock up and drive. A typical application is a two-speed drive, where an electric motor and a geared motor are connected to a single driven shaft through one-way clutches. The machine can be driven by either the electric motor or geared motor. When the geared motor drives at low speed, the clutch engages. When the faster turning electric motor drives the machine, the clutch overruns. The clutch automatically switches between low speed and high speed. Please reference Figure 3 for an example of a typical overrunning application.
Figure 3: General Overrunning application example
Overrunning Application & Selection begins on page 23.
Application
Characteristics
Cam Clutch Model Options
High speed overrun, High speed engagement High speed overrun, Low to medium speed engagement High speed overrun, Low speed engagement
OVERRUNNING: 700 r/min and up ENGAGEMENT: 700 r/min and up OVERRUNNING: 700 r/min and up ENGAGEMENT: Up to 700 r/min OVERRUNNING: 700 r/min and up ENGAGEMENT: Up to 200 r/min OVERRUNNING: Up to 700 r/min ENGAGEMENT: Up to 700 r/min
MZEU, MZ, OB-series
Dual drive and two speed drive
MZEU, MZ, OB-series
MZEU, MZ, BREU, BR-HT, OB-series
Low to medium speed overrun, Low speed engagement
BB, PBUS, MGUS, MZEU, TFS, TSS, BUS200, MZ BB, PBUS, MGUS, MIUS, MZEU, TFS, TSS, BUS200, MZ
Overrunning when rotating speed of driven side becomes faster than the driving side
Free wheeling
Continuous overrunning, manual engagement Engage in one direction, Overrun in reverse direction
Manual drive
BB, PBUS, MZ, MIUS, MZEU, TFS, TSS, BUS200
Normal engagement and reverse overrunning
BB, PBUS, MGUS, MIUS, MZEU, TFS, TSS, BUS200
6
CAM CLUTCH BASICS
4. Basic Cam Clutch Construction Figure 4 provides a sectional view of the components which reside inside of a Tsubaki MZ Series Cam Clutch. This illustration is typical of Tsubaki Cam Clutch construction. Each of the components identified are critical for function and performance of the assembly.
Bearing Cam Spring
Inner race Outer race
Figure 4: Cam Clutch major component parts
Part
Appearance
Function
A number of cams set regularly in between the inner and outer races function as props or sliders depending on the relative rotating directions of the inner and outer races. This action causes engagement (clutching) and disengagement (overrunning) of the clutch inner and outer races. The cams are the vital component of a Cam Clutch, and they are available in various models and types to suit a variety of applications.
Cam
Inner Race
The inner and outer surface of the races are hardened and precision ground to enable the ability to withstand high compression stress during cam engagement.
Outer Race
Compressed springs are set at both ends of the cams to ensure that all of the cams contact the inner and outer races at all times. Thus, the cams are always ready for immediate engagement. This is extremely important so as to ensure that the load is spread evenly across all cams when they engage with the inner and outer races.
Spring
The bearings maintain concentricity of the inner and outer races and bear the radial load for the engagement of the cams and the inner and outer races. Maintaining concentricity is particularly important to ensure that the load is spread equally and simultaneously over the cams at the time of engagement.
Bearing
www. ustsubaki .com
7
CAM CLUTCH BASICS
All Tsubaki Cam Clutches use a cam type construction. This is also referred to as a “sprag” style clutch. An older style clutch which Tsubaki does not supply is called a “Ramp & Roller” or simply a "Roller" clutch. The following is an explanation of the features of each type. This discussion mentions Tsubaki BS Series backstop clutches but is relevant to other Tsubaki Cam Clutches.
Non-rollover Backstop Cam
General Cam Construction
Cams and their constructions The BS Series Cam Clutches use non-rollover cams which provide an additional level of safety. Even if a Cam Clutch has been selected appropriately for an application, unanticipated loads can occur. With a traditional cam profile, as used by some manufacturers, the unanticipated load might cause the cam to “rollover,” allowing the conveyor to move backward. The cam profile used by Tsubaki is most suited for the backstopping function, placing importance on the load distribution among multiple cams and a large surface cross section. Even if an unexpectedly large reverse torque occurs, the clutches will not roll over, preventing the conveyor from reversing.
Roller
Outer race
BS and BS-F Series Cam Clutches use a structure utilizing cams and rollers alternately arranged for higher overrunning speeds and torque capacities.
Cam
Inner race
Spring
BS Series Cam Clutch construction and cam profile
Roller
Cam
Outer race
BS-F Series Cam Clutches employ a unique cam cage structure that supports the cams and rollers, which helps to further improve on the BS series’ torque capacities and over- running speeds. The cam cage de- sign also helps the BS-F to provide the narrowest available footprint for a backstop with an I-beam torque arm.
Inner race
Cage ring
Spring
BS-F Series Cam Clutch construction and Non-rollover cam design
8
CAM CLUTCH BASICS
OPERATING PRINCIPLES
1
O'
The outer race's rotation is stopped by the torque arm. Cams contact with the inner and outer races at points A and B respectively. AB maintains a constant engagement angle (strut angle º) with the center line O-O'. The strut angle is an integral part of the overrunning and engagement function of the BS Cam Clutch. See 1.
Outer race
A
Cam
Spring
B
Inner race
Strut angle(º)
O
Springs give the rotational moment of F to cams ensuring precise contact is maintained between the inner and outer races. When the inner race (conveyor shaft) rotates in the direction of the black arrow, the inner race overruns smoothly because AB does not act as a strut. At this time, cams maintain light contact due to the spring force. See 2.
2
F
F
Cam
Spring
3
O'
Outer race
A
When the conveyor stops and the inner race (conveyor shaft) rotates in the direction of the white arrow, the inner race is locked immediately by the cams because AB acts as a strut, and prevents the conveyor from rotating in reverse. See 3.
Spring
F
B
Strut angle(º)
Inner race
O
Overrunning
Engagement
Self-lubrication function When the inner race overruns, rollers also rotate so the cam and roller cage orbit around the outer circumference of the inner race at low speed. Grease in the cam and roller cage spreads completely throughout the insides of the Cam Clutch due to the orbital motion, thus maintaining good lubrication.
V 2
Roller
Cam
V 1
www. ustsubaki .com
9
CAM CLUTCH BASICS
DISPLACEMENT OF CONTACT POINT FUNCTION
Rollers function as bearings and orbit while rotating on their axis, and supporting the outer race. There is a slight clearance between the rollers, the inner and outer races; therefore the bottom of the cam space between the inner and outer races is slightly wider compared with the top. Cams always maintain contact by spring force, and the slant of the cams is automatically different at the top and the bottom. Cams continuously orbit by changing the contact point with the inner and outer races; therefore the wear on cams due to overrunning is diminished to the minimum, and the overrunning wear life on the Cam Clutch is at the maximum length.
BS/BS-F Series
Slightly narrow
Outer race
Inner race
Different inclination
Slightly wide
For the conveyor, which is always in an overrunning condition during the operation, as well as the self- lubrication function and the sliding speed diminishing function, it is one of the major features of a cam and roller cage to realize a long operating life. Tsubaki BS and BS-F Cam Clutch compared with Ramp & Roller Clutch Cam Clutch cams slide on the outer circumference of the inner race (Di) at the decelerated sliding speed due to the sliding speed diminishing function described above. The contact force of cams and inner and outer
races are given only by spring force (Ps). As for the Roller Clutches, rollers slide in the inner circumference of the outer race (Do) because rollers are built onto a roller cage which is connected with the inner race. Therefore the sliding speed of the Roller Clutch is faster when compared with that of the Cam Clutch between the cams and inner race. In addition, the contact force of rollers and the outer race is quite large in the Ramp & Roller design because the centrifugal force (Pc) caused by the rotation of the roller cage is added to the spring force (Ps). The BS Cam Clutches overrun with low sliding speed and low contact force, thus the BS Cam Clutches have a long overrunning wear life when compared with the Roller Clutches.
Cam Clutch
Roller Clutch
P s
P c
F
P s
V 2
D o
D i
10
BR-HT, BREU, BRUS SERIES INNOVATION
NON-CONTACT DESIGN EXTENDS SERVICE LIFE Greatly Increased Service Life
Outer Race
Made possible by Tsubaki’s extensive experience in mechanical power transmission, the cams used in the BR Cam Clutch offer a unique cross section that provides positive mechanical engagement only when needed. Otherwise, the Cam Clutch rotates freely with absolutely no mechanical contact in the clutch mechanism. The result is a greatly increased service life compared to conventional types.
Inner Race
Cam Cage
Backstop Applications with High-Speed Overrunning When the Cam Clutch is stationary, the cam locks the inner and outer races together (Figure 5) . When the inner race (load side) overruns at a high speed, the cam disengages by releasing the inner race (Figure 6) . When the inner race stops, the cam rotates back into an engaged position. If the inner race tries to rotate in the reverse direction, the cams then serve as a stop between the anchored outer race and inner race to prevent reverse rotation and provide backstopping. High-Speed and Low-Speed-Engaged Overrunning When the Cam Clutch is stationary, the cam locks the inner and outer races together (Figure 5) . When the inner race (load side) overruns at a high speed, the cam disengages by releasing from the inner race (Figure 6) . When the high-speed rotation of the inner race stops and the inner race begins to rotate slowly, the cam rotates back into an engaged position. Then when you start to drive the outer race at low speed of rotation, the cams serve as a prop and drive the inner race at the same low speed of rotation. Please reference Figure 7 . A More Economical Design The open-type BR Series features a simple design in which the Cam Clutch mechanism is incorporated in a cage between standard dimension inner and outer bearing races. This allows the Cam Clutch to be easily and economically integrated into a wide variety of mechanical systems. Tsubaki also offers a package- type Cam Clutch that incorporates a bearing assembly to reduce maintenance demands.
Figure 5: Entire Cam Clutch is stationary
Figure 6: Inner race only turning
Figure 7: Inner and outer race locked and turning
www. ustsubaki .com
11
Backstop Clutch Selection Guide
BACKSTOPPING TO PREVENT REVERSE ROTATION
A backstop Cam Clutch is used to prevent the rotating shaft from being driven in the reverse direction. The Cam Clutch will continue overrunning while the shaft rotates and engages to prevent reverse shaft rotation. Normally, the inner race is mounted on the rotating shaft, and the outer race is fixed to the machine frame. The inner race overruns in normal operation. As soon as the shaft begins to rotate in the reverse direction, the cams engage with the inner and outer races to prevent reversing. Figure 8 depicts a typical setup for installing a backstop Cam Clutch. Backstop Cam Clutch Speed Grouping Backstopping Cam Clutches are grouped into three different speed classifications that are dependant on the overrunning speed and load conditions. The following table provides the three different classifications for consideration.
Cam
Free run
Outer race Inner race Torque arm
Figure 8: Typical backstop installation
12
BACKSTOP CAM CLUTCH MOUNTING ORIENTATION
Preventing reverse rotation of inclined and vertical conveyor systems is one of the most common application solutions provided when implementing a backstop Cam Clutch. The following table identifies the three standard mounting types and the given series associated with each mounting type. Please reference Figure 9 for a depiction of the mounting styles.
Mounting Location Designator
Overrunning Speed (RPM) Reverse Torque
Mounting Position
Common Application
Typical Series
Backstopping for low speed overrunning
0 - 150 RPM High Reversing Torque
A
Pulley Shaft
BS/BS-F/BSEU
150 to 700 RPM Medium Reversing Torque
Intermediate Shaft - Gear Reduction Systems
Backstopping for medium speed overrunning
B
MGUS/MGUS-R
Backstopping for high speed overrunning
Directly connected to motor shaft
700 to 3,600 RPM Low Reversing Torque
C
BR-HT/BREU/BRUS
A, B, and C mounting types
Cam Clutch BS Series
A
B
Cam Clutch MGUS-R Series
Reducer Main Motor
C
Cam Clutch BR-HT Series
Figure 9: A,B,C backstop mounting
www. ustsubaki .com
13
Backstop Clutch Selection Guide
BACKSTOPPING FOR LOW SPEED OVERRUNNING (OVERRUNNING AT 150 RPM OR LESS)
In this application, the inner race is mounted directly onto the conveyor head pulley, or driven shaft. The outer race is connected to the conveyor frame to prevent reverse rotation. Since reverse rotation is prevented directly by the conveyor shaft without using a drive chain, gears, or couplings, this is regarded as the safest and most reliable mounting method. Furthermore, due to the fact that the Cam Clutch is connected to the conveyor pulley, low overrunning slip speed is reduced, as well as the slipping distance. The result is reduced wear and long service life. In addition to conveyor systems, this system is also used to prevent reverse rotation on inclined and screw type pumps. Please see Figure 10 for an illustration of mounting.
Typical Series
Advantages
• Designed specifically for conveyor applications • Dust-proof enclosure • Virtually maintenance-free
BS/BS-F/BSEU
Figure 10: BS Series mounting low speed
BACKSTOPPING FOR MEDIUM SPEED OVERRUNNING (150 TO 700 RPM) In this application, the Cam Clutch is mounted on a gear reducer shaft rotating at medium speeds to prevent reverse rotation. As speed increases, the torque required to maintain the load at a given rate decreases. Therefore, the Cam Clutch required only needs to withstand a comparatively small torque that is inversely proportional to the rotating speed ratio of the reducer output shaft. Considering the application requirements, even a small Cam Clutch can be utilized in this application. Figure 11 provides an illustration of how the Cam Clutch could be mounted for this particular application.
Typical Series
Advantages
Cam Clutch
• Compact design can handle high torque • Excellent wear characteristics
MGUS/MGUS-R
Reducer
Motor
Figure 11: MGUS Series mounting medium speed
14
BACKSTOPPING FOR HIGH SPEED OVERRUNNING (OVERRUNNING AT 700 TO 3,600 RPM)
Inclined Belt Conveyors In this application, the gear reducer is tasked with driving a large scale inclined conveyor system. The Cam Clutch is installed to prevent the conveyor from rolling backwards in the event of stoppage or overload. As depicted in Figure 12 , the Cam Clutch is mounted directly onto the reducer to prevent damage that would result due to reverse rotation.
Large Scale Inclined Belt Conveyors
Motor
Coupling
Main Shaft
Reduction Gearbox
Cam Clutch
Bearing Strand
Figure 12: Cam Clutch installed on gear reducer
Pump/Compressor Systems There are many applications in which multiple pump or compressor systems are feeding into the same line. These are common in applications where energy savings is required, or emergency backup/redundancy is highly desired. When the system is shut down, or another pump comes on line, there may be a tendency for a given pump to back-spin when not running. Allowing this to happen may result in damaging the pump or compressor. Installing a backstopping Cam Clutch can prevent this. Please reference Figure 13 for an illustration example.
Pump & Compressor Systems
Pump or Compressor
Cam Clutch
Coupling
Motor
Figure 13: Cam Clutch installed on pump/compressor system
www. ustsubaki .com
15
Backstop Clutch Selection Guide
INFORMATION FOR SELECTION
BACKSTOP SELECTION Backstop clutches by definition are required to hold back a load from moving in a reverse direction. Care must be taken in calculating the torque requirements and should be based on maximum or worst case conditions and not averages or normally seen loads. Because the failure of a backstop or holdback clutch might result in dam- ages, take time in considering all the possible loadings and select appropriate service factors. Below is more than one selection formula; it is generally advised to select the Cam Clutch that provides the largest safety factor.
General Selection Method: A) Calculate the static torque reverse motion based upon the maximum load expected and multiply it by the service factor. Selection is based on the formula to the right. B) Select the clutch by:
Required Torque x Service Factor = Design Torque
The torque capacity of the selected Cam Clutch must be greater than the design torque requirement, must accept the maximum overrunning speed, and be suitable for the bore and installation method required.
1) Design torque requirement 2) Maximum overrunning speed 3) Bore size and installation method
Motor Stall Torque Selection Method: Another method commonly used to select the proper backstop clutch size for conveyors is to use the motor name plate ratings plus the motor's ability to produce excess torque. Depending on the motor size, it may develop over 300% of rated torque. After stalling an overloaded conveyor can overload the backstop. For proper selection of the backstop, all facets of the mechanical system should be considered to ensure that the backstop is not the weakest link in the conveyor drive. If the motor breakdown torque is not known, refer to the motor manufacturer.
Selection is based on the following formula:
Motor power hp x 5250 Shaft speed N (r/min)
S < T max _
Motor stall torque T(lb.ft.) =
x
or
Motor power kW x 9550 x Shaft speed N (r/min)
< T max _
S
Motor stall torque T(N • m) =
S = Service Factor
T max = Torque capacity of the Cam Clutch and must be greater than the motor stall torque
Select service factor from table below: % of Normal motor rating
Service factor
175% 200% 250% 300%
1.30 1.30 1.67 2.00
NOTE Always allow for the maximum possible load in your calculations, since backstopping often occurs when the conveyor is loaded above its normal loading capacity.
16
Bucket Elevator Selection Method: The torque capacity of the selected Cam Clutch must be greater than the calculated torque (T), must accept the required shaft speed, and be suitable for the bore and installation method required.
Cam Clutch
Chain and sprocket
Torque arm
Bucket
Metric formula: T(Nm) =
Motor speed reducer
9.8 x (L + D) x Q x 1000
x Service Factor
120 x V
L = Total lift in meters D = Pitch diameter of head sprocket in meters Q = Maximum possible load in tons per hours (1 ton = 1000 kg)
V = Velocity of conveyor in meter/minute SF = Service Factor from Table on page 16
Belt Conveyor Selection Method: Using these calculations, a slightly smaller Cam Clutch might be suggested because friction factors inherent in the belt conveyor are taken into consideration. Any calculations from this formula should be compared with the Motor Stall Torque Selection Method. We strongly suggest that any Cam Clutch selection be based on the larger value and choose the Cam Clutch that provides a greater safety factor. Please contact Tsubaki with any questions.
Selection Procedure: (1) Calculate the power to move an empty belt and idlers: (P1)
BS Cam Clutch
Belt conveyor
ℓ + ℓ 0
P 1 = 0.06 x f x W x V x
(kW)
Torque arm
367
(2) Calculate the power to move a loaded belt horizontally: (P2)
Motor
Speed reducer
ℓ + ℓ 0
P 2 = f x Qt x
(kW)
367
Note: f = Friction coefficient of rollers (0.03 normally used) h = Total lift (m) ℓ = Horizontal distance between head pulley and tail pulley (m) ℓ 0 = Modification coefficient for ℓ (49 m normally used ) N = Shaft speed on which the clutch is mounted – r/min Q = Max. possible load in tons per hour (metric ton/hr.) SF= Service factor V = Velocity of conveyor (m/min) W = Weight of moving parts of the conveyor in the unloaded condition (kg/m) 400 450 500 600 750 900 Estimated Weight: W 22.4 28 30 35.5 53 63 Width of Belt (mm) 1050 1200 1400 1600 1800 2000 Estimated Weight: W 80 90 112 125 150 160 (W) Estimates for non-loaded belt weight (kg/m) Width of Belt (mm)
(3) Calculate the power to move the load vertically: (P3)
h x Qt
P 3 =
(kW)
367
(4) Calculate the backstop power: (Pr)
Pr = P 3 - 0.7(P 1 + P 2 ) (kW)
(5) Calculate the backstop torque: (T)
9550 x Pr
T =
x SF (N m)
N
(6) Select the proper clutch which satisfies the calculated backstop torque (T)
www. ustsubaki .com
17
Indexing Clutch Selection Guide
INDEXING (INTERMITTENT FEED) In this application, reciprocal movement of a certain angle ( 0
) is provided at the outer race of the Cam Clutch to alternately engage then overrun continuously so as to obtain intermittent rotation. In the case of the Cam Clutch shown in Figures 14, 15 , when the outer race moves from A to B, the Cam Clutch engages to rotate the inner race (of the driven side) by angle 0 , i.e., from a to b. However, the Cam Clutch does not operate to stop the inner race at position b. When the outer race rotates in reverse from B to A, the Cam Clutch overruns while the inner race (of the driven side) does not rotate. By repeating this sequential movement, the inner race (of the driven side) rotates intermittently within the preset angle ( 0 ). This angle of movement ( 0 ) is referred to as the "feed angle" that the Cam Clutch must accommodate.
Reciprocal movement of the outer race Intermittent movement of the outer race
θ
B
A
b
a
Figure 14: Typical indexing application example
Figure 15: Cam Clutch inner and outer race interaction
Advantages of indexing mechanisms that use Cam Clutches 1. Accurate feeding without backlash. 2. Feeding distance can be simply adjusted and is stepless. 3. The indexing mechanism has low running costs.
There are six different classifications of Indexing Cam Clutch applications. Application
Specification
Frequency (number of rotations) = 300 cycles/min. and above Feed angle ( 0 ): Up to 90° Frequency (number of rotations) = 300 cycles/min. or less Feed angle ( 0 ): Up to 90° Frequency (number of rotations) = 150 cycles/min. or less Feed angle ( 0 ): 90° and more
(1)
High speed and small feed angle
Medium and low speed and small feed angle
(2)
(3)
Low-speed and large feed angle
(4) Backstopping in intermittent feeding Frequency and feed angle are the same as those of Cam Clutches for feeding
Application method is the same as (2) except that material is stopped by force during feeding Application method is the same as (2) except that the rotating speed adjusts steplessly by changing the feed angle ( 0 ) during operation
(5)
Feeding with stopper
(6)
Speed change
18
(1) Indexing applications with:
HIGH
(2) Indexing applications with: MEDIUM AND LOW SPEED AND SMALL FEED ANGLE (Feed frequency: N = Up to 300 cycles/min.) (Feed angle: 0 = Up to 90°; N × 0 = 20,000 max.) Indexing in this application range is applicable to many machines. Figure 17 shows an example of a paper feeding section on an automatic stapler. The reciprocating movement of the eccentric disk is converted by the Cam Clutch into an intermittent feed motion, which drives the belt conveyor. Hence, stapling is timed to the intermittent feeding motion and load overrun is prevented by a brake. Stapling is done at an exact pitch. This indexing can be applied extensively to food and other packaging machines.
SPEED AND SMALL FEED ANGLE (Feed frequency: N = 300 to 1,200 cycles/min.) (Feed angle: 0 = Up to 90°; N x 0 = 20,000 max) The example in Figure 16 shows a roll feeding device which is frequently used in high-speed automatic clamp presses. Driving power is taken from the eccentric disk provided at the end of the continuously rotating crankshaft, and this power drives the feed rolls intermittently through a Cam Clutch. The feed length can be changed quickly and easily for improved work efficiency. In order to attain high-speed, high-precision feeding, a cone brake with less torque fluctuation and a Cam Clutch for backstopping are used together.
Figure 16: Common roll feeding device utilizing indexing and backstop Cam Clutch
Figure 17: Automatic stapler indexing application
Typical Series
Advantage
For medium speeds (up to 300 cycles/min.) Excellent follow-up response at the time of engagement
MIUS
For low speed (up to 150 cycles/min.) Maintenance-free For low speeds (up to 100 cycles/min.) Same dimensions as #62 bearing
MZ, MZEU
BB
For low speeds (up to 150 cycles/min.) Sleeve-type outer race enables mounting of sprocket or gears as well as torque arms
PBUS
For medium speeds (up to 300 cycles/min.) Uses a special surface hardening cam to improve abrasion resistance
MI-S, MIUS-E, MIUS-K
For high speeds (up to 1,200 cycles/min.) Applicable also to low speeds
MX *
* Contact Tsubaki for more information.
www. ustsubaki .com
19
Indexing Clutch Selection Guide
(3) Indexing applications with: LOW SPEED AND LARGE FEED ANGLE (Feed frequency: N = Up to 150 cycles/min.) (Feed angle: 0 = 90° and up; N × 0 = 50,000 max.) Segmented gears and rack & pinions are often used to produce the reciprocal movement to be transmitted to the Cam Clutch. Figure 18 gives an application example of a pouch-making machine. Since the reciprocating movement of the eccentric disk is accelerated through the rack & pinion assembly, the reciprocal action of the Cam Clutch outer race is enlarged to 860°. During production the vinyl sheet feeding length is indexed at a speed of 40 to 60 cycles per minute. In this case, the acceleration of the Cam Clutch increases, a large torque acts repeatedly, and the cam slipping distance at overrunning becomes longer. Hence, a cam is required that has superior engagement and higher anti-abrasive properties. A brake is used in order to improve the precision of the vinyl sheet feeding pitch.
Figure 18: Indexing Cam Clutch used in feed roll application
Typical Series
Advantage
The MI-S Series has been developed exclusively for these applications
MI-S *
Special cam surface hardening treatment improves the abrasion wear
The shape and structure of the cam are specially designed so that it can handle abrupt speed changes (e.g. great acceleration) when engaging
* Contact Tsubaki for more information.
20
(4) Indexing applications with: FEEDING WITH STOPPER (Feed frequency: N = Up to 300 cycles/min.) (Feed angle: 0 = up to 90°) In this application, a stopper holds the material to be indexed at a position just before the feed end point, providing a fixed feeding pitch. As soon as the material hits the stopper, a torque shock load larger than the torque required for feeding is applied to the feeding roll which is still rotating. Figure 19 below shows an example of a Cam Clutch used in a bolt header. The wire is fed intermittently by a Cam Clutch mounted on a grooved feed roll. Since the feed length of the wire is set longer than necessary, the fed wire hits the stopper which has been set at a position where the wire is fed to the necessary length. The reactive force this generates acts as a vibrating shock load upon the Cam Clutch. It is therefore necessary to consider this when selecting a Cam Clutch.
(5) Indexing applications with: SPEED CHANGE (Feed frequency: N = Up to 300 cycles/min.) (Feed angle: 0 = Up to 90°; N × 0 = 20,000 max.) In an intermittent feed mechanism that uses one or more Cam Clutches, the speed of the driven side is changed steplessly by changing the feed angle. Figure 20 below shows an example of a manure spreader. The amount of manure to be sprinkled varies depending on the field conditions. The chain conveyor is driven by an intermittent Cam Clutch feeding action and the manure loaded on the cart is fed in bits to the continuously rotating sprinkling vanes. The manure to be sprinkled can thus be kept at the optimum amount by adjusting the amount of manure to be fed. The feed amount (or angle of the Cam Clutch) can be controlled steplessly while the sprinkler is operating.
Figure 19: Bolt header application utilizing indexing Cam Clutch
Figure 20: Manure Spreader
Typical Series
Advantage
MIUS
For medium speeds (Up to 300 cycles/min.)
MZEU, PBUS
For low speeds (Up to 150 cycles/min.)
BB
For low speeds (Up to 100 cycles/min.)
* Chart is for application (5) above only.
www. ustsubaki .com
21
Indexing Clutch Selection Guide
INDEXING SELECTION When detailed load conditions can be calculated, apply formula A, and when not, apply formula B and then compare with the allowable torque of the Cam Clutch. Please reference Figure 21 for critical dimensions associated with Formula B. Please contact Tsubaki with questions or for assistance.
Selection Procedure: a) Determine the design torque requirement b) Identify the maximum indexing cycles (N) per minute c) Specify the feeding angle 0 0 ≥ 90º consider MI-S Cam Clutch model (contact Tsubaki) 0 < 90º consider other series Cam Clutch d) Calculate the number of cycles per minute times the feed angle (N × 0 ) N × 0 ≤ 20,000 look at these Cam Clutches - MZ, MZEU, PBUS, BUS200, MIUS N × 0 ≤ 50,000 consider MI-S Cam Clutch model (contact Tsubaki) N × 0 > 50,000 please contact Tsubaki e) Identify the required bore size and installation method
Formula A:
Formula B:
9550 ∙ kW
ℓ 2 ℓ 1
∙ N 2
J ∙ O
∙
T =
x 2.5
T =
+ T B
n
10380
T: Loaded torque on Cam Clutch (Nm) J: Inertia of load (kgf ∙ m 2 ) on Cam Clutch shaft 0 : Feeding angle (deg) on Cam Clutch shaft N: Indexing cycles per minute (c/min) T B : Brake torque calculated on Cam Clutch shaft (Nm)
T: Loaded torque on Cam Clutch (Nm) kW: Transmitted power (kW) n: Speed of crank shaft (r/min) ℓ 1 : Length of crank ℓ 2 : Length of lever on Cam Clutch 2.5: Factor
Conversion factors for above calculations 1 Nm = 0.73756 lb.ft. 1 lb ∙ ft. = 1.356 Nm
1 kg ∙ m 2 = 23.73036 lb ∙ ft 2 1 lb ∙ ft 2 = 0.04214 kg ∙ m 2
1 kW = 1.34 hp 1 hp = 0.75 kw
Figure 21: Critical dimensions for indexing applications
22
Overrunning Clutch Selection Guide
OVERRUNNING: DUAL DRIVE AND TWO SPEED DRIVE Dual Drive is a system that utilizes two sets of driving units to propel a driven unit. Dual drive systems often have two drives that rotate at different speeds; these are referred to as two speed drive systems. In a two speed drive system, it is common to operate at two different speeds; high speed and low speed. Normally, each drive system utilizes a Cam Clutch that acts as an automatic switching device. In Figure 22 , when the driven unit is propelled by Driving Unit A (in the direction of the arrow), Cam Clutch A engages to transmit torque from the outer race to the inner race, resulting in rotation at a pre-set speed. At the same time, since the inner race of Cam Clutch B is also rotating in the same direction, it does not engage but overruns. The end result is Driving Unit B is disconnected from the Driven Unit. Conversely, when the Driven Unit is to be propelled by Driving Unit B, Cam Clutch B engages to transmit torque of the outer race to the inner race, resulting in rotation of the Driven Unit at a pre-set speed. At this time, Cam Clutch A overruns to disconnect Driving Unit A.
Cam
Cam
Outer race
Outer race
Driving unit A
Driving unit B
Driven unit
Inner race
Inner race
A Driving unit
A Cam clutch
B Cam clutch
B Driving unit
Driven unit
Figure 22: Dual Speed Drive System with Overrunning Cam Clutch
Overrunning Cam Clutch applications are divided into four types as depicted below. When selecting an overrunning Cam Clutch, one must consider the overrunning speed and engaging speed.
Application
Overrunning Speed
Engaging Speed
Applicable Series
High-speed overrunning and high-speed engagement High-speed overrunning and medium or low-speed engagement High-speed overrunning and low-speed engagement Medium and low-speed overrunning and medium and low-speed engagement
Cam Clutch Box MZEU, MZ Series Cam Clutch Box MZEU, MZ Series Cam Clutch Box BREU, BR-HT MZEU, MZ Series MZEU, MZ Series MGUS Series PBUS, BUS200
700 RPM and up
700 RPM and up
700 RPM and up
up to 700 RPM
700 RPM and up
Up to 200 RPM
up to 700 RPM
up to 700 RPM
www. ustsubaki .com
23
Overrunning Clutch Selection Guide
OVERRUNNING: DUAL DRIVE AND TWO SPEED DRIVE
High-Speed Overruning and High-Speed Engagement: (Overruning speed = 700 RPM and up) (Engaging speed = 700 RPM and up)
Example of fan or pump drive
Turbine
Reducer
Cam Clutch A
Cam Clutch B
Motor
Fan
Figure 23: Typical High-Speed Overrunning Application
Clutch B overruns when the turbine drives the fan, and it engages when the motor drives the fan. The driving devices can be changed over without switching the clutch. This is because the difference in the speed of rotation between the motor and turbine turns the Cam Clutches on and off, and the driving device rotating the fastest is connected automatically to the fan. Overrunning and engagement of the Cam Clutches are performed continuously at speeds faster than 700 r/min. Please reference Figure 23 . to drive a turbine. The turbine is then used to help drive the pump. If the pressure available is too low to rotate the turbine at high speed, the Cam Clutch overruns. However, when the rotating speed of the turbine reaches the rotating speed of the motor, the Cam Clutch engages automatically and the pump is driven by both the turbine, and the motor. Thus, power consumption equivalent to the turbine output can be saved. Since energy loss during overrunning and engagement of the Cam Clutch is extremely small, this system produces results for pumps with an output as low as 10 hp (7.5 kW). Setup requires only installation of a Cam Clutch and a turbine, providing a high efficiency energy recovery system with low running costs. Please reference Figure 24 .
This example shows a high-speed system in which a fan is driven by a dual drive system consisting of a motor and a turbine. The Cam Clutches are used for automatic switching between the driving units. The fan is normally driven by the Cam Clutch on the turbine side. When starting, or when steam pressure to the turbine drops, the motor takes over from the turbine to drive the fan. Cam Clutch A engages when the turbine drives the fan, and it overruns when the motor drives the fan. Conversely, Cam
Example of energy saving pump (power recovery system)
Hydraulic Turbine
Cam Clutch
Pump
Motor
Figure 24: High-Speed Energy Saving Application
Application of Cam Clutches in an energy saving pump (power recovery system) shows how highly effective energy saving can be achieved with the aid of Cam Clutches. The motor-driven pump discharges high-pressure liquid, which, after circulating, is used
24
Page 1 Page 2 Page 3 Page 4 Page 5 Page 6 Page 7 Page 8 Page 9 Page 10 Page 11 Page 12 Page 13 Page 14 Page 15 Page 16 Page 17 Page 18 Page 19 Page 20 Page 21 Page 22 Page 23 Page 24 Page 25 Page 26 Page 27 Page 28 Page 29 Page 30 Page 31 Page 32 Page 33 Page 34 Page 35 Page 36 Page 37 Page 38 Page 39 Page 40 Page 41 Page 42 Page 43 Page 44 Page 45 Page 46 Page 47 Page 48 Page 49 Page 50 Page 51 Page 52 Page 53 Page 54 Page 55 Page 56 Page 57 Page 58 Page 59 Page 60 Page 61 Page 62 Page 63 Page 64 Page 65 Page 66 Page 67 Page 68 Page 69 Page 70 Page 71 Page 72 Page 73 Page 74 Page 75 Page 76 Page 77 Page 78 Page 79 Page 80 Page 81 Page 82 Page 83 Page 84 Page 85 Page 86 Page 87 Page 88 Page 89 Page 90 Page 91 Page 92 Page 93 Page 94 Page 95 Page 96 Page 97 Page 98 Page 99 Page 100 Page 101 Page 102 Page 103 Page 104 Page 105 Page 106 Page 107 Page 108 Page 109 Page 110 Page 111 Page 112 Page 113 Page 114 Page 115 Page 116Made with FlippingBook Digital Proposal Creator