Vehicle drive system

Abstract

A drive device (1) has a motor (10), a reduction gear mechanism (11) lubricated with lubricating oil (90), and a housing (3) that accommodates at least one section of the reduction gear mechanism (11). The reduction gear mechanism (11) has a pinion (21) and a reduction gear (22). The reduction gear (22) has a cylindrical gear section (221) with a large diameter, the diameter of which is larger than that of the pinion (21), a shaft section (222) with an outer diameter smaller than that of the large-diameter gear section (221), and a disk section (223) located between the large-diameter gear section (221) and the shaft section (222). The pinion (21) engages with the large-diameter gear section (221).A part of the housing (3) is arranged inside the large diameter part (221), and in this part of the housing (3) a storage part (301) for storing the lubricating oil (90) is formed.

Description

Technical field

[0001] The present invention relates to a vehicle drive device that drives wheel-tire assemblies of a vehicle. State of the art

[0002] A so-called wheel hub motor system has been proposed as a drive system for electric vehicles that use a motor as a power source. In this system, wheel-tire assemblies are driven by drive devices located within the wheels of the wheel-tire assemblies. Vehicles using this type of drive system exhibit high acceleration response due to the short distance between the drive sources and the wheel-tire assemblies. Furthermore, maneuverability can be improved by independently controlling the drive force of the right and left wheel-tire assemblies.

[0003] Patent literature 1 describes a motor drive unit that reduces the output speed of a motor using a high-speed reduction mechanism and a low-speed reduction mechanism, driving a wheel-tire assembly so that it rotates with the motor's increased running torque resulting from this reduction. The high-speed reduction mechanism consists of a parallel-shaft gear pair, and the low-speed reduction mechanism consists of a planetary gear reduction mechanism. The parallel-shaft gear pair and the planetary gear reduction mechanism are housed in a reduction chamber surrounded by a motor housing and a reduction housing.An oil reservoir is provided at the bottom of the reduction chamber and is divided by a partition plate into a reservoir on the high-speed reduction mechanism side and a reservoir on the low-speed reduction mechanism side. The parallel shaft gear pair is lubricated by the oil stored in the reservoir on the high-speed reduction mechanism side, and the planetary gear mechanism is lubricated by the oil stored in the reservoir on the low-speed reduction mechanism side. CITATION LIST Patent literature

[0004] Patent literature 1: JP 2015 - 132 315 A Summary of the invention: Technical problem

[0005] A wheel hub motor system drive device is located within a wheel of a wheel-tire assembly, and therefore its size is essential. In a configuration described in patent literature 1, the oil reservoir is located in the lower section of the reduction gear chamber, which results in larger motor and reduction gear housings. Furthermore, this increase in size increases the device's weight, and there is concern that this weight increase could negatively impact its electric range.

[0006] Accordingly, it is an object of the present invention to provide a vehicle drive device that can be made smaller and lighter. Solution to the problem

[0007] To solve the aforementioned problem, the present invention provides a vehicle drive device for driving a wheel-tire assembly of a vehicle, comprising a motor, an oil-lubricated reduction gear mechanism, and a housing that accommodates at least a portion of the reduction gear 22, wherein the reduction gear has an input gear and an output gear, the output gear comprising a large-diameter gear section having a cylindrical shape with a diameter larger than the diameter of the input gear, a shaft section whose outer diameter is smaller than the outer diameter of the large-diameter gear section, and a disk section provided between the large-diameter gear section and the shaft section, wherein the input gear engages with the large-diameter gear section.wherein a part of the housing is arranged on an inner side of the large-diameter gear section and wherein a reservoir for storing the lubricating oil is provided in that part of the housing. Advantageous effects of the invention

[0008] According to the present invention, the vehicle drive device can be made smaller and lighter. Brief description of the drawings Fig. Figure 1 is a perspective view showing a drive device, a wheel-tire assembly, a fastening element, a brake disc and a brake device according to an embodiment of the present invention. Fig. Figure 2 is a cross-sectional view of the drive device and its surroundings. Fig. 3 is a partially enlarged view of Fig. 2. Fig. Figure 4 is a perspective view showing a retaining element and a support shaft element. Fig. 5 is a perspective view that represents a linking element. Fig. Figure 6 is a cross-sectional view of the drive device, showing a cross-section of a planetary gear mechanism perpendicular to an axial direction, looking from the inside of the vehicle to the outside of the vehicle. Fig. Figure 7 is a perspective cross-sectional view representing an exterior element. Fig. 8A is a configuration scheme from which a housing can be seen. Fig. 8B is a cross-sectional view along line AA in Fig. 8A. Fig. Figure 9 is a perspective view of the case. Fig. 10A is a diagram that illustrates a configuration of a reduction gear 22. Fig. Figure 10B is a cross-sectional view of the reduction gear 22, showing a cross-section of a shaft section of the reduction gear 22 from the outside of the vehicle to the inside of the vehicle. Fig. Figure 11 is a cross-sectional view showing a housing and a reduction gear according to a modification. Description of embodiments (design form)

[0009] One embodiment of the present invention is described with reference to the drawings. It should be noted that the embodiment described below is presented as a suitable concrete example for the implementation of the present invention and that, although some parts of the embodiment specifically illustrate various technically advantageous aspects, the technical scope of the present invention is not limited to such specific aspects.

[0010] Fig. Figure 1 is a perspective view showing a drive device 1 according to the embodiment of the present invention, a wheel-tire assembly 91 driven by the drive device 1, a mounting element 92 to which the drive device 1 is attached, a brake disc 93 which rotates integrally with the wheel-tire assembly 91, and a brake device 94. The wheel-tire assembly 91 has a wheel 911 made of metal and a tire 912 made of rubber, which is attached to the wheel 911. The mounting element 92 is connected to a vehicle body via a suspension arm, a shock absorber, and a suspension spring. The brake device 94 generates a braking force by pressing brake pads against the brake disc 93.

[0011] The operation of each component of the drive device 1 is lubricated by lubricating oil sealed within the drive device 1. The configuration and operation of the drive device 1 are described below, followed by a description of the flow of lubricating oil within the drive device 1. (Lubricating structure of the drive device 1)

[0012] Fig. Figure 2 is a cross-sectional view of the drive device 1 and its surroundings. Fig. 3 is a partially enlarged view of the Fig. 2. In the Fig. 2 corresponds to "upwards" in the drawing in the vertical direction and "downwards" in the drawing in the vertical direction. In the following description, the terms "up" and "downwards" refer to "up" and "downwards" in the vertical direction in a state in which the drive device 1 is installed in the vehicle.

[0013] In the Fig. Figure 2 shows a pivot axis O91 of the wheel-tire assembly 91, represented by a long dashed line and a short dashed line. The fastening element 92 has a mounting hole 920 formed within it for attaching the drive device 1. The mounting hole 920 is a circular hole that is coaxial with the pivot axis O91 and passes through the fastening element 92. In the following, the wheel-tire assembly 91 side of the fastening element 92 is referred to as the "vehicle exterior" and the opposite side as the "vehicle interior".

[0014] The drive device 1 comprises, as functional components, a motor 10, a reduction gear mechanism 11, and a planetary gear mechanism 12, which reduces the speed of the motor 10, as well as a hub unit 13, which carries the wheel-tire assembly 91. The planetary gear mechanism 12 and the hub unit 13 are aligned and coaxially arranged along the axis of rotation O91. The reduction gear mechanism 11 is positioned between the motor 10 and the planetary gear mechanism 12. The reduction gear mechanism 11 acts as a primary reduction mechanism, reducing the output rotations of the motor 10. The planetary gear mechanism 12 has a plurality of planet gears 4 and acts as a secondary reduction mechanism, further reducing the output rotations of the reduction gear mechanism 11.

[0015] The reduction gear mechanism 11, the planetary gear mechanism 12, and the hub unit 13 are lubricated with a lubricating oil 90. The lubricating oil 90 is produced by adding additives to a base oil, which is based, for example, on mineral oil or synthetic oil, in order to improve and maintain its lubricating performance.

[0016] The drive device 1 also comprises as its main components a pinion 21, which is attached to an output shaft 101 of the motor 10, a large-diameter reduction gear 22, which meshes with the pinion 21, a housing 3, which accommodates at least part of the reduction gear mechanism 11, a plurality of planet gears 4, which constitute the planetary gear mechanism 12, a carrier 5, which holds the plurality of planet gears 4, an inner element 6, which rotates integrally with the carrier 5, an outer element 7, which is fitted into and secured in the mounting hole 920, a plurality of rolling elements 80, which are arranged between the inner element 6 and the outer element 7, and bearings 81 to 86.

[0017] As from the Fig. As can be seen in Figure 1, the housing 3 is attached to the mounting element 92 by a plurality of screws 871. The motor 10 is an electric motor that generates a torque to rotate the output shaft 101 by means of a drive current supplied by a control unit (not shown in the illustration), and more precisely, is, for example, an internal rotor permanent magnet synchronous motor or an external rotor permanent magnet synchronous motor. The motor 10 is attached to the housing 3 by a plurality of screws 872.

[0018] The reduction gear mechanism 11 is configured to have the pinion 21 and the reduction gear 22. The pinion 21 corresponds to an input gear according to the present invention, and the reduction gear 22 corresponds to an output gear according to the present invention. The reduction gear mechanism 11 reduces the rotational speed of the pinion 21 to increase the torque of the motor 10 and transmits the torque from the reduction gear 22 to the planetary gear mechanism 12.

[0019] The planetary gear mechanism 12 is composed of a plurality of planet gears 4, the carrier 5, and a portion of the outer element 7. The hub unit 13 is composed of the inner element 6, a plurality of rolling elements 80, and a portion of the outer element 7. The planetary gear mechanism 12 further reduces the output rotations of the motor 10, which are reduced by the reduction gear mechanism 11, and transmits them from the carrier 5 to the inner element 6. The inner element 6 is rotatably mounted on the outer element 7 by a plurality of rolling elements 80 and rotates integrally with the wheel-tire assembly 91. The components of the drive device 1 are described in detail below.

[0020] The pinion 21 is mounted on the output shaft 101 of the motor 10 in such a way that it cannot rotate relative to the output shaft 101. An end section of the pinion 21 on the inside of the vehicle is rotatably mounted by the bearing 81 held in the housing 3. The end section of the pinion 21 on the outside of the vehicle is rotatably mounted by the bearing 82 held by the fastening element 92. The pinion 21 has a small-diameter gear element 21a, which consists of a spur gear between the bearing 81 and the bearing 82. Fig. Figure 2 shows a pitch circle diameter P21 of the gear element 21a with a small diameter. Fig. Figure 2 also shows a rotation axis O21 of the pinion 21 by a long dashed line and a short dashed line.

[0021] The reduction gear 22 has in one piece a large-diameter gear section 221, which has a cylindrical shape with a larger diameter than the pinion 102, a shaft section 222 with an outer diameter smaller than that of the large-diameter gear section 221, and a disk section 223, which is provided between the large-diameter gear section 221 and the shaft section 222. Fig. 2 is a rotation axis O 22 The reduction gear 22 is represented by a long dashed line and a short dashed line. The axis of rotation O 22 The axis of rotation of the reduction gear 22 coincides with the axis of rotation O91 of the wheel-tire assembly 91. The axis of rotation O21 of the pinion 21 runs parallel to the axis of rotation O 22 of the reduction gear 22. The pinion 21 is below the axis of rotation O. 22of the reduction gear 22 and engages with the section 221 of the large-diameter gear at the lower end of the reduction gear 22. In the following, a direction parallel to the axis of rotation O is described. 22 of the reduction gear 22 is referred to as the "axial direction".

[0022] The large-diameter gear section 221 extends axially from an outer end section of the disc section 223 towards the outside of the vehicle. The large-diameter gear section 221 is formed with a large-diameter gear element 221a, which consists of a spur gear and meshes with the small-diameter gear element 21a of the pinion 21. The pitch circle diameter P221 of the large gear element 221a is larger than the pitch circle diameter P21 of the small gear element 21a.

[0023] The shaft section 222 extends axially from an inner end section of the disk section 223 to the outer side of the vehicle and is arranged in a central section of the planetary gear mechanism 12. The plurality of planet gears 4 is arranged on an outer circumference of the shaft section 222. The shaft section 222 is formed with a sun gear element 222a, which meshes with the plurality of planet gears 4. The sun gear element 222a is constructed of helical gears whose tooth flanks are inclined relative to the axial direction. The pitch circle diameter P222 of the sun gear element 222a is smaller than the pitch circle diameter P221 of the larger-diameter gear element 221a.

[0024] The carrier 5 is configured to have a retaining element 51 with a plurality of retaining sections 50 formed thereon, each holding the plurality of planet gears 4, a connecting element 52 that prevents the planet gears 4 from slipping out of the retaining sections 50 and that also connects the retaining element 51 to the inner element 6, a plurality of support shaft elements 53 that are arranged between the retaining element 51 and the connecting element 52 and support each of the plurality of planet gears 4, and a plurality of screws 54 that fasten the retaining element 51 to the connecting element 52.

[0025] Fig. Figure 4 is a perspective view showing the retaining element 51 and a support shaft element 53. Fig. Figure 5 is a perspective view showing the connecting element 52. Fig. Figure 6 is a cross-sectional view of the drive device 1, showing a cross-section of the planetary gear mechanism 12 perpendicular to the axial direction, viewed from the inside of the vehicle to the outside of the vehicle. Fig. Figure 7 is a perspective cross-sectional view showing the outer element 7.

[0026] The retaining element 51 integrally comprises a base section 511, which is disc-shaped, a flange section 512, which is provided at an end section of the base section 511 on the inside of the vehicle, and a plurality of leg shaft sections 513, which are designed and extend axially such that they project from the base section 511 towards the outside of the vehicle. A through-hole 511a is formed at the center point of the base section 511, into which the shaft section 222 of the reduction gear 22 is inserted. The flange section 512 is annular and projects radially from an outer circumferential surface 511b of the base section 511.

[0027] The plurality of leg shaft sections 513 are provided at equal intervals along a circumferential direction of the base section 511, and the retaining sections 50 are formed between the plurality of leg shaft sections 513. In the present embodiment, the planetary gear mechanism 12 has three planet gears 4, and the retaining element 51 is provided with three leg shaft sections 513. Each of the leg shaft sections 513 is formed with a hole 513a through which the screw 54 can be inserted. As can be seen from the Fig. As can be seen in Figure 2, the screw 54 has a cylindrical section 541 which is inserted into the hole 513a, a head section 542 whose diameter is larger than that of the insertion section 541, and an external thread section 543 which is screwed into the connecting element 52.

[0028] The support shaft element 53 integrally comprises a large-diameter section 531, which is inserted through the central section of the planetary gear 4, and a pair of small-diameter sections 532 and 533, the small-diameter sections 532 and 533 each being provided at corresponding end sections of the large-diameter section 531. The base section 511 of the retaining element 51 is formed with a fitting hole 511c into which the small-diameter section 532 on the vehicle interior side of the pair of small-diameter sections 532 and 533 of each of the support shaft elements 53 is fitted. The small-diameter section 533 on the vehicle exterior side is fitted into a fitting hole 521a of the connecting element 52, which is described next.

[0029] The connecting element 52 integrally comprises a disc-shaped cover section 521, which closes the openings of the plurality of retaining sections 50 on the outside of the vehicle and prevents the plurality of planetary gears 4 from falling out; a wedge-shaped shaft section 522, which extends from a central section of the cover section 521 to the outside of the vehicle; and an externally threaded section 523, which is provided at its end section on the outside of the vehicle. A recessed section 520, which is recessed axially towards the outside of the vehicle, is formed in the central section of the cover section 521. As can be seen from the Fig. As can be seen in Figure 2, the recessed section 520 accommodates the bearing 83, which supports the shaft section 222 of the reduction gear 22.

[0030] The cover section 521 is formed with a plurality of locating holes 521a into which the small-diameter sections 533 on the vehicle exterior of the support shaft elements 53 are fitted, and with a plurality of screw holes 521b into which the externally threaded sections 543 of the screws 54 are screwed, the screws being arranged alternately along the circumferential direction of the cover section 521. Distal end surfaces 513b of the leg shaft sections 513 bear against the cover part 521 of the connecting element 52 under the axial force of the screws 54. A plurality of axially extending splined teeth 522a are formed on an outer circumference of the splined shaft section 522. The splined shaft section 522 is inserted into the central section of the inner element 6.

[0031] As from the Fig. As can be seen in Figure 3, the planet gear 4 is supported by the bearing 84 on an outer side of the large-diameter section 531 of the support shaft element 53. The bearing 84 is a needle roller bearing and has a plurality of needle rollers 841 and a cage 842 that holds the plurality of needle rollers 841. In the present embodiment, two bearings 84 are arranged axially side by side between the large-diameter section 531 of the support shaft element 53 and the planet gear 4.

[0032] The outer element 7 extends around an outer circumference of the planetary gear mechanism 12. An internally toothed gear 73, which meshes with the plurality of planet gears 4, is provided on an inner section of the outer element 7. The configuration of the outer element 7 will be described in detail later.

[0033] The inner element 6 consists of a hub ring 61, in the central section of which a fitting section 60 is formed, into which the splined shaft section 522 of the connecting element 52 is fitted, and of an inner ring 62, which is fitted to an end section on the vehicle's inner side of the hub ring 61. A nut 873 is screwed onto the externally threaded section 523 of the connecting element 52, which projects from the fitting section 60 towards the vehicle's outer side. The carrier 5 is connected to the inner element 6 in such a way that it cannot rotate relative to it, since the section 522 of the connecting element 52 is fitted into the hole 60 via a keyway.

[0034] The inner ring 62 is prevented from falling off the hub ring 61 by the cover section 521 of the connecting element 52. It should be noted that the end section of the hub ring 61 may be crimped on the inside of the vehicle to prevent the inner ring 62 from detaching.

[0035] The multitude of rolling elements 80 is arranged between the inner element 6 and the outer element 7 to form two rows of rolling elements. Specifically, the multitude of rolling elements 80 forms a first row 80A on the side of the wheel-tire assembly 91 and a second row 80B on the side of the planetary gear mechanism 12. The multitude of rolling elements 80 of the first row 80A is held in a first cage 801 and rolls on a first inner raceway surface 61a formed in the hub ring 61. The multitude of rolling elements 80 of the second row 80B is held in a second cage 802 and rolls on a second inner raceway surface 62a formed in the inner ring 62. In the present embodiment, the rolling elements 80 are spherical, but this is not limiting, and the rolling elements 80 can also be chamfered rollers.

[0036] The inner element 6 has a hub flange 601, to which the wheel 911 of the wheel-tire assembly 91 is attached, and a cylindrical hub section 602, which is located on the inside of the first row of rolling elements 80A and the second row of rolling elements 80B. The hub flange 601 is part of the hub ring 61. The cylindrical hub section 602 is formed from a portion of the hub ring 61 and the inner ring 62. The first inner raceway surface 61a and the second inner raceway surface 62a are formed on an outer circumference of the cylindrical hub section 602.

[0037] A hub bolt 95 for attaching a brake disc 93 and the wheel 911 of the wheel-tire assembly 91 is fastened to the hub flange 601. The hub bolt 95 is pressed axially into a hole 601a formed in the hub flange 601, and a Fig. The visible hub nut 96 is screwed onto a distal end section thereof. It should be noted that alternatively, a threaded hole may be formed in the hub flange 601, into which the hub screw is screwed.

[0038] The outer element 7 has a cylindrical section 71 that fits into the mounting hole 920 of the fastening element 92, a flanged section 72 that is attached to an open end face 920a of the mounting hole 920 in the fastening element 92, and the internally toothed gear element 73 that is provided inside the cylindrical section 71. In the present embodiment, the cylindrical section 71, the flanged section 72, and the internally toothed gear element 73 are formed in one piece.

[0039] The cylindrical section 71 has an outer diameter that is slightly smaller than the diameter of the mounting hole 920 and is inserted into the mounting hole 920 from the outside of the vehicle to the inside. A sealing element 881 is arranged between an end section of the cylindrical section 71 on the outside of the vehicle and the hub ring 61. The cylindrical section 71 is formed with a first outer raceway surface 71a, on which the plurality of rolling elements 80 of the first row 80A rolls, and a second outer raceway surface 71b, on which the plurality of rolling elements 80 of the second row 80B rolls.

[0040] The present embodiment, as it is derived from the Fig. As can be seen in Figure 6, section 72 is constructed from a plurality of flange pieces 721. The plurality of flange pieces 721 are arranged radially so that they project outwards from the cylindrical section 71. However, the flange section 72 can also be arranged annularly on an outer circumferential side of the cylindrical section 71. The mounting element 92 has threaded holes 92b, which are configured to open onto an open end face 920a, into which screws 97 are screwed to fasten the flange section 72. The opening end face 920a is an end face of the mounting element 92 on the outside of the vehicle around an opening of the mounting hole 920. Each of the flange pieces 721 has a hole for inserting the screw 72a, which is formed in a position corresponding to the screw hole 92b.The outer element 7 is attached to the fastening element 92 by inserting the screws 97 into the bolt insertion holes 72a and screwing them into the screw holes 92b.

[0041] As from the Fig. As can be seen in Figure 7, the internally toothed gear 73 is formed with a plurality of helical gears 73a, the tooth flank lines of which are inclined with respect to the axial direction. The internally toothed gear 73 is in mesh with the helical gears 4a of the plurality of planetary gears 4. A bearing fitting 711 is formed on an inner section of the cylindrical section 71, into which the bearing 85 is fitted.

[0042] Bearing 85 is a ball bearing and, as can be seen from the Fig. Figure 3 shows an outer ring 851, an inner ring 852, and a plurality of rolling elements 853 arranged between the outer ring 851 and the inner ring 852. The outer ring 851 is held by the fitting section 711 of the outer element 7. The inner ring 852 is arranged on an outer circumference of the base section 511 of the retaining element 51, and a side surface of it on the outside of the vehicle faces the flange section 512 of the retaining element 51. (Lubricating structure of the drive device 1)

[0043] Next, a lubrication structure for lubricating each component of the drive device 1 with lubricating oil 90 is described. The reduction gear mechanism 11, the planetary gear mechanism 12, and the hub assembly 13 of the drive device 1 are lubricated by the lubricating oil 90, which is enclosed in a space surrounded by the housing 3, the outer element 7, and the fastening element 92.

[0044] Fig. Figure 8A is a schematic configuration representation showing a surface of the housing 3 on the side of the fastening element 92. Fig. Figure 8B is a cross-sectional view of housing 3, cut along line AA in Fig. 8A. Fig. Figure 9 is a perspective view of housing 3. Fig. 8A and Fig. 8B are the shapes of holes and the like formed inside the housing 3, shown by dashed lines, and in Fig. 8B is part of the reduction gear 22 22, which is combined with the housing 3, represented by a long dashed double short dashed line. Fig. Figure 9 shows the housing 3 together with a shielding plate 891, which is to be mounted on the housing 3.

[0045] The housing 3 has an outer wall section 31 that surrounds the pinion 21 and the large-diameter section 221, as well as the disc section 223 of the reduction gear 22, and a plurality of mounting pieces 32 that project from the outer wall section 31. A flat surface of the outer wall section 31 on the outside of the vehicle serves as a bearing surface 31a, which rests against the mounting element 92. A bolt insertion hole 320 is formed in each of the mounting pieces 32, into which the screw 871 is inserted to mount the housing 3 to the mounting element 92.

[0046] Part of the housing 3 is located within the large-diameter gear section 221 of the reduction gear 22. This part of the housing 3 is hereinafter referred to as the projecting section 33. The projecting section 33 is disk-shaped and centered on the axis of rotation O. 22The reduction gear 22 is arranged and designed such that it projects further on the outside of the vehicle than a counter surface 3a of the housing 3, which faces an end face 221b of the large-diameter gear section 221 on the inside of the vehicle. The counter surface 3a is a flat surface that faces the outside of the vehicle and is perpendicular to the axial direction. An end face 33a of the projecting section 33 on the outside of the vehicle and the disc section 223 of the reduction gear 22 are axially spaced a short distance apart from each other.

[0047] In the following, a section of the housing 3 that is closer to the inside of the vehicle than the opposing surface 3a is referred to as the base section 34. The base section 34 has a housing hole 340 formed therein, in which the output shaft 101 and the bearing 81 of the motor 10 are received together with a part of the pinion gear 21. As can be seen from the Fig. As can be seen in Figure 2, a sealing element 882 is arranged in the housing hole 340 to prevent the lubricating oil 90 from escaping. The pinion 21 is vertically aligned with the axis of rotation O. 22 of the reduction gear 22 is arranged downwards, and an engagement section between the small diameter element 21a of the pinion 21 and the large diameter element 221a of the large diameter section 221 is located in an oil bath of the lubricating oil 90.

[0048] As from the Fig. As can be seen in Figure 2, the bearing 86 is arranged between the large-diameter part 221 and the projecting part 33 to rotatably support the reduction gear 22 relative to the housing 3. The bearing 86 has an outer ring 861, an inner ring 862, and a plurality of rolling elements 863 arranged between the outer ring 861 and the inner ring 862. The outer ring 861 is fitted to the inside of the large-diameter gear section 221. The projecting section 33 is fitted inside the inner ring 862.

[0049] Fig. Figure 10A is a configuration representation showing a surface of the reduction gear 22 on the housing side 3. Fig. Figure 10B is a cross-sectional view of the reduction gear 22 22, in which a cross-section of the shaft section 222 of the reduction gear 22 is viewed from the outside of the vehicle to the inside of the vehicle.

[0050] The disc section 223 of the reduction gear 22 is provided with a plurality of through holes 223a through which the lubricating oil 90 flows in the axial direction. In the present embodiment, three through holes 223a are formed at equal intervals in the circumferential direction. An oil hole 201 for supplying lubricating oil 90 to the outside of the vehicle, relative to the disc section 223, is located in the shaft section 222 of the reduction gear 22 along the axis of rotation O. 22 Furthermore, a multitude of outlet holes 202, which are connected to the oil well 201, are formed in the shaft section 222. The outlet holes 202 extend radially along the shaft section 222 and open into an outer surface 222b of the shaft section 222.

[0051] In the present embodiment, two holes 202 are formed in the shaft section 222. According to the present embodiment, each of the holes 202 opens into the outer circumferential surface 222b of the shaft section 222, which is located further on the outside of the vehicle than the sun gear element 222a. However, this is not a limitation, and one, three, or more holes 202 can also be formed in the section of the shaft 222. The holes 202 can, for example, extend to a base surface of the sun gear element 222a.

[0052] When the reduction gear 22 rotates, the lubricating oil 90 is discharged to the outside from the outlet holes 202 by centrifugal force. The lubricating oil 90 exiting the outlet holes 202 lubricates each component of the planetary gear mechanism 12 and the hub unit 13. In particular, the lubricating oil 90 is supplied to the meshing sections between the planet gears 4 and the shaft section 222 of the reduction gear 22 and the internally toothed gear element 73 of the outer element 7, as well as to the bearings 83 and 84 and the plurality of rolling elements 80.

[0053] However, a sealing element can, for example, be arranged between section 521 of the cover of the connecting element 52 and the cylindrical section 71 of the outer element 7, so that only the planetary gear mechanism 12 is lubricated by the lubricating oil 90 exiting the drain holes 202. In this case, it is advantageous, for example, to apply a grease with a higher viscosity than the lubricating oil 90 between the cylindrical section 602 of the hub and the cylindrical section 71 of the outer element 7. That is, it is sufficient that the lubricating oil 90 exiting the drain holes 202 is supplied at least to the planetary gear mechanism 12.

[0054] The housing 3 is equipped with a storage reservoir 301 for storing the lubricating oil 90, a vent chamber 302 which is connected to the outside air, a vent passage 303 which connects the storage reservoir 301 to the vent chamber 302, an outside air connection hole 304 which connects the vent chamber 302 to the outside air, a collection unit 305 which collects the lubricating oil 90 taken up by the rotation of the reduction gear 22, and an oil passage 306 which supplies the lubricating oil 90 collected by the collection unit 305 to the oil hole 201 of the reduction gear 22.

[0055] By forming the storage container 301 in the housing 3, the quantity of lubricating oil 90 inside the drive device 1 can be increased, thereby suppressing deterioration of the lubricating oil 90 even after prolonged use, and furthermore, fluctuations in the level of the oil emanating from the Fig. The visible oil level 90a is suppressed, even when the lubricating oil 90 is drawn upwards by the rotation of the reduction gear 22. Furthermore, the storage container 301 is connected to the vent chamber 302, and accordingly, when the temperature inside the housing 3 and the outer element 7 in the drive device 1 rises, expanded air is released through the vent chamber 302 and the through-hole 304 to the outside of the housing 3, thus preventing a decrease in the sealing capacity of the sealing elements 881 and 882 due to an increase in internal pressure.

[0056] The storage reservoir 301 is located closer to the motor 10 in the axial direction of the drive device 1 than the section 223 of the reduction gear 22 and is open in the direction of the section 223. The plurality of through-holes 223a of the section 223 are formed at positions where at least parts of them are aligned axially with and in contact with the storage reservoir 301 when the reduction gear 22 rotates. This configuration allows the lubricating oil 90 to flow between the section of the disc section 223 that is closer to the outside of the vehicle and the storage reservoir 301, via the plurality of through-holes 223a of the disc section 223.

[0057] As from the Fig. As can be seen in 8A, the storage tank 301 is located off the axis of rotation O. 22 of the reduction gear 22 is formed downwards and, viewed from the outside of the vehicle, extends along the axis of rotation O22 a partially circular shape. An inner surface of the storage container 301 consists of an arcuate surface 301a, which is arcuate in the axial direction and whose center is the axis of rotation O. 22 The surface 301b is formed by a flat surface 301b, which is linear in the axial direction and connects both end sections of the arcuate surface 301a, and a base surface 301c, which is perpendicular to the axial direction. The flat surface 301b is a planar surface that is horizontal.

[0058] Part of the storage container 301 is formed in the hub section 33, and another part of it in the base section 34. That is, in the present embodiment, the storage container 301 extends over both the hub section 33 and the base section 34. However, the storage container 301 can also be formed only in the section with the projection 33.

[0059] The ventilation chamber 302 extends upwards from the storage container 301. Viewed from the outside of the vehicle, the ventilation chamber 302 has a rotation axis O. 22 a circular shape. In the present embodiment, the venting chamber 302 is oriented from the axis of rotation O. 22 The reduction gear 22 extends upwards, and the storage tank 301 and the ventilation chamber 302 are connected to each other via two passages 303. As in Fig. As can be seen in Figure 8B, the ventilation passages 303 are inclined with respect to an upward / downward direction. This allows the passages 303 to be formed by inserting a cutting tool, such as a drill or similar, through an opening in the storage container 301 during the manufacture of the housing 3.

[0060] The outside air connection hole 304 is located further upstream of the ventilation chamber 302. In the present embodiment, the outside air connection hole 304 is configured such that it extends vertically from an upper end section of the ventilation chamber 302 and is open towards the outer circumferential surface 31b of the outer wall section 31 of the housing 3. As shown in Fig. As can be seen in Figure 2, the outside air connection hole 304 accommodates a filter 892 which is breathable and has waterproof properties.

[0061] The vent chamber 302 is parallel to the axis of rotation O in one direction. 22The reduction gear 22 is recessed from the end surface 33a of the projecting section 33, which is the opposing surface facing the disc section 223 of the housing 3. An opening on section 223 of the vent chamber 302 is partially shielded by the shielding plate 891, which prevents splash lubricating oil 90 from splashing directly onto the outside air connection hole 304 and also prevents large bubbles from entering the vent chamber 302. As can be seen from the Fig. As can be seen in Figure 9, the projection 33 is formed with a stepped recess 311 around the opening of the ventilation chamber 302, and the shielding plate 891 is fitted into this stepped recess 311. The stepped recess 311 and the shielding plate 891 have, along the axis of rotation O 22Viewed, it has a rounded rectangular shape. The shielding plate 891 can be attached to the housing 3 by fitting it into the stepped recessed section 311 or, for example, by welding, crimping, or screwing it to the housing 3.

[0062] The collecting unit 305 is a recessed part formed by cutting out a portion of the outer wall section 31, such that it opens along the direction of rotation of the reduction gear 22. In the present embodiment, two collecting units 305 are formed in the housing 3 to efficiently collect the lubricating oil 90 collected by the rotation of the reduction gear 22, both in the forward direction (the direction of rotation of the reduction gear 22 when the vehicle moves forward) and in the reverse direction (the direction of rotation of the reduction gear 22 when the vehicle moves backward).

[0063] As can be seen from Figures 8A and 9, an inner surface of the outer wall section 31 has an arcuate inner surface 31c which is on the axis of rotation O 22 The reduction gear 22 is centered on a first inclined surface 31d extending from one end section of the arcuate inner surface 31c towards one of the collecting units 305 and continuing to an inner surface 305a of that collecting unit 305. A second inclined surface 31e extending from the other end section of the arcuate inner surface 31c towards the other collecting unit 305 and continuing to an inner surface 305a of the other collecting unit 305 is also formed. The arcuate inner surface 31c faces upwards from the pair of collecting units 305. The first and second inclined surfaces 31d and 31e are inclined downwards, as they extend towards the collecting units 305.

[0064] When the reduction gear 22 rotates, the large-diameter gear section 221 scoops up the lubricating oil 90, and the scooped-up lubricating oil 90 adheres to the arcuate inner surface 31c and the first and second inclined surfaces 31d and 31e, and the adhering lubricating oil 90 flows down the first and second inclined surfaces 31d and 31e and into one or the other of the pair of collecting devices 305. This collects the lubricating oil 90 in the collecting containers 305.

[0065] The lubricating oil 90 collected in the collecting units 305 is supplied to the bore 201 of the reduction gear 22 via the oil passage 306. The oil passage 306 consists of an axial bore 306a, which is aligned axially with the oil bore 201 of the reduction gear 22 along the axis of rotation O22 of the reduction gear 22, and a pair of radial bores 306b, each communicating between the axial bore 306a and the pair of collecting units 305.

[0066] The axial directional hole 306a faces the oil bore 201 of the reduction gear 22 at an end section on the outside of the vehicle and is connected to the pair of radial directional holes 306b at an end section on the inside of the vehicle. The pair of holes 306b in the radial direction is formed from the outer circumferential surface 31b of the section of the outer wall 31 in the direction of the hole 306a in the axial direction. As shown in Fig. As can be seen in Figure 9, the end section of the hole 306a is closed in the axial direction on the outer surface 31b of the outer wall section 31 by a plug 893.

[0067] The lubricating oil 90 supplied to the oil hole 201 of the reduction gear 22 is drained from the drain holes 202, as described above, to lubricate each component of the planetary gear mechanism 12. For example, it flows downwards between the support 5 and the cylindrical section 71 of the outer element 7 and is drawn back up by the rotation of the reduction gear 22. By circulating the lubricating oil 90 in this way, the sliding between the individual elements becomes more uniform, and heat generation at the meshing sections is also suppressed. (Effects of the embodiment)

[0068] According to the present embodiment described above, the reservoir 301 is formed in the hub section 33, which is part of the housing 3 located inside the gear section 221 of the large-diameter reduction gear 22. This allows the amount of lubricating oil 90 in the drive device 1 to be increased while simultaneously preventing the housing 3 from becoming larger. That is, by effectively utilizing the dead space inside the large-diameter gear section 221 as part of the reservoir 301, the drive device 1 can be made smaller and lighter.

[0069] The present embodiment also provides that the venting chamber 302 extends upwards from the storage container 301. This prevents foreign bodies from contaminating the lubricating oil 90, while simultaneously preventing a pressure increase inside the housing 3 and the outer element 7.

[0070] Furthermore, according to the present embodiment, the collecting devices 305 and the oil passage 306 are formed in the housing 3, and accordingly, the lubricating oil 90 taken up by the rotation of the reduction gear 22 can be efficiently supplied to the planetary gear mechanism 12. (Modification)

[0071] Next, a modification of the drive device will be presented with reference to the Fig. 11 described. In this modification, the shapes of the housing 3 and the reduction gear 22 differ from those of the embodiment described above, and the remaining configuration is the same as that of the embodiment described above. Fig. Figure 11 shows the housing 3, the reduction gear 11, and the motor 10 according to the modification, while other parts are not shown. Furthermore, in Fig. 11 the elements which are identical to those in the above embodiment, with the same reference numerals as in Fig. 2 is designated.

[0072] In the present embodiment, a case was described in which the outer ring 861 of the bearing 86 is fitted into the large-diameter gear section 221 and rotates together with the reduction gear 22, and the section 33 with the projection is fitted into the inner ring 862 of the bearing 86. In the present embodiment, however, the outer ring 861 of the bearing 86 is attached to the section 33 with the projection, and the inner ring 862 of the bearing 86 is configured to rotate together with the reduction gear 22.

[0073] The reduction gear 22 comprises, in one piece, the large-diameter gear section 221, the shaft section 222, the disc section 223, and an annular projection 224, which is fitted to the inside of the inner ring 862. The annular projection 224 extends axially from a mating surface 223b of the disc section 223, which faces the hub section 33, towards the inside of the vehicle.

[0074] The hub section 33 of the housing 3 is formed with a recessed section 330, which is annular and centered on the axis of rotation O22 of the reduction gear 22. The recessed section 330 accommodates the bearing 86 and the annular projection 224 of the reduction gear 22. The outer ring 861 is fitted to an inner circumferential surface 330a on an outer diameter side of the recessed section 330. A clearance is formed between an outer circumferential surface 330b on a bore diameter side of the recessed section 330 and the annular projection 224.

[0075] This modification also provides the same effects as the embodiment described above. (Additional information)

[0076] Although the present invention has been described above in accordance with the embodiment and modifications, the embodiment and modifications are not intended to limit the invention according to the claims. It should also be noted that not all combinations of features described in the embodiment and modifications are necessarily essential for solving the problem according to the invention.

[0077] The present invention can also be implemented with modifications by omitting, adding, or replacing some of the components without departing from the spirit and scope of the invention. For example, in the embodiment described above, a housing is described in which section 222 of the reduction gear 22, which forms the reduction gear 11, projects from the housing 3 and is received in the outer element 7. However, this is not limiting, and the entire reduction gear 22 can be housed within the housing 3. That is to say, it is sufficient if the housing 3 receives at least part of the reduction gear 11. Reference symbol list 1 DRIVE DEVICE 10 MOTOR 11 REDUCTION GEAR 12 PLANETARY GEAR MECHANISM 201 OIL HOLE 202 OUTLET HOLE 21-pinion (input gear) 22 REDUCTION GEAR (DRIVE GEAR) 221 Large diameter gear section 222 WAVE SECTION 223 DISC SECTION 223a THROUGH HOLE 3 HOUSINGS 301 STORAGE CONTAINERS 302 VENTILATION CHAMBER 303 VENTILATION PASSAGE 305 COLLECTION DEVICE 306 OIL TRANSIT 33 Hub Section (Part of Housing 3) 4 PLANETARY WHEEL 86 STORAGE 90 Lubricating Oil 891 Shielding plate QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 2015 - 132 315 A

[0004]

Claims

Vehicle drive device for driving a wheel-tire assembly of a vehicle, comprising: a motor; an oil-lubricated reduction gear mechanism;and a housing that accommodates at least part of the reduction gear mechanism, the reduction gear mechanism having an input gear and an output gear, the output gear having a large-diameter gear section having a cylindrical shape with a diameter larger than the diameter of the input gear, a shaft section having an outside diameter smaller than the outside diameter of the large-diameter gear section, and a disk section provided between the large-diameter gear section and the shaft section, the input gear meshing with the large-diameter gear section, a part of the housing being arranged on an inside side of the large-diameter gear section, and a reservoir for storing the lubricating oil being provided in that part of the housing. Vehicle drive device according to claim 1, wherein an axis of rotation of the input wheel and an axis of rotation of the output wheel are parallel to each other, wherein the storage container is provided in an axial direction parallel to the axis of rotation of the output wheel closer to the motor side than the disc section, and wherein the storage container is open towards the disc section. Vehicle drive device according to claim 2, wherein the disc section has a plurality of through holes through which the lubricating oil is caused to flow in the axial direction. Vehicle drive device according to claim 1, wherein a bearing which rotatably supports the output gear with respect to the housing is arranged between the large diameter gear section and the part of the housing. Vehicle drive device according to claim 1, wherein the drive wheel is arranged in a vertical direction below an axis of rotation of the driven wheel and wherein a meshing section between the drive wheel and the large diameter gear section of the driven wheel is located in an oil bath of lubricating oil. Vehicle drive device according to claim 1, wherein an oil hole for supplying the lubricating oil to the wheel-tire assembly relative to the disc section is provided in the shaft section along an axis of rotation of the output wheel, and wherein the housing is provided with a collecting unit that collects the lubricating oil scooped up by the rotation of the output wheel, and with an oil passage that supplies the lubricating oil collected by the collecting unit to the oil hole. Vehicle drive device according to claim 6, which further comprises a planetary gear mechanism with a plurality of planet gears, wherein the plurality of planet gears is arranged on an outer circumference of the shaft section, wherein a discharge opening is provided in the shaft section which is connected to the oil hole, and wherein the lubricating oil discharged from the discharge opening is supplied to the planetary gear mechanism. Vehicle drive device according to claim 1, wherein the housing is provided with a vent chamber which is connected to the ambient air and which is provided in a vertical direction above the storage container, and wherein a ventilation passage is also provided which connects the storage container and the vent chamber. Vehicle drive device according to claim 8, wherein the venting chamber is provided such that it is recessed from a counter surface facing the disc section of the housing in a direction parallel to an axis of rotation of the output wheel, and an open end section on the disc section side is closed by a shielding plate.

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