阅读说明：本技术 左右轮驱动装置 (Left and right wheel driving device ) 是由 千叶元晴 寺尾公伸 高桥直树 于 2019-12-24 设计创作，主要内容包括：左右轮驱动装置(10)具备：壳体(15),具有贮存油的贮存部(18)；吸引口(19),配置于贮存部(18),并用于吸出贮存部(18)内的油；以及两个齿轮(34),具有螺旋线状的齿线,被支承为能够沿绕着旋转轴(13)的至少一个方向(D)旋转,被安装在向车辆的左右轮传递动力的动力传递路径上并且该两个齿轮彼此远离。吸引口(19)位于两个齿轮(34)之间。另外,各齿轮(34)以一部分浸没于贮存部(18)内的油的状态在旋转轴(13)的轴向上与吸引口(19)错开地配置,并且齿线向一个方向(D)且远离吸引口(19)的方向延伸。(A left-right wheel drive device (10) is provided with: a housing (15) having a reservoir (18) for storing oil; a suction port (19) which is disposed in the reservoir (18) and sucks out the oil in the reservoir (18); and two gears (34) having a helical tooth trace, supported so as to be rotatable in at least one direction (D) around the rotating shaft (13), mounted on power transmission paths that transmit power to the left and right wheels of the vehicle, and spaced apart from each other. The suction port (19) is located between the two gears (34). Each gear (34) is disposed offset from the suction port (19) in the axial direction of the rotating shaft (13) in a state in which a part thereof is immersed in the oil in the reservoir (18), and the tooth line extends in one direction (D) and in a direction away from the suction port (19).)

1. A left-right wheel driving device is characterized by comprising:

a housing having a reservoir portion that stores oil;

a suction port disposed in the reservoir portion for sucking out the oil in the reservoir portion; and

two gears having a helical-shaped tooth trace, supported so as to be rotatable in at least one direction about a rotation axis, mounted on a power transmission path that transmits power to left and right wheels of a vehicle and spaced apart from each other,

the suction port is positioned between the two gears,

each of the gears is disposed so as to be offset from the suction port in the axial direction of the rotary shaft with a portion of the gear immersed in the oil in the reservoir, and the tooth line extends in the one direction and in a direction away from the suction port.

2. Left and right wheel drive apparatus according to claim 1,

the two gears are a first gear installed on a power transmission path of the first motor and the second motor that drive the left and right wheels, and a second gear installed on a power transmission path of the second motor.

3. The left-right wheel drive device according to claim 2, comprising:

a gear mechanism that amplifies and distributes a torque difference of the first motor and the second motor to each of the left and right wheels,

the first gear and the second gear are configured to sandwich the gear mechanism therebetween.

4. The left-right wheel driving device according to any one of claims 1 to 3,

the one direction is a rotational direction in a case where the vehicle advances.

5. The left-right wheel drive device according to any one of claims 1 to 4, comprising:

an upstream gear mounted to a first shaft to which power is initially input;

a first intermediate gear that is attached to a second shaft arranged in parallel with the first shaft and that meshes with the upstream gear; and

a second intermediate gear mounted to the second shaft and having a different diameter than the first intermediate gear,

the rotation axis is arranged parallel to the first axis,

at least one of the two gears is attached to the rotary shaft and meshed with the second intermediate gear,

the first intermediate gear and the second intermediate gear each have a helical tooth trace extending in a direction opposite to the tooth trace of the gear meshing with the second intermediate gear.

Technical Field

The present invention relates to a left and right wheel drive device for guiding oil through a tooth line of a gear.

Background

Conventionally, there is a device that distributes power or shifts gears via a plurality of gears as a mechanism for transmitting a drive source (engine, motor) from a vehicle. For example, a device is known in which a planetary gear mechanism is incorporated in a differential device to change the distribution of drive torque of left and right wheels. In such a device, oil is generally supplied into a housing that houses various components such as gears, rotating shafts, and bearings in order to cool and lubricate these components.

For example, patent document 1 describes the following structure: a plurality of oil passages (oil grooves, oil holes, oil reservoirs, etc.) are formed in a gear housing (casing) into which oil is supplied, and oil carried up by rotation of a gear (gear) is supplied to a bearing through these oil passages. According to this configuration, the oil carried up by the gears is supplied to the differential device of the vehicle, whereby the differential device can be lubricated favorably.

Documents of the prior art

Patent document

Patent document 1: japanese patent No. 3678904

Technical problem to be solved by the invention

As described in patent document 1, when oil is supplied into a housing that houses components such as gears and bearings, a reservoir for storing oil is provided in the housing. Further, a suction port for sucking out oil is disposed in the reservoir. When a sufficient amount of oil is accumulated in the reservoir to such an extent that the entire suction port is submerged, the oil is appropriately sucked out through the suction port. On the other hand, in the case where the suction port is not entirely submerged in the oil due to the reduction of the oil in the reservoir or the inclination of the oil surface, air enters the suction port, and the oil may not be appropriately sucked out. Therefore, a technique for easily sucking out the oil in the reservoir (improving the suction performance) is required.

Disclosure of Invention

The present invention has been made in view of the above-mentioned problems, and an object thereof is to improve the oil suction performance in the casing. The present invention is not limited to this object, and is also another object of the present invention, in which operational effects derived from configurations showing an embodiment for carrying out the present invention described later, effects that cannot be obtained by the conventional techniques, and the like.

Means for solving the problems

(1) The left and right wheel drive device disclosed herein includes: a housing having a reservoir portion that stores oil; a suction port disposed in the reservoir portion for sucking out the oil in the reservoir portion; and two gears having a helical tooth trace, supported so as to be rotatable in at least one direction around a rotation axis, attached to a power transmission path that transmits power to left and right wheels of a vehicle, and spaced apart from each other, wherein the suction port is located between the two gears, each of the gears is disposed so as to be offset from the suction port in an axial direction of the rotation axis in a state in which a part of the gear is immersed in the oil in the reservoir, and the tooth trace extends in the one direction and in a direction away from the suction port. The gears are also called helical (helical) gears and helical gears.

(2) Preferably, the two gears are a first gear installed on a power transmission path of the first motor of the first and second motors driving the left and right wheels, and a second gear installed on a power transmission path of the second motor.

(3) Preferably, the left-right wheel drive device includes a gear mechanism that amplifies a torque difference between the first motor and the second motor and distributes the amplified torque difference to each of the left and right wheels, and the first gear and the second gear are disposed so as to sandwich the gear mechanism therebetween.

(4) Preferably, the one direction is a rotation direction in a case where the vehicle advances.

(5) Preferably, the left and right wheel drive device includes: an upstream gear mounted to a first shaft to which power is initially input; a first intermediate gear that is attached to a second shaft arranged in parallel with the first shaft and that meshes with the upstream gear; and a second intermediate gear attached to the second shaft and having a different diameter from the first intermediate gear, wherein the rotating shaft is disposed parallel to the first shaft, at least one of the two gears is attached to the rotating shaft and meshes with the second intermediate gear, and the first intermediate gear and the second intermediate gear each have a helical tooth trace extending in a direction opposite to the tooth trace of the gear meshing with the second intermediate gear.

Effects of the invention

According to the left-right wheel drive device of the present invention, when the two gears rotate in one direction, the oil that has entered the tooth lines of the respective gears is brought up to the suction port side, and therefore, the oil can be collected to the suction port. Therefore, the oil suction performance can be improved.

Drawings

Fig. 1 is a schematic sectional view of a left-right wheel drive device of an embodiment.

Fig. 2 is a schematic side view showing an internal structure of the left and right wheel drive apparatus of fig. 1.

Detailed Description

A left-right wheel drive device according to an embodiment will be described with reference to the drawings. The embodiments described below are merely examples, and various modifications and technical applications that are not explicitly described in the embodiments below are not intended to be excluded. The respective configurations of the present embodiment can be implemented by being variously modified within a range not departing from the gist thereof. Further, selection can be made as necessary, or appropriate combinations can be made. In the following description, the traveling direction of a vehicle to which the left and right wheel drive devices are applied is defined as the forward direction (vehicle forward direction), and the left and right directions are also referred to as "vehicle width directions" with reference to a state of facing forward. The direction of action of gravity is referred to as downward, and the opposite direction is referred to as upward.

[1. Structure ]

[1-1. Overall Structure ]

As shown in fig. 1, a left-right wheel drive device 10 (hereinafter, simply referred to as "drive device 10") according to the present embodiment. The drive device 10 is a differential device having an AYC (active yaw control) function, and is mounted between left and right wheels of a vehicle. The AYC function is the following function: the yaw moment is adjusted by actively controlling the distribution ratio of the driving force (driving torque) to the left and right driving wheels, thereby stabilizing the attitude of the vehicle in the yaw direction. The drive device 10 of the present embodiment has not only the AYC function but also a function of transmitting a rotational force to the left and right wheels to thereby cause the vehicle to run, and a function of passively absorbing a difference in rotational speed between the left and right wheels that occurs when the vehicle turns.

The drive device 10 includes: a first motor 1 and a second motor 2 for driving left and right wheels; a reduction gear train for reducing and transmitting the rotation speeds of the first motor 1 and the second motor 2; and a gear mechanism 3 that amplifies and distributes (transmits) a torque difference of the first motor 1 and the second motor 2 to each of the left and right wheels. The first motor 1 is disposed on the left side of the vehicle, and the second motor 2 is disposed on the right side. The first motor 1 and the second motor 2 are ac motors driven by electric power of a battery, not shown, and preferably have substantially the same output characteristics. The torque of the left and right driving wheels is variable, and the torque difference between the first motor 1 and the second motor 2 is amplified in the gear mechanism 3 and transmitted to the left and right wheels, respectively.

The first motor 1 is provided with a rotor 1B and a stator 1C, the rotor 1B rotates integrally with the shaft portion 1A, and the stator 1C is fixed to a motor case 1D. Similarly, the second motor 2 is provided with a rotor 2B that rotates integrally with the shaft portion 2A, and a stator 2C that is fixed to the motor case 2D, the rotor 2B being fixed to the shaft portion 2A. A magnet (not shown) is provided on the rotor 1B, and a coil (not shown) is provided on the stator 1C. Similarly, magnets (not shown) are provided on the rotor 2B, and coils (not shown) are provided on the stator 2C.

The first motor 1 and the second motor 2 are disposed facing each other in a posture in which both shaft portions 1A, 2A extend in the vehicle width direction while being spaced apart from each other. The shaft portions 1A and 2A are coaxially arranged so as to coincide with the rotation center C1. Further, a hole 4b is formed through each of the shaft portions 1A and 2A so as to communicate with the internal space 4a of each of the shaft portions 1A and 2A. Each hole 4b has a function of radially dispersing oil (described later) in the internal space 4a by centrifugal force accompanying rotation of the shaft portions 1A and 2A. The number, arrangement, and shape of the holes 4b are not particularly limited, but it is preferable that the oil be easily dispersed radially outward.

In the driving device 10 of the present embodiment, two sets of three shafts 11 to 13 are provided, each of which is arranged in parallel, and reduction gear trains for two-stage reduction are provided on the three shafts 11 to 13. Hereinafter, the three shafts 11 to 13 are referred to as a motor shaft (first shaft) 11, an intermediate shaft (second shaft) 12, and an output shaft (rotating shaft) 13 in this order from the upstream side of the power transmission path from each of the motors 1 and 2 to the left and right wheels. Two shafts 11 to 13 are provided. The two motor shafts 11, the two intermediate shafts 12, and the two output shafts 13 located on the left and right are configured in the same manner (bilaterally symmetrical). The reduction gear rows provided on the shafts 11 to 13 are also configured in the same manner in the left-right direction (in a left-right symmetrical manner).

The motor shaft 11 is a shaft to which power is first input, is formed in a hollow cylindrical shape having a rotation center C1, and is positioned coaxially with the shaft portions 1A and 2A of the left and right motors 1 and 2. The motor shaft 11 of the present embodiment is provided integrally with the shaft portions 1A, 2A, respectively, and the inner space of each motor shaft 11 is provided so as to communicate with the inner space 4a of each shaft portion 1A, 2A. The motor shafts 11 may be provided separately from the shaft portions 1A and 2A, and may be joined and coupled to each other. The motor gear (upstream gear) 31 is fixed (mounted) to the motor shaft 11. Each motor shaft 11 is positioned between the first motor 1 and the second motor 2, and is rotatably supported by two bearings (not shown) that are separated from each other.

The intermediate shaft 12 is formed in a hollow cylindrical shape having a rotation center C2, and is disposed parallel to the motor shaft 11. A first intermediate gear 32 that meshes with the motor gear 31 and a second intermediate gear 33 that is smaller in diameter (has a different diameter from the first intermediate gear 32) than the first intermediate gear 32 are fixed (attached) to the intermediate shaft 12. The left second intermediate gear 33 is disposed on the first motor 1 side (left side) of the left first intermediate gear 32, and the right second intermediate gear 33 is disposed on the second motor 2 side (right side) of the right first intermediate gear 32. That is, the first intermediate gear 32 having a large diameter is disposed on the inner side in the vehicle width direction than the second intermediate gear 33 having a small diameter. Further, it is preferable that the intermediate gears 32 and 33 are disposed close to each other. Further, the motor gear 31 and the first intermediate gear 32 constitute a first-stage reduction gear train.

Each intermediate shaft 12 is positioned between the first motor 1 and the second motor 2, and is rotatably supported by two bearings (not shown) spaced apart from each other. The intermediate shaft 12 is preferably disposed such that the first intermediate gear 32 is positioned radially inward of the outer circumferential surfaces 1f, 2f of the first motor 1 and the second motor 2 when viewed from the side. That is, it is preferable that the gears 32 and 33 on the intermediate shaft 12 completely overlap the motors 1 and 2 when viewed from the side of the vehicle.

The output shaft 13 is formed in a hollow cylindrical shape having a rotation center C3, and is disposed in parallel with the motor shaft 11. An output gear 34 that meshes with the second intermediate gear 33 is attached to the output shaft 13. The second reduction gear train of the second stage is constituted by the second intermediate gear 33 and the output gear 34. The gears 31 to 34 are located on power transmission paths from the left and right motors 1 and 2 to the left and right wheels. Specifically, the gears 31 to 34 of the three shafts 11 to 13 disposed on the left side among the two sets of shafts 11 to 13 are attached to the power transmission path of the first motor 1, and the gears 31 to 34 of the three shafts 11 to 13 disposed on the right side among the two sets of shafts 11 to 13 are attached to the power transmission path of the second motor 2.

As described above, the output gear 34 of the present embodiment transmits power between the first motor 1 and the second motor 2 and the left and right wheels, and the output gear 34 includes the output gear (first gear) 34L attached to the left side of the power transmission path of the first motor 1 and the output gear (second gear) 34R attached to the right side of the power transmission path of the second motor 2. Hereinafter, when the two output gears 34L and 34R are different from each other, the former is referred to as a left output gear 34L, and the latter is referred to as a right output gear 34R. The left output gear 34L and the right output gear 34R are disposed apart from each other in the vehicle width direction.

The output gear 34 of the present embodiment has a cylindrical portion 34b provided integrally with a tooth portion 34a having external teeth formed thereon, and the output gear 34 is attached to the output shaft 13 by slidably fitting the cylindrical portion 34b to a part of the outer peripheral surface of the output shaft 13. The output gear 34 is a gear having the largest diameter incorporated in the drive device 10. A tooth trace described later is formed on the tooth portion 34 a.

The output gear 34 of the present embodiment is supported so as to be rotatable in both directions around the output shaft 13. Hereinafter, the rotation direction (one direction) D of the output shaft 13 and the output gear 34 when the vehicle is moving forward is referred to as "normal rotation direction D". In addition, when the vehicle is retreated, the output shaft 13 and the output gear 34 rotate in the direction opposite to the normal rotation direction D. When viewed from the axial direction of the shafts 11 to 13 (the direction along the rotation centers C1, C2, and C3), the rotation direction of the motor shaft 11 and the rotation direction of the output shaft 13 are the same as each other, and are both directions opposite to the rotation direction of the intermediate shaft 12. Therefore, the rotation direction of the motor gear 31 and the rotation direction of the output gear 34 and the rotation directions of the intermediate gears 32, 33 are opposite to each other.

The gear mechanism 3 is disposed on one end side (inside in the vehicle width direction) of the output shaft 13, and one of the left and right wheels is disposed on the other end side (outside in the vehicle width direction) of the output shaft 13. That is, in the drive device 10, the left and right motors 1 and 2 are not disposed on the output shaft 13 provided with the left and right wheels, but are disposed offset from the output shaft 13. In fig. 2, the left and right wheels are not shown, and the joint portions 14 connected to the left and right wheels are shown.

The gear mechanism 3 of the present embodiment has a function of amplifying a torque difference at a predetermined amplification factor, and is configured by, for example, a differential mechanism, a planetary gear mechanism, and the like. The respective torques from the first motor 1 and the second motor 2 are input to an input element of the gear mechanism 3, and an output element of the gear mechanism 3 is provided so as to rotate integrally with the output shaft 13. The gear mechanism 3 includes a plurality of bearings, not shown.

The gear mechanism 3 of the present embodiment is located below the first motor 1 and the second motor 2, and is disposed between the left output gear 34L and the right output gear 34R. The cylindrical portion 34b externally fitted to the output shaft 13 is axially supported by two bearings (not shown) spaced apart from each other, so that each output shaft 13 is axially supported to be rotatable with respect to the housing 15. The joint portion 14 is an outer end portion of the output shaft 13 in the vehicle width direction, and is disposed on the outer side in the vehicle width direction than the respective end surfaces 1e, 2e of the first motor 1 and the second motor 2 on the outer side in the vehicle width direction. In other words, the length of the output shaft 13 is set such that the joint 14 is positioned outward in the vehicle width direction with respect to the end surfaces 1e, 2e of the motors 1, 2.

The housing 15 of the present embodiment is connected to each of the motor housings 1D and 2D, and houses the shafts 11 to 13, the gear mechanism 3, and the like. The housing 15 may be integrated, or may be formed by combining a plurality of members. The upper surface of the casing 15 is located on the rotation center C1 side of the upper surfaces of the outer peripheral surfaces 1f and 2f of the motor housings 1D and 2D. Thus, the drive device 10 is provided with a recess 16, and the recess 16 is located between the first motor 1 and the second motor 2 and at an upper portion of the housing 15. The recess 16 is a space formed above the motor shaft 11 between the left and right motors 1 and 2, and may be a recess formed in the housing 15.

[1-2. main part Structure ]

A circulation path 20 through which cooling and lubricating oil circulates is connected to the drive device 10 of the present embodiment. At least an oil pump 23 for pumping oil and an oil cooler 24 for cooling oil are attached to the circulation path 20. The oil pumped by the oil pump 23 is cooled by the oil cooler 24 and then supplied to the drive device 10.

The circulation passage 20 of the present embodiment includes at least a shaft center oil passage 22, and the shaft center oil passage 22 is a passage of oil sprayed radially from the shaft portions 1A and 2A of the motors 1 and 2. The axial oil path 22 is provided in each of the left and right motors 1 and 2.

The drive device 10 of the present embodiment is provided with an injection port 17 for injecting oil in the circulation path 20 into the motor housings 1D, 2D and the casing 15, a reservoir 18 for storing the oil, and a suction port 19 for sucking out the oil in the reservoir 18. That is, one end of the circulation passage 20 (one end of the axial oil passage 22) is connected to the injection port 17, and the other end is connected to the suction port 19.

The inlet ports 17 connected to the left and right axial oil passages 22 are disposed in the space between the two motor housings 1D and 2D (in the recess 16), and are provided in the protruding portions formed in the recess 16. The oil injected from one of the two injection ports 17 is guided to the first electric machine 1 side (left side), and the oil injected from the other is guided to the second electric machine 2 side (right side). In fig. 1, the case where two injection ports 17 are arranged in parallel in the direction orthogonal to the paper surface is exemplified, but the two injection ports 17 may be arranged in parallel in the vehicle width direction.

In the drive device 10 of the present embodiment, the oil injected from the injection port 17 flows toward the end surfaces 1e and 2e of the motors 1 and 2 through the inner spaces of the left and right motor shafts 11 and the inner spaces 4a of the shaft portions 1A and 2A. At this time, when the shaft portions 1A and 2A are rotating, the oil in the internal space 4a is dispersed radially through the holes 4b by the centrifugal force accompanying the rotation, and cools the coil and the magnet. The remaining part of the oil injected from the injection port 17 directly drops downward, and contributes to lubrication of bearings supporting the shafts 11 to 13, bearings in the gear mechanism 3, and the like.

The reservoir 18 is a container-shaped portion provided at a lower portion of the casing 15 and configured to store oil falling downward. The suction port 19 is provided in the reservoir 18. The oil in the reservoir 18 is sucked out of the reservoir 18 (the circulation path 20) from the suction port 19 by the action of the oil pump 23. The oil is then pumped by the oil pump 23 to the oil cooler 24, passes through the oil cooler 24, and is then injected into the motor cases 1D and 2D and the casing 15 through the injection port 17.

The height position of the oil level (liquid surface) of the oil stored in the reservoir 18 is highest when the oil is not circulating (when the oil pump 23 is not operating), and is lowest during the circulation of the oil (during the operation of the oil pump 23). Hereinafter, the position at which the oil level is the highest is referred to as "highest oil level H1", and the position at which the oil level is the lowest is referred to as "lowest oil level H2". As shown in fig. 2, in the present embodiment, the highest oil level H1 is set to be equal to or higher than the rotation center C3 of the output shaft 13, and the lowest oil level H2 is set to be at least above the suction port 19 and at a position where the output gear 34 is partially submerged. That is, the output gear 34 is disposed in a state in which a part thereof (a lower portion of the tooth portion 34 a) is immersed in the oil in the reservoir 18.

The output gear 34 is disposed offset from the suction port 19 in the axial direction of the output shaft 13 (the direction in which the rotation center C3 extends). The left output gear 34L and the right output gear 34R of the present embodiment are arranged to sandwich the suction port 19 and the gear mechanism 3 therebetween. In other words, the suction port 19 and the gear mechanism 3 are located between the left output gear 34L and the right output gear 34R (inside in the vehicle width direction). In the present embodiment, the case where the suction port 19 is provided at a substantially intermediate position between the left output gear 34L and the right output gear 34R in the axial direction of the output shaft 13 is exemplified.

The gears 31 to 34 are all helical gears (helical gears) having a helical tooth line. Therefore, the tooth trace of the gears 31 to 34 is inclined with respect to the rotation centers C1, C2 and C3 rather than being parallel to the rotation centers C1, C2 and C3. The direction of twisting of the tooth trace of the output gear 34 is set based on the normal rotation direction D and the arrangement of the suction port 19. The direction of the rotation of the tooth trace of the input gear 31 and the intermediate gears 32 and 33 is set according to the direction of the rotation of the tooth trace of the output gear 34.

Specifically, the tooth trace of the output gear 34 extends in the normal rotation direction D and in a direction away from the suction port 19. When the left output gear 34L is focused, the suction port 19 is positioned on the right side of the left output gear 34L, and therefore the tooth trace of the left output gear 34L extends leftward in the normal rotation direction D. Further, focusing on the right output gear 34R, the suction port 19 is positioned on the left side of the right output gear 34R, and therefore the tooth trace of the right output gear 34R extends rightward and in the normal rotation direction D.

In the example shown in fig. 2, the left output gear 34L is a so-called right twist (when the rotation axis is directed vertically, the tooth trace is a gear that rises to the right), and the right output gear 34R is a so-called left twist (when the rotation axis is directed vertically, the tooth trace is a gear that rises to the left). In this way, the left output gear 34L and the right output gear 34R are set such that the twisting directions of the tooth traces are opposite to each other. In the drive device 10 of the present embodiment, since the reduction gear train is configured to be bilaterally symmetrical, the magnitude of the helix angle of the left output gear 34L and the magnitude of the helix angle of the right output gear 34R are set to be the same.

The direction of the twist of the tooth trace of the second intermediate gear 33 is set to be opposite to that of the output gear 34 meshing with the second intermediate gear 33. Specifically, the tooth trace of the left second intermediate gear 33 extends in the opposite direction to the tooth trace of the left output gear 34L, and the tooth trace of the right second intermediate gear 33 extends in the opposite direction to the tooth trace of the right output gear 34R. The "opposite direction" as used herein means a twisting direction in which the tooth traces can mesh with each other. Specifically, the left second intermediate gear 33 is left-twisted so as to be capable of meshing with the right twisted left output gear 34L, and the right second intermediate gear 33 is right-twisted so as to be capable of meshing with the left twisted right output gear 34R.

The first intermediate gear 32 and the second intermediate gear 33 provided on the same intermediate shaft 12 have the same tooth trace twisting direction. Focusing on the left intermediate shaft 12, the respective tooth lines of the first intermediate gear 32 and the second intermediate gear 33 attached to the intermediate shaft 12 extend in the opposite direction to the tooth line of the left output gear 34L. That is, the first intermediate gear 32 and the second intermediate gear 33 (on the left side) are both set to the left twist. When attention is paid to the right intermediate shaft 12, the respective tooth traces of the first intermediate gear 32 and the second intermediate gear 33 attached to the intermediate shaft 12 extend in the opposite direction to the tooth trace of the right output gear 34R. That is, these (right) first intermediate gear 32 and second intermediate gear 33 are both set to right twist.

The direction of twisting of the tooth trace of the input gear 31 is set to be opposite to that of the first intermediate gear 32 meshing with the input gear 31. Specifically, the tooth trace of the left input gear 31 extends in the opposite direction to the tooth trace of the left first intermediate gear 32, and the tooth trace of the right input gear 31 extends in the opposite direction to the tooth trace of the right first intermediate gear 32. In the example shown in fig. 2, the left input gear 31 is twisted right, and the right input gear 31 is twisted left.

[2. Effect ]

In the case where the vehicle advances, the respective input shafts 11 rotate due to the power of the first motor 1 and the second motor 2. As a result, each input gear 31 rotates, and power is transmitted from the input gear 31 to the first intermediate gear 32, whereby each intermediate shaft 12 rotates. Further, as the intermediate shaft 12 rotates, power is transmitted from the second intermediate gear 33 to the output gears 34, and the output gears 34 rotate in the normal rotation direction D.

As described above, the output gear 34 is disposed in a state of being partially immersed in the oil in the reservoir 18, and therefore, the oil enters a part of the tooth trace of the output gear 34. This oil is entrained with the rotation of the output gear 34. When the output gear 34 rotates in the normal rotation direction D, the tooth lines of the output gear 34 extend in the above-described direction, and the oil entering the tooth lines is thereby carried up toward the suction port 19 (see the broken-line arrow in fig. 2). In the present embodiment, the left output gear 34L lifts oil to the right, and the right output gear 34R lifts oil to the left.

Therefore, in the reservoir 18, the oil is guided from each output gear 34 to the suction port 19 and the gear mechanism 3. By collecting the oil in the suction port 19 in this way, the oil is easily sucked out from the suction port 19. Therefore, the oil circulation performance in the circulation passage 20 is improved, and the oil level in the reservoir 18 is easily maintained higher than the minimum oil level H2. In addition, by guiding the oil to the gear mechanism 3, cooling and lubrication of the gear mechanism 3 are promoted.

Further, since the gears 31 to 34 are all helical gears, force can be transmitted smoothly as compared with a normal flat gear (spur gear), but on the other hand, an axial force (thrust force) generated by a helix angle of a tooth trace may become large. In contrast, in the counter shaft 12, since the twisting direction of the tooth trace of the first counter gear 32 that transmits power from the motor gear 31 and the twisting direction of the tooth trace of the second counter gear 33 that transmits power to the output gear 34 are equal to each other, the axial force F1 of the first counter gear 32 and the axial force F2 of the second counter gear 33 act in opposite directions to each other. For example, as shown in fig. 2, when the vehicle advances with the power of the first motor 1 and the second motor 2, the axial force F1 of the first intermediate gear 32 acts inward in the vehicle width direction, while the axial force F2 of the second intermediate gear 33 acts outward in the vehicle width direction. Thereby, the total axial force in the intermediate shaft 12 is reduced.

[3. Effect ]

(1) According to the drive device 10 described above, when the output gear 34 rotates in the normal rotation direction D, the oil in the reservoir 18 is drawn up toward the suction port 19 through the tooth trace of the output gear 34, and therefore, the oil can be collected in the suction port 19. This suppresses air from entering the suction port 19 even if the oil level in the reservoir 18 fluctuates or inclines, and therefore, the oil suction performance in the casing 15 can be improved.

In particular, when the oil sucked out from the suction port 19 is supplied again into the casing 15 (oil circulation), the oil circulation can be improved by improving the suction performance as described above. Therefore, the lubrication performance and cooling performance of the oil with respect to the parts can be improved, and the reduction of the oil level in the reservoir 18 can be suppressed.

Further, by positioning the suction port 19 between the two output gears 34 provided in the drive device 10, oil can be taken up from each of the two output gears 34 to the suction port 19 side. Therefore, more oil can be collected in the suction port 19. This can improve the performance of the drive device 10.

(2) The left output gear 34L is mounted on the power transmission path of the first motor 1, and the right output gear 34R is mounted on the power transmission path of the second motor 2. By disposing the output gear 34 on each power transmission path of the two motors 1 and 2 that drive the left and right wheels of the vehicle in this manner, oil can be taken up from each of the output gears 34 to the suction port 19 side by the power of each of the motors 1 and 2.

(3) Further, since the output gears 34 (the left output gear 34L and the right output gear 34R) are disposed so as to sandwich the gear mechanism 3 for distributing torque to the left and right wheels therebetween, oil can be taken up from each of the left and right output gears 34 to the gear mechanism 3 side. Therefore, cooling and lubrication of the gear mechanism 3 provided in the drive device 10 can be promoted. This can further improve the performance of the drive device 10.

(4) Since the frequency of forward movement of the vehicle is higher than the frequency of backward movement, the output gear 34 is set in the direction of twisting of the tooth trace so as to lift the oil toward the suction port 19 when the vehicle is moving forward (the tooth trace extends in the normal rotation direction D and in the direction away from the suction port 19), whereby the oil can be collected to the suction port 19 at a high frequency.

(5) Since the first intermediate gear 32 and the second intermediate gear 33 attached to the one intermediate shaft 12 each have a helical tooth trace extending in a direction opposite to the tooth trace of the output gear 34 meshing with the second intermediate gear 33, the axial force F1 of the first intermediate gear 32 and the axial force F2 of the second intermediate gear 33 can be caused to act in directions opposite to each other. This can reduce the total axial force in the intermediate shaft 12. Therefore, the axial position accuracy of the first intermediate gear 32 and the second intermediate gear 33 can be improved.

[4. modification ]

The arrangement of the output gear 34 exemplified in the above embodiments is an example. The output gear 34 may be arranged to be offset from the suction port 19 at least in the axial direction of the output shaft 13 and to have a tooth line extending in the above-described direction, and may not be arranged to sandwich the gear mechanism 3 between the output gears 34. Even when the output gears 34 are not disposed so as to sandwich the gear mechanism 3 therebetween, the oil in the reservoir 18 is drawn up toward the suction port 19 by the output gears 34, and thereby the oil suction performance in the casing 15 can be improved as described above.

Since the oil is more easily taken up as the helix angle of the tooth trace of the output gear 34 is larger, it is preferable to set the helix angle of the tooth trace to be larger in terms of collecting the oil to the suction port 19. However, since the axial force tends to increase as the helix angle of the helical gear increases, the specific helix angle of the tooth trace of the output gear 34 is preferably set in consideration of the magnitude of the axial force allowed by the output shaft 13.

The output gear 34 may be rotatable in at least one direction of the output shaft 13, and may be configured to be rotatable only in the normal rotation direction D. In the drive device 10, as described above, the structure of the gear that lifts oil toward the suction port 19 may be applied to a gear other than the output gear 34.

The configuration of the driving device 10 described above is an example. The diameters of the two intermediate gears 32 and 33 attached to the intermediate shaft 12 may be different from each other, and for example, a speed increasing gear train may be configured by using a second intermediate gear having a larger diameter than the first intermediate gear 32. In this case, the twisting direction of each tooth trace is set so that the tooth traces of the two intermediate gears attached to the intermediate shaft 12 extend in the opposite direction to the tooth trace of the output gear, whereby the total axial force of the intermediate shaft can be reduced as described above.

The configuration of the circulation path 20 described above is also an example. The circulation path 20 may be provided with a direct oil path as a path for directly supplying (dropping) oil to the coils of the motors 1 and 2, in addition to the axial oil path 22. In addition, a path through which oil flows in the drive device 10 is also an example. The oil path may be set so that at least the oil is accumulated in the reservoir 18 of the casing 15.

Description of the symbols

1 first electric machine

1A shaft part

2 second electric machine

2A shaft part

3 Gear mechanism

10 drive device (left and right wheel drive device)

11 Motor shaft (first shaft)

12 middle shaft (second shaft)

13 output shaft (rotating shaft)

15 casing

18 reservoir

19 suction port

31 electric motor gear (upstream gear)

32 first intermediate gear

33 second intermediate gear

34 output gear (Gear)

34L left output gear (first gear)

34R Right output gear (second gear)

D forward direction (one direction).