Drive device

Abstract

A drive device comprises a housing, a rotating electrical machine housed within the housing, and a transmission. Lubricating oil for lubricating the transmission gears is stored at the bottom of the housing. The housing includes a refrigerant passage through which refrigerant for cooling the rotating electrical machine flows, and a reservoir adjacent to the refrigerant passage for temporarily storing lubricating oil stirred up by the transmission gears.

Description

Technical Field

[0001] The present invention relates to a driving device. Background Art

[0002] Lubricating oil is used for lubrication and cooling in speed reducers used in electric vehicles, hybrid vehicles, and the like.

[0003] JP2018-59577A discloses a power transmission device in which a heat exchanger composed of a U-shaped tube through which cooling water flows is arranged in a transmission (reducer) to perform heat exchange between lubricating oil and cooling water.

[0004] Problems to be solved by the invention

[0005] If a heat exchanger is provided in the reducer as in the prior art, the structure becomes complicated. In addition, due to the increase in the number of parts, there is a problem that the reducer becomes larger in size and heavier. Summary of the Invention

[0006] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a drive device capable of cooling lubricating oil without increasing the number of components of a speed reducer.

[0007] One embodiment of the present invention is applied to a drive device comprising a housing, a rotating electrical machine housed in the housing, and a transmission. Lubricating oil for lubricating the gears of the transmission is stored at the bottom of the housing. The housing includes a refrigerant passage through which refrigerant for cooling the rotating electrical machine flows, and a reservoir adjacent to the refrigerant passage for temporarily storing lubricating oil stirred up by the gears of the transmission.

[0008] Effects of the Invention

[0009] According to the present invention, since the reservoir portion that temporarily stores the lubricating oil is provided adjacent to the refrigerant passage of the rotating electrical machine, the lubricating oil can be cooled without increasing the number of components of the speed reducer. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a longitudinal sectional view of the vehicle drive device according to the first embodiment of the present invention.

[0011] Figure 2 This is a diagram of the speed reducer viewed toward the partition wall portion of the outer casing.

[0012] Figure 3 This is a diagram of the speed reducer viewed toward the partition wall portion of the outer casing.

[0013] Figure 4 This is a diagram of the speed reducer viewed toward the bulkhead.

[0014] Figure 5This is a diagram of the speed reducer as viewed from the bulkhead side.

[0015] Figure 6 It is a longitudinal sectional view of a vehicle drive device according to a second embodiment of the present invention.

[0016] Figure 7 This is a diagram of a speed reducer according to a second embodiment of the present invention as viewed toward the partition wall portion of an outer casing. DETAILED DESCRIPTION

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

[0018] Figure 1 It is a longitudinal sectional view of the vehicle drive device 1 according to the present embodiment.

[0019] The drive device 1 includes an electric motor 10 as a rotating electrical machine and a speed reducer 20 that reduces the speed of the electric motor 10 and transmits the speed to a driving wheel (not shown). The electric motor 10 and the speed reducer 20 are housed in a housing 50 .

[0020] Electric motor 10 includes a stator 110, a rotor 120, and a rotor shaft 130. It rotates by receiving power from a battery (not shown). Electric motor 10 also functions as a generator, generating (or regenerating) electricity using the driving force generated by the rotation of the drive wheels. Electric motor 10 can also be used in devices other than vehicles, such as drive devices for various electrical equipment and industrial machinery.

[0021] The speed reducer 20 is a transmission device having a plurality of gears and reduces the speed of rotation input from the motor 10 and transmits the reduced speed to the drive wheels.

[0022] The housing 50 includes an outer housing 51 and an inner housing 52 housed in the outer housing 51 .

[0023] The inner circumference of the outer shell 51 is formed with a motor chamber (rotating electrical machine chamber) 510 that houses the electric motor 10 and a speed reducer chamber (transmission chamber) 520 that houses the speed reducer 20. A partition wall 530 is formed between the motor chamber 510 and the speed reducer chamber 520 to separate them. A through-hole 531 is formed in the partition wall 530, through which the rotor shaft 130 of the electric motor 10 passes.

[0024] The motor chamber 510 of the outer housing 51 is a cylindrical space, and the inner housing 52 is attached to the inner circumference thereof. The motor 10 is provided inside the inner housing 52.

[0025] The inner housing 52 has a concave and convex shape formed on its outer circumference. The convex shape of the inner housing 52 is brought into close contact with the inner circumference of the outer housing 51, thereby securing the inner housing 52 to the outer housing 51. A space is formed between the concave shape of the inner housing 52 and the inner circumference of the outer housing 51. This space serves as a refrigerant passage (first refrigerant passage 61) through which the refrigerant for cooling the electric motor 10 flows.

[0026] A wall portion 525 is formed on the portion of the inner shell 52 facing the partition wall 530 and extending along the inner circumference in a manner opposite to the partition wall 530. In addition, the inner circumference (opening) of the wall portion 525 of the inner shell 52 is connected to the cylindrical flange portion 531a protruding from the through-hole 531 of the partition wall 530. A sealing component 65a is provided on the inner circumference of the wall portion 525 to prevent refrigerant leakage. Near the partition wall 530 of the inner shell 52, a fixing portion 54 is formed on the outer circumference side and extending along the outer circumference. The fixing portion 54 is configured as a convex shape that is in close contact with the inner circumference of the outer shell 51, fixing the inner shell 52 to the inner circumference of the outer shell 51.

[0027] With this structure, the space surrounded by the wall portion 525 and the fixing portion 54 of the inner shell 52 and the partition portion 530 of the outer shell 51 constitutes a refrigerant passage (second refrigerant passage 62) through which the refrigerant flows. Figure 2 Indicated by a dotted line in the figure). The fixing portion 54 has communication holes 54 a formed at predetermined intervals (eg, four) along the circumferential direction, which connect the first refrigerant passage 61 and the second refrigerant passage 62 .

[0028] The electric motor 10 is cooled by the refrigerant flowing through the first refrigerant passage 61 formed on the circumferential outer side thereof and the second refrigerant passage 62 formed on the partition wall portion 530 side.

[0029] The speed reducer 20 is composed of three shafts (a first shaft 21 , a second shaft 22 , and a third shaft 23 ) and gears fixed to the three shafts.

[0030] The first shaft 21 has a first gear 211. The first shaft 21 is connected to the rotor shaft 130 of the motor 10 and rotates together with the rotor 120 of the motor 10. The second shaft 22 is located below the first shaft 21 and has two second gears 221a and 221b. The third shaft 23 is located below the second shaft 22 and has a final gear 231. The final gear 231 includes a differential device. The third shaft 23 serves as an axle and is connected to the drive wheels. The second gear 221a meshes with the first gear 211 of the first shaft 21, and the second gear 221b meshes with the final gear 231 of the third shaft 23. Thus, the rotation of the first shaft 21 is transmitted to the third shaft 23.

[0031] The first shaft 21 , the second shaft 22 , and the third shaft 23 are rotatably supported on the inner wall of the outer housing 51 via bearings (not shown).

[0032] With this structure, the rotation of the motor 10 is transmitted to the drive wheels via the speed reducer 20 , thereby causing the vehicle to travel.

[0033] In this embodiment, the speed reducer 20 is shown as an example in which the motor 10 is decelerated by four gears, but the number and structure of the gears are not limited thereto. The speed reducer 20 can be any device that changes the speed of rotation and can also be configured as a transmission.

[0034] Figure 2 This is a diagram of the partition wall portion 530 as viewed from the speed reducer 20 side.

[0035] The partition wall portion 530 includes a first bearing portion 521 that supports the first shaft 21 , a second bearing portion 522 that supports the second shaft 22 , and a third bearing portion 523 that supports the third shaft 23 .

[0036] These bearing portions are formed to stand cylindrically from the partition wall portion 530. A plurality of ribs are provided around these bearing portions for reinforcement.

[0037] Next, the lubricating oil in the speed reducer 20 will be described.

[0038] The reducer 20 lubricates the multiple gears with lubricating oil. The lubricating oil is stored in the bottom of the reducer 20, that is, the lower part of the reducer chamber 520 in the housing 50. That is, the bottom is constituted as an oil pan 540 (see Figure 1 ).

[0039] As the vehicle travels, lubricating oil is stirred upward by final gear 231. It is then directed to second gears 221a and 221b and first gear 211. This transfers the oil along the tooth surfaces of each gear, lubricating them. Gravity then causes the oil to flow downward.

[0040] In the speed reducer 20 configured in this manner, cooling of the lubricating oil will be described.

[0041] Conventionally, there are methods for cooling the lubricating oil of the speed reducer 20 by providing an oil cooler outside the speed reducer 20 or providing a cooling water passage inside the speed reducer 20 through which a refrigerant for cooling the electric motor flows.

[0042] On the other hand, incorporating such a cooling structure complicates the structure and increases the number of components, which in turn increases the size and weight of the reducer. Furthermore, the piping for lubricating oil to flow outside the reducer 20 and the piping for cooling water to flow inside the reducer 20 require oil seals, complicating the structure and reducing maintainability.

[0043] Therefore, this embodiment is configured to cool the lubricating oil of the speed reducer 20 by the following structure.

[0044] Figure 3 This is a diagram showing the partition wall portion 530 as viewed from the speed reducer 20 side, and is a diagram for explaining the storage portion 100 .

[0045] In the present embodiment, a reservoir (reservoir tank) 100 for temporarily storing lubricating oil flowing down from above is provided on the speed reducer 20 side of the partition wall portion 530 .

[0046] The reservoir 100 is located between the first bearing 521, the second bearing 522, and the third bearing 523 of the partition 530. The reservoir 100 is composed of a portion formed upright from the partition 530 at this position and a retainer spring 58 attached to this portion.

[0047] The stopper spring 58 is a part of a parking mechanism (not shown) provided in the speed reducer 20. The parking mechanism includes a cam member for stopping the rotation of the speed reducer 20. The stopper spring 58 is a thin plate spring that applies a biasing force to the cam member.

[0048] A plurality of protrusions are formed upright on the surface of the partition wall portion 530. The ribs 56a and 56b are structures for reinforcing the partition wall portion 530. The protrusion 55a is a structure for fixing the stopper spring 58.

[0049] like Figure 1 As shown, by fixing the retaining spring 58 to the protrusion 55a, the area surrounded by the protrusions 55a, 55b and the ribs 56a, 56b is formed by the partition 530 and the retaining spring 58 facing thereto. This area functions as a reservoir 100 for temporarily storing lubricating oil stirred upward by the gears as it flows downward.

[0050] In addition, a second refrigerant passage 62 is provided on the motor chamber 510 side of the partition wall 530 (at Figure 3 In other words, the storage portion 100 on the speed reducer chamber 520 side of the partition wall 530 is arranged adjacent to the second refrigerant passage 62 provided on the motor chamber 510 side via the partition wall 530. In particular, the thin plate portion of the partition wall 530, i.e., the portion without protruding structures such as the protrusion, rib, and bearing portion ( Figure 3 (shown by hatching in the middle) is further adjacent to the second refrigerant passage 62.

[0051] Therefore, by arranging the reservoir 100, which temporarily stores the lubricating oil of the speed reducer 20, adjacent to the second refrigerant passage 62 through which the refrigerant of the electric motor 10 flows, the lubricating oil is cooled by the refrigerant. Furthermore, the lubricating oil stored in the reservoir 100 then flows downward toward the speed reducer chamber 520 through the gap between the retaining spring 58 and the partition wall 530.

[0052] Furthermore, in the present embodiment, in order to guide the lubricating oil of the speed reducer 20 to the reservoir 100 , a partition plate is provided around each gear.

[0053] Figure 4 and Figure 5 It is an explanatory diagram of a partition plate of the speed reducer 20 . Figure 4 2 is an explanatory diagram of the structure of each gear of the speed reducer 20. Figure 5 This is a diagram showing the gears of the speed reducer 20 as viewed from the motor 10 side.

[0054] A first partition plate 301 is provided radially outside the final gear 231. The first partition plate 301 has a flat surface outside the final gear 231 and is composed of a partition portion 301a that prevents scattering of lubricating oil and guides it in the rotational direction of the gear, and a fixing portion 301b.

[0055] Reference Figure 5 A second partition plate 302 is provided radially outward below the second gear 221a. The second partition plate 302 has a circumferential surface along the periphery of the second gear 221a and is composed of a partition portion 302a that prevents scattering of lubricating oil and guides it in the rotation direction of the gear, and a fixing portion 302b.

[0056] Reference Figure 4 A third partition plate 303 is provided radially outward above the second gear. The third partition plate 303 includes a partition portion 303a having a plate-shaped surface inclined toward the partition wall and guiding lubricating oil toward the partition wall portion 530, and a fixing portion 303b.

[0057] Thus, by providing the partition plate, the lubricating oil is guided to the reservoir 100 as follows. First, as Figure 4 As shown, when the terminal gear 231 rotates counterclockwise (indicated by a hollow arrow in the figure), the lubricating oil stored at the bottom of the speed reducer chamber 520 is stirred counterclockwise as the terminal gear 231 rotates.

[0058] A first partition plate 301 is provided obliquely above the final gear 231. The first partition plate 301 receives the lubricating oil and returns it to the teeth of the final gear 231. This prevents the lubricating oil from scattering due to centrifugal force and allows it to be transferred from the teeth of the final gear 231 to the teeth of the second gear 221.

[0059] like Figure 5 As shown, a circular second partition plate 302 is provided below the second gear 221a. The second partition plate 302 receives the lubricating oil from the second gear 221a, preventing it from flowing down and returning it to the teeth of the second gear 221. As a result, when the second gear 221 rotates (indicated by the hollow arrows in the figure), the lubricating oil that would otherwise fall due to gravity is stirred up above the second gear 221a.

[0060] A third partition plate 303 is provided above the second gear. The third partition plate 303 is configured to tilt downward toward the partition wall 530. Thus, lubricating oil transported upward by the rotation of the second gear 221 adheres to the surface of the partition portion 303a of the third partition plate 303 due to centrifugal force and then transfers to the surface of the partition wall 530 as the partition portion 303a tilts.

[0061] The lubricating oil flows downward along the surface of the partition wall 530. That is, the lubricating oil flows downward around the first bearing portion 521 and the second bearing portion 522 on the surface of the partition wall 530. Figure 2 As shown, ribs 56 a and 56 b are formed in the longitudinal direction (vertical direction) on the partition wall portion 530 side of the reservoir 100 , so that lubricating oil flowing down from above is guided toward the reservoir 100 and stored in the reservoir 100 .

[0062] The reservoir 100 is adjacent to the second refrigerant passage 62 via the partition 530. Therefore, while the lubricating oil is retained in the reservoir 100, it is cooled by the refrigerant in the second refrigerant passage 62. Furthermore, because the reservoir 100 has transverse (horizontal) ribs 101a and 101b formed on the partition 530 side, the surface area on the partition 530 side is increased. This facilitates cooling of the lubricating oil by the refrigerant.

[0063] Thereafter, the lubricating oil stored in the reservoir 100 flows downwardly into the speed reducer chamber 520 through a gap between the retainer spring 58 and the partition wall 530 .

[0064] As described above, the drive device 1 according to the first embodiment of the present invention includes: a housing 50, whose bottom portion (oil pan 540) stores lubricating oil for the speed reducer 20; and a rotating electrical machine (motor 10) and a transmission (speed reducer 20) housed in the housing 50. The housing 50 includes a refrigerant passage (second refrigerant passage 62) through which refrigerant for cooling the motor 10 flows; and a reservoir 100, adjacent to the second refrigerant passage 62, which temporarily stores lubricating oil stirred up by the gears of the speed reducer 20 (first gear 211, second gear 221, and final gear 231).

[0065] Thus, since the reservoir 100 is provided adjacent to the second refrigerant passage 62 for cooling the electric motor 10, the lubricating oil can be cooled without adding a complex structure such as a heat exchanger to the speed reducer 20. Therefore, the lubricating oil can be cooled without increasing the number of components of the speed reducer 20, thereby preventing the speed reducer 20 from increasing in size and weight.

[0066] Furthermore, by temporarily storing the lubricating oil in the reservoir 100 during driving, the oil level at the bottom (oil pan 540) of the speed reducer chamber 520 can be lowered. This reduces the agitation resistance of the lubricating oil and reduces the heat generated by the lubricating oil, thereby promoting the cooling of the lubricating oil.

[0067] In this embodiment, the housing 50 is composed of an outer housing 51 having a cylindrical interior and an inner housing 52 housed within the outer housing 51. The outer housing 51 includes a partition wall 530 that divides a motor chamber 510 housing the electric motor 10 from a reducer chamber 520 housing the reducer 20. The inner housing 52 is housed within the motor chamber 510. A second refrigerant passage 62 is formed between the partition wall 530 of the outer housing 51 and the inner housing 52. The second refrigerant passage 62 faces the storage portion 100 across the partition wall 530.

[0068] With such a configuration, the second refrigerant passage 62 and the reservoir portion face each other via the partition wall 530 , so that the lubricating oil is appropriately cooled.

[0069] Furthermore, in this embodiment, the inner housing 52 is fixed near the partition wall 530 of the outer housing 51 by a fixing portion 54 that is in contact with the inner portion of the outer housing 51. A first refrigerant passage 61 is formed between the inner periphery of the motor chamber 510 of the outer housing 51 and the inner housing 52, and a second refrigerant passage 62 is formed between the partition wall 530 on the motor chamber 510 side of the outer housing 51 and the inner housing 52. The first refrigerant passage 61 and the second refrigerant passage 62 are connected via a communication hole 54a formed in the fixing portion 54.

[0070] With this structure, the first refrigerant passage 61 and the second refrigerant passage 62 communicate with each other through the communication hole 54 a , so that the refrigerant can circulate between the electric motor 10 side and the partition wall portion 530 side.

[0071] In addition, this embodiment includes a parking mechanism for stopping the rotation of the speed reducer 20, and the reservoir 100 is formed by an area defined by the partition 530 and a part of the parking mechanism (the stop spring 58) fixed to the partition 530. Thus, the reservoir 100 can be formed without adding any new components.

[0072] In this embodiment, the speed reducer chamber 520 of the housing 50 includes partition plates (a first partition plate 301 , a second partition plate 302 , and a third partition plate 303 ) on the radially outer sides of the gears for guiding lubricating oil stirred up by the gears.

[0073] Thus, the lubricating oil stirred up by the gears can be guided to the reservoir 100 .

[0074] In addition, in this embodiment, the partition wall portion 530 includes the ribs 56 a and 56 b formed upright from the partition wall portion 530 . Therefore, the lubricating oil of the speed reducer flowing downward can be guided to the reservoir 100 by the ribs 56 a and 56 b .

[0075] Next, a driving device 1 according to a second embodiment of the present invention will be described.

[0076] Figure 6 and Figure 7 It is an explanatory diagram of a driving device 1 according to a second embodiment of the present invention.

[0077] Figure 7 2 is a longitudinal sectional view of the drive device 1 . Figure 7 This is an explanatory diagram of the speed reducer 20 viewed toward the partition wall portion 530 of the outer housing 51 .

[0078] The structure of the speed reducer of the second embodiment is different from that of the first embodiment. Components identical to those of the first embodiment are denoted by the same reference numerals and their descriptions are omitted.

[0079] In the second embodiment, the rotor shaft 131 of the electric motor 10 is formed as a hollow shaft. An axle 132 penetrates the inner periphery of the rotor shaft 131 .

[0080] The speed reducer 20 is composed of a planetary gear mechanism 200. The planetary gear mechanism 200 reduces the speed of rotation of the rotor shaft 131 and transmits the reduced speed to the axle 132. The planetary gear mechanism 200 is also provided with a differential device (not shown).

[0081] like Figure 7 As shown, a plurality of semicircular ribs (ribs 59 a , 59 b , 59 c ) are concentrically erected on the partition wall portion 530 of the housing 50 .

[0082] Furthermore, the partition wall 530 includes a plate 109 having an L-shaped cross section on the upper left side of the rotor shaft 131 , and the reservoir 100 is formed by a region defined by the plate 109 and the partition wall 530 .

[0083] The second embodiment configured in this manner also exhibits the same operational effects as those of the first embodiment.

[0084] That is, Figure 7As shown, the counterclockwise rotation of the planetary gear mechanism 200 (indicated by the hollow arrow in the figure) stirs the lubricating oil in the oil pan 540 at the bottom of the speed reducer chamber 520 upward. At this time, the lubricating oil enters the gaps between the semicircular ribs 59a, 59b, and 59c, and is transferred counterclockwise through the gaps in the partition wall 530 as the planetary gear mechanism 200 rotates (indicated by the arrow in the figure).

[0085] The lubricating oil transported upward is transferred to the surface of the partition wall 530 and flows down to the storage portion 100. Figure 1 As shown, second refrigerant passages 62 are formed on the back surfaces of the ribs 59a, 59b, and 59c and the back surface of the reservoir 100. Therefore, the lubricating oil transferred on the surface of the partition 530 and the lubricating oil temporarily stored in the reservoir 100 are cooled by the refrigerant.

[0086] The lubricating oil stored in the reservoir 100 then flows downward into the speed reducer chamber 520 through a gap between the plate 109 and the partition wall 530 .

[0087] Thus, even when the speed reducer structure is composed of a single-axis planetary gear mechanism 200, as in the second embodiment, the lubricating oil can be appropriately cooled without adding a complex structure such as a heat exchanger to the speed reducer 20. Therefore, the lubricating oil can be cooled without increasing the number of components of the speed reducer 20, thereby preventing the speed reducer 20 from becoming larger and heavier.

[0088] The embodiments of the present invention, the above-described embodiments, and the modified examples merely represent a part of application examples of the present invention, and are not intended to limit the technical scope of the present invention to the specific configurations of the above-described embodiments.

[0089] In the above embodiment, an electric vehicle is described as an example in which the electric motor 10 is driven by the electric power of a battery, but the present invention is not limited thereto. A series hybrid vehicle may also be provided with an engine and the electric motor 10 is driven by the electric power generated by the engine.

Claims

1. A drive device comprising: a housing, a rotating electrical machine housed in the housing, and a transmission, wherein lubricating oil for lubricating gears of the transmission is stored at the bottom of the housing, wherein: The housing comprises: a refrigerant passage through which a refrigerant for cooling the rotating electrical machine flows; a storage portion adjacent to the refrigerant passage and temporarily storing lubricating oil stirred up by the gears of the transmission; an outer shell having a cylindrical space therein; an inner housing, which is built into the outer housing, The outer housing includes a partition wall portion that divides a rotating electrical machine chamber housing the rotating electrical machine and a transmission chamber housing the transmission, and the inner housing is attached to the inner circumference of the rotating electrical machine chamber. The refrigerant passage is formed between the partition wall portion of the outer shell and the inner shell. The refrigerant passage and the storage portion are opposed to each other via the partition wall portion. The inner shell is fixed near the partition wall of the outer shell by a fixing portion in contact with the outer shell. A first refrigerant passage is formed between the inner periphery of the rotating electrical machine chamber of the outer housing and the inner housing. A second refrigerant passage is formed between the partition wall portion of the outer housing on the rotating electrical machine chamber side and the inner housing. The first refrigerant passage and the second refrigerant passage communicate with each other through a communication hole formed in the fixing portion.

2. The driving device according to claim 1, wherein: The transmission is provided with a parking mechanism for stopping the rotation of the transmission. The storage portion is composed of an area partitioned by the partition portion and a part of the parking mechanism fixed to the partition portion.

3. The driving device according to claim 1, wherein: The transmission chamber of the housing is provided with a partition plate on the radially outer side of the gear for guiding lubricating oil stirred up by the gear.

4. The driving device according to any one of claims 1 to 3, wherein: The partition wall portion is provided with a rib formed upright from the partition wall portion, The lubricating oil of the transmission flowing downward is guided to the reservoir by the ribs.

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