JP6001312B2 - Shaft coupling mechanism - Google Patents

Description

  The present invention relates to a shaft coupling mechanism suitable for coupling a rotation shaft on a rotation source side such as an electric motor in an electric power steering device and a rotation shaft on an operation side such as a steering shaft of an automobile.

  For example, an electric motor that can easily perform manual steering of a steering wheel by adding a rotational force based on the rotation of an output rotation shaft of an electric motor to a rotational force based on rotation of a steering wheel (handle) that is manually operated. In the power steering apparatus, the steering shaft on the steering wheel side and the rotating shaft on the output rotating shaft side of the electric motor are usually connected via a worm gear and a shaft connecting mechanism (coupling).

JP 2002-274395 A JP 2003-95118 A

  In such an electric power steering device, when the steering shaft and the rotating shaft are connected via a rigid shaft connecting mechanism, the impact when the output rotating shaft of the electric motor is reversed, the brush vibration of the electric motor is the shaft connecting mechanism, It may be transmitted to the steering wheel via the worm gear, the worm wheel and the steering shaft to cause an unpleasant steering feeling to the driver, and may cause abnormal noise and vibration due to backlash of the worm gear. In order to avoid this, it has been proposed to interpose an elastic body in the shaft coupling mechanism. However, if the elastic body is made more flexible by placing emphasis on the reduction of impact and vibration, flexible elasticity Since the body is prone to creep deformation, the elastic deformation of the elastic body due to repeated loads on the elastic body causes backlash in the shaft coupling mechanism, On the other hand, there is a risk that the driver's steering feeling may become unpleasant. On the other hand, if the spacer is made harder with an emphasis on durability, the steering feeling is improved in terms of no play, but as described above. In addition to making the steering feel uncomfortable due to the impact and vibration transmitted to the steering wheel, it is not possible to reduce abnormal noise and vibration caused by backlash of the worm gear.

  In Patent Document 2, a rotation transmission member having elasticity is interposed between a rotation transmission member and a worm shaft to reduce collision noise (rattle noise) between tooth surfaces caused by backlash and a steering wheel. In this shaft coupling mechanism, an elastic rotation transmission member is used in the rotational direction in addition to the axial compressive deformation in this shaft coupling mechanism. Therefore, there is a possibility that it will deteriorate early due to repeated torsional deformation.

  The present invention has been made in view of the above-described points, and an object of the present invention is to prevent the elastic body from undergoing elastic torsional deformation in the rotation direction, for example, when the output rotation shaft of the electric motor is reversed. Noise, vibration and vibration caused by backlash of the worm gear, transmission of brush vibration of the electric motor to the steering wheel, and vibration can be reduced, and the driver's steering feeling can be improved. The object is to provide a shaft coupling mechanism that can be avoided.

  The shaft coupling of the present invention is arranged between the first and second rotating shafts so as to transmit the rotations of the first and second rotating shafts to each other and connects the first and second rotating shafts to each other. The mechanism is rotated by rotation of the first rotation shaft, while the first connection base connected to the first rotation shaft so as to rotate the first rotation shaft by rotation, and the second rotation shaft A second connecting base coupled to the second rotating shaft so as to rotate the second rotating shaft by rotation while rotating between the first connecting base and the first rotating shaft in the axial direction; Defined between at least one of the second connecting base and the second rotating shaft in the axial direction and having a variable length in the axial direction, and the first and second rotating shafts One of the first and second connecting bases that define the gap with one of the rotating shafts After the connecting base moves by a predetermined amount in the axial direction to reduce the axial length of the gap with respect to the one rotating shaft, the one connecting base is moved in the axial direction relative to the one rotating shaft. After the contact surface that contacts the one rotating shaft and the one connecting base move in a predetermined amount in the axial direction to reduce the axial length of the gap with respect to the one rotating shaft so that they do not move, At least one of the contact surfaces that contact the one rotation shaft so that the other connection substrate of the first and second connection substrates does not move in the rotation direction relative to the one rotation shaft. The first connecting base is rotated by the rotation of the first rotating shaft, while the first rotating shaft is rotated by the rotation. The first base coupled to the first rotating shaft and At least one pair of first cam surfaces that are formed on one axial surface of the base portion and are inclined in opposite directions in the rotational direction. Formed on one surface in the axial direction of the second base and the second base connected to the second rotational shaft so as to rotate the second rotational shaft by rotation while rotating by the rotation of the shaft And having a shape complementary to the at least one pair of first cam surfaces and inclined in directions opposite to each other in the rotation direction, and the rotation direction with respect to the at least one pair of first cam surfaces A pair of second cam surfaces that are relatively slidably in contact with each other, and the one connection base is relative to the pair of second cam surfaces with respect to the pair of first cam surfaces. Connected to the at least one connecting base by sliding movement. In relation to at least one of the first and second rotating shafts to move in the axial direction with respect to at least one of the rotating shafts to increase or decrease the axial length of the gap. The elastic member is movably connected in the axial direction, and the elastic member is disposed in the gap so as to be elastically expanded and contracted by increasing or decreasing the axial length of the gap.

  According to the shaft coupling mechanism of the present invention, the first coupling base includes at least a pair of first cam surfaces inclined in directions opposite to each other in the rotation direction, and the second coupling base includes at least a pair of pairs. A pair of second cam surfaces that are in contact with the first cam surface so as to be relatively slidable in the rotational direction, and at least one of the first and second connection bases is a pair Relative to at least one of the first and second rotating shafts connected to the at least first connecting base by the relative sliding movement of the pair of second cam surfaces with respect to the first cam surface In order to move in the axial direction and cause an increase or decrease in the axial length of the gap, the elastic member is movably connected in the axial direction with respect to the at least one rotating shaft. Elastically expands and contracts by increasing or decreasing the axial length of the gap As described above, since the second connecting base is slightly rotated relative to the first connecting base, the pair of second cam faces is paired with the first connecting base. As a result of the sliding movement, the axial length of the gap is reduced by this sliding movement, and the elastic member is contracted in the axial direction by the reduction of the length. The relative rotation is absorbed by the shortening of the elastic member in the axial direction and is not transmitted to the second connection base, and thus, for example, the first rotation that causes a minute rotation of the first connection base. In addition to reducing the impact when the output rotation shaft of the electric motor connected to the rotation shaft is reversed, the transmission of the brush vibration of the electric motor to the steering wheel through the second connection base, for example, the second rotation Worm gear (worm shaft) connected to the shaft and the The vibration caused by the backlash between the worm wheel and the worm wheel connected to the steering shaft can be absorbed by the expansion and contraction of the elastic member in the axial direction, eliminating the occurrence of noise such as rattling in the worm gear and worm wheel. Thus, the steering feeling of the driver can be improved, and the length of the gap in the axial direction is reduced by a predetermined amount or more due to the relative rotation of the first connection base with respect to the second connection base over a predetermined amount. Is reduced in the axial direction by a predetermined amount or more, at least one of the one connection base and the other connection base is axially moved relative to the one rotation shaft by the contact of the contact surface with the one rotation shaft. As a result, the sliding movement of the pair of second cam surfaces with respect to the pair of first cam surfaces does not occur. For example, the rotation of the first connection base is transmitted to the second connection base, and the second connection base As a result, the rotation of the rotation output shaft of the electric motor connected to the first rotation shaft is transmitted through the worm gear connected to the second rotation shaft. It is transmitted to the worm wheel that meshes with the worm gear, and the steering shaft is also rotated by the rotation of the worm wheel, so that it is possible to assist the manual steering of the steering wheel connected to the steering shaft, and in the axial direction. As a result of the sliding movement of the pair of second cam surfaces with respect to the pair of first cam surfaces without causing elastic shearing deformation (twisting deformation) in the rotational direction to the elastic member that expands and contracts, early deterioration of the elastic member is caused. It can be avoided and the durability can be improved.

  In the present invention, the first connection base has a fitting recess formed in the first base portion and a fitting protrusion formed integrally with the axial end portion of the first rotating shaft. The rotation of one of the first connecting base and the first rotating shaft via the fitting protrusion fitted in the fitting recess is the first connecting base and the first rotating shaft. In addition to or instead of this, the first connecting base is a fitting formed at the axial end of the first rotating shaft. The first connecting base has a fitting protrusion integrally formed on the first base portion and fitted into the fitting recess, and the fitting base is formed through the fitting protrusion fitted in the fitting recess. And the rotation of one of the first rotating shafts may be transmitted to the other of the first connecting base and the first rotating shaft.

  In the present invention, the second connection base has a fitting recess formed in the second base portion and a fitting protrusion formed integrally with the axial end of the second rotating shaft. And the rotation of one of the second connecting base and the second rotating shaft via the fitting protrusion fitted in the fitting recess is the second connecting base and the second rotating base. The second connection base is a fitting formed at the end of the second rotation shaft in the axial direction even if it is transmitted to the other of the rotation shafts of the second rotation shaft. The fitting base has a fitting protrusion that is integrally formed with the second base portion and fits into the fitting recess, and the second connecting base via the fitting protrusion fitted into the fitting recess. And the rotation of one of the second rotation shafts may be transmitted to the other of the second coupling base and the second rotation shaft.

  In the shaft coupling mechanism of the present invention, the pair of first cam surfaces and the pair of second cam surfaces that are slidably contacted with each other are relatively rotated with respect to the first base portion. In this case, the second base portion may be relatively axially separated from the first base portion by sliding relative to the elastic force of the elastic member. The relative axial separation distance of the second base with respect to the one base includes the inclination angle of the first cam surface and the second cam surface, and the relative rotation amount of the second base with respect to the first base. You may depend on.

  In a preferred example of the shaft coupling mechanism of the present invention, the pair of first cam surfaces are arranged with a first flat surface intersecting the axial direction in the rotational direction, and the pair of second cam surfaces The surface is arranged with a second flat surface intersecting the axial direction in the rotational direction. In such an example, the mechanical strength of the cam surface can be maintained, and deformation of the cam surface can be prevented. .

  In the shaft coupling mechanism of the present invention, the first base is connected to the first rotation shaft so as to be relatively movable in the axial direction, while the second base is configured to be the second rotation shaft. In this case, the elastic member is a gap having a variable length in the axial direction between the first connecting base and the first rotating shaft in the axial direction. Instead of these, instead of these, the first base is adapted to be immovably connected to the first rotating shaft in the axial direction, while the second base is The second rotary shaft may be connected to the second rotary shaft so as to be relatively movable in the axial direction. In this case, the elastic member is an axial direction between the second connecting base and the second rotary shaft in the axial direction. It is good to be arranged in a gap with a variable length.

  In the present invention, the first base may be connected to the first rotation shaft and the second base may be connected to the second rotation shaft so as to be freely movable in the axial direction. The shaft coupling mechanism of the present invention includes two elastic members, and one elastic member is a gap in which the axial length between the first coupling base and the first rotation shaft in the axial direction is variable. The other elastic member is arranged in a gap in which the length in the axial direction between the second connecting base and the second rotating shaft in the axial direction is variable. Good.

  In a preferred example, the elastic member causes the second base portion to approach the axial direction relative to the first base portion due to its elastic force.

  In the present invention, as long as the early deterioration of the elastic member can be prevented, the first connection base through the contact of the contact surface to one of the rotating shafts with the compression of the elastic member not exceeding a predetermined amount Prior to the mutual transmission of the rotation with the second connection base, the rotations of the first connection base and the second connection base may be transmitted to each other via the elastic member. .

  The shaft coupling mechanism of the present invention may be for an electric power steering device. In this case, the first rotating shaft is coupled to the output rotating shaft of the electric motor. The rotary shaft may be connected to the steering shaft of the automobile via a worm gear and a worm wheel that mesh with each other.

  According to the present invention, without causing elastic torsional deformation in the rotational direction to the elastic body, for example, the impact when the output rotation shaft of the electric motor is reversed, the transmission of brush vibration of the electric motor to the steering wheel, and the worm gear It is possible to provide a shaft coupling mechanism that can reduce abnormal noise such as rattling caused by backlash and vibration, improve the steering feeling of the driver, and avoid early deterioration.

FIG. 1 is a partial cross-sectional explanatory view of a preferred example of an embodiment of the present invention. FIG. 2 is an explanatory side view of the first connecting base in the example shown in FIG. FIG. 3 is an explanatory front view of the connection base shown in FIG. FIG. 4 is an explanatory view of the back surface of the connection base shown in FIG. FIG. 5 is a cross-sectional explanatory view taken along line VV shown in FIG. FIG. 6 is an explanatory side view of the second connecting base in the example shown in FIG. FIG. 7 is an explanatory front view of the connecting base body shown in FIG. FIG. 8 is an explanatory rear view of the connection base shown in FIG. FIG. 9 is a cross-sectional explanatory view taken along line IX-IX in FIG. FIG. 10 is an explanatory side view of the first rotating shaft in the example shown in FIG. 1. FIG. 11 is an explanatory front view of the rotating shaft shown in FIG. FIG. 12 is a partially broken side view of the second rotating shaft in the example shown in FIG. FIG. 13 is an explanatory front view of the rotating shaft shown in FIG. 2. 14 is an explanatory cross-sectional view taken along line XIV-XIV shown in FIG. FIG. 15 is a perspective explanatory view of the elastic member of the example shown in FIG. FIG. 16 is an explanatory rear view in which the connecting base shown in FIG. 6 and the elastic member shown in FIG. 15 are combined. 17 is a cross-sectional explanatory view taken along line XVII-XVII shown in FIG. FIG. 18 is a diagram for explaining the operation of the example shown in FIG. FIG. 19 is a cross-sectional explanatory view taken along line XIX-XIX shown in FIG. FIG. 20 is a partial cross-sectional explanatory diagram of another preferable example of the embodiment of the present invention. FIG. 21 is an explanatory side view of the first connecting base in the example shown in FIG. 22 is an explanatory front view of the connecting base body shown in FIG. FIG. 23 is an explanatory side view of the second connecting base in the example shown in FIG. 24 is an explanatory front view of the connecting base body shown in FIG. FIG. 25 is an explanatory view of the back surface of the connection base shown in FIG. FIG. 26 is a perspective explanatory view of the elastic member of the example shown in FIG. FIG. 27 is a perspective explanatory view of the second rotating shaft of the example shown in FIG.

  Next, embodiments of the present invention will be described in more detail based on preferred examples shown in the drawings. The present invention is not limited to these examples.

  1 to 17, the rotary shaft 2 and the rotary shaft 2 so as to transmit the rotation in the R direction around the axis O of the rotary shaft 2 on the electric motor side and the rotary shaft 3 on the worm shaft side of the electric power steering device. The shaft coupling mechanism 1 for the electric power steering apparatus of this example, which is arranged between 3 and couples the rotating shafts 2 and 3 to each other, is rotated in the same direction by the rotation of the rotating shaft 2 in the R direction. On the other hand, the connecting base 4 connected to the rotating shaft 2 so as to rotate the rotating shaft 2 in the same direction by the rotation in the R direction and the rotating base 3 are rotated in the same direction by the rotation in the R direction. The connection base 5 connected to the rotation shaft 3 so as to rotate the rotation shaft 3 in the same direction by rotation, and the connection base 4 and the rotation shaft 3 in the A direction which is the axial direction, and the connection base 5 and the rotation shaft in the A direction. At least one of the three , In this example it is provided with an elastic member 7 that the length L in the A direction between connecting base 5 and the rotary shaft 3 is arranged in the variable gap 6.

  On the end surface 12 of the end portion 11 of the rotating shaft 2 in the A direction, as shown in FIGS. 10 and 11, a fitting protrusion 13 protruding in the A direction from the end surface 12 is integrally formed. The joint protrusion 13 includes three protrusions 14 that are spaced apart at equal angular intervals in the R direction and are integrally formed extending in the radial direction.

  As shown in FIGS. 12 and 13 in particular, an end 15 in the A direction of the rotary shaft 3 is formed with a bottomed recess 17 opened at the end surface 16 of the end 15. The small-diameter arcuate inner peripheral surface 18, three large-diameter arc inner peripheral surfaces 20 formed at equal angular intervals in the R direction across the small-diameter arcuate inner peripheral surface 18 in the R direction, One edge portion 27 in the R direction of each peripheral surface 20 is connected to the small-diameter arc inner peripheral surface 18 and one flat inner side surface 25 extending radially from the axis O in the radial direction, and the large-diameter arc inner peripheral surface 20. The other edge portion 28 in the R direction is connected to the small-diameter arc inner peripheral surface 18 and is defined by the other flat inner side surface 26 and the circular inner bottom surface 21 extending radially from the axis O in the radial direction. Thus, the recess 17 has a cylindrical recess portion 23 and a radial outer edge of the recess portion 23 in the R direction. It is provided with an arcuate three recesses 24 spaced with equal angular intervals.

  As shown in FIGS. 2 to 5, the connecting base 4 is rotated in the same direction by the rotation of the rotating shaft 2 in the R direction, while rotating so that the rotating shaft 2 is rotated in the same direction by the rotation in the R direction. A base 31 connected to the shaft 2 and three pairs of cam surfaces 33 and 34 that are integrally formed on one surface 32 in the A direction of the base 31 and are inclined in opposite directions in the R direction. ing.

  The base portion 31 has a shape complementary to the fitting protrusion 13 and has a cylindrical portion 43 having a fitting recess 42 opened at one surface 41 in the A direction, and a cylindrical outer periphery in the radial direction of the cylindrical portion 43. Three arc-shaped radial protrusions 45 formed integrally with the surface 44 and spaced apart at equal angular intervals in the R direction and projecting in the radial direction, and A of the cylindrical portion 43 and the radial protrusion 45 Three arc-shaped axially projecting portions 47 that are formed integrally with one end face 46 in the direction and project in the A direction and spaced apart at equal angular intervals in the R direction. Each of the cam surfaces 33 and 34 is formed on an end surface in the A direction of each of the three axial protrusions 47.

  A fitting protrusion 13 formed integrally with the end 11 in the A direction of the rotating shaft 2 is fitted in the fitting recess 42 of the cylindrical portion 43, and is fitted into the fitting recess 42. The rotation in the R direction in one of the connection base 4 and the rotation shaft 2 is transmitted to the other of the connection base 4 and the rotation shaft 2 through the fitting protrusion 13.

  The cylindrical portion 43 is disposed in the cylindrical recess portion 23 so as to be movable in the A direction, and three outer peripheral surfaces of the circular arc exposed at an equal angular interval in the R direction on the outer peripheral surface 44 of the cylindrical portion 43. Are slidably in contact with each of the small-diameter arc inner peripheral surface 18 of the rotating shaft 3. Each of the radial protrusions 45 is disposed in each of the recesses 24, and each of the arc outer peripheral surfaces 39 extending in the direction around the axial center of the radial protrusion 45 is a large-diameter arc inner peripheral surface 20. Are slidably in contact with each other.

  The length of the arcuate three radial protrusions 45 in the R direction is shorter than the length of the arcuate three recesses 24 in the R direction, and the diameter extends radially from the axis O in the radial direction. In the outer flat surfaces 35 and 36 in the R direction of the direction protrusion 45, for example, as shown in FIG. 14, the outer surface 35 is arranged with a gap 37 in the R direction with respect to the inner surface 25. Is arranged with a gap 38 in the R direction with respect to the inner surface 26. The widths of the gaps 37 and 38 in the R direction increase and decrease in the R direction relative to the rotation axis 3 of the coupling base 4. For example, in the state where the outer surface 36 is in contact with the inner surface 26 as shown in FIG. While the width of the gap 38 is zero, the width of the gap 37 is the maximum width D. Although not shown, the width of the gap 38 is the maximum width D when the outer surface 35 is in contact with the inner surface 25. On the other hand, the width of the gap 37 is zero. When the outer side surface 35 is in contact with the inner side surface 25 or the outer side surface 36 is in contact with the inner side surface 26, the rotation of one of the connecting base 4 and the rotating shaft 3 in the R direction is not connected via the connecting base 5. It is transmitted directly to the other of the base 4 and the rotary shaft 3. Each of the inner side surfaces 25 and 26 and the outer side surfaces 35 and 36 as contact surfaces functions as a rigid rotation transmission surface.

  As shown in FIGS. 6 to 9, the connecting base 5 is rotated in the same direction by the rotation of the rotation shaft 3 in the R direction, while rotating so that the rotation shaft 3 is rotated in the same direction by the rotation in the R direction. A base 51 connected to the shaft 3 and one surface 52 in the A direction of the base 51 are integrally formed, and are inclined in opposite directions in the R direction to be complementary to the cam surfaces 33 and 34, respectively. The three cam surfaces 53 and 54 have a shape and are in contact with the cam surfaces 33 and 34 so as to be relatively slidable in the R direction.

  The base 51 that is movably fitted in the recess 17 of the rotary shaft 3 has a shape complementary to the recess 23 and is closed by one surface 52 in the A direction. The cylindrical portion 63 having a bottomed recess 62 opened on the other surface 55 in the A direction and the cylindrical outer peripheral surface 64 in the radial direction of the cylindrical portion 63 are integrally formed. Three arc-shaped radial protrusions 65 projecting in the radial direction and spaced apart at equal angular intervals in the R direction, and one end surface 66 in the A direction of the cylindrical part 63 and the radial projection 65 are integrally formed. And three arc-shaped axial protrusions 67 projecting in the A direction and spaced apart at equal angular intervals in the R direction, and each of the three pairs of cam surfaces 53 and 54 includes three Each of the axial protrusions 67 is formed on an end surface in the A direction.

  The base 51 is fitted to the rotary shaft 3 slidably in the A direction with a gap 6 in the A direction between the surface 55 and the circular inner bottom surface 21 of the rotary shaft 3.

  The cylindrical portion 63 is disposed in the cylindrical recess 23 so as to be movable in the A direction, and the outer peripheral surface 64 of the cylindrical portion 63 is slidable in the A direction on the small-diameter arc inner peripheral surface 68 of the rotary shaft 3. Is in contact with Each of the radial protrusions 65 is disposed in each of the recesses 24, and the arc outer peripheral surface 69 extending in the direction around the axial center of the radial protrusion 65 is formed on the large-diameter arc inner peripheral surface 70. It is slidable in the direction.

  The length of the arcuate three radial protrusions 65 in the R direction is equal to the length of the arcuate three recesses 24 in the R direction and extends radially from the axis O in the radial direction. In the side surfaces 75 and 76 that are flat rigid rotation transmission surfaces in the R direction of the protrusion 65, the side surface 75 is slidably in contact with the inner side surface 25 in the A direction, and the side surface 76 is in contact with the inner side surface 26 in the A direction. Is slidably in contact with. In this way, the connecting base body 5 fitted to the rotary shaft 3 so as to be slidable in the A direction has the side surfaces 75 and 76 in contact with the inner side surfaces 25 and 26, so that the R direction is relative to the rotary shaft 3. The rotary shaft 3 is rotated together with the rotation in the R direction.

  A recess 62 that is open at the surface 55 and into which the elastic member 7 is inserted is a small-diameter arcuate inner peripheral surface 68 of the cylindrical portion 63, in the R direction, etc. across the small-diameter arcuate inner peripheral surface 68. One edge 71 in the R direction of each of the large-diameter arcuate inner circumferential surface 70 and the large-diameter arcuate inner circumferential surface 70 of the arc-shaped three protrusions formed with a space apart is formed on the small-diameter arcuate inner circumference. One flat side surface 73 connected to the surface 68 and extending radially from the axis O in the radial direction and the other edge 72 in the R direction of the large-diameter arcuate inner peripheral surface 70 are connected to the small-diameter arcuate inner peripheral surface. 68, and is defined by the other flat side surface 74 that extends radially from the axis O in the radial direction and the circular inner bottom surface 77 of the cylindrical portion 63. Thus, the recess 62 is a cylindrical concave portion. Three arcuate recess portions 80 spaced apart at equal angular intervals in the R direction at the outer edge in the radial direction of the recess portion 79 and the recess portion 79 It is equipped with.

  The pair of cam surfaces 33 and 34 and the pair of cam surfaces 53 and 54 that are slidably contacted with each other are rotated relative to the base portion 31 in the R direction, and the elastic force of the elastic member 7 is increased. The base 51 is relatively moved away from the base 31 in the A direction by sliding relative to the base 31. The separation distance of the base 51 relative to the base 31 in the A direction depends on the inclination angles of the cam surfaces 33 and 34 and the cam surfaces 53 and 54 and the relative rotation amount of the base 51 relative to the base 31. Yes.

  The pair of cam surfaces 33 and 34 are arranged with a flat surface 40 intersecting with the A direction in the R direction, and the pair of cam surfaces 53 and 54 are flat surfaces 56 intersecting with the A direction. In the R direction. Since the connecting bases 4 and 5 have the flat surfaces 40 and 56, respectively, the mechanical strength of the cam surfaces 33 and 34 and 53 and 54 can be maintained, and the cam surfaces 33 and 34 and 53 and 54 are deformed. Can be prevented.

  For example, the columnar elastic member 7 shown in FIG. 15 has a rigidity smaller than that of the rotating shafts 2 and 3 and the connecting bases 4 and 5 and is elastically deformable, and is integrally formed from a rubber elastic body such as urethane rubber or polyester elastomer. Has been.

  An outer peripheral surface 81 of the elastic member 7 arranged concentrically with the axis O is in contact with a small-diameter circular inner peripheral surface 68 of the cylindrical portion 63, and one circular surface 82 in the A direction of the elastic member 7 is a column The other circular surface 83 in the A direction of the elastic member 7 is in contact with the circular inner bottom surface 21 of the rotating shaft 3. Such an elastic member 7 is fitted into a cylindrical recess 79 of the recess 6279 and partially protrudes from the recess 79 in the A direction to elastically maintain the gap 6. The elastic member 7 is configured to cause the base portion 51 to relatively approach the A direction with respect to the base portion 31 due to its elastic force.

  In the shaft coupling mechanism 1 described above, when the electric motor controlled by the detection signal from the torque detector that detects the torque applied to the steering wheel is operated in the manual operation of the steering wheel by the driver, the rotating shaft 2 is moved. By rotating in the R direction, the connecting base 4 is rotated in the same direction, and this rotation causes a sliding movement while one of the cam surfaces 33 and 34 presses one of the cam surfaces 53 and 54 as shown in FIG. In this sliding movement, the connection base 5 moves closer to the circular inner bottom surface 21 in the direction A, and causes the elastic member 7 to be elastically deformed. When the length of the gap 6 in the A direction is reduced by a predetermined amount or more during the rotation and the elastic member 7 is contracted by the predetermined amount or more in the A direction, for example, as shown in FIG. One of the outer side surfaces 35 and 36 comes into contact with one of the inner side surfaces 25 and 26, and this contact prevents the pressing force in the A direction against one of the cam surfaces 53 and 54 of the cam surfaces 33 and 34. As a result, the sliding movement does not occur, and the rotation of the connecting base 4 in the R direction is caused by the rotation of one of the outer surfaces 35 and 36 and the inner surfaces 25 and 26. It is directly and rigidly transmitted to the rotary shaft 3 via one. The connection base 5 rotates in the same direction as the connection base 4 and the rotation shaft 3 rotate in the R direction. As a result, the shaft coupling mechanism 1 applies the rotational force in the R direction of the rotational shaft 2 to the rotational force in the R direction of the steering wheel, and the rotation of the rotational output shaft of the electric motor coupled to the rotational shaft 2 rotates. It is transmitted to the worm wheel meshing with the worm gear via the worm gear connected to the shaft 3, and the steering shaft is rotated by the rotation of the worm wheel, thus assisting the manual steering of the steering wheel connected to the steering shaft. In addition, the elastic member 7 that expands and contracts in the A direction does not cause elastic shear deformation (twist deformation) in the R direction.

  In the shaft coupling mechanism 1, the relative rotation in the R direction of the coupling base 5 with respect to the coupling base 4 causes the sliding movement of the pair of cam surfaces 53 and 54 with respect to the pair of cam surfaces 33 and 34. As a result of the length of the gap 6 in the A direction being reduced and the elastic member 7 being contracted in the A direction due to this reduction in length, for example, the relative rotation of the connecting base 4 with respect to the connecting base 5 in the minute R direction is elastic. The output of the electric motor connected to the rotary shaft 2 that is absorbed by the shortening of the member 7 in the A direction and is not transmitted to the connecting base 5 and thus causes the minute rotation of the connecting base 4 in the R direction, for example. In addition to being able to reduce the impact upon reversal of the rotating shaft and the transmission of brush vibration of the electric motor to the steering wheel via the connecting base 5, for example, a worm gear connected to the rotating shaft 3 (worm shaft) and the worm gear When they mesh The vibration caused by the backlash between the worm wheel and the worm wheel connected to the steering shaft can be absorbed by the expansion and contraction in the A direction of the elastic member 7, and the generation of noise such as rattling in the worm gear and the worm wheel can be eliminated. The driver's steering feeling can be improved. According to the shaft coupling mechanism 1, sliding movement of the pair of cam surfaces 53 and 54 relative to the pair of cam surfaces 33 and 34 is caused, and furthermore, elastic shear deformation (twist deformation) in the R direction is caused to the elastic member 7. As a result, early deterioration of the elastic member 7 can be avoided, and durability can be improved.

  According to the shaft coupling mechanism 1 arranged between the rotation shafts 2 and 3 so as to transmit the rotation of the rotation shafts 2 and 3 in the R direction to each other, the rotation shafts 2 and 3 are connected to each other. The rotation of the rotation shaft 3 in the R direction, and the connection base 4 connected to the rotation shaft 2 so as to rotate the rotation shaft 2 in the R direction by rotation in the R direction. , The connecting base 5 connected to the rotating shaft 3 so as to rotate the rotating shaft 3 in the R direction by rotating in the R direction, and between the connecting base 4 and the rotating shaft 2 in the A direction and A A gap 6 that is defined between at least one of the connection base 5 and the rotary shaft 3 in the direction, in this example, between the connection base 5 and the rotary shaft 3 and has a variable length in the A direction, and the rotary shaft The connecting base 5 that defines the gap 6 with respect to the rotating shaft 3 is As a contact surface that comes into contact with the rotary shaft 3 so that the connection base 4 does not move relative to the rotary shaft 3 in the R direction after moving a predetermined amount in the A direction to reduce the length of the gap 6 in the A direction. Outer surfaces 35 and 36 and an elastic member 7 disposed in the gap 6. The connecting base 4 is rotated in the R direction by the rotation of the rotating shaft 2 in the R direction, while rotating in the R direction. And at least a pair of base portions 31 connected to the rotation shaft 2 so as to rotate the rotation shaft 2 in the R direction, and one surface 32 in the A direction of the base portion 31 and inclined in directions opposite to each other in the R direction. The connecting base 5 is rotated in the R direction by the rotation of the rotation shaft 3 in the R direction, and the rotation shaft 3 is rotated in the R direction by the rotation in the R direction. A base 51 connected to the rotary shaft 3, and a base 5 And is formed on one surface 52 in the A direction, and has a shape complementary to the at least one pair of cam surfaces 33 and 34 inclined in the opposite directions in the R direction, and at least a pair of cams A pair of cam surfaces 53 and 54 that are slidably contacted relative to the surfaces 33 and 34 in the R direction, and the connecting base 5 that defines the gap 6 between the rotary shaft 3 and The relative sliding movement of the pair of cam surfaces 53 and 54 with respect to the pair of cam surfaces 33 and 34 moves in the A direction with respect to the rotary shaft 3 connected to the connection base 5 and moves the gap 6 in the A direction. In order to cause the length to increase or decrease, the rotary member 3 is movably connected in the A direction, and the elastic member 7 is elastically changed by increasing or decreasing the length of the gap 6 in the A direction. It is arranged in the gap 6 so as to be expanded and contracted Therefore, after the connecting base 5 has moved by a predetermined amount in the A direction with respect to the rotation axis 3 to reduce the length in the A direction, the rotation of the connecting base 4 in the R direction is not performed via the cam surfaces 33, 34, 53 and 54. Can be transmitted directly to the rotary shaft 3, a reduction of the length of the gap 6 in the A direction by a predetermined amount or more can be avoided, and the large compression deformation of the elastic member 7 can be prevented. The elastic member 7 does not cause elastic torsional deformation in the R direction. For example, the elastic member 7 is caused by impact when the output rotation shaft of the electric motor is reversed, transmission of brush vibration of the electric motor to the steering wheel, and backlash of the worm gear. Therefore, it is possible to reduce abnormal noise such as rattling and vibrations, improve the steering feeling of the driver, and avoid early deterioration.

  The shaft coupling mechanism 1 may include a base portion that is connected to the rotary shaft 2 so as to be movable in the A direction instead of the base portion 31. In this case, in addition to the elastic member 7, You may comprise the other elastic member distribute | arranged to the clearance gap where the length in the A direction between the rotating shafts 2 is variable.

  Further, the shaft coupling mechanism 1 is configured such that the elastic member 7 undergoes elastic deformation based on the sliding movement of the cam surfaces 33 and 34 with respect to one of the cam surfaces 53 and 54, so that the coupling base 5 is The surface 55 as a contact surface of the connecting base 5 that contacts the circular inner bottom surface 21 of the rotary shaft 3 after moving in the direction, in other words, the connecting base 5 that defines the gap 6 with the rotary shaft 3 is the rotary shaft. 3, the length of the gap 6 in the A direction is reduced with respect to 3, and then the connection base 5 is brought into contact with the rotary shaft 3 so as to be immovable in the A direction relative to the rotary shaft 3. The contact surface may be provided with a surface 55 as a contact surface. In such a case, an approaching movement of the connection base 5 with respect to the rotary shaft 3 in the A direction by a predetermined amount or more is caused by the contact of the surface 55 with the circular inner bottom surface 21. As a result of prohibition, the R direction of the connecting base 4 The rotation is rigidly transmitted to the connection base 5 via one of the cam surfaces 33 and 34 and one of the cam surfaces 53 and 54 without being elastically deformed by a certain level or more, and is transmitted to the connection base 5. The rotation in the R direction is rigidly transmitted to the rotary shaft 3. Even in such a shaft coupling mechanism 1, the elastic member 7 can be prevented from being greatly compressed and deformed to prevent early deterioration of the elastic member 7.

  20 to 27, the rotary shaft 102 and the rotary shaft 102 and the rotary shaft 102 on the worm shaft side in the R direction around the axis O of the rotary shaft 102 and the rotary shaft 103 on the worm shaft side of the electric power steering device are transmitted. A shaft coupling mechanism 100 for an electric power steering apparatus according to another example of the present invention, which is arranged between 103 and couples the rotary shafts 102 and 103 to each other, is rotated in the same direction by rotating the rotary shaft 102 in the R direction. While the rotating base 102 is rotated in the same direction by the rotation in the R direction, and the rotating base 103 is rotated in the same direction by the rotation in the R direction. , A connecting base 105 connected to the rotating shaft 103 so as to rotate the rotating shaft 103 in the same direction by rotation in the R direction, and a connecting base 104 and the rotating shaft 103 in the A direction. In this example, the elastic member 107 is disposed in the gap 106 having a variable length L in the A direction between the connection base 105 and the rotation shaft 103 in the A direction. It is equipped with.

  On the end surface 112 of the end portion 111 in the A direction of the rotating shaft 102, as shown particularly in FIG. 20, the above-described fitting protrusion 13 is integrally formed.

  As shown in FIGS. 20 and 27 in particular, the end portion 115 of the rotating shaft 103 in the A direction protrudes from the end surface 116 of the end portion 115 in the A direction and fits into the connecting base body 105. Are integrally formed. The fitting protrusion 117 is integrally formed with a cylindrical portion 118 that is integrally formed extending from the end surface 116 in the A direction, and a cylindrical outer peripheral surface 119 and an end surface 116 in the radial direction of the cylindrical portion 118. Two arc-shaped radial protrusions 120 projecting in the radial direction and spaced apart at equal angular intervals in the R direction are provided.

  As shown in FIGS. 21 and 22, the connecting base 104 is rotated in the same direction by the rotation of the rotation shaft 102 in the R direction, while rotating so that the rotation shaft 102 is rotated in the same direction by the rotation in the R direction. A base portion 131 connected to the shaft 102; and three pairs of cam surfaces 133 and 134 that are integrally formed on one surface 132 in the A direction of the base portion 131 and inclined in opposite directions in the R direction. ing.

  The base 131 includes a cylindrical portion 43 having the fitting recess 42 described above and three arc-shaped axial protrusions 47, and the cam surfaces 133 and 134 are the same as the cam surfaces 33 and 34. And formed on the end surface in the A direction of each of the axial protrusions 47.

  The fitting protrusion 42 of the rotating shaft 102 is fitted in the fitting recess 42 of the base 131, and the coupling base 104 rotates with the fitting protrusion 13 fitted in the fitting recess 42. The rotation in the R direction on one of the shafts 102 is transmitted to the other of the connection base 104 and the rotation shaft 102.

  As shown in FIGS. 23 to 25, the connecting base body 105 is rotated in the same direction by the rotation of the rotation shaft 103 in the R direction, and rotated so as to rotate the rotation shaft 103 in the same direction by the rotation in the R direction. The base 151 connected to the shaft 103 and the one surface 152 in the A direction of the base 151 are integrally formed and inclined in opposite directions in the R direction to be complementary to the cam surfaces 133 and 134, respectively. The three cam surfaces 153 and 154 have a shape and are in contact with the cam surfaces 133 and 134 so as to be relatively slidable in the R direction.

  The base portion 151 has a shape complementary to the fitting protrusion 117 and has a cylindrical portion 163 having a fitting recess 162 opened at one surface 161 in the A direction, and one end surface in the A direction of the cylindrical portion 163. 166 and three arc-shaped axial projections 167 protruding in the A direction and spaced apart at equal angular intervals in the R direction, and three pairs of cam surfaces 153 and Each of 154 is formed on the end surface in the A direction of each of the three axial protrusions 167. Each of the three pairs of cam surfaces 153 and 154 is formed in the same manner as each of the three pairs of cam surfaces 53 and 54 described above.

  A fitting projection 117 of the rotary shaft 103 is fitted in the fitting recess 162 of the cylindrical portion 163 so as to be movable in the A direction, and the fitting projection 117 fitted in the fitting recess 162 is interposed. Thus, the rotation in the R direction on one of the connection base 105 and the rotation shaft 103 is transmitted to the other of the connection base 105 and the rotation shaft 103.

  The fitting recess 162 includes a small-diameter arc inner peripheral surface 168, two large-diameter arc inner peripheral surfaces 170 formed at equal angular intervals in the R direction across the small-diameter arc inner peripheral surface 168 in the R direction, One edge 171 in the R direction of each of the large-diameter arc inner peripheral surfaces 170 is connected to the small-diameter arc inner peripheral surface 168 and one flat inner side surface 173 extending radially from the axis O in the radial direction, a large-diameter arc The other edge 172 in the R direction of each inner peripheral surface 170 is connected to the small-diameter circular arc inner peripheral surface 168 and is defined by the other flat inner side surface 174 and circular inner bottom surface 177 extending radially from the axis O. Thus, the recess 162 includes a cylindrical recess portion 179 and two arc-shaped recess portions spaced at equal angular intervals in the R direction at the radial outer edge of the recess portion 179. 180.

  In such a fitting recess 162, a fitting protrusion 117 of the rotating shaft 103 is fitted so as to be movable in the A direction. The small-diameter circular arc inner peripheral surface 168 of the connection base 105 is disposed with a gap 106 whose length L in the A direction is variable with respect to the front end surface 121 in the A direction of the fitting protrusion 117 of the rotating shaft 103.

  The outer peripheral surface 119 of the fitting protrusion 117 is in contact with the small-diameter arc inner peripheral surface 168 of the cylindrical portion 163 so as to be slidable in the A direction, and each of the radial protrusions 120 is disposed in each of the recess portions 180. And two arc outer peripheral surfaces 122 extending in directions around the axial centers of the two radial protrusions 120 spaced apart at equal angular intervals in the R direction on the outer peripheral surface 119 of the fitting protrusion 117. The large-diameter arc inner peripheral surface 170 is slidably in contact with the A direction.

  The length of the two arc-shaped radial protrusions 120 in the R direction is equal to the length of the two arc-shaped recesses 180 in the R direction. The flat outer surfaces 125 and 126 of the radial protrusion 120 connected to the surface 119 and extending radially from the axis O in the radial direction are slidable in the A direction on the inner surfaces 173 and 174, respectively. It touches. In this way, the coupling base 105 fitted to the rotary shaft 103 so as to be slidable in the A direction has the outer side surfaces 125 and 126 as rigid rotation transmission surfaces in contact with the inner side surfaces 173 and 174. On the other hand, it is relatively immovable in the R direction, and the rotation of the connection base 105 in the R direction is directly transmitted to the rotating shaft 103.

  The pair of cam surfaces 133 and 134 and the pair of cam surfaces 153 and 154 that are slidably contacted with each other are rotated in the R direction relative to the base portion 131 by the relative force of the elastic member 107. The base 151 is relatively moved away from the base 131 relative to the base 131 by sliding relatively. The separation distance of the base 151 relative to the base 131 with respect to the base 131 depends on the inclination angles of the cam surfaces 133 and 134 and the cam surfaces 153 and 154 and the amount of rotation of the base 151 relative to the base 131 in the R direction. Yes.

  The pair of cam surfaces 133 and 134 are arranged with a flat surface 140 intersecting with the A direction in the R direction, and the pair of cam surfaces 153 and 154 are flat surfaces 156 intersecting with the A direction. In the R direction. Since the coupling bases 104 and 105 have the flat surfaces 140 and 156, respectively, the mechanical strength of the cam surfaces 133 and 134 and 153 and 154 can be maintained, and the cam surfaces 133 and 134 and 153 and 154 can be deformed. Can be prevented.

  The connection base 105 has a predetermined amount in the A direction that reduces the length in the A direction of the gap 106 with respect to the rotating shaft 103 in order to avoid a decrease in the length L of the gap 106 in the A direction by a predetermined amount or more. It is connected to the rotary shaft 103 so that it does not move in the A direction with respect to the rotary shaft 103 after the movement. In the shaft coupling mechanism 100, the coupling substrate 105 that defines the gap 106 with the rotation shaft 103 moves with respect to the rotation shaft 103 by a predetermined amount in the A direction that reduces the length of the gap 106 in the A direction. Is provided with a circular inner bottom surface 177 as a contact surface that comes into contact with the tip surface 121 of the rotary shaft 103 so as to be immovable relative to the rotary shaft 103 in the A direction. As a result of the approach movement of the shaft 103 exceeding the predetermined amount in the A direction being prohibited by the contact of the circular inner bottom surface 177 with the tip surface 121, the rotation of the connecting base body 104 in the R direction is accompanied by elastic deformation of the elastic member 107 above a certain level. Rather, it is rigidly transmitted to the connection base 105 through one of the cam surfaces 133 and 134 and one of the cam surfaces 153 and 154, and is transmitted to the connection base 105 in the R direction. Rolling is rigidly transmitted to the rotary shaft 103. According to such a shaft coupling mechanism 100, the elastic member 107 can be prevented from being greatly compressed and deformed, and early deterioration of the elastic member 107 can be prevented.

  As shown particularly in FIG. 26, the elastic member 107 has a rigidity smaller than that of the rotating shaft 103 and the connecting bases 104 and 105, is elastically deformable, and is integrally formed from a rubber elastic body such as urethane rubber or polyester elastomer. The disc portion 191 is formed, and the center of the disc portion 191 is formed so as to penetrate in the A direction, and the fitting protrusion 117 and the through hole 192 having a complementary shape are provided.

  One circular surface 193 in the A direction of the disk portion 191 is in contact with the end surface 116 of the rotating shaft 103, and the other circular surface 194 in the A direction of the disk portion 191 is in contact with the surface 161 of the columnar portion 163. The fitting projection 117 is inserted into the through hole 192 so as to be movable in the A direction. The elastic member 107 elastically maintains the gap 106 by elastically maintaining the distance from the surface 161 to the end surface 116. Such an elastic member 107 is configured to cause the base 151 to move relatively in the A direction with respect to the base 131 due to its elastic force.

  In the shaft coupling mechanism 100 described above, when the electric motor controlled by the detection signal from the torque detector that detects the torque applied to the steering wheel is operated in the manual operation of the steering wheel by the driver, the rotating shaft 102 is moved. By rotating in the R direction, the connecting base 104 is rotated in the same direction. As a result of this rotation, one of the cam surfaces 133 and 134 slides while pressing one of the cam surfaces 153 and 154. 105 moves close to the end surface 116 in the direction A to cause the elastic member 107 to be elastically deformed. Based on the sliding movement of one of the cam surfaces 133 and 134 with respect to one of the cam surfaces 153 and 154, the elastic member 107 undergoes elastic deformation, and the connection base 105 moves closer to the rotation shaft 103 in the A direction and the connection is made. When the circular inner bottom surface 177 of the base body 105 comes into contact with the tip surface 121 of the fitting protrusion 117 of the rotating shaft 103, the connecting base body 105 is prohibited from approaching the rotating shaft 103, and as a result, the connecting base body 104 in the R direction. The rotation of the elastic member 107 is rigidly transmitted to the connection base 105 via one of the cam surfaces 133 and 134 and one of the cam surfaces 153 and 154 without causing elastic deformation of the elastic member 107 beyond a certain level. The transmitted rotation in the R direction is rigidly transmitted to the rotating shaft 103. As a result, the shaft coupling mechanism 100 adds the rotational force in the R direction of the rotational shaft 102 to the rotational force in the R direction of the steering wheel, and the rotation of the rotational output shaft of the electric motor coupled to the rotational shaft 102 rotates. It is transmitted to the worm wheel meshing with the worm gear via the worm gear connected to the shaft 103, and the steering shaft is also rotated by the rotation of the worm wheel, thus assisting the manual steering of the steering wheel connected to the steering shaft. In addition, elastic shear deformation (twist deformation) in the R direction is not caused in the elastic member 107 that expands and contracts in the A direction.

  In the shaft coupling mechanism 100, the relative rotation in the R direction of the coupling base 105 with respect to the coupling base 104 causes the sliding movement of the pair of cam surfaces 153 and 154 with respect to the pair of cam surfaces 133 and 134. The length of the gap 106 in the A direction is reduced, and the elastic member 107 is contracted in the A direction due to the reduction in the length. As a result, for example, the relative rotation of the connecting base 104 with respect to the connecting base 105 in the minute R direction The output of the electric motor connected to the rotating shaft 102 that is absorbed by the shortening of the member 107 in the A direction and is not transmitted to the connecting base 105 and thus causes the minute rotation of the connecting base 104 in the R direction, for example. In addition to reducing the impact at the time of reversal of the rotating shaft and the transmission of brush vibration of the electric motor to the steering wheel via the connecting base 105, the rotating shaft 103 is connected to the rotating shaft 103, for example. The vibration caused by the backlash between the worm gear (worm shaft) and the worm wheel meshed with the worm gear and coupled to the steering shaft can be absorbed by the expansion and contraction of the elastic member 107 in the A direction. Generation of abnormal noise such as hitting can be eliminated, and the steering feeling of the driver can be improved. According to the shaft coupling mechanism 100, the pair of cam surfaces 153 and 154 slide with respect to the pair of cam surfaces 133 and 134, and the elastic member 107 undergoes elastic shear deformation (twist deformation) in the R direction. As a result, early deterioration of the elastic member 107 can be avoided, and durability can be improved.

  The shaft coupling mechanisms 1 and 100 of the present example are suitable for use in an electric power steering apparatus, but instead, for example, suppress changes in camber angle and ground tread due to wheel bumps and rebound. In order to enhance steering stability performance, the telescopic actuator controls the expansion and contraction of the upper link and the lower link of the suspension system of the vehicle, and is used, for example, as a toe control actuator as a telescopic actuator that connects the knuckle of the suspension of the automobile and the vehicle In this case, one of the connection bases 4 and 104 and the connection bases 5 and 105 is an output member of a speed reducer connected to the rotation shaft of a brushed motor of a toe control actuator located on the vehicle body side. Connected to the rotating shaft and aligned with the connecting bases 4 and 104 The other connection base 5 and 105 may be coupled to the rotating shaft is an input member of the feed screw mechanism of the toe control actuator located on the knuckle side.

DESCRIPTION OF SYMBOLS 1,100 Shaft coupling mechanism 2,102 Rotating shaft 3,103 Rotating shaft 4,104 Connecting base 5,105 Connecting base 6,106 Crevice 7,107 Elastic member

Claims (15)

The shaft coupling mechanism is arranged between the first and second rotating shafts so as to transmit the rotations of the first and second rotating shafts to each other and connects the first and second rotating shafts to each other. The first rotating base is connected to the first rotating shaft so that the first rotating shaft is rotated by the rotation of the first rotating shaft, and the second rotating shaft is rotated. A second connecting base coupled to the second rotating shaft so as to rotate the second rotating shaft by rotation, and between the first connecting base and the first rotating shaft in the axial direction. A gap defined between at least one of the second connecting base and the second rotating shaft in the axial direction and having a variable length in the axial direction, and the first and second rotating shafts One of the first and second connecting bases defining the gap with the one rotation shaft After the bonded base body moves by a predetermined amount in the axial direction to reduce the axial length of the gap with respect to the one rotation axis, the one connection base body is moved in the axial direction relative to the one rotation axis. After the contact surface that contacts the one rotating shaft and the one connecting base move in a predetermined amount in the axial direction to reduce the axial length of the gap with respect to the one rotating shaft so that they do not move, At least one of the contact surfaces in contact with the one rotation shaft so that the other connection substrate of the first and second connection substrates does not move in the rotation direction relative to the one rotation shaft. A contact surface and an elastic member disposed in the gap, wherein the first connection base is rotated by the rotation of the first rotation shaft, and the first rotation shaft is rotated by the rotation; A first base coupled to the first rotating shaft, and the first base At least one pair of first cam surfaces that are formed on one surface in the axial direction of the base and are inclined in opposite directions in the rotational direction. A second base connected to the second rotary shaft so as to rotate the second rotary shaft by rotation, and one axial surface of the second base. And having a shape complementary to the at least one pair of first cam surfaces and inclined in directions opposite to each other in the rotation direction, and in the rotation direction with respect to the at least one pair of first cam surfaces. A pair of second cam surfaces in contact with the at least one pair of first cam surfaces so as to be relatively slidable, and the one connecting base is a pair of the first cam surfaces. The relative sliding movement of the second cam surface To increase or decrease the axial length of the gap by moving in the axial direction with respect to at least one of the first and second rotating shafts connected to at least one of the connecting bases, The elastic member is movably coupled in the axial direction with respect to the at least one rotating shaft, and the elastic member is provided in the gap so that the elastic member is elastically expanded and contracted by increasing or decreasing the axial length of the gap. A shaft coupling mechanism.   The first connection base has a fitting recess formed in the first base portion and a fitting protrusion formed integrally with the axial end of the first rotating shaft. The rotation of one of the first connecting base and the first rotating shaft through the fitting protrusions fitted in the fitting recess is performed by the first connecting base and the first rotating shaft. The shaft coupling mechanism according to claim 1, wherein the shaft coupling mechanism is transmitted to the other of the two.   The first connecting base has a fitting protrusion formed integrally with the first base and fitted in a fitting recess formed at an axial end of the first rotating shaft. The rotation of one of the first connecting base and the first rotating shaft through the fitting protrusions fitted in the fitting recess is performed by the first connecting base and the first rotating shaft. The shaft coupling mechanism according to claim 1 or 2, wherein the shaft coupling mechanism is transmitted to the other of the two.   The second connection base has a fitting recess formed in the second base portion and a fitting protrusion formed integrally with the axial end of the second rotating shaft. The rotation of one of the second connecting base and the second rotating shaft via the fitting protrusions fitted in the fitting recess is caused by the second connecting base and the second rotating shaft. The shaft coupling mechanism according to any one of claims 1 to 3, wherein the shaft coupling mechanism is transmitted to the other of the two.   The second connecting base has a fitting protrusion formed integrally with the second base portion and fitted in a fitting recess formed at the axial end of the second rotating shaft. The rotation of one of the second connecting base and the second rotating shaft via the fitting protrusions fitted in the fitting recess is caused by the second connecting base and the second rotating shaft. The shaft coupling mechanism according to any one of claims 1 to 4, wherein the shaft coupling mechanism is transmitted to the other of the two.   The pair of first cam surfaces and the pair of second cam surfaces that are slidably contacted with each other are relatively rotated by the second base portion with respect to the first base portion. The shaft coupling according to any one of claims 1 to 5, wherein the second base portion is relatively axially separated from the first base portion by sliding relative to the first base portion. mechanism.   The relative axial separation distance of the second base with respect to the first base is the angle of inclination of the first cam surface and the second cam surface and the relative amount of rotation of the second base with respect to the first base. The shaft coupling mechanism according to claim 6 that depends on   The pair of first cam surfaces are arranged with a first flat surface intersecting the axial direction in the rotational direction, and the pair of second cam surfaces intersects the axial direction. The shaft coupling mechanism according to any one of claims 1 to 7, wherein the two flat surfaces are arranged with a rotation direction therebetween.   The first base is connected to the first rotation shaft so as to be relatively movable in the axial direction, and the second base is connected to the second rotation shaft in an axially immovable manner. The shaft coupling mechanism according to any one of claims 1 to 8, which is configured as described above.   The shaft coupling mechanism according to claim 9, wherein the elastic member is arranged in a gap having a variable length in the axial direction between the first coupling base and the first rotation shaft in the axial direction.   The first base is connected to the first rotating shaft in an axially stationary manner, and the second base is connected to the second rotating shaft so as to be relatively movable in the axial direction. The shaft coupling mechanism according to any one of claims 1 to 8, which is configured as described above.   The shaft coupling mechanism according to claim 11, wherein the elastic member is arranged in a gap having a variable length in the axial direction between the second coupling base and the second rotation shaft in the axial direction.   The first base is connected to the first rotating shaft and the second base is connected to the second rotating shaft so as to be relatively movable in the axial direction, respectively. The shaft coupling mechanism as described in any one of Claims.   Two elastic members are provided, and one elastic member is arranged in a gap having a variable length in the axial direction between the first connecting base in the axial direction and the first rotating shaft. The shaft coupling mechanism according to claim 13, wherein the other elastic member is arranged in a gap in which the length in the axial direction between the second coupling base and the second rotation shaft in the axial direction is variable. .   The shaft coupling mechanism according to any one of claims 1 to 14, wherein the elastic member causes the second base portion to relatively approach the first base portion in the axial direction by its elastic force. .

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