CA1123765A - Torque booster clutch with time delay - Google Patents
Torque booster clutch with time delayInfo
- Publication number
- CA1123765A CA1123765A CA326,067A CA326067A CA1123765A CA 1123765 A CA1123765 A CA 1123765A CA 326067 A CA326067 A CA 326067A CA 1123765 A CA1123765 A CA 1123765A
- Authority
- CA
- Canada
- Prior art keywords
- armature
- inner body
- clutch
- pockets
- engagement
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Landscapes
- Braking Arrangements (AREA)
Abstract
TORQUE BOOSTER CLUTCH WITH TIME DELAY
Abstract of the Disclosure An electromagnetic clutch having an armature drawn into engagement with an inner body upon energization of the clutch to establish a driving connection through the clutch, and having an arrangement to increase the engagement force between the armature and inner body to increase the torque capacity of the clutch. The arrangement includes a plurality of balls cooperating with corresponding pockets which act to force the armature into tighter engagement with the inner body. The disclosed clutch incorporates a time delay of the action of the torque boosting ball and pocket arrangement by forming at least one of the sets of pockets with elongated sections, allowing free movement without acting on the armature until after a pre-determined extent of relative rotation has occured. A return torsion spring positions the balls And pockets in the proper initial position.
Abstract of the Disclosure An electromagnetic clutch having an armature drawn into engagement with an inner body upon energization of the clutch to establish a driving connection through the clutch, and having an arrangement to increase the engagement force between the armature and inner body to increase the torque capacity of the clutch. The arrangement includes a plurality of balls cooperating with corresponding pockets which act to force the armature into tighter engagement with the inner body. The disclosed clutch incorporates a time delay of the action of the torque boosting ball and pocket arrangement by forming at least one of the sets of pockets with elongated sections, allowing free movement without acting on the armature until after a pre-determined extent of relative rotation has occured. A return torsion spring positions the balls And pockets in the proper initial position.
Description
3', ~5 Background Discussion .
Typically, electromagnetically operated clutches and brakes are operated by an electromagnetic coil which serves to draw a clutching member into driving engagement by virtue of the magnetic attraction between ferromagnetic members of the clutch. Such electromagnetic clutches often include a torque boosting arrangement in which the engagement pressure of the clutching members is increased mechanically so as to augment the engagement pressure created by the electrmagnetic force.
A typical example is as dislcosed in U.S. patent 2,816,636 to Wiebel, Jr. (Dec. 17, 1957). The torque booster often takes the form disclosed in that patent, i.e., a plurality of balls are disposed in corresponding pocket sets in the clutching members with a camming action created between the balls in the pockets upon relative rotation occurring between the clutching members, upon energization of the electromagnetic coil. These camming forces serve to greatly increase the engagement pressure.
A similar such unit is described in U.S . Patent 3,000, 479 to Mosbacher (Sept. 19, 1961) in which the ball-pocket arrange-ment is utilized in conjuction with the pilot clutch to operatea main clutch. The use of the ball pocket operators is also commonly incorporated into clutch-brake units other than electro-magnetically operated clutches as disclosed in U.S. patent number 3,158,241 to Bloom (Nov. 24, 1964) in which a temperature sensitive spring induces drag on the clutch disc to cause the ball pocket camming means to come into play.
In U.S. patent 4,079,821 to Miller (Mar. 21, 1978), there is dislcosed an electromagnetically operated clutch of a design unique in several respects,in which the balls are utilized to transmit -the torque through the clutch unit as well as to in-crease the engagement pressure between an armature and the pole faces of an inner body upon energization of the electromagnetic - 1 - ~;
1~ 3~5 coil. As described in that patent application, the clutch according to that design, develops full torque potential almos-instantaneously due to the re]ationship between the pockets and the axial movement of the armature upon energization of the electromagnetic coil operator. This clutch does not utilize friction disc at the engagement surfaces but rather there is a metal to metal contact, which results in very little axial motion of the armature developing full torque. This is in contrast to the clutch designs described in the above reference U.S. patents.
While having many advantages over simple electromagnetic clutches, the extremely rapid action of the clutch in developing full torque maybe too rapid for some clutch applications. While such a delay could be build into the clutch unit by appropriate circuit controls modifying the actuation timing by modifying the time of energization of the coil. This adds significantly to the costs of the unit.
It is, accordingly, an object of the present invention to provide a clutch-brake unit of the type incorporating ball-pocket torque boosting arrangement which serve to delay full torque build-up in the clutch-brake unit, without necessitating the use of modifications to the external controls of the unit.
It is yet another object of the present invention to provide such a built-in delay which operates simply and reliably ,...
;~ without adding appreciably to the complexity of the unit.
Summary of the Inventi-on These and other objects which will become apparent upon a reading of the following specification and claims is accompli-shed by an arrangement in the clutch-brake unit utilizing such a ball-pocket operator, with an elongated section formed in the pocket in at least one of the opposed pocket sets, the sections adjacent the pccket ramping surfaces, and with bias spring means for positioning the balls and pockets in the intial position Z3 ~S
such that a relative predetermined extent of rotation through the pocket section occurs prior to engagement of the ramping surface of the pocket. The elongated section is contoured such that no camming action takes place as the balls traverse this section af the pockets, so that the action of the ball-pocket torque booster or operator is delayed a time interval corresponding to the length of the elongated pocket section and the relative rotational speed between the members formed with the pocket sets. The initial positioning may be accomplished by a torsional spring biasing the clutch members having the pockets formed - therein to a relative position such that the balls will traversethe non-camming section of the pockets prior to encountering the ramping surfaces.
Description of the Drawings Figure 1 is a view of an electromagnetically operated - clutch-brake unit according to the present invention shown in actual longitudinal section.
Figure 2 is an endwise view of the pulley member in-corporated in the clutch-brake unit depicted in Figure 1.
~ 20 Detailed Description - In the following detailed description, certain termin-ology will be employed for the sake of clarity and a particular embodiment described, but it is to be understood that the same - is not intended to be limiting and should not be so construed in as much as the invention is capable of taking many other forms and variations within the scope of the appended claims. For example, the embodiment described is an electromagnetically operated clutch, whereas the same unit may be employed as a brake, i.e., to control the driving engagement of a rotary member witl a stationary member.
Referring to the drawings, particularly Figure 1, an electromagnetically operated clutch 10 is depicted which is des-37~5 signed to establish a rotative driving connection between first and second driving members, one of which serving as an input member, the other of which serving as the output. Since either of the first or second driving members may be utilized as the input or conversely the output, the terminology "first" and "second" driving members will be employed in describing the clutch members which are controllably connected by the clutch 10.
The first driving member here takes the form of a pulley member 12 rotatably mounted on a bearing set 14. The second driving member 16 comprises a shaft concentric to the pulley or axially aligned with the pulley 12. The clutch 10 includes means for controllably establishing a driving connection between the pulley 12 and the shaft 16 which means includes an inner body 18 which is axially aligned with the pulley 12 and the shaft 16 and adapted to be rotatably connected to the shaft 16. The inner body 18 is axially and rotatably mounted by means of bearings 20 and 22 which provide a rotational support on a mag body 24, which is a stationary structure mounted to a stationary mounting structure by means of a strap 26.
The inner body 18 has a radially extending flange por-tion generally indicated at 28 which has formed a pair of pole faces, an outer pole face 30 and an inner pole face 32. The inner pole face 32 and an outer pole face 30 are separated by a non-ferromagnetic spacer ring 34. The remaining portions of the inner body 18 is formed of a ferromagnetic meterial such as steel.
Disposed opposite the inner body 18 is the clutch arma-ture 36 which has a pair of radial faces 38 and 40. The radial face 38 is disposed opposite the pole faces 30 and 32 formed on the inner body 18, The armature 36 is mounted to be relatively movable axially with respect to the inner body 18 so as to bring the radial face 38 into and out of engagement with the inner body pole 3~S
faces 30 and 32. This movement is against the bias ol an arma-ture return spring 41 which is seated on a radial flange 42 joined to an inner ring 44 integral with the pulley 12. Thc pulley 12 in turn is axially located by means of a thrust washer 46 seated against the flange 48 of a collar member 50 in turn seated against the bearing set 14.
Relative axial movement of the armature 36 is induced by the electromagnetic operator means including an electromag-netic coil 52 which is diposed such that when energized via the leads 54, a magnetic clux is induced, passing through the inner body 18 via outer and inner pole faces 30 and 32 and through the ~- armature 36, creating a magnetic attraction between the armature 36 and the inner body 18.
The armature 36 is constructed of ferromagnetic material to provide a magentic flux path and to be capable of being mag-netized by the passage of magnetic flux therethrough. The spacer ring 34 is of non-ferromagnetic construction, to create the magnetic flux circuit through the armature 36.
The radial face 40 formed on the armature 36, and the opposite r.adial face 56 is formed in the pulley 12 are provided with respective sets of pockets 58 and 60, here shown as three pockets in each set. Disposed in opposing pockets 58 and 60 is a corresponding plurality of balls 62. The balls 62 and the pockets 58 and 60 comprise torque booster means by the camming action created between the balls 62 and the pockets 58 and 60.
This occurs upon relative rotative movement between the pulley 12 and the armature 36, when the armature 36 is draw`into ro-tative engagement with the pole faces 30 and 32, and a driving input either via pulley 12 or shaft 16 causes an initial torque to be transmitted. This in turn causes a camming action between the balls 62, and the pockets 58 and 60 by ramping of the balls on the sloping surfaces 64 and 66 formed on the respective pockets 3 i ~ S
58 and 60.
This augments the engagement pressure created by the electromagnetic operator means to develop the full torque capaci-ty of the clutch-brake 10. In the aforementioned patent number 4,079,821 to Miller, the pockets 58 and 60 are of conical shape such that upon movement of the armature 36 into engagement with the inner body pole face 30 and 32, the camming actionis nearly instantaneous such that full torque is generated as discussed above.
According to the concept of the present invention, in order to delay the development of full torque through the clutch at least one of the pockets in the pocket sets 58 or 60 is elongated as can be seen in Figure 2. Here, the pockets 60 being shown as elongated such that the conical ramp surfaces 66 are not encountered by the balls 62 until the balls 62 have moved to the end of the pockets 60. The intermediate sections 68 are thus of a contour such that the ramping or camming action does not occur upon a relative rotative movement between the armature 36 and the pulley 12, until the relative rotation occurs, of a predetermined extent determined by the length of the inter-mediate length of the section 68.
Thus, if the pulley 12 and the armature 36 are initial-ly positioned so that upon energization ofthe electromagnetic coil 52, the relative rotation is in a direction such as to re-quire movement of the balls 62 through the elongated section 68 before encountering the conical ramp surface at the far end of the pocket 60, the torque boosting action of the balls and the pockets will be delayed an interval of time corresponding to the length of the relative movement required.
Thus, depending on relative speed of rotation between the armature 36 and pulley 12, a predetermined delay will be .introduced before the torque booster arrangement comes into op-~ ~3~iS
eration and the clutch develops its full torque.
In order to properly position the armature 36 and the radial face 56 in the rest position, i.e. before the clutch 10 is activated, spring bias means are employed urging the arma-ture 36 and the pulley 12 to rotate relative each other in a direction such as to cause the ball 62 to be positioned within the elongated pockets 60 at the far end of the pocket 60 from the end which engages the balls upoin establishment of a driving con-nection through the clutch. That is, the direction ofrelative rotation urged by the spring bias is in the opposite direction from the relative rotation occurring upon engagement of the ar-mature with the inner body. This causes the armature 36 and the pulley 12 to assume the position with the balls 62 in abutment against the far end of the pockets 60 opposite the ramping surface causing the torque booster action.
The sping bias means can take the form of the torsional return sping 70 having one end 72 anchored in a pocket formed in the armature 36, and the other end 74 inserted in a corresponding pocket formed in the radial face 56 on the pulley 12 as indicated.
This exerts a spring bias torsional force between the armature 36 and the pulley 12.
Accoridingly, upon energization of the electromagnetic coil 52, the armature 36 is axially drawn into engagement with the pole faces 30 and 32 of the inner body 18. The relative rotation induced by a torque being transmitted through the clutch 10 at this point produces a relative rotation between the armature 36 and the pulley 12 causing the balls 62 to move relative the pocket 60 through the elongated intermediate section 68 of the pocket 60 into engagement with the conical sloping end surface of the pocket 60 at the far end of each slot. Upon engagement of these surfaces, the torque booster action comes into play, increasing the axial force tending to urge the armature 36 into ~ 3 J ~5 ,. .
`~ engagement with the pole faces 30 and 36 and developing the full torque capacity of the clutch.
It can be appreciated that the objects of the present invention have been achieved by the design described, in that a controllable time delay is built into the clutch itself, which does not require any modi~ication of the external control circuit in order to delay the action of the clutch in developing full torque.
As noted, the circumferential length of the elongated pockets 60 and the speed of the input shaft controls the duration of the time delay. For example, assuming the shaft 16 is the input member, if the shaft 16 is rotating at 240 rpm which is 4 revolutions per second, this equals 1,440 degrees per second or ~ 1.4 degrees per millisecond. If the delay required is 30 milli-- seconds, the length of the elongated ball pockets required would ~'' .
be 1.4 times 30 or 42 degrees.
While a single set of the pockets 60 have been des-cribed as elongated circumferentially, both pockets could be el-- ongated such that the delay would be additive, and correspond !.~ 20 to the combined length of the respective corresponding pockets ' 58 and 60.
While the application is advantageous in the context of the specific electromagnetic clutch design described due to its unusually rapid action, it would be possible to apply the same concept to other clutch designs incorporating ball-pocket boosters or operators in order to introduce a mechanically built-in time delay in the action ofthe clutch. Further, many variation in the specifics described are, of course, possible as alternate spring torsional bias arrangement or other means for assuring that the balls are positioned relative to the elon-gated pockets in the initial rest position such as that proper traversing thereof by the balls occurs upon initial establish-ment of the driving connection.
Typically, electromagnetically operated clutches and brakes are operated by an electromagnetic coil which serves to draw a clutching member into driving engagement by virtue of the magnetic attraction between ferromagnetic members of the clutch. Such electromagnetic clutches often include a torque boosting arrangement in which the engagement pressure of the clutching members is increased mechanically so as to augment the engagement pressure created by the electrmagnetic force.
A typical example is as dislcosed in U.S. patent 2,816,636 to Wiebel, Jr. (Dec. 17, 1957). The torque booster often takes the form disclosed in that patent, i.e., a plurality of balls are disposed in corresponding pocket sets in the clutching members with a camming action created between the balls in the pockets upon relative rotation occurring between the clutching members, upon energization of the electromagnetic coil. These camming forces serve to greatly increase the engagement pressure.
A similar such unit is described in U.S . Patent 3,000, 479 to Mosbacher (Sept. 19, 1961) in which the ball-pocket arrange-ment is utilized in conjuction with the pilot clutch to operatea main clutch. The use of the ball pocket operators is also commonly incorporated into clutch-brake units other than electro-magnetically operated clutches as disclosed in U.S. patent number 3,158,241 to Bloom (Nov. 24, 1964) in which a temperature sensitive spring induces drag on the clutch disc to cause the ball pocket camming means to come into play.
In U.S. patent 4,079,821 to Miller (Mar. 21, 1978), there is dislcosed an electromagnetically operated clutch of a design unique in several respects,in which the balls are utilized to transmit -the torque through the clutch unit as well as to in-crease the engagement pressure between an armature and the pole faces of an inner body upon energization of the electromagnetic - 1 - ~;
1~ 3~5 coil. As described in that patent application, the clutch according to that design, develops full torque potential almos-instantaneously due to the re]ationship between the pockets and the axial movement of the armature upon energization of the electromagnetic coil operator. This clutch does not utilize friction disc at the engagement surfaces but rather there is a metal to metal contact, which results in very little axial motion of the armature developing full torque. This is in contrast to the clutch designs described in the above reference U.S. patents.
While having many advantages over simple electromagnetic clutches, the extremely rapid action of the clutch in developing full torque maybe too rapid for some clutch applications. While such a delay could be build into the clutch unit by appropriate circuit controls modifying the actuation timing by modifying the time of energization of the coil. This adds significantly to the costs of the unit.
It is, accordingly, an object of the present invention to provide a clutch-brake unit of the type incorporating ball-pocket torque boosting arrangement which serve to delay full torque build-up in the clutch-brake unit, without necessitating the use of modifications to the external controls of the unit.
It is yet another object of the present invention to provide such a built-in delay which operates simply and reliably ,...
;~ without adding appreciably to the complexity of the unit.
Summary of the Inventi-on These and other objects which will become apparent upon a reading of the following specification and claims is accompli-shed by an arrangement in the clutch-brake unit utilizing such a ball-pocket operator, with an elongated section formed in the pocket in at least one of the opposed pocket sets, the sections adjacent the pccket ramping surfaces, and with bias spring means for positioning the balls and pockets in the intial position Z3 ~S
such that a relative predetermined extent of rotation through the pocket section occurs prior to engagement of the ramping surface of the pocket. The elongated section is contoured such that no camming action takes place as the balls traverse this section af the pockets, so that the action of the ball-pocket torque booster or operator is delayed a time interval corresponding to the length of the elongated pocket section and the relative rotational speed between the members formed with the pocket sets. The initial positioning may be accomplished by a torsional spring biasing the clutch members having the pockets formed - therein to a relative position such that the balls will traversethe non-camming section of the pockets prior to encountering the ramping surfaces.
Description of the Drawings Figure 1 is a view of an electromagnetically operated - clutch-brake unit according to the present invention shown in actual longitudinal section.
Figure 2 is an endwise view of the pulley member in-corporated in the clutch-brake unit depicted in Figure 1.
~ 20 Detailed Description - In the following detailed description, certain termin-ology will be employed for the sake of clarity and a particular embodiment described, but it is to be understood that the same - is not intended to be limiting and should not be so construed in as much as the invention is capable of taking many other forms and variations within the scope of the appended claims. For example, the embodiment described is an electromagnetically operated clutch, whereas the same unit may be employed as a brake, i.e., to control the driving engagement of a rotary member witl a stationary member.
Referring to the drawings, particularly Figure 1, an electromagnetically operated clutch 10 is depicted which is des-37~5 signed to establish a rotative driving connection between first and second driving members, one of which serving as an input member, the other of which serving as the output. Since either of the first or second driving members may be utilized as the input or conversely the output, the terminology "first" and "second" driving members will be employed in describing the clutch members which are controllably connected by the clutch 10.
The first driving member here takes the form of a pulley member 12 rotatably mounted on a bearing set 14. The second driving member 16 comprises a shaft concentric to the pulley or axially aligned with the pulley 12. The clutch 10 includes means for controllably establishing a driving connection between the pulley 12 and the shaft 16 which means includes an inner body 18 which is axially aligned with the pulley 12 and the shaft 16 and adapted to be rotatably connected to the shaft 16. The inner body 18 is axially and rotatably mounted by means of bearings 20 and 22 which provide a rotational support on a mag body 24, which is a stationary structure mounted to a stationary mounting structure by means of a strap 26.
The inner body 18 has a radially extending flange por-tion generally indicated at 28 which has formed a pair of pole faces, an outer pole face 30 and an inner pole face 32. The inner pole face 32 and an outer pole face 30 are separated by a non-ferromagnetic spacer ring 34. The remaining portions of the inner body 18 is formed of a ferromagnetic meterial such as steel.
Disposed opposite the inner body 18 is the clutch arma-ture 36 which has a pair of radial faces 38 and 40. The radial face 38 is disposed opposite the pole faces 30 and 32 formed on the inner body 18, The armature 36 is mounted to be relatively movable axially with respect to the inner body 18 so as to bring the radial face 38 into and out of engagement with the inner body pole 3~S
faces 30 and 32. This movement is against the bias ol an arma-ture return spring 41 which is seated on a radial flange 42 joined to an inner ring 44 integral with the pulley 12. Thc pulley 12 in turn is axially located by means of a thrust washer 46 seated against the flange 48 of a collar member 50 in turn seated against the bearing set 14.
Relative axial movement of the armature 36 is induced by the electromagnetic operator means including an electromag-netic coil 52 which is diposed such that when energized via the leads 54, a magnetic clux is induced, passing through the inner body 18 via outer and inner pole faces 30 and 32 and through the ~- armature 36, creating a magnetic attraction between the armature 36 and the inner body 18.
The armature 36 is constructed of ferromagnetic material to provide a magentic flux path and to be capable of being mag-netized by the passage of magnetic flux therethrough. The spacer ring 34 is of non-ferromagnetic construction, to create the magnetic flux circuit through the armature 36.
The radial face 40 formed on the armature 36, and the opposite r.adial face 56 is formed in the pulley 12 are provided with respective sets of pockets 58 and 60, here shown as three pockets in each set. Disposed in opposing pockets 58 and 60 is a corresponding plurality of balls 62. The balls 62 and the pockets 58 and 60 comprise torque booster means by the camming action created between the balls 62 and the pockets 58 and 60.
This occurs upon relative rotative movement between the pulley 12 and the armature 36, when the armature 36 is draw`into ro-tative engagement with the pole faces 30 and 32, and a driving input either via pulley 12 or shaft 16 causes an initial torque to be transmitted. This in turn causes a camming action between the balls 62, and the pockets 58 and 60 by ramping of the balls on the sloping surfaces 64 and 66 formed on the respective pockets 3 i ~ S
58 and 60.
This augments the engagement pressure created by the electromagnetic operator means to develop the full torque capaci-ty of the clutch-brake 10. In the aforementioned patent number 4,079,821 to Miller, the pockets 58 and 60 are of conical shape such that upon movement of the armature 36 into engagement with the inner body pole face 30 and 32, the camming actionis nearly instantaneous such that full torque is generated as discussed above.
According to the concept of the present invention, in order to delay the development of full torque through the clutch at least one of the pockets in the pocket sets 58 or 60 is elongated as can be seen in Figure 2. Here, the pockets 60 being shown as elongated such that the conical ramp surfaces 66 are not encountered by the balls 62 until the balls 62 have moved to the end of the pockets 60. The intermediate sections 68 are thus of a contour such that the ramping or camming action does not occur upon a relative rotative movement between the armature 36 and the pulley 12, until the relative rotation occurs, of a predetermined extent determined by the length of the inter-mediate length of the section 68.
Thus, if the pulley 12 and the armature 36 are initial-ly positioned so that upon energization ofthe electromagnetic coil 52, the relative rotation is in a direction such as to re-quire movement of the balls 62 through the elongated section 68 before encountering the conical ramp surface at the far end of the pocket 60, the torque boosting action of the balls and the pockets will be delayed an interval of time corresponding to the length of the relative movement required.
Thus, depending on relative speed of rotation between the armature 36 and pulley 12, a predetermined delay will be .introduced before the torque booster arrangement comes into op-~ ~3~iS
eration and the clutch develops its full torque.
In order to properly position the armature 36 and the radial face 56 in the rest position, i.e. before the clutch 10 is activated, spring bias means are employed urging the arma-ture 36 and the pulley 12 to rotate relative each other in a direction such as to cause the ball 62 to be positioned within the elongated pockets 60 at the far end of the pocket 60 from the end which engages the balls upoin establishment of a driving con-nection through the clutch. That is, the direction ofrelative rotation urged by the spring bias is in the opposite direction from the relative rotation occurring upon engagement of the ar-mature with the inner body. This causes the armature 36 and the pulley 12 to assume the position with the balls 62 in abutment against the far end of the pockets 60 opposite the ramping surface causing the torque booster action.
The sping bias means can take the form of the torsional return sping 70 having one end 72 anchored in a pocket formed in the armature 36, and the other end 74 inserted in a corresponding pocket formed in the radial face 56 on the pulley 12 as indicated.
This exerts a spring bias torsional force between the armature 36 and the pulley 12.
Accoridingly, upon energization of the electromagnetic coil 52, the armature 36 is axially drawn into engagement with the pole faces 30 and 32 of the inner body 18. The relative rotation induced by a torque being transmitted through the clutch 10 at this point produces a relative rotation between the armature 36 and the pulley 12 causing the balls 62 to move relative the pocket 60 through the elongated intermediate section 68 of the pocket 60 into engagement with the conical sloping end surface of the pocket 60 at the far end of each slot. Upon engagement of these surfaces, the torque booster action comes into play, increasing the axial force tending to urge the armature 36 into ~ 3 J ~5 ,. .
`~ engagement with the pole faces 30 and 36 and developing the full torque capacity of the clutch.
It can be appreciated that the objects of the present invention have been achieved by the design described, in that a controllable time delay is built into the clutch itself, which does not require any modi~ication of the external control circuit in order to delay the action of the clutch in developing full torque.
As noted, the circumferential length of the elongated pockets 60 and the speed of the input shaft controls the duration of the time delay. For example, assuming the shaft 16 is the input member, if the shaft 16 is rotating at 240 rpm which is 4 revolutions per second, this equals 1,440 degrees per second or ~ 1.4 degrees per millisecond. If the delay required is 30 milli-- seconds, the length of the elongated ball pockets required would ~'' .
be 1.4 times 30 or 42 degrees.
While a single set of the pockets 60 have been des-cribed as elongated circumferentially, both pockets could be el-- ongated such that the delay would be additive, and correspond !.~ 20 to the combined length of the respective corresponding pockets ' 58 and 60.
While the application is advantageous in the context of the specific electromagnetic clutch design described due to its unusually rapid action, it would be possible to apply the same concept to other clutch designs incorporating ball-pocket boosters or operators in order to introduce a mechanically built-in time delay in the action ofthe clutch. Further, many variation in the specifics described are, of course, possible as alternate spring torsional bias arrangement or other means for assuring that the balls are positioned relative to the elon-gated pockets in the initial rest position such as that proper traversing thereof by the balls occurs upon initial establish-ment of the driving connection.
Claims (9)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An electromagnetic clutch-brake comprising: a first drive member; a second drive member; means for rotatably supporting said first and second drive members in axial align-ment; means for controllably establishing a rotative driving connection between said first and second members, said means including: a ferromagnetic armature mounted in axial alignment with said first and second members and having a radial face on either side thereof; an inner body rotatably mounted in axial alignment with said first and second drive members and said armature, said armature and inner body being mounted for rela-tive axial movement therebetween, said inner body having ferro-magnetic radial pole faces disposed opposite a radial face of said armature; a return spring urging said inner body and arma-ture apart; electromagnetic operator means including an electro-magnetic coil, said electromagnetic coil being mounted to cause magnetic flux through said inner body and said armature to cause said armature and inner body to be draw into engagement with each other by relative axial movement upon energization of said electromagnetic coil; means drivingly connecting said armature and said inner body to a repsective one of said first or second drive members; torque booster means comprising a plurality of circumferentially spaced balls disposed in corresponding sets of pockets formed in a radial face of said armature and in an opposed radial surface axially fixed with respect to said armature and rotatably fixed with respect to said drive member drivingly connected to said armature, each of said pockets having ramping surfaces adapted to cause said balls to urge said armature into tighter engagement with said inner body pole faces upon relative rotation between said radial surface and said armature induced by engagement of said armature with said inner body pole faces;
said pockets of at least one of said sets of pockets, each having an elongated section adjacent said rmaping surface contoured to allow relative rotation of said armature and surface without causing said axial movement therebetween; bias spring means urging said armature and said radial surface into a relative rotative position whereat said balls are positioned in said at least one set of pockets in said elongated sections remote from said ramping surfaces, whereby said torque booster action is delayed until a predetermined extent of relative rotation has occurred sufficient for said plurality of balls to move into engagement with said ramping surfaces.
said pockets of at least one of said sets of pockets, each having an elongated section adjacent said rmaping surface contoured to allow relative rotation of said armature and surface without causing said axial movement therebetween; bias spring means urging said armature and said radial surface into a relative rotative position whereat said balls are positioned in said at least one set of pockets in said elongated sections remote from said ramping surfaces, whereby said torque booster action is delayed until a predetermined extent of relative rotation has occurred sufficient for said plurality of balls to move into engagement with said ramping surfaces.
2. The clutch-brake according to Claim 1 wherein, said bias spring means comprises a torsion spring urging relative rotation between said armature and said radial surface in an op-posite direction to the direction of said relative rotation be-tween said armature and said inner body upon engagement thereof.
3. The clutch-brake according to Claim 1 wherein, said opposed radial face is formed on said drive member drivingly connected to said armature.
4. A clutch-brake of the type having opposing rotary drive members selectively brought into driving engagement, and including a ball-pocket operator means comprising a plurality of balls disposed in corresponding opposed pocket sets in said respective opposing rotary drive members urging said drive mem-bers into said driving engagement upon relative rotation between said drive members, the improvement comprising: delay means causing said action of said ball-pocket means to be delayed for a predetermined extent of relative rotation between said drive members, whereby the build-up of torque in said clutch-brake unit between said drive members is delayed.
5. The clutch-brake unit according to claim 4, wherein said delay means comprises forming said pockets with elongated straight contoured sections which allow relative movement be-tween said balls and pockets without urging said drive members into engagement.
6. The clutch-brake unit according to claim 5, wherein said delay means further includes bias spring means positioning said balls ins aid pockets to allow said relative movement prior to engagement of said drive members.
7. An electromagnetic clutch-brake comprising: a first dirve member; a second drive member; means for rotatably supporting said first and second drive members in axial align-ment; means for controllably establishing a rotative driving con-nection between said first and second members, said means inclu-ding: a ferromagnetic armature mounted in axial alignment with said first and second drive members and having a radial face on either side thereof; an inner body rotatably mounted in axial alignment with said first and second drive members and said armature, said armature and inner body being mounted for relative axial movement therebetween, said inner body having ferromagnetic radial pole faces disposed opposite a radial face of said armature; a return spring urging said inner body and armature apart;
electromagnetic operator means including an electromagnetic coil, said electromagnetic coil being mounted to cause magnetic flux through said inner body and said armature to cause said armature and inner body to be drawn into engage-ment with each other by relative axial movement upon energization of said electromagnetic coil;
means drivingly connecting said armature and said inner body to a respective one of said first or second drive members;
torque booster means comprising a plurality of circumferentially spaced balls disposed in corresponding sets of pockets formed in a radial face of said armature and in an opposed radial surface axially fixed with respect to said armature and rotatably fixed with respect to said drive member drivingly connected to said armature, each of said sets of pockets having at least two ramping surfaces adapted to cause one of said plurality of circumferentially spaced balls to urge said armature into tighter engagement with said inner body pole faces upon relative rotation between said opposed radial surface and said radial face of the armature induced by engagement of said armature with said inner body pole faces; at least one pocket of each set of said pockets of said corresponding sets of pockets further having a predetermined elongated non-camming section adjacent said ramping surface to allow a predetermined relative rotation of said armature and said radial surface without causing axial movement therebetween;
bias spring means urging said armature and said radial surface into a relative rotative position whereat said balls are positioned in said at least one set of pockets in said elongated sections remote from said ramping surfaces, whereby said torque booster action is delayed until a predeter-mined extent of relative rotation has occurred sufficient for said plurality of balls to move into engagement with said ramping surfaces.
electromagnetic operator means including an electromagnetic coil, said electromagnetic coil being mounted to cause magnetic flux through said inner body and said armature to cause said armature and inner body to be drawn into engage-ment with each other by relative axial movement upon energization of said electromagnetic coil;
means drivingly connecting said armature and said inner body to a respective one of said first or second drive members;
torque booster means comprising a plurality of circumferentially spaced balls disposed in corresponding sets of pockets formed in a radial face of said armature and in an opposed radial surface axially fixed with respect to said armature and rotatably fixed with respect to said drive member drivingly connected to said armature, each of said sets of pockets having at least two ramping surfaces adapted to cause one of said plurality of circumferentially spaced balls to urge said armature into tighter engagement with said inner body pole faces upon relative rotation between said opposed radial surface and said radial face of the armature induced by engagement of said armature with said inner body pole faces; at least one pocket of each set of said pockets of said corresponding sets of pockets further having a predetermined elongated non-camming section adjacent said ramping surface to allow a predetermined relative rotation of said armature and said radial surface without causing axial movement therebetween;
bias spring means urging said armature and said radial surface into a relative rotative position whereat said balls are positioned in said at least one set of pockets in said elongated sections remote from said ramping surfaces, whereby said torque booster action is delayed until a predeter-mined extent of relative rotation has occurred sufficient for said plurality of balls to move into engagement with said ramping surfaces.
8. The clutch-brake according to claim 1, wherein said bias spring means comprises a torsion spring urging relative rotation between said armature and said radial surface in an opposite direction to the direction of said relative rotation between said armature and said inner body upon engagement thereof.
9. The clutch-brake according to claim 1, wherein said opposed radial face is formed on said drive member drivingly connected to said armature.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US89905078A | 1978-04-24 | 1978-04-24 | |
| US899,050 | 1978-04-24 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1123765A true CA1123765A (en) | 1982-05-18 |
Family
ID=25410423
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA326,067A Expired CA1123765A (en) | 1978-04-24 | 1979-04-23 | Torque booster clutch with time delay |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JPS54141942A (en) |
| CA (1) | CA1123765A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6561332B2 (en) | 2000-04-17 | 2003-05-13 | Eaton Corporation | Ball ramp clutch with frictional damping |
| US6637569B1 (en) | 2002-05-09 | 2003-10-28 | Eaton Corporation | Ball ramp actuator with indexing plates |
| US6666315B2 (en) | 2002-05-09 | 2003-12-23 | Eaton Corporation | Ball ramp clutch with indexing plates |
| US6675943B2 (en) | 2002-05-09 | 2004-01-13 | Eaton Corporation | Lubrication system for ball ramp clutch systems |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4079821A (en) * | 1976-05-17 | 1978-03-21 | Facet Enterprises, Inc. | Electromagnetic clutch |
-
1979
- 1979-04-23 CA CA326,067A patent/CA1123765A/en not_active Expired
- 1979-04-24 JP JP4984879A patent/JPS54141942A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6561332B2 (en) | 2000-04-17 | 2003-05-13 | Eaton Corporation | Ball ramp clutch with frictional damping |
| US6637569B1 (en) | 2002-05-09 | 2003-10-28 | Eaton Corporation | Ball ramp actuator with indexing plates |
| US6666315B2 (en) | 2002-05-09 | 2003-12-23 | Eaton Corporation | Ball ramp clutch with indexing plates |
| US6675943B2 (en) | 2002-05-09 | 2004-01-13 | Eaton Corporation | Lubrication system for ball ramp clutch systems |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS54141942A (en) | 1979-11-05 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US2937729A (en) | Magnetic friction clutch with stationary field | |
| US3865222A (en) | Electromagnetic spring-wound clutch | |
| US5967274A (en) | Wrap spring clutch/brake assembly having soft start and soft stop capabilities | |
| US4445596A (en) | Electromagnetically released spring applied friction brake with torque booster and driving force distributor | |
| US3735847A (en) | Electromagnetic spring-wound clutch | |
| US5847478A (en) | Electro-magnetic clutch | |
| US8256598B2 (en) | Permanent magnet wrap spring clutch | |
| US4263995A (en) | Electromagnetic spring clutch | |
| CA1099773A (en) | Electromagnetic clutch | |
| JP3125160B2 (en) | Armature assembly for electromagnetic coupling | |
| US2718292A (en) | Magnetic clutch | |
| US3994379A (en) | Self-adjusting electromagnetic clutch | |
| US3789966A (en) | Self-adjusting electromagnetic disc clutch | |
| US3966024A (en) | Helical spring clutch | |
| US3337013A (en) | Electromagnetically controlled clutch and brake organization | |
| CA1123765A (en) | Torque booster clutch with time delay | |
| US4466522A (en) | Electromagnetic spring-wound clutch | |
| US4189042A (en) | Constant torque friction clutch | |
| US4103763A (en) | Braking device for drive motors | |
| US6047805A (en) | Electric clutch and brake | |
| US2664981A (en) | Electromagnetically controlled friction clutch | |
| US3297122A (en) | Wear take-up device for magnetic friction couplings | |
| US6637569B1 (en) | Ball ramp actuator with indexing plates | |
| US4184577A (en) | Electromagnetic clutch with two stage torque buildup | |
| US4630722A (en) | Electromagnetic wrap spring clutch |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |