JP6518516B2 - Suspension structure of in-wheel motor drive device - Google Patents

Description

  The present invention relates to a suspension structure of an in-wheel motor drive device, and more particularly to a technology for improving unsprung motion of the suspension structure to improve ride comfort performance of a vehicle.

  Since the in-wheel motor is disposed in the wheel to drive the wheel, there is no need to mount a drive source on the vehicle body as in a conventional vehicle engine, and the internal space of the vehicle body is effectively used. Can. Further, as compared with the conventional vehicle engine, the drive source can be made smaller and lighter.

  Conventionally, as a suspension device for attaching an in-wheel motor to a vehicle body, for example, a device as described in Japanese Patent Application Laid-Open No. 2008-155694 (Patent Document 1) is known. The suspension device of Patent Document 1 is a left and right independent suspension system, and includes one damper, two upper rods, and three lower rods.

Patent Document 1: JP 2008-155694 A Paragraph 0017

  The unsprung movement when the wheel rides on the unevenness or step of the road surface in the above conventional suspension device is shown in FIGS. FIG. 15 is a side view of the state before the wheels get on the step in the vehicle width direction of the vehicle. FIG. 16 is a side view of a state in which the wheels have run up on the step in the vehicle width direction of the vehicle, and a state before the run-up is shown by a virtual line for reference. When a wheel 111 attached to a vehicle body 115 via a suspension device rides on a step 113 or unevenness projecting from a flat road surface 112, a damper of the suspension device (not shown) contracts and each rod of the suspension device (not shown) swings upward. The wheels move upward with the in-wheel motor 114 as indicated by the arrows in FIG. That is, the movement amount of the in-wheel motor and the movement amount of the wheel are naturally equal.

  The inventor has found that there is a point to be improved in the movement of the wheel and in-wheel motor described above, that is, the unsprung movement of the suspension device. That is, since the unsprung weight of the suspension device is large in the drive wheel driven by the in-wheel motor as compared with the drive wheel of a vehicle equipped with a vehicle engine, as shown in FIG. The following problems occur when the amount of movement is equal.

  First, the cornering power of the tire of the wheel changes with the change of the ground contact load, so the difference in tire lateral force between the left and right wheels becomes large, which causes the problem of a decrease in straight-line stability that the vehicle moves laterally. is there. Such problems cause deterioration in the durability of the road wheel of the wheel and an increase in the amount of wear on the tire.

  Second, the unsprung resonance frequency of the suspension device decreases and approaches the resonance frequency of the vehicle body. Therefore, there is a problem that the vibration transmission rate to the vehicle body is increased in the frequency band near the unsprung resonance frequency. Such problems deteriorate the ride quality of the vehicle.

  Although not shown, the same problem occurs because the wheel and the in-wheel motor move in the opposite direction to the above-described movement when moving down the step.

  An object of the present invention is to provide a technique for improving unsprung motion in a suspension device for attaching an in-wheel motor to a vehicle body in view of the above-described situation.

  To this end, the suspension structure according to the first invention comprises an in-wheel motor including a wheel hub bearing portion and a motor portion outputting rotation to the wheel hub bearing portion and having a center of gravity offset from the axis of the wheel hub bearing portion in the vehicle longitudinal direction. A drive unit, a suspension member for mounting the wheel hub bearing on the vehicle body side member so as to be vertically displaceable, a center of gravity movement restricting link which is installed between the in-wheel motor drive unit and the vehicle body side member to restrict vertical movement of the center of gravity Equipped with

  Alternatively, the suspension structure according to the second invention includes an in-wheel motor drive device including a wheel hub bearing portion and a motor portion outputting rotation to the wheel hub bearing portion and having a center of gravity offset from the axis of the wheel hub bearing portion in the vehicle longitudinal direction. A suspension member is mounted between the in-wheel motor drive unit and the suspension member, and a center of gravity movement restricting link is provided between the in-wheel motor drive and the suspension member to restrict the vertical movement of the center of gravity.

  According to the first and second aspects of the invention, since the wheel hub bearing portion and the suspension member are vertically displaced, the wheel coupled to the wheel hub bearing portion can get over the step. On the other hand, the center of gravity of the in-wheel motor drive device is restricted from moving in the vertical direction, and is not displaced in the vertical direction or slightly displaced. Thus, the unsprung motion of the suspension structure is improved. The suspension member is not particularly limited, and may be, for example, a strut type arm, a double wishbone type arm, or a multilink type arm. The member on the vehicle body side refers to a member attached to the vehicle body as viewed from the member to be described, and includes not only the vehicle body but also a vehicle body frame attached to the vehicle body, a bracket attached to the vehicle body frame, and other components attached to the vehicle body .

  As one embodiment of the first invention, the center of gravity movement restriction link extends in the vertical direction, the upper end of the center of gravity movement restriction link is connected to the vehicle body side member, and the lower end of the center of gravity movement restriction link is above the center of gravity of the in-wheel motor drive device Connect with the location of

  As one embodiment of the second invention, the suspension member is an arm extending in the vehicle width direction, and the vehicle width direction inner end of the arm is rotatably connected to the vehicle body side member, and the vehicle width direction outer end of the arm is a wheel Connect with hub bearing. One end of the center-of-gravity movement restricting link is connected to the center of the arm in the vehicle width direction, and the other end of the center-of-gravity movement restricting link is connected to the central portion from the center of gravity to the wheel hub bearing. According to this embodiment, it is possible to make the attitude of the in-wheel motor drive device the same as the attitude of the suspension member that swings in the vertical direction. Therefore, while swinging the wheel hub bearing portion of the in-wheel motor drive in the vertical direction like the free end of the suspension member, the center of gravity of the in-wheel motor drive is not moved in the vertical direction as the base end of the suspension member Can be

  Alternatively, a suspension structure according to a third aspect of the present invention includes an in-wheel motor drive device including a wheel hub bearing portion and a motor portion outputting rotation to the wheel hub bearing portion and having a center of gravity offset from the axis of the wheel hub bearing portion in the vehicle longitudinal direction. The in-wheel motor drive device is provided with a pivot that is pivotable about a straight line parallel to the axis of the wheel hub bearing through its center of gravity.

  According to the third aspect of the invention, since the in-wheel motor drive device rotates about its own center of gravity, the wheel hub bearing offset from the center of gravity in the longitudinal direction of the vehicle is displaced in the vertical direction. The coupled wheels can ride over the step.

  In a preferred embodiment of the first to third inventions, the wheel hub bearing portion is coupled to the front wheel of the vehicle and disposed forward of the center of gravity of the in-wheel motor drive device. According to this embodiment, it is possible to secure a long wheel base between the front wheel and the rear wheel, and the traveling stability of the vehicle is improved.

As one embodiment of the present invention, the in-wheel motor drive further includes a parallel biaxial reduction mechanism. According to this embodiment, since the motor unit is offset from the wheel hub bearing unit, the center of gravity of the in-wheel motor drive can be easily offset from the wheel hub bearing unit. As another embodiment of the present invention, the in-wheel motor drive may include other types of reducers such as a planetary gear set or a cycloid reducer, or the in-wheel motor drive may be output from the motor unit Alternatively, it may be a direct drive system in which the rotational speed is not increased or decreased without being increased or decreased.

  In a normal state where the vehicle carries a usual heavy load and travels on a flat road, the wheel hub bearing may be higher or lower than the center of gravity of the in-wheel motor drive. As a preferred embodiment of the present invention, the center of gravity of the in-wheel motor drive is at the same height as the axis of the wheel hub bearing in a normal state or at a position lower than the axis. According to such an embodiment, when the wheel hub bearing portion bounces upward, it is surely higher than the center of gravity of the in-wheel motor drive device. Therefore, the wheel can easily get over the step.

  Thus, according to the present invention, the unsprung motion of the suspension mechanism is improved, the center of gravity of the in-wheel motor drive does not move, or the center-of-gravity movement of the in-wheel motor drive is slight, and the durability of the road wheel As a result, the wear of the tire is reduced and the ride quality of the vehicle is improved.

FIG. 1 is a side view schematically showing a suspension structure according to an embodiment of the present invention. It is a side view which shows typically the state which the wheel of FIG. 1 got on the level | step difference. It is a whole external view which takes out and shows an in-wheel motor drive device. It is sectional drawing in IV-IV in FIG. It is sectional drawing which shows the components which comprise the gravity center of an in-wheel motor drive device. It is a side view showing the state of the whole vehicle in front of level difference riding. It is a side view showing the state of the whole vehicle after getting on a level difference. FIG. 7 is a side view showing a suspension structure according to another embodiment of the present invention. It is a side view which shows the state which the wheel of FIG. 8 got on the level | step difference. It is a side view showing the state of the suspension structure before step difference riding and after step difference riding in comparison. It is a front view showing the state of the suspension structure before step difference riding and after step difference riding in comparison. FIG. 10 is a side view showing a suspension structure according to still another embodiment of the present invention. It is a side view which shows the state which other embodiment mounted on the level | step difference. It is sectional drawing which shows other embodiment. It is a side view showing typically a wheel and an in-wheel motor connected with the conventional suspension device. It is a side view which shows typically the state which the wheel of FIG. 15 got on the level | step difference.

  Hereinafter, embodiments of the present invention will be described in detail based on the drawings. 1 and 2 are side views schematically showing a suspension structure according to an embodiment of the present invention. FIG. 1 shows a state before running on a step, and FIG. 2 shows a state after running on a step. FIG. 3 is an overall external view showing the in-wheel motor drive device taken out of the same embodiment. 1 to 3 show a state viewed in the vehicle width direction of the vehicle. FIGS. 4 and 5 are cross-sectional views taken along line IV-IV in FIG. 3 and show a state as viewed from above the vehicle. The suspension structure of the present embodiment includes an in-wheel motor drive device 11, a vehicle body 61, a suspension member 21 connecting these, and a center-of-gravity movement restricting link 31.

  First, the in-wheel motor drive device 11 is provided with a motor portion 11A, a reduction portion 11B, and a wheel hub bearing portion 11C as shown in FIGS. The wheel hub bearing portion 11C is a double-row rolling bearing having a hub wheel 12 that is a rotating member and an outer ring 13 that is a non-rotating member that rotatably supports the hub wheel 12. The hub wheel 12 is connected to and drives a wheel 41 disposed on the outer side in the vehicle width direction of the vehicle. The outer ring 13 is fixed to a casing 14 forming an outer shell of the motor portion 11A and the reduction portion 11B.

  The motor unit 11A incorporates a rotor and a stator of a rotating electrical machine in the casing 14, and drives the hub wheel 12 or regenerates electric power by using the rotation of the hub wheel 12. The decelerating unit 11B incorporates a decelerating mechanism in the casing 21 and decelerates the rotation of the motor unit 11A and transmits it to the hub wheel 12. The structure of the reduction mechanism is not particularly limited, such as a planetary gear set or a cycloid reduction gear, but in this embodiment, a parallel biaxial reduction mechanism is adopted as shown in FIG. 4 and the axis A of the motor portion 11A and the wheel hub bearing The axes C of the portions 11C are arranged parallel to one another. The axis C is the wheel center of the wheel 41.

  The reduction unit 11B includes an input gear 15, an intermediate gear 16, and an output gear 17. The input gear 15 is an external gear provided at the tip of the motor rotation shaft 19 of the motor unit 11A, and is coaxially arranged with the axis A. The intermediate gear 16 is an external gear disposed coaxially with an axis B parallel to the axis A, and meshes with the input gear 15. The radius (the number of teeth) of the intermediate gear 16 is larger (more) than that of the input gear 15.

  The output gear 17 is an external gear integrally formed with the intermediate gear 16 and coaxially disposed on the axis B. The radius (the number of teeth) of the output gear 17 is smaller (smaller) than that of the intermediate gear 16. The hub wheel gear 18 is an internal gear formed integrally with the hub wheel 12, coaxially disposed along the axis C, and engaged with the output gear 17. The radius (the number of teeth) of the hub wheel gear 18 is larger (more) than that of the output gear 17. As a result, the output rotation of the motor unit 11A is decelerated by the reduction unit 11B and transmitted to the wheel hub bearing unit 11C.

  The axis A of the motor portion 11A, the axis B of the reduction portion 11B, and the axis C of the wheel hub bearing portion 11C are mutually offset and arranged in parallel, and extend in the vehicle width direction of the vehicle. The motor unit 11A, the reduction unit 11B, and the wheel hub bearing unit 11C are arranged in this order in the vehicle width direction, the motor unit 11A is on the inside in the vehicle width direction, and the wheel hub bearing unit 11C is on the outside in the vehicle width direction. . At least the wheel hub bearing portion 11 </ b> C of the in-wheel motor drive device 11 is disposed in the inner empty area of the wheel 41.

  The remaining parts of the in-wheel motor drive device 11 excluding the wheel hub bearing portion 11C are shown by dots in FIG. These remaining components are arranged offset from the axis C of the wheel hub bearing portion 11C, and the center of gravity G of these remaining components is shown in FIGS. That is, the center of gravity G is the center of gravity of the unit portion including the motor portion 11A, the speed reduction portion 11B, and the casing 14 forming the outer shell thereof. Therefore, the center of gravity of the in-wheel motor drive device 11 is offset from the axis C. As shown in FIG. 5, the axis B is offset to the rear of the vehicle than the axis C (the wheel center of the wheel 41), the center of gravity G is offset to the rear of the vehicle than the axis B, and the axis A is the center of gravity G It is disposed offset to the rear of the vehicle. The distance from the center of gravity G to the axis C is the dimension Dw. Further, a ball joint 23 (see FIG. 4) described later is disposed forward of the axis C in the vehicle. In order to facilitate understanding, in FIGS. 4 and 5, the center of gravity G is attached with a straight line parallel to the axis C and the axis A.

  Next, a suspension structure for mounting the in-wheel motor drive device to the vehicle body will be described.

  The suspension member 21 of the suspension structure is an arm extending in the vehicle width direction, and the inward end in the vehicle width direction is connected to the vehicle body 61 via the pivot shaft 22 and the outward end in the vehicle width direction is via the ball joint 23 It is connected with the outer ring 13 of the in-wheel motor drive device 11. The suspension member 21 can be pivoted up and down with the inward end in the vehicle width direction as a base end and the inward end in the vehicle width direction as a free end. The swing center axis of the suspension member 21 is indicated by an alternate long and short dash line in FIGS. 1, 2 and 4. The swing central axis of the suspension member 21 extends through the pivot shaft 22. Although not shown, a shock absorber may be interposed between the in-wheel motor drive device 11 and the vehicle body 61, and another arm or link may be bridged. The shock absorber is a well-known suspension component and normally holds the suspension member 21 in a predetermined posture as shown in FIG.

  As shown in FIG. 1, the center-of-gravity movement restricting link 31 is installed between the in-wheel motor drive device 11 and the vehicle body 61 and restricts the vertical movement of the center of gravity G. Specifically, the center-of-gravity movement restriction link 31 extends in the vertical direction along a virtual straight line connecting the connecting point 32 formed of a ball joint and the center of gravity G. The upper end of the center-of-gravity movement restricting link 31 is connected to the vehicle body 61 via the connection point 32, and the lower end 33 of the center-of-gravity movement restricting link 31 is connected to the casing 14 of the in-wheel motor drive device 11. The casing 14 forms an outer shell of the motor unit 11A and the speed reduction unit 11B. The lower end 33 of the center-of-gravity movement restricting link 31 may simply be connected to the casing 14 by the motor unit 11A or the speed reduction unit 11B, or may be separated from an imaginary straight line connecting the connecting point 32 and the center of gravity G. However, the lower end 33 is a portion of the casing 14 above the center of gravity G.

  Next, the operation of the suspension structure of the present embodiment will be described.

  FIG. 6 is a schematic side view showing a state in which the vehicle travels on a flat surface in the vehicle width direction, and corresponds to FIG. FIG. 7 is a schematic side view showing, in the vehicle width direction, a state in which the front wheel of the vehicle rides on the step, and corresponds to FIG. The suspension structure of the present embodiment is provided at least on the front wheels (wheels 41) of the vehicle, but may be provided on the rear wheels (wheels 51). The suspension structure holds the wheel center (hub wheel 12 and axis C) of the wheel 41 at a predetermined height as shown in FIGS. 1 and 6 under normal conditions where the wheels 41 and 51 both contact the flat surface 101. .

  When the front wheel 41 rides on the step 102 while the rear wheel 51 is in contact with the flat surface 101, the wheel 41 and the ball joint 23 at the free end move upward, and the suspension member 21 pivots upward. However, the in-wheel motor drive device 11 does not move upward, but pivots about the center of gravity G as shown by the arrow in FIG. The reason is that the suspension member 21 permits the upward movement of the wheel hub bearing portion 11C including the hub wheel 12 while the gravity center movement restricting link 31 restricts the upward movement of the gravity center G.

  As shown in FIG. 2, when the wheel 41 rides on the step 102, the vertical movement amount Mv of the wheel center (hub wheel 12, axis C) of the wheel 41 is equal to the height from the flat surface 101 to the step 102. Further, as shown in FIG. 2, the wheel center (wheel hub bearing portion 11C) of the present embodiment draws a trajectory Ct and moves horizontally. However, since the locus Ct is arc-shaped with the center of gravity G at the center, the horizontal movement amount Mh of the wheel center is slight.

  When the front wheel (wheel 41) and the rear wheel (wheel 51) of the vehicle are in contact with the flat surface 101 as shown in FIG. 6, the vertical distance from the center of gravity G to the center of gravity F of the vehicle body 61 is Vs. Let the height to F be Vb. As shown in FIG. 7, when the front wheel (wheel 41) rides on the step 102 while the rear wheel (wheel 51) of the vehicle is in contact with the flat surface 101, the vertical distance from the center of gravity G to the center of gravity F of the vehicle body 61 remains Vs. It does not change. Further, the height from the flat surface 101 to the center of gravity F remains Vb and does not change.

  According to the present embodiment, the suspension member 21 for attaching the wheel hub bearing portion 11C to the vehicle body 61 so as to be vertically displaceable, the in-wheel motor drive device 11 and the vehicle body 61 are bridged to restrict the vertical movement of the center of gravity G. Since the center-of-gravity movement restriction link 31 is provided, even when the wheel 41 rides on the step 102, the center of gravity G does not move upward as shown in comparison with FIGS. 1 and 2. As a result, the vertical distance Vs from the center of gravity G to the center of gravity F of the vehicle body 61 does not change when crossing over the step 102. Also, the vertical distance Vb from the flat surface 101 to the center of gravity F does not change when crossing over the step 102. Further, the horizontal movement amount Mh of the center of gravity G when moving over is small.

  Therefore, according to the present embodiment, the unsprung motion of the suspension structure is improved, the movement of the center of gravity of the in-wheel motor drive is slight, the durability of the road wheel is improved, and the amount of tire wear is suppressed. The ride is improved.

  Next, another embodiment of the present invention will be described. FIGS. 8 and 9 are schematic side views showing a suspension structure according to another embodiment of the present invention as seen in the vehicle width direction of the vehicle, and FIG. 8 shows that the wheel is in contact with a flat surface and FIG. Represents the state of riding on the step. FIG. 10 is a side view showing the state of the suspension structure before and after riding on a step by comparison, and shows the state as viewed in the vehicle width direction of the vehicle. FIG. 11 is a front view showing the state of the suspension structure in front of and behind the step by comparison, showing a state as viewed in the front and rear direction of the vehicle, but for ease of understanding Does not distinguish between The left half of FIG. 11 corresponds to the left half of FIG. 10, and the right half of FIG. 11 corresponds to the right half of FIG. 10, and the heights L1 to L1 are common horizontal lines to easily understand the height change of parts. Attach L7.

  The same reference numerals as in the above-described embodiment denote the same parts as in the above-described embodiment, and a description thereof will be omitted, and different parts will be described below. In another embodiment, the center-of-gravity movement restricting link 34 is installed between the suspension member 24 and the in-wheel motor drive device 11 in place of the above-described gravity center movement restricting link 31.

  The center-of-gravity movement restricting link 34 extends in the vertical direction, and the upper end thereof is connected to the casing 14 of the in-wheel motor drive device 11 through the ball joint 35. The ball joint 35 is provided in the motor portion 11A (see FIG. 10) on the inner side in the vehicle width direction, and is disposed in the central portion between the wheel center (hub wheel 12, axis C) and the center of gravity G of the wheel 41. The horizontal distance from the wheel center (axis C) of the wheel 41 to the center of gravity G is Dw, and the horizontal distance from the ball joint 35 to the center of gravity G is Dl.

  As shown in FIG. 11, the lower end of the gravity center movement restricting link 34 is connected to the suspension member 24 via the ball joint 36. The ball joint 36 is disposed in the central region of the suspension member 24 extending in the vehicle width direction, and the lever ratio thereof is Aw: Al. The distance Aw is the distance from the base end 25 which is the vehicle width direction inner end of the suspension member 24 to the free end 26 which is the vehicle width direction outer end, and the distance Al is the ball joint from the base end 25 of the suspension member 24 The distance to 36 is said. The lever ratio is determined as follows.

Aw: Al = Dw: Dl ..... Formula (1)
The base end 25 of the suspension member 24 is connected to the vehicle body 61 via the pivot shaft 27. The pivot shaft 27 basically extends in the longitudinal direction of the vehicle as shown in FIG. 10, but inclines so as to be gradually higher toward the front. The free end 26 of the suspension member 24 is connected to the lower end of the knuckle 28 via a pivot shaft or a ball joint. The knuckle 28 has a central hole 29. The outer ring 13 of the wheel hub bearing portion 11C of the in-wheel motor drive device 11 is fitted and fixed to the central hole 29, and the hub wheel 12 penetrates.

  The in-wheel motor drive device 11 and the knuckle 28 are installed in the inner empty area of the road wheel 42 of the wheel 41 (see FIG. 11). The hub wheel 12 of the in-wheel motor drive device 11 is coupled to the road wheel 42 by a bolt or the like. The suspension member 24 is a lower arm disposed below the in-wheel motor drive device 11. Although not illustrated, the knuckle 28 extends upward from the in-wheel motor drive device 11, and the upper end of the knuckle 28 is connected to the vehicle body 61 via an upper arm (not shown).

  The operation of the other embodiments is basically the same as that of the above-described embodiments, so only the differences in functions will be described next.

  In another embodiment, the free end 26 of the suspension member 24 is connected to the wheel hub bearing 11C of the in-wheel motor drive device 11 via the knuckle 28, and the central portion (ball joint 36) of the suspension member 24 is a center of gravity movement restricting link Since the central portion between the axis C and the center of gravity G of the in-wheel motor drive device 11 is connected via 34, the in-wheel motor drive device 11 swings in response to the swing of the suspension member 24.

  That is, as shown in FIG. 11, the change in posture of the suspension member 24 seen in the longitudinal direction of the vehicle corresponds to the change in posture of the in-wheel motor drive device 11 seen in the vehicle width direction as shown in FIG.

  Specifically, the relationship between the height of the free end 26 of the suspension member 24, the height of the ball joint 36 provided at the central portion of the suspension member 24, and the height of the base end 25 of the suspension member 24 is in-wheel motor drive The relationship between the height of the axis C of the device 11, the height of the ball joint 35 provided at the central portion of the in-wheel motor drive device 11, and the height of the center of gravity G related to the in-wheel motor drive device 11. Then, the height of the proximal end 25 corresponding to the fulcrum of the lever and the height of the center of gravity G do not change, and the height of the free end 26 corresponding to the action point of the lever and the height of the axis C largely change. The height of the ball joint 36 and the height of the ball joint 35, which correspond to the middle point of the angle .alpha. For details, refer to the heights L1 to L7 shown in FIG. 10 and FIG. L1 indicates the height of the axis C at the time of upward swing. L2 indicates the height of the ball joint 35 when it is pivoted upward. L3 indicates the height of the center of gravity G at the time of upward swing and downward swing, the height of the ball joint 35 at the time of downward swing, and the height of the axis C at the time of downward swing. L4 indicates the height of the free end 26 when it is swung upward. L5 indicates the height of the ball joint 36 when it is pivoted upward. L6 indicates the height of the ball joint 36 at the time of downward rocking. L7 indicates the height of the free end 26 at the time of downward rocking, and the height of the base end 25 at the time of upward rocking and the downward rocking.

  Next, still another embodiment of the present invention will be described. 12 and 13 are schematic side views showing a suspension structure according to another embodiment of the present invention as seen from the vehicle width direction of the vehicle, and FIG. 12 shows that the wheel is grounded to a flat surface, and FIG. Represents the state of riding on the step. FIG. 14 is a cross-sectional view showing still another embodiment. The same reference numerals as in the above-described embodiment denote the same parts as in the above-described embodiment, and a description thereof will be omitted, and different parts will be described below. In another embodiment, the center of gravity G and the vehicle body 61 are pivotably connected by the pivot 37 instead of the center-of-gravity movement restricting links 31 and 34 described above. Further, the wheel hub bearing portion 11C of the in-wheel motor drive device 11 is connected to the vehicle body 61 via the shock absorber 38.

  The pivot 37 includes an axis Gr extending in the vehicle width direction. Thus, the in-wheel motor drive device 11 is attached to the vehicle body 61 so as to be rotatable about the axis Gr.

  The shock absorber 38 normally has a predetermined total length as shown in FIG. 12 and holds the height of the wheel hub bearing portion 11C.

  When the wheel 41 rides on the step as shown in FIG. 13, the shock absorber 38 is contracted to allow the wheel 41 to move upward together with the wheel hub bearing portion 11C. Thus, the shock absorber 38 allows the in-wheel motor drive device 11 to swing up and down with the wheel 41 with the pivot 37 as a fulcrum.

  Since the operation of the other embodiment is basically the same as that of the above-described embodiment, only the functional difference will be described next.

  According to still another embodiment, as shown in FIG. 14, the in-wheel motor drive device 11 can be rocked by pivoting the pivot 37. At this time, the center of gravity G is at the base end, and the wheel hub bearing portion 11C is at the free end. Further, the shock absorber 38 regulates the careless rocking of the in-wheel motor drive device 11, and stably holds the wheel hub bearing portion 11C at a predetermined height shown in FIG.

  Although the embodiments of the present invention have been described above with reference to the drawings, the present invention is not limited to the illustrated embodiments. Various modifications and variations can be made to the illustrated embodiment within the same or equivalent scope of the present invention.

  The suspension structure according to the present invention is advantageously used in an electric vehicle and a hybrid vehicle provided with an in-wheel motor drive.

11 In-wheel motor drive, 11A motor unit,
11B reducer, 11C wheel hub bearing, 12 hub wheels,
13 outer ring, 14 casing, 15 input gear,
16 intermediate gears, 17 output gears, 18 hub ring gears,
19 motor rotation shaft, 21 suspension member, 22 rotation shaft,
23 ball joints, 24 suspension members,
25 proximal ends, 26 free ends, 28 knuckles, 29 central holes,
31 barycentric movement control link, 32 upper end (connection point), 33 lower end,
34 barycentric movement control link, 35, 36 ball joint,
37 pivot, 38 shock absorbers,
41 wheels (front wheels), 51 wheels (rear wheels), 61 car bodies,
101 flat surface, 102 steps.

Claims (8)

An in-wheel motor drive device including a wheel hub bearing portion and a motor portion outputting rotation to the wheel hub bearing portion, and having a center of gravity offset from the axis of the wheel hub bearing portion in the longitudinal direction of the vehicle;
A suspension member for attaching the wheel hub bearing portion to a vehicle body side member so as to be vertically displaceable;
A suspension structure of an in-wheel motor drive device, comprising: a center-of-gravity movement restricting link which is installed between the in-wheel motor drive device and a vehicle body side member and restricts vertical movement of the center of gravity.   The center of gravity movement restriction link extends in the vertical direction, the upper end of the center of gravity movement restriction link is connected to the vehicle body side member, and the lower end of the center of gravity movement restriction link is connected to a location above the center of gravity in the in-wheel motor drive device The suspension structure of the in-wheel motor drive according to claim 1. An in-wheel motor drive device including a wheel hub bearing portion and a motor portion outputting rotation to the wheel hub bearing portion, and having a center of gravity offset from the axis of the wheel hub bearing portion in the longitudinal direction of the vehicle;
A suspension member for attaching the wheel hub bearing portion to a vehicle body side member so as to be vertically displaceable;
A suspension structure of an in-wheel motor drive device, comprising: a center-of-gravity movement restricting link which is installed between the in-wheel motor drive device and the suspension member to restrict the vertical movement of the center of gravity. The suspension member is an arm extending in the vehicle width direction, the vehicle width direction inner end of the arm is rotatably connected to the vehicle body side member, and the vehicle width direction outer end of the arm is connected to the wheel hub bearing portion And
The one end of the center of gravity movement restricting link is connected to the vehicle width direction central portion of the arm, and the other end of the center of gravity movement restricting link is connected to a central portion between the center of gravity and the wheel hub bearing portion. Suspension structure of the in-wheel motor drive according to claim 1. An in-wheel motor drive device including a wheel hub bearing portion and a motor portion outputting rotation to the wheel hub bearing portion, and having a center of gravity offset from the axis of the wheel hub bearing portion in the longitudinal direction of the vehicle;
A suspension structure of an in-wheel motor drive device, comprising: a pivot for attaching the in-wheel motor drive device to a vehicle body side member so as to be rotatable about a straight line passing through the center of gravity and parallel to the axis of the wheel hub bearing.   The suspension structure of an in-wheel motor drive according to any one of claims 1 to 5, wherein the wheel hub bearing portion is coupled to a front wheel of a vehicle and disposed forward of the center of gravity.   The suspension structure of an in-wheel motor drive according to any one of claims 1 to 6, wherein the in-wheel motor drive further includes a parallel two-shaft speed reduction mechanism. The suspension structure of an in-wheel motor drive according to any one of claims 1 to 7, wherein the center of gravity is at the same height as the axis of the wheel hub bearing in a normal state or at a position lower than the axis height.

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