JP2018189135A - Power device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power device capable of scraping up liquid medium to properly lubricate a necessary portion, regardless of a rotational direction of a differential case.SOLUTION: A power device 1 includes: an electric motor 2 configured to drive a left wheel and right wheel of a vehicle; a transmission 5 arranged on a power transmission passage between the electric motor 2 and the left wheel and right wheel; a differential device 6 configured to distribute output changed by the transmission 5, to the left wheel and the right wheel; a housing 4 storing the electric motor 2, the transmission 5 and the differential device 6; and a storage part 44 provided at a bottom part of the housing 4, and configured to store lubricant, wherein a flange part 61b of a differential case 61 of the differential device 6 is positioned at the storage part 44. In the differential case 61, provided is a plurality of ribs 61f configured to scrape up lubricant to the flange part 61b. The plurality of ribs 61f respectively have first guide surfaces 61h recessed to one side of a rotational direction, and second guide surfaces 61i recessed to the other side of the rotational direction.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a power unit provided in an electric vehicle.

  An electric motor for driving the left wheel and the right wheel of the vehicle; a transmission disposed on a power transmission path between the electric motor and the left wheel and the right wheel; and an output shifted by the transmission with the left wheel and the right wheel There is known a power device including a differential device that distributes the power to the vehicle. This type of power unit is provided in an electric vehicle such as a hybrid vehicle or an electric vehicle as a front wheel driving device or a rear wheel driving device, and houses an electric motor, a transmission, and a differential device for appropriate power transmission. It is necessary to appropriately lubricate the electric motor, the transmission and the differential with the lubricating oil stored in the storage portion of the housing.

  Therefore, in Patent Document 1, a plurality of ribs (fins) that scoop up lubricating oil according to the rotation of the differential case are provided in the differential case (differing gear) of the differential device in which the flange portion is located in the storage portion. A power plant has been proposed.

JP 2012-57641 A

  However, the shape of the plurality of ribs described in Patent Document 1 is set assuming that the differential case rotates in the forward rotation direction, and the case where the differential case rotates in the reverse rotation direction is not considered. Depending on the direction of rotation of the differential case, there is a possibility that the scraping performance of the lubricating oil will change and the necessary parts cannot be properly lubricated. In addition, it is possible to provide an oil pump that forcibly supplies the lubricating oil stored in the oil tank to a portion requiring lubrication, but in this case, a space for providing the oil pump and the oil tank is required. In addition, there is a risk of increasing weight and cost.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a power device that can scrape a liquid medium and appropriately lubricate a necessary portion regardless of the rotation direction of a differential case.

In order to achieve the above object, the invention described in claim 1
An electric motor for driving the left wheel and the right wheel of the vehicle (for example, an electric motor 2 in an embodiment described later);
A transmission (for example, a transmission 5 in an embodiment described later) disposed on a power transmission path between the electric motor and the left and right wheels;
A differential device (for example, a differential device 6 in an embodiment described later) that distributes the output shifted by the transmission to the left wheel and the right wheel;
A housing for housing the electric motor, the transmission, and the differential (for example, a housing 4 in an embodiment described later);
A storage part (for example, a storage part 44 in an embodiment described later) provided at the bottom of the housing and storing a liquid medium;
A power unit (e.g., a flange portion (e.g., a flange portion 61b of an embodiment described later) of a differential case (e.g., differential case 61 of embodiment described later) of the differential device is located in the storage section. A power device 1) according to an embodiment described later,
The differential case is provided with a plurality of ribs (for example, ribs 61f, 61m, and 61n in embodiments described later) that scrape the liquid medium on the flange portion.
The plurality of ribs include a first guide surface (for example, first guide surfaces 61h and 61j in an embodiment described later) that is recessed on one side in the rotational direction and a second guide surface (for example, described later) that is recessed on the other side in the rotational direction. The second guide surfaces 61i and 61k) of the embodiment.

The invention described in claim 2
The power plant according to claim 1,
The plurality of ribs include bidirectional ribs (for example, ribs 61f in the embodiments described later) in which both the first guide surface and the second guide surface are formed.

The invention according to claim 3
The power plant according to claim 1,
The plurality of ribs include a first rib formed with the first guide surface (for example, a first rib 61m in an embodiment described later) and a second rib formed with the second guide surface (for example described later). Second rib 61n) of the embodiment,
The plurality of first ribs and the plurality of second ribs are arranged symmetrically with respect to an imaginary line (for example, an imaginary line L2 in an embodiment described later) passing through the axis of the differential device.

The invention according to claim 4
It is a power unit given in any 1 paragraph of Claims 1-3,
One end of the differential case is rotatably supported by a bearing support portion (for example, a bearing support portion 45 of an embodiment described later) of the housing via a bearing (for example, a bearing 66 of embodiment described later),
The plurality of ribs scatter the liquid medium toward the bearing support portion.

The invention described in claim 5
The power plant according to claim 4, wherein
The power unit includes a counter holder (for example, a counter holder 54 of an embodiment described later) that rotatably supports a counter gear (for example, a counter gear 53 of an embodiment described later),
The other end portion of the differential case of the differential device is rotatably supported by the counter holder via another bearing (for example, a bearing 65 in an embodiment described later),
The counter holder has a storage space (for example, a space portion S in an embodiment described later) for storing the liquid medium that has been scraped up by a rotating body (for example, a counter gear 53 in an embodiment described later),
The liquid medium is supplied to the other bearing through the storage space.

The invention described in claim 6
The power plant according to claim 4, wherein
An oil passage (for example, an oil passage 46 in an embodiment described later) for guiding the liquid medium toward the bearing is provided on the inner surface of the housing.

The invention described in claim 7
The power plant according to claim 6, wherein
The oil passage is a step portion (for example, a step portion 42b in an embodiment described later) provided on the inner surface of the housing.

  According to the first aspect of the present invention, the differential case is provided with a plurality of ribs for scooping up the liquid medium on the flange portion, and the plurality of ribs include the first guide surface that is recessed on one side in the rotational direction. And the second guide surface that is recessed on the other side in the rotational direction, so that the liquid medium can be scraped up regardless of the rotational direction of the differential case, and the liquid medium scraped up by the ribs needs to be lubricated. By supplying to, necessary parts can be properly lubricated without an oil pump or an oil tank. Further, since the first guide surface and the second guide surface are recessed, the liquid medium temporarily collected on each guide surface can be scattered by centrifugal force.

  According to the second aspect of the present invention, the plurality of ribs include bidirectional ribs in which both the first guide surface and the second guide surface are formed. The amount of scattering can be increased.

  According to the invention described in claim 3, the plurality of ribs include a first rib on which the first guide surface is formed and a second rib on which the second guide surface is formed, and the plurality of first ribs. Since the rib and the plurality of second ribs are arranged symmetrically with respect to an imaginary line passing through the axis of the differential device, when the number of rotations of the differential case is the same, a certain amount of liquid is used regardless of the rotation direction. The medium can be scraped up.

  According to the fourth aspect of the present invention, the one end portion of the differential case is rotatably supported by the bearing support portion of the housing via the bearing, and the plurality of ribs scatter the liquid medium toward the bearing support portion. Therefore, the bearing that rotatably supports the one end portion of the differential case can be lubricated by the liquid medium that the ribs scoop up.

  According to the fifth aspect of the present invention, the power unit includes a counter holder that supports the counter gear so that the counter gear can rotate, and the other end of the differential case of the differential unit is connected to the counter holder via another bearing. The counter holder is rotatably supported, and has a storage space for storing the liquid medium picked up by the rotating body, and the liquid medium is supplied to the other bearings through the storage space. The bearing that rotatably supports the other end of the differential case can be lubricated.

  According to the sixth aspect of the present invention, since the oil passage for guiding the liquid medium toward the bearing is provided on the inner surface of the housing, the lubricating performance of the bearing can be improved.

  According to the seventh aspect of the present invention, since the oil passage is a step portion provided on the inner surface of the housing, the lubricating performance of the bearing can be improved with a simple configuration.

It is sectional drawing of the power plant which concerns on one Embodiment of this invention, and is AA sectional drawing of FIG. It is the internal side view of the power unit which looked at the partition and the counter gear from the differential device side. It is the perspective view which looked at the counter gear, the 2nd gear, and the counter holder (the bearing is omitted) from the differential device side. It is BB sectional drawing of FIG. It is the perspective view which looked at the principal part of the counter holder from the counter gear side. It is a fragmentary sectional view of the power plant of FIG. 1, and is CC sectional drawing of FIG. It is a perspective view of a differential case. It is a perspective view which shows the inside of a 2nd case. It is a perspective view which shows the modification of a differential case. It is DD sectional drawing of FIG.

Hereinafter, an embodiment of a power plant 1 according to the present invention will be described with reference to FIGS.
The power unit 1 of the present embodiment uses an electric motor 2 as a driving source for driving an axle, and is provided in an electric vehicle such as a hybrid vehicle or an electric vehicle as a front wheel driving device or a rear wheel driving device.

[Power equipment]
In FIG. 1, 3 </ b> A and 3 </ b> B are left and right axles, which are arranged coaxially along the vehicle width direction. The housing 4 of the power unit 1 is generally formed in a substantially cylindrical shape, and includes an electric motor 2 for driving an axle, a transmission 5 for decelerating the driving rotation of the electric motor 2, and a drive decelerated by the transmission 5. A differential 6 for distributing the rotation to the axles 3A and 3B is arranged.

  The housing 4 includes a first case 41 that houses the electric motor 2, and a second case 42 that houses the transmission 5 and the differential device 6. A partition wall 43 is provided at the boundary between the first case 41 and the second case 42, and the partition wall 43 partitions the internal space of the first case 41 and the internal space of the second case 42. The partition wall 43 is fastened to a step portion 41 b provided on the outer peripheral portion of the first case 41 via a bolt 47. For this reason, the mating surface A1 of the first case 41 and the partition wall 43 is located closer to the first case 41 than the mating surface A2 of the first case 41 and the second case 42. The bottom portion of the housing 4 functions as a storage portion 44 that stores the lubricating oil (liquid medium), and the lubricating oil is stored up to a static oil level L shown in FIG. This static oil level L is an air gap G (a gap secured between the inner periphery of the stator 21 and the outer periphery of the rotor 22 to be described later) in order to reduce the scraping loss of the lubricating oil in the motor 2. ) Is set lower. As shown in FIG. 2, a communication port 43 a that allows the lubricating oil to flow is formed in the lower portion of the partition wall 43.

[Electric motor]
The electric motor 2 includes a stator 21 that is fixed to the inner peripheral portion of the first case 41 and a rotor 22 that is rotatably arranged on the inner peripheral side of the stator 21. A rotor shaft 23 that surrounds the outer periphery of one axle 3A is coupled to the inner periphery of the rotor 22, and the end of the first case 41 is coaxially rotatable with the axle 3A. It is supported by the wall 41a and the partition wall 43 via bearings 24 and 25. Further, one end side of the axle 3A and the rotor shaft 23 penetrates the partition wall 43 and extends into the second case 42, and the other end side of the axle 3A penetrates the end wall 41a of the first case 41 to be a housing. 4 extends outward.

[transmission]
The transmission 5 has a first gear 51 mechanically connected to the electric motor 2, and the same rotational axis as the first gear 51, and is mechanically connected to a differential case 61 of the differential device 6. A first gear 51, a plurality of counter gears 53 that mesh with the first gear 51 and the second gear 52, and a counter holder 54 that supports the counter gears 53 so as to be rotatable and non-revolving. When the driving rotation of the electric motor 2 is input from 51, the driving rotation decelerated through the counter gear 53 and the second gear 52 is output to the differential case 61 of the differential device 6.

  The first gear 51 is composed of an external gear and is formed integrally with the rotor shaft 23. The counter gear 53 includes a large-diameter gear 53a composed of an external gear, a small-diameter gear 53b composed of an external gear, and a countershaft 53c that supports the large-diameter gear 53a and the small-diameter gear 53b so as to be integrally rotatable. The large diameter gear 53 a is coupled to the counter shaft 53 c on the electric motor 2 side and meshes with the first gear 51. The small-diameter gear 53b is formed integrally with the counter shaft 53c on the differential device 6 side and meshes with the second gear 52. The counter shaft 53c is rotatably supported at the end of the motor 2 on the partition wall 43 via a bearing 55, and the end on the side of the differential 6 is connected to the counter gear support 54a of the counter holder 54 via a bearing 56. It is rotatably supported.

  As shown in FIG. 2, the transmission 5 of the present embodiment includes three counter gears 53. The three counter gears 53 are arranged at equal intervals (120 ° intervals) in the circumferential direction around the first gear 51. At least one of the three counter gears 53 is partly or wholly located in the storage unit 44 described above, and functions as a rotating body that scoops up the lubricating oil in the storage unit 44 by rotation associated with driving of the electric motor 2. ing. In the example shown in FIG. 2, the lowermost counter gear 53 disposed immediately below the first gear 51 is caused to function as a rotating body that scoops up the lubricating oil, and the scavenged lubricating oil is supplied to the two upper counter gears 53. doing. Here, assuming that the counter gear 53 rotates counterclockwise toward FIG. 2, the lubricating oil scooped up by the rotation of the lowermost counter gear 53 is mainly supplied to the counter gear located at the upper left, Furthermore, the lubricating oil scattered by the rotation of the counter gear located at the upper left is supplied sequentially to the counter gear located at the upper right.

  In the second gear 52, the gear portion 52 a is an internal gear and meshes with the small diameter gear 53 b of the counter gear 53. The second gear 52 includes a connection portion 52b extending from the gear portion 52a to the differential device 6 side across the outer peripheral side of the counter holder 54 (counter gear support portion 54a), and the connection portion 52b is connected to a spline or the like. It is mechanically connected to the differential case 61 of the differential device 6 through means. In other words, the second gear 52 includes a second gear large-diameter portion 52c that forms a connection portion 52b with the differential case 61, a second gear small-diameter portion 52d that forms a gear portion 52a that meshes with the counter gear 53, and a second gear 52a. A second gear connecting portion 52e for connecting the second gear large diameter portion 52c and the second gear small diameter portion 52d. The outer diameter of the second gear small diameter portion 52d is that of the second gear large diameter portion 52c. It is smaller than the outer diameter. Further, the second gear 52 has a lower end portion located in the storage unit 44 described above, and also functions as a rotating body that scoops up the lubricating oil in the storage unit 44 by rotation accompanying driving of the electric motor 2.

  As shown in FIGS. 3 to 5, the counter holder 54 includes three counter gear support portions 54 a that rotatably support a counter shaft 53 c of the counter gear 53 via bearings 56, and three fixed to the partition wall 43. The fixed part 54b and the bottomed cylindrical cup part 54c formed in the center part (the inner side of the counter gear support part 54a and the fixed part 54b) of the counter holder 54 are provided.

  The counter gear support portion 54 a is different from the differential device 6 in comparison with the meshing portion M between the second gear 52 mechanically connected to the differential case 61 of the differential device 6 and the small-diameter gear 53 b of the counter gear 53. It is arranged on the moving case 61 side. As a result, the counter gear 53 can be appropriately held in a both-end supported state by supporting the other end side of the counter shaft 53c supported by the partition wall 43 via the bearing 55 at one end side by the counter gear support portion 54a via the bearing 56. It becomes possible to support.

  The three fixing portions 54 b are positioned at intermediate portions of the counter gear support portions 54 a adjacent in the circumferential direction, and are fastened to the partition wall 43 through bolts 57. As a result, the partition wall 43 serves both as a support member for the counter shaft 53 c and a support member for the counter holder 54.

  The cup portion 54c surrounds the outer periphery of one axle 3A via the space portion S from the one end side to the other end side of the meshing portion M in the axial direction and on the inner peripheral side of the meshing portion M in the radial direction. A through hole 54e through which one axle 3A passes is formed in the bottom 54d on one end side. Further, the inner peripheral portion on the other end side of the cup portion 54 c supports the one end side of the differential case 61 via a bearing 65 so as to be rotatable. As a result, the counter holder 54 is used as both a support member for the counter gear 53 and a support member for the differential case 61.

[Differential equipment]
The differential device 6 distributes the drive rotation input from the second gear 52 to the differential case 61 to the left and right axles 3A and 3B, while allowing a difference in rotation between the left and right axles 3A and 3B. A case 61, a differential pinion shaft 62, a differential pinion gear 63, and left and right side gears 64A and 64B are provided.

  The differential case 61 includes a spherical differential case main body 61a that houses the differential pinion shaft 62, the differential pinion gear 63, and the left and right side gears 64A and 64B, and a radial extension from the outer periphery of the differential case main body 61a. The flange portion 61b mechanically connected to the two gears 52, and left and right extending portions 61c and 61d extending in the axial direction from both side portions of the differential case body 61a are provided. One extending portion 61 c supports one axle 3 </ b> A in an inner peripheral portion so as to be rotatable, and an outer peripheral portion is rotatably supported by a counter holder 54 via a bearing 65. The other extending portion 61d supports the other axle 3B rotatably at the inner peripheral portion, and the bearing supporting portion 45 whose outer peripheral portion is provided on the end wall 42a of the second case 42 via the bearing 66. It is supported in a rotatable manner.

  The differential pinion shaft 62 is supported by the differential case body 61a so as to face in a direction orthogonal to the axles 3A and 3B, and can rotate two differential pinion gears 63 made of bevel gears inside the differential case body 61a. I support it. That is, the differential pinion shaft 62 allows the differential pinion gear 63 to rotate while revolving the differential pinion gear 63 according to the rotation of the differential case 61.

  The left and right side gears 64A and 64B are bevel gears, are rotatably supported inside the differential case body 61a so as to mesh with the differential pinion gear 63 from both sides, and via connecting means such as a spline. It is mechanically connected to the left and right axles 3A, 3B. When the differential pinion gear 63 revolves without rotating, for example, when traveling straight, the left and right side gears 64A and 64B rotate at a constant speed, and the driving rotation is transmitted to the left and right axles 3A and 3B. Further, when driving on a curve or turning left or right, the differential pinion gear 63 rotates, whereby the left and right side gears 64A and 64B rotate relative to each other, and a rotation difference between the left and right axles 3A and 3B is allowed.

[Lubrication function of counter holder]
Next, the lubrication function of the counter holder 54 will be described.

  The counter holder 54 has a storage space in which the second gear 52 and the counter gear 53 store the lubricating oil that has been scooped up from the storage portion 44 of the housing 4. This storage space is the above-described space portion S formed by the cup portion 54c and the one axle 3A. Lubricating oil scooped up by the second gear 52 and the counter gear 53 communicates with the space portion S, which will be described later. It flows into the space S through the communication holes 54f and 54g.

  The lubricating oil that has flowed into the space portion S is disposed adjacent to the space portion S and supplied to the above-described bearing 65 that rotatably supports one end side of the differential case 61, and is appropriately lubricated. Lubricating oil is also distributed from the space S to the inside of the differential 6 that needs lubrication and the electric motor 2 that needs cooling by the lubricating oil. More specifically, the lubricating oil is supplied from the space S to the inside of the differential device 6 through the gap between the axle 3A and the extension 61c of the differential case 61, and from the space S to the axle 3A. It is supplied to the electric motor 2 side through a gap with the rotor shaft 23.

  As shown in FIG. 5, the counter holder 54 includes a first guide 54 i that receives the lubricating oil scraped up by the second gear 52 and the counter gear 53 on a first surface 54 h facing the counter gear 53. The first guide portion 54i is a protruding portion formed on both sides of the cup portion 54c and extending linearly toward the cup portion 54c, and guides the received lubricating oil to the cup portion 54c. A communication hole 54f is formed in the connection portion between the first guide portion 54i and the cup portion 54c, and the lubricating oil received by the first guide portion 54i is stored in the space S through the communication hole 54f. .

  As shown in FIG. 3, the counter holder 54 has a second guide portion 54 k that receives the lubricating oil scraped up by the second gear 52 and the counter gear 53 on the second surface 54 j facing the differential case 61 of the differential device 6. Is provided. The second guide portion 54k is a protrusion formed above the cup portion 54c and extending in an arc shape below the uppermost fixed portion 54b, and guides the received lubricating oil to the cup portion 54c. A communication hole 54g is formed in the connection portion between the second guide portion 54k and the cup portion 54c, and the lubricating oil received by the second guide portion 54k is stored in the space S through the communication hole 54g. . The communication hole 54g also communicates with the first surface 54h side of the counter holder 54.

  As shown in FIGS. 3 and 4, among the counter gear support portions 54 a of the counter holder 54, the counter gear support portion 54 a that supports the upper two counter gears 53 is the differential case 61 of the differential device 6. A pocket 54m for storing lubricating oil is provided at the opening end on the second surface 54j side that faces the surface. The pocket 54m allows appropriate lubrication of the bearing 56 by temporarily retaining the lubricating oil supplied to the counter gear support 54a.

  By the way, a part of the lubricating oil supplied from the space S to the bearing 65 passes through the bearing 65 and flows to the outer periphery of the differential case 61, receives a centrifugal force accompanying the rotation of the differential case 61, and receives a flange. It moves in the outer diameter direction along the part 61b. The flange portion 61b of the present embodiment includes a third guide portion 61e that guides lubricating oil that moves in the outer diameter direction along the flange portion 61b to the two upper counter gear support portions 54a. The third guide portion 61e is an edge portion of an annular recess formed on the surface of the flange portion 61b facing the counter gear 53, and the edge portion formed at a position facing the counter gear support portion 54a in the radial direction, The lubricating oil that moves in the outer diameter direction along the flange portion 61b is guided to the counter gear support portion 54a. A part of the lubricating oil scraped up by the second gear 52 has the same flow.

[Rib and through hole]
Next, the rib 61f and the through hole 61g provided in the differential case 61 will be described with reference to FIG.

  The flange portion 61 b of the differential case 61 has a lower end portion located in the storage portion 44 described above, and also functions as a rotating body that scoops up the lubricating oil in the storage portion 44 by the rotation accompanying the drive of the electric motor 2. Of the front and back surfaces facing the axial direction of the flange portion 61b, a plurality of ribs 61f that scoop up lubricating oil are provided on the surface facing the bearing support portion 45 described above. The differential case 61 of the present embodiment includes ten ribs 61f arranged in the circumferential direction on the surface of the flange portion 61b.

  Each rib 61f protrudes from the surface of the flange portion 61b along the radial direction, and has a first guide surface 61h recessed on one side in the rotational direction and a recess on the other side in the rotational direction on both sides in the circumferential direction. A second guide surface 61i. Specifically, the rib 61f of the present embodiment has guide surfaces 61h and 61i that are recessed in an arc shape on both sides in the circumferential direction, and a rib center line L1 that passes through the axis of the differential 6 (see FIG. 7). ).

  According to such a rib 61f, the lubricating oil in the storage portion 44 can be reliably scraped up regardless of the rotation direction of the differential case 61. Further, since the first guide surface 61h and the second guide surface 61i are recessed, the lubricating oil is temporarily collected on the guide surfaces 61h and 61i, and the collected lubricating oil can be scattered by centrifugal force. it can. Further, since the rib 61f of the present embodiment constitutes a bidirectional rib in which both the first guide surface 61h and the second guide surface 61i are formed, the first guide surface 61h and the second guide surface 61i As compared with the case of forming them on separate ribs, the number of guide surfaces 61h, 61i can be increased, and the amount of scattered lubricant can be increased.

  The first guide surface 61h and the second guide surface 61i are formed to have a predetermined gradient θ1 (see FIG. 10) without rising at a right angle from the surface of the flange portion 61b. Specifically, the angle θ2 (see FIG. 10) formed by the surface of the flange portion 61b and the guide surfaces 61h and 61i is set to be an obtuse angle. According to the rib 61f including the first guide surface 61h and the second guide surface 61i as described above, the lubricating oil collected by the guide surfaces 61h and 61i as the differential case 61 rotates is axially caused by the gradient θ1. Since it can be scattered, the lubricating oil scooped up by the rib 61f is supplied to the bearing support portion 45, and the bearing 66 that rotatably supports one end portion of the differential case 61 can be lubricated.

  The differential case 61 is disposed so as to partition the internal space of the second case 42 into one side in the axial direction and the other side in the axial direction. The level of the lubricating oil in the reservoir 44 is uniform on the front side and the back side of the differential case 61 if the power unit 1 is stationary, but in the state where the differential case 61 is rotating. Since the lubricating oil is scraped up by the rib 61f on the surface side of the differential case 61, the liquid level of the lubricating oil in the storage portion 44 becomes lower on the surface side of the differential case 61, and the lubricating oil by the rib 61f. There is a possibility that the scraping performance of the machine will be reduced.

  Therefore, the differential case 61 is provided with a through hole 61g that penetrates the front surface and the back surface of the flange portion 61b. The differential case 61 of this embodiment has six through-holes 61g arranged in the circumferential direction, and these through-holes 61g circulate lubricating oil, so that the surface side of the flange portion 61b of the differential case 61 and The difference in the liquid level height of the storage part 44 on the back side is reduced.

  The through hole 61g is provided at a position avoiding the plurality of ribs 61f in the flange portion 61b of the differential case 61. Specifically, a through hole 61g is formed so as to be positioned between adjacent ribs 61f on the surface of the flange portion 61b. According to such a differential case 61, the through-hole 61g does not hinder the function of scooping up the lubricating oil by the rib 61f, and the liquid level drop due to the scooping up of the rib 61f can be suppressed.

[Oil passage]
Next, the oil passage 46 provided in the second case 42 will be described with reference to FIG.

  An oil passage 46 is provided on the inner surface of the second case 42 to guide the lubricating oil scraped up by the plurality of ribs 61 f of the differential case 61 toward the bearing 66. The oil passage 46 of the present embodiment is a step portion 42b provided on the inner surface of the second case 42. The oil passage 46 can be configured with a simple configuration to improve the lubrication performance of the bearing 66.

  More specifically, the second case 42 of the present embodiment has a lower portion of the inner surface region facing the flange portion 61b of the differential case 61 where the lubricating oil is actively scraped up by the ribs 61f. A bulging portion 42c is provided that bulges inwardly of the case and reduces the clearance with the rib 61f, thereby improving the efficiency of scooping up the lubricating oil by the rib 61f. At both ends in the circumferential direction of the bulging portion 42 c, a step portion 42 b that is a boundary portion with the non-bulging portion 42 d is formed, and this step portion 42 b functions as the oil passage 46. That is, when the lubricating oil scraped up by the rib 61f is scattered toward the inner surface of the second case 42, the scattered lubricating oil flows down along the inner surface (non-bulged portion 42d) of the second case 42. After being received by the step portion 42b, it is supplied to the bearing 66 along the step portion 42b. The stepped portion 42b may be a slope that becomes lower toward the bearing 66.

  As described above, according to the power unit 1 of the present embodiment, the differential case 61 is provided with the plurality of ribs 61f that scoop up the lubricating oil on the flange portion 61b, and the plurality of ribs 61f are in the rotational direction. Since it has a first guide surface 61h recessed on one side and a second guide surface 61i recessed on the other side in the rotational direction, the lubricating oil can be scraped up regardless of the rotational direction of the differential case 61, By supplying the lubricating oil scooped up by the rib 61f to a portion requiring lubrication, the necessary portion can be appropriately lubricated without an oil pump or an oil tank. In addition, since the first guide surface 61h and the second guide surface 61i are recessed, the lubricating oil temporarily collected on the guide surfaces 61h and 61i can be scattered by centrifugal force.

  Further, since the plurality of ribs 61f are bidirectional ribs in which both the first guide surface 61h and the second guide surface 61i are formed, the number of the guide surfaces 61h and 61i is increased, and the amount of scattered lubricant is increased. Can do.

  Further, one end portion of the differential case 61 is rotatably supported by the bearing support portion 45 of the housing 4 via the bearing 66, and the plurality of ribs 61f scatters the lubricating oil toward the bearing support portion 45. The bearing 66 that rotatably supports one end portion of the differential case 61 can be lubricated by the lubricating oil scraped up by the rib 61f.

  Further, the power unit 1 includes a counter holder 54 that supports the counter gear 53 so as to be capable of rotating, and the other end portion of the differential case 61 of the differential device 6 is rotatable to the counter holder 54 via another bearing 65. The counter holder 54 has a space S for storing the lubricating oil scraped up by the counter gear 53, and the other bearings 65 are supplied with the lubricating oil through the space S. By using the holder 54, the bearing 65 that rotatably supports the other end of the differential case 61 can be lubricated.

  Further, since the oil passage 46 for guiding the lubricating oil toward the bearing 66 is provided on the inner surface of the housing 4, the lubricating performance of the bearing 66 can be improved.

  Further, since the oil passage 46 is the stepped portion 42b provided on the inner surface of the housing 4, the lubrication performance of the bearing 66 can be improved with a simple configuration.

[Modification]
Next, a modification of the differential case 61 will be described with reference to FIGS. However, about the same structure as the said embodiment, description of the said embodiment is used by using the same code | symbol as the said embodiment.

  As shown in FIGS. 9 and 10, the differential case 61 </ b> B according to the modification includes a plurality of first ribs 61 m formed with a first guide surface 61 j that is depressed on one side in the rotation direction, and a depression on the other side in the rotation direction. However, it is different from the differential case 61 of the above-described embodiment in that it includes a plurality of second ribs 61n on which second guide surfaces 61k are formed.

  When the number of first ribs 61m (for example, five) and the number of second ribs 61n (for example, five) are the same, and the number of rotations of the differential case 61B is the same, a fixed amount regardless of the direction of rotation. The lubricating oil can be scraped up. Further, in the differential case 61B shown in FIG. 9, the plurality of first ribs 61m and the plurality of second ribs 61n are arranged symmetrically with respect to the virtual line L2 passing through the axis of the differential device 6. In addition to the number of the first ribs 61m and the number of the second ribs 61n being equal, the plurality of first ribs 61m and the plurality of second ribs 61n can be efficiently arranged.

  Further, as shown in FIG. 10, the first guide surface 61j and the second guide surface 61k of the differential case 61B according to the modified example are also flange portions, similarly to the first guide surface 61h and the second guide surface 61i described above. It is formed so as to have a predetermined gradient θ1 without rising at a right angle from the surface of 61b. Specifically, the angle θ2 formed by the surface of the flange portion 61b and the guide surfaces 61j and 61k is set to be an obtuse angle.

In addition, this invention is not limited to embodiment mentioned above, A deformation | transformation, improvement, etc. are possible suitably.
For example, the power unit 1 may employ a forced lubrication method using an oil pump together with a scraping-type lubrication method.
Moreover, as long as it has the 1st guide surface recessed in the rotation direction one side and the 2nd guide surface recessed in the rotation direction other side, arbitrary shapes can be employ | adopted for several ribs.

DESCRIPTION OF SYMBOLS 1 Power unit 2 Electric motor 4 Housing 42b Step part 45 Bearing support part 46 Oil passage 44 Storage part 5 Transmission 53 Counter gear 54 Counter holder 6 Differential device 61, 61B Differential case 61b Flange part 61f Rib 61h 1st guide surface 61i Second guide surface 61j First guide surface 61k Second guide surface 61m First rib 61n Second rib 65 Bearing (other bearing)
66 Bearing L2 Virtual line S Space part

Claims (7)

An electric motor that drives the left and right wheels of the vehicle;
A transmission disposed on a power transmission path between the electric motor and the left and right wheels;
A differential that distributes the output shifted by the transmission to the left wheel and the right wheel;
A housing for housing the electric motor, the transmission, and the differential;
A storage part that is provided at the bottom of the housing and stores a liquid medium;
A power unit in which a flange portion of the differential case of the differential device is located in the storage unit,
The differential case is provided with a plurality of ribs for scraping the liquid medium on the flange portion,
The plurality of ribs have a first guide surface that is recessed on one side in the rotational direction and a second guide surface that is recessed on the other side in the rotational direction. The power plant according to claim 1,
The plurality of ribs includes a bidirectional rib in which both the first guide surface and the second guide surface are formed. The power plant according to claim 1,
The plurality of ribs include a first rib on which the first guide surface is formed, and a second rib on which the second guide surface is formed,
The power device, wherein the plurality of first ribs and the plurality of second ribs are arranged symmetrically with respect to an imaginary line passing through an axis of the differential device. It is a power unit given in any 1 paragraph of Claims 1-3,
One end of the differential case is rotatably supported by a bearing support portion of the housing via a bearing,
The plurality of ribs is a power unit that scatters the liquid medium toward the bearing support portion. The power plant according to claim 4, wherein
The power unit includes a counter holder that supports the counter gear so as to rotate,
The other end of the differential case of the differential device is rotatably supported by the counter holder via another bearing,
The counter holder has a storage space for storing the liquid medium scooped up by the rotating body,
The power unit, wherein the liquid medium is supplied to the other bearing through the storage space. The power plant according to claim 4, wherein
A power unit, wherein an inner surface of the housing is provided with an oil passage for guiding the liquid medium toward the bearing. The power plant according to claim 6, wherein
The oil passage is a power unit that is a step provided on an inner surface of the housing.

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