Wheel drive system

Abstract

To provide a technology that miniaturizes an axial dimension of the whole wheel drive device while increasing a retention amount of lubricant by an oil catching member.SOLUTION: A wheel drive device includes: a rotor 60 including a wheel; a stationary body 62 relatively rotating with the rotor 60; a seal member 68 disposed between the rotor 60 and the stationary body 62 to seal an encapsulation space for a lubricant; and an oil catching member 80 for receiving the lubricant exceeding the seal member 68 and leaking therefrom. At least part of the oil catching member 80 is disposed in an axial recess part 84 formed in one of the rotor 60 and the stationary body 62.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to a wheel drive device.

Background Art

[0002] Patent Document 1 discloses a wheel drive device including a rotating body including a wheel, a fixed body that rotates relative to the rotating body, a seal member that seals an enclosed space for a lubricant disposed between the rotating body and the fixed body, and an oil receiving member that receives the lubricant leaking beyond the seal member.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The inventor of the present application has found a new idea for reducing the axial dimension of the entire wheel drive device while increasing the storage volume of the lubricant by the oil receiving member.

[0005] One object of the present disclosure is to provide a technique capable of reducing the axial dimension of the entire wheel drive device while increasing the storage volume of the lubricant by the oil receiving member.

Means for Solving the Problems

[0006] The wheel drive device of the present disclosure is a wheel drive device for driving a wheel, including a rotating body including a wheel, a fixed body that rotates relative to the rotating body, a seal member that seals an enclosed space for a lubricant disposed between the rotating body and the fixed body, and an oil receiving member that receives the lubricant leaking beyond the seal member, wherein at least a part of the oil receiving member is disposed in an axial recess formed in one of the rotating body and the fixed body.

Effects of the Invention

[0007] According to this disclosure, the storage volume of lubricant by the oil receiving member can be increased while reducing the axial dimensions of the entire wheel drive system. [Brief explanation of the drawing]

[0008] [Figure 1] This is a side cross-sectional view showing a power transmission device according to the first embodiment. [Figure 2] This is a side cross-sectional view showing a speed reducer according to the first embodiment. [Figure 3] This is a magnified view of a portion of Figure 2. [Figure 4] This is a diagram illustrating the propagation points of the lubricant. [Modes for carrying out the invention]

[0009] The embodiments are described below. The same reference numerals are used for identical components, and redundant explanations are omitted. For the sake of clarity, components are omitted, enlarged, or reduced in each drawing. The drawings should be viewed in accordance with the orientation of the reference numerals.

[0010] (First Embodiment) Refer to Figure 1. The wheel drive unit 10 is attached to a vehicle body 12 such as a transport cart and is used to drive the wheels 20. Examples of transport carts include AGVs (Automatic Guided Vehicles) and AMRs (Autonomous Mobile Robots). The applications of the wheel drive unit 10 of this disclosure are not limited to transport carts, but can be applied to various vehicles, such as forklifts and self-propelled service robots.

[0011] The wheel drive system 10 comprises a motor 16, a reduction gear 18 to which input rotation is received from the output shaft 16a of the motor 16, a wheel 20 to which output rotation is output from the reduction gear 18, and a mounting member 22 positioned between the motor 16 and the reduction gear 18 and attached to the vehicle body 12. Hereinafter, the direction along the rotation centerline CL1 of the wheel 20 will be referred to as the axial direction, and the radial and circumferential directions with the rotation centerline as the center of the circle will be referred to simply as the radial direction and circumferential direction, respectively.

[0012] The motor 16 comprises a cylindrical motor frame 16b and a pair of covers 16c and 16d that cover the open ends of the motor frame 16b. The pair of covers 16c and 16d include a load-side cover 16c positioned on the side of the reduction gear 18 and an anti-load-side cover 16d positioned on the opposite side of the reduction gear 18.

[0013] The mounting member 22 is annular in shape as a whole. The mounting member 22 has a mounting portion 22a for attaching to the vehicle body 12. In this embodiment, the mounting portion 22a protrudes radially outward from the motor 16. The mounting member 22 is attached to the vehicle body 12 by connecting it to the mounting portion 12a provided on the vehicle body 12 with bolts (not shown) while the mounting portion 22a abuts against the mounting portion 12a provided on the vehicle body 12. The mounting portion 12a may be provided on a component 12b attached to the vehicle body 12, or it may be provided on the vehicle body 12 itself.

[0014] Refer to Figure 2. The reduction gear 18 comprises an input shaft 24 to which input rotation is input from the output shaft 16a of the motor 16, a reduction mechanism 26 that reduces the input rotation transmitted from the input shaft 24 and converts it into output rotation, a casing 28 that houses the reduction mechanism 26, and carriers 30A and 30B arranged radially inward of the casing 28. The input shaft 24 is connected to the output shaft 16a of the motor 16 using a coupling member 32 such as a spline coupling.

[0015] The gearbox 18 of this embodiment is an eccentric oscillating gearbox. The input shaft 24 of this gearbox 18 is a crankshaft having at least one (two in this case) eccentric body 34. The eccentric phases of the multiple eccentric bodies 34 are offset from each other. The input shaft 24 and the eccentric bodies 34 may be separate or integrated.

[0016] The reduction mechanism 26 of the eccentric oscillating type speed reducer comprises an external gear 36 that oscillates on an eccentric body 34 and an internal gear 38 that meshes with the external gear 36. The external gear 36 is individually provided corresponding to each of the multiple eccentric bodies 34 and is supported so as to be rotatable relative to the eccentric bodies 34 via an eccentric body bearing 40. The internal gear 38 in this embodiment comprises an internal gear body 38a integrated with the casing 28 and an external pin 38b provided on the inner circumference of the internal gear body 38a that constitutes the internal teeth.

[0017] The carriers 30A and 30B are positioned on one axial side of the reduction mechanism 26. In this embodiment, the carriers 30A and 30B include a first carrier 30A positioned on one axial side and a second carrier 30B positioned on the other axial side. The carriers 30A and 30B are connected via connecting members 42 such as pins. The carriers 30A and 30B support the input shaft 24 via input bearings 44. A main bearing 46 is positioned between the casing 28 and the carriers 30A and 30B.

[0018] The reduction gear 18 described above includes an output member 48 that receives output rotation from the reduction mechanism 26 and outputs that output rotation, and a fixed member 50 that rotates relative to the output member 48 when the output member 48 rotates. The fixed member 50 is fixed to the vehicle body 12 via a mounting member 22. In this embodiment, the output member 48 is cylindrical as a whole. In this embodiment, the output member 48 is a casing 28, and the fixed member 50 is a carrier 30A, 30B. Alternatively, the output member 48 may be either the carrier 30A or 30B, and the fixed member 50 may be the casing 28.

[0019] The wheel 20 travels on a running surface by rotating due to the output rotation output from the output member 48. The running surface is, for example, the floor surface of a building, a rail, or the like. The wheel 20 includes a wheel member 52 connected to the output member 48 using bolts or the like, and a grounding member 54 attached to the outer peripheral portion of the wheel member 52. The wheel member 52 is generally cylindrical. The grounding member 54 contacts the running surface when the wheel 20 travels. The grounding member 54 of the present embodiment is a tire. The specific example of the grounding member 54 is not particularly limited, and in addition to this, an omnidirectional wheel roller, a mecanum wheel roller, or the like may also be used.

[0020] The attachment member 22 functions as an adapter that connects the motor 16 and the speed reducer 18. The attachment member 22 is connected to a flange portion (not shown) provided on the load side cover 16c of the motor 16 using bolts (not shown). The attachment member 22 is connected to the fixing member 50 of the speed reducer 18 using a bolt B. The attachment member 22 is connected to the fixing member 50 in a state where its side surface abuts against the side surface of the fixing member 50. Thereby, the attachment member 22 is attached to the vehicle body 12 while supporting the motor 16 and the speed reducer 18 respectively. A through hole 22b penetrating in the axial direction is provided in the attachment member 22, and the output shaft 16a of the motor 16 and the input shaft 24 of the speed reducer 18 are inserted into the through hole 22b.

[0021] The attachment member 22 and the motor 16 include a motor side in-roll portion 56 where a first inner peripheral in-roll surface 56a and a first outer peripheral in-roll surface 56b are in-roll fitted. In the present embodiment, the first inner peripheral in-roll surface 56a is provided on the attachment member 22, and the first outer peripheral in-roll surface 56b is provided on the load side cover 16c of the motor 16, but the reverse may also be true. The attachment member 22 and the fixing member 50 of the speed reducer 18 include a speed reducer side in-roll portion 58 where a second inner peripheral in-roll surface 58a and a second outer peripheral in-roll surface 58b are in-roll fitted. In the present embodiment, the second inner peripheral in-roll surface 58a is provided on the fixing member 50, and the second outer peripheral in-roll surface 58b is provided on the attachment member 22, but the reverse may also be true.

[0022] The operation of the above-described wheel drive device 10 will be described. When input rotation is input from the motor 16 to the input shaft 24 of the speed reducer 18, the speed reduction mechanism 26 operates. When the speed reduction mechanism 26 operates, output rotation reduced with respect to the input rotation is transmitted from the speed reduction mechanism 26 to the output member 48. When the output rotation is transmitted to the output member 48, the wheel 20 rotates together with the output member 48, and the wheel 20 travels on the running surface.

[0023] When the eccentric swing type speed reducer 18 is used as in the present embodiment, when the input shaft 24 (crankshaft) rotates, the outer gear 36 swings such that the center of the outer gear 36 rotates around the rotation center line CL1 of the output member 48 by the eccentric body 34. When the outer gear 36 swings, the meshing position of the outer gear 36 and the inner gear 38 changes in the circumferential direction. Along with this, every time the input shaft 24 makes one rotation, one of the outer gear 36 and the inner gear 38 (here, the inner gear 38) rotates by the difference in the number of teeth between the outer gear 36 and the inner gear 38. This rotation component is transmitted as output rotation to the output member 48.

[0024] The above-described wheel drive device 10 includes a rotating body 60 including the wheel 20, a fixed body 62 that rotates relative to the rotating body 60 when the rotating body 60 rotates, and a seal member 68 that seals an enclosed space 66 for a lubricant 64 disposed between the rotating body 60 and the fixed body 62. In the present embodiment, the rotating body 60 is the wheel 20 and the output member 48 (casing 28), and the fixed body 62 is the fixing member 50 (carriers 30A, 30B) and the mounting member 22.

[0025] The enclosed space 66 is provided as an internal space of the wheel drive device 10. In the enclosed space 66 of the present embodiment, the speed reduction mechanism 26 of the speed reducer 18 is accommodated, and is provided at least in a location surrounded by the casing 28 and the carriers 30A, 30B. The enclosed space 66 of the present embodiment is sealed by, in addition to the seal member 68, a seal cover 70 that closes the anti-motor side opening of the cylindrical casing 28 and an oil seal 16e disposed between the output shaft 16a of the motor 16 and the load side cover 16c. The lubricant 64 is used for lubricating the speed reduction mechanism 26. The lubricant 64 of the present embodiment is lubricating oil, but grease or the like may also be used.

[0026] In this embodiment, the sealing member 68 is positioned between the casing 28, which is part of the rotating body 60, and the second carrier 30B, which is part of the stationary body 62. The sealing member 68 is a contact-type seal such as a lip seal or O-ring, and in this case, it is a lip seal. The sealing member 68 is made of an elastic material such as rubber.

[0027] Refer to Figures 2 and 3. The wheel drive unit 10 includes an oil receiving member 80 that receives lubricant 64 that has leaked beyond the sealing member 68. Here, "leaking beyond the sealing member 68" means that the lubricant 64 leaks out of the lubricant 64 sealing space 66 through the location where the sealing member 68 is positioned.

[0028] The oil receiving member 80 is provided on the mounting member 22, which is part of the fixed body 62. In this embodiment, the oil receiving member 80 is integrally molded as part of the same material as the mating member 82 (here, the mounting member 22) on which the oil receiving member 80 is provided, but it may also be provided separately from the mating member 82.

[0029] The oil receiving member 80 of this embodiment comprises an axial wall portion 80a extending axially from the mating member 82 on which the oil receiving member 80 is provided, and an outer wall portion 80b protruding radially inward from the outer end of the axial wall portion 80a. The oil receiving member 80 as a whole is provided so as to protrude axially from the mating member 82.

[0030] At least a portion of the oil receiving member 80 is positioned within an axial recess 84 formed in one of the rotating body 60 and the stationary body 62 (in this case, the rotating body 60). Hereinafter, the rotating body 60 and the stationary body 62 in which the axial recess 84 is formed will be referred to as the recess-forming body 86. The axial recess 84 is formed radially outward from the seal member 68 in the recess-forming body 86. The axial recess 84 is recessed from the side surface of the recess-forming body 86 toward one axial side (in this case, the side opposite the motor) and is continuous in an annular shape. The axial recess 84 forms a radial gap 84c between its upper surface 84a and lower surface 84b, and the oil receiving member 80 is positioned within this radial gap 84c. In this embodiment, the axial recess 84 is formed between the output member 48, which is part of the rotating body 60, and the wheel member 52.

[0031] The oil receiving member 80 is provided with a concave receiving recess 88 for receiving the lubricant 64. In this embodiment, the receiving recess 88 is formed on the inside of the axial wall portion 80a and the outer wall portion 80b. In this embodiment, the receiving recess 88 is configured as an annular continuous groove. The receiving recess 88 constitutes an oil reservoir 90 that stores the lubricant 64 received by the oil receiving member 80. In this embodiment, the oil reservoir 90 is provided below the lower end position Pa at the inner circumferential end of the outer wall portion 80b of the oil receiving member 80.

[0032] The receiving recess 88 comprises a bottom surface 88a and a pair of side surfaces 88b and 88c provided on both sides axially relative to the bottom surface 88a. The pair of side surfaces 88b and 88c include an inner surface 88b on the side of the mating member 82 which is integrally provided with the oil receiving member 80, and an outer surface 88c on the opposite side from the mating member 82. In this embodiment, the inner surface 88b is formed by the mating member 82, and the outer surface 88c is formed by the oil receiving member 80. Thus, the receiving recess 88 of the oil receiving member 80 only needs to be formed in part by the oil receiving member 80, and a part of it may be formed by the mating member 82.

[0033] The wheel drive unit 10 includes a lubricant propagation member 91 through which lubricant 64 leaking from the seal member 68 is propagated. In Figure 3, the propagation path of this lubricant 64 is schematically shown by the arrow Da. In this embodiment, the lubricant propagation member 91 is a casing 28 and forms the aforementioned axial recess 84. The lubricant 64 leaking from the seal member 68 is propagated along the outer surface of the lubricant propagation member 91, at least by its own weight. The lubricant propagation member 91 includes an outer surface portion 91a located radially outward from the seal member 68, and an axial surface portion 91c extending axially inward from the outer peripheral edge portion 91b of the outer surface portion 91a, as points for the propagation of the lubricant 64. The axial surface portion 91c is provided with an upper surface portion 84a of the axial recess 84 that forms a radial gap 84c. The oil receiving member 80 is positioned below the point where the lubricant 64 propagates, and can receive the lubricant 64 that drips down from that point.

[0034] The lubricant propagation member 91 includes a guide portion 92 provided on the axial surface portion 91c, which is located radially inward from the oil receiving member 80. The guide portion 92 includes a large outer diameter portion 92a provided on the axial surface portion 91c and a small outer diameter portion 92b provided axially inward from the large outer diameter portion 92a on the axial surface portion 91c. The outer diameter R92b of the small outer diameter portion 92b is smaller than the outer diameter R92a of the large outer diameter portion 92a. In this embodiment, the guide portion 92 is constructed by providing a recess at the location of the small outer diameter portion 92b on the axial surface portion 91c. Alternatively, it may be constructed by providing a convex portion at the location of the large outer diameter portion 92a on the axial surface portion 91c, or by gradually reducing the outer diameter of the axial surface portion 91c toward the axial inward direction. In this embodiment, the large outer diameter portion 92a and the small outer diameter portion 92b constituting the guide portion 92 are provided over the entire circumference of the axial surface portion 91c.

[0035] When the lubricant 64 attempts to propagate axially inward on the axial surface portion 91c of the lubricant propagation member 91, it becomes difficult for the lubricant 64 to move from the large outer diameter portion 92a to the small outer diameter portion 92b. Therefore, by preventing the propagation of the lubricant 64 at the large outer diameter portion 92a of the guide portion 92, the lubricant 64 can be held in the large outer diameter portion 92a of the guide portion 92. The guide portion 92 can guide the lubricant 64 held by itself to the oil receiving member 80 in direction Db by separating it through its own weight, rotation, etc. In other words, the guide portion 92 of the lubricant propagation member 91 holds the lubricant 64 by preventing its propagation at a position facing the oil receiving member 80 radially inward, and guides the held lubricant 64 to the oil receiving member 80 by separating it.

[0036] This reduces the amount of lubricant 64 that attempts to pass axially inward at a position in the lubricant propagation member 91 that is radially inward of the oil receiving member 80. In this example, as indicated by arrow Dc, the lubricant 64 that attempts to pass axially inward passes through the upper surface 84a → bottom → lower surface 84b → side surface of the wheel member 52 of the axial recess 84 before leaking into the external space 94. In other words, after passing through a position in the lubricant propagation member 91 that is radially inward of the oil receiving member 80, it passes through the outer surface of a member (in this case, the wheel member 52) that is integrated with the lubricant propagation member 91 below the oil receiving member 80 before leaking into the external space 94. By providing the aforementioned guide portion 92, the amount of lubricant 64 that leaks into the external space 94 can be reduced.

[0037] Refer to Figure 4. In this figure, hatching is applied to a portion of the propagation points 100 of the lubricant 64 leaking from the seal member 68. In this embodiment, the lubricant propagation member 91 becomes part of the rotating body 60. Therefore, the lubricant 64 leaking from the seal member 68 is propagated by the rotation of the lubricant propagation member 91 to a range that is continuous in the circumferential direction from the propagation points of the lubricant 64 due to its own weight on the lubricant propagation member 91. The propagation points 100 of the lubricant 64 due to this rotation include the outer surface portion 91a and the axial surface portion 91c of the lubricant propagation member 91 that are radially outside the seal member 68. In this embodiment, the oil receiving member 80 is provided in an annular shape so as to surround the propagation points 100 of the lubricant 64, which are part of the lubricant propagation member 91, from the radial outside. As a result, when the rotation of the rotating body 60 causes the lubricant 64 to splash from the lubricant propagation point 100 of the lubricant propagation member 91, the lubricant 64 can be received by the oil receiving member 80. Consequently, leakage of the splashed lubricant 64 into the external space 94 can be suppressed.

[0038] The effects of the wheel drive system 10 described above will now be explained.

[0039] At least a portion of the oil receiving member 80 is positioned within an axial recess 84 formed in either the rotating body 60 or the stationary body 62. Therefore, compared to the case where an axial recess 84 is not formed in the recess-forming body 86, the axial dimension L80 (see Figure 3) of the oil receiving member 80 can be increased by the amount by which the oil receiving member 80 is positioned within the axial recess 84, and consequently, the lubricant storage volume can be increased. Increasing the lubricant storage volume here means increasing the volume of the oil reservoir 90 in the oil receiving member 80. Furthermore, compared to the case where the same axial dimension L90 of the oil receiving member 80 is secured without forming an axial recess 84 in the recess-forming body 86, the overall axial dimension of the wheel drive device 10 can be reduced. In other words, the lubricant storage volume provided by the oil receiving member 80 can be increased while reducing the overall axial dimension of the wheel drive device 10.

[0040] The oil receiving member 80 is provided on the mounting member 22. This allows a portion of the heat generated by the motor 16 and the reduction gear 18 and transferred to the mounting member 22 to be transferred from the mounting member 22 to the oil receiving member 80. Therefore, the surface area contributing to heat dissipation to the air can be increased by the amount of the oil receiving member 80. Consequently, the amount of heat released directly into the air from the mounting member 22 and the oil receiving member 80 without going through the vehicle body 12 can be increased, improving the heat dissipation performance of the wheel drive unit 10. In addition, since the amount of heat transferred from the mounting member 22 to the vehicle body 12 can be reduced, the impact of heat generated by the motor 16, etc. on the vehicle body 12 can be reduced.

[0041] Thus, the oil receiving member 80 in this embodiment functions as a heat dissipation member that receives a portion of the heat transferred to the mounting member 22 and dissipates it into the external space 94. From this viewpoint, it is preferable that a portion of the oil receiving member 80 be provided in a position that is exposed to the external space 94 when viewed from the radial direction. In this embodiment, the portion of the oil receiving member 80 refers to the axial wall portion 80a of the oil receiving member 80.

[0042] The oil receiving member 80 is provided on the fixed body 62. This allows the oil receiving member 80 to remain stationary when the wheel 20 rotates, thus enabling the oil receiving member 80 to stably retain the lubricant 64 without spilling it.

[0043] Next, other features of the wheel drive unit 10 will be described. Refer to Figure 4. The wheel drive unit 10 includes a lubricant transmission member 91 which is part of the rotating body 60 and an opposing member 102 which is positioned opposite to it in the axial direction. In this embodiment, the opposing member 102 is a mounting member 22 on which an oil receiving member 80 is provided and is part of the stationary body 62. The opposing member 102 is positioned opposite to both the lubricant transmission member 91 and the sealing member 68 in the axial direction. The bottom surface 88a of the oil receiving member 80 is inclined radially inward as it approaches the opposing member 102 in the axial direction. The advantages of this will be explained.

[0044] Consider the case where, above the sealing member 68, the lubricant 64 that is splashed upward from the axial surface 91c of the lubricant propagation member 91 due to the rotation of the rotating body 60 is received by the oil receiving member 80. In Figure 4, two propagation paths of the lubricant 64 splashed upward in this way are schematically shown by arrows Dd and De. The propagation path in this embodiment is shown by arrow Dd, and the propagation path in the reference embodiment is shown by arrow De. In Figure 4, the solid arrows indicate that the lubricant 64 propagates in areas visible in Figure 4, and the dashed arrows indicate that the lubricant 64 propagates in areas hidden in Figure 4.

[0045] The reference structure (not shown) assumes that the bottom surface 88a of the oil receiving member 80 is not inclined but parallel to the axial direction. In this case, consider the scenario where the lubricant 64 that splashes upward after being received by the bottom surface 88a of the oil receiving member 80 propagates in the opposite direction axially from the opposing member 102. In this case, as shown by arrow De in Figure 4, the lubricant 64 drips downward from the outer surface 88c of the oil receiving member 80, returning to the axial surface 91c of the lubricant propagation member 91. Consequently, after propagating from the top to the bottom of the axial surface 91c of the lubricant propagation member 91, the lubricant 64 propagates even further below the oil receiving member 80, increasing the risk of lubricant 64 leaking into the external space 94.

[0046] In this respect, according to this embodiment, the bottom surface 88a of the oil receiving member 80 is inclined to move radially inward as it approaches the opposing member 102. Therefore, as indicated by arrow Dd, the lubricant 64 received by the bottom surface 88a of the oil receiving member 80 above the sealing member 68 can be guided toward the opposing member 102 by its own weight. The lubricant 64 guided toward the opposing member 102 in this way propagates downward along the side surface of the opposing member 102 before being guided to the oil reservoir 90 of the oil receiving member 80. In other words, when the lubricant 64 that has splashed upward is received by the bottom surface 88a of the oil receiving member 80, it can propagate along the side surface of the opposing member 102 and then be guided to the oil reservoir 90 of the oil receiving member 80. Consequently, the situation in which the lubricant 64 that has splashed upward propagates toward the opposite side from the opposing member 102 and leaks out into the external space 94 can be avoided.

[0047] Next, we will describe the transformation forms of each component described so far.

[0048] The specific examples of the speed reducer 18 are not particularly limited, and various speed reduction mechanisms can be applied. In addition to the eccentric oscillating speed reducer, other examples include a flexible meshing speed reducer, a simple planetary gear speed reducer, a traction drive, etc. The type of eccentric oscillating speed reducer is not particularly limited. As an example, in this embodiment, a center crank type in which the crankshaft (input shaft 24) is positioned on the rotational centerline of the wheel 20 has been described. In addition, a distribution type in which multiple crankshafts are positioned radially offset from the rotational centerline of the wheel 20 is also possible. The type of flexible meshing speed reducer is not particularly limited, and in addition to a cylindrical type with two internal gears, any of the following types are possible: a cup type with one internal gear, a top hat type, etc.

[0049] The axial recess 84 may be formed in either the rotating body 60 or the stationary body 62. The axial recess 84 may also be formed in the stationary body 62 instead of the rotating body 60. This assumes, for example, that the axial recess 84 is formed in the mounting member 22 which is the stationary body 62. In addition, the axial recess 84 may be formed in only one of the output member 48 and the wheel member 52 which are the rotating body 60. Furthermore, the output member 48 and the wheel member 52 may be provided as separate parts as in the embodiment, or they may be integrally molded.

[0050] The position and shape of the oil receiving member 80 are not particularly limited, as long as they can receive lubricant that has leaked beyond the sealing member 68. For example, the oil receiving member 80 may be positioned only below the point where the lubricant 64 is propagated by its own weight in the lubricant propagation member 91. In this case, the oil receiving member 80 may, for example, have a continuous arc shape over a circumferential range of about half a turn below the point where the lubricant 64 is propagated by its own weight. The bottom surface 88a of the oil receiving member 80 does not have to be inclined, or it may be inclined radially outward as it approaches the opposing member 102.

[0051] In the example described, the mating member 82 on which the oil receiving member 80 is provided is part of the stationary body 62, but it may also be part of the rotating body 60. This assumes, for example, that the oil receiving member 80 is provided on either the output member 48 or the wheel member 52, which are part of the rotating body 60.

[0052] The lubricant transmission member 91 may be a member integrated with the casing 28 (for example, a wheel member 52) instead of the casing 28. Also, if the lubricant transmission member 91 is the casing 28, the casing 28 may be part of either the rotating body 60 or the stationary body 62.

[0053] The embodiments and variations described above are illustrative. The abstract technical ideas derived from them should not be interpreted restrictively to the content of the embodiments and variations. Many design changes, such as changes, additions, and deletions of components, are possible in the embodiments and variations. In the embodiments described above, the content that allows for such design changes is emphasized with the notation "embodiment." However, design changes are also permitted in content without such notation. The hatching applied to the cross-sections in the drawings does not limit the material to which the hatching is applied. The structures and numerical values ​​mentioned in the embodiments and variations naturally include those that can be considered identical when considering manufacturing tolerances, etc.

[0054] Any combination of the above components is also valid. For example, any description of the embodiment and other modified forms may be combined with a modified form. In an embodiment, a component composed of a single member may be composed of multiple members. Similarly, in an embodiment, a component composed of multiple members may be composed of a single member. [Explanation of Symbols]

[0055] 10...Wheel drive unit, 12...Vehicle body, 16...Motor, 18...Reduction gear, 20...Wheel, 22...Mounting member, 48...Output member, 52...Wheel member, 60...Rotating body, 62...Stationary body, 64...Lubricant, 66...Sealing space, 68...Seal member, 80...Oil receiving member, 84...Axial recess, 92...Guide part, 102...Opposite member.

Claims

1. A wheel drive system that drives wheels, A rotating body including the aforementioned wheels, A stationary body that rotates relative to the aforementioned rotating body, A sealing member is disposed between the rotating body and the stationary body to seal the space for sealing the lubricant, The system includes an oil receiving member that receives the lubricant that has leaked beyond the sealing member, A wheel drive device in which at least a portion of the oil receiving member is positioned in an axial recess formed in one of the rotating body and the stationary body, axially inward from the axially outer end of the sealing member.

2. A guide portion is provided at a position facing radially inward from the oil receiving member, and guides the lubricant to the oil receiving member, The wheel drive device according to claim 1, wherein the guide portion comprises a large outer diameter portion and a small outer diameter portion provided axially inward from the large outer diameter portion and having a smaller outer diameter than the large outer diameter portion.

3. The wheel drive device according to claim 1 or 2, wherein the oil receiving member is provided in an annular shape.

4. The system includes a lubricant propagation member that propagates the lubricant leaking from the sealing member and becomes part of the rotating body, The wheel drive device according to claim 3, wherein the oil receiving member is provided so as to surround a part of the lubricant propagation member from the radially outer side, axially inward from the axially outer end of the sealing member.

5. A wheel drive device for driving wheels, A rotating body including the aforementioned wheels, A stationary body that rotates relative to the aforementioned rotating body, A sealing member is disposed between the rotating body and the stationary body to seal the space for sealing the lubricant, An oil receiving member that receives the lubricant that has leaked beyond the sealing member, A lubricant propagation member, which receives the lubricant leaked from the sealing member and becomes part of the rotating body, The device comprises the lubricant propagation member and an opposing member arranged axially opposite to it, on which the oil receiving member is provided. At least a portion of the oil receiving member is disposed within an axial recess formed in one of the rotating body and the stationary body. The oil receiving member is provided in an annular shape so as to surround a part of the lubricant propagation member. The bottom surface of the oil receiving member is inclined radially inward as it approaches the opposing member in the axial direction, in a wheel drive device.

6. It is equipped with a mounting member that is positioned between the motor and the reduction gear and attached to the vehicle body, The oil receiving member is provided on the mounting member, The sealing member is positioned axially with respect to the sealed space on the side of the motor, The wheel drive device according to claim 1 or 2, further comprising a seal cover that closes the opening on the axial side of the enclosed space opposite to the motor, thereby sealing the enclosed space.

7. The wheel drive device according to claim 1 or 2, wherein the oil receiving member is provided on the fixed body.

8. The rotating body comprises a wheel member and an output member that rotates integrally with the wheel member. The wheel drive device according to claim 1 or 2, wherein the axial recess is provided between the wheel member and the output member.

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