Vehicle drive transmission device

Abstract

The invention relates to a drive transmission device for a vehicle. A main housing (1) is provided with: a specific facing surface (15) that faces in the radial direction (R) a first side surrounding section (51) of a differential housing (40) that surrounds a first side protruding section (5) disposed in a differential gear mechanism (44) so as to protrude toward a first side (L1) in the axial direction with respect to a differential input gear (G34), and that is formed so as to surround the first side surrounding section (51) from the lower side (V2); and a side wall surface (17) formed so as to extend from the end of the specific facing surface (15) on the first side (L1) in the axial direction toward the inside (R1) in the radial direction. An oil retention part (7) in which oil is retained is formed in a space (E) surrounded by the specific facing surface (15), the side wall surface (17), and a surface (49) of the differential input gear (G34) facing the first side (L1) in the axial direction.

Description

Technical Field

[0001] The present invention relates to a vehicle drive transmission device including a differential gear device and a main case that accommodates the differential gear device and oil therein. Background Art

[0002] Japanese Patent Publication No. 2015-178887 discloses a differential gear device (1) in which oil is stored inside a housing (2) that stores a differential gear mechanism (the reference numerals in parentheses in the background art are reference numerals of the referenced document). A differential input gear (12) that inputs a driving force to the differential gear mechanism and a differential housing (10) that rotates integrally with the differential input gear (12) are stored in the housing (2). A pinion gear (15), a pinion gear shaft (14), and a pair of side gears (18, 19) are stored in the differential housing (10). An opening that connects the inside of the differential housing (10) to the outside is formed in the differential housing (10), and lubricating oil is supplied to lubrication target parts such as gears and gear support parts stored in the differential housing (10) through the opening. Specifically, the differential input gear (12) lifts up the oil stored in the housing (2), and the lubricating oil is supplied to the inside of the differential housing (10) through the opening.

[0003] In the case of such a structure, if the oil level inside the housing (2) is high during the rotation of the differential input gear (12), the stirring resistance caused by the oil lifted by the differential input gear (12) becomes larger, and the loss of power transmission in the differential gear device (1) becomes larger. Therefore, in the differential gear device (1) disclosed in the above document, a baffle (30) is arranged in the housing (2). The space in the housing (2) is divided into a first chamber (C1) in which the differential input gear (12) is arranged and a second chamber (C2) located on the opposite side of the differential input gear (12) across the baffle (30). A part of the oil lifted by the differential input gear (12) is stored in the second chamber (C2), the oil level of the oil lifted by the differential input gear (12) drops, and the stirring resistance of the differential input gear (12) is reduced.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2015-178887

[0005] However, when the differential gear device starts to rotate from a stopped state, it takes a certain amount of time until the oil that is lifted reaches the lubricated parts in the differential case. That is, at the beginning of the rotation, the gears and the supporting parts of the gears housed in the differential case may not be supplied with enough oil. For example, when a baffle is provided as in the differential gear device disclosed in the above-mentioned document, the amount of oil at the beginning of the rotation can be increased, so it is possible to increase the amount of oil lifted by the differential input gear and supply more oil to the differential case more quickly. However, when the baffle is provided, the cost of the device increases due to the component cost of the baffle and the assembly cost of assembling the baffle. Summary of the invention

[0006] In view of the above background, it is desired to realize a vehicle drive transmission device that can appropriately supply lubricating oil into a differential case that houses a differential gear mechanism without providing a baffle even in the initial rotational stage when a differential input gear that transmits drive force to the differential gear mechanism starts to rotate from a stationary state.

[0007] In view of the above-mentioned problem, a vehicle drive transmission device is a vehicle drive transmission device including a differential gear device and a main housing that accommodates the differential gear device and oil inside, the differential gear device including: a differential input gear to which the driving force from the driving source of the wheels is transmitted; a differential gear mechanism that distributes the driving force transmitted to the differential input gear to a pair of output members that are respectively connected to the pair of wheels by driving; and a differential housing that is connected to the differential input gear in a manner that rotates integrally and contains the differential gear mechanism, the differential housing including an opening that connects the interior and the exterior of the differential gear mechanism, the direction along the rotation axis of the differential input gear is set as an axial direction, the direction orthogonal to the rotation axis is set as a radial direction, one side of the axial direction is set as an axial first side, and the differential gear mechanism includes a first side protrusion, which is The gear train is configured to have a portion protruding toward the first axial side relative to the differential input gear, and a portion of the differential case surrounding the first side protruding portion is used as a first side surrounding portion. The main case comprises: a specific opposing surface, which is opposed to the first side surrounding portion in the radial direction; and a side wall surface, which is formed to extend from an end of the first axial side of the specific opposing surface toward the inner side of the radial direction. The specific opposing surface is configured to be closer to the inner side in the radial direction than the tooth portion of the differential input gear, and is formed to surround the first side surrounding portion from the lower side. The differential input gear is stopped, and the oil level in the highest state inside the main case is set as a static oil level. The opening is located lower than the static oil level, and an oil retention portion for retaining oil is formed in a space surrounded by the specific opposing surface, the side wall surface, and the surface of the differential input gear facing the first axial side.

[0008] The oil retained in the oil retention portion is not easily affected by the lifting based on the differential input gear. According to this structure, for example, even when the vehicle starts after being stopped for a long time, the oil retained in the oil retention portion can be introduced into the differential case as the differential case rotates, so it is easy to supply lubricating oil to the differential case at the initial stage of rotation when the differential input gear starts to rotate from a stationary state. In addition, since the opening provided in the differential case is located on the lower side than the static oil level, it is also easy to introduce oil from the opening into the interior of the differential case at the initial stage of rotation. When the differential input gear rotates, the oil circulates in the main case by lifting, so the oil level of the oil accumulated in the main case naturally drops. That is, according to this structure, by providing the oil retention portion, even if the height of the oil level is not adjusted using a baffle, lubricating oil can be appropriately supplied to the differential case at the initial stage of rotation, and the stirring resistance of the differential input gear can be reduced after the rotation starts. Thus, according to this structure, a vehicle drive transmission device can be realized without providing a baffle, and lubricating oil can be appropriately supplied to the differential case containing the differential gear mechanism even in the initial rotation period when the differential input gear transmitting the driving force to the differential gear mechanism starts to rotate from a stationary state.

[0009] Further features and advantages of the vehicle drive transmission device will become apparent from the following description of the exemplary and non-limiting embodiments described with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a structural diagram showing an example of a drive transmission device for a vehicle.

[0011] Figure 2 It is a schematic cross-sectional view perpendicular to the axis of the drive transmission device for a vehicle.

[0012] Figure 3 It is a schematic cross-sectional view of the differential gear device when viewed in the axial direction. DETAILED DESCRIPTION

[0013] Hereinafter, an embodiment of a vehicle drive transmission device including a differential gear device and a main case that accommodates the differential gear device and oil will be described based on the accompanying drawings. Figure 1 As shown, the vehicle drive transmission device 100 involved in this embodiment includes a rotary electric machine 2 as a driving force source for a wheel W, an output member (a side gear 43 or a drive shaft 9 described later) drivingly connected to the wheel W, a gear mechanism 6 drivingly connecting the rotary electric machine 2 and the output member, and a main housing 1 for accommodating the rotary electric machine 2 and the gear mechanism 6. Although not shown in the figure, the main housing 1 is divided into at least two storage chambers by a partition wall, and the rotary electric machine 2 is accommodated in one storage chamber and the gear mechanism 6 is accommodated in the other storage chamber.

[0014] The gear mechanism 6 provided in the power transmission path between the rotating electric machine 2 and the output member is configured to include a plurality of gears for drivingly connecting the rotating electric machine 2 and the output member. Figure 1 As shown, in the present embodiment, as a plurality of gears, there are an input gear G23, a countershaft gear mechanism 3, a differential input gear G34, and a differential gear mechanism 44. The differential gear mechanism 44 distributes the driving force transmitted from the rotary electric machine 2 to the differential input gear G34 via a plurality of gears to each of a pair of wheels W via a pair of side gears 43. The pair of side gears 43 is equivalent to an output member. In the present embodiment, the wheels W and the side gears 43 are connected via a drive shaft 9. Therefore, the drive shaft 9 can also be regarded as an output member. In this case, it can also be considered that the pair of side gears 43 of the differential gear mechanism 44 is equivalent to an output member and is included in the gear mechanism 6.

[0015] The rotating electric machine 2 and the input gear G23 are arranged on the first axis A1, and the countershaft gear mechanism 3 is arranged on the second axis A2 which is a different axis parallel to the first axis A1. In addition, the differential input gear G34 and the differential gear mechanism 44 are arranged on the third axis A3 which is a different axis parallel to the first axis A1 and the second axis A2. The drive shaft 9 and the wheel W are also arranged on the third axis A3.

[0016] In addition, in the present application, "drive connection" refers to a state in which two rotating elements are connected in a manner that can transmit a driving force, including a state in which the two rotating elements are connected in a manner that rotates as a whole, or a state in which the two rotating elements are connected in a manner that can transmit a driving force via one or more transmission components. Such transmission components include various components that transmit rotation at the same speed or at a variable speed, such as shafts, gear mechanisms, belts, chains, etc. In addition, as transmission components, engaging devices that selectively transmit rotation and driving force may also be included, such as friction engaging devices, meshing engaging devices, etc.

[0017] The first axis A1, the second axis A2, and the third axis A3 are different imaginary axes, which are arranged parallel to each other as described above. In the following description, the direction parallel to the first axis A1 is set as the axial direction L. Since the first axis A1 and the second axis A2 are parallel to each other, the axial direction L is also a direction parallel to the second axis A2. In addition, since the third axis A3 is also parallel to the first axis A1 and the second axis A2, the axial direction L is also a direction parallel to the third axis A3. In addition, one side of the axial direction L (in the present embodiment, the side on which the rotating motor 2 is arranged relative to the gear mechanism 6) is set as the "axial first side L1", and the opposite side is set as the "axial second side L2".

[0018] In addition, the direction orthogonal to each of the first axis A1, the second axis A2 and the third axis A3 is set as the "radial direction R" based on each axis. In addition, when it is not necessary to distinguish which axis is used as the reference or it is clear which axis is used as the reference, it is sometimes recorded as just "radial direction R". In addition, the direction along the vertical direction when the vehicle drive transmission device 100 is installed on the vehicle is set as the "upper and lower directions V", and the upper side is set as the "upper side V1" and the lower side is set as the "lower side V2". When the vehicle drive transmission device 100 is installed on the vehicle in a state parallel to the horizontal plane, one direction of the radial direction R coincides with the upper and lower directions V. In addition, in the following description, the terms regarding the direction, position, etc. of each component are concepts that also include states with differences caused by allowable errors in manufacturing.

[0019] The rotating electric machine 2 is a rotating electric machine (Motor / Generator) that operates by multi-phase AC (for example, 3-phase AC) and can function as a motor or a generator. The rotating electric machine 2 receives power supply from a DC power supply (not shown) to perform power operation, or supplies power generated by the inertial force of the vehicle to the DC power supply (regeneration). The rotating electric machine 2 has a stator 23 fixed to the main housing 1, and a rotor 21 rotatably supported on the inner side of the radial direction R of the stator 23. The stator 23 includes a stator core and a stator coil 25 wound on the stator core, and the rotor 21 includes a rotor core and a permanent magnet arranged on the rotor core.

[0020] like Figure 1 As shown, the input gear G23 is connected to the rotor 21 of the rotary electric machine 2 in such a manner that it rotates integrally with the rotor 21. The input gear G23 is connected, for example, to an input shaft connected to the rotor shaft of the rotor 21 in such a manner that it rotates integrally with the rotor shaft. The input gear G23 may be formed integrally with the input shaft on the outer peripheral side of the input shaft, or may be formed by a component separate from the input shaft and connected to the input shaft. In either case, the input gear G23 rotates integrally with the rotor 21. In addition, the input gear G23 is drivingly connected to the countershaft gear mechanism 3.

[0021] The countershaft gear mechanism 3 is arranged on the second shaft A2, and drives and connects the rotating electric machine 2 and the differential gear mechanism 44 via the input gear G23 and the differential input gear G34. In the present embodiment, the countershaft gear mechanism 3 has two gears (a first countershaft gear G31 and a second countershaft gear G32) that are connected by a shaft member (countershaft) and rotate integrally. That is, the countershaft gear mechanism 3 is arranged on the second shaft A2, and has a first countershaft gear G31 that meshes with the input gear G23, and a second countershaft gear G32 that rotates integrally with the first countershaft gear G31 and meshes with the differential input gear G34.

[0022] The differential input gear G34, the differential case 40 and the differential gear mechanism 44 together constitute the differential gear device 4. Figure 3 As shown, the differential gear device 4 is supported by a pair of differential bearings B4 so as to be rotatable relative to the main housing 1. The main housing 1 includes: a main housing 11 having an opening on at least one side of the axial direction L, here on the second axial side L2; and a cover housing 12, which abuts against the main housing 11 from the second axial side L2 in a manner to close the opening. In the present embodiment, a pair of differential bearings B4 are supported by the main housing 11 and the cover housing 12, respectively. The differential input gear G34 is fixed to the support member 45 using a fastening member 46, and the support member 45 is rotatably supported on the main housing 1 through the differential bearing B4. The support member 45 constitutes the differential housing 40. In addition, the differential input gear G34 is not limited to a form in which it is fixed to rotate integrally with the support member 45 using a fastening member 46, and can also be formed integrally with the same member as the support member 45 supported by the differential bearing B4.

[0023] The differential gear mechanism 44 is contained in the differential case 40 and includes a pair of pinion gears 41 and a pair of side gears 43 meshing therewith. The pair of pinion gears 41 and the pair of side gears 43 are both bevel gears, and the differential gear mechanism 44 of the present embodiment is a bevel gear type differential gear mechanism. The differential case 40 is a hollow component that accommodates the pair of pinion gears 41 and the pair of side gears 43. The differential case 40 and the differential input gear G34 are connected in a manner that rotates integrally.

[0024] A pair of pinion gears 41 are arranged to be spaced apart from each other in the radial direction R based on the third axis A3. The pinion shaft 42 is supported by the differential case 40 in a manner that it rotates integrally with the differential case 40, and the pair of pinion gears 41 are mounted on the pinion shaft 42. Each of the pair of pinion gears 41 can rotate (rotate) around the pinion shaft 42 as the center, and can rotate (revolve) around the third axis A3 as the center. A pair of side gears 43 mesh with the pair of pinion gears 41. The pair of side gears 43 are arranged to be spaced apart from each other in the axial direction L with the pinion shaft 42 in a manner that they rotate around the third axis A3 as the rotation axis. As Figure 1 As shown, each side gear 43 is drivingly coupled to each of the pair of drive shafts 9 , and each drive shaft 9 is drivingly coupled to a pair of wheels W, respectively.

[0025] However, the rotating electric machine 2 and the gear mechanism 6 constituting the vehicle drive transmission device 100 are oil-lubricated (also including cooling). Specifically, the unillustrated bearings supporting the above-mentioned rotor shaft, input shaft, and auxiliary shaft, the differential bearing B4, the differential gear mechanism 44 housed in the differential case 40, the stator coil 25 of the rotating electric machine 2, etc. are oil-lubricated and cooled. Hereinafter, they are appropriately collectively referred to as lubrication target parts. The lubricating oil can be supplied by an unillustrated mechanical oil pump driven by one or more driving power sources of the wheels W (the above-mentioned rotating electric machine 2, including the internal combustion engine when an internal combustion engine is also provided) as a driving power source, and an unillustrated electric oil pump driven by a driving power source different from the driving power source of the wheels W (for example, a rotating electric machine (motor) different from the rotating electric machine 2). In addition, after lubricating a portion of the lubrication target parts, the oil that has fallen due to gravity and accumulated in the main housing 1 (the oil tank at the bottom of the main housing 1) can be lifted up by a rotating component housed in the main housing 1, or the oil can be blown away by centrifugal force, thereby supplying oil to other lubrication target parts.

[0026] For example, by introducing the oil lifted by the differential input gear G34 into the differential case 40 from the opening 48 formed in the differential case 40, the gears included in the differential case 40 and constituting the differential gear mechanism 44 can be lubricated. However, when the differential gear device 4 starts to rotate from a stopped state, it takes a certain amount of time until the oil lifted by the differential input gear G34 reaches the differential gear mechanism 44 in the differential case 40. That is, in the initial stage of rotation, the oil may not be sufficiently supplied to the supporting components such as the gears and bearings housed in the differential case 40. For example, when the vehicle is started after being stopped for a relatively long time, the differential gear mechanism 44 may not be sufficiently lubricated shortly after the start. In particular, when the outside temperature is low and the viscosity of the oil is high, it is difficult to guide the oil to the opening 48 of the differential case 40, and it is difficult to supply the oil to the differential gear mechanism 44 included in the differential case 40. The vehicle drive transmission device 100 of the present embodiment has a structure that can appropriately supply lubricating oil into the differential case 40 that houses the differential gear mechanism 44 even in the initial stage of rotation when the differential input gear G34 that transmits drive force to the differential gear mechanism 44 starts to rotate from a stationary state.

[0027] As described above, the differential gear device 4 includes: a differential input gear G34 to which the driving force from the driving source (here, the rotary electric machine 2) of the wheels W is transmitted; a differential gear mechanism 44 that distributes the driving force transmitted to the differential input gear G34 to a pair of output members (here, the side gears 43) respectively connected to the pair of wheels W for driving; and a differential case 40 that is connected to the differential input gear G34 in a manner that rotates integrally and contains the differential gear mechanism 44. In addition, the differential case 40 includes an opening 48 that connects the inside and the outside where the differential gear mechanism 44 is arranged. In addition to the openings on both sides of the axial direction L (here, the openings for inserting the drive shaft 9), the differential case 40 is also formed with the opening 48. The opening 48 is formed in the middle part of the axial direction L of the differential case 40.

[0028] like Figure 3 As shown, the differential gear mechanism 44 includes a first side protrusion 5, which is a portion configured to protrude toward the axial first side L1 relative to the differential input gear G34. That is, in the present embodiment, at the configuration position of the differential gear mechanism 44 in the axial direction L, the differential input gear G34 is configured to be offset toward the axial second side L2. The differential case 40 is connected to the differential input gear G34 on the axial second side L2, and the first side protrusion 5 of the differential gear mechanism 44 is enclosed in the differential case 40 on the axial first side L1 relative to the differential input gear G34. Here, the portion of the differential case 40 that surrounds the first side protrusion 5 is referred to as a first side enclosing portion 51.

[0029] In addition, in the main housing 1, the surface opposing the first side surrounding portion 51 in the radial direction R is referred to as a specific opposing surface 15, and the surface extending from the end of the axial first side L1 of the specific opposing surface 15 toward the radial inner side R1 is referred to as a side wall surface 17. That is, the main housing 1 includes a specific opposing surface 15 opposing the first side surrounding portion 51 in the radial direction R, and a side wall surface 17 extending from the end of the axial first side L1 of the specific opposing surface 15 toward the radial inner side R1. Here, the surface of the differential input gear G34 facing the axial first side L1 is referred to as the axial first side opposing surface 49 of the differential input gear G34. Figure 3 As shown, when the differential input gear G34 is fastened and fixed relative to the differential case 40 (here, the support member 45) by inserting the fastening member 46 from the axial first side L1 toward the axial second side L2, the head of the fastening member 46 is also included in the axial first side facing surface 49. Figure 2 and Figure 3 As shown in FIG. 1 , the specific facing surface 15 is arranged at the radially inner side R1 than the tooth portion 4t of the differential input gear G34. Figure 2 The specific facing surface 15 is formed in an arc shape so as to surround the first side surrounding portion 51 from the lower side V2.

[0030] Here, if Figure 2 and Figure 3 As shown in FIG. 1 , the differential input gear G34 is stopped, and the oil level in the main housing 1 at the highest state is set as the static oil level P0. When the oil level is the static oil level P0, as shown in FIG. Figure 3 As shown in FIG. 1 , the opening 48 of the differential case 40 is located below the static oil level. It is sufficient that at least a portion of the opening 48 is located below the static oil level P0. Therefore, when the oil level is the static oil level P0, the oil is retained in the space E surrounded by the specific facing surface 15, the side wall surface 17, and the surface of the differential input gear G34 facing the axial first side L1, that is, the axial first side facing surface 49. That is, the oil retaining portion 7 for retaining the oil is formed in the space E surrounded by the specific facing surface 15, the side wall surface 17, and the axial first side facing surface 49 of the differential input gear G34.

[0031] The oil retained in the oil retaining portion 7 can enter the inside of the differential case 40 regardless of the lifting of the differential input gear G34. For example, even when the vehicle starts after being stopped for a long time, even when the ambient temperature is low and the viscosity of the oil is high, the oil retained in the oil retaining portion 7 can be introduced into the differential case 40 as the differential case 40 rotates. Therefore, even in the initial stage of rotation when the differential input gear G34 starts to rotate from a stationary state, it is easy to supply lubricating oil into the differential case 40.

[0032] In addition, the opening 48 provided in the differential case 40 is located at the lower side V2 than the static oil level P0, so that it is easy to introduce oil from the opening 48 into the inside of the differential case 40 at the beginning of rotation. In addition, when the differential input gear G34 rotates, the oil that is lifted up circulates in the main case 1, so the oil level of the oil accumulated in the main case 1 naturally drops. Therefore, after the rotation starts, the stirring resistance of the differential input gear G34 can be reduced. That is, even if the amount of oil is not adjusted by dividing the main case 1 using other components, lubricating oil can be appropriately supplied to the differential case 40 at the beginning of rotation, and the stirring resistance of the differential input gear G34 can be reduced after the rotation starts. There is no need for other components for dividing the main case 1 and components for installing the other components, and there is no need for work hours for installation.

[0033] Furthermore, if the differential input gear G34 rotates, the oil lifted by the differential input gear G34 is also introduced into the inside of the differential case 40, so the oil does not need to be retained in the oil retention portion 7. In the initial stage of rotation when the differential input gear G34 starts to rotate from a stationary state, the oil can be retained in the oil retention portion 7. Therefore, even if the oil is retained in the oil retention portion 7 in the state of the static oil level P0, when the differential input gear G34 and the differential case 40 start to rotate, the amount of oil gradually decreases, and the retained oil becomes zero as time passes, there is no problem. For example, as described later, by limiting the amount of oil flowing out of the oil retention portion 7, the oil retained in the oil retention portion 7 can be gradually reduced. Thus, the oil retention portion 7 can be configured so that the oil is temporarily retained from the state where the oil is at the static oil level P0.

[0034] like Figure 3 As shown in FIG. 1 , a gap D is provided between the end portion (axial second side end portion 15t) on the axial second side L2 of the specific facing surface 15 and the axial first side facing surface 49 of the differential input gear G34. Therefore, when the differential input gear G34 rotates and the oil level of the oil stored in the main housing 1 drops from the static oil level P0 and becomes lower than the specific facing surface 15, the oil retained in the oil retaining portion 7 flows out from the gap D toward the radial outer side R2. The gap D can be set to function as a throttling portion in the flow path of the oil to flow from the oil retaining portion 7 toward the radial outer side R2. By making the gap D between the specific facing surface 15 and the axial first side facing surface 49 of the differential input gear G34 function as a throttling portion, the oil to be introduced into the differential case 40 can be retained in the oil retaining portion 7 at the initial stage of rotation, and the oil in the oil retaining portion 7 can be gradually reduced after the start of rotation.

[0035] The gap D between the axial second side end 15t of the specific facing surface 15 and the axial first side facing surface 49 of the differential input gear G34 (specifically, the size of the gap D in the axial direction L) can be set to a size obtained by adding the maximum value of the error of the position (the position in the axial direction L) where the axial second side end 15t is arranged in the main housing 1, the maximum value of the error of the assembly position (assembly position in the axial direction L) of the differential input gear G34, and the maximum value of the amplitude of the differential input gear G34 in the axial direction L. Here, the error of the assembly position of the differential input gear G34 is the error of the position where the differential input gear G34 is arranged in a state where it is assembled in the vehicle drive transmission device 100, and includes both the error caused by the assembly accuracy of the differential input gear G34 and the error of the shape (dimension) of the differential input gear G34.

[0036] When the gap D is set in this way, it is easy to avoid interference between the end portion of the specific facing surface 15 on the axial second side L2 (axial second side end portion 15t) and the surface of the differential input gear G34 facing the axial first side L1 (axial first side facing surface 49), and reduce the gap D. In addition, the gap D can be made to function appropriately as a throttling portion in the flow path of the oil to flow from the oil retaining portion 7 to the radial outer side R2. That is, when the gap D is set in this way, the throttling portion can be appropriately provided.

[0037] In addition, as described above, the specific facing surface 15 is arranged on the radially inner side R1 than the tooth portion 4t of the differential input gear G34, and is formed to surround the first side surrounding portion 51 from the lower side V2. In addition, the specific facing surface 15 has a protruding surface 16, which is curved and protruded toward the radially inner side R1 in the direction of the third axis A3, which is the rotation axis of the differential input gear G34, that is, on one side of the circumferential direction C. Specifically, the direction in which the differential case 40 rotates during the normal rotation of the wheel W is defined as the circumferential normal rotation side C1, and the protruding surface 16 is provided on the circumferential normal rotation side C1 of the specific facing surface 15 (refer to Figure 2 That is, the main housing 1 includes a protruding surface 16 formed to protrude from an end portion of the specific facing surface 15 on the circumferential normal rotation side C1 toward the radial inner side R1.

[0038] According to this structure, the flow of the oil that is dragged by the first side surrounding portion 51 of the differential case 40 and is about to rotate with the differential case 40 toward the circumferential positive rotation side C1 is easily restricted by the protruding surface 16, and the amount of oil remaining in the oil retaining portion 7 is ensured. Therefore, the oil accumulated in the oil retaining portion 7 is easily introduced into the interior of the differential case 40 through the opening 48 provided in the differential case 40, and the differential gear mechanism 44 contained in the differential case 40 is easily lubricated appropriately.

[0039] In addition, in this embodiment, if Figure 3 As shown, the specific facing surface 15 is provided so as to overlap with the tooth portion 4t of the differential input gear G34 when viewed in the radial direction along the radial direction R. Specifically, the portion of the specific facing surface 15 on the axial second side L2 is provided so as to overlap with the portion of the tooth portion 4t on the axial first side L1 when viewed in the radial direction. Thus, it is easy to ensure the tooth width of the differential input gear G34 and reduce the gap D between the specific facing surface 15 and the surface (axial first side facing surface 49) of the differential input gear G34 facing the axial first side L1. Therefore, it is easy to make the gap D between the end portion (axial second side end portion 15t) of the specific facing surface 15 on the axial second side L2 and the surface (axial first side facing surface 49) of the differential input gear G34 facing the axial first side L1 function as a throttling portion in the flow path of the oil to be flowed from the oil retaining portion 7 to the radial outer side R2. That is, by configuring in this way, it is possible to ensure the tooth width of the differential input gear G34 and appropriately provide the throttling portion.

[0040] like Figure 2 As shown, in this embodiment, a collecting groove 8 is provided, and the collecting groove 8 receives and temporarily stores the oil in the main housing 1 that is lifted up and scattered by the differential input gear G34. The collecting groove 8 is formed in a space surrounded by a rib 81 and a wall surface that protrudes from the wall surface of the main housing 1 in the axial direction L. The oil stored in the collecting groove 8 is guided to an oil passage (not shown) formed in the main housing 1 through a communicating hole 83 opened in the collecting groove 8, and lubricates the rotor shaft, the input shaft, the counter shaft, the input gear G23, the first counter shaft gear G31, the second counter shaft gear G32, etc. through the oil passage.

[0041] The differential input gear G34 lifts up oil, and the lifted up oil circulates in the main housing 1, thereby reducing the amount of oil accumulated at the bottom of the main housing 1. Therefore, the oil level at the bottom of the main housing 1 is lower than the static oil level P0. By providing a collection tank 8, the time required for the oil lifted up by the differential input gear G34 to return to the lower part of the main housing 1 is prolonged, and the oil level can be further lowered compared to the case where the collection tank 8 is not provided. By lowering the oil level, the stirring resistance of the differential input gear G34 can be reduced. Here, the oil level that changes inside the main housing 1 during the rotation of the differential input gear G34 is set to the dynamic oil level. Figure 2 and Figure 3 , the lowest dynamic oil level P1 is illustrated as the lowest oil level in the dynamic oil level. If the lowest dynamic oil level P1 is located above the tooth portion 4t of the differential input gear G34 by V1, the oil can be lifted by the differential input gear G34. Therefore, the volume of the oil stored in the collection tank 8 is set so that the lowest dynamic oil level P1 does not exceed the lower side V2 of the tooth portion 4t of the differential input gear G34.

[0042] When the differential input gear G34 rotates, as described above, the amount of oil accumulated at the bottom of the main case 1 decreases, and the oil level also decreases. As described above, since the oil also flows out from the oil retention portion 7 through the gap D, the dynamic oil level in the oil retention portion 7 also decreases. In the present embodiment, it is configured that during the rotation of the differential input gear G34, the speed at which the dynamic oil level in the oil retention portion 7 decreases is slower than the speed at which the dynamic oil level around the differential input gear G34 decreases.

[0043] Since part of the oil lifted by the differential input gear G34 is stored in the collection tank 8, the oil level of the oil stored below in the main housing 1 during the rotation of the differential input gear G34, that is, the dynamic oil level, is lower than the static oil level P0. Moreover, as the dynamic oil level drops, the stirring resistance of the differential input gear G34 decreases. According to this structure, the dynamic oil level around the differential input gear G34 becomes lower faster than the dynamic oil level in the oil retention portion 7. That is. The oil retained in the oil retention portion 7 decreases slowly compared to the oil around the differential input gear G34. Therefore, at the initial stage of rotation, sufficient oil can be ensured in the oil retention portion 7, and the oil can be properly introduced into the differential housing 40.

[0044] The oil retained in the oil retaining portion 7 flows out from the oil retaining portion 7 to the radially outer side R2 through the gap D between the end portion (axial second side end portion 15t) of the specific facing surface 15 on the axial second side L2 and the surface (axial first side facing surface 49) of the differential input gear G34 facing the axial first side L1. On the other hand, during the rotation of the differential input gear G34, the oil lifted up by the differential input gear G34 falls and flows into the oil retaining portion 7. During the rotation of the differential input gear G34, when the amount of oil flowing out of the oil retaining portion 7 is greater than the amount of oil flowing into the oil retaining portion 7, the oil retained in the oil retaining portion 7 gradually approaches zero. Therefore, when the rotation of the differential input gear G34 becomes a stable state, the differential gear mechanism 44 enclosed in the differential case 40 can be properly lubricated by the oil lifted up by the differential input gear G34, and the rotation resistance to the differential case 40 caused by the oil in the oil retaining portion 7 can be reduced.

[0045] As described above, according to the present embodiment, a vehicle drive transmission device 100 can be realized, which does not include components such as baffles, and can appropriately supply lubricating oil to the differential case 40 that encloses the differential gear mechanism 44 even in the initial stage of rotation when the differential input gear G34 that transmits driving force to the differential gear mechanism 44 starts to rotate from a stationary state.

[0046] [Other implementation methods]

[0047] In addition, the structure of each embodiment described below is not limited to being applied independently, and can also be applied in combination with the structure of other embodiments as long as no contradiction occurs.

[0048] (1) In the above, a vehicle drive transmission device 100 having a three-axis structure in which the first axis A1, the second axis A2, and the third axis A3 are arranged in parallel is illustrated, but the vehicle drive transmission device 100 may also be a two-axis structure in which the first axis A1 and the second axis A2 are arranged in parallel. In addition, the vehicle drive transmission device 100 may also be a structure in which one or more axes different from the first axis A1, the second axis A2, and the third axis A3 are further arranged in parallel, and more than four axes are arranged in parallel. In addition, the vehicle drive transmission device 100 may also be a single-axis structure in which the rotating electric machine 2, the gear mechanism 6, and the differential gear mechanism 44 are arranged on the same axis.

[0049] (2) In the above, the vehicle drive transmission device 100 is illustrated as including the rotary electric machine 2 as the driving force source of the wheels W, but the driving force source may also be an internal combustion engine. In addition, the vehicle drive transmission device 100 may also be a hybrid drive device including both the internal combustion engine and the rotary electric machine 2 as the driving force sources of the wheels W of the vehicle (for example, various types of hybrid drive devices such as the so-called single motor parallel type and dual motor discrete type).

[0050] (3) In the above, refer to Figure 3 , the differential input gear G34 is arranged on the second axial side L2 of the differential gear device 4, and all the gear units constituting the differential gear mechanism 44 correspond to the first side protrusion 5 that is arranged to protrude toward the first axial side L1 relative to the differential input gear G34. However, the differential gear device 4 may also be a structure in which a part of the gear units constituting the differential gear mechanism 44 is also arranged on the second axial side L2 relative to the differential input gear G34.

[0051] (4) In the above, the main case 1 is provided with the protruding surface 16, which is formed to protrude from the end of the specific facing surface 15 on the circumferential positive rotation side C1 toward the radial inner side R1. However, the main case 1 may also be provided with a second protruding surface, which is formed to protrude from the end of the specific facing surface 15 on the circumferential reverse rotation side opposite to the circumferential positive rotation side C1 on the side where the differential case 40 rotates during the reverse rotation of the wheel W, that is, toward the radial inner side R1. In this case, even in the initial stage of the rotation of the differential input gear G34 when the vehicle in a stopped state starts in the direction in which the wheel W reverses, oil can be appropriately introduced into the differential case 40.

[0052] (5) In the above, the main case 1 is provided with the protruding surface 16 and the main case 1 is provided with the protruding surface 16 and the second protruding surface. However, the main case 1 may not be provided with the protruding surface 16 and the second protruding surface. If the main case 1 is provided with the protruding surface 16 and the second protruding surface, it is easy to restrict the flow of the oil that is dragged by the first side surrounding portion 51 of the differential case 40 and rotates with the differential case 40, and to ensure the amount of oil remaining in the oil retention portion 7. However, since the opening 48 of the differential case 40 is located at the lower side V2 than the static oil level P0, there is no case where the oil is not introduced from the opening 48 when the differential case 40 starts to rotate. Therefore, the main case 1 may not be provided with the protruding surface 16 and the second protruding surface.

[0053] (6) In the above, the gap D between the axial second side end portion 15t of the specific opposing surface 15 and the axial first side opposing surface 49 of the differential input gear G34 is set to function as a throttling portion. However, the gap D may not necessarily function as a throttling portion. At least in the first rotation, the oil retained in the oil retention portion 7 is introduced into the differential case 40 even in a small amount. Moreover, at least before the static oil level P0 is lower than the opening 48 of the differential case 40, the oil is also introduced into the differential case 40 from the opening 48. Therefore, it does not prevent the oil from flowing out of the oil retention portion 7 faster than the reduction speed when the throttling portion is provided.

[0054] (7) In the above, the gap D between the axial second side end 15t of the specific facing surface 15 and the axial first side facing surface 49 of the differential input gear G34 is set to a size obtained by adding the maximum value of the error of the position where the axial second side end 15t is arranged in the main case 1, the maximum value of the error of the assembly position of the differential input gear G34, and the maximum value of the amplitude of the axial direction L of the differential input gear G34. When the gap D is set in this way, the throttle portion can be appropriately provided, but the amount of oil outflow from the oil retaining portion 7 is not prevented from increasing, and the gap D can be larger than this.

[0055] (8) In the above, an example is given in which the specific facing surface 15 is provided so as to overlap with the tooth portion 4t of the differential input gear G34 when viewed in the radial direction. This makes it easy to ensure the tooth width of the differential input gear G34, and to reduce the gap D between the specific facing surface 15 and the surface of the differential input gear G34 facing the first axial side L1 (the first axial side facing surface 49), and to appropriately set the function as a throttle portion. However, this does not prevent the outflow of oil from the oil retention portion 7 from increasing, nor does it prevent the specific facing surface 15 from overlapping with the tooth portion 4t of the differential input gear G34 when viewed in the radial direction.

[0056] (9) In the above, an example is given of a method having a collecting groove 8 for temporarily storing a part of the oil lifted by the differential input gear G34, but this does not prevent a method without the collecting groove 8. The oil lifted by the differential input gear G34 is scattered in the main housing 1 and then flows downward, so that the oil level is lower than the static oil level P0 during the rotation of the differential input gear G34. Therefore, the stirring resistance of the differential input gear G34 is reduced by the amount of the oil level drop. As long as there is a structure that can appropriately supply oil to the lubricated object, a method without the collecting groove 8 is also possible.

[0057] (10) In the above, an example is given in which the amount of oil flowing out of the oil retaining portion 7 is greater than the amount of oil flowing into the oil retaining portion 7 during the rotation of the differential input gear G34. However, this does not prevent an example in which the amount of oil flowing out of the oil retaining portion 7 is equal to the amount of oil flowing into the oil retaining portion 7, or an example in which the amount of oil flowing into the oil retaining portion 7 is greater than the amount of oil flowing out of the oil retaining portion 7.

[0058] [Summary of this embodiment]

[0059] The vehicle drive transmission device (100) described above will be briefly summarized below.

[0060] As one embodiment, a vehicle drive transmission device (100) is a vehicle drive transmission device (100) having a differential gear device (4) and a main housing (1) that accommodates the differential gear device (4) and oil therein, wherein the differential gear device (4) comprises: a differential input gear (G34) to which a driving force from a driving source (2) of a wheel (W) is transmitted; a differential gear mechanism (44) that distributes the driving force transmitted to the differential input gear (G34) to a pair of output members (9, 43) that are respectively connected to the pair of wheels (W) in a driving manner; and a differential housing (40) that rotates integrally with the differential gear device (4). The differential case (40) is connected to the differential input gear (G34) in a manner and contains the differential gear mechanism (44). The differential case (40) has an opening (48) that connects the interior and the exterior of the differential gear mechanism (44). The direction along the rotation axis (A3) of the differential input gear (G34) is set as the axial direction (L), the direction orthogonal to the rotation axis (A3) is set as the radial direction (R), and one side of the axial direction (L) is set as the axial first side (L1). The differential gear mechanism (44) has a first side protrusion (5), and the first side protrusion (5) is configured relative to the differential. The part of the differential case (40) surrounding the first side protrusion (5) is a portion of the differential input gear (G34) protruding toward the first axial side (L1), and the part of the differential case (40) surrounding the first side protrusion (5) is used as a first side surrounding portion (51). The main case (1) includes: a specific opposing surface (15) which is opposed to the first side surrounding portion (51) in the radial direction (R); and a side wall surface (17) which is formed to extend from the end of the specific opposing surface (15) on the first axial side (L1) to the inner side (R1) in the radial direction (R), and the specific opposing surface (15) is arranged at a position closer to the tooth portion of the differential input gear (G34). (4t) is close to the inner side (R1) of the radial direction (R), and is formed to surround the first side surrounding portion (51) from the lower side (V2), the differential input gear (G34) is stopped, and the oil level in the highest state inside the main housing (1) is set as a static oil level (P0), the opening (48) is located on the lower side (V2) than the static oil level (P0), and an oil retention portion (7) for retaining oil is formed in a space surrounded by the specific opposing surface (15), the side wall surface (17), and the surface (49) of the differential input gear (G34) facing the first axial side (L1).

[0061] The oil retained in the oil retention portion (7) is not easily affected by the lifting of the differential input gear (G34). According to this structure, for example, even when the vehicle starts after being stopped for a long time, the oil retained in the oil retention portion (7) can be introduced into the differential case (40) as the differential case (40) rotates, so that it is easy to supply lubricating oil into the differential case (40) at the initial stage of rotation when the differential input gear (G34) starts to rotate from a stationary state. In addition, since the opening (48) provided in the differential case (40) is located at the lower side (V2) than the static oil level (P0), it is also easy to introduce oil from the opening (48) into the inside of the differential case (40) at the initial stage of rotation. When the differential input gear (G34) rotates, the oil is lifted and circulated in the main case (1), so the oil level of the oil accumulated in the main case (1) naturally drops. That is, according to this structure, by providing the oil retention portion (7), even if the height of the oil level is not adjusted using a baffle, lubricating oil can be appropriately supplied to the differential case (40) at the initial stage of rotation, and the stirring resistance of the differential input gear (G34) can be reduced after the rotation starts. Thus, according to this structure, a vehicle drive transmission device (100) can be realized that can appropriately supply lubricating oil to the differential case (40) containing the differential gear mechanism (44) even at the initial stage of rotation when the differential input gear (G34) that transmits driving force to the differential gear mechanism (44) starts to rotate from a stationary state without providing a baffle.

[0062] Here, it is preferred that the other side of the above-mentioned axial direction (L) is set as the axial second side (L2), and the gap (D) between the end portion (15t) of the above-mentioned specific opposing surface (15) on the above-mentioned axial second side (L2) and the surface (49) of the above-mentioned differential input gear (G34) facing the above-mentioned axial first side (L1) is set to function as a throttling portion in the flow path of the oil to be flowed from the above-mentioned oil retention portion (7) to the outer side (R2) of the above-mentioned radial direction (7).

[0063] Since a gap (D) is provided between an end portion (15t) on the axial second side (L2) of the specific facing surface (15) and a surface (49) of the differential input gear (G34) facing the axial first side (L1), when the differential input gear (G34) rotates and the oil level of the oil stored in the main housing (1) drops from the static oil level (P0) and becomes lower than the specific facing surface (15), the oil retained in the oil retaining portion (7) flows out from the gap (D) toward the radial outer side (R2). According to this structure, the gap (D) is set to function as a throttling portion in the flow path of the oil to flow from the oil retaining portion (7) to the radial outer side (R2). By making a gap (D) between a specific opposing surface (15) and a surface (49) of a differential input gear (G34) facing an axial first side (L1) function as a throttling portion, oil introduced into a differential case (40) can be retained in an oil retention portion (7) at an initial stage of rotation, and the oil in the oil retention portion (7) gradually decreases after the rotation starts.

[0064] In addition, it is preferred that the direction around the above-mentioned rotation axis (A3) is set as the circumferential direction (C), and the side on which the above-mentioned differential case (40) rotates during the positive rotation of the above-mentioned wheel (W) is set as the circumferential positive rotation side (C1), and the above-mentioned main case (1) also has a protruding surface (16), which is formed to protrude from the end of the above-mentioned circumferential positive rotation side (C1) of the above-mentioned specific opposing surface (15) toward the inner side (R1) of the above-mentioned radial direction (R).

[0065] According to this structure, the flow of oil that is dragged by the first side surrounding portion (51) of the differential case (40) and is intended to rotate together with the differential case (40) toward the circumferential positive rotation side (C1) is easily restricted by the protruding surface (16), and the amount of oil remaining in the oil retention portion (7) is ensured. Therefore, the oil accumulated in the oil retention portion (7) is easily introduced into the interior of the differential case (40) through the opening (48) provided in the differential case (40), and the differential gear mechanism (44) enclosed in the differential case (40) is easily lubricated appropriately.

[0066] Furthermore, it is preferred that the specific facing surface (15) is provided so as to overlap with the tooth portion (4t) of the differential input gear (G34) when viewed in the radial direction along the radial direction (R).

[0067] According to this structure, it is easy to ensure the tooth width of the differential input gear (G34) and reduce the gap (D) between the specific opposing surface (15) and the surface (49) of the differential input gear (G34) facing the first axial side (L1). Therefore, it is easy to make the gap (D) between the end (15t) of the axial second side (L2) of the specific opposing surface (15) and the surface (49) of the differential input gear (G34) facing the first axial side (L1) function as a throttling portion in the flow path of oil to flow from the oil retention portion (7) to the radial outer side (R2). That is, according to this structure, it is possible to ensure the tooth width of the differential input gear (G34) and appropriately provide the throttling portion.

[0068] In addition, it is preferred that the other side of the above-mentioned axial direction (L) is set as the axial second side (L2), and the gap (D) between the end (15t) of the above-mentioned specific opposing surface (15) on the above-mentioned axial second side (L2) and the surface (49) of the above-mentioned differential input gear (G34) facing the above-mentioned axial first side (L1) is set to a size obtained by adding the maximum value of the error of the position of the end (15t) of the above-mentioned axial second side (L2) of the above-mentioned specific opposing surface (15) configured in the above-mentioned main housing (1), the maximum value of the error of the assembly position of the above-mentioned differential input gear (G34), and the maximum value of the amplitude of the above-mentioned axial direction (L) of the above-mentioned differential input gear (G34).

[0069] When the gap (D) is set in this way, it is easy to avoid interference between the end (15t) of the specific opposing surface (15) on the axial second side (L2) and the surface (49) of the differential input gear (G34) facing the axial first side (L1), and reduce the gap (D). In addition, the gap (D) can be made to function appropriately as a throttling portion in the flow path of oil that is to flow from the oil retention portion (7) to the radial outer side (R2). That is, when the gap (D) is set in this way, the throttling portion can be appropriately provided.

[0070] In addition, it is preferred that the vehicle drive transmission device (100) has a collection tank (8) for temporarily storing the oil in the above-mentioned main housing (1), and the oil level that changes inside the above-mentioned main housing (1) during the rotation of the above-mentioned differential input gear (G34) is set as a dynamic oil level, and the descending speed of the above-mentioned dynamic oil level in the above-mentioned oil retention portion (7) is slower than the descending speed of the above-mentioned dynamic oil level around the above-mentioned differential input gear (G34).

[0071] Since part of the oil lifted by the differential input gear (G34) is stored in the collection tank (8), the oil level of the oil stored below in the main housing (1) during the rotation of the differential input gear (G34), that is, the dynamic oil level, is lower than the static oil level (P0). Moreover, as the dynamic oil level drops, the stirring resistance of the differential input gear (G34) decreases. According to this structure, the dynamic oil level around the differential input gear (G34) becomes lower faster than the dynamic oil level in the oil retention portion (7). That is. The oil retained in the oil retention portion (7) decreases slowly compared to the oil around the differential input gear (G34). Therefore, at the initial stage of rotation, sufficient oil can be ensured in the oil retention portion (7), and the oil can be properly introduced into the differential housing (40).

[0072] Furthermore, in the vehicle drive transmission device (100), preferably, during the rotation of the differential input gear (G34), the amount of oil flowing out of the oil retaining portion (7) is greater than the amount of oil flowing into the oil retaining portion (7).

[0073] The oil retained in the oil retaining portion (7) flows out from the oil retaining portion (7) toward the radial outer side (R2) through a gap (D) between an end portion (15t) on the axial second side (L2) of the specific opposing surface (15) and a surface (49) of the differential input gear (G34) facing the axial first side (L1). On the other hand, during the rotation of the differential input gear (G34), the oil lifted by the differential input gear (G34) falls and also flows into the oil retaining portion (7). When the amount of oil flowing out of the oil retaining portion (7) is greater than the amount of oil flowing into the oil retaining portion (7) during the rotation of the differential input gear (G34), the oil retained in the oil retaining portion (7) gradually approaches zero. Therefore, when the rotation of the differential input gear (G34) becomes stable, the oil lifted by the differential input gear (G34) can be used to properly lubricate the differential gear mechanism (44) enclosed in the differential case (40), and the rotation resistance of the differential case (40) caused by the oil in the oil retention portion (7) can be reduced.

[0074] Description of Reference Numerals

[0075] 1...main housing; 2...rotating electric machine (drive source of wheels); 4...differential gear device; 4t...tooth portion; 5...first side protrusion; 7...oil retention portion; 8...collection tank; 9...drive shaft (output member); 15...specific opposing surface; 15t...axial second side end portion (end portion of the above-mentioned axial second side of the specific opposing surface); 16...protruding surface; 17...side wall surface; 40...differential housing; 43...side gear (output member); 44...differential gear mechanism; 48...opening (opening formed in the differential housing to allow oil to flow); 49...axial first side opposing surface (surface of the differential input gear facing the axial first side); 51...first side envelope Surrounding portion; 100...drive transmission device for vehicle; A3...third axis (rotation axis of differential input gear); C...circumferential direction; C1...circumferential positive rotation side; D...gap (gap between the end of the axial second side of the specific opposing surface and the surface of the differential input gear facing the axial first side); E...space (space surrounded by the specific opposing surface, the side wall surface and the surface of the differential input gear facing the axial first side); G34...differential input gear; L...axial direction; L1...axial first side; L2...axial second side; P0...static oil level; R...radial direction; R1...radial inner side (radial inner side); R2...radial outer side (radial outer side); V2...lower side; W...wheel.

Claims

1. A vehicle drive transmission device comprising a differential gear device and a main housing that accommodates the differential gear device and oil, wherein: The differential gear device comprises: a differential input gear to which a driving force from a driving source of wheels is transmitted; a differential gear mechanism that distributes the driving force transmitted to the differential input gear to a pair of output members drivingly connected to the pair of wheels, respectively; as well as a differential case connected to the differential input gear in a manner of integral rotation and containing the differential gear mechanism; The differential case includes an opening that connects the interior where the differential gear mechanism is arranged with the exterior. The direction along the rotation axis of the differential input gear is defined as an axial direction, the direction perpendicular to the rotation axis is defined as a radial direction, and one side of the axial direction is defined as an axial first side. The differential gear mechanism includes a first side protruding portion, the first side protruding portion being a portion configured to protrude toward a first side in the axial direction relative to the differential input gear. The portion of the differential case surrounding the first side protrusion is used as a first side surrounding portion. The main housing includes: a specific facing surface, which is opposite to the first side surrounding portion in the radial direction; and a side wall surface, which is formed to extend from the end of the first axial side of the specific facing surface toward the radial inner side, The specific facing surface is arranged on the inner side of the tooth portion of the differential input gear in the radial direction and is formed to surround the first side surrounding portion from the bottom. The differential input gear is stopped, and the oil level in the main housing is set to be the highest state as a static oil level. The opening is located below the static oil surface. An oil retaining portion in which oil is retained is formed in a space surrounded by the specific opposing surface, the side wall surface, and the surface of the differential input gear facing the first axial side.

2. The vehicle drive transmission device according to claim 1, wherein: The other side of the axial direction is set as the second axial side, A gap between the end portion of the specific opposing surface on the axial second side and the surface of the differential input gear facing the axial first side is set to function as a throttle portion in a flow path of oil that flows from the oil retaining portion to the radially outer side.

3. The vehicle drive transmission device according to claim 1 or 2, wherein: The direction around the rotation axis is defined as the circumferential direction, and the side on which the differential case rotates during the normal rotation of the wheel is defined as the normal rotation side in the circumferential direction. The main housing further includes a protruding surface formed so as to protrude inward in the radial direction from an end portion of the specific opposing surface on the circumferential normal rotation side.

4. The vehicle drive transmission device according to claim 1 or 2, wherein: The specific opposing surface is provided so as to overlap with the teeth of the differential input gear when viewed in the radial direction along the radial direction.

5. The vehicle drive transmission device according to claim 1 or 2, wherein: The other side of the axial direction is set as the second axial side, The gap between the end of the second axial side of the specific opposing surface and the surface of the differential input gear facing the first axial side is set to a size obtained by adding the maximum value of the error of the position of the end of the second axial side of the specific opposing surface configured in the main housing, the maximum value of the error of the assembly position of the differential input gear, and the maximum value of the axial amplitude of the differential input gear.

6. The vehicle drive transmission device according to claim 1 or 2, wherein: A collecting tank for temporarily storing the oil in the main housing is provided. The oil level that changes inside the main housing during the rotation of the differential input gear is defined as a dynamic oil level. A decreasing speed of the dynamic oil surface in the oil stagnation portion is slower than a decreasing speed of the dynamic oil surface around the differential input gear.

7. The vehicle drive transmission device according to claim 1 or 2, wherein: During the rotation of the differential input gear, the amount of oil flowing out of the oil retaining portion is greater than the amount of oil flowing into the oil retaining portion.

Images