Power transmission device

Abstract

The present invention improves the stirring resistance of a shaft in an oil reservoir. A power transmission device includes a case having an oil reservoir in a lower portion thereof, and a first shaft, a second shaft, and a third shaft pivotally supported by the case. The first shaft is connected to a power source, and has a first gear part 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 which outputs the input power. The third shaft has a third gear part to which power is input from the second gear part, and at least a part of which is immersed in the oil reservoir. The box body is provided with a ventilation chamber which separates air and oil in the box body and communicates with the atmosphere; an oil collecting tank for storing the oil stirred up by the third gear part; and an oil guide which guides the oil stirred up by the third gear part into the oil collection tank. The ventilation chamber is provided above and near the third shaft. The oil collecting tank is arranged above and near the first shaft. The oil guide is disposed above the second shaft. The second shaft is disposed outside the oil reservoir inside the housing.

Description

Technical Field

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

[0002] Patent Document 1 discloses a cooling structure for an electric motor in which an intermediate shaft is disposed in an oil reservoir.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: (Japanese) Unexamined Patent Publication No. 2004-180477 (see, for example, FIG. 4 ) Summary of the invention

[0006] Problems to be solved by the invention

[0007] In addition to the oil reservoir at the bottom of the housing, the power transmission device sometimes has a ventilation chamber or an oil collecting tank in the housing. The ventilation chamber separates the air and oil in the housing and communicates with the atmosphere. The oil collecting tank stores the oil stirred up by the gear portion of the shaft immersed in the oil reservoir. The oil collecting tank is used, for example, to lower the oil level in the oil reservoir when the device is driven by storing oil. If the oil level is lowered, the stirring resistance of the shaft immersed in the oil reservoir is reduced, and therefore, the power transmission efficiency of the device is improved.

[0008] However, the breather chamber or the oil collecting tank may restrict the arrangement of the shaft of the power transmission device. Therefore, depending on the arrangement of the breather chamber or the oil collecting tank, the shaft that does not necessarily need to be immersed in the oil reservoir must be immersed in the oil reservoir, resulting in a possible increase in stirring resistance.

[0009] The present invention has been made in view of such a problem, and an object of the present invention is to improve the stirring resistance of the shaft in the oil reservoir.

[0010] Technical solutions to solve problems

[0011] A power transmission device according to one aspect of the present invention comprises a housing having an oil reservoir at the bottom, and a first shaft, a second shaft, and a third shaft axially supported by the housing. 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 that receives power from the first gear portion and outputs the input power. The third shaft has a third gear portion that receives power from the second gear portion and at least partially immerses in the oil reservoir. The housing comprises: a ventilation chamber that separates air and oil in the housing and communicates with the atmosphere; an oil collecting tank that stores oil stirred up by the third gear portion; and an oil guide that guides the oil stirred up by the third gear portion into the oil collecting tank. The ventilation chamber is disposed above and near the third shaft. The oil collecting tank is disposed above and near the first shaft. The oil guide is disposed above the second shaft. The second shaft is disposed outside the oil reservoir in the housing.

[0012] Effects of the Invention

[0013] According to this form, when power is transmitted from the first shaft to the third shaft via the second shaft, the ventilation chamber is arranged above and near the third shaft, and the oil collecting tank is arranged above and near the first shaft. Moreover, the oil stirred up by the third gear part is introduced into the oil collecting tank by the oil guide member arranged above the second shaft. Thus, the second shaft can be arranged in the upper space of the box body between the first shaft and the third shaft, and the second shaft is arranged outside the oil storage part. As a result, compared with the configuration in which the second shaft is immersed in the oil storage part, the stirring resistance of the shaft can be reduced, and the stirring resistance of the shaft in the oil storage part can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic structural diagram of a power transmission device according to an embodiment.

[0015] Figure 2 This is a diagram showing the inside of the case from the shell side when viewed from the axial direction.

[0016] Figure 3 It is a figure which shows a comparative example. DETAILED DESCRIPTION

[0017] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0018] Figure 1 is a schematic diagram of the structure of the power transmission device 100 according to the present embodiment. Figure 1 In FIG. 4 , the rotating electric machine 40 is indicated by a double-dashed line. Figure 1As shown, the power transmission device 100 includes a housing 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 using a rotary motor 40 as a power source. The power transmission device 100 transmits power from the rotary motor 40 to the drive wheels. The power transmission device 100 can also transmit power from the drive wheels to the rotary motor 40.

[0019] The housing 10 includes a housing body 11 and a housing 12. The housing body 11 is disposed on one axial side (the right side of the figure), and the housing 12 is disposed on the other axial side (the left side of the figure). The axial direction is the extension direction of the shaft (power transmission shaft) of the power transmission device 100, and the extension directions of the first shaft 21, the second shaft 22, and the third shaft 33 described later correspond to the axial direction, respectively.

[0020] The box body 11 has a storage portion 11a, and the shell 12 has a storage portion 12a. The storage portion 11a opens toward the left side of the figure, and the storage portion 12a opens toward the right side of the figure. The shell 12 is provided on the box body 11, and the opening of the storage portion 11a is blocked by the opening of the storage portion 12a. The space formed by the storage portion 11a and the storage portion 12a constitutes the storage chamber S of the box body 10. The storage chamber S is formed by the box body 11 and the shell 12 being combined with each other.

[0021] The housing body 11 further includes a cylindrical portion 11b. The cylindrical portion 11b is provided on the right side of the housing portion 11a in the figure. A rotary motor 40 is arranged in the cylindrical portion 11b. Therefore, the power transmission device 100 can also be understood as having a structure further including the rotary motor 40. The rotary motor 40 is fixed to the inner periphery of the cylindrical portion 11b.

[0022] The rotary electric machine 40 includes a rotor 41, a stator 42, a rotary 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 periphery of the cylindrical portion 11b via the motor case 44. The rotary shaft 43 protrudes into the accommodating portion 11a via a through hole that penetrates the partition wall in the accommodating portion 11a and the cylindrical portion 11b, and a sealing member is provided between the through hole and the rotary shaft 43. Therefore, the space in which the rotary electric machine 40 is arranged, that is, the inside of the cylindrical portion 11b, is distinguished from the space in which the speed reduction mechanism 20 and the differential gear 30 are arranged, that is, the accommodating chamber S, and does not constitute the accommodating chamber S.

[0023] The speed reduction mechanism 20 is a gear mechanism, having a first shaft 21 and a second shaft 22. The first shaft 21 is connected to the rotating motor 40. The first shaft 21 is connected to the rotating motor 40 so as to transmit power. The connection may also be a connection via other structures (e.g., a clutch or other gear mechanisms). In the present embodiment, the first shaft 21 is directly connected to the rotating motor 40 by being directly connected to the rotating shaft 43. The direct connection between the first shaft 21 and the rotating motor 40 means that the first shaft 21 is arranged on the axis of the rotating motor 40 and is directly connected to the rotating motor 40 without passing through a clutch or other gear mechanisms.

[0024] The first shaft 21 has a first gear portion 211. The first gear portion 211 is composed of a first gear G1. The first gear portion 211 is formed integrally with the first shaft 21, and outputs power from the rotating motor 40. The first shaft 21 is supported by a bearing 51 on one side of the axial direction to the housing body 11, and is supported by a bearing 52 on the other side of the axial direction to the housing 12, thereby being axially supported by the housing 10. A parking gear 212 is also provided on the first shaft 21 between the first gear portion 211 and the bearing 51. The first shaft 21 constitutes the first shaft of the power transmission device 100.

[0025] 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 pressed into the second shaft 22 to form an integral body, and the third gear G3 is formed integrally with the second shaft 22. The third gear G3 is arranged on the right side of the figure than the second gear G2, and is therefore arranged on the side close to the rotating motor 40. The second gear G2 meshes with the first gear G1, and power is input from the first gear G1 to the second gear G2.

[0026] The power input to the second gear G2 is output from the third gear G3. Therefore, the second gear portion 221 receives power 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, it constitutes a first reduction gear stage. The second shaft 22 is supported by a bearing 53 on one axial side of the housing body 11, and is supported by a bearing 54 on the other axial end side of the housing 12, thereby being axially supported by the housing 10. The second shaft 22 constitutes the second shaft of the power transmission device 100.

[0027] The differential gear 30 is a differential gear mechanism, and includes a differential case 31, a fourth gear G4 as a final gear, and a differential portion 32. The differential case 31 is axially supported on the case 10 by a bearing 55 provided on the case body 11 and a bearing 56 provided on the housing 12. The fourth gear G4 is coaxially fixed to the outer wall of the differential case 31. The fourth gear G4 meshes with the third gear G3, and power is input from the third gear G3 to the fourth gear G4. The differential case 31 and the fourth gear G4 together constitute 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.

[0028] The differential case 31 accommodates the differential unit 32, and the differential unit 32 distributes and outputs the power input to the differential case 31 via the fourth gear G4 to the driving wheels in the left and right directions of the vehicle. Therefore, the fourth gear G4 as the third gear unit 331 is connected to the driving wheels via the differential case 31 and the differential unit 32, and transmits the input power to the driving wheels.

[0029] The fourth gear G4 has a larger number of teeth than the third gear G3 and forms a second reduction gear stage together with the third gear G3. 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.

[0030] The power transmission device 100 is a three-shaft 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 as power transmission shafts in the storage chamber S. The shafts of the power transmission device 100 are composed of a plurality of shafts sequentially connected in radial direction by meshing of gear parts.

[0031] Figure 2 This is a diagram showing the storage chamber S from the housing 12 side when viewed from the axial direction. Figure 2 In FIG. 1 , the storage chamber S is represented by a cross section at the joint surface of the box body 11 and the shell 12. Therefore, Figure 2 The interior of the storage portion 11a of the box body 11 is shown as a storage chamber S. Figure 2 In the figure, the up-down direction corresponds to the direction of gravity, and the left-right direction corresponds to the front-rear direction of the vehicle.

[0032] like Figure 2 As shown, the housing 10 has an oil reservoir 10a, a vent chamber 10b, an oil collecting tank 10c, and an oil guide 10d. The wall portions forming these structures 10a to 10d are also formed on the shell 12 side, and these structures 10a to 10d are formed in the housing 10 in a state where the housing body 11 and the shell 12 are combined.

[0033] The oil reservoir 10a is provided at the lower part of the housing 10. The oil in the oil reservoir 10a is used for stirring and circulation, and the stirred oil falls due to gravity after being used for lubrication and is stored again in the oil reservoir 10a. The fourth gear G4 is immersed in the oil reservoir 10a, and the oil in the oil reservoir 10a is stirred. Figure 2 The oil level when the device is driven is shown as the oil level of the oil reservoir 10a. The fourth gear G4 is set at a height where most of its lower half is immersed in the oil reservoir 10a when the device is driven. The fourth gear G4 is set at a height where at least a part of it is immersed in the oil reservoir 10a regardless of whether the device is driven or stopped.

[0034] The ventilation chamber 10b is provided in the housing 10, and separates the air and oil in the storage chamber S and communicates with the atmosphere. The housing 10 is formed as a space surrounded by the outer wall portion of the housing 10 (the wall portion constituting the outer wall of the housing 10), and the storage chamber S is divided in the housing 10 as a space in which the speed reduction mechanism 20 and the differential gear 30 are arranged.

[0035] The ventilation chamber 10b is provided above and near the third axis 33. Above and below refer to a configuration that appears to overlap in the direction of gravity when viewed from a specified direction including axial observation or radial observation. For example, when the first element and the second element overlap in the direction of gravity when viewed from the axial direction, if the position of the first element is higher than the second element, the first element is located above the second element. In this case, when viewed from the radial direction, the first element and the second element may overlap or may be offset.

[0036] The ventilation chamber 10b is provided above the third shaft 33 because it has a portion that overlaps with the third shaft 33 in the gravity direction at a position higher than the third shaft 33, that is, is stacked in the gravity direction. The ventilation chamber 10b is provided in a range that does not protrude from the fourth gear G4 in the left-right direction of the figure. The ventilation chamber 10b is provided at a position higher than the fourth gear G4 as a whole because the positions in the left-right direction of the figure are respectively provided at a position higher than the fourth gear G4.

[0037] The ventilation chamber 10b has a wall portion 10ba that is curved along the third shaft 33. The ventilation chamber 10b is provided with such a curved shape relative to the third shaft 33, and thus, is provided near the third shaft 33 by being provided as close to the third shaft 33 as possible. The wall portion 10ba constitutes the lower wall portion of the ventilation chamber 10b, and the curved shape of the wall portion 10ba is along the shape of the fourth gear G4, which is the largest outer diameter portion of the third shaft 33.

[0038] The ventilation chamber 10b has a front chamber R1 and a labyrinth chamber R2. In the ventilation chamber 10b, the front chamber R1 is divided into a lower side in the direction of gravity, and the labyrinth chamber R2 is divided into an upper side in the direction of gravity. In the labyrinth chamber R2, a plurality of walls are alternately provided on the side of the box body 11 and the side of the shell 12 along the front-rear direction of the vehicle, that is, the left-right direction of the figure, and a labyrinth passage is formed by the plurality of walls. The arrows indicated by the dotted lines indicate the flow path of the air passing through the ventilation chamber 10b, and the air of the storage chamber S passes through the ventilation chamber 10b as described below.

[0039] That is, the front chamber R1 is connected to the storage chamber S on the housing 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 allowing air to flow before flowing into the labyrinth chamber R2. The oil can be discharged from the front chamber R1 to the storage chamber S through the discharge hole. In the labyrinth chamber R2, the air is separated from the oil by flowing in the labyrinth passage. The labyrinth chamber R2 is connected to the atmosphere on the housing 12 side, and the air is released to the atmosphere after flowing in the labyrinth chamber R2.

[0040] The oil collecting tank 10c is disposed above and near the first axis 21 in the housing 10. The oil collecting tank 10c is disposed above the first axis 21 because it has a portion overlapping with the first axis 21 in the direction of gravity. The oil collecting tank 10c is disposed so as to protrude further away from the third axis 33 than the first axis 21 in the left-right direction of the figure, that is, to the left side of the figure. Therefore, the portion of the oil collecting tank 10c that does not protrude more than the first axis 21 in the left-right direction of the figure is disposed above the first axis 21. The portion of the oil collecting tank 10c that protrudes more than the first axis 21 in the left-right direction of the figure, that is, the portion of the oil collecting tank 10c that does not overlap with the first axis 21 in the direction of gravity, is disposed at a position higher than the axis A1 of the first axis 21.

[0041] The oil collecting tank 10c has a wall portion 10ca having a curved shape along the first shaft 21. The oil collecting tank 10c is provided near the first shaft 21, for example, by being provided close to the wall portion 10ca having a curved shape along the first shaft 21. The curved shape of the wall portion 10ca is a shape along the maximum outer diameter portion of the first shaft 21, that is, the parking gear 212.

[0042] The wall portion 10ca is bent toward the left side of the figure and extends downward and is connected 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 is connected to the outer wall portion constituting the accommodating portion 11a. This wall portion, the wall portion 10ca, and the wall portion 10cb together constitute the oil collecting tank 10c. The wall portion 10cb and the wall portion 10ca together constitute the bottom of the oil collecting tank 10c.

[0043] The wall portion 10ca has a top at a position corresponding to the axis A1 of the first shaft 21 in the left-right direction of the figure, and extends downward while bending on the right side of the figure closer to the third shaft 33 than the top. The wall portion 10ca is connected to the oil guide 10d on the right side of the figure than the top.

[0044] In the area above the storage chamber S between the first shaft 21 and the third shaft 33, a space can be formed by arranging the ventilation chamber 10b above and near the third shaft 33 and arranging the oil collecting tank 10c above and near the first shaft 21 as described above. Therefore, the second shaft 22 is arranged in the space, and thus, the second shaft 22 is arranged outside the oil reservoir 10a, that is, in the atmosphere, in the storage chamber S. As a result, the stirring resistance of the shaft is suppressed compared to the case where the second shaft 22 is immersed in the oil reservoir 10a. Regardless of whether the device is driven or stopped, the second shaft 22 is arranged outside the oil reservoir 10a. The second shaft 22 may also be arranged at a height outside the oil reservoir 10a when the device is driven and when the device is stopped.

[0045] The axis A2 of the second shaft 22 configured 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 in the left-right direction of the figure. The first shaft 21 is preferably set at a height that is not immersed in the oil reservoir 10a when the device is driven. Therefore, the axis A1 of the first shaft 21 is set at a position slightly higher than the axis A3 of the third shaft 33.

[0046] The oil collecting tank 10c stores the oil stirred up by the fourth gear G4, and is provided above and near the first shaft 21. That is, the oil collecting tank 10c is provided at a position away from the fourth gear G4.

[0047] Therefore, an oil guide 10d is provided above the second shaft 22. The oil guide 10d guides the oil stirred up by the fourth gear G4 into the oil collecting tank 10c. Thus, even if the oil collecting tank 10c is provided above and near the first shaft 21, the oil stirred up by the fourth gear G4 can be captured by the oil collecting tank 10c.

[0048] The oil guide 10d has a plate-like shape and is provided in the storage chamber S. The oil guide 10d is provided above the second shaft 22 because it has a portion that overlaps with the second shaft 22 in the direction of gravity at a position higher than the second shaft 22. The oil guide 10d is provided near the second shaft 22 and has a shape that is bent along the second shaft 22. This shape is bent along the second gear G2, which is the largest outer diameter portion of the second shaft 22. The oil guide 10d extends downward while bending toward the left side of the figure and is connected 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 from the top to the right side of the figure while bending within a range that does not interfere with the fourth gear G4.

[0049] A part of the oil guide 10d may also serve as the wall of the oil collecting tank 10c. That is, a part of the oil guide 10d may also function as the wall of the oil collecting tank 10c. Thus, the oil collecting tank 10c is also constituted by a part of the oil guide 10d. As a result, the oil collecting tank 10c is provided above the first shaft 21 in a form having a part that overlaps with the axis A1 of the first shaft 21 in the gravity direction at a position higher than the first shaft 21.

[0050] An oil passage 10e is formed in the housing 10. The oil passage 10e opens in the bottom of the oil collecting tank 10c, and introduces the oil stored in the oil collecting tank 10c into the bearing 51 that supports the first shaft 21. The oil passage 10e is formed in the housing body 11. The same oil passage may be provided in the housing 12, for example. In this case, oil can be introduced from the oil collecting tank 10c to the bearing 52.

[0051] Next, the main effects of this embodiment will be described.

[0052] Figure 3 is a diagram showing a comparative example. Figure 3 10X is shown as a comparative example. The box 10X has a box body 11X provided with a ventilation chamber 10bX and an oil collecting tank 10cX having a different configuration from that of the present embodiment. Figure 3 In FIG. 1 , the first shaft 21 , the second shaft 22 , and the third shaft 33 are schematically indicated by arrows indicating the rotation directions.

[0053] In this example, a ventilation chamber 10bX and an oil collecting tank 10cX are provided in the upper area of ​​the housing 10 between the first shaft 21 and the third shaft 33. The oil collecting tank 10cX is opened toward the oil splashed from the rotating third shaft 33. Therefore, in this example, the oil collecting tank 10cX can be used to directly capture a part of the oil stirred up by the third shaft 33. In addition, the oil stored in the oil collecting tank 10cX can also be used to lubricate the bearing 51 supporting the first shaft 21.

[0054] However, in this example, there is no space for arranging the second shaft 22 in the upper area of ​​the housing 10 between the first shaft 21 and the third shaft 33, so the second shaft 22 has to be immersed in the oil reservoir 10a. As a result, when the device is driven, the stirring resistance acts not only on the third shaft 33 but also on the second shaft 22, and accordingly, the power transmission efficiency is deteriorated. In contrast, the power transmission device 100 of this embodiment is configured as follows.

[0055] (1) The power transmission device 100 includes a housing 10 having an oil reservoir 10a at the bottom, and a first shaft 21, a second shaft 22, and a third shaft 33 axially supported by the housing 10. The first shaft 21 is connected to the rotary electric machine 40. The first shaft 21 includes a first gear portion 211 that outputs power from the rotary electric machine 40. The second shaft 22 includes a second gear portion 221 that receives power from the first gear portion 211 and outputs the input power. The third shaft 33 includes a third gear portion 331 that receives power from the second gear portion 221 and at least partially immerses in the oil reservoir 10a. The housing 10 includes a breather chamber 10b that separates air and oil in the storage chamber S in the housing 10 and communicates with the atmosphere, an oil collecting tank 10c that stores oil stirred up by the third gear portion 331, and an oil guide 10d that guides the oil stirred up by the third gear portion 331 to the oil collecting tank 10c. The breather chamber 10b is provided above and near the third shaft 33. The oil collecting 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 in the casing 10 outside the oil reservoir 10a.

[0056] According to this structure, when power is transmitted from the first shaft 21 to the third shaft 33 via the second shaft 22, the ventilation chamber 10b is provided above and near the third shaft 33, and the oil collecting tank 10c is provided above and near the first shaft 21. Moreover, the oil stirred up by the third gear part 331 is introduced into the oil collecting tank 10c by the oil guide 10d provided above the second shaft 22. Thus, the second shaft 22 can be provided in the upper area in the housing 10 between the first shaft 21 and the third shaft 33, and the second shaft 22 can be arranged outside the oil reservoir 10a. As a result, compared with the case where the second shaft 22 is arranged to be immersed in the oil reservoir 10a, the stirring resistance of the shaft can be reduced, and the stirring resistance of the shaft in the oil reservoir 10a can be improved.

[0057] (2) In the present embodiment, a total of three shafts, namely, the first shaft 21, the second shaft 22, and the third shaft 33, are arranged as power transmission shafts in the housing 10. When the power transmission device 100 is of such a structure, the configuration of the second shaft 22 can improve the stirring resistance that may be generated in the oil reservoir 10a, which is of great technical significance.

[0058] (3) The housing 10 further includes an oil passage 10e for introducing the oil stored in the oil collecting tank 10c into the bearing 51 supporting the first shaft 21. Thus, the oil is not only stored in the oil collecting tank 10c so as to lower the oil level of the oil reservoir 10a when the device is driven, but the stored oil can also be effectively used for lubrication and discharged from the oil collecting tank 10c. Therefore, even when the oil collecting tank 10c is provided above and near the first shaft 21, the oil collecting tank 10c can be used to lower the oil level and lubricate the oil reservoir 10a when the device is driven.

[0059] As mentioned above, the embodiments of the present invention have been described. However, the above embodiments merely show a part of application examples of the present invention, and the technical scope of the present invention is not intended to be limited to the specific structures of the above embodiments.

[0060] Description of Reference Numerals

[0061] 10 Cabinet

[0062] 10a Oil reservoir

[0063] 10b Ventilation chamber

[0064] 10c Oil collecting tank

[0065] 10d Oil guide

[0066] 10e Oil circuit

[0067] 21 First Axis

[0068] 211 First gear unit

[0069] 22 Second axis

[0070] 221 Second gear unit

[0071] 33 Third Axis

[0072] 331 Third gear unit

[0073] 40 Rotating motor (power source)

[0074] 51 bearings (bearings)

[0075] 100 Power transmission device

[0076] S Storage Room

Claims

1. A power transmission device comprising a casing having an oil reservoir at a lower portion, a first shaft, a second shaft, and a third shaft axially supported by the casing, The first shaft is connected to a power source and has a first gear portion for outputting power from the power source. The second shaft has a second gear portion that receives power from the first gear portion and 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 portion of which is immersed in the oil reservoir portion, and is characterized in that: The box has: A ventilation chamber, separating the air and oil in the box body and communicating them with the atmosphere; an oil collecting tank for storing the oil stirred up by the third gear portion; an oil guide member for guiding the oil stirred up by the third gear portion into the oil collecting tank, The ventilation chamber is arranged above and near the third axis, The oil collecting tank is arranged above and near the first shaft, The oil guide is disposed above the second shaft. The second shaft is arranged outside the oil reservoir in the casing.

2. The power transmission device according to claim 1, characterized in that: A total of three shafts, namely, the first shaft, the second shaft, and the third shaft, are arranged in the housing as power transmission shafts.

3. The power transmission device according to claim 1 or 2, characterized in that: The casing further includes an oil passage for introducing the oil stored in the oil collecting tank to a bearing supporting the first shaft.

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