JP2014040868A - Shaft connecting mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shaft connecting mechanism capable of reducing impact when an electric motor is reversed, and transmission of brush vibration to a steering wheel, excellent in durability, preventing discomfort of steeling feeling, and solving a wear-out problem due to repeated expansion and contraction, and a swelling problem in the shaft direction due to compression, when elastic deflective bending deformation is used.SOLUTION: A shaft connecting mechanism 1 includes: a connection base 3 connected to a rotating shaft 2; a connection base 5 connected to a steering shaft 4; a pair of outer interposed connecting members 6 and 7 disposed between the rotating shaft 2 and the steering shaft 4 in an A direction through both connection bases 3 and 5, and transmitting the rotation in an R direction to the steering shaft 4; and an intermediate interposed connecting member 8 disposed between the pair of outer interposed connection members 6 and 7.

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 power steering apparatus easily adds a rotational force based on rotation of an output rotation shaft of an electric motor to a rotational force based on rotation of a manually operated steering wheel (handle) to facilitate manual steering of the steering wheel. In such an electric 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 connected via a shaft connecting mechanism (coupling). doing.

  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 an elastic spacer such as rubber or soft resin in the shaft coupling mechanism. However, emphasis is placed on reducing impact and vibration. If the spacer is made more flexible, the flexible spacer is likely to be creep-deformed. Therefore, the permanent deformation of the spacer due to the repeated load on the spacer causes a backlash in the shaft coupling mechanism. While the steering feel may become uncomfortable, if the spacer is made hard with an emphasis on durability, the steering feel will be improved in terms of no play, contrary to the above. Shock transmitted as the steering wheel mentioned above, the steering feeling becomes uncomfortable vibration.

  Therefore, a pair of rotation transmitting members, an intermediate intermediate connecting connecting member disposed between the pair of rotation transmitting members, one connecting base connected to one rotating shaft, and the other rotating shaft are connected. A steering shaft connected to, for example, a steering wheel, which is a rotating shaft connected to an output rotating shaft of an electric motor, for example. The backlash in the direction around the shaft center is unlikely to occur between the shaft and the impact when the electric motor is reversed, and the transmission of brush vibrations to the steering wheel can be reduced. A shaft coupling mechanism for an electric power steering device that does not make it uncomfortable has also been proposed (see Patent Document 4).

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

  By the way, in such a proposed shaft coupling mechanism, the above-mentioned effect is produced mainly by utilizing the compression elastic deformation of the intermediate intervening coupling member. However, the intermediate intervening coupling member is made of a compressible material such as rubber. As a result of being formed with an elastic material, there are problems of sag due to repeated expansion and contraction and problems of axial swelling due to compression.

  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. A backlash in the rotational direction is unlikely to occur between the rotating shaft and the steering shaft connected to the steering wheel, for example, and it is possible to reduce impact when the electric motor is reversed and transmission of brush vibration to the steering wheel. To provide a shaft coupling mechanism that has excellent durability and does not make the steering feeling uncomfortable, and that does not cause problems of sag due to repeated expansion and contraction and axial bulging due to compression in order to use elastic bending and deformation. It is in.

  The shaft coupling mechanism according to the present invention, which is arranged between two rotating shafts and couples the two rotating shafts via a pair of intervening coupling members that transmit the rotation of one rotating shaft to the other rotating shaft, Responds to the relative rotation of the rotating shaft in the direction around the axis with a resistance in the direction around the axis accompanied by the elastic bending bending deformation of one of the pair of interposed connecting members. On the other hand, the other intervening connecting member of the pair of intervening connecting members is made to be unresponsive, and the bending of one intervening connecting member is not allowed with respect to the relative rotation of the two rotating shafts in a direction around the axis thereof. Direction around the axis based on inflexibility consisting of resistance in the direction around the axis based on bending deformation and elastic bending and bending deformability smaller than the elastic bending and bending deformability of one interposed connecting member of the other interposed connecting member Respond with the resistance of others Through the intervening connecting member is adapted to transmit the rotation of one rotating shaft to the other rotating shaft.

  According to the shaft coupling mechanism according to the present invention, the relative rotation of the two rotating shafts in the direction around the axial center is less than a certain amount in the direction around the axial center accompanied by the elastic bending bending deformation of one intervening coupling member. While responding with resistance, the other intervening coupling member of the pair of intervening coupling members is made non-responsible, so that the impact at the time of reversal of the electric motor and the transmission of brush vibration to the steering wheel can be reduced. With respect to relative rotation of the rotation shaft in a direction around the axis, the resistance in the direction around the axis based on the bending bending deformation of one interposition connection member and one interposition connection member of the other interposition connection member In response to the resistance in the direction around the axis based on the inflexibility, which is smaller than the elastic bending / deformability, the rotation of one rotating shaft is caused via the other intervening connecting member. The other rotation axis Since it is designed to transmit, it is possible to suppress the deterioration of the bending and bending deformability of one of the intervening connecting members, and the rotating shaft connected to one rotating shaft, for example, the output rotating shaft of an electric motor, even after long-term use And the other rotating shaft, for example, the steering shaft connected to the steering wheel is less likely to cause backlash in the rotational direction, has excellent durability and does not make the steering feeling uncomfortable, and the elastic deflection of one intervening connecting member Since bending deformation is used, the problem of sag due to repeated expansion and contraction and the problem of swelling in the axial direction are not caused.

  The present invention includes one intervening connecting member having elastic bending / deformability and the other inflexible intervening connecting member having elastic bending / deformability smaller than the elastic bending / deformability of the intervening connecting member. It is only necessary to have at least a pair of intervening connecting members, and in a preferred example, there is one intervening connecting member having flexibility of bending and deformability, and a pair of inflexibility arranged with the intervening connecting members sandwiched in the axial direction. Interposing connecting members.

  In a preferred example, the apparatus further includes one connection base connected to one rotation shaft and the other connection base connected to the rotation shaft of the other rotation shaft. It arrange | positions between the connection base | substrates.

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

  In the case of an electric power steering device, the rotation of the output rotation shaft of the electric motor via the shaft coupling mechanism of the present invention is further performed by steering the automobile via a worm gear mechanism comprising a worm shaft and a worm wheel meshing with the worm shaft. It may be transmitted to the shaft.

  In a preferred example of the present invention, one of the intervening connecting members includes a first base and at least a pair of elastic flexure bending deformable protrusions provided integrally and radially projecting from the first base. The other intervening connecting member is provided with a second base portion and a radially projecting integral one piece on the second base portion, and a pair of elastic flexures of one intervening connecting member are freely deformable. Bending rigidity that is smaller than the protrusion, that is, bending rigidity in the direction around the axis that is larger than the bending rigidity in the direction around the axis of the pair of elastic bending-deformable protrusions of one interposition connecting member And at least a pair of inflexible protrusions.

  In a preferred example, each of the pair of elastic bending-deformable protrusions has a width in the direction around the axis that is greater than the width in the direction around the axis of the inflexible protrusion.

  Another shaft coupling mechanism of the present invention, which is arranged between two rotating shafts so as to transmit the rotation of one rotating shaft to the other rotating shaft and connects the two rotating shafts, is a pair of outer intervening connecting members. An intermediate intervening connecting member disposed between the pair of outer intervening connecting members, one connecting base connected to one rotating shaft, and the other connecting base connected to the other rotating shaft Each of the pair of outer interposed connecting members has at least a pair of inflexible protrusions that are spaced apart from each other in the direction around the axis and extend in the radial direction. The connecting member is disposed between the pair of inflexible protrusions of the pair of outer intervening connecting members in the axial direction and has a width larger than the width in the direction around the axis of each pair of inflexible protrusions. Has a pair of elastic flexural bendable protrusions, one and the other Each of the connection bases includes a base and a protrusion integrally protruding in the axial direction from one surface of the base in the axial direction. The protrusion of the one connection base is a direction around the axis. Between a pair of inflexible protrusions of each pair of inflexible protrusions of a pair of outer intervening connection members and between a pair of elastically flexible bending deformable protrusions of an intermediate interposition connection member in the direction around the axis Between the pair of inflexible protrusions of the pair of outer intervening connecting members in the direction around the axis. Between the other inflexible protrusions and between the pair of elastic flexible bending deformable protrusions of the intermediate interposing connecting member in the direction around the axis, the other elastic flexible bending deformable protrusions are arranged. .

  Still another shaft coupling mechanism according to the present invention, which is arranged between two rotary shafts so as to transmit the rotation of one rotary shaft to the other rotary shaft and connects the two rotary shafts, An intermediate connecting member disposed between the pair of outer intermediate connecting members, one connecting base connected to one rotating shaft, and the other connected to the other rotating shaft. Each of the pair of outer intervening coupling members has at least a pair of elastic bending-deformable protrusions that are spaced apart from each other in the direction around the axis and extend in the radial direction. The intermediate interposition connecting member is disposed between the pair of elastic flexible bending deformable protrusions of the pair of outer intermediate connecting members in the axial direction, and the shaft center of each pair of elastic flexible bending deformable protrusions One with a width smaller than the width in the surrounding direction The one and the other connecting bases each include a base and a protrusion integrally protruding in the axial direction from one surface of the base in the axial direction. The protrusion of one of the connection bases is one elastic bending-deformable protrusion between each pair of elastic bending-deformable protrusions of the pair of outer intervening connecting members in the direction around the axis and around the axis. Between the inflexible protrusions of the pair of inflexible protrusions of the intermediate intervening connecting member in the direction of the direction, and the protrusions of the other connecting base are a pair of outer sides in the direction around the axis Among the pair of elastic flexible bending deformable protrusions of the intervening connecting member, between the other elastic flexible bending deformable protrusions and between the pair of inflexible protrusions of the intermediate intermediate connecting member in the direction around the axis. Between the other inflexible protrusions.

  Even in such a shaft coupling mechanism of the present invention, a pair of outer intervening couplings having at least a pair of inflexible protrusions or elastically flexible bending deformable protrusions that are separated from each other in the direction around the axis and extend in the radial direction. For each of the members, the intermediate interposition connecting member is disposed between the pair of inflexible protrusions or the elastically flexible bending deformable protrusions of the pair of outer intervening connection members in the axial direction and each pair of inflexibility. In order to have a pair of elastic flexible bending deformable protrusions or inflexible protrusions having a width larger or smaller than the width in the direction around the axis of the elastic protrusion or elastic bending bending deformable protrusion, Even in long-term use, the rotational direction 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 The backlash is less likely to occur, the durability is excellent, and the steering feeling is not made uncomfortable, and the elastic bending and deformation of one of the interposing connecting members is used, so that the problem of sag due to repeated expansion and contraction and the problem of swelling in the axial direction do not occur. .

  In any of the shaft coupling mechanisms of the present invention, each of the pair of elastic flexible bending deformable protrusions may have a slit extending in the radial direction in order to obtain preferable elastic flexible bending deformability. The slit is opened at the respective radial front ends of the pair of elastic bending / deformable protrusions, but is closed at the respective radial front ends of the pair of elastic bending / deformable protrusions. Moreover, you may have the width | variety of the direction of the surroundings of an axial center which becomes large gradually as it goes to the front end surface of an elastic bending bending deformable protrusion from the base part of an elastic bending bending deformable protrusion.

  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. The backlash in the rotation direction is not likely to occur, and the impact when the electric motor is reversed and the transmission of brush vibrations to the steering wheel can be reduced. Since the bending deformation is used, it is possible to provide a shaft coupling mechanism that does not cause the problem of sag due to repeated expansion and contraction and the problem of axial swelling due to compression.

FIG. 1 is an explanatory front view of a preferred example of an embodiment of the present invention. FIG. 2 is an explanatory diagram on the right side of the connecting base connected to the rotating shaft of the example shown in FIG. FIG. 3 is an explanatory left side view of the connecting base connected to the steering shaft of the example shown in FIG. 4 is a cross-sectional explanatory view taken along the line IV-IV in the example shown in FIG. FIG. 5 is a cross-sectional explanatory view taken along the line VV in the example shown in FIG. 1. 6 is a cross-sectional explanatory view taken along the line VI-VI in the example shown in FIG. 7A and 7B are explanatory views of the outer intervening connecting member in the example shown in FIG. 1, wherein FIG. 7A is a side explanatory view, and FIG. 7B is a front explanatory view. FIG. 8 is an explanatory view of an intermediate interposition connecting member in the example shown in FIG. 1, wherein (a) is a side explanatory view and (b) is a front explanatory view. FIG. 9 is an explanatory front view of the overlapped outer and intermediate intervening connecting members in the example shown in FIG. 1. FIG. 10 is a cross-sectional explanatory view corresponding to FIG. 4 of another preferred example of the embodiment of the present invention.

  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 9, a shaft coupling mechanism 1 for an electric power steering apparatus according to this embodiment includes a coupling base 3 coupled to a rotating shaft 2, and a coupling base 5 coupled to a steering shaft 4 serving as a rotating shaft. The axial direction of the rotary shaft 2 and the steering shaft 4 via both the connecting bases 3 and 5, that is, the direction around the axis of the rotary shaft 2 is arranged between the rotary shaft 2 and the steering shaft 4 in the A direction. That is, a pair of outer interposed connecting members 6 and 7 for transmitting rotation in the R direction to the steering shaft 4 and an intermediate interposed connecting member 8 disposed between the pair of outer interposed connecting members 6 and 7 are provided. doing.

  The rotating shaft 2 is a rotating shaft on the electric motor side of the electric power steering apparatus, and the rigid connecting base 3 includes an annular base 11 and an A direction of the base 11 as shown in FIGS. Two pairs of protrusions 13 that protrude integrally from the one annular surface 12 in the A direction toward the connection base 5 and are arranged at equal angular intervals of 90 ° in the R direction, and the rotating shaft 2. 1 and 3, the rigid connecting base 5 has an annular base portion 16 and one annular portion 16 in the A direction of the base portion 16, as shown in FIGS. The steering shaft 4 and two pairs of protrusions 18 that protrude integrally with the surface 17 toward the connection base 3 in the A direction and are arranged at equal angular intervals of 90 ° in the R direction are fitted. And a through hole 19.

  Each of the protrusions 13 has flat side surfaces 21 and 22 as a pair of rigid rotation transmission surfaces in the R direction, and each of the protrusions 18 is also flat as a pair of rigid rotation transmission surfaces in the R direction. Side surfaces 23 and 24.

  As shown in FIG. 7, the rigid intervening connecting member 6 integrally formed of polyacetal resin, polyamide resin, or the like has an annular base 31 concentrically arranged with the bases 11 and 16, and a cylinder of the base 31. And four pairs of inflexible protrusions 33 that extend in the radial direction from the outer peripheral edge 32 and are provided integrally with the base 31 and spaced apart at equal angular intervals of 45 ° in the R direction. doing.

  Each inflexible protrusion 33 has side surfaces 41 and 42 as a pair of rigid rotation transmission surfaces in the R direction.

  Similar to the intervening connecting member 6 arranged between the two connecting bases 3 and 5, it is formed integrally from polyacetal resin, polyamide resin or the like, and has a rigid interposition between the connecting bases 3 and 5. The connecting member 7 is provided integrally with the base 51 and extends in the radial direction from an annular base 51 concentrically with the base 11 and the base 16 and a cylindrical outer peripheral edge 52 of the base 51. It is composed of four pairs of inflexible protrusions 53 that are spaced apart from each other at equal angular intervals of 45 ° in the direction, and is configured in the same manner as the intervening connecting member 6.

  Each inflexible protrusion 53 has side surfaces 61 and 62 as a pair of rigid rotation transmission surfaces in the R direction.

  The intervening connecting member 6 and the intervening connecting member 7 are formed such that the base 31 and the base 51 are inflexible with the intermediate intervening connecting member 8 sandwiched in the A direction with the intermediate intervening connecting member 8 interposed therebetween in the A direction. Each of the elastic protrusions 33 and each of the inflexible protrusions 53 are concentrically arranged so as to face each other in the A direction.

  An intermediate intervening connecting member 8 having an elastic bending rigidity smaller in the R direction than the intervening connecting members 6 and 7 and elastically bending and deformable in the R direction and disposed between the connecting bases 3 and 5 is provided. In particular, as shown in FIG. 8, an annular base 71 concentric with the bases 31 and 51 and a cylindrical outer peripheral edge 72 of the base 71 extend in the radial direction and are provided integrally with the base 71. And four pairs of elastic flexible bending deformable protrusions 73 spaced apart from each other at equal angular intervals of 45 ° in the R direction, and a pair of outer intervening connecting members 6 and 7 in the A direction. Further, they are arranged so as to be slidably movable in the R direction.

  Each elastic bending-deformable protrusion 73 of the intermediate interposition connecting member 8 has a bending rigidity smaller than the bending rigidity in the R direction of the inflexible protrusions 33 and 53 of the intervening connecting members 6 and 7, in other words, Each of the inflexible protrusions 33 and 53 of the intervening connecting members 6 and 7 has an elastic bending and bending deformability greater than the elastic bending and bending deformability in the R direction. In the A direction, the corresponding inflexible protrusions 33 and 53 of the intervening connecting members 6 and 7 are respectively arranged in contact with the corresponding inflexible protrusions 33 and 53 so as to be slidably movable in the R direction. In addition, the inflexible protrusions 33 and 53 are formed with a width D2 larger than the width D1 in the R direction.

  Each of the elastic bending and bending deformable protrusions 73 has a radially extending slit 75 that is opened at the respective radial distal end surface 74 of the elastic bending and bending deformable protrusion 73. Reference numeral 75 denotes a wedge-shaped slit portion 76 having a width d in the R direction that gradually increases from the base portion 71 toward the distal end surface 74, and is connected to the slit portion 76 and elastically bent and deformable. And a circular slit 77 for bending stress dispersion of the root portion 80 of the portion 73.

  Each elastic bending-deformable protrusion 73 has a side surface 78 that contacts the side surface 22 of the protrusion 13 in the R direction and a side surface 79 that contacts the side surface 23 of the protrusion 18 in the R direction.

  The intervening connecting members 6 and 7 and the intermediate intervening connecting member 8 sandwiched between the intervening connecting members 6 and 7 are composed of the base portions 31 and 51 and the base portion 71 and the inflexible protrusions 33 and 53, respectively. Each of the flexible bending deformable protrusions 73 is arranged concentrically so as to face each other in a slidable manner in the A direction.

  The protrusion 13 of the connection base 3 has an intermediate intervening connection between one inflexible protrusion 33 and 53 of the pair of inflexible protrusions 33 and 53 of the intervening connection members 6 and 7 in the R direction and in the R direction. One of the pair of elastic bending and bending deformable protrusions 73 of the member 8 is disposed between the elastic bending and bending deformable protrusions 73 and extends beyond one end surface in the A direction of the interposition connecting member 7 in the A direction. The front end surface 81 faces the surface 17 of the base portion 16 of the connection base 5 with a gap.

  The protrusion 18 of the connection base 5 has an intermediate intervening connection between the other inflexible protrusions 33 and 53 of the pair of inflexible protrusions 33 and 53 of the intervening connection members 6 and 7 in the R direction and in the R direction. Between the pair of elastic bending / deformable protrusions 73 of the member 8, the other elastic bending / deformable protrusion 73 is disposed between the other elastic bending / deformable protrusions 73 and beyond one end surface of the interposition connecting member 6 in the A direction. The front end surface 85 faces the surface 12 of the base 11 of the connection base 3 with a gap.

  With respect to the intermediate intervening connecting member 8 and the intervening connecting members 6 and 7, the protrusions 13 of the connecting base 3 are respectively inflexible protrusions 33 and 53 of the intervening connecting members 6 and 7 in the R direction. Between the one inflexible protrusions 33 and 53, that is, between every other inflexible protrusions 33 and 53, and between each pair of elastic flexible bending deformable protrusions 73 of the intermediate interposition connecting member 8. Are disposed between the other elastic bending / deformable protrusions 73, that is, between every other elastic bending / deformable protrusion 73, and each of the protrusions 18 of the connecting base 5 is interposed in the R direction. Between each pair of inflexible protrusions 33 and 53 of the members 6 and 7, between the other inflexible protrusions 33 and 53, that is, between the remaining inflexible protrusions 33 and 53 and an intermediate interposition connecting member. The other of the 8 elastically flexible bending deformable protrusions 73 Between the remaining flexible bending deformable protrusions 73, that is, between the remaining elastic flexible bending deformable protrusions 73. When the rotation of the rotating shaft 2 and the steering shaft 4 in the R direction below a certain level is connected Each protrusion 13 of the base body 3 has its side surfaces 21 and 22 in the R direction on the side surfaces 79 and 78 in the R direction of the elastic bending and deformation deformable protrusions 73 of the intermediate interposing connecting member 8 facing in the R direction. While being in contact with each other, they are not in contact with the side surfaces 42 and 41 and 62 and 61 of the inflexible protrusions 33 and 53 of the intervening connection members 6 and 7 facing in the R direction. The portion 18 is in contact with the side surfaces 79 and 78 in the R direction of the elastic bending / deformable protrusions 73 of the intermediate interposing connecting member 8 facing in the R direction at the side surfaces 23 and 24 in the R direction, respectively. On the other hand, in the R direction Therefore, the shaft coupling mechanism 1 is composed of the rotating shaft 2 and the steering wheel, respectively, in contact with the side surfaces 42 and 41 and 62 and 61 of the inflexible protrusions 33 and 53 of the intervening coupling members 6 and 7 facing each other. The relative rotation of the shaft 4 in the R direction below a certain level responds with the resistance in the R direction accompanied by the elastic bending bending deformation of the intervening connecting member 8, while making the intervening connecting members 6 and 7 non-responsive. .

  In the electric power steering apparatus provided with the shaft coupling mechanism 1 that couples the rotating shaft 2 and the steering shaft 4 as the above two rotating shafts, when the steering wheel is manually operated by the driver, the steering shaft 4 Rotated in the R direction, the rotation of the steering shaft 4 in the R direction is transmitted as a reciprocating motion to a drag link or the like via a transmission mechanism such as a gear (not shown) to give a steering force to the steered wheels (wheels). 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 contact of the side surface 22 with the side surfaces 41, 61 and 78 or the side surfaces 42, 62 and 79 after the elastic bending and deformation of the elastic bending / deformable protrusion 73 which reduces the width d of the slit portion 76 by the portion 13 is performed. The rotation of the connection base 3 in the R direction is transmitted to the protrusion 18 of the connection base 5 through the pressing of the inflexible protrusions 33 and 53 in the R direction by the protrusion 13 based on the contact of the side surface 21 of the connection 21. The rotational force in the R direction of the rotating shaft 2 is added to the rotational force in the R direction of the steering shaft 4 to assist the driver to manually operate the steering wheel. Thus, when the rotation shaft 2 and the steering shaft 4 are rotated relative to each other in the R direction at a certain level or more, the shaft coupling mechanism 1 is based on the bending bending deformation of the elastic bending-deformable protrusion 73 of the intervening coupling member 8. Resistance in the R direction based on the resistance in the direction and the inflexibility, which is less than the flexibility in bending and deformability of the intervening connecting member 8 in the inflexible protrusions 33 and 53 of the intervening connecting members 6 and 7. In response, the rotation of the rotating shaft 2 in the R direction is transmitted to the steering shaft 4 via the interposing connecting members 6 and 7.

  In the shaft coupling mechanism 1, either the state where the steering wheel is not manually operated by the driver and the steering shaft 4 is not rotated in the R direction or the state where the steering wheel is manually operated by the driver and the steering shaft 4 is rotated in the R direction. Even in this state, in the case where the relative rotation in the R direction of the rotating shaft 2 with respect to the steering shaft 4 is minute within about half of the difference between the width D2 and the width D1, that is, in the case of relative rotation below a certain level. As a result of the elastic bending / deformable protrusion 73 being easily elastically bent and deformed so as to reduce the width d of the slit portion 76, the relative rotation in the R direction of the rotating shaft 2 is hardly applied to the steering shaft 4. Not transmitted, therefore, the impact of the electric motor when reversing through the shaft coupling mechanism 1 and the steering shaft 4 and the transmission of brush vibration to the steering wheel In addition to being able to reduce the steering feeling and making the steering feeling uncomfortable, the elastic bending-deformable protrusion 73 whose width d of the slit portion 76 is zero is after a certain amount of elastic bending bending deformation, that is, a certain relative rotation or more. After that, contact of the side surface 22 with the side surfaces 41 and 61 or contact of the side surface 21 with the side surfaces 42 and 62 occurs, and as a result, further elastic bending and bending deformation of the elastic bending and bending deformable protrusion 73 can be suppressed. It is possible to prevent mechanical fatigue related to the elastic bending bending deformation of the respective base portions 80 of the deformable protrusions 73, and the protrusions 13 and 18 and the elastic bending bends in the relative rotation of the rotating shaft 2 and the steering shaft 4 in a certain R direction. The side surfaces 21 and 22 and 23 and 24 and the side surfaces 78 and 79 in the R direction with the deformable protrusion 73 can be kept in contact with each other over a long period of time. Play of the R direction so that hardly generated between. The intervening connecting members 6 and 7 are configured such that the steering shaft 4 is rotated in the R direction by manual operation by the driver of the steering wheel, and the rotating shaft 2 is rotated in the R direction by the operation of the electric motor. When the rotary shaft 2 is relatively rotated in the R direction to a certain level or more, that is, about half or more of the difference between the width D2 and the width D1, the contact of the side surface 22 with the side surface 78 accompanied by the contact with the side surfaces 41 and 61 Alternatively, by pressing the inflexible protrusions 33 and 53 in the R direction by the protrusion 13 based on the contact of the side surface 21 with the side surface 79 with the contact with the side surfaces 42 and 62, the relative rotation in the R direction is more than a certain level. In response, the rotation of the rotating shaft 2 in the R direction is transmitted to the steering shaft 4 to assist the rotation of the steering shaft 4.

  In addition, a pair of intervening connecting members against a relative rotation within a half of the difference between the width D2 and the width D1, which is a relative rotation of the rotation shaft 2 and the steering shaft 4 in the R direction, which are less than a certain amount in the R direction. The intervening connecting member 6 which is the other intervening connecting member of the pair of intervening connecting members responds with resistance in the R direction accompanied by elastic bending and bending deformation of the intervening connecting member 8 which is one of the intervening connecting members. Alternatively, in this example, both the intervening connecting members 6 and 7 are made unresponsive, and the difference between the width D2 and the width D1, which is a relative rotation of the rotating shaft 2 and the steering shaft 4 in the R direction, which is more than a certain relative rotation. Is less than the resistance in the R direction based on the bending and deformation in the R direction of the intervening connecting member 8 and the elastic bending and deformability of the intervening connecting member 8. Intervening connecting member 6 and According to the shaft coupling mechanism 1 adapted to transmit the rotation of the rotary shaft 2 to the steering shaft 4 via the intervening coupling members 6 and 7 in response to the resistance in the R direction based on the inflexibility of the Since the transmission of the rotation of the rotating shaft 2 in the R direction to the steering shaft 4 is performed via the elastic deformation of the elastic bending and bending deformable protrusion 73 of the intermediate interposing connecting member 8, the rotation shaft 2 has a minute amount in the R direction. Transmission of the rotation to the steering shaft 4 can be reduced or prevented by the elastic bending and bending deformation of the elastic bending and bending deformable protrusion 73 of the intermediate interposition connecting member 8, and the relative rotation of the rotating shaft 2 in the R direction with respect to the steering shaft 4 is large. Can be directly transmitted to the steering shaft 4 via the intervening connecting members 6 and 7 having an elastic bending and bending deformability smaller than the elastic bending and bending deformable protrusion 73 of the intermediate intervening connecting member 8. In the relative rotation of the rotating shaft 2 with respect to the steering shaft 4 in the R direction more than a certain level, the intermediate coupling member 8 and the intermediate coupling member 8 having a large rigidity have a large rigidity. Since the deformation can be prevented, mechanical fatigue related to the elastic bending bending deformation of each of the elastic bending bending deformable protrusions 73, particularly the root portion 80, can be prevented.

  The shaft coupling mechanism 1 in the above example is composed of one intermediate intervening coupling member 8, but may instead be composed of two or more intermediate intervening coupling members 8. And each of 7 may also consist of two or more. Further, the protrusions 13 and 18 of the connection bases 3 and 5, the inflexible protrusions 33 and 53 of the intermediate connection members 6 and 7, and the elastic bending / deformable protrusion 73 of the intermediate connection member 8 are as described above. It is not limited.

  Further, as shown in FIG. 10, the protrusions of the connection bases 3 and 5 so that a gap 101 is formed between the inner peripheral surface 100 and the outer peripheral edge 72 of the protrusions 13 and 18 of the connection bases 3 and 5. It is also possible to reduce the length in the radial direction of 13 and 18 or reduce the diameter of the outer peripheral edge 72 of the base 71 so that the elastic bending and bending deformation of the elastic bending and bending deformable protrusion 73 can be reliably performed.

DESCRIPTION OF SYMBOLS 1 Shaft coupling mechanism 2 Rotating shaft 3, 5 Connecting base 4 Steering shaft 6, 7, 8 Intervening connecting member

Claims (11)

  A shaft coupling mechanism that couples two rotary shafts via a pair of intervening coupling members that are arranged between the two rotary shafts and transmit the rotation of one rotary shaft to the other rotary shaft. Responds to a relative rotation of the shaft around its axis with a resistance in the direction around the axis accompanied by an elastic bending bending deformation of one of the pair of intervening connecting members. On the other hand, the other intervening connecting member of the pair of intervening connecting members is made unresponsive, and one of the intervening connecting members is bent and bent with respect to a relative rotation in a direction around the axis of the two rotating shafts. In the direction around the axis based on the inflexibility based on the resistance in the direction around the axis based on the deformation and the inelasticity bending bending deformability smaller than the elastic bending bending deformability of one of the interposed connecting members of the other interposed connecting member Respond with resistance, the other through Shaft connecting mechanism via the connecting member is adapted to transmit the rotation of one rotating shaft to the other rotating shaft.   One connecting base connected to one rotating shaft and the other connecting base connected to the rotating shaft of the other rotating shaft are provided, and the pair of interposed connecting members are arranged between the two connecting bases. The shaft coupling mechanism according to claim 1.   A shaft coupling mechanism for an electric power steering apparatus, wherein one rotating shaft is coupled to one of an output rotating shaft of an electric motor and a steering shaft of an automobile, and the other rotating shaft is The shaft coupling mechanism according to claim 1, wherein the shaft coupling mechanism is coupled to the other one of the steering shaft of the automobile and the output rotation shaft of the electric motor.   One intervening connecting member includes a first base and at least a pair of elastic flexure bending deformable protrusions provided integrally and radially projecting from the first base. The intervening connecting member is provided with a second base portion and a radially projecting integral with the second base portion, and has a bending bending smaller than the pair of elastic bending-deformable protrusions of one intervening connecting member. The shaft coupling mechanism according to any one of claims 1 to 3, further comprising at least a pair of inflexible protrusions having deformability. 5. The shaft coupling mechanism according to claim 4, wherein each of the elastic flexible bending deformable protrusions has a width in a direction around an axis that is larger than a width in a direction around the axis of the inflexible protrusion.
Mounted shaft coupling mechanism.   An axis coupling mechanism that is arranged between two rotary shafts to connect the two rotary shafts so as to transmit the rotation of one rotary shaft to the other rotary shaft, and includes a pair of outer intervening coupling members, An intermediate interposition connection member disposed between the pair of outer interposition connection members, one connection base connected to one rotation shaft, and the other connection base connected to the other rotation shaft. Each of the pair of outer intervening connecting members has at least a pair of inflexible protrusions that are spaced apart from each other in the direction around the axis and extend in the radial direction. A pair of elastic members disposed between the pair of inflexible protrusions of the pair of outer intervening connecting members in the axial direction and having a width larger than the width in the direction around the axis of each pair of the inflexible protrusions It has a flexible bending deformable protrusion, and one and the other Each of the base bodies includes a base and a protrusion integrally protruding in the axial direction from one surface of the base in the axial direction. The protrusions of the one connecting base are a pair in the direction around the axis. Between one pair of inflexible protrusions of each pair of inflexible protrusions on the outer side of the intermediate connection member and between a pair of elastically flexible bending deformable protrusions of the intermediate intermediate connection member in the direction around the axis. Between the pair of inflexible protrusions of the pair of outer intervening connecting members in the direction around the axis. A shaft connection disposed between the other inflexible projections and the other elastic flexure bendable projections of the pair of elastic flexure bendable projections of the intermediate interposition connecting member in the direction around the axis. mechanism. An axis coupling mechanism that is arranged between two rotary shafts to connect the two rotary shafts so as to transmit the rotation of one rotary shaft to the other rotary shaft, and includes a pair of outer intervening coupling members, An intermediate interposition connection member disposed between the pair of outer interposition connection members, one connection base connected to one rotation shaft, and the other connection base connected to the other rotation shaft. Each of the pair of outer intervening connecting members has at least a pair of elastically flexible bending deformable protrusions spaced apart from each other in the direction around the axis and extending in the radial direction. The connecting member is disposed between the pair of elastically flexible bending deformable protrusions of the pair of outer intervening connecting members in the axial direction and has a width in the direction around the axis of each pair of the elastic bending and bending deformable protrusions. A pair of inflexible protrusions with a small width The one and the other connecting bases each include a base and a protrusion integrally protruding in the axial direction from one surface of the base in the axial direction. Is one elastic bending-deformable projecting protrusion between each pair of elastic bending-deformable projecting protrusions of the pair of outer intervening coupling members in the direction around the axis and an intermediate intervening connection in the direction around the axis One of the inflexible protrusions between the pair of inflexible protrusions of the member is arranged, and the protrusion of the other connecting base is a pair of intervening connecting members on the outer side in the direction around the axis. The other inflexible protrusions between the pair of inflexible protrusions of the intermediate interposition connecting member in the direction between the other elastic bending bendable protrusions and the direction around the shaft center. A shaft coupling mechanism arranged between them.   The shaft coupling mechanism according to any one of claims 4 to 7, wherein each of the pair of elastic bending and bending deformable protrusions has a slit extending in a radial direction.   The shaft coupling mechanism according to claim 8, wherein the slit is opened at a distal end surface in a radial direction of each of the pair of elastic bending and bending deformable protrusions.   The shaft coupling mechanism according to claim 8, wherein the slit is closed at a distal end portion in the radial direction of each of the pair of elastic bending and bending deformable protrusions.   11. The slit has a width in a direction around an axis that gradually increases from the root portion of the elastic bending / deformable protrusion to the tip surface of the elastic bending / deformable protrusion. The shaft coupling mechanism according to any one of the above.

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