JP5719132B2 - In-wheel motor drive device - Google Patents

Description

  The present invention relates to an in-wheel motor drive device in which an output shaft of an electric motor and a wheel hub are connected via a speed reducer.

A conventional in-wheel motor drive device 101 is described in, for example, Japanese Patent Laid-Open No. 2009-216190 (Patent Document 1).
As shown in FIG. 15, the in-wheel motor drive device 101 includes a motor unit 103 that generates a driving force inside a housing 102 that is attached to a vehicle body, a wheel hub bearing unit 104 that is connected to a wheel, and a motor unit 103. And a speed reduction portion 105 that reduces the rotation and transmits the reduced speed to the wheel hub bearing portion 104.

  In the in-wheel motor drive device 101 having the above configuration, a low torque and high rotation motor is employed for the motor unit 103 from the viewpoint of making the device compact. On the other hand, the wheel hub bearing portion 104 requires a large torque to drive the wheel. For this reason, a cycloid reducer that is compact and provides a high reduction ratio is often used for the reduction unit 105.

  The speed reduction unit 105 to which the cycloid reduction gear is applied includes a motor side rotation member 106 having eccentric portions 106a and 106b, curved plates 107a and 107b arranged on the eccentric portions 106a and 106b, and curved plates 107a and 107b. A rolling bearing 106c that is rotatably supported with respect to the member 106; a plurality of outer pins 108 that engage with the outer peripheral surfaces of the curved plates 107a and 107b to cause the curved plates 107a and 107b to rotate; and the curved plates 107a, And a plurality of inner pins 109 for transmitting the rotation motion of 107b to the output shaft 110.

  Incidentally, as shown in FIG. 16, the wheel hub bearing portion 104 includes a hub wheel 111 fixedly connected to the output shaft 110 and an outer portion that rotatably holds the hub wheel 111 with respect to the speed reduction portion housing 102 a of the speed reduction portion 105. And a direction member 112.

  The hub wheel 111 has a cylindrical portion 113 and a flange 114. Driving wheels are fixedly connected to the flange 114 by bolts 115.

  A step portion 116 is provided on the outer peripheral surface of the end portion on the speed reduction portion 105 side of the cylindrical portion 113, and an inner ring 117 is fitted to the step portion 116. A first inner raceway surface 118 is provided in the vicinity of the flange on the outer peripheral surface of the cylindrical portion 113 of the hub wheel 111, and a second inner raceway surface 119 is provided on the outer peripheral surface of the inner ring 117.

  The outer member 112 is provided with two rows of outer raceway surfaces 120 and 121 on its inner periphery, and a flange 132 that is fixed to the speed reduction unit housing 102a of the speed reduction unit 105 with a bolt 133 on its outer periphery. . The first outer raceway surface 120 of the outer member 112 and the first inner raceway surface 118 of the hub wheel 111 face each other, and the second outer raceway surface 121 of the outer member 112 and the second inner raceway surface of the inner ring 117 are opposed. 119 faces each other, and a rolling element 122 is interposed between them.

  The shaft portion 123 of the output shaft 110 of the speed reduction portion 105 is inserted into the tube portion 113 of the hub wheel 111. The shaft portion 123 has a screw portion 124 formed at the end opposite to the speed reduction portion 105, and a spline portion 125 is formed between the screw portion 124 and the speed reduction portion 105. Further, a spline portion 126 is formed on the inner peripheral surface (inner diameter surface) of the tube portion 113 of the hub wheel 111, and when the shaft portion 123 is inserted into the tube portion 113 of the hub wheel 111, The spline portion 125 engages with the spline portion 126 on the hub wheel 111 side.

  Then, the nut member 127 is screwed onto the screw portion 124 of the shaft portion 123 protruding from the tube portion 113, and the hub wheel 111 and the output shaft 110 of the speed reduction portion 105 are connected. At this time, the inner end surface (back surface) 128 of the nut member 127 and the outer end surface 129 of the cylindrical portion 113 are in contact with each other, and the end surface 130 of the output shaft 110 of the speed reduction unit 105 and the outer end surface 131 of the inner ring 117 are in contact with each other. That is, by tightening the nut member 127, the hub wheel 111 is sandwiched between the nut member 127 and the output shaft 110 of the speed reduction unit 105 via the inner ring 117.

  As described above, the speed reduction unit 105 and the wheel hub bearing unit 104 in the conventional in-wheel motor drive device 101 are connected by the engagement between the spline unit 125 on the shaft unit 123 side and the spline unit 126 on the hub wheel 111 side. Is.

JP 2009-216190 A

  For this reason, it is necessary to perform spline processing on both the shaft portion 123 side and the hub wheel 111 side of the speed reduction portion 105, which increases the cost and at the time of press-fitting, the spline portion 125 on the shaft portion 123 side and the hub wheel 111 side. It is necessary to match the unevenness with the spline part 126. At this time, if the tooth surface is aligned and press-fitted, the uneven tooth may be damaged (peeled). Moreover, if it press-fits by matching the large diameter of an uneven | corrugated tooth | gear, without matching a tooth surface, the play of a circumferential direction will arise easily. As described above, when there is a backlash in the circumferential direction, the transmission performance of the rotational torque is inferior and abnormal noise may occur. For this reason, it has been difficult to establish both the damage to the concavo-convex teeth and the play in the circumferential direction in the case of spline fitting as in the prior art.

  Further, it is necessary to screw the nut member 127 to the screw portion 124 of the shaft portion 123 protruding from the cylindrical portion 113. For this reason, there is a problem that it has a screw fastening operation at the time of assembly, is inferior in workability, has a large number of parts, and inferior in part manageability.

  In addition, when a cycloid reducer is applied to the speed reducing unit 105, although a compact and high reduction ratio can be obtained, a plurality of pins must be provided, and conventionally, these pins have been bolted one by one. Also in the mechanism of the part, the assemblability is inferior, and there are problems of an increase in the number of parts and parts manageability.

  In particular, the inner pin 109 receives a load corresponding to the transmission torque from the curved plates 107a and 107b. Since this load is supported by a part of the inner pins 109 that are in contact with the curved plates 107a and 107b, breakage of the inner pins 109 is also a problem.

  Since the in-wheel motor drive device 101 does not require a large-scale power transmission mechanism such as a propeller shaft or a differential, it is attached under the spring of the vehicle on the other hand, which is attracting attention from the aspect of weight reduction and compactness of the vehicle. In particular, if the unsprung weight is not reduced, there is a problem that the ride comfort is deteriorated, and a further reduction in weight is desired.

Accordingly, the present invention is an in-wheel motor that is light in weight by reducing the number of parts, and that is excellent in connection workability between the hub wheel and the output shaft of the speed reduction unit, and that prevents backlash and abnormal noise in the connection unit. It is an object of the present invention to provide a driving device.
It is another object of the present invention to provide an in-wheel motor drive device that employs a cycloid reducer that can appropriately support a load generated by the rotation of a curved plate. Furthermore, it is an object of the present invention to provide an in-wheel motor drive device that is excellent in reduction of the number of components, component management, and assembly workability as the entire in-wheel motor drive device.

  In order to solve the above-described problems, the present invention provides a motor unit that generates a driving force inside a housing that is attached to a vehicle body, a wheel hub bearing unit that is connected to a wheel, and a wheel that decelerates rotation of the motor unit. In an in-wheel motor drive device including a speed reduction portion that transmits to a hub bearing portion, the wheel hub bearing portion is configured as follows.

  That is, the wheel hub bearing portion in the in-wheel motor drive device of the present invention has an outer member having a plurality of outer raceways on the inner periphery and a hub wheel attached to the wheel, and on the tube portion of the hub wheel. A hub wheel comprising an inner member having a plurality of inner raceways facing the outer raceway of the outer member, and a plurality of rows of rolling elements disposed between the outer raceway and the inner raceway facing each other. A convex portion extending in the axial direction is provided on one of the inner diameter surface of the cylinder portion and the outer diameter surface of the shaft portion of the output shaft of the speed reduction portion fitted into the cylinder portion of the hub wheel, and the output shaft of the speed reduction portion By pressing one of the shaft part and the cylindrical part of the hub wheel into the other along the axial direction, a concave part scraped off by the convex part is formed on the other, and the concave part and the convex part are fitted to each other. The concave-convex fitting structure which adheres in the whole area of the part is configured.

  It is desirable to form a gap between the tooth bottom portion between the convex portions adjacent in the circumferential direction and the protruding portion formed on the other side and facing the tooth bottom portion in the radial direction.

  In the indentation fitting structure of the wheel hub bearing portion in the in-wheel motor drive device of the present invention, since the convex portion and the concave portion are in close contact with each other in the entire fitting contact portion, there is a backlash in the radial direction and the circumferential direction. No gap is formed.

  Of the outer diameter surface of the shaft portion of the output shaft of the speed reduction portion and the inner diameter surface of the cylindrical portion of the hub wheel, when a convex portion formed on one side is press-fitted into the other along the axial direction, the convex portion is formed on the counterpart concave surface. The shape of the part is transferred. At this time, the convex portion bites into the concave-part forming surface on the other side, so that the shaft hole is slightly expanded in diameter, allowing the convex portion to move in the axial direction and stopping the axial movement. In this case, the diameter of the shaft hole is reduced to return to the original diameter. As a result, the convex portion and the concave portion are brought into close contact with the entire fitting contact portion.

  When the convex part of the concave-convex fitting structure is provided on the shaft part of the output shaft of the speed reducing part, the hardness of at least the axial end part of the convex part is made higher than the inner diameter surface of the cylindrical part of the hub wheel. By increasing the hardness of the convex portion, the fitting property at the time of the press-fitting is improved, the adhesion is improved, and the assembling workability and the fitting accuracy can be improved.

  Further, it is preferable that a pocket portion for accommodating a protruding portion generated by forming the concave portion by the press-fitting is provided on the shaft portion of the output shaft of the speed reducing portion. Here, the protruding portion is the material of the capacity of the concave portion into which the concave portion fitting portion of the convex portion is fitted (fitted), and is extruded from the formed concave portion, or cut to form the concave portion. It is comprised from what was extruded, what was extruded, and what was cut. You may provide the collar part which aligns between a shaft part and a hub ring in the axial part of a shaft end side rather than a pocket part. The inner diameter dimension of the cylindrical portion of the hub wheel is smaller than the diameter dimension of the circle connecting the maximum diameter portions of the plurality of convex portions provided on the shaft portion of the output shaft of the speed reduction portion, and the circle connecting the minimum diameter portions between the convex portions. Larger than the diameter dimension of.

  When the convex portion of the concave-convex fitting structure is provided on the inner diameter surface of the cylindrical portion of the hub wheel, the hardness of at least the axial end portion of the convex portion is made higher than the outer diameter portion of the shaft portion of the output shaft of the speed reduction portion. .

  In this case, it is preferable that a pocket portion for accommodating the protruding portion generated by the press-fitting is provided on the inner diameter surface of the hub wheel. The outer diameter dimension of the shaft part of the output shaft of the speed reduction part is larger than the diameter dimension of the circle connecting the minimum diameter parts of the plurality of convex parts provided on the cylindrical part of the hub wheel, and the circle connecting the maximum diameter parts between the convex parts. Is smaller than the diameter dimension.

  In the projecting direction intermediate portion of the convex portion, it is desirable that the circumferential dimension of the convex portion is smaller than the groove width between the convex portions adjacent in the circumferential direction. In addition, it is desirable that the sum of the circumferential dimensions of the protrusions is smaller than the sum of the groove widths between the protrusions adjacent to each other in the circumferential direction at an intermediate portion in the protrusion direction of the protrusions.

  The inward member can be constituted by the hub ring having one inner raceway surface and the inner ring that is fitted on the hub ring and has the other inner raceway surface.

  A cycloid reducer with a high reduction ratio can be used as the reduction unit. Then, by connecting the inner pin of the cycloid reducer and the flange portion of the output shaft with the concave-convex fitting structure, the flange portion and the inner pin are brought into close contact with each other at the fitting contact portion. A pin can receive a load, and without increasing the number of parts, variation in the load acting between the curved plate and the inner pin can be suppressed, and the load per inner pin can be reduced.

  The fitting structure of the wheel hub bearing portion adopted by the in-wheel motor drive device of the present invention does not form a gap in which the backlash occurs in the radial direction and the circumferential direction, so that all of the fitting parts contribute to rotational torque transmission, Stable torque transmission is possible, and no abnormal noise is generated. Furthermore, since the contact is made without a gap, the strength of the torque transmitting portion is improved. For this reason, even if the length in the axial direction of the fitting portion is made shorter than that of a spline fitting with the same diameter, the torque transmission force does not decrease, and the in-wheel motor drive device is made lightweight and compact. be able to.

  A convex portion provided on one of the outer diameter surface of the shaft portion of the speed reduction portion and the inner diameter surface of the cylindrical portion of the hub wheel is press-fitted into the other along the axial direction, thereby closely fitting the convex portion. A recess can be formed. For this reason, an uneven | corrugated fitting structure can be formed reliably. Moreover, since it is not necessary to form spline parts etc. on the member where the recesses are formed, it is excellent in productivity and does not require phase alignment between the splines. The tooth surface can be prevented from being damaged, and a stable fitting state can be maintained.

  If the convex part of the concave-convex fitting structure is provided on the shaft part of the output shaft of the reduction part, and the hardness of the axial end part of the convex part is higher than the inner diameter part of the hole part of the hub wheel, the shaft part side The hardness of the shaft portion can be increased, and the rigidity of the shaft portion can be improved.

  Further, a convex portion of the concave-convex fitting structure is provided on the inner diameter surface of the cylindrical portion of the hub wheel, and the hardness of the axial end portion of the convex portion is made higher than the outer diameter portion of the shaft portion of the output shaft of the speed reduction portion. For example, since it is not necessary to perform the hardness treatment (heat treatment) on the shaft portion side, the output shaft of the speed reduction portion is excellent in productivity.

  By providing a pocket portion for storing the protruding portion generated by forming the concave portion by the press-fitting, the protruding portion can be held (maintained) in the pocket, and the protruding portion may enter the vehicle outside the apparatus. Absent. That is, the protruding portion can be kept stored in the pocket portion, and it is not necessary to perform the removal processing of the protruding portion, the number of assembling work can be reduced, and the assembling workability can be improved and the cost can be reduced. Can be planned.

  In addition, by providing a collar portion that performs alignment between the shaft portion and the hub wheel on the shaft end side of the shaft portion relative to the pocket portion, there is no protrusion of the protruding portion in the pocket portion to the collar portion side, Storage of the protruding portion becomes more stable. In addition, since the collar portion is used for alignment, the shaft portion can be press-fitted into the hub wheel while preventing misalignment. For this reason, the output shaft of the speed reduction unit and the hub wheel can be coupled with high accuracy, and stable torque transmission is possible.

  In addition, by arranging the intermediate part in the protruding direction of the convex part on the concave part forming surface before forming the concave part, the convex part bites into the concave part forming surface during press-fitting, so that the concave part can be reliably formed. it can.

  Further, the speed reduction portion is a cycloid reduction gear having a high reduction ratio, and a convex portion extending in the axial direction is provided along either the flange portion of the output shaft or the inner pin of the cycloid reduction gear. Then, by press-fitting one into the other, on the other side, a concave portion scraped off by the convex portion is formed, and when the concave-convex fitting structure in which the concave portion and the convex portion are in close contact with each other in the entire fitting contact portion, The load acting on the inner pin can be received by all the inner pins via the flange part, and the variation in the load acting between the curved plate and the inner pin is suppressed without increasing the number of parts, and the load per inner pin is reduced. The load can be reduced and the durability can be improved. Thereby, as a whole in-wheel motor drive device, it is lightweight and compact, and assembly workability | operativity can be improved.

  By making the circumferential dimension of the convex portion smaller than the groove width between the convex portions adjacent to each other in the circumferential direction, the protruding portion on the side where the concave portion is formed (the concave portion is formed). On the side, the circumferential dimension of the intermediate portion in the protruding direction of the protruding portion generated between the recesses can be increased. For this reason, the shear area of the protruding portion can be increased, and the torsional strength can be ensured. Moreover, since the tooth thickness of the convex portion on the higher hardness side is small, the press-fitting load can be reduced and the press-fitting property can be improved.

It is a schematic sectional drawing of the in-wheel motor drive device concerning one Embodiment of this invention. It is an enlarged view of the motor part of FIG. It is an enlarged view of the deceleration part of FIG. It is an enlarged view of the wheel hub bearing part of FIG. It is an enlarged view which shows the state before fixing the hub ring of FIG. 1 to the output shaft of a deceleration part. The uneven | corrugated fitting structure of a wheel hub bearing part is shown, (a) is an expanded sectional view, (b) is the X section enlarged view of (a). It is a principal part expanded sectional view which shows the modification of an uneven | corrugated fitting structure. It is an enlarged view of other embodiment of a wheel hub bearing part. (A) is the elements on larger scale which show an example of the uneven | corrugated fitting structure of a wheel hub bearing part, (b) is the elements on larger scale which show an example of the uneven | corrugated fitting structure of an inner pin. The uneven | corrugated fitting structure of other embodiment of a wheel hub bearing part is shown, (a) is an expanded sectional view, (b) is the Y section enlarged view of (a). It is sectional drawing of the XI-XI line of FIG. It is a schematic plan view of the electric vehicle which has the in-wheel motor drive device of FIG. It is the figure seen from the electric vehicle back of FIG. It is an enlarged view of other embodiment of a wheel hub bearing part. It is a schematic sectional drawing of the conventional in-wheel motor drive device. It is an enlarged view of the fixing | fixed part of the output shaft of a deceleration part and a wheel hub bearing part in the conventional in-wheel motor drive device.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
As shown in FIG. 12, an electric vehicle 11 including an in-wheel motor drive device according to an embodiment of the present invention includes a chassis 12, a front wheel 13 as a steering wheel, a rear wheel 14 as a drive wheel, And an in-wheel motor drive device 21 that transmits a driving force to each of the rear wheels 14. As shown in FIG. 13, the rear wheel 14 is accommodated in a wheel housing 12a of the chassis 12, and is fixed to the lower portion of the chassis 12 via a suspension device (suspension) 12b.

  The suspension device 12b supports the rear wheel 14 by a suspension arm extending to the left and right, and suppresses vibration of the chassis 12 by absorbing vibration received by the rear wheel 14 from the ground by a strut including a coil spring and a shock absorber. Furthermore, a stabilizer that suppresses the inclination of the vehicle body when turning is provided at the connecting portion of the left and right suspension arms. The suspension device 12b is an independent suspension type in which the left and right wheels can be moved up and down independently in order to improve the followability to the road surface unevenness and efficiently transmit the driving force of the driving wheels to the road surface. Is desirable.

  The electric vehicle 11 needs to be provided with a motor, a drive shaft, a differential gear mechanism, and the like on the chassis 12 by providing an in-wheel motor drive device 21 for driving the left and right rear wheels 14 inside the wheel housing 12a. This eliminates the need to secure a wide cabin space and control the rotation of the left and right drive wheels.

  On the other hand, in order to improve the running stability of the electric vehicle 11, it is necessary to suppress the unsprung weight. Further, in order to secure a wider cabin space, the in-wheel motor drive device 21 is required to be smaller and lighter.

  As shown in FIG. 1, the in-wheel motor drive device 21 includes a motor unit A that generates a driving force, a deceleration unit B that decelerates and outputs the rotation of the motor unit A, and an output from the deceleration unit B as driving wheels. (Rear wheel) 14 is provided with a wheel hub bearing portion C to be transmitted, and the motor portion A and the speed reduction portion B are accommodated in the motor portion housing 22a and the speed reduction portion housing 22b, and as shown in FIG. It is mounted in the wheel housing 12a.

  As shown in FIG. 4, the wheel hub bearing portion C includes an inner member composed of a hub ring 32 and an inner ring 36 that fits into a stepped portion 35 provided on the speed reduction portion B side of the cylindrical portion 34 of the hub ring 32. And an outer member 33 fitted on the cylindrical portion 34 of the hub wheel 32.

  The outer member 33 is provided with two rows of outer raceways (outer races) 37, 38 on the inner circumference thereof, and a first inner raceway (inner race) provided on the outer circumference of the shaft portion of the first outer raceway surface 37 and the hub wheel 32. Race) 39, the second outer raceway surface 38 and the second inner raceway surface (inner race) 40 provided on the outer peripheral surface of the inner ring 36 are opposed, and a ball as the rolling element 73 is interposed between them. Intervened. A seal member S is attached to both openings of the outer member 33.

  The hub wheel 32 includes a cylindrical portion 34 and a flange 42 provided at the end of the cylindrical portion 34 on the side opposite to the deceleration portion B. The hole part of the cylinder part 34 is provided with a shaft part fitting hole 34a at the intermediate part in the axial direction, a tapered hole 34b on the anti-decelerating part B side, and a large-diameter hole 34c on the speed reducing part B side. That is, the shaft portion 28b of the output shaft 28 of the speed reduction portion B and the hub wheel 32 are coupled to each other in the shaft portion fitting hole 34a via the concave-convex fitting structure M described later.

In this case, the end surface of the inner ring 36 of the hub wheel 32 on the side of the speed reduction part B is pressed against the flange part 28a of the output shaft 28 of the speed reduction part B, preload is applied to the wheel hub bearing part C, and the inner ring 36 is moved to the hub wheel. 32 is fixed. A bolt mounting hole 43 is provided in the flange 42 of the hub wheel 32, and a hub bolt 74 for fixing the wheel and the brake rotor to the flange 42 is mounted in the bolt mounting hole 43.
As shown in FIG. 14, the inner ring 36 may apply a preload to the bearing by crimping the end of the hub ring 32. Reference numeral 34 d indicates a caulking portion at the end of the hub wheel 32.

  As shown in FIG. 6, the concave-convex fitting structure M includes, for example, a convex portion 45 provided at an end portion of the shaft portion 28b and extending in the axial direction, and an inner diameter surface of the hole portion of the hub wheel 32 (in this case, the shaft portion). The concave portion 46 is formed in the inner diameter surface 48) of the fitting hole 34 a, and the entire concave portion fitting portion 47 of the convex portion 45 is in close contact with the corresponding concave portion 46. That is, a plurality of convex portions 45 are arranged at a predetermined pitch along the circumferential direction on the outer peripheral surface of the shaft portion 28b on the side opposite to the deceleration portion B, and the inner diameter surface of the shaft portion fitting hole 34a of the hole portion of the hub wheel 32. A plurality of concave portions 46 into which the convex portions 45 are fitted to 48 are formed along the circumferential direction. That is, the convex part 45 and the concave part 46 fitted to this are tight-fitted over the entire circumference in the circumferential direction.

  In this case, each convex portion 45 has a triangular shape (mountain shape) having a convex rounded apex in cross section, and the concave portion fitting portion 47 of each convex portion 45 is a range A shown in FIG. It is the range from the middle part of the mountain shape to the mountaintop in the cross section. Further, a gap 49 is formed between the adjacent convex portions 45 in the circumferential direction on the inner diameter side than the inner diameter surface 48 of the hub wheel 32. In other words, the gap 49 is provided between the tooth bottom portion between the convex portions 45 and the protruding portion provided in the hole portion of the hub wheel 32 and facing the tooth bottom portion in the radial direction.

  In this way, the hub wheel 32 and the output shaft 28 of the speed reduction part B can be connected via the concave / convex fitting structure M. At this time, the end surface of the inner ring 36 of the hub wheel 32 on the speed reduction part B side is pressed by the flange part 28a of the output shaft 28 to apply preload to the wheel hub bearing part C.

  In the present invention, the concave / convex fitting structure M is in close contact with the corresponding concave portion 46 of the concave portion 47 of the convex portion 45. There is no gap in which play occurs in the direction. For this reason, all the fitting parts contribute to rotational torque transmission, stable torque transmission is possible, and no abnormal noise is generated.

  Next, the fitting method of the uneven fitting structure M will be described. In this case, as shown in FIG. 5, a spline 50 is formed on the outer diameter portion of the shaft portion 28 b of the output shaft 28 of the speed reduction portion B, and a heat curing process is performed, so that the spline 50 is formed in the cured layer H. . For this reason, the peak part of the spline 50 is hardened, and this peak part becomes the convex part 45 of the concave-convex fitting structure M. The inner surface of the cylindrical portion 34 of the hub wheel 32 is an uncured portion that is not subjected to thermosetting. In FIG. 5, the cross hatched portion indicates the hardened layer H. The hardness difference between the hardened layer H and the uncured portion of the inner diameter surface of the cylindrical portion 34 of the hub wheel 32 is 30 points or more in HRC. The module of the spline 50 of the shaft portion 28b is a small tooth of 0.5 or less. Here, the module is a pitch circle diameter divided by the number of teeth.

At this time, the intermediate portion in the protruding direction of the convex portion 45 is made to correspond to the position of the concave portion forming surface (in this case, the inner diameter surface 48 of the shaft portion fitting hole 34a) of the hub wheel 32. The inner diameter dimension D of the inner diameter surface 48 of the shaft section fitting hole 34a has a diameter dimension (circumscribed circle diameter) of a circle connecting the maximum diameter portion of the convex portion 45 smaller than D _1, a circle connecting outermost diameter portion between the convex portion It is set to be larger than the diameter D _2. That is, D ₂ <D <D ₁ is satisfied.

  The spline 50 can be formed by various processing methods such as rolling, cutting, pressing, drawing, etc., which are conventional publicly known means. Moreover, various heat processing, such as induction hardening and carburizing hardening, can be employ | adopted as a thermosetting process.

Then, as shown in FIG. 5, the shaft portion 28 b of the output shaft 28 is inserted into the hub wheel 32 in a state where the shaft center of the hub wheel 32 and the shaft center of the output shaft 28 of the speed reduction portion B are aligned ( Press fit). In this case, the diameter D of the inner diameter surface 48 of the tubular portion 34, the maximum outer diameter dimension D ₁ of the convex portion 45, a minimum outer diameter dimension D ₂ and the like of the relationship of the recesses of the spline 50, moreover Since the hardness of the convex portion 45 is 30 points or more larger than the hardness of the inner diameter surface of the cylindrical portion 34, if the shaft portion 28b is press-fitted into the cylindrical portion 34 of the hub wheel 32, the convex portion 45 bites into the inner diameter surface. Thus, the concave portion 46 into which the convex portion 45 is fitted is formed along the axial direction.

  As a result, as shown in FIG. 6, it is possible to configure a fitting state in which the entire fitting portion of the convex portion 45 and the concave portion 46 at the end of the shaft portion 28 b is in close contact. That is, the shape of the convex portion 45 is transferred to the other-side concave portion forming surface (in this case, the inner diameter surface 48 of the shaft portion fitting hole 34a of the cylindrical portion 34). At this time, as the convex portion 45 bites into the inner diameter surface 48 of the cylindrical portion 34, the cylindrical portion 34 is slightly expanded in diameter, allowing the convex portion 45 to move in the axial direction, and the axial direction. If the movement stops, the diameter of the cylindrical portion 34 is reduced to return to the original diameter. In other words, when the convex portion 45 is press-fitted, the cylindrical portion 34 of the hub wheel 32 is elastically deformed in the radial direction, and a preload corresponding to this elastic deformation is applied to the tooth surface of the convex portion 45 (the surface of the concave portion fitting portion 47). . For this reason, the concave / convex fitting structure M in which the entire concave portion fitting portion 47 of the convex portion 45 is in close contact with the corresponding concave portion 46 can be reliably formed. In addition, the member (in this case, the hub wheel 32) in which the concave portion 46 is formed does not need to be formed with a spline portion, etc., is excellent in productivity, and does not require phase alignment between the splines. In addition, it is possible to avoid damage to the tooth surface during press-fitting and maintain a stable fitting state.

  As in the above-described embodiment, the spline 50 formed on the shaft portion 28b uses small teeth with a module of 0.5 or less, so that the formability of the spline 50 can be improved and the press-fit load can be reduced. Can be achieved. In addition, since the convex part 45 can be comprised with the spline normally formed in this kind of shaft, this convex part 45 can be easily formed at low cost.

  Further, when the concave portion 46 is formed by press-fitting the shaft portion 28b into the hub wheel 32, work hardening occurs on the concave portion 46 side. Here, work hardening means that when plastic deformation (plastic processing) is applied to an object, resistance to deformation increases as the degree of deformation increases, and the material becomes harder than a material that has not undergone deformation. For this reason, the plastic deformation at the time of press-fitting hardens the inner diameter surface 48 of the hub wheel 32 on the recess 46 side, thereby improving the rotational torque transmission.

Incidentally, in the spline 50 shown in FIG. 5, the pitch of the convex portions 45 of the shaft portion 28b and the pitch of the concave portions 46 of the hub wheel 32 are set to be the same. For this reason, in the embodiment, as shown in FIG. 6, at the intermediate portion in the protruding direction of the convex portion 45, the circumferential dimension L of the convex portion 45 and the groove width L ₀ between the convex portions 45 adjacent in the circumferential direction are Are almost the same.

On the other hand, as shown in FIG. 7, the circumferential dimension L < _b > ₂ of the convex portion 45 is smaller than the groove width L < _b > ₁ between the convex portions 45 adjacent in the circumferential direction at the intermediate portion in the protruding direction of the convex portion 45. It may be a thing. That is, in the spline 50 formed on the shaft portion 28b, the projecting direction intermediate portion of the convex portion 45 circumferential dimension (the tooth thickness) L _2, the hub wheel 32 side to be fitted between the protrusions 45 of the protrusion 51 It is smaller than the circumferential dimension of the projecting direction intermediate portion (tooth thickness) L _1.

In addition, at the intermediate portion in the protruding direction of the convex portion 45, the total tooth thickness Σ (B ₁ + B ₂ + B ₃ +. It is desirable to set it to be smaller than the total tooth thickness Σ (A ₁ + A ₂ + A ₃ +...) Of 51 (convex teeth). Thereby, the shear area of the protruding portion 51 on the hub wheel 32 side can be increased, and the torsional strength can be ensured. And since the tooth thickness of the convex part 45 is small, a press-fit load can be made small and a press-fit property can be aimed at. The sum of the dimension in the circumferential direction of the convex portion 45, to less than the sum of the circumferential dimension of the projecting portion 51 of the mating, the circumferential dimension L ₂ of all of the projections 45, projecting circumferentially adjacent portion 45 there is no need to be smaller than the groove width L ₁ between. That is, among the plurality of convex portions 45, be the same as the groove width L ₁ between the convex portions circumferential dimension L ₂ of any of the projections 45 are circumferentially adjacent, larger than the groove width L ₁ However, it is sufficient if the sum is small. 7 has a trapezoidal cross section (Mt. Fuji shape).

  By the way, if the shaft part 28b of the speed reduction part B is press-fitted into the hub wheel 32, the material protrudes from the concave part 46 formed by the convex part 45, as shown in FIGS. 8 and 9 of the second embodiment. A protruding portion 52 is formed. The protruding portion 52 is a material component of the capacity of the concave portion 46 into which the concave portion fitting portion of the convex portion 45 is inserted (fitted), and is extruded from the formed concave portion 46, and is cut to form the concave portion 46. Or both extruded and cut. At that time, a gap may be inevitably generated in the concave portion forming process by the convex portion in a very partial region of the fitting portion.

  For this reason, in the wheel hub bearing portion C shown in FIG. 1, after the output shaft 28 of the speed reduction portion B is assembled to the hub wheel 32, it is necessary to remove the protruding portion 52. Therefore, in another embodiment shown in FIG. 8, a pocket portion 53 for accommodating the protruding portion 52 is provided in the shaft portion 28b.

  That is, the pocket portion 53 is formed by providing the circumferential groove 54 at the shaft end edge of the spline 50 of the shaft portion 28b. As shown in FIG. 9A, in the circumferential groove 54, the side wall 55a on the spline 50 side is a plane orthogonal to the axial direction, and the side surface 55b on the anti-spline side extends from the groove bottom 54c to the anti-spline. It is a taper surface which expands toward the side.

  Further, a disc-shaped flange portion 56 for alignment is provided on the side opposite to the spline (shaft end side) from the side surface 55b. The outer diameter dimension of the flange part 56 is set to be the same as the hole diameter of the shaft part fitting hole 34a of the cylindrical part 34 or slightly smaller than the hole diameter of the fitting hole. In this case, a minute gap t is provided between the outer diameter surface 56 a of the flange portion 56 and the inner diameter surface 48 of the shaft portion fitting hole 34 a of the cylindrical portion 34.

  Even in the wheel hub bearing portion C shown in FIG. 8, if the shaft portion 28b is press-fitted into the shaft portion fitting hole 34a of the cylindrical portion 34 of the hub wheel 32, the convex portion 45 on the shaft portion 28b side A recess 46 can be formed on the hub wheel 32 side. At this time, the formed protruding portion 52 is housed in the pocket portion 53 while curling as shown in FIG. That is, a part of the material scraped off or pushed out from the inner diameter surface of the shaft portion fitting hole 34 a of the cylindrical portion 34 enters the pocket portion 53.

  In this way, by providing the pocket portion 53 that accommodates the protruding portion 52 generated by forming the concave portion by the press-fitting, the protruding portion 52 can be held (maintained) in the pocket portion 53, and the protruding portion 52 is outside the apparatus. Never get into any other vehicle. That is, the protruding portion 52 can be kept stored in the pocket portion 53, and it is not necessary to perform the removal processing of the protruding portion 52, the number of assembling operations can be reduced, and the assembling workability can be improved. Cost reduction can be achieved.

  Further, by providing a flange 56 for alignment with the shaft fitting hole 34a of the tube portion 34 of the hub ring 32 on the axially opposite spline side (shaft end side) of the pocket portion 53, the inside of the pocket portion 53 is provided. The protruding portion 52 does not protrude to the flange portion 56 side, and the protruding portion 52 is more stably stored. Moreover, since the collar portion 56 is for alignment, the shaft portion 28b can be press-fitted into the hub wheel 32 while preventing misalignment. For this reason, the output shaft 28 of the deceleration part B and the hub wheel 32 can be connected with high precision, and stable torque transmission becomes possible.

  Since the flange portion 56 is used for alignment during press-fitting, the outer diameter dimension is preferably set to be slightly smaller than the diameter of the shaft portion fitting hole 34a of the cylindrical portion 34 of the hub wheel 32. That is, if the outer diameter dimension of the flange portion 56 is larger than the hole diameter of the fitting hole, the flange portion 56 itself is press-fitted into the shaft portion fitting hole 34a. At this time, if the center is misaligned, the convex portion 45 of the concave-convex fitting structure M is pressed in as it is, and the shaft portion 28b and the hub wheel are not aligned with the shaft center of the shaft portion 28b and the shaft center of the hub wheel 32. 32 will be connected. Moreover, if the outer diameter dimension of the collar part 56 is too smaller than the hole diameter of the shaft part fitting hole 34a, it will not function for alignment. For this reason, it is preferable that the minute gap t between the outer diameter surface 56a of the flange portion 56 and the inner diameter surface 48 of the shaft portion fitting hole 34a of the cylindrical portion 34 is set to about 0.01 mm to 0.2 mm. .

  In the wheel bearing device shown in FIG. 8, the output shaft 28 is press-fitted until the end surface of the inner ring 36 on the speed reduction portion B side is pressed against the flange portion 28a of the output shaft 28. It is preferable that the flange portion 56 does not protrude from the fitting hole 34a. If the flange portion 56 does not protrude from the shaft portion fitting hole 34a, the protruding portion 52 will not protrude from the pocket portion 53, and the spline 50 will not penetrate the shaft portion fitting hole 34a. The combined structure is difficult to move in the axial direction.

  By the way, in each of the above-described embodiments, the spline 50 constituting the convex portion 45 is formed on the shaft portion 28b side, and the spline 50 of the shaft portion 28b is hardened so that the inner diameter surface 48 of the hub wheel 32 is not formed. Hardened (raw material). On the other hand, as shown in FIG. 10, the spline 61 (consisting of the ridges 61a and the ridges 61b) in which the inner diameter surface of the shaft portion fitting hole 34a of the cylindrical portion 34 of the hub wheel 32 is cured. In addition, the shaft portion 28b may not be subjected to a curing process. The spline 61 can also be formed by various processing methods such as broaching, cutting, pressing, and drawing, which are publicly known means. Further, various heat treatments such as induction hardening and carburizing and quenching can be employed as the thermosetting treatment.

In this case, the intermediate portion in the protruding direction of the convex portion 45 is made to correspond to the position of the concave portion forming surface (the outer diameter surface of the shaft portion 28b) before forming the concave portion. In other words, diameter of a circle connecting outermost diameter portion of the convex portion 45 of the splines 61 of the D ₄ (minimum diameter dimension of the convex portion 45), smaller than the outer diameter D ₃ of the shaft portion 28b, the maximum diameter of the spline 61 It is set to be larger than the outer diameter D ₃ of the D ₅ (inner diameter of the fitting hole inner surface between the convex portion) of the shaft portion 28b diameter of a circle connecting. That is, D ₄ <D ₃ <D ₅ .

  When the shaft portion 28b is press-fitted into the shaft portion fitting hole 34a of the cylindrical portion 34 of the hub wheel 32, the concave portion 46 in which the convex portion 45 is fitted to the outer peripheral surface of the shaft portion 28b by the convex portion 45 on the hub wheel 32 side. Can be formed. Thereby, the convex part 45 by the side of the hub wheel 32 and the concave part 46 by the side of the axial part 28b can be closely_contact | adhered in the whole fitting contact site | part.

  Here, the recessed part fitting part of the convex part 45 is the range B shown in FIG.10 (b), and is the range from the mountain-shaped middle part to the summit in the cross section. In addition, a gap 62 is formed between the adjacent convex portions 45 in the circumferential direction on the outer diameter side of the outer peripheral surface of the shaft portion 28b. That is, the gap 62 is provided between the tooth bottom portion between the convex portions 45 and the protruding portion provided in the shaft portion 28b and facing the tooth bottom portion in the radial direction.

  Even in this case, since the protruding portion 52 is formed by press-fitting, it is preferable to provide a pocket portion 53 for storing the protruding portion 52. Unlike the one shown in FIG. 8, the protruding portion 52 is formed on the speed reducing portion B side of the shaft portion 28b, so that the pocket portion is provided on the hub wheel 32 side.

  The present invention is not limited to the above embodiment, and various modifications are possible. For example, as the shape of the convex portion 45 of the concave-convex fitting structure M, the embodiment shown in FIG. Yes, in the embodiment shown in FIG. 7, it is a trapezoidal cross section (Mt. Fuji shape), but other shapes such as a semicircular shape, a semi-elliptical shape, a rectangular shape, etc. can be adopted. The circumferential arrangement pitch and the like can be arbitrarily changed. That is, it is not necessary to form the splines 50 and 61, and the crests of the splines 50 and 61 to be the convex portions 45 of the concave-convex fitting structure M. It is also possible to form a mating surface. In short, the convex portion 45 arranged along the axial direction can be press-fitted into the mating side, and the concave portion 46 can be formed on the mating side with the convex portion 45 so that the convex portion 45 can be closely fitted. It is only necessary that the entire recessed portion fitting portion of the portion 45 is in close contact with the corresponding recessed portion 46, and that rotational torque can be transmitted between the hub wheel 32 and the output shaft 28 of the speed reducing portion B.

  Further, the shaft hole of the hub wheel 32 may be a deformed hole such as a polygonal hole other than a circular hole, and the cross-sectional shape of the end portion of the shaft portion 28b fitted into the shaft hole is also a polygon other than a circular cross section. It may be an irregular cross section. For this reason, for example, the shaft hole of the hub wheel 32 can be a circular hole, the cross-sectional shape of the shaft part 28b can be a polygon other than a circle, and the edge part can be the convex part 45.

  In the embodiment, the convex portion 45 is subjected to thermosetting treatment, and the convex portion corresponding side is set as an uncured portion, and the hardness of the convex portion 45 is higher than the portion where the concave portion 46 is formed. If possible, both may be heat treated or both may not be heat treated. Furthermore, since only the press-fitting start end portion of the convex portion 45 is required to have a higher hardness than the portion where the concave portion 46 is formed, it is not necessary to increase the overall hardness of the convex portion 45. In FIG. 6 and the like, the gap 49 is formed. However, the gap 49 between the convex portions 45 may bite into the inner diameter surface of the hub wheel 32. In addition, as described above, the hardness difference between the convex portion 45 side and the concave portion forming surface formed by the convex portion 45 is preferably 30 points or more by HRC, but the convex portion 45 is press-fitted. If possible, it may be less than 30 points.

  In the above-described embodiment, the end surface (press-fit start end) of the convex portion 45 is desirably a surface orthogonal to the axial direction, whereby a good adhesion structure with shaving can be obtained. However, it may be inclined at a predetermined angle with respect to the axial direction. In this case, it may be inclined from the inner diameter side toward the outer diameter side toward the anti-convex portion side or inclined toward the convex portion side.

  Further, as the shape of the pocket portion 53, in the above-described embodiment, the circumferential groove 54 has a side surface 55b on the anti-spline side that is a tapered surface that expands from the groove bottom 54c toward the anti-spline side. In other words, it is sufficient that the protruding portion 52 to be generated can be accommodated (accommodated), and therefore, the capacity of the pocket portion 53 can correspond to the generated protruding portion 52. That's fine.

As shown in FIG. 2, the motor unit A includes a stator 23 fixed to the motor unit housing 22 a, a rotor 24 disposed at a position facing the inner side of the stator 23 with a radial gap therebetween, A radial gap motor including a motor-side rotation member 25 that is fixedly connected to the inside and rotates integrally with the rotor 24.
The motor-side rotating member 25 has a hollow shape and is rotatably supported with respect to the motor unit housing 22a by rolling bearings 72a and 72b.

  An input shaft 26 is arranged in the hollow portion of the motor side rotation member 25 from the motor portion A to the speed reduction portion B in order to transmit the driving force of the motor portion A to the speed reduction portion B.

  The input shaft 26 in the speed reduction portion B has eccentric portions 26 a and 26 b and rotates integrally with the rotor 24. Further, the two eccentric portions 26a and 26b are provided with a 180 ° phase change so as to cancel out the centrifugal force caused by the eccentric motion.

  As shown in FIG. 3, the speed reduction part B is held at curved positions 27a and 27b as revolving members that are rotatably held by the eccentric parts 26a and 26b, and fixed positions on the speed reduction part housing 22b. A plurality of outer pins 29 as outer peripheral engagement members that engage with the outer peripheral portion of 27b, adjacent to the eccentric portions 26a and 26b, the motion conversion mechanism for transmitting the rotational motion of the curved plates 27a and 27b to the output shaft 28, and the eccentric portions 26a and 26b. A counterweight 30 is provided at the position. In addition, the speed reduction part B is provided with a speed reduction part lubrication mechanism that supplies lubricating oil to the speed reduction part B.

  The output shaft 28 has a flange portion 28a and a shaft portion 28b. Holes 31a for fixing the inner pins 31 at equal intervals on the circumference centering on the rotation axis of the output shaft 28 are formed in the end face of the flange portion 28a. The shaft portion 28 b is fitted and fixed to the hub wheel 32, and transmits the output of the speed reduction portion B to the wheel (rear wheel) 14. A flange portion 28a of the output shaft 28 rotatably supports the input shaft 26 by a rolling bearing 36c.

  As shown in FIG. 11, the curved plate 27 a (27 b) has a plurality of corrugations composed of trochoidal curves such as epitrochoids on the outer peripheral portion, and a plurality of through holes penetrating from one end face to the other end face 30a (30b). A plurality of through holes 30a (30b) are provided at equal intervals on the circumference centering on the rotation axis of the curved plate 27a (27b), and receive an inner pin 31 described later. Further, the through hole 30c is provided at the center of the curved plate 27a (27b) and is fitted to the eccentric portion 26a (26b).

  The curved plate 27a (27b) is rotatably supported with respect to the eccentric part 26a (26b) by a rolling bearing 41a (41b). The rolling bearing 41a (41b) is fitted to the outer diameter surface of the eccentric portion 26a (26b), and has an inner ring member having an inner raceway surface on the outer diameter surface, and inner diameter surfaces of the through holes 30c of the curved plates 27a and 27b. A retainer (not shown) that holds an interval between an outer raceway surface formed directly on the inner raceway, a plurality of cylindrical rollers 44a (44b) disposed between the inner raceway surface and the outer raceway surface, and an adjacent cylindrical roller 44a (44b). (Omitted).

  The outer pins 29 are provided at equal intervals on a circumferential track centering on the rotation axis of the input shaft 26. When the curved plate 27a (27b) revolves, the curved waveform and the outer pin 29 are engaged to cause the curved plates 27a and 27b to rotate. Here, the outer pin 29 has a needle roller bearing at a position in contact with the outer peripheral surface of the curved plate 27a (27b). Thereby, the contact resistance between the curved plate 27a (27b) can be reduced.

  The counterweight 30 has a disc shape and has a through-hole that fits with the input shaft 26 at a position off the center. Each counterweight 30 is offset in order to counteract the unbalanced inertia couple caused by the rotation of the curved plates 27a and 27b. It is arranged at a position adjacent to the portions 26a and 26b with a 180 ° phase change from the eccentric portion.

  The motion conversion mechanism includes a plurality of inner pins 31 held by the output shaft 28 and through holes 30a and 30b provided in the curved plates 27a and 27b. The inner pins 31 are provided at equal intervals on a circumferential track centering on the rotational axis of the output shaft 28, and one axial end thereof is fixed to the output shaft 28. Further, in order to reduce the frictional resistance with the curved plates 27a and 27b, needle roller bearings are provided at positions where they contact the inner wall surfaces of the through holes 30a and 30b of the curved plates 27a and 27b.

  As described above, the concave / convex fitting structure M employed for connecting the output shaft 28 of the speed reduction portion B and the hub wheel 32 has a small number of parts and maintains the shaft member and the shaft hole in a stable fitting state. Therefore, the concave-convex fitting structure M is formed by fixing the outer pin 29 of the speed reduction portion B, the inner pin 31 and the flange portion 28a of the output shaft 28, and the hub ring 32 and the shaft portion 28b of the output shaft 28. By adopting not only the fitting structure but also the mounting structure of the outer pin 29 of the speed reducer B, the weight can be reduced and the assemblability can be improved.

  When the concave-convex fitting structure M is used for fixing the inner pin 31 and the hole 31a of the output shaft 28, one of the convex portions extending in the axial direction provided in either one is press-fitted in the other along the axial direction. By doing so, a concave portion scraped off by the convex portion is formed on the other side, this concave portion is formed, and the concave portion and the convex portion are in close contact with each other in the entire fitting contact portion.

  As shown in FIG. 9B, the concave-convex fitting structure M employed for fixing the inner pin 31 and the hole portion 31a of the output shaft 28 has an inner pin at the end of the hole portion 31a on the wheel hub bearing portion C side. This is basically the same as the above-described coupling between the shaft portion 28b of the output shaft 28 and the shaft portion fitting hole 34a of the cylindrical portion 34 of the hub wheel 32, except that the locking portion 81 with which the tip surface of 31 abuts is formed. Therefore, parts having the same configuration are denoted by the same reference numerals, and detailed description thereof is omitted.

  The concave-convex fitting structure M of the inner pin 31 is equidistantly arranged in the circumferential direction between the convex portion 45 provided at the end of the inner pin 31 on the wheel hub bearing portion C side and extending in the axial direction, and the flange portion 28a of the output shaft 28. And the concave portion 46 formed on the inner diameter surface of the hole portion 31 a is provided in the hole portion 31 a, and the entire concave portion fitting portion of the convex portion 45 is in close contact with the corresponding concave portion 46. That is, a plurality of convex portions 45 provided on the inner pin 31 are arranged at a predetermined pitch along the circumferential direction, and a plurality of convex portions 45 are fitted into the inner diameter surface of the hole portion 31a of the flange portion 28a of the output shaft 28. A recess 46 is formed along the circumferential direction. That is, the convex part 45 and the concave part 46 fitted to this are tight-fitted over the entire circumference in the circumferential direction.

  A disc-shaped flange 56 for alignment is provided at the end of the inner pin 31 on the wheel hub bearing portion C side. The outer diameter of the flange 56 is set to be the same as the hole diameter of the hole 31a or slightly smaller than the hole diameter of the hole 31a. In this case, a minute gap t is provided between the outer diameter surface 56a of the flange portion 56 of the inner pin 31 and the inner diameter surface of the hole portion 31a of the flange portion 28a.

  Further, a locking portion 81 is provided in the hole portion 31 a of the flange portion 28 a, and the inner pin 31 is moved until the wheel hub bearing C side surface 55 b of the flange portion 56 of the inner pin 31 hits the locking portion 81. By press-fitting, a plurality of inner pins 31 are positioned in the circumferential direction so as not to come out with respect to the wheel hub bearing portion C side.

  Since the convex portion 45 of the inner pin 31 does not penetrate the hole portion 31a of the flange portion 28a due to the contact between the locking portion 81 and the flange portion 56, the protruding portion 52 causes the concave-convex fitting structure to form the motor portion. It also becomes difficult to move to the A side.

  Further, since the flange portion 56a is aligned with the flange portion 28a by the flange portion 56a, the flange portions 56 of the plurality of inner pins 31 are previously fitted into the fitting holes, If press-fitting at a time in the state, the assemblability is improved. Thus, even if it press-fits at once, since there is the collar part 56, it can engage | insert perpendicularly with respect to the flange part 28a.

  The through holes 30a, 30b provided in the curved plates 27a, 27b are provided at positions corresponding to the respective inner pins 31, and the inner diameter of the through holes 30a, 30b is the outer diameter of the inner pin 31 (“needle-like” The maximum outer diameter including the roller bearing ". The same shall apply hereinafter).

  The speed reduction unit lubrication mechanism supplies lubricating oil to the speed reduction unit B, and includes a lubricating oil supply port 22c, a lubricating oil discharge port 22d, a lubricating oil storage unit 22e, a lubricating oil passage 22f, and a rotary pump 71. And a circulating oil passage 22g.

  The circulating oil passage 22g extends along the axial direction inside the input shaft 26. The lubricating oil supply port 22c is provided in the eccentric portions 26a and 26b.

Hereinafter, the operation principle of the in-wheel motor drive device 21 will be described.
The motor unit A receives, for example, an electromagnetic force generated by supplying an alternating current to the coil of the stator 23, and the rotor 24 composed of a permanent magnet or a magnetic material rotates. As a result, when the motor-side rotating member 25 connected to the rotor 24 rotates, the curved plates 27 a and 27 b revolve around the rotation axis of the motor-side rotating member 25. At this time, the outer pin 29 engages with the curved waveform of the curved plates 27 a and 27 b to cause the curved plates 27 a and 27 b to rotate in the direction opposite to the rotation of the motor-side rotating member 25.

  The inner pins 31 inserted through the through holes 30a and 30b come into contact with the inner wall surfaces of the through holes 30a and 30b as the curved plates 27a and 27b rotate. As a result, the revolving motion of the curved plates 27a and 27b is not transmitted to the inner pin 31, but only the rotational motion of the curved plates 27a and 27b is transmitted to the wheel hub bearing portion C via the output shaft 28 of the speed reduction portion B.

  At this time, since the rotation of the motor-side rotating member 25 is decelerated by the deceleration unit B and transmitted to the output shaft 28, even when the low-torque, high-rotation type motor unit A is employed, the drive wheels (rear wheels) 14 It is possible to transmit the torque required for.

  Note that the reduction ratio of the speed reduction portion B having the above-described configuration is calculated as (ZA−ZB) / ZB, where ZA is the number of outer pins 29 and ZB is the number of waveforms of the curved plates 27a and 27b. In the embodiment shown in FIG. 11, since ZA = 12, ZB = 11, the reduction ratio is 1/11, and a very large reduction ratio can be obtained.

  In this way, by adopting the speed reduction unit B that can obtain a large speed reduction ratio without using a multi-stage configuration, the in-wheel motor drive device 21 having a compact and high speed reduction ratio can be obtained. Further, since the needle roller bearings are provided on the outer pin 29 and the inner pin 31, the frictional resistance between the curved plates 27a and 27b is reduced, so that the transmission efficiency of the speed reducing portion B is improved.

  By employing the in-wheel motor drive device 21 according to the above embodiment in the electric vehicle 11, the unsprung weight can be suppressed. As a result, the electric vehicle 11 having excellent running stability can be obtained.

  In the above embodiment, an example of a cylindrical roller bearing is shown as a bearing for supporting the curved plates 27a and 27b. However, the present invention is not limited to this, and for example, a plain bearing, a cylindrical roller bearing, a tapered roller bearing, and a needle roller Regardless of whether it is a plain bearing or a rolling bearing, such as a bearing, a self-aligning roller bearing, a deep groove ball bearing, an angular contact ball bearing, or a four-point contact ball bearing, whether the rolling element is a roller or a ball Furthermore, any bearing can be applied regardless of whether it is a double row or a single row. Similarly, any type of bearing can be adopted for bearings arranged in other locations.

  However, the deep groove ball bearing has a higher allowable limit speed than the cylindrical roller bearing, but has a low load capacity. Therefore, in order to obtain a necessary load capacity, a large deep groove ball bearing must be employed. Therefore, from the viewpoint of making the in-wheel motor drive device 21 compact, a cylindrical roller bearing is suitable for the rolling bearing 41.

  In each of the above-described embodiments, an example in which a radial gap motor is adopted as the motor unit A has been described. However, the present invention is not limited to this, and a motor having an arbitrary configuration can be applied. For example, it may be an axial gap motor including a stator fixed to the casing and a rotor disposed at a position facing the inner side of the stator with an axial gap.

  Moreover, in each said embodiment, although the example of the in-wheel motor drive device 21 which employ | adopted the cycloid deceleration mechanism as the deceleration part B was shown, it is not restricted to this, Arbitrary deceleration mechanisms can be employ | adopted. For example, a planetary gear reduction mechanism, a parallel shaft gear reduction mechanism, or the like is applicable.

  Furthermore, although the electric vehicle 11 shown in FIG. 10 has shown the example which used the rear wheel 14 as the driving wheel, it is not restricted to this, The front wheel 13 may be used as a driving wheel and may be a four-wheel drive vehicle. . In the present specification, “electric vehicle” is a concept including all vehicles that obtain driving force from electric power, and should be understood as including, for example, a hybrid vehicle.

  As mentioned above, although embodiment of this invention was described with reference to drawings, this invention is not limited to the thing of embodiment shown in figure. Various modifications and variations can be made to the illustrated embodiment within the same range or equivalent range as the present invention.

DESCRIPTION OF SYMBOLS 11 Electric vehicle 12 Chassis 12a Wheel housing 12b Suspension device 13 Front wheel 14 Rear wheel 21 In-wheel motor drive device 22a Motor part housing 22b Deceleration part housing 22c Lubricating oil supply port 22d Lubricating oil discharge port 22e Lubricating oil storage part 22f Lubricating oil path 22g Circulating oil path 23 Stator 24 Rotor 25 Motor side rotating member 26 Input shafts 26a and 26b Eccentric portions 27a and 27b Curved plates 30a and 30b Through hole 28 Output shaft 28a Flange portion 28b Shaft portion 29 Outer pin 30 Counterweight 31 Inner pin 32 Hub Ring 33 Outer member 34 Tube portion 34a Shaft portion fitting hole 34b Taper hole 34c Large diameter hole 34d Caulking portion 35 Step portion 36 Inner ring 37 First outer raceway surface (outer race)
38 Second outer raceway (outer race)
39 First inner raceway surface (inner race)
40 Second inner raceway surface (inner race)
41a, 41b Rolling bearing 42 Flange 44a, 44b Cylindrical roller 45 Convex part 46 Concave part 47 Concave fitting part 48 Inner surface 49 Gap 50 Spline 51 Protruding part 52 Protruding part 53 Pocket part 54 Circumferential groove 54c Groove bottom 55a Side wall 55b Side face 56 Threaded portion 56a Outer diameter surface 61 Spline 61a Convex strip 61b Concave strip 62 Clearance 71 Rotating pumps 72a, 72b Rolling bearing 72c Rolling bearing 73 Rolling body 74 Hub bolt 81 Locking portion A Motor portion B Deceleration portion C Wheel hub bearing portion M Concavity and convexity Composite structure H hardened layer

Claims (1)

An in-wheel comprising: a motor unit that generates a driving force inside a housing attached to the vehicle body; a wheel hub bearing unit connected to the wheel; and a reduction unit that decelerates the rotation of the motor unit and transmits the reduced speed to the wheel hub bearing unit. In the motor drive device, the speed reduction unit is a cycloid speed reducer, and is rotatably held by an input shaft having an eccentric portion, an output shaft, and the eccentric portion, and the rotation axis is accompanied by the input shaft. a curved plate to perform revolving motion around an outer pin causing rotation motion on the curved plate engaged with the outer peripheral portion of the curved plates, the rotation axis of the input shaft rotation motion of the curved plates A motion conversion mechanism that converts the rotational motion around the center and transmits the motion to the output shaft. The motion conversion mechanism includes a plurality of through holes that penetrate the curved plate in the thickness direction, and one end portion in the axial direction. the flange portion of the output shaft Parts are held in, and a plurality of inner pins to be inserted into the through hole in a state that at a radial gap between said through-hole, and the hole portion of the flange portion of the output shaft and the inner pin, Protrusions that extend in the axial direction are provided on either side, and one is pressed into the other along the axial direction, thereby forming a recess that is scraped off by the protrusion on the other. configure the recess-projection fitting structure in close contact across the contact portion, in-wheel motor drive device, characterized in that said pin does not penetrate the hole portion of the flange portion of the output shaft.

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