drive device

Abstract

One embodiment of the drive device of the present application includes: a motor having a motor shaft that rotates around a first axis; a power transmission mechanism connected to the motor shaft from one side of the shaft; a housing having a motor housing portion that houses the motor inside and a gear housing portion that houses the power transmission mechanism inside; and a fluid path that is at least partially disposed inside the housing. The power transmission mechanism has a hollow shaft that is hollow and that is centered on a second axis that is parallel to the first axis. The fluid path has: a hollow shaft internal flow path portion that is provided in the hollow shaft; a supply portion that is provided on an upper side of the motor; and a relay flow path portion that connects the hollow shaft internal flow path portion and the supply portion.

Description

Technical Field

[0001] This invention relates to a driving device. Background Technology

[0002] In recent years, with the popularization of electric and hybrid vehicles, the development of drive systems for driving vehicles has been progressing. These drive systems internally store fluids such as oil to lubricate gear surfaces or cool rotating motors. Patent Document 1 discloses a structure that uses a pump to draw oil stored at the bottom of a housing upwards and direct it to a cooling pipe passing above the electric motor, supplying the oil to the electric motor from the outlet of the cooling pipe.

[0003] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 2020-178520 Summary of the Invention

[0004] The technical problem that the invention aims to solve In drive devices with fluid paths that circulate fluid, if the flow path is long, the pipeline resistance of the fluid path increases, which can lead to problems such as larger pumps for pressurizing fluid or increased power consumption of the pumps.

[0005] In view of the above problems, one objective of the present invention is to provide a drive device that can shorten the fluid path that enables fluid flow and suppress the pipe resistance of the fluid path.

[0006] Technical solutions adopted to solve technical problems One embodiment of the drive device of the present invention comprises: a motor having a motor shaft rotating about a first axis; a power transmission mechanism connected to the motor shaft from one axial side; a housing having a motor housing portion and a gear housing portion, the motor housing portion housing the motor internally, and the gear housing portion housing the power transmission mechanism internally; and a fluid path, at least a portion of which is disposed within the housing. The power transmission mechanism has a hollow shaft centered on a second axis parallel to the first axis. The fluid path comprises: a hollow shaft inner flow path portion disposed within the hollow shaft; a supply portion disposed above the motor; and a relay flow path portion connecting the hollow shaft inner flow path portion to the supply portion.

[0007] Invention Effects According to one aspect of the present invention, a drive device is provided that can shorten the fluid path for fluid flow and suppress pipeline resistance. Attached Figure Description

[0008] Figure 1 This is a schematic diagram of the drive device according to the first embodiment. Figure 2 This is a schematic diagram of the drive device according to the second embodiment. Figure 3 This is a schematic diagram of the drive device according to the third embodiment. (Symbol Explanation) 1, 101, 201 Drive unit; 2 Motor; 3 Power transmission mechanism; 6 Housing; 6b Partition wall; 6c Motor cover wall; 8 Pump; 21 Motor shaft; 41 Gear; 45 Hollow shaft; 81 Motor housing; 82 Gear housing; 90, 190, 290 Fluid paths; 91 Hollow shaft internal flow path; 92 Supply pipe (supply section); 94 Relay flow path; 95, 195, 295 First flow path; 96 Motor shaft internal flow path; 97 Second flow path; 192 Supply tank (supply section); 193 Collection container (storage section); 198 Path; J1 First axis; J2 Second axis; O Fluid; P Storage section; S1, S2 Flow path cross-sectional area Detailed Implementation

[0009] Hereinafter, the driving device according to an embodiment of the present invention will be described with reference to the accompanying drawings. In the following description, the vertical direction is defined based on the positional relationship of the drive unit of the embodiments shown in the figures when it is installed on a vehicle located on a horizontal road surface. Furthermore, in the figures, an XYZ coordinate system is appropriately shown as a three-dimensional rectangular coordinate system. In the XYZ coordinate system, the Z-axis direction is the vertical direction. The +Z side is the upper vertical direction, and the -Z side is the lower vertical direction. In the following description, the upper vertical direction is simply referred to as the "upper side," and the lower vertical direction is simply referred to as the "lower side." The X-axis direction is the direction orthogonal to the Z-axis direction, and it is the forward-backward direction of the vehicle on which the drive unit is installed. In the following embodiments, the +X side is the front side of the vehicle, and the -X side is the rear side of the vehicle. The Y-axis direction is the direction orthogonal to both the X-axis and Z-axis directions, and it is the left-right direction of the vehicle, i.e., the vehicle width direction. In the following embodiments, the +Y side is the left side of the vehicle, and the -Y side is the right side of the vehicle. The forward-backward and left-right directions are horizontal directions orthogonal to the vertical direction.

[0010] The first axis J1, as appropriately shown in the figures, extends along the Y-axis direction, i.e., the left-right direction of the vehicle. In the following description, unless otherwise specified, the direction parallel to the first axis J1 will be simply referred to as the "axial direction," and the radial direction centered on the first axis J1 will be simply referred to as the "radial direction." Furthermore, in the following description, the +Y side will sometimes be simply referred to as one side of the axial direction, and the -Y side will sometimes be simply referred to as the other side of the axial direction.

[0011] <First Implementation> Figure 1This is a schematic diagram of the drive device 1 according to the first embodiment. The drive unit 1 is installed in vehicles that use a motor as a power source, such as hybrid electric vehicles (HEV), plug-in hybrid electric vehicles (PHV), and electric vehicles (EV), and is used as their power source.

[0012] The drive unit 1 includes: a motor 2; a power transmission mechanism 3; a housing 6; a fluid O housed inside the housing 6; a fluid path 90 for the fluid O to flow through; a pump 8; and multiple bearings 83, 84, 85, 86, 87, 88, and 89.

[0013] (shell) The housing 6 has a motor housing 81 and a gear housing 82. The motor housing 81 houses the motor 2, and the gear housing 82 houses the power transmission mechanism 3. Furthermore, the housing 6 has a partition wall 6b that divides the internal spaces of the motor housing 81 and the gear housing 82. The gear housing 82 is located on one axial side (+Y side) of the motor housing 81.

[0014] A supply through hole 6s, a shaft through hole 6p, and a partition wall opening 6q are provided at the partition wall 6b. The supply through hole 6s, the shaft through hole 6p, and the partition wall opening 6q enable the internal spaces of the motor housing 81 and the gear housing 82 to communicate with each other.

[0015] The motor housing 81 has a motor peripheral wall portion 6g and a motor housing portion 6c. The motor peripheral wall portion 6g is cylindrical, extending axially around a first axis J1. The motor peripheral wall portion 6g surrounds the motor 2 radially outward from the first axis J1. The opening on one axial side (+Y side) of the motor peripheral wall portion 6g is covered by a partition wall 6b, and the opening on the other axial side (-Y side) is covered by the motor housing portion 6c. The motor housing portion 6c extends along a plane orthogonal to the first axis J1. The motor housing portion 6c covers the motor 2 from the other axial side (-Y side).

[0016] The gear housing 82 has a gear peripheral wall portion 6f and a gear cover wall portion 6a. The gear peripheral wall portion 6f is cylindrical and extends axially. The gear peripheral wall portion 6f surrounds each gear 41, 42, 43, and 51 of the power transmission mechanism 3 radially outward from the first axis J1, the second axis J2, and the third axis J3 described below. The opening on the other axial side (-Y side) of the gear peripheral wall portion 6f is covered by a partition wall 6b, and the opening on one axial side (+Y side) is covered by the gear cover wall portion 6a. The gear cover wall portion 6a extends along a plane orthogonal to the first axis J1. The gear cover wall portion 6a covers the power transmission mechanism 3 from one axial side (+Y side).

[0017] Fluid O is housed inside the housing 6. Fluid O circulates within the fluid path 90, described later. In this embodiment, fluid O is oil, used not only for cooling motor 2 but also for lubricating power transmission mechanism 3. To fulfill the functions of both lubricating and cooling oil, fluid O is preferably an oil with a low viscosity, similar to automatic transmission fluid (ATF).

[0018] A storage section P for accumulating fluid O is provided in the lower region of the gear housing 82. The fluid O accumulated in the storage section P is lifted and diffused into the gear housing 82 by the operation of the power transmission mechanism 3. The fluid O diffused into the gear housing 82 covers the tooth surfaces of the power transmission mechanism 3, serving as lubrication for the power transmission mechanism 3. In addition, the fluid O in the storage section P is supplied to the motor 2 through the fluid path 90.

[0019] (motor) In this embodiment, motor 2 is an internal rotor type motor. Furthermore, motor 2 in this embodiment is, for example, a three-phase AC motor. Motor 2 functions as both an electric motor and a generator. Motor 2 includes a motor shaft 21, a rotor 20, and a stator 25.

[0020] The motor shaft 21 extends axially around the first axis J1. The motor shaft 21 rotates around the first axis J1. The motor shaft 21 is hollow. A hollow portion 22 extending axially and open at both ends is provided at the motor shaft 21.

[0021] The motor shaft 21 has a hollow first shaft portion 21A and a second shaft portion 21B. The first shaft portion 21A and the second shaft portion 21B are arranged coaxially. The first shaft portion 21A and the second shaft portion 21B are connected to each other and rotate synchronously about a first axis J1.

[0022] The first shaft portion 21A is disposed inside the motor housing portion 81. The rotor 20 is fixed to the outer peripheral surface of the first shaft portion 21A. The second shaft portion 21B is disposed inside the gear housing portion 82. The power transmission mechanism 3 is connected to the second shaft portion 21B.

[0023] The motor shaft 21 extends across the motor housing 81 and gear housing 82 of the housing 6. The motor shaft 21 passes through the shaft passage hole 6p of the partition wall 6b. A connecting portion between the first shaft portion 21A and the second shaft portion 21B is disposed inside the shaft passage hole 6p.

[0024] The rotor 20 is rotatable about the first axis J1. The rotor 20 has a rotor core and a rotor magnet fixed to the rotor core. The torque of the rotor 20 is transmitted to the power transmission mechanism 3.

[0025] The stator 25 surrounds the rotor 20 radially outward. The stator 25 has a stator core, coils mounted in the stator core, and an insulator (not shown) between the stator core and the coils. The stator 25 is held in the housing 6. The stator core has multiple pole teeth (not shown) extending radially inward from the inner circumferential surface of the annular yoke. Coil wires are arranged between the pole teeth. The coil wires located in the gaps between adjacent pole teeth constitute the coils. The insulator is made of an insulating material.

[0026] (Power transmission mechanism) The power transmission mechanism 3 transmits the power of the motor 2 to the output shaft 55 through multiple gears 41, 42, 43, and 51. The power transmission mechanism 3 is connected to the motor shaft 21 from one axial side (+Y side). The power transmission mechanism 3 has a reduction gear 4 and a differential gear 5.

[0027] The reduction gear 4 has the function of reducing the rotational speed of the motor 2 and increasing the torque output from the motor 2 according to the reduction ratio. The reduction gear 4 transmits the torque output from the motor 2 to the differential gear 5.

[0028] The reduction gear 4 includes a pinion 41, a hollow shaft 45, and a counterspindle gear 42 and a drive gear 43 fixed to the hollow shaft 45. That is, the power transmission mechanism 3 has multiple gears 41, 42, 43, and a hollow shaft 45. The torque output from the motor 2 is transmitted to the gear ring 51 of the differential device 5 via the motor shaft 21 of the motor 2, the pinion 41, the counterspindle gear 42, and the drive gear 43. The gear ratio and number of gears can be varied according to the required reduction ratio.

[0029] The pinion 41 is fixed to the outer circumferential surface of the motor shaft 21 of the motor 2. The pinion 41 and the motor shaft 21 rotate together around the first axis J1.

[0030] The hollow shaft 45 extends along a second axis J2 parallel to the first axis J1. That is, the hollow shaft 45 is centered on the second axis J2. In this embodiment, the second axis J2 is located above the first axis J1. Therefore, the hollow shaft 45 is located above the motor shaft 21. The hollow shaft 45 rotates about the second axis J2. The hollow shaft 45 is hollow. A hollow portion 46 extending axially and open at both ends is provided at the hollow shaft 45.

[0031] The counterspindle gear 42 and the drive gear 43 are arranged axially. The counterspindle gear 42 and the drive gear 43 are disposed on the outer circumferential surface of the hollow shaft 45. The counterspindle gear 42 and the drive gear 43 are connected via the hollow shaft 45. The counterspindle gear 42 and the drive gear 43 rotate about the second axis J2. At least two of the counterspindle gear 42, the drive gear 43, and the hollow shaft 45 can be constructed from a single component. The counterspindle gear 42 meshes with the pinion 41. The drive gear 43 meshes with the gear ring 51 of the differential device 5.

[0032] The differential device 5 is a device used to transmit the torque output from the motor 2 to the wheels of the vehicle. The differential device 5 has the following functions: absorbing the speed difference between the left and right wheels when the vehicle is turning, while transmitting the same torque to a pair of output shafts 55.

[0033] The differential device 5 has a gear ring (lifting gear) 51. The gear ring 51 rotates around a third axis J3 that is parallel to the first axis J1. The torque output from the motor 2 is transmitted to the gear ring 51 via the reduction gear 4.

[0034] A pair of output shafts 55 extend axially. One end of each output shaft 55 is connected to a side gear, and the other end is connected to a wheel. The pair of output shafts 55 transmit the torque of the motor 2 to the road surface via the wheels.

[0035] In this embodiment, the gear ring 51 has a larger diameter compared to the other gears. Furthermore, at least a portion of the gear ring 51 is immersed in the storage section P. Therefore, the power transmission mechanism 3, during actuation, raises the fluid O in the storage section P within the gear ring 51.

[0036] (Bearing) Multiple bearings 83, 84, 85, 86, 87, 88, and 89 are held in the housing 6, respectively supporting any one of the motor shaft 21, hollow shaft 45, and output shaft 55 so that they can rotate.

[0037] Of the bearings 83 and 84 that support the hollow shaft 45, bearing 83 is held in the gear cover wall portion 6a, and bearing 84 is held in the partition wall 6b. Similarly, of the bearings 89 that support the output shaft 55, one is held in the gear cover wall portion 6a, and the other, although not shown in the figure, is held in the partition wall 6b.

[0038] Of the bearings 87 and 88 that support the first shaft portion 21A of the motor shaft 21, bearing 87 is held in the partition wall 6b, and bearing 88 is held in the motor housing wall portion 6c. Of the bearings 85 and 86 that support the second shaft portion 21B of the motor shaft 21, bearing 85 is held in the gear housing wall portion 6a, and bearing 86 is held in the partition wall 6b. Bearings 86 and 87 are disposed inside the shaft passage hole 6p provided in the partition wall 6b.

[0039] The gear housing wall portion 6a has a first bearing retaining portion 61 that holds the bearing 83 and a second bearing retaining portion 62 that holds the bearing 85. Furthermore, the partition wall 6b has a third bearing retaining portion 63 that holds the bearing 84. The motor housing wall portion 6c has a fourth bearing retaining portion 64 that holds the bearing 88. The first bearing retaining portion 61 and the third bearing retaining portion 63 are cylindrical about a second axis J2. The second bearing retaining portion 62 and the fourth bearing retaining portion 64 are cylindrical about a first axis J1. A supply through hole 6s opens inside the third bearing retaining portion 63. That is, the supply through hole 6s of the partition wall 6b opens inside the third bearing retaining portion 63 toward the interior of the gear receiving portion 82.

[0040] (Fluid path) Within the drive unit 1, fluid O circulates in fluid path 90. Fluid path 90 is a path that supplies fluid O from storage unit P to motor 2 and then returns fluid O to storage unit P. At least a portion of fluid path 90 is disposed within housing 6.

[0041] Furthermore, in this specification, "fluid path" refers to the path of fluid O circulating within the housing 6. Therefore, the concept of "fluid path" includes not only the "flow path" that forms a stable flow of fluid that always faces one direction, but also the path that allows fluid to be temporarily retained (e.g., a reservoir), the path for fluid to drip, and the path for fluid to scatter.

[0042] A pump 8 is installed in the fluid path 90. The pump 8 pressurizes the fluid O within the fluid path 90. The pump 8 is fixed to the outer side of the gear housing 82. The pump 8 pressurizes the fluid O in the path of the fluid path 90. The pump 8 can be an electrically driven pump or a mechanical pump that operates in conjunction with the power transmission mechanism 3.

[0043] Furthermore, a cooler for cooling fluid O can be further installed in the fluid path 90. This allows for efficient cooling of the motor 2 via fluid O. The cooler can also be installed in the storage section P to cool the fluid O accumulated in the storage section P.

[0044] The fluid path 90 in this embodiment includes a first flow path 95, a hollow shaft inner flow path 91, a relay flow path 94, a supply pipe (supply section) 92, a second flow path 97, and a motor shaft inner flow path 96.

[0045] The first flow path 95 connects the storage section P to the hollow shaft inner flow path 91 and the motor shaft inner flow path 96. The first flow path 95 guides the fluid O accumulated in the storage section P to the hollow shaft inner flow path 91 and the motor shaft inner flow path 96.

[0046] The first flow path 95 is a hole provided in the gear cover wall portion 6a. That is, the first flow path 95 is disposed inside the gear cover wall portion 6a. The first flow path 95 extends along the wall surface of the gear cover wall portion 6a.

[0047] The first flow path 95 has a main flow path 95c, a first branch path 95a branching from the main flow path 95c, and a second branch path 95b. The main flow path 95c is located in the upstream region of the first flow path 95. The upstream end of the main flow path 95c opens toward the storage section P.

[0048] The first branch path 95a connects the downstream end of the main path 95c to the end of the hollow shaft inner flow path 91. The downstream end of the first branch path 95a opens inside the first bearing retainer 61. The first bearing retainer 61 supports the hollow shaft 45 via the bearing 83. The hollow portion 46 of the hollow shaft 45 opens inside the first bearing retainer 61. Fluid O flows from the first branch path 95a toward the inside of the first bearing retainer 61, and further into the hollow shaft inner flow path 91 of the hollow shaft 45. Furthermore, fluid O is supplied to the bearing 83 as it passes through the inside of the first bearing retainer 61, lubricating the bearing 83.

[0049] The second branch path 95b connects the downstream end of the main path 95c to the end of the internal flow path 96 of the motor shaft. The downstream end of the second branch path 95b opens inside the second bearing retainer 62. The second bearing retainer 62 supports the motor shaft 21 via the bearing 85. The hollow portion 22 of the motor shaft 21 opens inside the second bearing retainer 62. Fluid O flows from the second branch path 95b into the inside of the second bearing retainer 62, and further into the internal flow path 96 of the motor shaft 21. As the fluid O passes through the inside of the second bearing retainer 62, it is supplied to the bearing 85, lubricating the bearing 85.

[0050] In this embodiment, pump 8 is disposed in the main flow path 95c of the first flow path section 95. Pump 8 is installed in the flow path connecting the storage section P to the hollow shaft inner flow path section 91, and supplies fluid O from the storage section P to the hollow shaft inner flow path section 91. Furthermore, pump 8 is installed in the flow path connecting the storage section P to the motor shaft inner flow path section 96, and supplies fluid O from the storage section P to the motor shaft inner flow path section 96. According to the above embodiment, by installing pump 8 in the main flow path 95c located upstream of the first branch path 95a and the second branch path 95b, fluid O can be supplied to the flow paths within both shafts (hollow shaft inner flow path section 91 and motor shaft inner flow path section 96) by a single pump 8.

[0051] A hollow shaft internal flow path 91 is provided in the hollow shaft 45. The hollow shaft internal flow path 91 is a flow path that passes through the hollow section 46 of the hollow shaft 45. The hollow shaft internal flow path 91 guides fluid O from the end of the gear receiving section 82 on one axial side (+Y side) to the end on the other axial side (-Y side).

[0052] The intermediate flow path 94 connects the internal flow path 91 of the hollow shaft to the supply pipe 92. The intermediate flow path 94 is a flow path provided in the supply through hole 6s of the partition wall 6b. Therefore, the intermediate flow path 94 extends in a straight line along the axial direction inside the partition wall 6b.

[0053] The upstream end of the relay flow path 94 opens inside the third bearing retainer 63. The third bearing retainer 63 supports the hollow shaft 45 via the bearing 84. The hollow portion 46 of the hollow shaft 45 opens inside the third bearing retainer 63. Fluid O flows from the hollow shaft inner flow path 91 into the inside of the third bearing retainer 63, and further into the relay flow path 94. As fluid O passes through the inside of the third bearing retainer 63, it is supplied to the bearing 84, lubricating the bearing 84.

[0054] The downstream end of the relay flow path 94 opens toward the upper region within the motor housing 81. Furthermore, the axial (+Y) end of the supply pipe 92 is inserted into the opening at the downstream end of the relay flow path 94. Therefore, the fluid O flowing through the relay flow path 94 flows into the interior of the supply pipe 92 at the downstream end of the relay flow path 94.

[0055] The supply pipe 92 extends axially inside the motor housing 81. The end of the supply pipe 92 on one axial side (+Y side) is supported by the partition wall 6b, and the end on the other axial side (-Y side) is supported by the motor cover wall 6c.

[0056] The supply pipe section 92 is disposed inside the motor housing section 81 on the upper side of the motor 2. The supply pipe section 92 is provided with a spray hole 92h that opens toward the motor 2. Fluid O passing through the supply pipe section 92 is sprayed toward the motor 2 from the spray hole 92h. Thus, the supply pipe section 92 supplies fluid O from outside the motor 2 to the motor 2.

[0057] In this embodiment, the supply pipe 92 is tubular. Therefore, by using the pump 8 to pressurize the fluid O to the supply pipe 92, the pressure of the fluid O in the supply pipe 92 can be increased, and the fluid O can be ejected onto the motor 2. As a result, the fluid O can reach the intricate parts of the motor 2, and the motor 2 can be cooled efficiently.

[0058] The fluid O supplied from the outside to the motor 2 via the supply pipe 92 absorbs heat from the stator 25 as it moves along the surface of the stator 25, thus cooling the stator 25. Furthermore, the fluid O drips from the stator 25 and reaches the lower region within the motor housing 81, and then returns to the storage section P via the partition wall opening 6q.

[0059] The second flow path 97 connects the supply pipe 92 to the flow path 96 inside the motor shaft. The second flow path 97 is a hole provided in the motor housing wall 6c. That is, the second flow path 97 is disposed inside the motor housing wall 6c. The second flow path 97 extends along the wall surface of the motor housing wall 6c.

[0060] The upstream end of the second flow path 97 opens toward the upper region within the motor housing 81. Furthermore, the axial end (-Y side) of the supply pipe 92 is inserted into the opening at the upstream end of the second flow path 97. A portion of the fluid O flowing inside the supply pipe 92 flows into the second flow path 97.

[0061] The downstream end of the second flow path 97 opens inside the fourth bearing retainer 64. The fourth bearing retainer 64 supports the motor shaft 21 via the bearing 88. The hollow portion 22 of the motor shaft 21 opens inside the fourth bearing retainer 64. Fluid O flows from the second flow path 97 toward the inside of the fourth bearing retainer 64, and further into the inner flow path 96 of the motor shaft 21. As fluid O passes through the inside of the fourth bearing retainer 64, it is supplied to the bearing 88, lubricating the bearing 88.

[0062] The internal flow path 96 of the motor shaft is the path that passes through the hollow portion 22 of the motor shaft 21. That is, the internal flow path 96 of the motor shaft is provided on the motor shaft 21. In the internal flow path 96 of the motor shaft, fluid O flows axially. The first flow path 95 and the second flow path 97 are connected to the internal flow path 96 of the motor shaft. Fluid O flowing into the hollow portion 22 of the motor shaft 21 from one axial side and the other axial side merges in the internal flow path 96 of the motor shaft.

[0063] The fluid O passing through the flow path 96 inside the motor shaft is subjected to centrifugal force accompanying the rotation of the rotor 20, and is radially dispersed outward through the rotor 20, supplied to the stator 25. As the fluid O passes through the rotor 20, it absorbs heat from the rotor 20, cooling the rotor 20. Furthermore, the fluid O supplied radially inward to the stator 25 absorbs heat from the stator 25 as it moves along the surface of the stator 25, cooling the stator 25 from the inside.

[0064] According to this embodiment, a portion of the fluid O accumulated in the storage section P cools the motor 2 from the outside via the supply pipe section 92, and cools the motor 2 from the inside via the internal flow path section 96 of the motor shaft. That is, according to this embodiment, the fluid O can be used to cool both the inside and outside of the motor 2, thereby improving the cooling efficiency of the motor 2.

[0065] A portion of the fluid O passing through the flow path 96 inside the motor shaft leaks out through the gap between the connection between the first shaft portion 21A and the second shaft portion 21B to the outside of the motor shaft 21. The connection between the first shaft portion 21A and the second shaft portion 21B is located inside the shaft passage hole 6p of the partition wall 6b. The fluid O leaking out to the outside of the motor shaft 21 is supplied to the bearings 86 and 87 located inside the shaft passage hole 6p of the partition wall 6b to lubricate the bearings 86 and 87.

[0066] Alternatively, in this embodiment, either the second branch path 95b or the second flow path 97 can be omitted. That is, in this embodiment, a structure can be adopted in which fluid O is supplied to the flow path 96 inside the motor shaft only from one axial side or the other axial side.

[0067] According to this embodiment, the fluid path 90 has an internal flow path 91 that passes through the interior of the hollow shaft 45. The internal flow path 91 runs straight through the internal space of the gear housing 82. Therefore, according to this embodiment, a portion of the fluid path 90 from the storage section P to the supply pipe section 92 can be made shorter or straighter, and the pipe resistance within the fluid path 90 can be suppressed. As a result, the pump 8 can be made smaller, and the power consumption of the pump 8 can be reduced.

[0068] According to this embodiment, by setting a portion of the fluid path 90 inside the hollow shaft 45, compared to the case where the flow path from the pump outlet to the supply pipe is only formed by the holes in the wall of the housing, the processing cost of the housing 6 can be reduced, and the drive device 1 can be provided cheaply.

[0069] According to this embodiment, by providing a portion of the fluid path 90 inside the hollow shaft 45, fluid O can be supplied to the bearings 83 and 84 that support both ends of the hollow shaft 45. Therefore, the bearings 83 and 84 can be lubricated by fluid O without providing a separate oil supply path.

[0070] According to this embodiment, the second axis J2, which is the center of the hollow shaft 45, is located above the first axis J1, which is the center of the motor 2. Therefore, it is easy to arrange the hollow shaft 45 close to the supply pipe 92 on the upper side of the motor 2, and the relay flow path 94 connecting the hollow shaft inner flow path 91 and the supply pipe 92 can be shortened. As a result, the pipe resistance of the fluid path 90 from the hollow shaft inner flow path 91 to the supply pipe 92 can be suppressed.

[0071] Furthermore, according to this embodiment, the center of the hollow shaft 45 is located above the first axis J1, thus allowing the hollow shaft 45 to be separately disposed from the oil surface of the storage section P. Consequently, the secondary shaft gear 42 and the drive gear 43 disposed on the outer peripheral surface of the hollow shaft 45 are less likely to be immersed in the fluid O, and the stirring resistance of the applied fluid O can be suppressed when the secondary shaft gear 42 and the drive gear 43 rotate.

[0072] In this embodiment, the supply pipe section 92 is disposed on the second axis J2. According to this embodiment, the hollow shaft inner flow path section 91 and the supply pipe section 92 can be arranged in a straight line along the second axis J2. Therefore, by configuring the hollow shaft inner flow path section 91, the intermediate flow path section 94, and the supply pipe section 92 in a straight line, the flow path length can be shortened, and the pipe resistance of the fluid path 90 from the hollow shaft inner flow path section 91 to the supply pipe section 92 can be suppressed.

[0073] In this embodiment, the hollow portion 46 of the hollow shaft 45 extends axially with the same cross-sectional shape (circular in this embodiment). Therefore, the flow path portion 91 inside the hollow shaft of this embodiment has the same flow path cross-sectional area over its entire length. Similarly, the supply through hole 6s of this embodiment extends axially with the same cross-sectional shape (circular in this embodiment). Therefore, the relay flow path portion 94 of this embodiment has the same flow path cross-sectional area over its entire length.

[0074] In this embodiment, the cross-sectional area S2 of the intermediate flow path 94 is smaller than the cross-sectional area S1 of the hollow shaft inner flow path 91. According to this embodiment, when fluid O flows from the hollow shaft inner flow path 91 into the intermediate flow path 94, the flow velocity of fluid O increases. Therefore, the pressure of fluid O can be increased at the supply pipe 92 located downstream of the intermediate flow path 94, causing fluid O to be forcefully ejected from the injection hole 92h of the supply pipe 92, enabling fluid O to reach the inner part of the motor 2.

[0075] <Second Implementation> Figure 2 This is a schematic diagram of the drive device 101 according to the second embodiment. The main difference between the drive device 101 in this embodiment and the first embodiment is the structure of the fluid path 190 and the collection container 193. Furthermore, in the descriptions of the various embodiments described below, the same symbols are used for the constituent elements that are the same as those in the previously described embodiments, and their descriptions are omitted.

[0076] In this embodiment, a collection container (storage section) 193 is provided inside the gear storage section 82. The collection container 193 opens upward and stores fluid O. The collection container 193 is located above the second axis J2. Additionally, here, "the collection container 193 is located above the second axis J2" means that the bottom of the collection container 193 is located above the second axis J2.

[0077] The collection container 193 is, for example, a groove-shaped component protruding from the inner side of the gear receiving part 82. In this case, the collection container 193 is part of the outer casing 6. Alternatively, the collection container 193 may be a component different from the outer casing 6.

[0078] The collection container 193 functions as a storage unit for the accumulated fluid O. Therefore, the storage unit provided inside the housing 6 includes, in addition to the storage unit P provided in the lower region of the gear housing 82, the collection container 19 located above the storage unit P within the gear housing 82.

[0079] The fluid path 190 of this embodiment includes a lifting path 198, a first flow path 195, a hollow shaft inner flow path 91, a relay flow path 94, a supply tank (supply section) 192, a connecting flow path 199, and a motor shaft inner flow path 96.

[0080] The lifting path 198 is a path in which fluid O is lifted and guided to the collection container 193 by the rotation of the gear (gear ring 51 in this embodiment) of the power transmission mechanism 3. That is, in the fluid path 190 of this embodiment, fluid O is lifted by the gear of the power transmission mechanism 3 and supplied from the storage section P to the collection container 193.

[0081] In this embodiment, the storage section connected to the first flow path section 195 is a collection container 193. The first flow path section 195 connects the collection container 193 to the hollow shaft inner flow path section 91. Furthermore, the first flow path section 195 connects the collection container 193 to the connecting flow path section 199. The first flow path section 195 guides fluid O from the collection container 193 to the hollow shaft inner flow path section 91 and the connecting flow path section 199.

[0082] The connecting flow path 199 connects the first flow path 195 to the internal flow path 96 of the motor shaft. The connecting flow path 199 is a hole provided in the gear cover wall 6a. That is, the connecting flow path 199 is disposed inside the gear cover wall 6a. The connecting flow path 199 extends along the wall surface of the gear cover wall 6a.

[0083] The downstream end of the first flow path 195 opens inside the first bearing retaining portion 61. The hollow portion 46 of the hollow shaft 45 opens inside the first bearing retaining portion 61. Furthermore, the upstream end of the connecting flow path 199 opens inside the first bearing retaining portion 61. Fluid O flows from the first flow path 195 toward the inside of the first bearing retaining portion 61, and further branches into the inner flow path 91 of the hollow shaft and the connecting flow path 199, respectively. As fluid O passes through the inside of the first bearing retaining portion 61, it is supplied to the bearing 83, lubricating the bearing 83.

[0084] The downstream end of the connecting flow path 199 opens inside the second bearing retaining portion 62. The hollow portion 22 of the motor shaft 21 opens inside the second bearing retaining portion 62. Fluid O flows from the connecting flow path 199 into the inside of the second bearing retaining portion 62, and further into the inner flow path 96 of the motor shaft. Fluid O is supplied to the bearing 85 as it passes through the inside of the second bearing retaining portion 62, lubricating the bearing 85.

[0085] The supply trough 192 is a trough-shaped component disposed inside the motor housing 81. The supply trough 192 is connected to the downstream side of the relay flow path 94. The supply trough 192 extends axially. The supply trough 192 is located directly above the motor 2. A through hole 192h for supplying fluid O to the motor 2 is provided at the bottom of the supply trough 192. In this embodiment, the supply trough 192 allows the fluid O stored inside to drip from the through hole 192h at the bottom towards the motor 2. Additionally, "directly above" in this specification indicates an overlapping arrangement when viewed from above and from the top and bottom.

[0086] In this embodiment, the supply tank 192 is trough-shaped, allowing the fluid O stored inside to drip down through the through hole 192h and be supplied to the motor 2. Therefore, according to the supply tank 192 of this embodiment, even if the supply of fluid O from the storage unit P to the supply tank 192 stops, a small amount of fluid O stored in the supply tank 192 can be supplied to the motor 2 each time over a long period of time. Therefore, even if the supply of fluid O from the storage unit P to the supply tank 192 stops, the motor 2 can be cooled over a long period of time.

[0087] According to this embodiment, the collection container 193 is located above the second axis J2. Therefore, the fluid O in the collection container 193 is supplied to the hollow shaft inner flow path 91 and the motor shaft inner flow path 96 by gravity. Therefore, as shown in this embodiment, when the pump 8 is provided in the first flow path 195, the power consumption of the pump 8 can be reduced. Furthermore, by adopting the fluid path 190 of this embodiment, the fluid O in the collection container 193 can be supplied to the hollow shaft inner flow path 91 and the motor shaft inner flow path 96 by gravity. Therefore, in this embodiment, a structure that removes the pump 8 from the first flow path 195 can be adopted, and the drive device 101 can be provided inexpensively.

[0088] According to this embodiment, by being lifted by the power transmission mechanism 3, a portion of the fluid O accumulated in the storage section P is transferred and stored in the collection container 193. Therefore, the liquid level of the fluid O accumulated in the storage section P can be lowered, and the stirring resistance of the gears immersed in the fluid O in the storage section P can be suppressed.

[0089] <Third Implementation Method> Figure 3 This is a schematic diagram of the drive device 201 according to the third embodiment. The main difference between the drive device 201 in this embodiment and the first embodiment is the structure of the fluid path 290.

[0090] The fluid path 290 of this embodiment includes a first flow path section 295, a hollow shaft inner flow path section 91, a relay flow path section 94, and a supply pipe section 92. Compared with the above embodiment, the fluid path 290 of this embodiment does not have a second flow path section 97 and a motor shaft inner flow path section 96.

[0091] In this embodiment, the first flow path 295 connects the storage section P to the hollow shaft inner flow path 91. The first flow path 295 guides the fluid O accumulated in the storage section P to the hollow shaft inner flow path 91. The first flow path 295 is a hole provided in the gear cover wall section 6a. That is, the first flow path 295 is disposed inside the gear cover wall section 6a. The first flow path 295 extends along the wall surface of the gear cover wall section 6a.

[0092] According to this embodiment, similarly to the embodiment described above, the fluid path 290 traverses the internal space of the gear receiving portion 82 in a straight line at the flow path portion 91 within the hollow shaft. Therefore, the fluid path 290 can be shortened, suppressing pipeline resistance. In this embodiment, the fluid paths 90 and 190 do not necessarily have supply pipes (supply sections) 92 and 192. In this case, a cavity is provided inside the side wall of the motor housing 81. That is, the supply section can also be a cavity. The relay flow path 94 connects the hollow shaft inner flow path 91 to this cavity. This cavity extends axially inside the side wall of the motor housing 81. This cavity is disposed inside the side wall of the motor housing 81 on the upper side of the motor 2. A spray hole is provided on the side wall of the motor housing 81, opening towards the motor 2 and connected to the cavity. Fluid O passing through this cavity is sprayed towards the motor 2 from the spray hole provided on the side wall. Thus, the supply pipe 92 supplies fluid O from the outside of the motor 2 to the motor 2.

[0093] Various embodiments of the present invention have been described above. However, each structure and combination thereof in each embodiment is an example, and structural additions, omissions, substitutions, and other changes can be made without departing from the spirit of the present invention. Moreover, the present invention is not limited to the embodiments.

Claims

1. A driving device comprising: A motor having a motor shaft that rotates about a first axis; A power transmission mechanism, wherein the power transmission mechanism is connected to the motor shaft from one axial side; The housing includes a motor housing and a gear housing, the motor housing housing the motor internally, and the gear housing housing the power transmission mechanism internally; and A fluid path, at least a portion of which is disposed within the housing. The power transmission mechanism has a hollow shaft centered on a second axis parallel to the first axis. The fluid path has: A hollow shaft internal flow path section is provided in the hollow shaft; A supply unit, wherein the supply unit is disposed above the motor; and The relay flow path section connects the hollow shaft inner flow path section to the supply section. The motor shaft is hollow. The fluid path has an internal flow path section within the motor shaft, and the internal flow path section within the motor shaft is disposed on the motor shaft. The gear housing has a gear cover wall that covers the power transmission mechanism from one axial side. The fluid path has a first flow path portion, which is disposed inside the gear cover wall portion and extends along the wall surface of the gear cover wall portion. The first flow path has a main flow path and a first branch path and a second branch path branching off from the main flow path. The first branch path connects the downstream end of the main flow path to the end of the inner flow path of the hollow shaft. The second branch connects the downstream end of the main flow path to the end of the flow path within the motor shaft. The hollow shaft internal flow path is located on the upper side than the motor shaft internal flow path.

2. The driving device according to claim 1, wherein, The second axis is located above the first axis.

3. The driving device according to claim 1 or 2, wherein, The supply unit is positioned on the second axis.

4. The driving device according to claim 1 or 2, wherein, The system includes a pump, which is positioned within the path of the fluid path. A storage section is provided in the gear storage section. The pump is installed in the flow path that connects the storage section to the flow path section inside the hollow shaft.

5. The driving device according to claim 1 or 2, wherein, The motor housing has a motor cover wall portion that covers the motor from the other side of the axial direction. The fluid path has a second flow path section that connects the supply section to the flow path section inside the motor shaft. The second flow path is disposed inside the motor housing wall.

6. The driving device according to claim 1 or 2, wherein, The housing has a partition wall that divides the motor housing section and the gear housing section. The relay flow path is located in the partition wall. The cross-sectional area of ​​the flow path of the relay flow path is smaller than that of the flow path of the hollow shaft inner flow path.

7. The driving device according to claim 1 or 2, wherein, The supply section is tubular.

8. The driving device according to claim 1 or 2, wherein, The supply section is trough-shaped.

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