transmission

Abstract

A kind of transmission, wherein, transmission unit is housed in the gearbox with oil storage portion in bottom, in transmission unit, differential device is configured in one side of axial, and reducer is configured in the other side of axial, differential box (20) has torso (20a), oil guide inlet (20i) being opened to the one side of torso (20a) in axial direction, and oil discharge outlet (20o) being opened to the other side of torso (20a) in axial direction, when planetary carrier (C) rotates, large-diameter gear portion (P1) that revolves in the same direction is configured so that its lower portion on the orbit of revolution is immersed below from the storage oil surface (f) of the oil storage portion (O) in the bottom of gearbox (10), 1st oil guide portion (G1) is set on gearbox (10) in the manner of extending from the position on the orbit of revolution on the radially outer side to the one side of the axial direction, wherein, 1st oil guide portion (G1) captures the oil that is stirred up by large-diameter gear portion (P1) from oil storage portion (O) by revolution, and guides it to oil guide inlet (20i).Therefore, the storage oil surface height of oil storage portion can efficiently supply the oil stirred up by large-diameter gear portion of planetary gear into differential box even if it is set lower, so as to inhibit the stirring resistance of oil, and improve transmission efficiency.

Description

Technical Field

[0001] The present invention relates to a transmission device, particularly a transmission device in which a transmission unit is housed within a gearbox having an oil reservoir at the bottom, the transmission unit comprising a reducer and a differential device, the reducer being composed of a planetary gear mechanism; a differential housing in the differential device receiving the output of the reducer, wherein the differential device is configured on one side of the axial direction and the reducer is configured on the other side of the axial direction in the transmission unit.

[0002] In this invention and this specification, "axial" refers to the direction along the rotation axis of the transmission unit (the first axis in the embodiment), and "radial" refers to the radial direction of the transmission unit with the rotation axis as its central axis. Background Technology

[0003] The aforementioned transmission devices are known to be disclosed in patent documents such as Patent Document 1 and Patent Document 2. In these transmission devices, in order to supply lubricating oil to the differential, for example, in the transmission device of Patent Document 1, oil is forcibly supplied to the differential by an oil pump; furthermore, in the transmission device of Patent Document 2, the oil stored at the bottom of the gearbox is agitated by the rotation of the differential. At this time, the splashed oil is supplied to the differential through the opening of the differential.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 9-72405

[0007] Patent Document 2: Japanese Patent Application Publication No. 2018-189135 Summary of the Invention

[0008] The problem the invention aims to solve

[0009] However, in the transmission device of Patent Document 1, the presence of a dedicated oil pump increases costs. Furthermore, in the transmission device of Patent Document 2, the rotating differential experiences churning resistance when agitating the stored oil. This churning resistance increases, particularly when the oil level in the transmission is set high, becoming a major cause of reduced transmission efficiency.

[0010] The present invention is proposed in view of the above-described situation, and aims to provide a transmission device that can solve the above problems with a simple structure.

[0011] Problem Solving Methods

[0012] To achieve the above objectives, the present invention relates to a transmission device, characterized in that, in the transmission device, a transmission unit is housed within a gearbox having an oil reservoir at the bottom, wherein the transmission unit includes a reducer and a differential device, the differential housing of the differential device receiving the output of the reducer, the differential device being disposed on one axial side and the reducer being disposed on the other axial side in the transmission unit, the reducer comprising a sun gear, a ring gear, a plurality of planetary gears, and a planet carrier, the ring gear being concentrically disposed and fixed to the gearbox relative to the sun gear; the planetary gears integrally having a large-diameter gear portion meshing with the sun gear and a small-diameter gear portion meshing with the ring gear; the planet carrier supporting the plurality of planetary gears for free rotation, and the planet carrier being integral with the differential housing. The differential has a body, an oil inlet, and an oil outlet. The body can accommodate the differential mechanism and store oil. The oil inlet opens toward one side of the body in the axial direction and communicates with the interior of the body. The oil outlet opens toward the other side of the body in the axial direction and allows the stored oil in the body to be discharged into the gearbox. The large-diameter gear, which revolves in the same direction as the planetary carrier, is configured such that its lower part on the revolution trajectory is submerged below the oil storage surface of the oil reservoir. A first oil guide is provided on the gearbox extending radially outward from the revolution trajectory toward one side of the axial direction. The first oil guide captures the oil stirred up by the large-diameter gear from the oil reservoir during the revolution and guides the captured oil to the oil inlet.

[0013] Furthermore, a second feature of the present invention is that, based on the first feature, the axial position of the oil outlet overlaps with the axial position of at least a portion of the oil storage portion.

[0014] Furthermore, a third feature of the present invention is that, based on the first or second feature, the axial position of the oil outlet overlaps with the axial position of at least a portion of the planetary gear.

[0015] Furthermore, a fourth feature of the present invention is that, based on any one of the first to third features, a first unit support bearing is clamped and installed between the inner peripheral surface of the first protrusion and the outer peripheral surface of the second protrusion, wherein the first unit support bearing is used to support the transmission unit on the gearbox, and the first unit support bearing is located on one side of the axial direction; the first protrusion is formed on the end wall portion of the gearbox on the axial side; the second protrusion protrudes from the outer surface of the side wall of the differential on the axial side; an oil inlet space is defined by an oil seal, the inner peripheral surface of the first protrusion, and the outer surface of the first unit support bearing, wherein the oil inlet faces the oil inlet space. The oil seal seals the outer periphery of the output shaft and the through hole in the end wall through which the output shaft passes. The output shaft is inserted into the second protrusion and rotates in conjunction with the output side of the differential mechanism. The first protrusion has a through hole that connects the oil inlet space and other spaces within the gearbox. The opening position of the downstream end of the first oil guide is set such that oil guided by the first oil guide flows into the oil inlet space through the through hole. An oil supply mechanism is provided between the second protrusion and the output shaft. The oil supply mechanism supplies oil in the space to the body through the oil inlet port in response to the relative rotation between the second protrusion and the output shaft.

[0016] Furthermore, the fifth feature of the present invention is that, based on the fourth feature, the differential gearbox has a planetary gear support portion that supports the planetary gear so that it can rotate freely, the sidewall integrally has a cylindrical portion surrounding the second protrusion, the inner circumference of a member arranged axially adjacent to the planetary gear support portion is fitted and fixed to the outer circumference of the cylindrical portion, a cavity portion is formed between the fitting surfaces of the inner circumference of the member and the outer circumference of the cylindrical portion, the cavity portion communicates with the planetary gear support portion, and a connecting hole is formed in the cylindrical portion to communicate with the inner circumferential surface of the cylindrical portion.

[0017] Furthermore, a sixth feature of the present invention is that, based on any one of the first to fifth features, a second unit support bearing is mounted on the opposing end wall portion of the gearbox opposite to the reducer, wherein the second unit support bearing is used to support the transmission unit on the gearbox, and the second unit support bearing is located on the other side of the axial direction, and the inner surface of the opposing end wall portion is formed approximately along a virtual plane orthogonal to the rotation axis of the transmission unit and passing through the oil reservoir portion, the first oil guide portion includes an oil capturing portion and an oil guiding portion, the oil capturing portion is disposed at a radially outer position on the revolution trajectory and is capable of capturing oil stirred up by the large diameter gear portion, the oil guiding portion extends from the oil capturing portion toward one side of the axial direction and guides the oil captured by the oil capturing portion to the oil inlet or to the periphery of the oil inlet, the second oil guide portion is provided along the inner surface of the opposing end wall portion, wherein the second oil guide portion receives a portion of the oil captured by the oil capturing portion from the oil capturing portion and guides the received oil to the second unit support bearing.

[0018] Furthermore, the seventh feature of the present invention is that, based on any one of the first to sixth features, the differential mechanism comprises a pair of half-shaft gears and a plurality of pinions, the pair of half-shaft gears being arranged facing each other along the axial direction within the body, and the back surfaces of each pair of half-shaft gears being supported in the body in a manner rotatable about the rotation axis of the transmission unit, the plurality of pinions meshing with the pair of half-shaft gears, and the back surfaces of each plurality of pinions being supported in the body in a manner rotatable about a second axis orthogonal to the rotation axis, an oil groove being provided on the inner surface of the differential housing facing the back surface of the half-shaft gear on the other side of the axial direction, the oil groove extending radially outward from the oil outlet and opening into the differential housing on the outer side of the outer periphery of the corresponding half-shaft gear, the opening end of the oil groove opening into the differential housing being positioned such that oil that is scattered from the pinion due to the rotation of the pinion can be introduced.

[0019] In this invention, "the oil level of the oil reservoir" refers to the oil level of the oil reservoir when the transmission device is stationary.

[0020] The effects of the invention

[0021] According to a first feature of the invention, in the transmission, a transmission unit in which a differential is disposed on one side of the axial direction and a planetary gear reducer is disposed on the other side of the axial direction is housed in a gearbox having an oil reservoir at the bottom; the differential housing has a body capable of storing oil, an oil inlet opening on one side of the body in the axial direction, and an oil outlet opening on the other side of the body in the axial direction; the large-diameter gear portion of the planetary gears, which revolves in the same direction when the planetary carrier rotates, is configured such that the lower part of the large-diameter gear portion on the revolution trajectory is submerged below the oil reservoir surface; a first oil guide portion, which captures the oil stirred up from the oil reservoir by the large-diameter gear portion through the revolution and guides it to the oil inlet, is provided on the gearbox in such a way that it extends on one side of the axial direction from a position located radially outward on the revolution trajectory. Therefore, the large-diameter gear, which revolves in conjunction with the rotation of the planetary carrier, not only effectively agitates the oil stored in the oil reservoir, but the agitated oil is also captured by the first oil guide and guided to the oil inlet. This allows for sufficient oil supply to the differential housing's body, and the oil in the body flows back to the oil reservoir within the gearbox through the oil outlet. Thus, even if the oil level in the reservoir is low enough to submerge a portion of the planetary gears (especially the large-diameter gear), the oil agitated by the large-diameter gear can be efficiently supplied to the differential housing. This ensures effective lubrication of the differential mechanism while allowing the oil level to be set low to suppress oil churning resistance, thereby improving transmission efficiency. Furthermore, an oil pump is not required, contributing to cost savings.

[0022] Furthermore, according to the second feature of the invention, the axial position of the oil drain outlet overlaps with the axial position of at least a portion of the oil reservoir. Therefore, the path of oil discharged from the differential through the oil drain outlet back to the oil reservoir of the gearbox can be shortened, thereby enabling the oil to quickly return from the differential to the oil reservoir. This is advantageous when the oil level in the oil reservoir is set at a low level.

[0023] Furthermore, according to a third feature of the invention, the axial position of the oil outlet overlaps with the axial position of at least a portion of the planetary gear. Therefore, when a portion of the oil discharged from the differential box through the oil outlet is dispersed radially outward under the action of centrifugal force generated by the rotation of the planetary carrier, the oil can be effectively used to lubricate the planetary gear.

[0024] Furthermore, according to a fourth feature of the invention, a first unit support bearing is clamped between the inner circumferential surface of the first protrusion and the outer circumferential surface of the second protrusion, wherein the first unit support bearing is used to support the transmission unit on the gearbox, and the first unit support bearing is located on one axial side, the first protrusion is formed on the end wall portion of the gearbox on the axial side, and the second protrusion protrudes from the outer surface of the side wall of the differential on the axial side. An oil inlet space is defined by an oil seal, the inner circumferential surface of the first protrusion, and the outer surface of the first unit support bearing, wherein the oil inlet faces the oil inlet space. The oil seal seals the outer periphery of the output shaft, which is fitted into the second protrusion, and the through hole in the end wall through which the output shaft passes. The first protrusion has a through hole that connects the oil inlet space to other spaces within the gearbox. The opening position of the downstream end of the first oil guide is set so that oil guided by the first oil guide flows into the oil inlet space through the through hole. An oil supply mechanism is provided between the second protrusion and the output shaft. The oil supply mechanism supplies oil in the oil inlet space to the gearbox body through the oil inlet port in response to the relative rotation between the second protrusion and the output shaft. Thus, by utilizing the oil supply mechanism based on the relative rotation between the second protrusion and the output shaft, oil flowing out of the first oil guide and guided into the oil inlet space can be efficiently supplied to the rotating differential gearbox through the oil inlet port. Furthermore, the oil accumulated in the oil inlet space can be used to efficiently lubricate the first unit support bearing.

[0025] Furthermore, according to a fifth feature of the invention, the sidewall of the differential gearbox on one axial side integrally has a cylindrical portion surrounding the second protrusion. The inner circumference of a member arranged axially adjacent to the planetary gear support is fitted and fixed to the outer circumference of the cylindrical portion. A cavity communicating with the planetary gear support is formed between the mating surfaces of the inner circumference of the member and the outer circumference of the cylindrical portion. A connecting hole is formed in the cylindrical portion to communicate with the inner circumferential surface of the cylindrical portion. Thus, oil reaching the first unit support bearing via the first oil guide and the aforementioned space, after lubricating the first unit support bearing, flows along the sidewall of the differential gearbox and reaches the inner circumferential surface of the cylindrical portion by centrifugal force. This oil flows through the connecting hole to the cavity and from the cavity to the planetary gear support, thereby lubricating the support.

[0026] Furthermore, according to a sixth feature of the invention, a second unit support bearing for supporting the transmission unit on the gearbox and located on the opposite side of the axial direction is mounted on the opposing end wall portion of the gearbox opposite to the reducer, and the inner side surface of the opposing end wall portion is formed approximately along a virtual plane orthogonal to the rotation axis of the transmission unit and passing through the oil reservoir portion. The first oil guide portion includes an oil capturing portion and an oil guiding portion. The oil capturing portion is disposed at a radially outer position on the revolution trajectory of the large diameter gear portion and is capable of capturing oil stirred up by the large diameter gear portion. The oil guiding portion extends from the oil capturing portion toward one side of the axial direction and guides the oil captured by the oil capturing portion to the oil inlet or to the periphery of the oil inlet. The second oil guiding portion is provided along the inner side surface of the opposing end wall portion, wherein the second oil guiding portion receives a portion of the oil captured by the oil capturing portion from the oil capturing portion and guides the received oil to the second unit support bearing. Therefore, the second oil guide section can receive a portion of the oil captured by the oil capturing section of the first oil guide section and guide the oil to the second unit support bearing provided on the aforementioned opposed end wall of the gearbox, thereby efficiently lubricating the second unit support bearing. Furthermore, the inner surface of the aforementioned opposed end wall where the second oil guide section is located is arranged approximately along a virtual plane orthogonal to the rotation axis of the transmission unit and passing through the oil reservoir. Therefore, the oil lubricating the second unit support bearing flows approximately vertically downwards along the inner surface of the opposed end wall and quickly reaches the gearbox's oil reservoir. This is advantageous when the oil level in the oil reservoir is set relatively low.

[0027] Furthermore, according to the seventh feature of the present invention, in the differential device, an oil groove is provided on the inner surface of the differential housing facing the back of the half-shaft gear located on the other side of the axial direction. The oil groove extends radially outward from the oil outlet and opens into the differential housing on the outer side of the outer periphery of the corresponding half-shaft gear. The opening end of the oil groove that opens into the differential housing is positioned such that oil that is scattered from the pinion due to the rotation of the pinion can be introduced. Therefore, the oil groove can efficiently deliver oil to the oil outlet by utilizing the flow energy of the oil that is scattered from the pinion in the differential housing. Attached Figure Description

[0028] Figure 1 This is an overall longitudinal sectional view showing the transmission device according to the first embodiment of the present invention. (First Embodiment)

[0029] Figure 2 yes Figure 1 A cross-sectional view along line 2-2. (First Embodiment)

[0030] Figure 3 yes Figure 1 A cross-sectional view along line 3-3. (First Embodiment)

[0031] Figure 4 yes Figure 1A cross-sectional view along line 4-4. (First Embodiment)

[0032] Figure 5 This is a perspective view of the main body of the transmission unit. (First Embodiment)

[0033] Figure 6 This is a side view of the second housing of the differential gearbox and the pinion (dashed line), viewed from the axial inside. (First Embodiment)

[0034] Figure 7 This is a perspective view of the second housing unit, viewed from the axial inner side and obliquely upward. (First Embodiment)

[0035] Figure 8 This is a perspective view showing an example of a configuration in which a first oil guide portion and a second oil guide portion are provided on the inner surface of the gearbox. (First Embodiment)

[0036] Figure 9 This is a side view of the first housing of the differential gearbox, viewed from the axial inside. (First Embodiment)

[0037] Figure 10 This illustrates the transmission device of the second embodiment. Figure 2 Corresponding sectional view. (Second Embodiment)

[0038] Figure 11 The second housing in the second embodiment and Figure 7 The corresponding three-dimensional diagram. (Second embodiment)

[0039] Figure 12 The transmission device shown in the third embodiment is... Figure 2 Corresponding sectional view. (Third embodiment)

[0040] Figure 13 This is a perspective view showing the differential box according to the third embodiment. (Third Embodiment)

[0041] Figure 14 This is a perspective view of the second housing unit of the third embodiment, viewed from the inner axial direction and from an obliquely upward perspective.

[0042] (Third Implementation)

[0043] Explanation of reference numerals in the attached figures

[0044] A……Transmission device

[0045] Bc1……Unit 1 Support Bearing

[0046] Bc2……Unit 2 Support Bearing

[0047] Bp2... The second bearing for planetary gears, serving as a support for the planetary gears.

[0048] C... Planetary Carrier

[0049] D……Differential device

[0050] G1...First Oil Guiding Section

[0051] G2...Second Oil Guiding Section

[0052] f……Storage oil surface

[0053] O……Oil Storage Department

[0054] OS1...the No. 1 oil supply organization

[0055] OS2...the second oil supply organization as an oil supply organization.

[0056] P... Planetary Gears

[0057] P1……Large Diameter Gear Section

[0058] P2……Small Diameter Gear Section

[0059] R……Reducer

[0060] U……Transmission Unit

[0061] X1……The first axis as the axis of rotation

[0062] X2……Second axis

[0063] 10……Transmission

[0064] 11b……The protrusion that serves as the first protrusion

[0065] 20b……The protrusion as the second protrusion

[0066] 11bh... Through hole

[0067] 11s……The first end wall portion as one side of the axial direction

[0068] 11sh……Through hole

[0069] 12s……The second end wall as the opposing end wall

[0070] 14... Oil Seal

[0071] 16... Oil introduction space

[0072] 20……Differential box

[0073] 20as……sidewall

[0074] 20At……Cylindrical section

[0075] 20a……Tortoise

[0076] 20i... Oil inlet

[0077] 20o……oil discharge outlet

[0078] 21... Differential gear mechanism as a differential mechanism

[0079] 23... small gear

[0080] 24... Half-shaft gear

[0081] 26……oil tank

[0082] 26i……Open end of the oil tank

[0083] 31...Sun Gear

[0084] 32……ring gear

[0085] 40... Oil Capture Department

[0086] 41...The 1st Oil Guidance Department of the Oil Guidance Department

[0087] 52……The second output shaft as the output shaft

[0088] 55……Parking gear as a component

[0089] 56……Cavity

[0090] 57……Connecting holes Detailed Implementation

[0091] First, refer to Figures 1-9 The first embodiment will be described.

[0092] Implementation Method 1

[0093] exist Figure 1 In this transmission device A installed in a vehicle such as an automobile, there are: a gearbox 10 fixedly supported by a support 13 (e.g., the vehicle body), and a single transmission unit U housed and supported within the gearbox 10. The bottom of the gearbox 10 functions as an oil reservoir O, which can store lubricating oil at a predetermined oil level f when the transmission unit U is stationary.

[0094] The transmission unit U is a unified unit that integrates the reducer R and the differential D. The reducer R is composed of a planetary gear mechanism that reduces and transmits power from a power source (not shown) (e.g., an onboard electric motor). The differential D allows the first output shaft 51 and the second output shaft 52 to rotate differentially and distributes and transmits the output of the reducer R to the first output shaft 51 and the second output shaft 52. Furthermore, in the transmission unit U, the planet carrier C of the reducer R and the differential D rotate integrally about a first axis X1. Moreover, the first output shaft 51 and the second output shaft 52 cause the left and right drive wheels to rotate in tandem via a linkage mechanism (not shown).

[0095] In the transmission unit U, the differential device D is biased towards one side of the axial direction. Figure 1 (The same applies in the following description) and the reducer R is positioned on the right side of the axis (as described below), and the reducer R is biased towards the other side of the axis ( Figure 1 The configuration is as follows (the left side of the text, and the same applies in the following instructions).

[0096] The gearbox 10 is configured to be divided along the axial direction into, for example, a cylindrical housing body 11 having a bottom and a cover 12 that closes the open end of the housing body 11. The housing body 11 is formed such that the diameter of its body 11a gradually (in a partially staged manner in the example drawing) decreases with the first end wall portion 11s near the axial side.

[0097] The first end wall portion 11s forms a sidewall of the gearbox 10, and has an axially extending through hole 11sh at its center. Furthermore, a protrusion 11b is integrally formed on the first end wall portion 11s around the through hole 11sh. The protrusion 11b is cylindrical and extends axially inward. The middle portion of the second output shaft 52 is inserted into the through hole 11sh via an oil seal 14. The protrusion 11b is an example of a first protrusion. Alternatively, the protrusion 11b may also protrude axially outward from the first end wall portion 11s.

[0098] On the other hand, the cover 12 has a second end wall portion 12s as its main body. The second end wall portion 12s is disc-shaped and is detachably connected to the open end of the housing body 11 by a plurality of bolts B1. The cover 12 forms another side wall of the gearbox 10. Furthermore, the center of the second end wall portion 12s has an axially extending through hole 12sh. Around the periphery of this through hole 12sh, a protrusion 12b is integrally formed on the second end wall portion 12s. The protrusion 12b is cylindrical and extends axially outward. The second end wall portion 12s is an example of an opposing end wall portion opposite to the reducer R. Moreover, the outer periphery of the second end wall portion 12s is detachably fixed to the aforementioned support portion 13 by a plurality of bolts B2.

[0099] Most of the transmission unit U is supported at the first end wall 11s and the second end wall 12s of the gearbox 10 via the first unit support bearing Bc1 and the second unit support bearing Bc2, in a manner that allows it to rotate freely about the first axis X1. Moreover, the first axis X1 is the axis of rotation of the transmission unit U, which coincides with the axis of rotation of the differential gearbox 20 and the planetary carrier C, as described later.

[0100] Furthermore, with the cover 12 removed from the housing body 11, the transmission unit U can be inserted into and assembled into the housing body 11 from the axial outside via the open end of the housing body 11.

[0101] The following mainly refers to Figure 1 and Figure 2 Here is a specific example of the differential device D. The differential device D includes a differential housing 20 and a differential gear mechanism 21. The differential housing 20 receives rotational force from the reducer R, and the differential gear mechanism 21 is housed in a mechanism chamber inside the differential housing 20.

[0102] The differential housing 20 includes a first housing 20A, which is open at one end and formed into a generally bowl-shaped body, and a second housing 20B, which is a closed annular shape capable of opening and closing the open end of the first housing 20A. The first housing 20A integrally has a body 20a and a bearing protrusion 20b. The body 20a is the main body of the differential housing 20, and the bearing protrusion 20b is cylindrical and extends axially outward from the side wall 20as of the body 20a. The bearing protrusion 20b is an example of the second protrusion, and the aforementioned first unit support bearing Bc1 is sandwiched between the outer peripheral surface of the bearing protrusion 20b and the inner peripheral surface of the protrusion 11b of the housing body 11, which serves as the first protrusion.

[0103] An annular oil inlet space 16 surrounding the second output shaft 52 is defined by the oil seal 14 that seals between the outer periphery of the second output shaft 52 and the through hole 11sh of the first end wall portion 11s, the inner peripheral surface of the protrusion 11b, and the outer surface of the first unit support bearing Bc1. An oil inlet 20i, formed by the outer end opening of the bearing protrusion 20b, is opposite to this oil inlet space 16. At the oil inlet 20i, oil flowing within the gearbox 10 (particularly the oil captured and guided by the first oil guide portion G1, as described later) can be effectively introduced into the body 20a of the differential case 20.

[0104] Furthermore, the protrusion 11b has a through hole 11bh in the shape of a cut, which traverses the protrusion 11b to connect the interior and exterior of the protrusion 11b (thus connecting the oil inlet space 16 and other spaces within the gearbox 10). Figure 2(Refer to). Furthermore, the opening position of the downstream end of the first oil guide G1 (the second guide groove portion 412 of the first oil guide 41 described later) is set such that oil guided by the first oil guide G1 flows into the oil inlet space 16 after passing through the through hole 11bh. For example, in one embodiment, an example is shown where the downstream end of the first oil guide G1 passes through the through hole 11bh, and the opening end of this downstream end is located within the oil inlet space 16. In this case, oil flows directly from the first oil guide G1 into the oil inlet space 16.

[0105] In contrast, a modified version can be implemented where the opening end of the downstream end of the first oil guide G1 is located in the middle of the through hole 11bh. In this case, the oil flowing out of the first oil guide G1 flows through the through hole 11bh and also flows into the oil inlet space 16. Alternatively, if the opening end of the downstream end of the first oil guide G1 is located at a position where oil flowing out of the through hole 11bh can flow into the through hole 11bh even if it is outside the through hole 11bh (for example, if the opening end is above the through hole 11bh and downstream of the flow direction of the oil flowing out of the opening end), the oil flowing out of the opening end will also flow through the through hole 11bh and into the oil inlet space 16.

[0106] The body 20a of the first housing 20A has no openings or working windows on its peripheral walls, thus allowing lubricating oil to be stored inside the body 20a.

[0107] Furthermore, the inner surface of the outer periphery of the body 20a is formed into a spherical shape, a portion of which forms a pinion support surface 20pf. On the other hand, the inner surface of the sidewall 20as has a first half-shaft gear support surface 20sf1 and an annular recess 20st. The first half-shaft gear support surface 20sf1 is formed into an annular plane orthogonal to the first axis X1, and the annular recess 20st is connected to the inner periphery of the first half-shaft gear support surface 20sf1.

[0108] The rear side protrusion of the half-shaft gear 24, described later, fits into the annular recess 20st. Furthermore, as... Figure 9 As shown, the inner surface of the body 20a is provided with a plurality of half-shaft gear lubricating oil grooves 19, which extend in a manner that traverses the first half-shaft gear support surface 20sf1 and the annular recess 20st.

[0109] In addition, such as Figure 5As shown, a pair of arc-shaped guide protrusions 20bt are provided on the outer end face of the bearing protrusion 20b, and the pair of guide protrusions 20bt are spaced apart in the circumferential direction. In addition, on the inner circumferential surface of the bearing protrusion 20b, a pair of axially extending guide grooves 20bg are recessed corresponding to one end and the other end of each guide protrusion 20bt in the circumferential direction. The inner ends of these guide grooves 20bg communicate with the inner circumferential end of the half-shaft gear lubricating oil groove 19, so that a portion of the oil supplied to the body 20a via the guide grooves 20bg can be efficiently supplied to the half-shaft gear lubricating oil groove 19 (and further to the rotating sliding part of the half-shaft gear 24).

[0110] Each guide protrusion 20bt has a first guide surface g1 and a second guide surface g2 at one end and the other end in the circumferential direction, respectively. When the bearing protrusion 20b and the second output shaft 52 rotate relative to each other, especially when the second output shaft 52 rotates at a low speed relative to the bearing protrusion 20b, the first guide surface g1 guides the oil stored in the oil inlet space 16 around the outer end of the bearing protrusion 20b into the corresponding guide groove 20bg. Especially when the second output shaft 52 rotates at a high speed relative to the bearing protrusion 20b, the second guide surface g2 guides the oil in the oil inlet space 16 into the corresponding guide groove 20bg.

[0111] Furthermore, the first guide surface g1, together with its corresponding guide groove 20bg, forms the first oil supply mechanism OS1. The first oil supply mechanism OS1, in response to the aforementioned relative rotation, supplies oil from the oil inlet space 16 to the body section 20a via the oil inlet 20i. Additionally, the second guide surface g2, together with its corresponding guide groove 20bg, forms the second oil supply mechanism OS2. The second oil supply mechanism OS2, in response to the aforementioned relative rotation, supplies oil from the oil inlet space 16 to the body section 20a via the oil inlet 20i.

[0112] In addition, such as Figure 1 As shown, the guide groove 20bg extends axially and is formed at an angle, with its width gradually widening towards the axial inward side of the differential housing 20. In this case, the oil flowing into the guide groove 20bg adheres to the groove wall surface due to the centrifugal force generated by the rotation of the planetary carrier C (i.e., the differential housing 20). Moreover, through the action of this centrifugal force, the oil adhering to the groove wall surface flows in the direction of the widening groove width (i.e., towards the side tending towards the inside of the body 20a). As a result, the amount of oil flowing into the body 20a increases compared to a groove with a constant groove width (i.e., not conical).

[0113] Furthermore, in this embodiment, the guide groove 20bg is formed as a straight groove. However, it can also be formed as a groove inclined relative to the generatrix direction of the bearing protrusion 20b, or it can be formed as a spiral groove. In particular, when the guide groove 20bg is formed as a spiral groove, the spiral groove-shaped guide groove 20bg functions as a screw pump along with the aforementioned relative rotation, thereby further enhancing the function of supplying oil into the body 20a.

[0114] On the other hand, the center of the second housing 20B has a through hole, which forms an oil drain outlet 20o that drains oil from the body 20a into the transmission 10. Furthermore, the second housing 20B forms another side wall of the differential housing 20, and the inner surface of the second housing 20B is formed as an annular plane orthogonal to the first axis X1, forming a second half-shaft gear support surface 20sf2. Moreover, the rear-side protrusion of the half-shaft gear 24, supported on the rear side by the second half-shaft gear support surface 20sf2, fits into the oil drain outlet 20o.

[0115] Furthermore, the oil drain outlet 20o is configured such that its axial position overlaps with the axial position of at least a portion of the oil reservoir O at the bottom of the transmission 10. This shortens the path for oil discharged from the differential 20 through the oil drain outlet 20o back to the oil reservoir O, allowing oil to quickly return from the differential 20 to the oil reservoir O. Therefore, it is advantageous to set the oil level f in the oil reservoir O at a lower level.

[0116] Furthermore, the oil outlet 20o is configured such that its axial position overlaps with the axial position of at least a portion (the middle portion) of the planetary gear P of the reducer R described later. Thus, when a portion of the oil discharged from the differential housing 20 and through the oil outlet 20o is dispersed radially outward by the centrifugal force generated by the rotation of the planet carrier C of the reducer R, the oil can be effectively used to lubricate the planetary gear P.

[0117] In the differential housing 20 of this embodiment, the oil inlet 20i and the oil outlet 20o are cylindrical surfaces centered on the rotation axis of the differential housing 20 (i.e., the first axis X1), and the diameter of the oil outlet 20o is larger than the diameter of the oil inlet 20i. Therefore, the radial distance from the first axis X1 to the inner circumferential surface of the oil outlet 20o (or to the bottom of the oil groove if one exists there) is greater than the radial distance from the first axis X1 to the inner circumferential surface of the oil inlet 20i (or to the bottom of the oil groove if one exists there).

[0118] Therefore, when oil accumulates within the body 20a and the oil level rises, the oil level reaches the lowest part of the inner circumferential surface of the oil outlet 20o before the inner circumferential surface of the oil inlet 20i. Thus, oil is preferentially discharged from the oil outlet 20o compared to the oil inlet 20i. This ensures the smooth flow of oil from the oil inlet 20i into the body 20a and through the body 20a to the oil outlet 20o.

[0119] Next, an example of the differential gear mechanism 21 will be described. The differential gear mechanism 21 includes a pinion shaft 22, a pair of pinions 23, and a pair of half-shaft gears 24. The two ends of the pinion shaft 22 are fitted and fixed to the first housing 20A (particularly the body 20a) of the differential housing 20 and are arranged on a second axis X2 orthogonal to the first axis X1. The pair of pinions 23 are supported on the pinion shaft 22 in a rotatable manner. The pair of half-shaft gears 24 mesh with each pinion 23 and are rotatable about the first axis X1. A support hole is formed in the body 20a, and the two ends of the pinion shaft 22 are fitted and supported in the support hole. The peripheral wall portion of the support hole in the body 20a forms a pinion shaft support portion 20k.

[0120] One end of the pinion shaft 22 is pressed into a locking pin 28 (see reference) that extends through the end and is fixed to the body 20a. Figure 9 It is fixed to the torso 20a. In addition, the means of fixing the pinion shaft 22 is not limited to the means described in the embodiment, and other means of fixing may be used (e.g., riveting, threading, retaining ring, etc.).

[0121] The pinion 23 and the half-shaft gear 24 are formed from bevel gears; however, the type of gear is not limited to bevel gears. A pair of half-shaft gears 24 function as output gears of the differential gear mechanism 21, with the inner ends of the first output shaft 51 and the second output shaft 52 respectively engaging with the splines on the inner circumferential surfaces of the two half-shaft gears 24. Furthermore, in Figure 1 and Figure 2 In order to clearly show the structure of the guide groove on the inner circumferential surface of the bearing protrusion 20b, a part of the second output shaft 52 is indicated by a double-dotted line.

[0122] The spherical back surfaces of each pinion 23 are supported by the pinion support surface 20pf of the body 20a via shims and in a manner that allows rotation and sliding about the second axis X2. Furthermore, the flat back surfaces of each axle gear 24 are supported by the first axle gear support surface 20sf1 and the second axle gear support surface 20sf2 via shims and in a manner that allows rotation and sliding about the first axis X1. Alternatively, the shims may be omitted if necessary.

[0123] Furthermore, the rotational driving force transmitted from the planetary carrier C of the reducer R to the first housing 20A (and further to the differential housing 20) is distributed by the differential gear mechanism 21 to the first output shaft 51 and the second output shaft 52 in a manner that allows the first output shaft 51 and the second output shaft 52 to rotate at different speeds. Moreover, the differential function of the differential gear mechanism 21 is a well-known function, and therefore its description is omitted.

[0124] However, an oil groove 26 is provided on the inner surface of the second housing 20B. The oil groove 26 extends radially outward from the oil outlet 20o and opens into the body 20a of the differential housing 20 at the outer side of the outer periphery of the corresponding half-shaft gear 24. Figure 2 , Figure 6 , Figure 7 As shown, a pair of oil grooves 26 are formed at the position corresponding to each pinion 23.

[0125] That is, the oil sump 26 is positioned such that the first opening end 26i can directly receive the oil that has been scattered by the pinion 23 due to its rotation, wherein the first opening end 26i forms the inlet for oil to enter the oil sump 26. More specifically, on the projection plane orthogonal to the rotation axis of the transmission unit U, i.e., the first axis X1 (refer to...) Figure 6 During observation, the first opening end 26i of the oil groove 26 that opens into the body 20a is positioned as follows: on the inner side of the outermost radial position of the pinion 23 (i.e., the position that overlaps with the pinion 23) and does not overlap with the pinion shaft 22.

[0126] Furthermore, the first opening end 26i of each oil sump 26 faces the internal space of the differential gearbox 20 (body 20a) at a position corresponding to the outer periphery of the half-shaft gear 24, and the second opening end 26o, which serves as the oil outlet, faces the oil discharge outlet 20o, as shown below. Figure 6 As shown, the entire area of ​​the oil sump 26, or the predetermined area that is continuous from the first opening end 26i, tilts radially inward (i.e., tilts away from the back of the corresponding half-shaft gear 24) and extends as it moves from the first opening end 26i toward the second opening end 26o.

[0127] According to this tilt, when the oil splashed from the rotating pinion 23 flows into the oil trough 26 from the first opening end 26i, it tends to flow towards the second opening end 26o due to the centrifugal force generated by the rotation of the differential gear 20 within the oil trough 26. Therefore, the oil trough 26 can effectively utilize the flow momentum of the oil splashed from the pinion 23 to efficiently guide the oil to the second opening end 26o side. In this case, the oil flowing in the oil trough 26 comes into contact with the back side of the rotating half-shaft gear 24, which may slightly weaken the flow momentum of the oil heading towards the second opening end 26o side. However, by tilting as described above, the oil trough 26 can be moved as far away from the back side of the half-shaft gear 24 as possible. Therefore, the oil flowing in the oil trough 26 is less likely to come into contact with the half-shaft gear 24, thereby avoiding the aforementioned undesirable situation or minimizing its occurrence.

[0128] In addition, such as Figure 6 As shown, when viewed from a projection plane orthogonal to the first axis X1, the pair of oil grooves 26 corresponding to each pinion 23 are formed in the following shape: the grooves are inclined to one and the other circumferentially relative to a virtual straight line extending radially outward from the oil outlet 20o (the second opening end 26o) between the two oil grooves 26. Due to this inclination, when the differential 20 rotates in either forward or reverse direction, one of the oil grooves 26 can agitate the oil accumulated in the differential 20 and guide it to the oil outlet 20o side, thereby enabling efficient discharge of oil into the transmission 10.

[0129] Next, refer to Figures 3-6 An example of a speed reducer R is described. The speed reducer R includes a sun gear 31, a ring gear 32, a plurality of planetary gears P (three in the example shown in the figure), and a planet carrier C. The sun gear 31 forms the input side of the speed reducer R. The ring gear 32 is arranged concentrically with respect to the sun gear 31 at an axially offset position. The plurality of planetary gears P mesh with the sun gear 31 and the ring gear 32. The planet carrier C supports the plurality of planetary gears P via a pivot 33 so that they can rotate freely.

[0130] Each planetary gear P is a second-stage planetary gear that integrally has a major diameter gear portion P1 and a minor diameter gear portion P2, and in this embodiment, it is coaxial with the pivot 33 and formed as a single unit. The major diameter gear portion P1 meshes with the sun gear 31, and the minor diameter gear portion P2 is formed with a smaller diameter than the major diameter gear portion P1 and meshes with the ring gear 32 on one side of the axial direction (i.e., the side closer to the first unit support bearing Bc1).

[0131] Furthermore, in the embodiment, the large diameter gear P1, the small diameter gear P2, the sun gear 31, and the ring gear 32 have gear teeth (e.g., helical teeth) that bear thrust due to meshing reaction force; however, they may also be gear teeth other than helical teeth.

[0132] The sun gear 31 is constructed such that a gear portion 31g is formed on the outer periphery of the front part of the cylindrical sun gear body 31m. The outer periphery of the middle part of the sun gear body 31m is supported on the gearbox 10 (the protrusion 12b of the cover 12) in a rotatable manner via multiple bearings Bs. An oil seal 15 is installed between the adjacent bearings Bs, between the outer peripheral surface of the sun gear 31 and the inner peripheral surface of the protrusion 12b. Furthermore, the first output shaft 51 loosely passes through the interior of the sun gear 31 longitudinally. In addition, an axial clearance is formed between the front end face of the sun gear 31 and the opposing surface of the outer side of the second housing 20B of the differential 20, which is always in communication with the interior space of the gearbox 10.

[0133] The outer end of the sun gear body 31m (not shown) is linked to the output side of a power source (e.g., an electric motor) (not shown) via a linkage mechanism (not shown), thereby enabling rotational power to be input from the power source. Furthermore, the inner circumference of the sun gear body 31m and the outer circumference of the first output shaft 51 are sealed by a sealing device (not shown) disposed on the outside of the gearbox 10.

[0134] The outer peripheral surface of the ring gear 32 is fitted and fixed (e.g., by a known anti-disengagement device including a retaining ring 71 and a retaining ring 72) to the inner peripheral surface of the axial middle portion of the body 11a of the housing body 11. On the outer peripheral surface of the ring gear 32, a plurality of anti-rotation protrusions 32t are integrally formed at circumferential intervals. These anti-rotation protrusions 32t engage with a plurality of anti-rotation grooves 11at in a manner that prevents relative rotation. The plurality of anti-rotation grooves 11at are formed on a circumferential local area of ​​the inner peripheral surface of the body 11a, corresponding to the ring gear 32.

[0135] The planetary carrier C comprises a planetary carrier base portion Cm, three large-diameter gear support portions Cp, and three planetary carrier arm portions Ca. The outer periphery of the planetary carrier base portion Cm is rotatably supported on the second end wall portion 12s of the gearbox 10 via the aforementioned second unit support bearing Bc2. The planetary carrier base portion Cm is formed as a cylinder surrounding the gear portion 31g of the sun gear 31. The three large-diameter gear support portions Cp are integrally connected to the planetary carrier base portion Cm, and each of the three planetary gears P has one end of its pivot 33 (particularly the outer end near the large-diameter gear portion P1) supported by the first planetary gear bearing Bp1, allowing for free rotation. The three planetary carrier arm portions Ca are located between circumferentially adjacent large-diameter gear support portions Cp. Furthermore, the planetary carrier base portion Cm, the large-diameter gear support portions Cp, and the planetary carrier arm portions Ca are integrated together to form a planetary carrier assembly.

[0136] Furthermore, the three planetary carrier arms Ca and the three connecting arms 20Ac that are integrally protruding from the outer periphery of the first housing 20A of the differential gearbox 20 corresponding to the three planetary carrier arms Ca are joined together in a removable manner by bolts B3 that are spirally inserted from the planetary carrier arms Ca, thereby combining the planetary carrier C and the first housing 20A into one unit.

[0137] Furthermore, on the outer periphery of the first housing 20A, three support arms 20Ap are integrally protruding. These three support arms 20Ap are axially spaced apart from the three large-diameter gear support arms Cp of the planetary carrier C and axially adjacent to the small-diameter gear portion P2 of the planetary gear P. A pivot 33 extending integrally from the small-diameter gear portion P2 is rotatably supported in these support arms 20Ap via the second planetary gear bearing Bp2.

[0138] Thus, one end of the pivot 33 of the planetary gear P on the side of the large diameter gear portion P1 is supported on the planet carrier C via the first planetary gear bearing Bp1, and the other end of the pivot 33 of the planetary gear P on the side of the small diameter gear portion P2 is supported on the support arm portion 20Ap of the first housing 20A via the second planetary gear bearing Bp2. The first bearing Bp1 adopts a bearing structure (e.g., a ball bearing) capable of withstanding both radial loads and axial thrust loads, and the second bearing Bp2 adopts a needle roller bearing.

[0139] Furthermore, the sidewall 20as of the differential housing 20 (first housing 20A) on one side in the axial direction integrally has a cylindrical portion 20At, which concentrically surrounds the bearing protrusion 20b, which serves as the second protrusion. The inner circumference of the parking gear 55, as a component, is fitted and fixed to the outer circumference of the cylindrical portion 20At. The parking gear 55 is axially adjacent to the second bearing Bp2, which serves as the planetary gear support. In this embodiment, spline engagement and locking means such as snap rings are used together as fixing means. However, the component is not limited to the parking gear 55, and may be replaced by other functional components that are fitted and fixed to the outer circumference of the cylindrical portion 20At and can perform certain functions within the transmission 10.

[0140] A cavity 56 is formed between the mating surfaces of the inner circumference of the parking gear 55 and the outer circumference of the cylindrical portion 20At, communicating with the second bearing Bp2 for the planetary gear. The cavity 56 is formed in an annular shape, or the cavity 56 is formed in a localized area in the circumferential direction. Furthermore, a connecting hole 57 is formed in the cylindrical portion 20At to connect the cavity 56 and the inner circumferential surface of the cylindrical portion 20At.

[0141] As described above, the large-diameter gear portion P1 of the planetary gear P is axially supported on the planet carrier C, and the small-diameter gear portion P2 of the planetary gear P is axially supported on the differential housing 20. Furthermore, the second housing 20B of the differential housing 20 is clamped between the first housing 20A and the planet carrier C, which is attached to the first housing 20A, thereby fixing the second housing 20B to the first housing 20A. In this case, at least one (in this embodiment, both) of the opposing surfaces of the planet carrier C (planet carrier arm Ca) and the body 20a of the first housing 20A has axially recessed recesses Cao and 20ao, and the second housing 20B is clamped between the planet carrier C and the first housing 20A in a state where it is fitted into the aforementioned recesses Cao and 20ao.

[0142] Furthermore, as shown in the embodiment, the aforementioned opposing surfaces not only include opposing surfaces that directly abut each other, i.e., the so-called mating surfaces, but also opposing surfaces that are separated from each other by a gap. In addition, the latter opposing surfaces (i.e., opposing surfaces that are not mating surfaces) may be provided with recesses that are recessed in the axial direction, similar to the aforementioned recesses Cao and 20ao, and the second housing 20B may be fitted into the recesses.

[0143] In addition, such as Figure 1 and Figure 9As shown, the differential 20, especially the first housing 20A, also includes at least a portion of a contamination containment section 70 capable of capturing contaminants from the oil within the body 20a. Here, contaminants are short for contaminants, referring to a general term for fine foreign matter, such as metal powder, that is generated from the movable parts within the gearbox 10 due to mechanical contact between metal parts and mixes into the oil.

[0144] The aforementioned waste collection section 70 has an inlet 70i facing the inside of the torso 20a. Furthermore, the inlet 70i is located in the maximum inner diameter section 20d on the inner surface of the differential housing 20, where centrifugal force is strongest, thereby facilitating the introduction of waste in the oil within the torso 20a into the waste collection section 70 by means of centrifugal force.

[0145] In addition, such as Figure 1 and Figure 9 As shown, in this embodiment, the waste collection section 70 is positioned at a location offset by 90 degrees from the axis of the pinion shaft 22. Therefore, the waste collection section 70 is positioned circumferentially away from the pinion support surface 20pf, through which the pinion shaft 22 passes.

[0146] In addition, at least a portion of the inlet 70i of the waste collection section 70 can be positioned on the side of the oil outlet 20o, which is closer to the maximum inner diameter portion 20d on the inner surface of the differential box 20.

[0147] Furthermore, a folding portion 70k is provided around the inlet 70i of the waste collection section 70 to partially block the inlet 70i. In this embodiment, the folding portion 70k is formed on the outer peripheral wall of the second housing 20B facing the inlet 70i. Alternatively, the folding portion 70k may also be formed on the first housing 20A or the planetary carrier C.

[0148] Furthermore, each waste containment section 70 is formed across the planetary carrier arm Ca and the first housing 20A. In other words, the waste containment section 70 is defined between each other by a containment section Cac on the planetary carrier C side recessed at the joint surface of the planetary carrier arm Ca with the body 20a, and a containment section 20ac on the body 20a side recessed at the joint surface of the body 20a with the planetary carrier arm Ca. Alternatively, the containment section Cac on the planetary carrier C side may be omitted, and the waste containment section 70 may be formed by the containment section 20ac on the body 20a side and the flat end face of the planetary carrier arm Ca that blocks the containment section 20ac on the body 20a side.

[0149] Furthermore, the planetary gear P of the reducer R, especially the large diameter gear support P1, can agitate the oil in the oil reservoir O at the bottom of the gearbox 10 by revolving in the forward direction of the planet carrier C. An oil guide G is provided inside the gearbox 10 to capture the agitated oil and efficiently supply it to the lubricated parts (e.g., the first unit support bearing Bc1 and the second unit support bearing Bc2) inside the gearbox 10 for lubrication.

[0150] In this case, the forward rotation direction of the planetary carrier C refers to the direction in which the planetary carrier C rotates when the first output shaft 51 and the second output shaft 52, and consequently the left and right wheels, rotate in the direction that propels the vehicle forward via the driving force of the electric motor, which serves as the power source, and through the transmission unit U. For example, taking... Figure 3 In this case, the forward rotation direction of the planetary carrier C is clockwise as shown in the figure. Furthermore, the planetary gear P is configured such that its large diameter gear portion P1 is submerged below the oil storage surface f of the oil reservoir O at the bottom of its revolution trajectory. This configuration enables the large diameter gear portion P1 to agitate the oil.

[0151] The oil guide section G is composed of a first oil guide section G1 and a second oil guide section G2. Specifically, the first oil guide section G1 includes an oil capturing section 40 and a first oil guiding section 41. The oil capturing section 40 is capable of capturing the oil stirred up by the large-diameter gear section P1 during its revolution; the first oil guiding section 41 extends axially from the oil capturing section 40 and guides a portion of the oil captured by the oil capturing section 40 to the oil inlet 20i or the periphery of the oil inlet 20i. The oil capturing section 40 is positioned radially outward on the revolution trajectory of the large-diameter gear section P1 within the gearbox 10.

[0152] In this embodiment, a first oil guide portion G1 is formed by a guide groove-shaped member 4 with an open upper surface (i.e., a U-shaped cross-section). The guide groove-shaped member 4 is disposed along and fixed to the inner surface of the gearbox body 11 of the gearbox 10. The guide groove-shaped member 4 is arranged to pass longitudinally through a mounting groove 11g, which is a continuous groove recessed on the inner surface of the gearbox body 11 (more specifically, in the torso 11a and the first end wall portion 11s). Furthermore, the guide groove-shaped member 4 is fixed to the gearbox body 11 by fixing the lower part of the guide groove-shaped member 4 to the torso 11a via a plurality of mounting pieces 47 (e.g., screw fixing, riveting, welding, etc.).

[0153] In addition, the mounting piece 47 can be fixed to a part of the guide groove member 4 other than the lower part (e.g., the side wall part), or it can be formed as an integral part with the guide groove member 4.

[0154] The upstream portion of the guide groove-shaped component 4, which functions as the oil capturing section 40, extends horizontally and linearly along the first axis X1. On the other hand, the longer downstream portion of the guide groove-shaped component 4, which functions as the first oil guiding section 41, includes a first guide groove portion 411 along the inner circumferential surface of the body 11a of the housing body 11, and a second guide groove portion 412 that bends from the first guide groove portion 411 and along the inner side surface of the first end wall portion 11s.

[0155] Furthermore, the guide groove member 4 is designed with a gentle, continuous downward slope from the upstream end of the first guide groove portion 411 (i.e., the downstream end of the oil capturing portion 40) towards the downstream end of the second guide groove portion 412. Therefore, the oil captured by the oil capturing portion 40 can flow smoothly along the oil capturing portion 40 and the first oil guide portion 41, and can be supplied to the side of the first unit support bearing Bc1 facing the downstream end of the oil capturing portion 40. Additionally, as... Figure 2 As shown, the middle portion (first guide groove portion 411) of the first oil guide portion 41 is configured to pass radially between the ring gear 32 and the body 11a.

[0156] Furthermore, the second oil guide section G2 has the second oil guide section 42 as its main body and is provided along the inner side 12si of the second end wall section 12s opposite to the reducer R of the gearbox 10. The second oil guide section 42 receives a portion of the oil captured by the oil capture section 40 from the end of the oil capture section 40 located on the other side of the axial direction and guides it to the second unit support bearing Bc2. That is, the inner surface 12si is formed approximately along a virtual plane that is orthogonal to the first axis X1 and passes through the oil reservoir O. A stepped portion 17 is formed on the inner surface 12si in a straight line extending from the position directly below the oil capture portion 40 toward the second unit support bearing Bc2 and in a downward slope, so that the upper surface side is open. In addition, around the through hole 12sh, an annular protrusion 12sib is provided on the inner surface 12si toward the axial inner side. On the protrusion 12sib, a slit-shaped communicating oil groove 29 that connects the radial inner side and the outer side of the protrusion 12sib is formed at a position corresponding to the inner end of the stepped portion 17 in the longitudinal direction.

[0157] Furthermore, a second oil guide section 42 with an open upper surface and a guide groove shape is formed by the inner surface of the stepped portion 17 and the strip-shaped plate 18 that extends linearly along the stepped portion 17 and is screwed to the second end wall portion 12s on the lower side of the stepped portion 17. Therefore, the oil received from the end of the oil capturing portion 40 on the other side of the axial direction by the second oil guide section 42 flows along the second oil guide section 42 and is supplied to the second unit support bearing Bc2 and its surrounding portion through the communicating oil groove 29. Alternatively, the second oil guide section 42 can also be formed by a guide groove-shaped member that is an integral part, such as the guide groove-shaped member 4 that forms the first oil guide section G1.

[0158] Furthermore, when the planetary gear P (large diameter gear P1) revolves in conjunction with the rotation of the planet carrier C as described above, it will move in the opposite direction to the direction of revolution. Figure 3 The oil rotates counterclockwise (in the same direction as the revolution), which may cause the oil to disperse in the opposite direction to the revolution (i.e., the direction that stirs the oil), thereby reducing the effect of stirring the oil. In this embodiment, as... Figure 3 As shown, the oil capturing section 40 of the first oil guide section G1 is positioned on the front side of the outer peripheral wall of the gearbox 10, starting from the lowest part of the oil reservoir O and in the forward rotation direction of the planetary carrier C. Figure 3 On the left half of the circumference.

[0159] Therefore, even if the planetary gear P rotates in the opposite direction to its revolution, the oil capturing section 40, which has an open upper surface, can effectively capture oil that is scattered in the opposite direction to the direction in which the oil is stirred up by the revolution. Furthermore, to fully achieve this oil capturing effect, the circumferential position of the oil capturing section 40 can be set at the aforementioned outer peripheral wall half-circumference of the gearbox 10 (i.e., Figure 3 Any position in the left half of the perimeter, not limited to only being set in Figure 3 The circumferential position of the embodiment shown.

[0160] In addition, such as Figure 3 As shown, a guide recess 11ao is formed on the inner surface of the outer peripheral wall of the housing body 11. The guide recess 11ao is disposed adjacent to the front side of the oil capturing part 40 in the aforementioned forward rotation direction and is recessed towards the radially outer side of the housing body 11. The guide recess 11ao is formed as a circumferentially extending groove, and the bottom of the groove gradually deepens in the circumferential direction as it approaches the oil capturing part 40. The axial position of the guide recess 11ao is the same as the axial position of at least a portion of the oil capturing part 40, so that when the large diameter gear part P1 faces and passes through the guide recess 11ao, a portion of the scattered oil can be effectively captured and allowed to flow along the guide recess 11ao, thereby efficiently guiding it to the oil capturing part 40.

[0161] Next, the function of the above-described implementation method will be explained.

[0162] In transmission device A, if the sun gear 31 is driven to rotate by a power source (e.g., an electric motor) not shown, the sun gear 31 and the ring gear 32 mesh with the large diameter gear portion P1 and the small diameter gear portion P2 of the second-stage planetary gear P, respectively, thereby reducing the rotational driving force of the sun gear 31 in two stages and transmitting it to the planet carrier C. Then, the rotational driving force transmitted to the differential housing 20 (especially the first housing 20A) fixed to the planet carrier C is distributed by the differential gear mechanism 21 within the differential housing 20 in a manner that allows the first output shaft 51 and the second output shaft 52 to rotate at different speeds, and further transmitted from the first output shaft 51 and the second output shaft 52 to the left and right drive wheels.

[0163] Furthermore, in the transmission device A, the transmission unit U, in which the differential device D is arranged on one side of the axial direction and the planetary gear reducer R is arranged on the other side of the axial direction, is housed in the gearbox 10, which has an oil reservoir O at the bottom; the differential housing 20 of the differential device D has a body 20a capable of storing oil, an oil inlet 20i opening to one side of the axial direction, and an oil outlet 20o opening to the other side of the axial direction; the large diameter gear P1 of the planetary gear P, which revolves in the same direction as the planet carrier C, is arranged such that the lower part of the large diameter gear P1 on the revolution trajectory is submerged below the oil storage surface f of the oil reservoir O; the first oil guide G1, which captures the oil stirred up from the oil reservoir O by the large diameter gear P1 through the above revolution and guides it to the oil inlet 20i, is provided on the gearbox 10 in such a way that it extends from the radially outer position on the revolution trajectory toward one side of the axial direction.

[0164] Therefore, the large-diameter gear P1, which revolves in conjunction with the rotation of the planetary carrier C, can not only fully agitate the oil stored in the oil reservoir O, but the agitated oil can also be captured by the oil capturing part 40 of the first oil guide part G1. The captured oil can then be guided to the oil inlet 20i via the first oil guide part 41 and the oil inlet space 16, thereby ensuring sufficient oil supply to the body 20a from the oil inlet 20i. Then, the oil accumulated in the body 20a flows back to the oil reservoir O in the gearbox 10 through the oil outlet 20o. Therefore, even if the oil level f in the oil reservoir O is low enough to partially submerge the large-diameter gear P1 when the transmission A is stationary, the oil agitated by the large-diameter gear P1 can be efficiently and fully supplied to the differential gearbox 20 via the first oil guide part G1. Furthermore, it can ensure the performance of lubrication of the differential gear mechanism 41 in the differential box 20, and can also set the oil level f of the oil reservoir O to a low level to suppress the oil stirring resistance, thereby improving the transmission efficiency.

[0165] Furthermore, an oil pump is not required to supply oil to the differential 20, thereby achieving cost savings.

[0166] Furthermore, the first unit support bearing Bc1 on one side of the axial direction of the support transmission unit U is sandwiched between the inner peripheral surface of the protrusion 11b and the outer peripheral surface of the bearing protrusion 20b. The protrusion 11b, as the first protrusion, protrudes from the inner surface of the first end wall portion 11s in the gearbox 10, which is located on the same side as the first unit support bearing Bc1. The bearing protrusion 20b, as the second protrusion, protrudes from the side wall 20as in the differential box 20, which is located on the same side as the first unit support bearing Bc1. The oil inlet space 16 is defined by the oil seal 14 that seals between the outer periphery of the second output shaft 52 and the through hole 11sh of the first end wall portion 11s, the inner peripheral surface of the protrusion 11b, and the outer surface of the first unit support bearing Bc1. The oil inlet 20i faces the oil inlet space 16. The protrusion 11b has a through hole 11bh that connects its interior and exterior, and the downstream end of the first oil guide G1 (the second guide groove portion 412 of the first oil guide 41) through the through hole 11bh opens toward the oil inlet space 16. A first oil supply mechanism OS1 and a second oil supply mechanism OS2 are provided between the bearing protrusion 20b and the second output shaft 52. The first oil supply mechanism OS1 and the second oil supply mechanism OS2 supply oil in the oil inlet space 16 to the body 20a through the oil inlet port 20i in response to the relative rotation between the bearing protrusion 20b and the second output shaft 52.

[0167] Therefore, by utilizing the aforementioned relatively rotating oil supply mechanisms OS1 and OS2, oil flowing out of the first oil guide section G1 and guided to the oil inlet space 16 can be efficiently supplied from the oil inlet 20i to the rotating differential housing 20. Furthermore, the oil accumulated in the oil inlet space 16 can be used to efficiently lubricate the first unit support bearing Bc1.

[0168] Furthermore, the sidewall 20as of the differential gearbox 20 integrally has a cylindrical portion 20At surrounding the bearing protrusion 20b. The inner circumference of the parking gear 55, which is axially adjacent to the second bearing Bp2 for the planetary gear, is fitted and fixed to the outer circumference of the cylindrical portion 20At. A cavity portion 56 communicating with the second bearing Bp2 for the planetary gear is formed between the mating surfaces of the inner circumference of the parking gear 55 and the outer circumference of the cylindrical portion 20At. A connecting hole 57 is formed in the cylindrical portion 20At to communicate with the inner circumferential surface of the cylindrical portion 20At. Thus, the oil that reaches the first unit support bearing Bc1 via the first oil guide section G1 and the oil inlet space 16 lubricates the first unit support bearing Bc1, flows along the side wall 20as of the differential box 20, and reaches the inner circumferential surface of the cylindrical section 20At by means of centrifugal force. The oil flows to the cavity section 56 through the connecting hole 57, and from the cavity section 56 to the second bearing Bp2 for the planetary gear, thereby efficiently lubricating the second bearing Bp2 for the planetary gear.

[0169] Furthermore, the second unit support bearing Bc2 on the other side of the axial direction in the support transmission unit U is mounted on the second end wall portion 12s of the gearbox 10 facing the reducer R, and the inner surface 12si of the second end wall portion 12s is formed approximately along a virtual plane orthogonal to the first axis X1 and passing through the oil reservoir O. The second oil guide portion G2, which receives a portion of the oil captured by the oil capture portion 40 and guides it to the second unit support bearing Bc2, is provided along the inner surface 12si of the second end wall portion 12s.

[0170] Therefore, the second oil guide section G2 can receive a portion of the oil captured by the oil capture section 40 of the first oil guide section G1, and can guide the oil to the second unit support bearing Bc2 and its periphery provided in the end wall section 12s of the gearbox 10, thereby efficiently lubricating the second unit support bearing Bc2. Moreover, the inner surface 12si of the second end wall section 12s where the second oil guide section G2 is provided is arranged approximately along a virtual plane orthogonal to the first axis X1 and passing through the oil reservoir O. Therefore, the oil lubricating the second unit support bearing Bc2 flows approximately vertically downward along the inner surface 12si, and can quickly reach the oil reservoir O with the shortest path. Therefore, it is advantageous to set the oil level f of the oil reservoir O at a low level.

[0171] Furthermore, an oil groove 26 is provided on the inner surface of the differential housing 20 (more specifically, the inner surface of the second housing 20B) facing the back of the half-shaft gear 24 located on the other side of the axial direction. The oil groove 26 extends radially outward from the oil outlet 20o and opens into the differential housing 20 at the outer side of the outer periphery of the corresponding half-shaft gear 24. The first opening end 26i of the oil groove 26 opening into the differential housing 20 is positioned such that oil that is scattered from the pinion 23 due to the rotation of the pinion 23 can be introduced.

[0172] Therefore, the oil sump 26 can efficiently deliver oil to the second opening end 26o facing the oil drain outlet 20o by utilizing the flow energy of the oil scattered by the pinion 23 within the differential gear 20. Moreover, since the first opening end 26i of the oil sump 26 can be confined to a specific range corresponding to the oil scattering area of ​​the pinion 23, the length of the oil sump 26 can be shortened as much as possible, thereby enabling the oil scattered by the pinion 23 to quickly flow back to the oil drain outlet 20o and return from the oil drain outlet 20o to the oil storage section O.

[0173] Furthermore, as described above, the planetary gear P (especially the large diameter gear P1) revolves in the forward direction of the planet carrier C, thereby stirring up the oil in the oil reservoir O. On the other hand, the rotation that occurs in the opposite direction along with the revolution causes the oil to scatter in the opposite direction to the direction of revolution (i.e., the direction that stirs up the oil).

[0174] In this embodiment, the oil capturing section 40 of the first oil guide section G1 is positioned on the outer peripheral wall half of the gearbox 10, starting from the lowest part of the oil reservoir O and located on the front side in the forward rotation direction of the planetary carrier C. Figure 3 On the left half of the outer circumference, the oil capturing section 40 can effectively capture oil that is scattered in the opposite direction. That is, even if the planetary gear P rotates in the direction opposite to its revolution direction, the oil capturing section 40 located on the outer half of the outer circumference can fully capture oil that is scattered in the direction opposite to its revolution direction, thereby minimizing the impact of the rotation on the capturing effect.

[0175] Furthermore, particularly in the transmission unit U of the embodiment, the differential housing 20 is configured to be divided into a first housing 20A and a second housing 20B. On the other hand, the large diameter gear portion P1 of the planetary gear P is shaft-supported on the planet carrier C, and the small diameter gear portion P2 of the planetary gear P is shaft-supported on the first housing 20A. The second housing 20B is clamped between the first housing 20A and the planet carrier C attached to the first housing 20A. Through this clamping, the second housing 20B is fixed to the first housing 20A. Thus, the large planet carrier C, which shaft-supports the large diameter gear portion P1 of the planetary gear P, can be subsequently attached to the first housing 20A as a different component from the differential housing 20. Therefore, compared with the conventional structure that integrates the large planet carrier C and the differential housing 20, not only is the structure of the differential housing 20 simplified, but the reducer R also has excellent assembly performance, thereby achieving cost savings.

[0176] Moreover, the second housing 20B can be fixed simply by clamping the second housing 20B between the planetary carrier C and the first housing 20A. Therefore, there is no need for a special fixing means to fix the second housing 20B. That is, the second housing 20B can be combined with the first housing 20A by using the simple structure of the planetary carrier C.

[0177] Furthermore, in the first housing 20A, a pinion shaft support 20k is provided, corresponding to the pinion shaft 22 that supports the pinion 23 of the differential gear mechanism 21, and the small diameter gear portion P2 of the planetary gear P is shaft-supported in the first housing 20A. Therefore, the rotational force from the planetary gear P or the pinion shaft 22 is not directly input to the second housing 20B, thereby reducing the load on the second housing 20B. Consequently, the rigidity of the second housing 20B can be set to a lower value, thus achieving a lightweight and miniaturized design.

[0178] Furthermore, in this embodiment, at least one (in this embodiment, both) of the opposing surfaces of the planetary carrier C and the first housing 20A has axially recessed recesses Cao and 20ao. The second housing 20B is held between the planetary carrier C and the first housing 20A in a state of fitting into the recesses Cao and 20ao. Thus, by simply fitting the second housing 20B into the recesses Cao and 20ao facing the opposing surfaces, radial positioning of the second housing 20B can be easily and reliably implemented, thereby improving assembly workability.

[0179] Furthermore, in the differential housing 20 of the embodiment, the open end of the first housing 20A on the other side of the axial direction is closed by the second housing 20B. Therefore, the differential gear mechanism 21 can be assembled into the first housing 20A from the other side of the axial direction while the first housing 20A and the second housing 20B are separated. In addition, the first housing 20A and the planet carrier C clamp the planet gear P axially at both ends of the planet gear P. Therefore, the planet gear P can be assembled into the first housing 20A from the other side of the axial direction. Furthermore, the planet gear P can be assembled relative to the first housing 20A, which already has the planet gear P and the second housing 20B assembled, and the planet carrier C can be assembled from the other side of the axial direction in conjunction with the planet gear P. Thus, the differential gear mechanism 21, the second housing 20B, the planet gear P, and the planet carrier C can be assembled sequentially from the same direction (i.e., from the other side of the axial direction) relative to the first housing 20A, resulting in excellent overall assembly performance.

[0180] Furthermore, if the residual contaminants in the oil accumulated in the body 20a of the differential housing 20 cannot be discharged outside the differential housing 20 and continue to increase, the contaminants may spread inside the differential housing 20 during transmission, thereby causing a decrease in the performance of the differential device D. However, the differential housing 20 of this embodiment includes at least a portion of a contaminant receiving portion 70, which has an inlet 70i facing the body 20a of the differential housing 20 and is capable of capturing contaminants from the oil in the body 20a. Moreover, the inlet 70i is disposed at the maximum inner diameter portion 20d in the inner surface of the differential housing 20 where the centrifugal force is strongest, or disposed at a position closer to the oil outlet 20o than the maximum inner diameter portion 20d.

[0181] Therefore, especially in the structure where the inlet 70i is located in the maximum inner diameter portion 20d, when the differential housing 20 rotates, the contaminants in the oil within the body 20a can be effectively captured into the contaminant collection portion 70 by means of centrifugal force, thus suppressing the diffusion of contaminants within the body 20a. Furthermore, the contaminants that have gathered in the maximum inner diameter portion 20d by means of centrifugal force are easily discharged to the oil outlet 20o side along with the oil flowing from the oil inlet 20i toward the oil outlet 20o. Therefore, by positioning the inlet 70i closer to the oil outlet 20o side than the maximum inner diameter portion 20d, contaminants can also be effectively captured into the contaminant collection portion 70. Regardless of the configuration, the performance degradation of the differential device D caused by the diffusion of contaminants can be effectively suppressed.

[0182] Furthermore, a folding portion 70k is provided around the inlet 70i of the aforementioned waste collection section 70 to partially block the inlet 70i. Therefore, even if the inlet 70i temporarily faces downwards as the differential box 20 rotates, waste attempting to flow out of the inlet 70i will be blocked by the folding portion 70k, effectively preventing the waste captured in the waste collection section 70 from escaping from the waste collection section 70.

[0183] Furthermore, if a magnet is provided inside the waste containment section 70 and the waste is attracted to the magnet, it is also possible to prevent the waste that has been captured in the waste containment section 70 from escaping from the waste containment section 70.

[0184] Furthermore, in the transmission unit U of the embodiment, the waste collection section 70 is formed across the planetary carrier C and the differential gearbox 20. Therefore, a portion of the waste collection section 70 is formed not only in the differential gearbox 20 but also in the planetary carrier C. Thus, the capacity of the waste collection section 70 can be easily increased by utilizing the planetary carrier C of the reducer R.

[0185] Furthermore, at least the differential housing 20 (in this embodiment, the planetary carrier C is also included) of the planetary carrier C and the differential housing 20 is recessed axially from the mating surface where the planetary carrier C and the differential housing 20 engage, thereby defining a waste collection portion 70 between the planetary carrier C and the differential housing 20. Therefore, when processing or forming the waste collection portion 70, with the planetary carrier C separated from the differential housing 20 so that the aforementioned mating surface is wide open to the outside, the processing or forming of the waste collection portion 70 can be easily performed from this mating surface. Therefore, even if the bottom width of the waste collection portion 70 is large and the width of the inlet 70i is small, the processing or forming can be performed quickly and accurately.

[0186] Furthermore, the differential box 20 is formed by the divided first box 20A and second box 20B. At least a portion of the waste-receiving section 70 is formed in the first box 20A, and a folding section 70k is formed in the second box 20B. Therefore, the folding section 70k, which narrows the inlet 70i of the waste-receiving section 70, can be easily formed in the second box 20B when it is separated from the first box 20A. Thus, compared to a structure where the folding section 70k is formed in addition to the waste-receiving section 70 in the first box 20A, the processing or forming of the folding section 70k can be performed much more easily.

[0187] Furthermore, in the differential box 20, such as Figure 1 , Figure 9 As shown, the pinion support surface 20pf and the waste collection portion 70 are positioned circumferentially separated from each other in the differential housing 20. Therefore, there is no need to worry about reducing the thickness of the pinion support surface 20pf supporting the back of the pinion 23 in order to form the waste collection portion 70. Thus, even with the waste collection portion 70 provided in the differential housing 20, sufficient support rigidity for the back of the pinion 23 can be ensured.

[0188] also, Figure 10 as well as Figure 11 The second embodiment is shown.

[0189] Implementation Method 2

[0190] The outer surface of the second housing 20B in the first embodiment is flat and has no protrusions, while the second housing 20B′ in the second embodiment has an integrally formed step-shaped protrusion 81 that protrudes outward along the axial direction on its outer surface, which is different from the first embodiment.

[0191] That is, the second housing 20B′ of the second embodiment has a second housing body 80 with a structure substantially the same as the second housing 20B of the first embodiment, and a stepped protrusion 81 integrally protruding from the outer side of the second housing body 80. A plurality of oil grooves 26, the same as those in the first embodiment, are recessed on the inner surface of the second housing body 80. The second opening end 26o of the oil groove 26 passes longitudinally through the inner peripheral surface of the stepped protrusion 81 and extends to the front end of the protrusion 81. The middle step of the outer periphery of the stepped protrusion 81 is axially opposed to the front end of the sun gear 31 with a gap. In addition, the front end portion 81a of the stepped protrusion 81, which is closer to the front end than the middle step, is loosely fitted into the annular recess 31o provided at the inner periphery of the front end of the sun gear 31. Furthermore, an annular oil passage 82, which is always in communication with the internal space of the transmission 10, is formed between the front end portion 81a and the annular recess 31o of the sun gear 31. The inner circumferential surface of the front end portion 81a of the stepped protrusion 81 forms the oil outlet 20o of the differential housing 20. The annular gap between the oil outlet 20o and the first output shaft 51 that loosely passes through the oil outlet 20o communicates with the annular oil passage 82. Therefore, oil that travels from the differential housing 20 (body 20a) through the oil groove 26 to the oil outlet 20o flows smoothly into the transmission 10 via the annular oil passage 82.

[0192] Furthermore, in the first housing 20A of the first embodiment, a cylindrical portion 20At for mounting the parking gear 55 (component) protrudes from the side wall 20as of the first housing 20A. However, in the second embodiment, this cylindrical portion 20At for mounting the component is omitted. Moreover, the cylindrical portion 20At for mounting the component can be designed according to the usage of the transmission device A and as needed. For example, the cylindrical portion 20At may be omitted in the first embodiment and the third embodiment below, or it may be provided in the second embodiment.

[0193] The other structures in the second embodiment are basically the same as those in the first embodiment. Therefore, the constituent elements of the second embodiment are labeled with the same reference numerals as the corresponding constituent elements of the first embodiment, and detailed descriptions are omitted. Furthermore, the second embodiment can also achieve essentially the same effects as the first embodiment.

[0194] In addition, Figures 12-14 The third embodiment is shown in the figure.

[0195] Third implementation method

[0196] The second housing 20B″ of the third embodiment is formed of a flat and thin annular panel 90, and an oil drain outlet 20o is formed by a through hole in the center of the panel 90. In addition, three mounting arms 91 are provided at equal intervals in the circumferential direction on the outer periphery of the panel 90. These three mounting arms 91 correspond to and are adjacent to the three connecting arms 20Ac integrally protruding on the outer periphery of the first housing 20A of the differential housing 20.

[0197] The three mounting arms 91 are clamped between the three connecting arms 20Ac of the first housing 20A and the three planetary carrier arms Ca of the planetary carrier C. However, the opposing surfaces of the connecting arms 20Ac and the planetary carrier arms Ca forming the clamping surface do not have the positioning recesses 20ao and Cao as described in the first and second embodiments, but are simply flat surfaces. Instead, in order to position the second housing 20B in the correct mounting position, positioning pins 92 are inserted into the through holes 91h of each mounting arm 91 and the through holes Cah of the corresponding planetary carrier arms Ca, wherein the positioning pins 92 extend across the through holes 91h and Cah. Furthermore, bolts B3 pass through the planetary carrier arms Ca and the positioning pins 92 and are threaded into the connecting arms 20Ac.

[0198] The other structures in the third embodiment are basically the same as those in the first embodiment. Therefore, the constituent elements of the third embodiment are labeled with the same reference numerals as the corresponding constituent elements in the first embodiment, and detailed descriptions are omitted. Furthermore, the third embodiment can also perform essentially the same functions as the first embodiment.

[0199] The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments, and various design changes can be made without departing from its spirit.

[0200] For example, in the above embodiment, an electric motor is exemplified as the power source that applies rotational driving force to the input part (sun gear 31) of the transmission device A. However, an on-board engine may be used instead of an electric motor as the power source, or both an electric motor and an on-board engine may be used as power sources.

[0201] Furthermore, in the above embodiments, a transmission device A is exemplified in a vehicle (e.g., an automobile) transmission system, and a differential device D in the transmission device A is used to distribute and apply rotational driving force to the left and right drive wheels of the vehicle. However, in the present invention, the differential device D can also be used as a central differential device to distribute and apply rotational driving force to the front and rear drive wheels of the vehicle. Alternatively, the transmission device A of the present invention can also be used as a transmission device composed of a reducer R and a differential device D in various mechanical devices other than vehicles.

[0202] Furthermore, in the above embodiment, an example is shown in which the large diameter gear part P1 and the small diameter gear part P2 of the planetary gear P are integrated. However, the planetary gear assembly and the pivot 33, which integrate the large diameter gear part P1 and the small diameter gear part P2, can also be formed as different components. In this case, the planetary gear assembly is fitted together in a rotatable manner and supported on the pivot 33.

Claims

1. A transmission device, characterized in that, In the transmission device, the transmission unit (U) is housed within a gearbox (10) having an oil reservoir (O) at the bottom. The transmission unit (U) includes a reducer (R) and a differential (D). The differential housing (20) of the differential (D) receives the output of the reducer (R). In the transmission unit (U), the differential (D) is positioned on one axial side, and the reducer (R) is positioned on the other axial side. The reducer (R) includes a sun gear (31), a ring gear (32), multiple planetary gears (P), and a planet carrier (C). The ring gear (32) is concentrically arranged relative to the sun gear (31) and fixed to the gearbox (10); The planetary gear (P) integrally has a large-diameter gear portion (P1) that meshes with the sun gear (31) and a small-diameter gear portion (P2) that meshes with the ring gear (32); The planet carrier (C) supports the plurality of planetary gears (P) so that they can rotate freely, and the planet carrier (C) rotates integrally with the differential box (20). The differential box (20) has a body (20a), an oil inlet (20i), and an oil outlet (20o). The body (20a) can accommodate the differential mechanism (21) and can store oil; The oil inlet (20i) opens on one side of the torso (20a) in the axial direction and communicates with the interior of the torso (20a); The oil outlet (20o) opens on the opposite side of the body (20a) in the axial direction, and allows the stored oil in the body (20a) to be discharged into the gearbox (10). The large-diameter gear (P1), which revolves in the same direction as the planetary carrier (C) when it rotates, is configured such that the lower part of the large-diameter gear (P1) on its revolution trajectory is submerged below the oil storage surface (f) of the oil reservoir (O). The first oil guide (G1) is provided on the gearbox (10) in such a way that it extends from a radially outer position on the revolution trajectory toward one side of the axial direction. The first oil guide (G1) captures the oil stirred up from the oil reservoir (O) by the large diameter gear (P1) through the revolution and guides the captured oil to the oil inlet (20i).

2. The transmission device according to claim 1, characterized in that, The axial position of the oil outlet (20o) overlaps with the axial position of at least a portion of the oil storage section (O).

3. The transmission device according to claim 1 or 2, characterized in that, The axial position of the oil outlet (20o) overlaps with the axial position of at least a portion of the planetary gear (P).

4. The transmission device according to any one of claims 1 to 3, characterized in that, A first unit support bearing (Bc1) is clamped and installed between the inner peripheral surface of the first protrusion (11b) and the outer peripheral surface of the second protrusion (20b). The first unit support bearing (Bc1) is used to support the transmission unit (U) on the gearbox (10), and the first unit support bearing (Bc1) is located on one side of the axial direction. The first protrusion (11b) is formed on the end wall portion (11s) of the gearbox (10) on the side of the axial direction. The second protrusion (20b) protrudes from the outer surface of the side wall (20as) of the differential box (20) on the side of the axial direction. The oil inlet space (16) is defined by the oil seal (14), the inner circumferential surface of the first protrusion (11b), and the outer surface of the first unit support bearing (Bc1). The oil inlet (20i) faces the oil inlet space (16). The oil seal (14) seals the outer circumference of the output shaft (52) and the through hole (11sh) of the end wall portion (11s) through which the output shaft (52) passes. The output shaft (52) is inserted into the second protrusion (20b) and rotates in conjunction with the output side of the differential mechanism (21). The first protrusion (11b) has a through hole (11bh) that connects the oil inlet space (16) and other spaces within the gearbox (10), and the opening position of the downstream end of the first oil guide (G1) is set such that oil guided by the first oil guide (G1) flows into the oil inlet space (16) through the through hole (11bh). An oil supply mechanism (OS1, OS2) is provided between the second protrusion (20b) and the output shaft (52). The oil supply mechanism (OS1, OS2) supplies oil in the space (16) to the body (20a) through the oil inlet (20i) in response to the relative rotation between the second protrusion (20b) and the output shaft (52).

5. The transmission device according to claim 4, characterized in that, The differential (20) has a planetary gear support (Bp2) that supports the planetary gear (P) so that it can rotate freely. The sidewall (20as) integrally has a cylindrical portion (20At) surrounding the second protrusion (20b). The inner circumference of the member (55) arranged axially adjacent to the planetary gear support (Bp2) is fitted and fixed to the outer circumference of the cylindrical part (20At). A cavity (56) is formed between the mating surfaces of the inner periphery of the component (55) and the outer periphery of the cylindrical portion (20At), the cavity (56) communicates with the planetary gear support portion (Bp2), and a connecting hole (57) is formed in the cylindrical portion (20At) to connect the cavity (56) with the inner periphery of the cylindrical portion (20At).

6. The transmission device according to any one of claims 1 to 5, characterized in that, The second unit support bearing (Bc2) is mounted on the opposing end wall (12s) of the gearbox (10) opposite to the reducer (R). The second unit support bearing (Bc2) is used to support the transmission unit (U) on the gearbox (10), and the second unit support bearing (Bc2) is located on the other side of the axial direction. The inner surface of the opposing end wall (12s) is formed approximately along the virtual plane of the oil reservoir (O) and orthogonal to the rotation axis (X1) of the transmission unit (U). The first oil guide (G1) includes an oil capturing section (40) and an oil guiding section (41). The oil capturing section (40) is positioned radially outward on the revolution trajectory and is capable of capturing the oil stirred up by the large-diameter gear section (P1). The oil guiding section (41) extends from the oil capturing section (40) toward the axial direction and guides the oil captured by the oil capturing section (40) to the oil inlet (20i) or to the periphery of the oil inlet (20i). The second oil guide (G2) is provided along the inner side of the opposing end wall (12s), wherein the second oil guide (G2) receives a portion of the oil captured by the oil capture part (40) and guides the received oil to the second unit support bearing (Bc2).

7. The transmission device according to any one of claims 1 to 6, characterized in that, The differential mechanism (21) includes a pair of half-shaft gears (24) and a plurality of pinions (23). The pair of half-shaft gears (24) are arranged facing each other along the axial direction within the body (20a), and the back of each of the pair of half-shaft gears (24) is supported on the body (20a) in a manner that allows it to rotate freely about the rotation axis (X1) of the transmission unit (U). The plurality of pinions (23) mesh with the pair of half-shaft gears (24), and the back of each of the plurality of pinions (23) is supported on the body (20a) in a manner that allows it to rotate freely about a second axis (X2) orthogonal to the rotation axis (X1). An oil groove (26) is provided on the inner surface of the differential housing (20) facing the back of the half-shaft gear (24) on the opposite side of the axial direction. The oil groove (26) extends radially outward from the oil outlet (20o) and opens into the differential housing (20) on the outer side of the outer periphery of the corresponding half-shaft gear (24). The opening end (26i) of the oil tank (26) that opens into the differential box (20) is positioned such that oil that is scattered from the pinion (23) due to the rotation of the pinion (23) can be introduced.

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