Drive unit

Abstract

To provide a driving device capable of suppressing pipeline resistance of a fluid passage by shortening the fluid passage through which fluid flows.SOLUTION: A driving device 1 includes: a motor 2 having a motor shaft 21 rotating around a first shaft line J1; a power transmission mechanism 3 connected to the motor shaft 21 from one side in an axial direction; a housing 6 having a motor housing part 81 housing the motor 2 inside and a gear housing part 82 housing the power transmission mechanism 3 inside; and a fluid passage 90 at least a part of which is arranged within the housing 6. The power transmission mechanism 3 has a hollow-like hollow shaft 45 with a second shaft line J2 parallel to the first shaft line J1 as a center. The fluid passage 90 has: a hollow shaft inside flow passage part 91 provided in the hollow shaft 45; a supply part 92 provided at an upper part of the motor 2; and a relay flow passage part 94 connecting the hollow shaft inside flow passage part 91 and the supply part 92.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a drive device. [Background technology]

[0002] In recent years, the development of drive systems for vehicles has progressed with the spread of electric and hybrid vehicles. Such drive systems store fluids such as oil inside to lubricate gear surfaces or cool rotating electrical machines. Patent Document 1 discloses a structure in which oil stored at the bottom of a housing case is pumped up and flows through a cooling pipe that passes above an electric motor, and is then supplied to the electric motor from the outlet of the cooling pipe. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-178520 Summary of the Invention [Problem to be solved by the invention]

[0004] In a drive device having a fluid path for circulating a fluid, as the length of the fluid path increases, the pipeline resistance of the fluid path increases, causing problems such as an increase in the size of the pump that pumps the fluid and an increase in the power consumption of the pump.

[0005] In view of the above-mentioned problems, one aspect of the present invention aims to provide a drive device that can reduce the pipeline resistance of a fluid path by shortening the fluid path through which the fluid flows. [Means for solving the problem]

[0006] One embodiment of the drive device of the present invention includes a motor having a motor shaft rotating about a first axis, a power transmission mechanism connected to one axial side of the motor shaft, a housing having a motor accommodating section that accommodates the motor and a gear accommodating section that accommodates the power transmission mechanism, 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 that is parallel to the first axis. The fluid path includes a hollow shaft internal flow path portion provided in the hollow shaft, a supply portion provided above the motor, and a relay flow path portion connecting the hollow shaft internal flow path portion and the supply portion. [Effects of the Invention]

[0007] According to one aspect of the present invention, there is provided a drive device that can reduce pipeline resistance by shortening a fluid path through which a fluid flows. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram of a drive device according to a first embodiment. [Figure 2] FIG. 2 is a schematic diagram of a drive device according to the second embodiment. [Figure 3] FIG. 3 is a schematic diagram of a drive device according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, a driving device according to an embodiment of the present invention will be described with reference to the drawings. In the following description, the vertical direction is defined based on the positional relationship when the drive device of the embodiment shown in each drawing is mounted on a vehicle positioned on a horizontal road surface. The drawings also appropriately illustrate an XYZ coordinate system as a three-dimensional Cartesian coordinate system. In the XYZ coordinate system, the Z axis direction is the vertical direction. The +Z side is the upper side in the vertical direction, and the -Z side is the lower side in the vertical direction. In the following description, the upper side in the vertical direction is simply referred to as the "upper side," and the lower side in the vertical direction is simply referred to as the "lower side." The X axis direction is perpendicular to the Z axis direction and corresponds to the longitudinal direction of the vehicle on which the drive device is mounted. 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 perpendicular to both the X axis direction and the Z axis direction and corresponds to the lateral 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 longitudinal direction and the lateral direction are horizontal directions perpendicular to the vertical direction.

[0010] A first axis J1, which is shown appropriately in each drawing, extends in 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 about the first axis J1 will be simply referred to as the "radial direction." In addition, in the following description, the +Y side may be simply referred to as one axial side, and the -Y side may be simply referred to as the other axial side.

[0011] First Embodiment FIG. 1 is a schematic diagram of a drive device 1 according to a first embodiment. The drive unit 1 is mounted on a vehicle powered by a motor, such as a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHV), or an electric vehicle (EV), and is used as the power source thereof.

[0012] The drive device 1 includes a motor 2, a power transmission mechanism 3, a housing 6, a fluid O accommodated inside the housing 6, a fluid path 90 through which the fluid O flows, a pump 8, and a plurality of bearings 83, 84, 85, 86, 87, 88, and 89.

[0013] (housing) The housing 6 has a motor accommodating section 81 that accommodates the motor 2 therein, and a gear accommodating section 82 that accommodates the power transmission mechanism 3 therein. The housing 6 also has a partition wall 6b that separates the internal space of the motor accommodating section 81 from the internal space of the gear accommodating section 82. The gear accommodating section 82 is located on one axial side (+Y side) of the motor accommodating section 81.

[0014] The partition wall 6b is provided with a supply through hole 6s, a shaft passing hole 6p, and a partition wall opening 6q. The supply through hole 6s, the shaft passing hole 6p, and the partition wall opening 6q connect the internal spaces of the motor accommodating portion 81 and the gear accommodating portion 82.

[0015] The motor accommodating section 81 has a motor peripheral wall 6g and a motor cover wall 6c. The motor peripheral wall 6g is cylindrical and extends axially with the first axis J1 as its center. The motor peripheral wall 6g surrounds the motor 2 from the radially outer side of the first axis J1. An opening on one axial side (+Y side) of the motor peripheral wall 6g is covered by a partition wall 6b, and an opening on the other axial side (-Y side) is covered by a motor cover wall 6c. The motor cover wall 6c extends along a plane perpendicular to the first axis J1. The motor cover wall 6c covers the motor 2 from the other axial side (-Y side).

[0016] The gear accommodating portion 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 along the axial direction. The gear peripheral wall portion 6f surrounds the gears 41, 42, 43, and 51 of the power transmission mechanism 3 from the radial outside of the first axis J1, the second axis J2, and the third axis J3 (described later). An opening on the other axial side (-Y side) of the gear peripheral wall portion 6f is covered by a partition wall 6b, and an 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 perpendicular 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 accommodated inside the housing 6. The fluid O circulates within a fluid path 90, which will be described later. In this embodiment, the fluid O is oil, and is used not only to cool the motor 2 but also to lubricate the power transmission mechanism 3. It is preferable to use, as the fluid O, an oil equivalent to a lubricating oil for automatic transmissions (ATF: Automatic Transmission Fluid), which has a relatively low viscosity, in order to function as both a lubricating oil and a cooling oil.

[0018] A reservoir P for storing fluid O is provided in a lower region within the gear accommodating portion 82. The fluid O stored in the reservoir P is scooped up by the operation of the power transmission mechanism 3 and diffused within the gear accommodating portion 82. The fluid O diffused within the gear accommodating portion 82 spreads over the tooth surfaces of the power transmission mechanism 3 and is used to lubricate the power transmission mechanism 3. The fluid O in the reservoir P is also supplied to the motor 2 through a fluid path 90.

[0019] (Motor) In this embodiment, the motor 2 is an inner rotor motor. The motor 2 is, for example, a three-phase AC motor. The motor 2 functions both as an electric motor and as a generator. The 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. The motor shaft 21 is provided with a hollow portion 22 that extends axially and is open at both ends.

[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 accommodating 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 accommodating portion 82. The power transmission mechanism 3 is connected to the second shaft portion 21B.

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

[0024] The rotor 20 is rotatable about a first axis J1. The rotor 20 includes 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 from the radially outer side. The stator 25 has a stator core, a coil attached to the stator core, and an insulator (not shown) interposed between the stator core and the coil. The stator 25 is held in the housing 6. The stator core has a plurality of magnetic pole teeth (not shown) extending radially inward from the inner circumferential surface of the annular yoke. Coil wire is arranged between the magnetic pole teeth. The coil wire located in the gap between adjacent magnetic pole teeth constitutes a coil. 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 by means of a plurality of 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 a function of reducing the rotational speed of the motor 2 and increasing the torque output from the motor 2 in accordance with 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 has a pinion gear 41, a hollow shaft 45, and a counter gear 42 and a drive gear 43 fixed to the hollow shaft 45. That is, the power transmission mechanism 3 has a plurality of gears 41, 42, 43 and the hollow shaft 45. Torque output from the motor 2 is transmitted to a ring gear 51 of the differential device 5 via the motor shaft 21 of the motor 2, the pinion gear 41, the counter gear 42, and the drive gear 43. The gear ratio of each gear, the number of gears, etc. can be changed in various ways depending on the required reduction ratio.

[0029] The pinion gear 41 is fixed to the outer peripheral surface of the motor shaft 21 of the motor 2. The pinion gear 41 rotates together with the motor shaft 21 about the first axis J1.

[0030] The hollow shaft 45 extends along a second axis J2 that is 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 around the second axis J2. The hollow shaft 45 is hollow. The hollow shaft 45 is provided with a hollow portion 46 that extends along the axial direction and is open at both ends.

[0031] The counter gear 42 and the drive gear 43 are arranged side by side in the axial direction. The counter gear 42 and the drive gear 43 are provided on the outer circumferential surface of a hollow shaft 45. The counter gear 42 and the drive gear 43 are connected via the hollow shaft 45. The counter gear 42 and the drive gear 43 rotate about the second axis J2. At least two of the counter gear 42, the drive gear 43, and the hollow shaft 45 may be configured from a single member. The counter gear 42 meshes with the pinion gear 41. The drive gear 43 meshes with a ring gear 51 of the differential device 5.

[0032] The differential 5 is a device for transmitting the torque output from the motor 2 to the wheels of the vehicle. When the vehicle turns, the differential 5 has the function of transmitting the same torque to a pair of output shafts 55 while absorbing the speed difference between the left and right wheels.

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

[0034] The pair of output shafts 55 extend along the axial direction. One end of each of the pair of output shafts 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 ring gear 51 has a larger diameter than the other gears. Furthermore, at least a portion of the ring gear 51 is immersed in the reservoir P. Therefore, the power transmission mechanism 3 scoops up the fluid O in the reservoir P when the ring gear 51 is driven.

[0036] (bearing) A plurality of bearings 83, 84, 85, 86, 87, 88, and 89 are held in the housing 6 and rotatably support either the motor shaft 21, the hollow shaft 45, or the output shaft 55, respectively.

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

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

[0039] The gear cover wall 6a has a first bearing retaining portion 61 that retains the bearing 83 and a second bearing retaining portion 62 that retains the bearing 85. The partition wall 6b has a third bearing retaining portion 63 that retains the bearing 84. The motor cover wall 6c has a fourth bearing retaining portion 64 that retains the bearing 88. The first bearing retaining portion 61 and the third bearing retaining portion 63 are cylindrical and centered on the second axis J2. The second bearing retaining portion 62 and the fourth bearing retaining portion 64 are cylindrical and centered on the 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 accommodating portion 82.

[0040] (fluid path) The fluid O circulates through a fluid path 90 within the drive unit 1. The fluid path 90 supplies the fluid O from a reservoir P to the motor 2 and returns the fluid O to the reservoir P. At least a portion of the fluid path 90 is disposed within the housing 6.

[0041] In this specification, "fluid" route " refers to the path of the fluid O circulating within the housing 6. route " is a concept that includes not only a "flow path" that forms a steady flow of fluid in one direction, but also a path that temporarily retains fluid (e.g., a reservoir), a path along which fluid drips, and a path along which fluid splashes.

[0042] A pump 8 is provided in the fluid path 90. The pump 8 pumps the fluid O in the fluid path 90. The pump 8 is fixed to the outer surface of the gear accommodating portion 82. The pump 8 pumps the fluid O in the fluid path 90. The pump 8 may be an electric pump that is driven by electricity, or a mechanical pump that operates in conjunction with the driving of the power transmission mechanism 3.

[0043] Furthermore, a cooler that cools the fluid O may be further provided in the fluid path 90. This allows the motor 2 to be efficiently cooled via the fluid O. The cooler may be provided in the reservoir P and cool the fluid O that accumulates in the reservoir P.

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

[0045] The first flow path section 95 connects the reservoir section P with the hollow shaft internal flow path section 91 and the motor shaft internal flow path section 96. The first flow path section 95 guides the fluid O that accumulates in the reservoir section P to the hollow shaft internal flow path section 91 and the motor shaft internal flow path section 96.

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

[0047] The first flow path section 95 has a main flow path 95c, and a first branch path 95a and a second branch path 95b branching from the main flow path 95c. The main flow path 95c is provided in an upstream region of the first flow path section 95. An upstream end of the main flow path 95c opens to the reservoir P.

[0048] The first branched passage 95a connects the downstream end of the main passage 95c and the end of the hollow-shaft internal passage portion 91. The downstream end of the first branched passage 95a opens inside the first bearing holder 61. The first bearing holder 61 supports the hollow shaft 45 via the bearing 83. The hollow portion 46 of the hollow shaft 45 opens inside the first bearing holder 61. The fluid O flows from the first branched passage 95a into the inside of the first bearing holder 61 and further into the hollow-shaft internal passage portion 91 of the hollow shaft 45. In addition, the fluid O is supplied to the bearing 83 as it passes inside the first bearing holder 61, lubricating the bearing 83.

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

[0050] In this embodiment, a pump 8 is disposed in the main flow path 95c of the first flow path section 95. The pump 8 is provided in a flow path connecting the reservoir P and the hollow shaft internal flow path section 91, and sends fluid O from the reservoir P to the hollow shaft internal flow path section 91. The pump 8 is also provided in a flow path connecting the reservoir P and the motor shaft internal flow path section 96, and sends fluid O from the reservoir P to the motor shaft internal flow path section 96. According to this embodiment, by providing the pump 8 in the main flow path 95c located upstream of the first branch path 95a and the second branch path 95b, it is possible to supply fluid O to the two internal flow paths (the hollow shaft internal flow path section 91 and the motor shaft internal flow path section 96) with a single pump 8.

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

[0052] The relay flow path portion 94 connects the hollow shaft inner flow path portion 91 and the supply pipe portion 92. The relay flow path portion 94 is a flow path provided inside the supply through-hole 6s of the partition wall 6b. Therefore, the relay flow path portion 94 extends linearly along the axial direction inside the partition wall 6b.

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

[0054] The downstream end of the relay flow path section 94 is Motor accommodating section 81 The relay flow path section 94 has an opening at its downstream end, and the end of the supply pipe section 92 on one axial side (+Y side) is inserted into the opening at the downstream end of the relay flow path section 94. Therefore, the fluid O flowing through the relay flow path section 94 flows into the supply pipe section 92 at the downstream end of the relay flow path section 94.

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

[0056] The supply pipe section 92 is disposed above the motor 2 inside the motor housing section 81. The supply pipe section 92 is provided with an injection hole 92h that opens toward the motor 2. The fluid O passing through the supply pipe section 92 is injected toward the motor 2 from the injection hole 92h provided in the supply pipe section 92. In this way, the supply pipe section 92 supplies the fluid O to the motor 2 from outside the motor 2.

[0057] The supply pipe 92 in this embodiment is pipe-shaped. Therefore, by using the pump 8 to pump the fluid O into 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 toward the motor 2. This allows the fluid O to reach even the complicated parts of the motor 2, thereby efficiently cooling the motor 2.

[0058] The fluid O supplied from the outside to the motor 2 through the supply pipe 92 absorbs heat from the stator 25 as it flows along the surface of the stator 25, cooling the stator 25. The fluid O then drips from the stator 25 to reach a lower region within the motor housing 81, and then returns to the reservoir P through the partition opening 6q.

[0059] The second flow path portion 97 connects the supply pipe portion 92 and the motor shaft internal flow path portion 96. The second flow path portion 97 is a hole provided in the motor cover wall portion 6c. In other words, the second flow path portion 97 is disposed inside the motor cover wall portion 6c. The second flow path portion 97 extends along the wall surface of the motor cover wall portion 6c.

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

[0061] The downstream end of the second flow path portion 97 opens inside the fourth bearing holder 64. The fourth bearing holder 64 supports the motor shaft 21 via the bearing 88. The hollow portion 22 of the motor shaft 21 opens inside the fourth bearing holder 64. The fluid O flows from the second flow path portion 97 into the inside of the fourth bearing holder 64, and further flows into the motor shaft internal flow path portion 96 of the motor shaft 21. The fluid O is supplied to the bearing 88 as it passes inside the fourth bearing holder 64, and lubricates the bearing 88.

[0062] The motor shaft internal flow path 96 is a path that passes through the hollow portion 22 of the motor shaft 21. That is, the motor shaft internal flow path 96 is provided in the motor shaft 21. In the motor shaft internal flow path 96, the fluid O flows along the axial direction. A first flow path 95 and a second flow path 97 are connected to the motor shaft internal flow path 96. The fluid O that flows into the hollow portion 22 of the motor shaft 21 from one axial side and the other axial side join together in the motor shaft internal flow path 96.

[0063] The fluid O passing through the motor shaft inner flow path portion 96 is subjected to centrifugal force caused by the rotation of the rotor 20, and passes radially outward through the rotor 20, scattering radially outward, and is supplied to the stator 25. As the fluid O passes through the rotor 20, it absorbs heat from the rotor 20, thereby cooling the rotor 20. Furthermore, the fluid O supplied to the stator 25 from the radially inner side absorbs heat from the stator 25 as it flows along the surface of the stator 25, thereby cooling the stator 25 from the inside.

[0064] According to this embodiment, a portion of the fluid O stored in the reservoir P cools the motor 2 from the outside via the supply pipe 92, and cools the motor 2 from the inside via the motor shaft inner flow path 96. That is, according to this embodiment, the fluid O can be used to cool 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 motor shaft internal flow path 96 leaks out of the motor shaft 21 from a gap at the connection between the first shaft portion 21A and the second shaft portion 21B. The connection between the first shaft portion 21A and the second shaft portion 21B is disposed inside the shaft passing hole 6p of the partition wall 6b. The fluid O leaking out of the motor shaft 21 is supplied to the bearings 86, 87 disposed inside the shaft passing hole 6p of the partition wall 6b, and lubricates the bearings 86, 87.

[0066] Note that this embodiment may employ a configuration in which either the second branch passage 95b or the second flow path portion 97 is omitted. That is, this embodiment may employ a configuration in which the fluid O is supplied to the motor shaft internal flow path portion 96 from only one axial side or the other axial side.

[0067] According to this embodiment, the fluid path 90 has an inner hollow shaft flow path portion 91 that passes through the interior of the hollow shaft 45. The inner hollow shaft flow path portion 91 traverses the internal space of the gear accommodating portion 82 in a straight line. Therefore, according to this embodiment, a portion of the fluid path 90 that reaches the supply pipe portion 92 from the reservoir portion P can be configured to be short and straight, and the pipeline resistance within the fluid path 90 can be suppressed. As a result, the pump 8 can be made smaller and its power consumption can be reduced.

[0068] According to this embodiment, a portion of the fluid path 90 is provided inside the hollow shaft 45, which reduces the processing costs of the housing 6 compared to when the flow path from the pump outlet to the supply pipe section is composed only of a hole in the wall of the housing, and the drive unit 1 can be provided at low cost.

[0069] According to the present embodiment, a portion of the fluid path 90 is provided inside the hollow shaft 45, so that the fluid O can be supplied to the bearings 83, 84 that support both ends of the hollow shaft 45. Therefore, the bearings 83, 84 can be lubricated by the 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. This makes it easy to arrange the hollow shaft 45 close to the supply pipe 92 above the motor 2, and it is possible to shorten the relay flow path 94 that connects the hollow shaft internal flow path 91 and the supply pipe 92. This makes it possible to reduce the pipeline resistance of the fluid path 90 from the hollow shaft internal flow path 91 to the supply pipe 92.

[0071] Additionally, according to the present embodiment, the center of the hollow shaft 45 is located above the first axis J1, so that the hollow shaft 45 can be disposed far away from the oil surface in the reservoir P. This makes it difficult for the counter gear 42 and the drive gear 43, which are provided on the outer peripheral surface of the hollow shaft 45, to be immersed in the fluid O in the reservoir P, and makes it possible to suppress the application of agitation resistance to the fluid O when the counter gear 42 and the drive gear 43 rotate.

[0072] In the present embodiment, the supply pipe section 92 is disposed on the second axis J2. According to the present embodiment, the hollow shaft inner flow path section 91 and the supply pipe section 92 can be disposed in a straight line along the second axis J2. This allows the hollow shaft inner flow path section 91, the relay flow path section 94, and the supply pipe section 92 to be configured in a straight line, shortening the flow path length and reducing the pipeline resistance of the fluid path 90 from the hollow shaft inner flow path section 91 to the supply pipe section 92.

[0073] The hollow portion 46 of the hollow shaft 45 of this embodiment extends in the axial direction with a uniform cross-sectional shape (circular in this embodiment). Therefore, the hollow-shaft inner flow path portion 91 of this embodiment has a uniform flow path cross-sectional area along its entire length. Similarly, the supply through-hole 6s of this embodiment extends in the axial direction with a uniform cross-sectional shape (circular in this embodiment). Therefore, the relay flow path portion 94 of this embodiment has a uniform flow path cross-sectional area along its entire length.

[0074] In the present embodiment, the flow path cross-sectional area S2 of the relay flow path section 94 is smaller than the flow path cross-sectional area S1 of the hollow shaft inner flow path section 91. According to the present embodiment, the flow velocity of the fluid O is increased when it flows from the hollow shaft inner flow path section 91 into the relay flow path section 94. This increases the pressure of the fluid O in the supply pipe section 92 located downstream of the relay flow path section 94, allowing the fluid O to be forcefully ejected from the ejection holes 92h of the supply pipe section 92, and enabling the fluid O to reach deep inside the motor 2.

[0075] Second Embodiment FIG. 2 is a schematic diagram of a driving device 101 according to the second embodiment. The driving device 101 of this embodiment differs from the first embodiment mainly in the configurations of the fluid path 190 and the catch tank 193. In the following description of each embodiment, the same components as those in the previously described embodiments are denoted by the same reference numerals, and the description thereof will be omitted.

[0076] In this embodiment, a catch tank (storage portion) 193 is provided inside the gear accommodating portion 82. The catch tank 193 opens upward and stores the fluid O. The catch tank 193 is provided above the second axis J2. Here, "the catch tank 193 is provided above the second axis J2" means that the bottom of the catch tank 193 is located above the second axis J2.

[0077] The catch tank 193 is, for example, a gutter-shaped member that protrudes from the inner surface of the gear accommodating portion 82. In this case, the catch tank 193 is part of the housing 6. The catch tank 193 may also be a member separate from the housing 6.

[0078] The catch tank 193 functions as a reservoir that stores the fluid O. Therefore, the reservoirs provided inside the housing 6 include the reservoir P provided in the lower region of the gear accommodating portion 82, as well as the catch tank 193 located above the reservoir P within the gear accommodating portion 82.

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

[0080] The scooping path 198 is a path that scoops up the fluid O by rotation of a gear (ring gear 51 in this embodiment) of the power transmission mechanism 3 and guides it to the catch tank 193. That is, in the fluid path 190 of this embodiment, the fluid O is supplied from the reservoir P to the catch tank 193 by being scooped up by the gear of the power transmission mechanism 3.

[0081] In this embodiment, the reservoir connected to the first flow path section 195 is the catch tank 193. The first flow path section 195 connects the catch tank 193 and the hollow shaft inner flow path section 91. The first flow path section 195 also connects the catch tank 193 and the communication flow path section 199. The first flow path section 195 guides the fluid O from the catch tank 193 to the hollow shaft inner flow path section 91 and the communication flow path section 199.

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

[0083] The downstream end of the first flow path portion 195 opens inside the first bearing holder 61. The hollow portion 46 of the hollow shaft 45 opens inside the first bearing holder 61. Furthermore, the upstream end of the communication flow path portion 199 opens inside the first bearing holder 61. The fluid O flows from the first flow path portion 195 into the inside of the first bearing holder 61, and then branches off to flow into the hollow shaft internal flow path portion 91 and the communication flow path portion 199. The fluid O is supplied to the bearing 83 as it passes inside the first bearing holder 61, and lubricates the bearing 83.

[0084] The downstream end of the communication flow path portion 199 opens inside the second bearing holder 62. The hollow portion 22 of the motor shaft 21 opens inside the second bearing holder 62. The fluid O flows from the communication flow path portion 199 into the inside of the second bearing holder 62, and further flows into the motor shaft internal flow path portion 96. The fluid O is supplied to the bearing 85 as it passes inside the second bearing holder 62, and lubricates the bearing 85.

[0085] The supply gutter 192 is a gutter-shaped member disposed inside the motor accommodating section 81. The supply gutter 192 is connected to the downstream side of the relay flow path 94. The supply gutter 192 extends along the axial direction. The supply gutter 192 is located directly above the motor 2. A through-hole 192h is provided at the bottom of the supply gutter 192, through which the fluid O is supplied to the motor 2. The supply gutter 192 of this embodiment drips the fluid O stored inside from the through-hole 192h at the bottom toward the motor 2. In this specification, "directly above" means arranged above and overlapping when viewed from the vertical direction.

[0086] In this embodiment, supply gutter 192 is gutter-shaped, and fluid O stored therein is supplied to motor 2 by dripping from through-holes 192h. Therefore, supply gutter 192 of this embodiment can supply the fluid O stored in supply gutter 192 to motor 2 little by little over a long period of time, even if the supply of fluid O from reservoir P to supply gutter 192 is interrupted. Therefore, even if the supply of fluid O from reservoir P to supply gutter 192 is interrupted, motor 2 can be cooled over a long period of time.

[0087] According to the present embodiment, the catch tank 193 is located above the second axis J2. Therefore, the fluid O in the catch tank 193 is supplied to the hollow shaft internal flow path portion 91 and the motor shaft internal flow path portion 96 by utilizing gravity. Therefore, as shown in the present embodiment, when a pump 8 is provided in the first flow path portion 195, the power consumption of the pump 8 can be reduced. Furthermore, by employing the fluid path 190 of the present embodiment, the fluid O in the catch tank 193 can be supplied to the hollow shaft internal flow path portion 91 and the motor shaft internal flow path portion 96 by utilizing gravity. Therefore, in the present embodiment, a configuration in which the pump 8 is not provided in the first flow path portion 195 can be employed, and an inexpensive drive unit 101 can be provided.

[0088] According to the present embodiment, a portion of the fluid O accumulated in the reservoir P is transferred to and stored in the catch tank 193 by being scooped up by the power transmission mechanism 3. This allows the level of the fluid O accumulated in the reservoir P to be lowered, and the stirring resistance of the gears immersed in the fluid O in the reservoir P can be suppressed.

[0089] <Third embodiment> FIG. 3 is a schematic diagram of a driving device 201 according to the third embodiment. The driving device 201 of this embodiment differs from the first embodiment mainly in the configuration of the fluid path 290.

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

[0091] The first flow path section 295 of this embodiment connects the reservoir P and the hollow-shaft internal flow path section 91. The first flow path section 295 guides the fluid O that accumulates in the reservoir P to the hollow-shaft internal flow path section 91. The first flow path section 295 is a hole section provided in the gear cover wall section 6a. That is, the first flow path section 295 is disposed inside the gear cover wall section 6a. The first flow path section 295 extends along the wall surface of the gear cover wall section 6a.

[0092] According to this embodiment, similarly to the above-described embodiment, the fluid path 290 linearly crosses the internal space of the gear accommodating portion 82 in the hollow shaft inner flow path portion 91. Therefore, the fluid path 290 can be shortened, and the pipeline resistance can be suppressed.

[0093] Although various embodiments of the present invention have been described above, the configurations and combinations thereof in each embodiment are merely examples, and additions, omissions, substitutions, and other modifications of the configurations are possible without departing from the spirit of the present invention. Furthermore, the present invention is not limited to the embodiments. [Explanation of symbols]

[0094] 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 accommodating section, 82...gear accommodating section, 90,190,290...fluid path, 91...hollow shaft inner flow path section, 92...supply pipe section (supply section), 94...relay flow path section, 95,195,295...first flow path section, 96...motor shaft inner flow path section, 97...second flow path section, 192...supply gutter section (supply section), 193...catch tank (storage section), 198...path, J1...first axis, J2...second axis, O...fluid, P...storage section, S1,S2...flow path cross-sectional area

Claims

1. a motor having a motor shaft that rotates about a first axis; a power transmission mechanism connected to the motor shaft from one axial side; a housing having a motor accommodating portion that accommodates the motor therein and a gear accommodating portion that accommodates the power transmission mechanism therein; a fluid path at least partially disposed within the housing; the power transmission mechanism has a hollow shaft centered on a second axis parallel to the first axis, the motor shaft is hollow and extends into the gear accommodating portion at one axial side thereof, the gear accommodating portion has a gear cover wall portion that covers the power transmission mechanism from one axial side, The fluid path includes: a hollow shaft inner flow path portion provided in the hollow shaft; a supply unit provided above the motor; a relay flow path portion connecting the hollow shaft inner flow path portion and the supply portion; a motor shaft internal flow path portion provided in the motor shaft; a first flow path portion that is provided inside the gear cover wall portion, extends along a wall surface of the gear cover wall portion, and is capable of supplying fluid to one axial end of the hollow shaft internal flow path portion and one axial end of the motor shaft internal flow path portion, the first flow path portion has a first branch path and a second branch path branching from the first branch path, the first branch passage is connected at a downstream end thereof to one axial end of the hollow shaft internal flow passage portion, the second branch passage is connected at a downstream end thereof to one axial end of the flow passage portion within the motor shaft, a vertical position of the hollow shaft internal flow path portion and a vertical position of the motor shaft internal flow path portion are different from each other; Drive unit.

2. The second axis is located above the first axis. The drive device according to claim 1 .

3. The supply unit is disposed on the second axis.

3. The drive device according to claim 1 or 2.

4. a pump provided in the fluid path; The gear accommodating portion is provided with a storage portion, The pump is provided in a flow path connecting the storage section and the hollow shaft inner flow path section. The drive device according to any one of claims 1 to 3.

5. The gear accommodating portion is provided with a storage portion provided above the second axis, The fluid path is provided with the first flow path portion connecting the storage portion and the hollow shaft inner flow path portion. The drive device according to any one of claims 1 to 3.

6. The motor accommodating section has a motor cover wall section that covers the motor from the other axial side, The fluid path includes: a second flow path portion connecting the supply portion and the motor shaft internal flow path portion, The second flow path portion is disposed inside the motor cover wall portion. The drive device according to any one of claims 1 to 5.

7. the housing has a partition wall that separates the motor accommodating portion from the gear accommodating portion, The relay flow path portion is provided in the partition wall, a flow path cross-sectional area of ​​the relay flow path portion is smaller than a flow path cross-sectional area of ​​the hollow shaft inner flow path portion; The drive device according to any one of claims 1 to 6.

8. The supply section is pipe-shaped. The drive device according to any one of claims 1 to 7.

9. The supply section is trough-shaped. The drive device according to any one of claims 1 to 7.

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