JP2009014154A - Shaft connecting mechanism for electric power steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a shaft connecting mechanism for an electric power steering device that hardly causes rattling in the direction of rotation around an axis between one rotating shaft and the other rotating shaft, for example, between a rotating shaft connected to an output rotating shaft of an electric motor and a steering shaft connected to a steering wheel, and that can reduce an impact at the time of an electric motor's reverse rotation and a brush vibration transfer to the steering wheel; thereby giving long durability of the motor and a comfortable steering feeling. <P>SOLUTION: The shaft connecting mechanism for electric power steering devices 1 comprises: a linkage base 3 connected to a rotating shaft 2; a linkage base 5 connected to a rotating shaft 4; a pair of rotation transfer members 6 and 7 which are overlapped in the 'A' direction; a middle insertion member 8 inserted between the pair of the rotation transfer members 6 and 7 in the 'A' direction; and a connection means 9 connecting the pair of the rotation transfer member 6 and 7 by sandwiching the middle insertion member 8 in the middle. <P>COPYRIGHT: (C)2009,JPO&INPIT

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.

Special table 2002-518242 gazette JP 2004-148990 A JP 2004-149070 A JP 2006-183676 A

  The electric power steering apparatus can easily perform manual steering of the steering wheel by adding the rotational force based on the rotation of the output rotation shaft of the electric motor to the rotational force based on the rotation of the manually operated steering wheel (handle). In such an electric power steering device, the steering shaft on the steering wheel side and the rotating shaft on the output rotating shaft side of the electric motor are coupled via a shaft coupling mechanism (coupling). Yes.

  When the steering shaft and the rotating shaft are connected via the shaft connecting mechanism, the impact when the output rotating shaft of the electric motor is reversed and the brush vibration of the electric motor are transmitted to the steering wheel via the shaft connecting mechanism and the steering shaft. There is a possibility of causing an unpleasant steering feeling to the driver, and in order to avoid this, it has been proposed to provide a spacer such as rubber or soft resin in the shaft coupling mechanism.

  By the way, if the spacer is made more flexible by placing importance on the reduction of impact and vibration, the flexible spacer is likely to undergo creep deformation. Therefore, the shaft coupling mechanism is not rattled by permanent deformation of the spacer due to repeated load on the spacer. This may also cause the driver's steering feeling to be uncomfortable.

  On the other hand, if the spacers are made harder with emphasis on durability, the steering feeling will be better in the absence of backlash, but the steering feeling is uncomfortable due to the impact and vibration transmitted to the steering wheel as described above. It will be a thing.

  The present invention has been made in view of the above-mentioned points. The object of the present invention is to provide a rotary shaft connected to an output rotary shaft of an electric motor, for example, the rotary shaft and the other rotary shaft, even after long-term use. For example, there is little backlash in the direction around the axis between the rotating shaft, for example, the steering shaft connected to the steering wheel, and it is possible to reduce the impact when the electric motor is reversed and the transmission of brush vibration to the steering wheel. Accordingly, it is an object of the present invention to provide a shaft coupling mechanism for an electric power steering apparatus that has excellent durability and does not make the steering feeling uncomfortable.

  The shaft coupling mechanism according to the present invention, which is arranged between two rotation shafts so as to transmit the rotation of one rotation shaft to the other rotation shaft and connects the two rotation shafts, is a pair of rotations that are overlapped in the axial direction. A transmission member and an intermediate interposed member interposed between the pair of rotation transmission members, and each of the pair of rotation transmission members is mutually connected in the direction around the annular outer diameter side base and the axis. The intermediate interposed member has a pair of rotations in the axial direction and has at least a pair of protrusions that are spaced apart and extend integrally from the inner peripheral surface of the outer diameter side base portion toward the central direction in the radial direction. An annular intermediate outer diameter side base portion disposed between the outer diameter side base portions of the transmission member, and an inner peripheral surface of the intermediate outer diameter side base portion integrally extending in the radial direction toward the center and Width in the direction around the shaft center at each protrusion of the rotation transmission member Each of the pair of protrusions of the intermediate interposed member disposed between the pair of protrusions of the pair of rotation transmission members in the axial direction is each of the rotation transmissions. It has a rigidity smaller than the rigidity of each protrusion of the member and can be elastically deformed.

  According to the shaft coupling mechanism of the present invention, the intermediate interposed member is disposed between the pair of protrusions of the pair of rotation transmission members in the axial direction, and in the direction around the axis of each protrusion of each rotation transmission member. As a result of having the pair of protrusions having a width larger than the width, the rotation of one rotating shaft is transmitted to the other rotating shaft through the elastic deformation of the pair of protruding portions of the intermediate interposed member. Therefore, transmission of minute rotation of one rotating shaft to the other rotating shaft can be reduced or prevented by elastic deformation of the pair of protrusions of the intermediate interposed member, and large rotation of one rotating shaft with respect to the other rotating shaft can be achieved. Transmission to the other rotation shaft can be performed as it is through the pair of protrusions of the pair of rotation transmission members having rigidity greater than that of the pair of protrusions of the intermediate interposed member. Elastic change in the direction around the axis of the protrusion Then, since the pair of protrusions of the pair of rotation transmission members having large rigidity can prevent the large deformation of the pair of protrusions of the intermediate interposed member, a flexible resin material with low rigidity is applied to the intermediate interposed member. Even if it is used, permanent deformation of the intermediate interposed member due to creep can be reduced, and in addition, the inner peripheral surface of the annular intermediate outer diameter side base portion disposed between the outer diameter side base portions of the pair of rotation transmission members in the axial direction Since the pair of protrusions of the intermediate interposed member integrally extend in the radial direction toward the central direction, the pair of protrusions of the intermediate interposed member can be firmly held, and thus, a long-term Depending on the use, there is a backlash in the direction around the shaft center between one rotating shaft, for example, the rotating shaft connected to the output rotating shaft of the electric motor, and the other rotating shaft, for example, the steering shaft connected to the steering wheel. Arise In addition, it is possible to provide a shaft coupling mechanism for an electric power steering device that can reduce the impact at the time of reversal of the electric motor and the transmission of brush vibration to the steering wheel and has excellent durability and does not make the steering feeling uncomfortable. it can.

  The projecting portion of the intermediate interposed member may be a free end at a tip portion extending radially from the inner peripheral surface of the intermediate outer diameter side base portion toward the central direction. The intermediate interposed member is provided with an intermediate inner diameter side base that is concentric with the outer diameter side base and disposed radially inward of the intermediate outer diameter side base, and the intermediate inner member protrudes from the intermediate inner diameter side base. The front end of each part may be fixed integrally, and each protrusion of the rotation transmitting member is also a front end that extends radially from the inner peripheral surface of the outer diameter side base toward the center. Instead of this, instead of this, similarly to the intermediate interposed member, an inner diameter side base portion that is concentric with the outer diameter side base portion and is arranged radially inward from the outer diameter side base portion is provided. Each rotation transmission member is provided, and the tip of each protrusion of the rotation transmission member is integrally fixed to the inner diameter side base. In any case, each of the protrusions of the rotation transmitting member and the protrusions of the intermediate interposed member may be preferably terminated so that their end envelopes form a concentric circle. Can do.

  The shaft coupling mechanism only needs to include a rotation transmission member and an intermediate interposition member disposed between two rotation shafts as a spacer in the direction around the shaft center. And the other connecting base connected to the other rotating shaft. In this case, one connecting base protrudes integrally from the base and the base in the axial direction. And the other connecting base includes a base and a protrusion integrally protruding in the axial direction from the base, and the protrusion of the one connecting base is around the axis. Between one pair of protrusions of each pair of rotation transmitting members in the direction of the center and between one protrusion of the pair of protrusions of the intermediate interposed member in the direction around the axis. The projection of the other connecting base is formed by the pair of rotation transmitting members in the direction around the axis. It may have been disposed between the other projecting portion of the pair of protrusions of the intermediate interposed member in the other projection and between the direction around the axis of between pairs of projections.

  In such a shaft coupling mechanism, the protrusions of the one and the other coupling bases are on the respective side surfaces in the direction around the axis, and the intermediate interposed members that face in the direction around the axis when the rotation of the two rotation shafts is less than a certain amount. While contacting the side surface in the direction around the axial center of the protrusion, the side surfaces in the direction around the axial center of the pair of rotation transmitting members facing in the direction around the axial center are below a certain value of both rotation shafts. It is desirable that the relative rotation is non-contact and the two rotation shafts are in contact with each other at a certain relative rotation.

  The shaft coupling mechanism of the present invention may further include coupling means for coupling the pair of rotation transmission members to each other.

  In any of the shaft coupling mechanisms of the present invention, the rotation transmission member is preferably formed from a hard resin such as polyacetal resin or polyamide resin, but may be formed from a hard resin exhibiting other rigidity. The intermediate interposed member may be formed of a rubber elastic body such as urethane rubber, silicone rubber, or polyester elastomer.

  The shaft coupling mechanism of the present invention may be for an electric power steering apparatus. In this case, one rotating shaft is coupled to the output rotating shaft of the electric motor, and the other rotating shaft. The shaft may be connected to the steering shaft of the automobile.

  According to the present invention, even when used for a long time, between one rotating shaft, for example, the rotating shaft connected to the output rotating shaft of the electric motor, and the other rotating shaft, for example, the steering shaft connected to the steering wheel. Electric type that does not cause looseness in the direction around the shaft center, and that can reduce the impact of the electric motor when it is reversed and the transmission of brush vibration to the steering wheel. A shaft coupling mechanism for a power steering apparatus can be provided.

  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 shaft coupling mechanism 1 for the electric power steering apparatus of this example includes a coupling base 3 coupled to the rotary shaft 2, a coupling base 5 coupled to the rotary shaft 4, and an axial direction. A pair of rotation transmission members 6 and 7 overlapped in a certain A direction, an intermediate interposed member 8 interposed between the pair of rotation transmission members 6 and 7 in the A direction, and a pair of intermediate transmission members 8 The rotation transmitting members 6 and 7 are coupled to each other, and two rotations are performed so as to transmit the rotation around the axis O of the rotating shaft 2, that is, the rotation in the R direction, to the rotating shaft 4. It arrange | positions between the shafts 2 and 4, and connects the two rotating shafts 2 and 4. As shown in FIG.

  The rotating shaft 2 is a rotating shaft on the electric motor side of the electric power steering device, and is connected to the output rotating shaft of the electric motor. It is designed to rotate in the direction.

  The rigid connecting base 3 is integrally protruded from the annular base portion 11 and one annular surface 12 of the base portion 11 in the A direction and spaced apart from each other at an equal angular interval of 90 ° in the R direction. Four triangular prism-shaped projections 13 and a through-hole 14 into which the rotary shaft 2 is fitted are provided. Each of the protrusions 13 has side surfaces 17 and 18 as a pair of rigid rotation transmission surfaces in the R direction.

  The rotating shaft 4 is a rotating shaft connected to the steering wheel so as to be rotated by operation (steering) of the steering wheel, and the rotating shaft 4 is also rotated in the R direction as the connecting base 5 rotates in the R direction. It has become.

  The rigid connecting base 5 is integrally protruded from the annular base portion 21 and one annular surface 22 of the base portion 21 in the A direction and spaced apart from each other at an equal angular interval of 90 ° in the R direction. Four triangular prism-shaped projections 23 and a through hole 24 into which the rotary shaft 4 is fitted are provided. Each of the protrusions 23 has side surfaces 27 and 28 as a pair of rigid rotation transmission surfaces in the R direction.

  The rigid rotation transmission member 6 integrally formed of polyacetal resin, polyamide resin, or the like is spaced apart from the annular outer diameter side base portion 32 having the annular outer peripheral surface 31 at equal angular intervals in the R direction. And eight protrusions 34 integrally extending radially from the inner peripheral surface 33 of the outer diameter side base 32 concentrically with the outer peripheral surface 31 toward the central direction.

  Each of the protrusions 34 that are arranged at equal angular intervals of 45 ° in the R direction and that are integrally formed with the inner circumferential surface 33 of the outer diameter side base portion 32 with a width d in the R direction are the tip portions 35 thereof. And has a side surface 38 and 39 as a pair of rigid rotation transmission surfaces in the R direction.

  Outer end surfaces 41 and 42 which are one end surfaces in the A direction of the outer diameter side base portion 32 and the respective protrusions 34 are flush with each other, and the other end surfaces of the outer diameter side base portion 32 and the respective protrusions 34 in the A direction are the same. The inner end surfaces 44 and 45 are also flush with each other, and the inner peripheral surface 33 of the outer diameter side base portion 32 and the side surfaces 38 and 39 of the protrusion 34 have eight pieces into which the protrusion 13 and the protrusion 23 are inserted. A substantially triangular prism-shaped space 47 is defined.

  The rigid rotation transmission member 7 integrally formed of polyacetal resin, polyamide resin or the like is formed in the same manner as the rotation transmission member 6 and has an annular outer diameter side base portion 52 having an annular outer peripheral surface 51. And eight protrusions 54 that are spaced apart from each other at equal angular intervals in the R direction and that extend radially from the inner peripheral surface 53 of the outer diameter side base portion 52 toward the central direction. ing.

  The protrusions 54 are arranged at equal angular intervals of 45 ° in the R direction, and are integrally formed on the inner peripheral surface 53 of the outer diameter side base 52 with the same width d in the R direction as the protrusion 34. Is a free end having an arc concave surface 56 at its tip 55 and has side surfaces 58 and 59 as a pair of rigid rotation transmission surfaces in the R direction.

  The outer end surfaces 61 and 62 which are one end surfaces in the A direction of the outer diameter side base portion 52 and the respective protrusions 54 are flush with each other, and the other end surfaces of the outer diameter side base portion 52 and the respective protrusions 54 in the A direction are the same. The inner end surfaces 64 and 65 are also flush with each other, and the inner peripheral surface 53 of the outer diameter side base 52 and the side surfaces 58 and 59 of the protrusion 54 are eight pieces into which the protrusion 13 and the protrusion 23 are inserted. A triangular prism-shaped space 67 is defined.

  It is arranged between the rotation transmission members 6 and 7, has a smaller rigidity than the rotation transmission members 6 and 7, is elastically deformable, and is integrally formed from a rubber elastic body such as urethane rubber, silicone rubber, or polyester elastomer. The intermediate intermediate member 8 is arranged between the outer diameter side base portions 32 and 52 of the rotation transmitting members 6 and 7 in the A direction and has an annular intermediate outer diameter side base portion having an annular outer peripheral surface 71. 72 and an inner peripheral surface 73 of the intermediate outer diameter side base 72 concentric with the outer peripheral surface 71 and extending in the radial direction integrally toward the center, and the width d in the R direction at each pair of protrusions 34 and 54 And eight protrusions 74 having a larger width D.

  It is the same as the total number of the protrusions 34 and 54 of each of the rotation transmitting members 6 and 7, and is spaced apart from each other at equiangular intervals of 45 ° in the R direction, and the intermediate outer diameter side base 72. Each of the protrusions 74 formed integrally with the inner peripheral surface 73 is disposed between the corresponding pair of protrusions 34 and 54 of the pair of rotation transmitting members 6 and 7 in the A direction, and the protrusion 34 and 54 has a width D greater than the width d in the R direction. Each of the protrusions 74 having rigidity smaller than the rigidity of the protrusions 34 and 54 of the rotation transmitting members 6 and 7 and elastically deformable is a free end having an arc concave surface 76 at the tip 75. And side surfaces 78 and 79 in the R direction.

  The end surface 81 which is one end surface in the A direction of the intermediate outer diameter side base 72 and each protrusion 74 is flush with the other end surface 82 in the A direction of the intermediate outer diameter side base 72 and each protrusion 74. The flat end face 81 faces the flat inner end faces 44 and 45 of the rotation transmitting member 6 and is slidably in contact with the inner end faces 44 and 45, and the flat end face 82. Faces the flat inner end surfaces 64 and 65 of the rotation transmitting member 7 and is slidably in contact with the inner end surfaces 64 and 65, and the inner peripheral surface 73 of the outer diameter side base 72 and the side surfaces of the protrusion 74. Reference numerals 78 and 79 define eight triangular prism-shaped spaces 87 into which the protrusions 13 and 23 are inserted.

  The side surface 78 of each protrusion 74 is in contact with the side surface 17 of each protrusion 13 and the side surface 27 of each protrusion 23 alternately in the R direction, and the side surface 79 of each protrusion 74 is the side surface of each protrusion 13. 18 and the side surface 28 of each protrusion 23 are alternately in contact in the R direction.

  The side surface 17 of each protrusion 13 is on the side surface 39 of every other protrusion 34 and the side surface 58 of every other protrusion 54, and the side surface 18 of each protrusion 13 is on every other protrusion. 34 side surfaces 38 and side surfaces 59 of every other projection 54, and side surfaces 27 of each projection 23 are side surfaces 39 of every other projection 34 and side surfaces 58 of every other projection 54. Further, the side surface 28 of each protrusion 23 faces the side surface 38 of every other protrusion 34 and the side surface 59 of every other protrusion 54 with a gap 89 of distance (D−d) / 2. is doing.

  Each of the protrusions 34 and 54 of the rotation transmitting member terminates so that the envelope at the tip including the circular arc concave surfaces 36 and 56 forms a concentric circle having the same diameter, and the protrusion 74 of the intermediate interposed member 8 is The end envelope line including the arc concave surface 76 has the same diameter as the concentric circles of the end envelopes of the rotation transmission member protrusions 34 and 54 and terminates so as to form a concentric circle with the concentric circles.

  The coupling means 9 extends in the A direction from the inner end surface 44 of the outer diameter side base portion 32 toward the rotation transmitting member 7 and is integrally provided on the inner end surface 44 of the outer diameter side base portion 32 and is mutually connected in the R direction. Four coupling body portions 91 on the rotation transmission member 6 side arranged at equal angular intervals of 90 °, claw portions 92 integrally formed at the distal ends of the coupling body portions 91, and the outer diameter side base portion 52 Rotations that extend in the A direction from the inner end face 64 toward the rotation transmitting member 6 and are integrally provided on the inner end face 64 of the outer diameter side base 52 and are arranged at equal angular intervals of 90 ° in the R direction. The four coupling main body portions 93 on the transmission member 7 side, the claw portions 94 integrally formed at the distal ends of the respective coupling main body portions 93, and the outer peripheral surface 31 of the outer diameter side base portion 32 are each 90 ° in the R direction. In the R direction with equiangular spacing A plurality of shallow grooves 95 formed in the middle between the coupling main body portions 91 and provided with corresponding coupling main body portions 93 fitted therein, communicated with the respective shallow grooves 95 and opened at the outer end face 41. A deep groove 96 formed in the outer peripheral surface 31 of the outer diameter side base portion 32 and an outer peripheral surface 51 of the outer diameter side base portion 52 with an equal angular interval of 90 ° in the R direction and between the coupling main body portions 93 in the R direction. The outer peripheral surface 51 of the outer-diameter side base portion 52 is connected to each shallow groove 97 and opens at the outer end surface 61. Are formed at equal angular intervals of 45 ° in the R direction on the outer peripheral surface 71 of the intermediate outer diameter side base portion 72 and corresponding coupling body portions 91 and 93 are fitted and arranged. A plurality of grooves 99 I am.

  The pawl portion 92 is engaged with the outer diameter side base portion 52 in the deep groove 98 in a snap-fit manner, and the pawl portion 94 is engaged with the outer diameter side base portion 32 in the deep groove 96 in a snap-fit manner. The rotation transmitting members 6 and 7 are coupled so as not to be separated from each other across the intermediate interposed member 8 in the A direction.

  As described above, with respect to the intermediate interposed member 8 and the rotation transmitting members 6 and 7 that are coupled to each other by the coupling means 9 with the intermediate interposed member 8 interposed therebetween, each of the protrusions 13 of the coupling base 3 is , In the R direction, between one protrusion 34 and 54 of each pair of protrusions 34 and 54 of the rotation transmission members 6 and 7, that is, between every other protrusion 34 and 54, and between the intermediate interposed member 8. Of the pair of protrusions 74, the protrusions 74 are arranged between one protrusion 74, that is, between every other protrusion 74, and each of the protrusions 23 of the connection base 5 is a rotation transmitting member in the R direction. Between the projections 34 and 54 of the pair of projections 34 and 54 of 6 and 7, that is, between the remaining projections 34 and 54 and between the projections 74 of each pair of the intermediate interposed member 8. Between the other projections 74, that is, between every other projection 74. When the rotation shaft 2 and the rotation shaft 4 are rotated relative to each other in the R direction below a certain level, the protrusions 13 of the connecting base 3 have their side surfaces 17 and 18 in the R direction facing each other in the R direction. While making contact with the side surfaces 78 and 79 in the R direction of each protrusion 74, they are not in contact with the side surfaces 38 and 39 and 58 and 59 of the protrusions 34 and 54 of the rotation transmitting members 6 and 7 facing in the R direction. The projecting portions 23 of the connecting base 5 are in contact with the side surfaces 78 and 79 in the R direction of the projecting portions 74 of the intermediate interposed member 8 facing in the R direction at the side surfaces 27 and 28 in the R direction, respectively. On the other hand, the side surfaces 38 and 39 and 58 and 59 of the protrusions 34 and 54 of the rotation transmitting members 6 and 7 facing each other in the R direction are not in contact with each other.

  A shaft connection that is arranged between the rotary shaft 2 and the rotary shaft 4 so as to transmit the rotation of the rotary shaft 2 in the R direction to the rotary shaft 4 and connects the rotary shaft 2 and the rotary shaft 4 as two rotary shafts to each other. In the above-described electric power steering apparatus including the mechanism 1, when the steering wheel is manually operated by the driver, the rotation shaft 4 is rotated in the R direction, and the rotation of the rotation shaft 4 in the R direction is a gear (not shown). Is transmitted as a reciprocating motion to a drag link or the like via a transmission mechanism such as a steering force to a steering wheel (wheel). In the manual operation of the steering wheel by the driver, when the electric motor controlled by the detection signal from the torque detector that detects the torque applied to the steering wheel is operated, the rotary shaft 2 is rotated in the R direction, and The connecting base body via the pressing of the projection 74 in the R direction by the projection 13 based on the contact of the side surface 17 with the side surface 78 or the contact of the side surface 18 with the side surface 79 after the projection 74 is deformed in the R direction by the portion 13. 3 is transmitted to the projecting portion 23 of the connecting base body 5, thereby adding the rotational force in the R direction of the rotational shaft 2 to the rotational force in the R direction of the rotational shaft 4, and steering by the driver. It is designed to assist manual operation of the wheel.

  In the shaft coupling mechanism 1, either the state where the steering wheel is not manually operated by the driver and the rotating shaft 4 is not rotated in the R direction, or the state where the steering wheel is manually operated by the driver and the rotating shaft 4 is rotated in the R direction. Even in this state, when the relative rotation in the R direction of the rotating shaft 2 with respect to the rotating shaft 4 is a minute one within about half of the difference between the width D and the width d, the protrusion 74 is easily compressed and deformed. As a result, such a small relative rotation in the R direction of the rotating shaft 2 is hardly transmitted to the rotating shaft 4, and thus the impact and brush vibration when the electric motor is reversed via the shaft coupling mechanism 1 and the rotating shaft 4. The transmission of the steering wheel to the steering wheel can be reduced, and the steering feeling can be prevented from becoming uncomfortable. Further, after a certain amount of compression deformation of the protrusion 74, the contact of the side surface 17 with the side surfaces 39 and 58 or the contact with the side surfaces 38 and 59 Each creep of the protrusion 74 results from contact of the face 18 and contact of the side face 27 to the side faces 39 and 58 or contact of the side face 28 to the side faces 38 and 59 to prevent further compression deformation of the protrusion 74. And the contact between the side faces 17 and 18 and the side faces 27 and 28 and the side faces 78 and 79 in the R direction between the protrusions 13 and 23 and the protrusion 74 can be maintained over a long period of time. And the rotation shaft 2 are less likely to be loose in the R direction. The rotation transmission member 6 is rotated with respect to the rotation shaft 4 by rotating the rotation shaft 4 in the R direction by the manual operation by the driver of the steering wheel and rotating the rotation shaft 2 in the R direction by the operation of the electric motor. When the shaft 2 is to be rotated relative to the R direction to a certain value or more, that is, about half or more of the difference between the width D and the width d, the contact of the side surface 17 with the side surface 39 and the side surface 58 or the side surface 38 and the side surface 59. The rotation of the rotating shaft 2 in the R direction is applied to the rotating shaft 4 in response to the relative rotation of the protruding portion 23 in the R direction by the protruding portion 13 based on the contact of the side surface 18 with the surface 18. The rotation is transmitted to assist the rotation of the rotating shaft 4.

  As described above, according to the shaft coupling mechanism 1, the intermediate interposed member 8 disposed between the rotation transmission members 6 and 7 is disposed between the protrusions 34 and 54 of the rotation transmission members 6 and 7 in the A direction. And a protrusion 74 having a width D larger than the width d in the R direction of each of the protrusions 34 and 54, and each protrusion 74 of the intermediate interposed member 8 is connected to the rotation transmitting members 6 and 7. As a result of having a rigidity smaller than the rigidity of each of the protrusions 34 and 54, transmission of the rotation of the rotation shaft 2 in the R direction to the rotation shaft 4 is caused by elastic deformation of the protrusion 74 of the intermediate interposed member 8. Therefore, transmission of minute rotation in the R direction of the rotating shaft 2 to the rotating shaft 4 can be reduced or prevented by elastic deformation of the protrusion 74 of the intermediate interposed member 8 and a large R of the rotating shaft 2 relative to the rotating shaft 4 can be achieved. The transmission of relative rotation in the direction to the rotating shaft 4 is more than the protrusion 74 of the intermediate interposed member 8. The rotation transmission members 6 and 7 having high rigidity can be carried out as they are through the projections 34 and 54, and the rigidity of the rotation shaft 2 relative to the rotation shaft 4 is greater than a certain level in the R direction. In order that the protrusions 34 and 54 of the rotation transmission members 6 and 7 can prevent large elastic deformation of the protrusion 74 of the intermediate interposed member 8, a flexible and rigid resin material is used for the intermediate intermediate member 8. However, permanent deformation of the intermediate interposed member 8 due to creep can be reduced, and in addition, an annular intermediate outer diameter side base portion disposed between the outer diameter side base portions 32 and 52 of the rotation transmitting members 6 and 7 in the A direction. 72. Since each protrusion 74 of the intermediate interposed member 8 integrally extends in the radial direction from the inner peripheral surface 73 of 72 in the central direction, each protrusion 74 of the intermediate interposed member 8 can be firmly held. In addition, a pair of rotation transmission Since the members 6 and 7 are connected to each other via the coupling means 9, the assemblability can be improved and the pair of rotation transmitting members 6 and 7 can be separated from each other in the A direction due to elastic deformation of the intermediate interposed member 8. As a result, the spread of the pair of rotation transmission members 6 and 7 in the A direction can be kept constant, and therefore, the impact when the electric motor is reversed and the transmission of brush vibration to the steering wheel can be reduced and the rotation can be reduced. The backlash in the R direction between the shaft 2 and the rotating shaft 4 can be eliminated, the steering feeling can be made uncomfortable and the durability can be excellent and the characteristics can be stabilized.

  Further, the shaft coupling mechanism 1 in the above example is composed of one intermediate interposed member 8, but may instead be composed of two or more intermediate interposed members 8, and the rotation transmitting members 6 and 7. Each of these may also consist of more than one. Further, the protrusions 13 and 23 of the coupling bases 3 and 5, the protrusions 34 and 54 of the rotation transmitting members 6 and 7, the protrusion 74 of the intermediate interposed member 8, the coupling main body 91 of the coupling means 9, etc. It is not limited to.

It is a front view of a preferable example of the present invention. It is an exploded view of the example shown in FIG. It is an III-III arrow explanatory drawing of one connection base | substrate shown in FIG. It is IV-IV arrow explanatory drawing of the other connection base | substrate shown in FIG. It is a VV arrow explanatory drawing of one rotation transmission member shown in FIG. It is VI-VI arrow explanatory drawing of the one rotation transmission member shown in FIG. It is a VII-VII line arrow directional cross-sectional explanatory drawing of one rotation transmission member shown in FIG. It is a VIII-VIII line arrow directional cross-sectional explanatory drawing of one rotation transmission member shown in FIG. It is IX-IX arrow directional cross-section explanatory drawing of one rotation transmission member shown in FIG. It is XX arrow explanatory drawing of the other rotation transmission member shown in FIG. It is XI-XI arrow explanatory drawing of the other rotation transmission member shown in FIG. It is XII-XII arrow directional cross-sectional explanatory drawing of the other rotation transmission member shown in FIG. It is XIII-XIII arrow directional cross-sectional explanatory drawing of the other rotation transmission member shown in FIG. It is XIV-XIV arrow directional cross-sectional explanatory drawing of the other rotation transmission member shown in FIG. It is XV-XV arrow explanatory drawing of the intermediate interposition member shown in FIG. It is XV-XV arrow explanatory drawing of the intermediate interposition member shown in FIG. 2, the other connection base example, and the other connection base. FIG. 17 is a cross-sectional explanatory view taken along the line XVII-XVII of the intermediate interposed member, one connection base example, and one connection base shown in FIG. 16.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Axis connection mechanism 2 Rotating shaft 3 Connection base | substrate 4 Rotation shaft 5 Connection base | substrate 6, 7 Rotation transmission member 8 Intermediate | middle interposition member 9 Coupling means 11, 21 Base part 12, 22 Annular surface 13, 23 Projection part 31, 51, 71 32, 52 Outer diameter side base portion 33, 53 Inner peripheral surface 34, 54, 74 Protruding portion 35, 55, 75 Tip portion 36, 56, 76 Arc concave surface 38, 39, 58, 59, 78, 79 Side surface 47, 67, 87 Space 72 Middle outer diameter side base

Claims (7)

  A shaft coupling mechanism arranged between two rotating shafts to connect the two rotating shafts so as to transmit the rotation of one rotating shaft to the other rotating shaft, and a pair of rotation transmissions overlapped in the axial direction A member and an intermediate interposed member interposed between the pair of rotation transmission members, and each of the pair of rotation transmission members is separated from the annular outer diameter side base portion in the direction around the axis. And at least a pair of protrusions integrally extending radially from the inner peripheral surface of the outer diameter side base portion toward the central direction, and the intermediate interposed member is a pair of rotation transmissions in the axial direction. An annular intermediate outer diameter side base portion disposed between the outer diameter side base portions of the member, and an inner peripheral surface of the intermediate outer diameter side base portion integrally extending in the radial direction toward the center and each rotation Larger than the width of each protrusion of the transmission member in the direction around the axis Each of the pair of protrusions of the intermediate interposed member disposed between the pair of protrusions of the pair of rotation transmitting members in the axial direction is a rotation transmitting member. A shaft coupling mechanism having rigidity smaller than the rigidity of each protrusion and elastically deformable.   2. The shaft coupling mechanism according to claim 1, wherein the projecting portion of the intermediate interposed member is a free end at a distal end portion extending radially from the inner peripheral surface of the intermediate outer diameter side base portion toward the central direction.   3. The shaft according to claim 1, wherein each of the protrusions of the rotation transmitting member is a free end at a distal end portion extending radially from the inner peripheral surface of the outer diameter side base portion toward the central direction. 4. Linkage mechanism.   The respective protrusions of the rotation transmitting member and the protrusions of the intermediate interposed member are terminated so that the envelopes at the tips extending in the radial direction form concentric circles. Shaft coupling mechanism.   One connecting base connected to one rotating shaft and the other connecting base connected to the other rotating shaft are further provided. One connecting base is integrated with a base portion in the axial direction from the base portion. And the other connecting base includes a base and a protrusion integrally protruding in the axial direction from the base, and the protrusion of the one connecting base is One of the protrusions between the pair of protrusions of the pair of rotation transmitting members in the direction around the axis and between the pair of protrusions of the intermediate interposed member in the direction around the axis The projections of the other connecting base disposed between the other projections of the pair of rotation transmitting members in the direction around the axis and the middle in the direction around the axis 5. The apparatus according to claim 1, wherein the interposition member is disposed between the other protrusions of the pair of protrusions. Shaft coupling mechanism according to.   The protrusions of the one and the other connecting base are on their respective sides in the direction around the axis, and around the axis of the protrusion of the intermediate interposed member that faces in the direction around the axis when the relative rotation of the two rotation axes is less than a certain level. The side surfaces in the direction around the axis of the protrusions of the pair of rotation transmitting members facing in the direction around the axis are not in contact with each other when the rotation of the two rotation axes is below a certain level. 6. The shaft coupling mechanism according to claim 5, wherein the shafts are brought into contact with each other at a relative rotation of a predetermined value or more.   A shaft coupling mechanism for an electric power steering apparatus, wherein one rotating shaft is coupled to an output rotating shaft of an electric motor, and the other rotating shaft is coupled to a steering shaft of an automobile. The shaft coupling mechanism according to any one of claims 1 to 6, wherein the shaft coupling mechanism is configured as described above.

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