JP5846229B2 - Shaft coupling mechanism for electric power steering device - 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.

  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.

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

  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, wherein the pair of rotation transmission members are spaced apart from each other in the direction around the axis. It has at least a pair of protrusions extending in the radial direction, and the intermediate interposed member is disposed between the pair of protrusions of the pair of rotation transmitting members in the axial direction and around the axis of each pair of protrusions Each of the pair of protrusions of the intermediate interposed member has a rigidity smaller than the rigidity of the pair of protrusions of each pair of rotation transmitting members. A pair of rotations that are elastically deformable At least one of the reaches member has a bulging preventing means for preventing certain level of swelling in the radial direction of the free end face of the radial direction of the pair of projections of the intermediate interposed member.

  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 transmitting members in the axial direction and is wider than the width in the direction around the axis of each pair of protrusions. As a result of having a pair of protrusions having a large width, transmission of rotation of one rotation shaft to the other rotation shaft is performed via elastic deformation of the pair of protrusions of the intermediate interposed member. 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 the other of the large relative rotation of the one rotating shaft with respect to the other rotating shaft can be reduced. Transmission to the rotation shaft can be performed as it is through the pair of rotation transmission members having rigidity greater than that of the pair of protrusions of the intermediate interposed member, and the shaft center around the pair of protrusions of the intermediate intermediate member High rigidity in elastic deformation beyond a certain direction Since the pair of rotation transmission members can prevent a large deformation of the pair of protrusions of the intermediate interposed member, the intermediate intermediate member is made permanent by creep even when a resin material having flexibility and low rigidity is used for the intermediate intermediate member. In addition, at least one of the pair of rotation transmission members has a bulging prevention means for preventing the radial free end surfaces of the pair of protrusions of the intermediate interposed member from bulging in the radial direction. Therefore, the permanent deformation of the intermediate interposition member due to creep can also be reduced by this, and therefore, it can be coupled to the output rotation shaft of one of the rotation shafts, for example, the electric rotation shaft even after long-term use. Between the rotating shaft and the other rotating shaft, for example, the steering shaft connected to the steering wheel, is less likely to cause backlash in the direction around the shaft center. And reduces the transmission to the steering wheel, it is possible to provide a shaft coupling mechanism for an electric power steering apparatus that does not uncomfortable excellent steering feeling durability.

  Each of the pair of rotation transmitting members may include a central base portion having an annular outer peripheral surface, and an annular outer base portion that is concentric with the central base portion and is disposed radially outward. Well, in this case, each of the pair of protrusions of the pair of rotation transmitting members extends in a radial direction from the outer peripheral surface of the central base portion of the corresponding rotation transmitting member to the inner peripheral surface of the annular outer base portion, and the central base portion and It is good to be provided integrally with the outer base. In such a shaft coupling mechanism, the intermediate interposed member has a central base portion having an annular outer peripheral surface, and the pair of protrusions of the intermediate intermediate member are integrated with the outer peripheral surface of the central base portion of the intermediate intermediate member. And is extended radially outward from the outer peripheral surface of the central base portion of the intermediate interposed member, and the bulging prevention means is provided on the axial end surface of at least one outer base portion of the pair of rotation transmitting members. Even if it has an outer blocking protrusion that is provided integrally and blocks the bulging of the free end surface radially outward at the radially outer tip of the pair of protrusions of the intermediate interposed member, it replaces this. The intermediate interposed member includes an outer base portion having an annular inner peripheral surface, and the pair of protrusions of the intermediate intermediate member are integrated with the inner peripheral surface of the outer base portion of the intermediate intermediate member. And the outer base of the intermediate interposed member The bulge prevention means is integrally provided on the axial end face of at least one inner base portion of the pair of rotation transmitting members and is also provided in a pair of intermediate interposed members. You may have the inner side prevention protrusion which prevents the bulge to the radial direction inner side of the free end surface in the front-end | tip of the radial direction inner side of a protrusion.

  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.

FIG. 1 is a front view of a preferred example of the present invention. FIG. 2 is an exploded view of the example shown in FIG. 3 is an explanatory diagram taken along line III-III shown in FIG. FIG. 4 is an explanatory view taken along the line IV-IV shown in FIG. FIG. 5 is an explanatory view taken along line VV shown in FIG. 6 is an explanatory view taken along line VI-VI shown in FIG. FIG. 7 is a sectional view taken along line VII-VII shown in FIG. FIG. 8 is a sectional view taken along line VIII-VIII shown in FIG. 9 is a cross-sectional explanatory view taken along line I-IX shown in FIG. 10 is an explanatory view taken along line XX in FIG. 11 is an explanatory diagram taken along line XI-XI in FIG. 12 is a cross-sectional explanatory view taken along line XII-XII shown in FIG. 13 is an explanatory cross-sectional view taken along line XIII-XIII shown in FIG. FIG. 14 is a cross-sectional explanatory view taken along line XIX-XIX shown in FIG. FIG. 15 is an explanatory view taken along line XV-XV of the intermediate interposed member shown in FIG. FIG. 16 is an explanatory diagram of a state in which the intermediate interposed member is attached to the rotation transmission member in the example illustrated in FIG. 1. 17 is a cross-sectional explanatory view taken along the line XVI-XVI shown in FIG. FIG. 18 is an explanatory diagram of another preferred example of the intermediate interposed member in 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 shaft coupling mechanism 1 for the electric power steering apparatus according to the present embodiment includes a coupling base 3 coupled to the rotating shaft 2, a coupling base 5 coupled to the rotating shaft 4, and an axial direction A. A pair of rotation transmission members 6 and 7, an intermediate interposed member 8 interposed between the pair of rotation transmission members 6 and 7, and a coupling means 9 for coupling the pair of rotation transmission members 6 and 7 to each other. The two rotation shafts are arranged between the two rotation shafts 2 and 4 so as to transmit the rotation around the axis O of the rotation shaft 2, that is, the rotation in the R direction to the rotation shaft 4. 2 and 4 are connected.

  The rotating shaft 2 is a rotating shaft on the electric motor side of the electric power steering apparatus, and is connected to the output rotating shaft of the electric motor.

  The rigid connecting base 3 is integrally protruded from the annular base 11 and one annular surface 12 of the base 11 in the axial direction A and spaced apart from each other at an equal angular interval of 90 ° in the R direction. In addition, four protrusions 13 having a triangular prism shape and through-holes 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 an operation (steering) of the steering wheel.

  The rigid connecting base 5 is integrally protruded from the annular base 21 and one annular surface 22 of the base 21 in the axial direction A and is spaced apart from each other at an equal angular interval of 90 ° in the R direction. The four triangular prism-shaped protrusions 23 and the through holes 24 into which the rotating 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 central base portion 32 having the annular outer peripheral surface 31 at equal angular intervals in the R direction. And eight projecting portions 33 extending in the radial direction, concentric with the central base portion 32 and arranged radially outward, and having an annular inner peripheral surface 34 and an annular outer peripheral surface 35. And an annular outer base 36.

  Each of the protrusions 33 arranged at equal angular intervals of 45 ° in the R direction extends in the radial direction from the outer peripheral surface 31 of the central base portion 32 to the inner peripheral surface 34 of the outer base portion 36, and the outer peripheral surface of the central base portion 32. 31 and an inner peripheral surface 34 of the outer base 36, and have side surfaces 38 and 39 as a pair of rigid rotation transmission surfaces in the R direction. 36 are connected to each other.

  Outer end surfaces 41, 42, and 43, which are one end surfaces in the axial direction A of the central base 32, the respective protrusions 33, and the outer base 36, are flush with each other, and the central base 32, the respective protrusions 33, and the outer base 36 The inner end surfaces 44, 45 and 46, which are the other end surfaces in the A direction, are also flush with each other, and the outer peripheral surface 31 of the central base 32, the inner peripheral surface 34 of the outer base 36 and the side surfaces 38 and 39 of the protrusion 33 are The eight triangular prism-shaped through holes 47 into which the protrusion 13 and the protrusion 23 are inserted are defined.

  A rigid rotation transmission member 7 formed integrally from polyacetal resin, polyamide resin or the like is formed in the same manner as the rotation transmission member 6, and has an annular central base 52 having an annular outer peripheral surface 51, Eight protrusions 53 that are spaced apart from each other at equal angular intervals in the R direction and that extend in the radial direction, and are concentric with the central base 52 and arranged radially outward, and have an annular inner periphery And an annular outer base 56 having a surface 54 and an annular outer peripheral surface 55.

  Each of the protrusions 53 arranged at equal angular intervals of 45 ° in the R direction extends in the radial direction from the outer peripheral surface 51 of the central base portion 52 to the inner peripheral surface 54 of the outer base portion 56, and the outer peripheral surface of the central base portion 52. 51 and an inner peripheral surface 54 of the outer base 56, and have side surfaces 58 and 59 as a pair of rigid rotation transmission surfaces in the R direction. 56 are connected to each other.

  Outer end surfaces 61, 62, and 63, which are one end surfaces in the A direction of the central base 52, the respective protrusions 53, and the outer base 56, are flush with each other. The inner end faces 64, 65 and 66 which are the other end faces in the direction are also flush with each other, and the outer peripheral face 51 of the central base 52, the inner peripheral face 54 of the outer base 56 and the side faces 58 and 59 of the projection 53 are Eight triangular prism-shaped through holes 67 into which the protrusions 13 and 23 are inserted are defined.

  The intermediate interposed member 8 disposed between the rotation transmitting members 6 and 7 has a rigidity smaller than that of the rotation transmitting members 6 and 7 and can be elastically deformed, and rubber elasticity such as urethane rubber, silicone rubber, polyester elastomer or the like. The intermediate interposed member 8 is integrally formed with an annular central base 73 having an annular inner peripheral surface 71 and an outer peripheral surface 72 that are concentric with each other, and an outer peripheral surface 72 of the central base 73. And eight protrusions 74 extending radially outward from the outer peripheral surface 72 of the central base 73.

  The protrusions 74 that are the same as the total number of the protrusions 33 and 53 of the rotation transmitting members 6 and 7 and are spaced apart from each other at equal angular intervals of 45 ° in the R direction are axially In A, the pair of rotation transmitting members 6 and 7 are disposed between the corresponding pair of protrusions 33 and 53 and have a width D larger than the width d of the protrusions 33 and 53 in the R direction. Each of the protrusions 74 having rigidity smaller than the rigidity of the protrusions 33 and 53 of the rotation transmitting members 6 and 7 and elastically deformable has side surfaces 75 and 76 in the R direction. The side surfaces 75 of the projections 74 are alternately in contact with the side surfaces 17 of the projections 13 and the side surfaces 27 of the projections 23 in the R direction, and the side surfaces 76 of the projections 74 correspond to the side surfaces 28 and 28 of the projections 23. The side surfaces 18 of the protrusions 13 are alternately in contact with each other in the R direction.

  The intermediate interposed member 8 is flat at the surfaces 77 and 78 facing the flat inner end surfaces 44, 45 and 46 and the inner end surfaces 64, 65 and 66 in the A direction of the rotation transmitting members 6 and 7, respectively. 77 is slidably in contact with the inner end surfaces 44, 45 and 46, and the surface 78 is slidably in contact with the inner end surfaces 64, 65 and 66.

  The coupling means 9 extends in the axial direction A from the inner end surface 46 of the outer base portion 36 toward the rotation transmitting member 7 and is integrally provided on the inner end surface 46 of the outer base portion 36 and is 90 ° in the R direction. Rotates from four coupling body portions 81 on the side of the rotation transmission member 6 arranged at equal angular intervals, a claw portion 82 formed integrally at the tip of each coupling body portion 81, and an inner end surface 66 of the outer base portion 56. The four on the rotation transmission member 7 side which extend in the axial direction A toward the transmission member 6 side and are provided integrally with the inner end surface 66 of the outer base 56 and arranged at equal angular intervals of 90 ° in the R direction. A plurality of coupling main body portions 83, pawl portions 84 formed integrally at the distal ends of the respective coupling main body portions 83, and the outer peripheral surface 35 of the outer base portion 36 at equal angular intervals of 90 ° in the R direction and in the R direction. Join A plurality of shallow grooves 85 formed in the middle between the body portions 81 and fitted with corresponding coupling main body portions 83, and communicated with the respective shallow grooves 85 and opened at the outer end face 43 to be outside. A deep groove 86 formed in the outer peripheral surface 35 of the base portion 36 and an outer peripheral surface 55 of the outer base portion 56 are formed at equal angular intervals of 90 ° in the R direction and in the middle between the coupling main body portions 83 in the R direction. And a plurality of shallow grooves 87 arranged with corresponding coupling body portions 81 fitted therein, and deep grooves 88 communicating with each shallow groove 87 and opening at the outer end face 63 and formed on the outer peripheral surface 55 of the outer base 56. It has.

  The claw portion 82 is snap-fit engaged with the outer base portion 56 in the deep groove 88, and the claw portion 84 is snap-fit engaged with the outer base portion 36 in the deep groove 86, whereby the rotation transmitting member 6 is engaged. And 7 are coupled so as not to be separated from each other across the intermediate interposed member 8 in the axial direction A.

  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 the projections 33 and 53 of each pair of the projections 33 and 53 of the rotation transmitting members 6 and 7, that is, between every other projections 33 and 53 and 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. 7 between the projections 33 and 53 of each pair, between the other projections 33 and 53, that is, between the remaining projections 33 and 53 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 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 are protruded from the protrusions of the intermediate interposed member 8 facing in the R direction at their side surfaces 17 and 18 in the R direction. The side surfaces 75 and 76 in the R direction of the portion 74 are in contact with each other, while the side surfaces 38 and 39 and 58 and 59 of the protrusions 33 and 53 of the rotation transmitting members 6 and 7 facing in the R direction are not in contact with each other. The protrusions 23 of the connecting base 5 are in contact with the side surfaces 75 and 76 in the R direction of the respective protrusions 74 of the intermediate interposed member 8 facing in the R direction at the respective side surfaces 27 and 28 in the R direction. On the other hand, the side surfaces 38 and 39 and 58 and 59 of the protrusions 33 and 53 of the rotation transmitting members 6 and 7 facing each other in the R direction are not in contact with each other.

  At least one of the pair of rotation transmission members 6 and 7, in this example, the pair of rotation transmission members 6 and 7 is more than a certain amount in the radial direction of the free end surface 91 in the radial direction of each protrusion 74 of the intermediate interposed member 8. Bulging prevention means 92 is provided on the inner end faces 46 and 66 in the A direction of the outer base portions 36 and 56 of the pair of rotation transmitting members 6 and 7, respectively. A pair of rotations with outer blocking protrusions 93 and 94 that are integrally provided and prevent the free end surface 91 from bulging outward in the radial direction at the radially outer tip of each protrusion 74 of the intermediate interposed member 8. The center base portions 32 and 52 of the transmission members 6 and 7 are integrally provided on the inner end surfaces 44 and 64 in the A direction, and the free end surface 91 bulges outward in the radial direction by the outer blocking protrusions 93 and 94. In the middle of the intermediate interposed member 8 in blocking Annular bulge prevention auxiliary projections 95 and 96 that prevent the bulging of the portion 73 radially inward and assist the outer prevention protrusions 93 and 94 to prevent the free end surface 91 from bulging outward in the radial direction; have.

  The outer blocking protrusion 93 extending from the inner end face 46 toward the outer blocking protrusion 94 in the A direction and contacting the A direction top surface 98 of the outer blocking protrusion 94 at the top surface 97 in the A direction has a corresponding It has a radially inner surface 100 facing the free end surface 91 with a gap 99 of a predetermined width with respect to the free end surface 91 of the protrusion 74, and extends from the inner end surface 66 toward the outer blocking protrusion 93 in the A direction. The outer blocking projection 94 has a radial inner surface 101 facing the free end surface 91 with a gap 99 having a predetermined width with respect to the free end surface 91 of the corresponding projection 74.

  An annular shape extending from the inner end face 44 toward the bulging prevention auxiliary protrusion 96 in the A direction and contacting the top surface 106 of the bulging prevention auxiliary protrusion 96 in the A direction at the top surface 105 in the A direction. The bulge prevention auxiliary protrusion 95 has an annular radially outer peripheral surface 107 that is in contact with the inner peripheral surface 71 of the central base 73 of the intermediate interposed member 8, and bulges from the inner end surface 64 in the A direction. An annular bulge prevention auxiliary protrusion 96 extending toward the protrusion prevention auxiliary protrusion 95 is an annular radial outer peripheral surface that is in contact with the inner peripheral surface 71 of the central base 73 of the intermediate interposed member 8. 108.

  The bulging prevention means 92 bulges outward of the free end surface 91 of the projection 74 in the radial direction when the projection 74 is expanded in the radial direction due to the compressive deformation of the projection 74 in the R direction. Further contact of the outer blocking protrusions 93 and 94 with the inner surfaces 100 and 101 prevents further protrusion 74 from bulging outwardly in the radial direction of the free end surface 91.

  When the intermediate interposed member 8 that does not have the central circular hole 111 defined by the inner peripheral surface 71 is used, the bulging prevention auxiliary protrusions 95 and 96 can be omitted.

  A support shaft integrally extended from the rotary shaft 2 or the rotary shaft 4 is inserted into the central circular hole 111 of the intermediate interposing member 8 and the central circular holes 112 and 113 of the rotation transmitting members 6 and 7 with such a support shaft. If necessary, more reliable center positioning of the intermediate interposed member 8 and the rotation transmitting members 6 and 7 may be performed, but if this center positioning is not performed, the intermediate interposed member without the central circular holes 111, 112, and 113. 8 and the rotation transmission members 6 and 7 may be used.

  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 projecting portion 74 in the R direction by the projecting portion 13 based on the contact of the side surface 17 with the side surface 75 or the contact of the side surface 18 with the side surface 76 after the projecting portion 74 is deformed in the R direction. 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 38 and 59 or the contact with the side surfaces 39 and 58 can be reduced. As a result of the contact of the face 18 and the contact of the side face 27 with the side faces 38 and 59 or the contact of the side face 28 with the side faces 39 and 58, further compression deformation of the protrusion 74 can be suppressed. And the contact between the side faces 17 and 18 and the side faces 27 and 28 and the side faces 75 and 76 in the R direction between the protrusions 13 and 23 and the protrusion 74 can be maintained for 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 by a certain amount or more, that is, about half or more of the difference between the width D and the width d, the side surface 17 contacts the side surface 38 and the side surface 59 or the side surface 39 and the side surface 58. 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 33 and 53 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 of each of the protrusions 33 and 53 in the R direction, 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 33 and 53, 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 protrusions 33 and 53, and the rotation shaft 2 has a large rigidity in the relative rotation in the R direction of the rotation shaft 2 with respect to the rotation shaft 4. In order that the protrusions 33 and 53 of the rotation transmitting members 6 and 7 can prevent the elastic deformation of the protrusion 74 of the intermediate interposed member 8, a resin material that is flexible and has low rigidity is used for the intermediate interposed member 8. However, permanent deformation of the intermediate interposed member 8 due to creep can be reduced, and in addition, since the pair of rotation transmitting members 6 and 7 are connected to each other via the coupling means 9, the assemblability can be improved. It is possible to eliminate the mutual separation of the pair of rotation transmission members 6 and 7 in the A direction due to elastic deformation of the intermediate interposed member 8, and to suppress the spread of the pair of rotation transmission members 6 and 7 in the A direction constant. Electric motor In addition to reducing the impact at the time of reversal and the transmission of brush vibration to the steering wheel, it can eliminate the play in the R direction between the rotating shaft 2 and the rotating shaft 4, and makes the steering feel uncomfortable and has excellent durability Can be stable.

  In addition, according to the shaft coupling mechanism 1, the rotation transmitting members 6 and 7 have the bulging prevention means 92 for preventing the radial free end surface 91 of the protrusion 74 of the intermediate interposed member 8 from bulging in the radial direction. Therefore, the permanent deformation of the intermediate interposed member 8 due to creep can be reduced by this, and therefore, the R direction between the rotating shaft 2 and the rotating shaft 4 can be reduced even during long-term use. Providing a shaft coupling mechanism for an electric power steering device that is less likely to cause backlash, and that can reduce the impact of the electric motor when it is turned over and reduce the transmission of brush vibration to the steering wheel, making the steering feel uncomfortable. can do.

In the shaft coupling mechanism 1 of the above example, the bulging prevention means 92 is configured by the outer blocking protrusions 93 and 94 and the bulging prevention auxiliary protrusions 95 and 96, but the outer blocking protrusions 93 and 94 are omitted. The bulge prevention means 92 may be configured with the bulge prevention auxiliary protrusions 95 and 96 as inner prevention protrusions. In this case, the intermediate interposed member 8 is formed in an annular inner shape as shown in FIG. The outer base 123 having the peripheral surface 121 and the outer peripheral surface 122 and the inner peripheral surface 121 of the outer base 122 are integrally provided separately from each other at equal angular intervals of 45 ° in the R direction. Eight protrusions 74 extending radially inward from the inner peripheral surface 121 of the base 123, and the coupling body portions 81 and 83 of the coupling means 9 are fitted and grooves 124 formed on the outer peripheral surface 122. The inner bases 32 and 5 may be configured. The bulging preventing auxiliary protrusion 95 and 96 of the inner end surface 44 and 64 as the inner blocking protrusion having an annular outer surface with are integrally provided, the radially inner projections 74 of the intermediate interposed member 8 The free end surface 125 made of an arcuate concave surface at the tip of the rim is prevented from bulging radially inward.

  When the intermediate interposed member 8 shown in FIG. 18 is used, the intermediate interposed member 8 is moved in the A direction between the rotation transmitting member 6 and the inner end surface 46 of the outer base portion 36 and the inner end surface 66 of the outer base portion 56 with the outer base portion 123 interposed therebetween. The shaft coupling mechanism 1 is preferably arranged between the seven.

  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 33 and 53 of the rotation transmitting members 6 and 7, the protrusion 74 of the intermediate interposed member 8, the coupling main body 81 of the coupling means 9, etc. It is not limited to.

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 92 Swelling prevention means 93, 94 Outer prevention protrusion

Claims (5)

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 Each of the pair of rotation transmission members is spaced apart from each other in the direction around the axis and extends in the radial direction. and at least has a pair of projections, the intermediate interposed member, the direction around the axis in the projection of each pair together is disposed between a pair of projections in our Keru pair of rotation transmitting members in the axial direction Each of the pair of protrusions of the intermediate interposed member has a rigidity smaller than the rigidity of the pair of protrusions of each pair of rotation transmitting members. Of the pair of rotation transmission members At least one has bulging prevention means for preventing bulging of the radial free end surfaces of the pair of protrusions of the intermediate interposed member beyond a certain level in the radial direction. A central base portion having an annular outer peripheral surface, and an annular outer base portion that is concentric with the central base portion and disposed radially outward, and each pair of rotation transmitting members The protrusion extends in a radial direction from the outer peripheral surface of the central base portion of the corresponding rotation transmitting member to the inner peripheral surface of the annular outer base portion, and is provided integrally with the central base portion and the outer base portion. And an annular central base portion having an annular outer peripheral surface, and the pair of protrusions of the intermediate interposed member are integrally provided on the outer peripheral surface of the central base portion of the intermediate interposed member and the intermediate Extends radially outward from the outer peripheral surface of the central base of the interposed member, and bulges The stop means is provided integrally with the axial end surface of at least one outer base portion of the pair of rotation transmitting members, and has a diameter of the free end surface at the radially outer tip of the pair of protrusions of the intermediate interposed member. The outer blocking protrusions that prevent outward bulging and the axially inner end surfaces of the central bases of the pair of rotation transmitting members are integrally provided, and the radial direction of the free end surface by the outer blocking protrusions An annular bulge prevention that prevents the bulging of the central base portion of the intermediate interposition member in the radially inner direction and assists the bulging of the free end face in the radially outward direction by the outer blocking protrusion in preventing the bulging outward. A shaft coupling mechanism having an auxiliary projection. 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 Each of the pair of rotation transmission members is spaced apart from each other in the direction around the axis and extends in the radial direction. and at least has a pair of projections, the intermediate interposed member, the direction around the axis in the projection of each pair together is disposed between a pair of projections in our Keru pair of rotation transmitting members in the axial direction Each of the pair of protrusions of the intermediate interposed member has a rigidity smaller than the rigidity of the pair of protrusions of each pair of rotation transmitting members. Of the pair of rotation transmission members At least one has bulging prevention means for preventing bulging of the radial free end surfaces of the pair of protrusions of the intermediate interposed member beyond a certain level in the radial direction. A central base portion having an annular outer peripheral surface, and an annular outer base portion that is concentric with the central base portion and disposed radially outward, and each pair of rotation transmitting members The protrusion extends in a radial direction from the outer peripheral surface of the central base portion of the corresponding rotation transmitting member to the inner peripheral surface of the annular outer base portion, and is provided integrally with the central base portion and the outer base portion. The outer base portion having an annular inner peripheral surface, and the pair of protrusions of the intermediate interposed member are integrally provided on the inner peripheral surface of the outer base portion of the intermediate intermediate member and the intermediate intermediate member The bulging prevention means extends radially inward from the inner peripheral surface of the outer base of the member. And a free end surface formed integrally with an axial end surface of at least one inner base portion of the pair of rotation transmitting members and formed by an arcuate concave surface at a radially inner end of the pair of protrusions of the intermediate interposed member The shaft coupling mechanism which has the inner side prevention protrusion which has the annular | circular shaped outer surface which prevents the swelling to the radial inside.   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 The shaft linkage according to claim 1 or 2 arranged between the other projections of a pair of projections of an interposition member. Mechanism.   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. 4. The shaft coupling mechanism according to claim 3, wherein the shafts are brought into contact with each other at a relative rotation of a certain level or more of both rotating shafts.   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 4, wherein the shaft coupling mechanism is configured as described above.

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