Power transmission device

Abstract

[Problem] To improve the stirring resistance of an axle in an oil reservoir. [Solution] A power transmission device comprises: a case having, at a bottom part thereof, an oil reservoir; and a first axle, a second axle, and a third axle which are axially supported by the case. The first axle has a first gear part which is connected to a power source, and which outputs power from the power source. The second axle has a second gear part into which power from the first gear part is input, and which outputs the power that was input. The third axle has a third gear part into which power from the second gear part is input, and which is at least partially immersed in the oil reservoir. The case comprises: an air breather chamber that separates air and oil within the case, and that communicates with the atmosphere; an oil catch tank that stores oil scraped up by the third gear part; and an oil guide that introduces the oil scraped up by the third gear part into the oil catch tank. The air breather chamber is provided above and near the third axle. The oil catch tank is provided above and near the first axle. The oil guide is provided above the second axle. The second axle is disposed within the case on the outside of the oil reservoir.

Description

Technical Field

[0001] The present invention relates to a power transmission device.

Background Art

[0002] Patent Document 1 discloses a cooling structure of a motor in which a countershaft is disposed in an oil sump.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In addition to the oil sump at the lower part of the case, the power transmission device may have an air breather chamber and an oil catch tank inside the case. The air breather chamber separates air and oil inside the case and communicates with the atmosphere. The oil catch tank stores the oil scraped up by the gear portion of the shaft immersed in the oil sump. The oil catch tank is used, for example, to lower the oil level in the oil sump during device operation. If the oil level decreases, the stirring resistance of the shaft immersed in the oil sump decreases, so the power transmission efficiency of the device improves.

[0005] However, the air breather chamber and the oil catch tank may restrict the arrangement of the shafts of the power transmission device. For this reason, depending on the arrangement of the air breather chamber and the oil catch tank, it may result in an arrangement in which shafts that do not necessarily need to be immersed in the oil sump have to be immersed in the oil sump, and there is a risk that the stirring resistance will increase.

[0006] The present invention has been made in view of such problems, and an object thereof is to improve the stirring resistance of the shaft in the oil sump.

Means for Solving the Problems

[0007] A power transmission device according to an aspect of the present invention includes a case having an oil sump at a lower portion thereof, and a first shaft, a second shaft, and a third shaft that are supported by the case in an axial direction. The first shaft is connected to a power source and has a first gear portion that outputs power from the power source. The second shaft has a second gear portion to which power is input from the first gear portion and that outputs the input power. The third shaft has a third gear portion to which power is input from the second gear portion and at least a part of which is immersed in the oil sump. The case has an air breather chamber that separates air and oil in the case and communicates with the atmosphere, an oil catch tank that stores oil scraped up by the third gear portion, and an oil guide that guides the oil scraped up by the third gear portion to the oil catch tank. The air breather chamber is provided above and in the vicinity of the third shaft. The oil catch tank is provided above and in the vicinity of the first shaft. The oil guide is provided above the second shaft. The second shaft is disposed outside the oil sump in the case.

Effect of the Invention

[0008] According to this aspect, when power is transmitted from the first shaft to the third shaft via the second shaft, the air breather chamber is provided above and in the vicinity of the third shaft, and the oil catch tank is provided above and in the vicinity of the first shaft. Then, the oil scraped up by the third gear portion is introduced into the oil catch tank by the oil guide provided above the second shaft. As a result, it becomes possible to provide the second shaft in the upper space in the case between the first shaft and the third shaft, and the second shaft is disposed outside the oil sump. Consequently, compared with a case where the second shaft is disposed so as to be immersed in the oil sump, the stirring resistance of the shaft can be reduced, and the stirring resistance of the shaft in the oil sump can be improved.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Best Mode for Carrying Out the Invention

[0010] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0011] FIG. 1 is a schematic configuration diagram of a power transmission device 100 according to the present embodiment. In FIG. 1, the rotary electric machine 40 is shown by a two-dot chain line. As shown in FIG. 1, the power transmission device 100 includes a case 10, a speed reduction mechanism 20, and a differential gear 30. The power transmission device 100 is mounted on a vehicle. The vehicle is an electric vehicle having the rotary electric machine 40 as a power source. The power transmission device 100 transmits the power from the rotary electric machine 40 to the drive wheels. The power transmission device 100 can also transmit the power from the drive wheels to the rotary electric machine 40.

[0012] The case 10 has a case body 11 and a cover 12. The case body 11 is provided on one side in the axial direction (the right side in the figure), and the cover 12 is provided on the other side in the axial direction (the left side in the figure). The axial direction is the extending direction of the axis (power transmission axis) of the power transmission device 100, and the extending directions of the first shaft 21, the second shaft 22, and the third shaft 33 described later respectively correspond to the axial direction.

[0013] The case body 11 has a housing portion 11a, and the cover 12 has a housing portion 12a. The housing portion 11a opens toward the left side in the figure, and the housing portion 12a opens toward the right side in the figure. The cover 12 is provided on the case body 11 and closes the opening of the housing portion 11a with the opening of the housing portion 12a. The space formed by the housing portion 11a and the housing portion 12a constitutes the housing chamber S of the case 10. The housing chamber S is formed by the case body 11 and the cover 12 being joined together.

[0014] The case body 11 further has a cylindrical portion 11b. The cylindrical portion 11b is provided on the right side in the figure rather than the housing portion 11a. The rotary electric machine 40 is disposed in the cylindrical portion 11b. Therefore, the power transmission device 100 can also be grasped as having a configuration further including the rotary electric machine 40. The rotary electric machine 40 is fixed to the inner circumference of the cylindrical portion 11b.

[0015] The rotating electrical machine 40 has a rotor 41, a stator 42, a rotating shaft 43, and a motor case 44. The rotor 41 is accommodated in the stator 42, and the stator 42 is fixed to the inner circumference of the cylindrical portion 11b via the motor case 44. The rotating shaft 43 protrudes into the accommodating portion 11a through a through-hole penetrating the partition wall between the accommodating portion 11a and the cylindrical portion 11b, and a seal member is provided between the through-hole and the rotating shaft 43. For this reason, the inside of the cylindrical portion 11b, which is the space where the rotating electrical machine 40 is disposed, is separated from the accommodating chamber S, which is the space where the speed reduction mechanism 20 and the differential gear 30 are disposed, and does not constitute the accommodating chamber S.

[0016] The speed reduction mechanism 20 is a gear mechanism and has a first shaft 21 and a second shaft 22. The first shaft 21 is connected to the rotating electrical machine 40. The first shaft 21 is connected to the rotating electrical machine 40 so as to be capable of power transmission. The connection may be a connection via other components (for example, a clutch or other gear mechanisms). In the present embodiment, the first shaft 21 is directly connected to the rotating shaft 43, and thus is directly connected to the rotating electrical machine 40. That the first shaft 21 is directly connected to the rotating electrical machine 40 means that the first shaft 21 is disposed on the axis of the rotating electrical machine 40 and is directly connected to the rotating electrical machine 40 without passing through a clutch or other gear mechanisms.

[0017] The first shaft 21 has a first gear portion 211. The first gear portion 211 is constituted by a first gear G1. The first gear portion 211 is integrally formed with the first shaft 21 and outputs the power from the rotating electrical machine 40. The first shaft 21 is supported by the case main body 11 by a bearing 51 on one side in the axial direction and is supported by the cover 12 by a bearing 52 on the other side in the axial direction, and thus is axially supported by the case 10. A park gear 212 is also provided on the first shaft 21 in the portion between the first gear portion 211 and the bearing 51. The first shaft 21 constitutes the first shaft of the power transmission device 100.

[0018] The second shaft 22 has a second gear portion 221. The second gear portion 221 is composed of a second gear G2 and a third gear G3. The second gear G2 is integrated with the second shaft 22 by press-fitting, and the third gear G3 is integrally formed on the second shaft 22. The third gear G3 is arranged on the right side of the second gear G2 in the figure, that is, on the side closer to the rotary electric machine 40. The second gear G2 meshes with the first gear G1, and power is input to the second gear G2 from the first gear G1.

[0019] The power input to the second gear G2 is output from the third gear G3. Therefore, the second gear portion 221 receives power input from the first gear G1 and outputs the input power. The second gear G2 is set to have more teeth than the first gear G1, and together with the first gear G1, they constitute a first reduction gear stage. The second shaft 22 is supported by the case body 11 by a bearing 53 on one side in the axial direction, and supported by the cover 12 by a bearing 54 on the other end side in the axial direction, so as to be axially supported by the case 10. The second shaft 22 constitutes the second shaft of the power transmission device 100.

[0020] The differential gear 30 is a differential gear mechanism, and has a differential case 31, a fourth gear G4 which is a final gear, and a differential portion 32. The differential case 31 is supported by a bearing 55 provided on the case body 11 and a bearing 56 provided on the cover 12, so as to be axially supported by the case 10. The fourth gear G4 is coaxially fixed to the outer wall portion of the differential case 31. The fourth gear G4 meshes with the third gear G3, and power is input to the fourth gear G4 from the third gear G3. The differential case 31, together with the fourth gear G4, constitutes the third shaft 33 of the power transmission device 100. The fourth gear G4 constitutes the third gear portion 331 of the third shaft 33.

[0021] The differential case 31 houses the differential portion 32, and the differential portion 32 distributes and outputs the power input to the differential case 31 via the fourth gear G4 to each of the drive wheels in the vehicle left-right direction. Therefore, the fourth gear G4 which is the third gear portion 331 is connected to the drive wheels via the differential case 31 and the differential portion 32, and transmits the input power to the drive wheels.

[0022] The fourth gear G4 is set to have more teeth than the third gear G3, and together with the third gear G3, constitutes the second reduction gear stage. Therefore, in the power transmission device 100, two-stage reduction is performed by the first gear G1 and the second gear G2, and the third gear G3 and the fourth gear G4.

[0023] The power transmission device 100 is a three-shaft configuration power transmission device in which a total of three shafts, namely the first shaft 21, the second shaft 22, and the third shaft 33, are arranged in the housing chamber S as power transmission shafts. The shafts of the power transmission device 100 are composed of a plurality of shafts that are sequentially connected from the radial direction by the meshing of gear portions.

[0024] FIG. 2 is a view of the housing chamber S seen from the cover 12 side in the axial direction. In FIG. 2, the housing chamber S is shown in a cross section at the mating surface position of the case body 11 and the cover 12. Therefore, FIG. 2 shows the inside of the housing portion 11a of the case body 11 as the housing chamber S. In FIG. 2, the vertical direction of the figure corresponds to the gravitational direction, and the horizontal direction of the figure corresponds to the vehicle longitudinal direction.

[0025] As shown in FIG. 2, the case 10 has an oil sump 10a, an air breather chamber 10b, an oil catch tank 10c, and an oil guide 10d. The wall portions forming these components 10a to 10d are also formed on the cover 12 side, and these components 10a to 10d are formed in the case 10 in a state where the case body 11 and the cover 12 are mated.

[0026] The oil sump 10a is provided at the lower part of the case 10. The oil in the oil sump 10a is used for scraping up and circulating, and the scraped-up oil is, for example, used for lubrication and then falls by the action of gravity and is stored again in the oil sump 10a. The fourth gear G4 is immersed in the oil sump 10a and scrapes up the oil in the oil sump 10a. In FIG. 2, the oil level height of the oil sump 10a shows the oil level height during device driving. The fourth gear G4 is provided at a height such that most of the lower half is immersed in the oil sump 10a during device driving. The fourth gear G4 is provided at a height such that at least a part of it is immersed in the oil sump 10a regardless of whether the device is driving or stopped.

[0027] The air breather chamber 10b is provided in the case 10 and separates the air and oil in the accommodation chamber S and communicates with the atmosphere. The inside of the case 10 is formed as a space surrounded by the outer wall portion of the case 10 (the wall portion constituting the outer wall of the case 10), and the accommodation chamber S is partitioned as a space in the case 10 where the speed reduction mechanism 20 and the differential gear 30 are arranged.

[0028] The air breather chamber 10b is provided above and in the vicinity of the third shaft 33. Above and below mean an arrangement that appears to overlap in the gravitational direction in a predetermined direction view including an axial view and a radial view. For example, when the first element overlaps the second element in the gravitational direction in the axial view, if the first element is located higher than the second element, the first element is above the second element. In this case, in the radial view, the first element and the second element may overlap or may be offset.

[0029] The air breather chamber 10b is provided above the third shaft 33 by having a portion that overlaps the third shaft 33 in the gravitational direction, that is, overlaps in the gravitational direction, at a position higher than the third shaft 33. The air breather chamber 10b is provided within a range that does not protrude beyond the fourth gear G4 in the left - right direction of the figure. The air breather chamber 10b is provided at a position higher than the fourth gear G4 at each position in the left - right direction of the figure, and thus is provided at a position higher than the fourth gear G4 as a whole.

[0030] The air breather chamber 10b has a wall portion 10ba having a shape curved along the third shaft 33. The air breather chamber 10b is provided with such a curved shape with respect to the third shaft 33, and thus is provided in the vicinity of the third shaft 33 by being provided as close as possible to the third shaft 33. The wall portion 10ba constitutes the lower wall portion of the air breather chamber 10b, and the curved shape of the wall portion 10ba is a shape along the fourth gear G4, which is the maximum outer diameter portion of the third shaft 33.

[0031] The air breather chamber 10b has a front chamber R1 and a labyrinth chamber R2. In the air breather chamber 10b, the front chamber R1 is partitioned on the lower side in the gravity direction, and the labyrinth chamber R2 is partitioned on the upper side in the gravity direction. In the labyrinth chamber R2, a plurality of walls are alternately provided on the case body 11 side and the cover 12 side in the vehicle front-rear direction, that is, the left-right direction in the figure, and a labyrinth passage is formed by the plurality of walls. The arrow shown by the broken line indicates the air flow path passing through the air breather chamber 10b, and the air in the accommodation chamber S passes through the air breather chamber 10b as follows.

[0032] That is, the front chamber R1 communicates with the accommodation chamber S on the cover 12 side, and air first flows into the front chamber R1 and then flows into the labyrinth chamber R2 through the front chamber R1. The front chamber R1 suppresses the inflow of oil into the labyrinth chamber R2 by circulating air before flowing into the labyrinth chamber R2. Oil can be discharged from the front chamber R1 to the accommodation chamber S through the discharge hole. In the labyrinth chamber R2, air is separated from oil by flowing through the labyrinth passage. The labyrinth chamber R2 communicates with the atmosphere on the cover 12 side, and air is discharged to the atmosphere after flowing through the labyrinth chamber R2.

[0033] The oil catch tank 10c is provided above and in the vicinity of the first shaft 21 in the case 10. The oil catch tank 10c is provided above the first shaft 21 by having a portion that overlaps the first shaft 21 in the gravity direction. The oil catch tank 10c protrudes from the first shaft 21 to the side away from the third shaft 33 in the left-right direction in the figure, that is, the left side in the figure. Therefore, in the oil catch tank 10c, a portion that does not protrude from the first shaft 21 in the left-right direction in the figure is provided above the first shaft 21. The portion of the oil catch tank 10c that protrudes from the first shaft 21 in the left-right direction in the figure, that is, the portion of the oil catch tank 10c that does not overlap the first shaft 21 in the gravity direction, is provided at a position higher than the axis A1 of the first shaft 21.

[0034] The oil catch tank 10c has a wall portion 10ca that is curved along the first axis 21. The oil catch tank 10c is provided in the vicinity of the first axis 21, for example, such that the wall portion 10ca is provided close enough to have a curved shape along the first axis 21. The curved shape of the wall portion 10ca is shaped along the park gear 212 which is the maximum outer diameter portion of the first axis 21.

[0035] The wall portion 10ca extends downward while curving toward the left side of the figure and connects to the wall portion 10cb. The wall portion 10cb extends obliquely upward from the connection portion with the wall portion 10ca toward the left side of the figure and connects to the outer wall portion that constitutes the accommodation portion 11a. The wall together with the wall portion 10ca and the wall portion 10cb constitutes the oil catch tank 10c. The wall portion 10cb constitutes the bottom of the oil catch tank 10c together with the wall portion 10ca.

[0036] The wall portion 10ca has a top at a position corresponding to the axis A1 of the first axis 21 in the left - right direction of the figure, and extends downward while curving even on the side closer to the third axis 33 than the top, that is, on the right side of the figure. The wall portion 10ca connects to the oil guide 10d on the right side of the figure from the top.

[0037] In the upper region of the accommodation chamber S between the first axis 21 and the third axis 33, as described above, by providing the air breather chamber 10b above and in the vicinity of the third axis 33 and providing the oil catch tank 10c above and in the vicinity of the first axis 21, a space is created. For this reason, the second axis 22 is arranged in this space, whereby the second axis 22 is arranged outside the oil sump 10a, that is, in the air, in the accommodation chamber S. As a result, the stirring resistance of the shaft is suppressed compared to the case where the second axis 22 is immersed in the oil sump 10a. The second axis 22 is arranged outside the oil sump 10a regardless of whether the device is driving or stopped. The second axis 22 may be provided at a height where it is arranged outside the oil sump 10a at least during device driving among device driving and device stop.

[0038] The axis A2 of the second shaft 22 arranged as described above is set at a position higher than the axis A1 of the first shaft 21 and the axis A3 of the third shaft 33. The first shaft 21 and the third shaft 33 are arranged side by side in the left - right direction of the figure. The first shaft 21 is preferably provided at a height where it does not dip into the oil sump 10a during device drive. For this reason, the axis A1 of the first shaft 21 is set at a position slightly higher than the axis A3 of the third shaft 33.

[0039] The oil catch tank 10c stores the oil scraped up by the fourth gear G4 and is provided above and in the vicinity of the first shaft 21. That is, the oil catch tank 10c is provided at a position away from the fourth gear G4.

[0040] For this reason, an oil guide 10d is provided above the second shaft 22. The oil guide 10d introduces the oil scraped up by the fourth gear G4 into the oil catch tank 10c. Thereby, even if the oil catch tank 10c is provided above and in the vicinity of the first shaft 21, the oil scraped up by the fourth gear G4 can be captured by the oil catch tank 10c.

[0041] The oil guide 10d has a plate - like shape and is provided in the accommodation chamber S. The oil guide 10d is provided above the second shaft 22 by having a portion that overlaps the second shaft 22 in the gravitational direction at a position higher than the second shaft 22. The oil guide 10d is provided in the vicinity of the second shaft 22 and has a shape curved along the second shaft 22. The shape curves along the second gear G2 which is the maximum outer diameter portion of the second shaft 22. The oil guide 10d curves downward while extending toward the left side of the figure and connects to the wall portion 10ca. The oil guide 10d has a top at a position corresponding to the axis A2 of the second shaft 22 in the left - right direction of the figure, and extends downward while curving within a range where it does not interfere with the fourth gear G4 from the top toward the right side of the figure.

[0042] A part of the oil guide 10d may also serve as a wall portion of the oil catch tank 10c. That is, a part of the oil guide 10d may function as a wall portion of the oil catch tank 10c. As a result, the oil catch tank 10c is further constituted by a part of the oil guide 10d. Consequently, the oil catch tank 10c is provided above the first shaft 21 in such a manner that it has a portion overlapping the axis A1 of the first shaft 21 in the direction of gravity at a position higher than the first shaft 21.

[0043] An oil passage 10e is formed in the case 10. The oil passage 10e opens into the bottom of the oil catch tank 10c and introduces the oil stored in the oil catch tank 10c to a bearing 51 that supports the first shaft 21. The oil passage 10e is formed in the case body 11. A similar oil passage may be provided in, for example, the cover 12. In this case, oil can be introduced from the oil catch tank 10c to the bearing 52.

[0044] Next, the main operational effects of this embodiment will be described.

[0045] FIG. 3 is a diagram showing a comparative example. In FIG. 3, a case 10X is shown as a comparative example. The case 10X has a case body 11X provided with an air breather chamber 10bX and an oil catch tank 10cX that are different in arrangement and the like from this embodiment. In FIG. 3, the first shaft 21, the second shaft 22, and the third shaft 33 are schematically shown by arrows indicating the rotational direction.

[0046] In this example, the air breather chamber 10bX and the oil catch tank 10cX are provided in the upper region inside the case 10 between the first shaft 21 and the third shaft 33. The oil catch tank 10cX opens toward the oil scattered from the rotating third shaft 33. For this reason, in this example, a part of the oil scraped up by the third shaft 33 can be directly captured by the oil catch tank 10cX. Also, the oil stored in the oil catch tank 10cX can be used for lubricating the bearing 51 that supports the first shaft 21.

[0047] However, in this example, there is no space to arrange the second shaft 22 in the upper region within the case 10 between the first shaft 21 and the third shaft 33, and the second shaft 22 has to be immersed in the oil sump 10a. As a result, when the device is driven, stirring resistance acts not only on the third shaft 33 but also on the second shaft 22, and the power transmission efficiency deteriorates accordingly. In contrast, the power transmission device 100 according to the present embodiment is configured as follows.

[0048] (1) The power transmission device 100 includes a case 10 having an oil sump 10a at the bottom, and a first shaft 21, a second shaft 22, and a third shaft 33 that are shaft-supported by the case 10. The first shaft 21 is connected to a rotary electric machine 40. The first shaft 21 has a first gear portion 211 that outputs power from the rotary electric machine 40. The second shaft 22 has a second gear portion 221 to which power is input from the first gear portion 211 and that outputs the input power. The third shaft 33 has a third gear portion 331 to which power is input from the second gear portion 221 and at least a part of which is immersed in the oil sump 10a. The case 10 has an air breather chamber 10b that separates the air and oil in the accommodation chamber S within the case 10 and communicates with the atmosphere, an oil catch tank 10c that stores the oil scooped up by the third gear portion 331, and an oil guide 10d that guides the oil scooped up by the third gear portion 331 to the oil catch tank 10c. The air breather chamber 10b is provided above and in the vicinity of the third shaft 33. The oil catch tank 10c is provided above and in the vicinity of the first shaft 21. The oil guide 10d is provided above the second shaft 22. The second shaft 22 is arranged outside the oil sump 10a within the case 10.

[0049] According to such a configuration, when power is transmitted from the first shaft 21 to the third shaft 33 via the second shaft 22, the air breather chamber 10b is provided above and in the vicinity of the third shaft 33, and the oil catch tank 10c is provided above and in the vicinity of the first shaft 21. Then, the oil scraped up by the third gear portion 331 is introduced into the oil catch tank 10c by an oil guide 10d provided above the second shaft 22. As a result, it becomes possible to provide the second shaft 22 in the upper region inside the case 10 between the first shaft 21 and the third shaft 33, and the second shaft 22 is disposed outside the oil sump 10a. Consequently, the stirring resistance of the shaft can be reduced as compared with the case where the second shaft 22 is disposed so as to be immersed in the oil sump 10a, and the stirring resistance of the shaft in the oil sump 10a can be improved.

[0050] (2) In the present embodiment, a total of three shafts, i.e., the first shaft 21, the second shaft 22, and the third shaft 33, are arranged as power transmission shafts inside the case 10. In the case of such a configuration of the power transmission device 100, the technical significance is great in that the stirring resistance that may occur in the oil sump 10a due to the arrangement of the second shaft 22 can be improved.

[0051] (3) The case 10 further has an oil passage 10e for introducing the oil stored in the oil catch tank 10c to a bearing 51 that supports the first shaft 21. Thereby, not only the oil is stored in the oil catch tank 10c to lower the oil level of the oil sump 10a during device driving, but also the stored oil can be discharged from the oil catch tank 10c while being effectively utilized for lubrication. Therefore, even when the oil catch tank 10c is provided above and in the vicinity of the first shaft 21, the oil catch tank 10c can be used for lowering the oil level of the oil sump 10a and lubrication during device driving.

[0052] As described above, the embodiments of the present invention have been described. However, the above embodiments merely show a part of the application examples of the present invention, and are not intended to limit the technical scope of the present invention to the specific configurations of the above embodiments.

Explanation of Reference Numerals

[0053] 10 Case 10a Oil sump 10b Air breather chamber 10c Oil catch tank 10d Oil guide 10e Oil passage 21 First shaft 211 First gear portion 22 Second shaft 221 Second gear portion 33 Third shaft 331 Third gear portion 40 Rotating electric machine (power source) 51 Bearing 100 Power transmission device S Accommodation chamber

Claims

1. It has a case with an oil reservoir at the lower part, and a first shaft, a second shaft, and a third shaft that are shaft-supported by the case. The first shaft is connected to a power source and has a first gear portion that outputs power from the power source. The second shaft has a second gear portion to which power is input from the first gear portion and that outputs the input power. The third shaft has a third gear portion to which power is input from the second gear portion and at least a part of which is immersed in the oil reservoir. It is a power transmission device, wherein the case has an air breather chamber that separates air and oil in the case and communicates with the atmosphere, an oil catch tank that stores the oil scraped up by the third gear portion, and an oil guide that introduces the oil scraped up by the third gear portion into the oil catch tank. It has, wherein the air breather chamber is provided above and in the vicinity of the third shaft, the oil catch tank is provided above and in the vicinity of the first shaft, the oil guide is provided above the second shaft, the second shaft is set at a position higher than the axis of the first shaft and the axis of the third shaft and is arranged outside the oil reservoir in the case. Power transmission device.

2. The power transmission device according to Claim 1, wherein a total of three shafts, namely the first shaft, the second shaft, and the third shaft, are arranged as power transmission shafts in the case. Power transmission device.

3. The power transmission device according to Claim 1 or 2, wherein the case further has an oil passage that introduces the oil stored in the oil catch tank into a bearing that supports the first shaft. Power transmission device.

Images