JP2021134902A - Lubrication structure of power transmission device - Google Patents

Abstract

To provide lubrication structure of a power transmission device enabling structure of a reduction gear (power transmission device) to be simplified and the reduction gear to be downsized by simplifying a lubrication passage.SOLUTION: Lubrication structure of a reduction gear T is provided in which a first planetary gear mechanism PG1 and a second planetary gear mechanism PG2 are arranged in parallel with each other in an axial direction, and rotation of an input shaft 2 is decelerated by the first planetary gear mechanism PG1 and the second planetary gear mechanism PG2 and transmitted to output shafts 5L, 5R. The lubrication structure of the reduction gear T has constitution in which an axial first oil passage 10 opened, at one end, toward the second planetary gear mechanism PG2 is formed in a first pinion shaft 8 of the first planetary gear mechanism PG1, an axial second oil passage 13 opened, at one end, toward the first planetary gear mechanism PG1 is formed in a second pinion shaft 12 of the second planetary gear mechanism PG2, lubricating oil supplied to the first oil passage 10 is delivered to the second oil passage 13, and the first planetary gear mechanism PG1 and the second planetary gear mechanism PG2 are lubricated respectively by the lubricating oil flowing in the first oil passage 10 and the second oil passage 13.SELECTED DRAWING: Figure 3

Description

The present invention relates to a lubrication structure of a power transmission device that reduces the rotation of an input shaft by a multi-stage planetary gear mechanism and transmits the rotation to the output shaft.

For example, in a vehicle that decelerates the rotation of a drive source such as an engine or an electric motor and transmits it to an axle that is an output shaft to travel, a speed reducer that is a power transmission device is provided in a power transmission path. In order to obtain a high reduction ratio in an engine, for example, a reduction gear in which two planetary gear mechanisms are arranged side by side in the axial direction has been proposed (see, for example, Patent Document 1).

In such a speed reducer, each planetary gear mechanism revolves around the sun gear, a ring gear arranged around the sun gear, and a plurality of pinion gears (planetary gears) that revolve around the sun gear while engaging with the sun gear and the ring gear. ) And a carrier that rotatably supports these pinion gears. According to a speed reducer in which two such planetary gear mechanisms are arranged side by side in the axial direction, for example, the rotation of the input shaft rotationally driven by the drive source is reduced in two stages by the two planetary gear mechanisms. Therefore, a high reduction ratio can be obtained, and the whole can be made compact.

By the way, in a speed reducer configured by arranging two planetary gear mechanisms side by side in the axial direction, it is necessary to lubricate each planetary gear mechanism with lubricating oil, but conventionally, the lubricating oil supply path from the oil pump is set to 2. A configuration is adopted in which each planetary gear mechanism is lubricated by the lubricating oil that is divided into systems and flows along each system.

Japanese Unexamined Patent Publication No. 2015-105721

However, as the lubrication structure of the speed reducer, if the supply path of the lubricating oil from the oil pump is divided into two systems and each planetary gear mechanism is lubricated by the lubricating oil flowing along each system as in the conventional case, There is a problem that the lubrication path becomes complicated and the configuration of the speed reducer becomes complicated, resulting in an increase in size.

The present invention has been made in view of the above problems, and an object of the present invention is to lubricate a power transmission device capable of simplifying and downsizing the structure of a speed reducer (power transmission device) by simplifying the lubrication path. To provide the structure.

In order to achieve the above object, in the present invention, the first planetary gear mechanism (PG1) and the second planetary gear mechanism (PG2) are arranged side by side along the axial directions of the input shaft (2) and the output shaft (5L, 5R). Then, the rotation of the input shaft (2) is decelerated by the first planetary gear mechanism (PG1) and the second planetary gear mechanism (PG2) and transmitted to the output shafts (5L, 5R). The first oil in the axial direction having a lubrication structure of T), one end of which opens toward the first pinion shaft (8) of the first planetary gear mechanism (PG1) toward the second planetary gear mechanism (PG2). An axial second oil passage that forms a path (10) and one end opens toward the first planetary gear mechanism (PG1) in the second pinion shaft (12) of the second planetary gear mechanism (PG2). (13) is formed, and the lubricating oil supplied to the first oil passage (10) is transferred from the first oil passage (10) to the second oil passage (13), and these first oil passages are passed. It is characterized in that the first planetary gear mechanism (PG1) and the second planetary gear mechanism (PG2) are lubricated by the lubricating oil flowing through the second oil passage (13) and (10), respectively.

According to the present invention, the lubricating oil supplied to the first oil passage is transferred from the first oil passage to the second oil passage, and the lubricating oil flowing through the first oil passage and the second oil passage causes the first planet. Since the gear mechanism and the second planetary gear mechanism are lubricated respectively, only one system is required to supply lubricating oil to the first planetary gear mechanism and the second planetary gear mechanism, and the lubrication path is simplified to simplify the lubrication path of the power transmission device. The structure can be simplified and miniaturized.

In the lubrication structure, it is desirable that the open end of the first oil passage (10) protrudes toward the second planetary gear mechanism (PG2). In this case, a sleeve (11) protruding toward the second planetary gear mechanism (PG2) may be press-fitted into the open end of the first oil passage (10).

By projecting the open end of the first oil passage toward the second planetary gear mechanism as described above, the lubricating oil can be smoothly delivered from the first oil passage to the second oil passage.

Further, in the lubricating structure, the open end of the first oil passage (10) is covered from the outer peripheral side, and the lubricating oil flowing out from the open end of the first oil passage (10) is received and used as the second oil passage. It is desirable to provide an oil receiver (14) that leads to (13). In this case, it is more desirable that the oil receiver (14) and the sleeve (11) overlap each other in the axial direction.

According to the above configuration, the lubricating oil flowing out from the first oil passage can be efficiently received by the oil receiver and reliably delivered to the second oil passage.

Further, in the lubrication structure, it is desirable that the second oil passage (13) is arranged radially outward from the first oil passage (10).

As described above, by arranging the second oil passage radially outward from the first oil passage, the lubricating oil that flows out from the first oil passage and goes outward in the radial direction by centrifugal force is first. It can be reliably delivered to the second oil passage arranged radially outside the oil passage.

According to the present invention, since only one system is required to supply lubricating oil to the first planetary gear mechanism and the second planetary gear mechanism, the lubrication path is simplified to simplify the structure and miniaturize the power transmission device. The effect of being able to do is obtained.

It is a schematic cross-sectional view of the electric unit provided with the lubrication structure of the speed reducer (power transmission device) which concerns on this invention. It is a speed diagram of a speed reducer. It is a half-cut cross-sectional view of the reduction gear main part provided with the lubrication structure which concerns on this invention. It is an enlarged detailed view of part A of FIG.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[Composition of electric unit]
FIG. 1 is a schematic cross-sectional view of an electric unit provided with a lubrication structure for a speed reducer (power transmission device), FIG. 2 is a speed diagram of the speed reducer, and the electric unit U shown in FIG. 1 is an electric vehicle (not shown). It is installed in an EV vehicle) and has the following configuration.

That is, the electric unit U shown in FIG. 1 includes an electric motor M as a drive source, a multi-stage speed reducer T, a differential mechanism (differential mechanism) D, and the like in the case 1. More specifically, the inside of the case 1 is divided into a motor chamber SM and a gear chamber SG by a partition wall 1A, an electric motor M which is a drive source is housed in the motor chamber SM, and a speed reducer is housed in the gear chamber SG. (Power transmission device) T and differential mechanism D are housed. The electric motor M also functions as a generator during regeneration, and a battery is electrically connected to the electric motor M via an inverter (not shown), and the electric power supplied from the battery is connected to the electric motor M. The electric motor M is driven to rotate.

A rotatable hollow input shaft (motor shaft) 2 rotationally driven by the electric motor M is inserted in the center of the electric motor M, and both ends of the input shaft 2 in the axial direction are bearings (balls). It is rotatably supported by the case 1 by the bearing) 3. An axial end portion (left end portion in FIG. 1) of the input shaft 2 penetrates the partition wall 1A of the case 1 and faces the gear chamber SG.

The speed reducer T housed in the gear chamber SG includes a first planetary gear mechanism PG1 and a second planetary gear mechanism PG2 arranged side by side adjacent to the axial direction of the input shaft 2 (the left-right direction in FIG. 1). .. Here, the first planetary gear mechanism PG1 includes a small-diameter sun gear s1 formed on the outer periphery of one end in the axial direction (left end in FIG. 1) extending to the gear chamber SG of the input shaft 2, and inside the case 1. A large-diameter ring gear r1 fixed to the circumference and a plurality of pinion gears (planetary gears) p1 that revolve around the sun gear s1 while engaging with the sun gear s1 and the ring gear r1 and revolving around the sun gear s1. , The carrier c1 that supports these pinion gears p1 so as to be rotatable (rotating) is provided.

The second planetary gear mechanism PG2 includes a small-diameter sun gear s2 formed on the carrier c1 of the first planetary gear mechanism PG1, a large-diameter ring gear r2 fixed to the inner circumference of the case 1, and a sun gear s2 and a ring gear r2. A plurality of pinion gears (planetary gears) p2 that revolve around the sun gear s2 while meshing with each other (only two are shown in FIG. 1) and a carrier c2 that supports these pinion gears p2 so that they can rotate (rotate). I have.

A case (diff case) 4 of the differential mechanism D is attached to the carrier c2 of the second planetary gear mechanism PG2. Since the configuration of the differential mechanism D is known, the description thereof will be omitted, but from this differential mechanism D, the left and right output shafts (axles) 5L and 5R are on the same axis in the vehicle width direction (FIG. 1). It extends along the left-right direction), and wheels (driving wheels) (not shown) are attached to the outer ends of the axles 5L and 5R, respectively. Here, the case (diff case) 4 of the differential mechanism D is rotatably supported by the case 1 by the bearing (ball bearing) 6.

By the way, one output shaft (axle) 5R (on the right side of FIG. 1) penetrates the hollow portion of the carrier c2 of the second planetary gear mechanism PG2 and the hollow input shaft (motor shaft) 2 to the outside of the case 1. The output shaft (axle) 5R and the input shaft (motor shaft) 2 are rotatably arranged along the same axis along the vehicle width direction (left-right direction in FIG. 1). An axial end portion (right end portion in FIG. 1) of the output shaft (axle) 5R is rotatably supported by the case 1 by a bearing (ball bearing) 7.

Thus, in the electric unit U configured as described above, when the electric motor M is started and the input shaft (motor shaft) 2 is rotationally driven at a predetermined speed, the rotation of the input shaft 2 becomes the first. It is decelerated by two stages by the 1st planetary gear mechanism PG1 and the 2nd planetary gear mechanism PG2 and transmitted to the left and right output shafts (axles) 5L and 5R.

That is, as shown in FIG. 2, in the first planetary gear mechanism PG1, when the sun gear s1 formed on the input shaft (motor shaft) 2 is rotationally driven together with the input shaft 2 at a speed V1, the sun gear s1 rotates while rotating. The carrier c1 that supports the pinion gear p1 that revolves around the pinion gear p1 rotates at a speed (revolution speed of the pinion gear p1) V2 (<V1). As a result, the rotation of the input shaft (motor shaft) 2 is decelerated from the speed V1 to the speed V2 (<V1) by the first planetary gear mechanism PG1.

Then, in the second planetary gear mechanism PG2, as shown in FIG. 2, the sun gear s2 formed on the carrier c1 of the first planetary gear mechanism PG1 rotates at the same speed V2 as the carrier c1 and rotates while rotating on the sun gear s2. The carrier c2 that supports the pinion gear p2 that revolves around it rotates at a speed (revolution speed of the pinion gear p2) V3 (<V2).

As a result of the above, the rotation of the input shaft (motor shaft) 2 is decelerated from the speed V1 to the speed V3 (<V2 <V1) by the first planetary gear mechanism PG1 and the second planetary gear mechanism PG2. Then, the case (diff case) 4 of the differential mechanism D rotates at a speed V3 together with the carrier c2 of the second planetary gear mechanism PG2, and this rotation is distributed by the differential mechanism D to the left and right output shafts (axles) 5L and 5R. And the left and right output shafts (axles) 5L and 5R are rotationally driven, respectively. As a result, the left and right wheels (driving wheels) attached to the outer ends of the left and right output shafts (axles) 5L and 5R are rotationally driven, so that the electric vehicle (EV vehicle) has a predetermined speed. Drive on.

[Lubrication structure of reducer]
Next, the lubrication structure of the speed reducer T according to the present invention will be described below with reference to FIGS. 3 and 4.

FIG. 3 is a half-cut cross-sectional view of a reduction gear main part having a lubrication structure according to the present invention, and FIG. 4 is an enlarged detailed view of part A of FIG. 3. As shown in FIG. 3, in the first planetary gear mechanism PG1, A plurality of pinion gears p1 (only one is shown in FIG. 3) are rotatably (rotated) supported by bearings (needle bearings) 9 with respect to the horizontal first pinion shaft 8 attached to the carrier c1. .. A first oil passage 10 extending in the axial direction is formed at the axial center of each first pinion shaft 8 (only one is shown in FIG. 3), and one end in the axial direction of each first oil passage 10. (Left end in FIG. 3) opens toward the second planetary gear mechanism PG2.

Here, a cylindrical sleeve 11 is press-fitted into the open end (open end portion) of the first oil passage 10 formed in each of the first pinion shafts 8, and the sleeve 11 is the first oil passage. It protrudes from 10 toward the end surface of the second pinion shaft 12 of the second planetary gear mechanism PG2 by a predetermined amount. In the present embodiment, the sleeve 11 which is a member different from the first pinion shaft 8 is press-fitted into the open end of the first oil passage 10, but the first oil of the first pinion shaft 8 is replaced with the sleeve 11. Cylindrical protrusions may be integrally projected on the peripheral edge of the open end of the road 10. Here, the second pinion shaft 12 of the second planetary gear mechanism PG2 supports each of the plurality of pinion gears p2 so as to be rotatable (rotating).

Further, a second oil passage 13 extending in the axial direction is formed at a position eccentric from the axial center of each of the second pinion shafts 12 (only one is shown in FIG. 3) of the second planetary gear mechanism PG2. , One end of each second oil passage 13 in the axial direction (right end in FIG. 3) is open toward the first planetary gear mechanism PG1. Here, as shown in FIG. 3, the second oil passage 13 formed in each of the second pinion shafts 12 is arranged radially outward from the first oil passage 10 formed in each of the first pinion shafts 8. Has been done.

Then, on the end surface (right end surface of FIG. 3) of the carrier c2 of the second planetary gear mechanism PG2 facing the carrier c1 of the first planetary gear mechanism PG1, a sleeve 11 protruding from the open end of the second oil passage 13 is placed on the outer circumference. A ring plate-shaped oil receiver 14 that covers from the side is attached. The oil receiver 14 has a function of receiving the lubricating oil flowing out from the sleeve 11 press-fitted into the opening end of the first oil passage 10 and guiding the lubricating oil to the second oil passage 13 as follows. It is configured.

That is, as shown in detail in FIG. 4, the portion of the oil receiver 14 arranged in the axial gap between the carrier c1 and the carrier c2 is in the radial direction from the end face of the carrier c2 toward the end face of the carrier c1. It is provided with an inclined portion 14a that inclines while expanding inward at an angle of approximately 45 °, and a guide portion 14b that extends vertically inward in the radial direction (lower part of FIG. 4) from the inner edge of the inclined portion 14a. There is. Then, in the axial gap between the carrier c1 and the carrier c2, the inclined portion 14a and the guide portion 14b of the oil receiver 14 and the sleeve 11 overlap each other in the axial direction.

By the way, as shown in FIG. 3, an oil passage 15 is formed at the center of the output shaft (axle) 5R on one side (right side), and this oil passage 15 is an auxiliary machine, which is an oil pump (not shown). It is connected to the discharge side of. A plurality of circular oil holes 16 (only one is shown in FIG. 3) communicating with the oil passage 15 are formed in the output shaft (axle) 5R in the radial direction. Is open in a cylindrical oil passage 17 formed between an input shaft (motor shaft) 2 and an output shaft (axle) 5R.

Further, a plurality of circular oil holes 18 (only one is shown in FIG. 3) are formed in the input shaft (motor shaft) 2, and between the carrier c1 and the input shaft (motor shaft) 2. The cylindrical oil passage 19 and the oil passage 17 formed in the above are communicated with each other through an oil hole 18. The carrier c1 and the first pinion shaft 8 are formed with radial oil passages 20 and 21 communicating with each other, and the first oil passage 10 formed on the first pinion shaft 8 is a radial oil passage. It communicates with the oil passage 19 via 20 and 21, and also communicates with a bearing (needle bearing) 9 via a radial oil passage 22 formed in the first pinion shaft 8.

Further, the second oil passage 13 formed in the second pinion shaft 12 communicates with the double bearing (needle bearing) 24 via the radial oil passage 23 formed in the second pinion shaft 12. Each pinion gear p2 of the second planetary gear mechanism PG2 is rotatably (rotated) supported by a carrier c2 by a double bearing (needle bearing) 24.

In the lubrication structure of the first planetary gear mechanism PG1 and the second planetary gear mechanism PG2 configured as described above, when lubricating oil is supplied from an oil pump (not shown) to the oil passage 15 of the output shaft (axle) 5R. , As shown by the arrow in FIG. 3, this lubricating oil flows from the oil hole 16 through the oil passage 17 and the oil hole 18 into the oil passage 19. Then, the lubricating oil that has flowed into the oil passage 19 flows into the first oil passage 10 of the first pinion shaft 8 from the radial oil passages 20 and 21 formed in the carrier c1 and the first pinion shaft 8, respectively, and the lubricating oil flows into the first oil passage 10 of the first pinion shaft 8. A part is supplied from the radial oil passage 22 to the bearing (needle bearing) 9 to lubricate the bearing (needle bearing) 9, and is supplied to the meshing portion between the pinion gear p1 and the ring gear r1 to provide the meshing portion. Lubricate.

Further, the other part of the lubricating oil that has flowed into the first oil passage 10 of the first pinion shaft 8 is the shaft of the carrier c1 and the carrier c2 from the sleeve 11 press-fitted into the opening end of the first oil passage 10. The lubricating oil flows out into the directional gap, but the lubricating oil that flows out moves outward in the radial direction (above in FIGS. 3 and 4) due to the centrifugal force accompanying the rotation of the first pinion shaft 8, and the guide portion of the oil receiver 14 Guided by 14b and received by the oil receiver 14. Then, the lubricating oil received by the oil receiver 14 collides with the inclined portion 14a inclined by approximately 45 ° of the oil receiver 14, the flow direction thereof is bent at a right angle and changed to the axial direction, and the second pinion shaft is used. It is introduced into the second oil passage 13 formed in 12. That is, the lubricating oil flowing out of the first oil passage 10 is delivered to the second oil passage 13 by the oil receiver 14.

The lubricating oil delivered to the second oil passage 13 as described above is supplied to the bearing (needle bearing) 24 from the radial oil passage 23 formed in the second pinion shaft 12, and the bearing (needle bearing). ) 14 is lubricated, and the meshing portion is supplied to the meshing portion between the pinion gear p2 and the ring gear r2 to lubricate the meshing portion.

As described above, in the lubricating structure according to the present embodiment, the lubricating oil supplied to the first oil passage 10 is delivered from the first oil passage 10 to the second oil passage 13, and these first oil passages are used. Lubricating oil for the first planetary gear mechanism PG1 and the second planetary gear mechanism PG2 because the first planetary gear mechanism PG1 and the second planetary gear mechanism PG2 are lubricated by the lubricating oil flowing through the 10 and the second oil passage 13, respectively. Only one supply system is required, and the lubrication path can be simplified to simplify the structure and miniaturize the speed reducer T.

Further, in the present embodiment, since the sleeve 11 protruding toward the second planetary speed reduction mechanism PG2 is press-fitted into the open end of the first oil passage 10, the lubricating oil from the first oil passage 10 to the second oil passage 13 is supplied. Can be delivered smoothly. Then, in the present embodiment, an oil receiver 14 that covers the open end of the sleeve 11 from the outer peripheral side is provided so that the oil receiver 14 and the sleeve 11 overlap in the axial direction, so that the oil receiver 14 and the sleeve 11 flow out from the first oil passage 10. The lubricating oil to be used can be efficiently received by the oil receiver 14 and reliably delivered to the second oil passage 13.

Then, in the present embodiment, since the second oil passage 13 is arranged radially outward from the first oil passage 10, lubrication that flows out from the first oil passage 10 and is directed outward in the radial direction by centrifugal force. The oil can be reliably delivered to the second oil passage 13 arranged radially outside the first oil passage 10.

Although the embodiment in which the present invention is applied to the lubrication structure of the speed reducer mounted on the electric vehicle (EV vehicle) has been described above, the lubrication structure according to the present invention includes a vehicle having only an engine as a drive source and a vehicle. The same applies to the lubrication structure of a speed reducer mounted on a hybrid vehicle (HEV vehicle) in which an engine and an electric motor are used as a drive source, or a speed reducer provided in any device other than the vehicle.

In addition, the present invention is not limited to the embodiments described above, and various modifications can be made within the scope of claims and the technical ideas described in the specification and drawings.

1 Case 2 Input shaft (motor shaft)
5L, 5R output shaft (axle)
8 1st pinion shaft 10 1st oil passage 11 Sleeve 12 2nd pinion shaft 13 2nd oil passage 14 Oil receiver PG1 1st planetary gear mechanism PG2 2nd planetary gear mechanism T reducer (power transmission device)

Claims (7)

The first planetary gear mechanism and the second planetary gear mechanism are arranged side by side along the axial directions of the input shaft and the output shaft, and the rotation of the input shaft is decelerated by the first planetary gear mechanism and the second planetary gear mechanism. It is a lubrication structure of a power transmission device that transmits to the output shaft.
An axial first oil passage having one end opening toward the second planetary gear mechanism is formed on the first pinion shaft of the first planetary gear mechanism.
An axial second oil passage having one end opening toward the first planetary gear mechanism is formed on the second pinion shaft of the second planetary gear mechanism.
The lubricating oil supplied to the first oil passage is transferred from the first oil passage to the second oil passage, and the lubricating oil flowing through the first oil passage and the second oil passage causes the first planetary gear. A lubrication structure for a power transmission device, which lubricates the mechanism and the second planetary gear mechanism, respectively. The lubrication structure for a power transmission device according to claim 1, wherein the open end of the first oil passage is projected toward the second planetary gear mechanism. The lubrication structure for a power transmission device according to claim 2, wherein a sleeve projecting toward the second planetary gear mechanism is press-fitted into the open end of the first oil passage. An oil receiver is provided which covers the open end of the first oil passage from the outer peripheral side, receives the lubricating oil flowing out from the open end of the first oil passage, and guides the lubricating oil to the second oil passage. The lubrication structure for the power transmission device according to claim 3. The lubrication structure for a power transmission device according to claim 4, wherein the oil receiver and the sleeve are overlapped with each other in the axial direction. An oil receiver is provided which covers the open end of the first oil passage from the outer peripheral side, receives the lubricating oil flowing out from the open end of the first oil passage, and guides the lubricating oil to the second oil passage. The lubrication structure for the power transmission device according to claim 1 or 2. The lubrication structure for a power transmission device according to any one of claims 1 to 6, wherein the second oil passage is arranged outside the first oil passage in the radial direction.

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