JP2009156301A - Reverse input cut-off clutch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reverse input cut-off clutch capable of achieving both secure cut-off of reverse input and stable transmission of large positive input. <P>SOLUTION: Movable elements 7, 7 supported so as to enable radial movement and coaxial rotation of an input disk 5 and an output disk 6 are opposed to the peripheral face of the output disk 6 from outside, and are energized in the direction separated from the peripheral face of the output disk 6 by an annular leaf spring 8. A pair of pressing elements 52, 52 rotated cooperatively with the input disk 5 are arranged on both sides of the movable elements 7, 7. The pressing elements 52, 52 act on the movable elements 7, 7 by the rotation of the input rotating body 5 and press down the movable elements 7, 7, resisting to the energizing of the leaf spring 8. Irregular parts 72 provided on the movable elements 7, 7 are engaged with irregular parts 61 provided on the peripheral face of the output disk 6. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a reverse input cutoff clutch used in various transmission systems to cut off a reverse input from an output side to an input side.

  Recent vehicles are widely equipped with an electric power steering device that drives a steering assist motor in response to an operation of a steering member such as a steering wheel and transmits the rotational force of the motor to a steering mechanism to assist steering. ing. Most of this type of electric power steering device is configured to include a speed reducer in the middle of the transmission system from the steering assist motor to the steering mechanism, and to reduce the rotation of the motor and transmit it to the steering mechanism. It is. The reduction gear device is provided for the purpose of compensating for the shortage of the output of the motor for assisting steering by an increase in force accompanying deceleration and obtaining a desired steering assist force by a small-sized and small capacity motor.

  In such an electric power steering device, in particular, an electric power steering device including a reduction gear, when the steering assist motor in a non-driven state rotates in conjunction with the operation of the steering mechanism, the inertia of the motor is reduced. Is added to the steering mechanism, causing a delay in the operation of the steering mechanism. For example, the neutral return to return to the straight traveling state after releasing the steering member is delayed. There is a problem that various problems occur.

  In order to solve this problem, a clutch device that is used in the middle of a transmission system from a steering assist motor to a steering mechanism has been proposed (for example, see Patent Document 1).

  The clutch device disclosed in Patent Document 1 includes a plurality of sprags that are equally arranged in an annular space between an outer ring and an inner shaft that rotate on the same axis, and an elastic member that maintains these in a neutral posture. Are connected to the input side (motor side) and the inner shaft is connected to the output side (steering mechanism side). The plurality of sprags can be tilted in the circumferential direction of the outer ring and the inner shaft around different axes, and in the neutral posture described above, one side is engaged with the inner circumferential surface of the outer ring, and the outer circumferential surface of the inner shaft is engaged. The other side is closely opposed.

  With the above configuration, when an input (positive input) is applied to the outer ring, each sprag is tilted by the action of the engaging portion with the outer ring, and the other side of each sprag whose position is changed by this tilting is on the outer peripheral surface of the inner shaft. The outer ring and the inner shaft are engaged by being pressed. Therefore, the positive input applied to the outer ring is transmitted to the inner shaft.

On the other hand, when an input (reverse input) is applied to the inner shaft, no force is applied to the sprags facing the outer periphery of the inner shaft, and each sprag maintains a neutral posture. Therefore, the reverse input applied to the inner shaft is blocked without being transmitted to the outer ring.
JP 2002-195306 A

  As described above, the clutch device disclosed in Patent Document 1 is engaged when a positive input is applied from the steering assisting motor side to the steering mechanism, and the reverse input from the steering mechanism side to the motor is performed. When functioning as a reverse input cutoff clutch that cuts off during operation and is applied to an electric power steering device, it prevents interlocking rotation of the steering assist motor due to reverse input from the steering mechanism side, and prevents inertia of the motor The problem that the steering feeling deteriorates due to the influence can be solved.

  However, in the reverse input cutoff clutch disclosed in Patent Document 1, since force transmission between the tilted sprag and the inner shaft is caused by friction in the pressing portion, particularly when the rotational force of the motor applied as input is large, There is a risk of slippage between the sprag and the inner shaft. Further, the generation of wear over time in the pressing portion between the sprag and the inner shaft is inevitable, and stable transmission can be continued for a long time. There is a problem that it is difficult.

  On the other hand, the force transmission between the outer ring and the sprag is not friction but is made through the teeth provided in the engaging portion, and these teeth are provided for tilting the sprag in accordance with the rotation of the outer ring. Since the number of teeth in the meshing state is limited, there is a problem that the magnitude of the rotational force that can be transmitted is limited.

  As described above, the reverse input cutoff clutch disclosed in Patent Document 1 can fulfill the function of blocking the transmission of the reverse input from the output side to the input side, but the transmission of the positive input from the input side to the output side is uncertain. In order to enable stable transmission of a large rotational force, the friction between the outer peripheral surface of the inner shaft and the sprag is increased, and the strength of the engaging portion between the outer ring and the sprag is increased. Measures such as these are necessary.

  The reverse input cut-off clutch that engages when the positive input is applied and cuts off when the reverse input is applied is not limited to the electric power steering device described above, but is required for various transmission systems that transmit the rotational force of the drive source to the load. Therefore, realization of a reverse input cut-off clutch that can surely transmit a large positive input is eagerly desired.

  The present invention has been made in view of such circumstances, and the transmission from the input side to the output side at the time of the engagement operation is performed without using the frictional transmission, so that the reverse input is reliably shut off and the large positive input is performed. An object of the present invention is to provide a reverse input shut-off clutch that realizes a stable transmission of the motor.

  The reverse input cut-off clutch according to the first aspect of the present invention is provided between an input rotating body and an output rotating body that rotate on the same axis, and is engaged by the action of a positive input from the input rotating body to the output rotating body. In a reverse input cut-off clutch that operates in combination and cuts off by the action of reverse input from the output rotator to the input rotator, the input rotator and the output rotator can move in the radial direction and rotate on the same axis. A movable element supported and opposed to the peripheral surface of the output rotator, urging means for urging the movable element in a direction away from the peripheral surface, and rotating in conjunction with the input rotator to the movable element Acting, moving the mover against the urging force of the urging means, and pressing the pressing member against the peripheral surface of the output rotator, and provided on the opposing surfaces of the output rotator and the mover, It is provided with the uneven part which mutually engages by pressing To.

  A reverse input cutoff clutch according to a second invention of the present invention is characterized in that a plurality of the movers in the first invention are arranged in parallel in the circumferential direction of the input rotating body and the output rotating body.

  The reverse input cutoff clutch according to the third aspect of the present invention is characterized in that the pressing elements in the first or second aspect are provided on both sides in the circumferential direction of the movable element.

  The reverse input cutoff clutch according to the fourth invention of the present invention is characterized in that the contact surfaces of the presser and the mover in the first to third inventions are inclined surfaces inclined with respect to the pressing direction. .

  Furthermore, the reverse input cutoff clutch according to the fifth aspect of the present invention is characterized in that the biasing means in the first to fourth aspects is an annular leaf spring.

  In the reverse input cutoff clutch according to the first aspect of the present invention, the pressing element acts on the movable element by the rotation of the input rotating body by the action of the positive input, and the movable element moves against the urging force of the urging means. And pressed against the output rotator to engage the concave and convex portions formed on the opposing surface. As a result, the positive input applied to the input rotator is transmitted to the output rotator without any friction via the mover held between the presser and the output rotator, and a large positive input is stabilized. Transmission can be realized together with reliable blocking of reverse input.

  In the reverse input cutoff clutch according to the second aspect of the present invention, the transmission described above is performed by a plurality of movers arranged in the circumferential direction, so that more reliable transmission can be performed.

  In the reverse input shut-off clutch according to the third aspect of the present invention, since the pressing elements are arranged on both sides of the mover, the above-described engaging / disengaging operation can be performed for the positive input in both directions, and the rotation direction is reversed. It can be applied to transmission systems including

  In the reverse input cutoff clutch according to the fourth aspect of the present invention, since the contact surface between the presser and the mover is an inclined surface, the pressing force of the mover by the presser is reinforced by the wedge action between these inclined surfaces. It is possible to firmly maintain the engagement with the output rotator and realize stable transmission.

  Furthermore, in the reverse input shut-off clutch according to the fifth aspect of the invention, since the annular leaf spring is used as the biasing means for biasing the mover, the leaf spring is opposed to the peripheral surface of the output rotating body to support the mover. The present invention has an excellent effect such that it can be used as a support and the configuration of the apparatus can be simplified.

  Hereinafter, the present invention will be described in detail with reference to the drawings illustrating embodiments thereof. FIG. 1 is a schematic diagram showing a configuration of an electric power steering apparatus including a reverse input cutoff clutch according to the present invention. The electric power steering apparatus shown in the figure includes a rack shaft 11 that is supported so as to be movable in the axial direction in a rack housing 10 that extends in the left-right direction of a vehicle body, and a pinion housing 12 that intersects the middle of the rack housing 10. And a pinion shaft 13 supported rotatably.

  Both ends of the rack shaft 11 projecting outward from both sides of the rack housing 10 are connected to the left and right front wheels 15 and 15 as steering wheels via separate tie rods 14 and 14, respectively, and the pinion projecting to the outside of the pinion housing 12 The upper end of the shaft 13 is connected to a steering wheel 17 as a steering member via a steering shaft 16. A pinion (not shown) is formed at the lower part of the pinion shaft 13 that extends into the pinion housing 12. The pinion is meshed with a rack that is provided in the middle of the rack shaft 11 at an intersection with the rack housing 10 to constitute a rack-and-pinion type steering mechanism 1.

  The steering shaft 16 is rotatably supported inside a cylindrical column housing 18, and is attached via the column housing 18 to the interior of a passenger compartment (not shown) while maintaining an inclined posture with the front facing down. A pinion shaft 13 is connected to a downward projecting end of the column housing 18, and a steering wheel 17 is fixed to the upward projecting end.

  With the above configuration, when the steering wheel 17 is rotated for steering, this rotation is transmitted to the pinion shaft 13 through the steering shaft 16, and the axial direction of the rack shaft 11 is in the meshing portion between the pinion and the rack. Converted to move. The movement of the rack shaft 11 thus generated is transmitted to the left and right front wheels 15 and 15 via the respective tie rods 14 and 14 for steering.

  A torque sensor 2 for detecting a steering torque applied to the steering shaft 16 by the rotation operation of the steering wheel 17 is provided in the middle of the column housing 18 that supports the steering shaft 16, and outside the lower end portion of the column housing 18. Is attached with a motor 3 for assisting steering.

  The torque sensor 2 divides the steering shaft 16 to be detected into two upper and lower axes, and these two axes are connected on the same axis by a torsion bar having a known torsion characteristic, and the torsion bar is twisted by the action of the steering torque. With this, there is a known configuration for detecting the relative angular displacement generated between the two axes by an appropriate means.

  On the output side of the steering assisting motor 3, a reverse input shut-off clutch 4 according to the present invention, which is configured as will be described later, is provided in parallel, and these have an axial center substantially orthogonal to the outside of the column housing 18. Attached. A reduction gear 19 such as a worm gear reduction gear is provided in the column housing 18 so as to correspond to the mounting portions of the motor 3 and the reverse input cutoff clutch 4, and the rotation of the steering assist motor 3 is described later. The reverse input cutoff clutch 4 that engages as described above is taken out to the output side, decelerated by the reduction gear 19 and transmitted to the steering shaft 16. With this configuration, the output of the steering assisting motor 3 is transmitted to the pinion shaft 13 connected to the lower end of the steering shaft 16, and is performed as described above by the operation of the steering mechanism 1 in accordance with the rotation of the pinion shaft 13. Steering is assisted.

  The steering assist motor 3 is driven in accordance with a control command given from the assist control unit 30 to a drive circuit (not shown). The assist control unit 30 is given a detected value of the steering torque by the torque sensor 2, and the assist control unit 30 applies the steering torque given from the torque sensor 2 to a predetermined control map to obtain the target assist force. In order to generate the target assist force, a control command is issued to the steering assist motor 3, and a known assist control operation for driving and controlling the motor 3 is performed.

  A plurality of control maps used for determining the target assist force are prepared according to the vehicle speed, and are selected and used according to the detection result of the vehicle speed taken from a vehicle speed sensor (not shown). As a result, the assist force characteristics are made different according to the level of the vehicle speed. For example, when the road surface reaction force applied to the front wheels 15 and 15 is small, the steering assist force generated by the motor 3 is kept low, and the steering wheel 17 is rigid. It is possible to give a sense of nature and to perform stable steering without wobbling. Conversely, when the road surface reaction force is large and the vehicle is running at low speed, the steering assist force is increased as much as possible to lightly operate the steering wheel 17 and reduce the labor burden required for steering. Regardless of this, an appropriate steering state can always be obtained.

  The reverse input cutoff clutch 4 provided in parallel with the steering assisting motor 3 is engaged when a force (positive input) from the motor 3 is applied, and an action of the force (reverse input) from the steering mechanism 1 side. The clutch means is sometimes configured to be shut off. 2 is a cross-sectional view of the reverse input cutoff clutch 4 taken along the line II-II in FIG. 1, and FIG. 3 is an exploded perspective view of the reverse input cutoff clutch 4.

  As shown in FIGS. 2 and 3, the reverse input cutoff clutch 4 includes an input disk (input rotator) 5 and an output disk (output rotator) 6, and a pair of movers 7 and 7 disposed therebetween. And. The input disk 5 is connected to the input side, that is, the steering assisting motor 3 through a coaxially connected shaft 50, and is configured to rotate by transmission from the motor 3. On the end face of the input disk 5, two support bars 51, 51 are projected at positions in the radial direction near the periphery, and a pair of presses are provided on both sides of the support bars 51, 51. The children 52 and 52 are projected.

  The output disk 6 having a smaller diameter than the input disk 5 is supported so as to be rotatable coaxially with the input disk 5, and is connected to the output side, that is, a steering mechanism via a shaft 60 provided coaxially. 1 is connected to a speed reducer 19 for speed reduction transmission to 1. On the outer peripheral surface of the output disk 6, an uneven portion 61 is formed over the entire periphery.

  As shown in FIG. 3, the pair of movers 7, 7 has a mountain-shaped cross-sectional shape, is a block that is substantially equal in thickness to the output disk 6, and is formed on both sides in the thickness direction by the pair of leaf springs 8, 8. It is supported from. FIG. 4 is an enlarged perspective view showing a support structure for the movers 7 and 7. As shown in the figure, the movers 7 and 7 are provided with recesses 70 and 71 having appropriate widths at the centers of the top surface and the bottom surface, and the output disks are provided on the bottom surfaces of the movers 7 on both sides of the recess 71. An uneven portion 72 that can be engaged with the 6 uneven portions 61 is formed. In addition, a presser piece 73 having an appropriate width that bends in the shape of a bowl with the bottom side recessed is projected at the center of the end face of the mover 7. Both sides of the presser piece 73 are formed to penetrate in the thickness direction. The small-diameter support holes 74 are arranged in a distributed manner.

  As shown in FIGS. 3 and 4, the leaf springs 8, 8 are provided with through holes 80, 80 at two locations opposed to each other in the radial direction, and both end portions are fitted into the through holes 80, 80, respectively. The rod-like holding bodies 81 and 81 are integrally held at an appropriate interval. As shown in FIG. 3, both ends of the cages 81, 81 protruding from the through holes 80, 80 are fitted and supported by plate-like carriers 82, 82 arranged outside the plate springs 8, 8. The carriers 82 and 82 are provided to support both sides of the cages 81 and 81 at the same position and to restrain the relative movement in the circumferential direction of the leaf springs 8 and 8 held by these cages 81 and 81. ing.

  In addition, a pair of support rods 83, 83 projecting toward the opposite sides of the plate springs 8, 8 are arranged in a distributed manner between the positions where the through holes 80, 80 are formed. The distribution interval of each pair of support rods 83, 83 is made to coincide with the distribution interval of the support holes 74, 74 provided in the movers 7, 7.

  The movable elements 7 and 7 are supported by the leaf springs 8 and 8 by arranging the movable elements 7 and 7 between the leaf springs 8 and 8 with the respective bottom surfaces provided with the concavo-convex portions 72 facing inward. As shown by the arrows in FIG. 2, the support rods 83 and 83 corresponding to the support holes 74 and 74 of both the movable elements 7 and 7 are inserted, and the leaf spring is inserted into the recess of the presser piece 73 located between the support holes 74 and 74. This is realized by fitting 8,8.

  The movers 7 and 7 supported in this way are positioned outside the output disc 6 while maintaining the circumferential position shown in FIG. 3, and annular leaf springs 8 and 8 and a carrier 82 are provided from both sides of the output disc 6. , 82 are supported and assembled as described above. As shown in FIG. 2, the movable elements 7, 7 are positioned between the pressing elements 52, 52 projecting from the end face of the input disk 5 on the circumference of the leaf springs 8, 8, as shown in FIG. Each bottom surface provided with 72 is brought into close proximity to the outer peripheral surface of the output disk 6.

  Recesses 71, 71 provided on the top surfaces of the movable elements 7, 7 are in contact with support rods 51, 51 located between the pressing elements 52, 52 and projecting from the end face of the input disk 5. The outward movement of the movers 7 and 7 due to the urging of the leaf springs 8 and 8 is suppressed, and the movers 7 and 7 are positioned at the neutral position shown in FIG. At this time, the bottom surfaces of the movers 7 and 7 are in a state of facing each other with an appropriate gap between them and the outer peripheral surface of the output disk 6.

  The end faces of the pressers 52, 52 located on both sides of the movers 7, 7 are tapered surfaces that expand inward to align with the inclined surfaces of the movers 7, 7 having a mountain shape, and in the neutral state shown in FIG. 7 and 7 are closely opposed to each other. As shown in FIG. 2, the retainers 81, 81 of the leaf springs 8, 8 are provided at positions that do not interfere with the pressers 52, 52 protruding from the input disk 5 on the same circumference.

  2 in FIG. 2 is a cylindrical outer case, and the reverse input shut-off clutch 4 is provided on the outer side of the input disk 5, the output disk 6 and the movers 7, 7 assembled as shown in FIG. The case 9 is covered.

  FIG. 5 is a diagram for explaining the operation of the reverse input cutoff clutch 4 configured as described above. The input disk 5 and the output disk 6 and the mover 7 arranged between them are shown in a straight line. is there.

  FIG. 5A shows the assembled state, and the movable element 7 is pushed outward (upward in the figure) by the action of the urging force of the leaf spring 8, and as described above, the recess 71 on the top surface is shown. A gap Δt is maintained between the bottom surface of the mover 7 provided with the concavo-convex portion 72 and the outer peripheral surface of the output disc 6 provided with the concavo-convex portion 61. Have opposites.

  Therefore, as indicated by an arrow in the figure, when a circumferential rotational force is applied to the output disk 6, this rotational force is not transmitted to the movable element 7 and the input disk 5, and the movable element 7 is in a neutral state. The input disk 5 is maintained in a non-rotating state. Therefore, the reverse input from the steering mechanism 1 to which the output disk 6 is connected can be blocked without being transmitted to the motor 3 to which the input disk 5 is connected, and the inertia of the motor 3 in the non-driven state can be prevented. An excellent steering feeling can be realized by eliminating the influence on steering.

  FIG. 5B and FIG. 5C show a state in which a rotational force is applied to the input disk 5 connected to the motor 3. In this case, the pressers 52 and 52 projecting from the input disk 5 move in the respective rotation directions as indicated by white arrows in the figure, and are located on the upstream side in the rotation direction. Abuts against the movable element 7 and presses the movable element 7 in the circumferential direction. Since the mover 7 has a mountain-shaped cross section as described above, and the pressing element 52 presses the slope of the mountain shape as shown in the figure, a component force that is radially inward (downward in the drawing) is applied to the mover 7. .

  As described above, the movable element 7 is supported by the annular leaf spring 8, and the movable element 7 pressed by the pressing element 52 moves in the radial direction with the deformation of the leaf spring 8. By this movement, as shown in the figure, the support side of the support bar 83 on the pressing side by the pressing element 52 is pushed down among the support bars 83 and 83 that protrude from the leaf spring 8 and support the movable element 7, and the bottom surface on the same side The concavo-convex portion 72 formed on the outer peripheral portion engages with the concavo-convex portion 61 on the peripheral surface of the output disc 6, and the rotation of the input disc 5 is transmitted to the output disc 6 via the pressing element 52 and the movable element 7. As a result, the output disk 6 rotates in the same direction as the input disk 5 as indicated by white arrows in FIGS. 5 (b) and 5 (c).

  Note that the support side of the movable element 7 supported by the other support bar 83 jumps up due to the reaction of the pusher 52 being pushed down, but this jumping up is suppressed by the action of the support bar 51 in contact with the recess 70, A stable push-down posture is maintained with the bending deformation of the leaf spring 8 as shown.

  In this transmission state, the mover 7 is pressed in the rotational direction by the pressing element 52 and pressed against the output disc 6 and is held between the two. The mover 7 and the output disc 6 are respectively connected to each other. Engaged by the uneven portions 72 and 61. Therefore, the transmission from the input disk 5 to the output disk 6 is performed without any friction, and a reliable transmission without slipping can be realized.

  The end face of the pressing element 52 that comes into contact with the movable element 7 is a tapered surface corresponding to the slopes on both sides of the movable element 7, and the depression of the movable element 7 shown in FIGS. 5 (b) and 5 (c) 7 and the end face of the pressing element 52 are firmly maintained by the wedge action, so that a large load of rotational force can be reliably transmitted.

  When the application of the rotational force to the input disk 5 is released, the mover 7 is displaced outward by the elastic return of the leaf spring 8 and returns to the neutral state shown in FIG. In this case, as described above, transmission of the reverse input from the output disk 6 to the input disk 5 can be blocked.

  The shapes of the input disk 5 as the input rotator, the output disk 6 as the output rotator, and the mover 7 and the positional relationships thereof are not limited to the configurations shown in the above-described embodiments, and appropriate configurations. Can be realized.

  In the above embodiment, the annular leaf spring 8 is used as the biasing means for biasing the movers 7 and 7 away from the peripheral surface of the fixed disk 6. It is also possible to use a biasing means. However, the leaf spring 8 shown in the embodiment can also serve as a support for the movers 7 and 7 and can contribute to the simplification of the device configuration.

  Furthermore, although the above embodiment demonstrated the case where it applied to the transmission system from the motor 3 for steering assistance to the steering mechanism 1 in an electric power steering device, the reverse input interruption | blocking clutch 4 which concerns on this invention is The present invention can be applied to all types of transmission systems that require blocking of the reverse input, and an effect that a positive input can be reliably transmitted without slipping is obtained.

It is a mimetic diagram showing composition of an electric power steering device provided with a reverse input interception clutch concerning the present invention. It is a cross-sectional view of the reverse input cutoff clutch by the II-II line of FIG. It is a disassembled perspective view of a reverse input interruption | blocking clutch. It is an expansion perspective view which shows the support structure of a needle | mover. It is operation | movement explanatory drawing of the reverse input interruption | blocking clutch which concerns on this invention.

Explanation of symbols

  4 reverse input cutoff clutch, 5 input disk (input rotator), 6 output disk (output rotator), 7 mover, 8 leaf spring (biasing means), 52 presser, 61, 72 uneven parts

Claims (5)

It is provided between the input rotator and the output rotator that rotate on the same axis, engages by the action of the positive input from the input rotator to the output rotator, and reverses from the output rotator to the input rotator. In the reverse input cutoff clutch that shuts off by the action of input,
A movable element supported to enable radial movement and coaxial rotation of the input rotator and the output rotator, and facing a circumferential surface of the output rotator;
Biasing means for biasing the mover in a direction away from the peripheral surface;
A pressing element that rotates in conjunction with the input rotator, acts on the mover, moves the mover against the urging force of the urging means, and presses against the peripheral surface of the output rotator;
A reverse input cutoff clutch, comprising: an uneven portion provided on opposing surfaces of the output rotator and the mover and engaged with each other by the pressing.   The reverse input blocking clutch according to claim 1, wherein a plurality of the movers are arranged in parallel in a circumferential direction of the input rotator and the output rotator.   The reverse input blocking clutch according to claim 1 or 2, wherein the pressing elements are provided on both sides of the movable element in the circumferential direction.   4. The reverse input cutoff clutch according to claim 1, wherein contact surfaces of the pressing element and the movable element are inclined surfaces inclined with respect to the pressing direction. 5.   The reverse input cutoff clutch according to any one of claims 1 to 4, wherein the biasing means is an annular leaf spring.

Images