JP2019151268A - Power device - Google Patents

Abstract

To provide a power device which can inhibit occurrence of noise and does not need maintenance.SOLUTION: A power device 1 includes: an electric motor 2; an inverter INV; a transmission 5; a differential gear 6; a case 4 which houses the electric motor 2, the transmission 5, and the differential gear 6; a left axel 3A in which one end part is connected to the differential gear 6 and the other end part extends from the case 4 to be connected with the left wheel WL; and a right axel 3B in which one end part is connected to the differential gear 6 and the other end part extends from the case 4 to be connected with the right wheel WR. A conductive part 70 having conductivity is provided between at least one of the left axel 3A and the right axle 3B and the case 4. The conductive part 70 includes: conductive grease 73; and an outer periphery side conductive member 74 which is provided in the conductive grease 73 and fixed to the case 4 and an inner periphery side conductive member 75 which is provided in the conductive grease 73 and fixed to the axle so as to face the outer periphery side conductive member 74 in a radial direction.SELECTED DRAWING: Figure 3

Description

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

  Patent Document 1 discloses an electric motor that drives a left wheel and a right wheel of a vehicle, a transmission that is disposed on a power transmission path between the electric motor, the left wheel, and the right wheel, and an output that is shifted by the transmission. A power unit is described that includes a differential that distributes to a left wheel and a right wheel. In this type of power plant, noise current generated from an inverter that controls the motor is transmitted to the axle, and the axle serves as an antenna, and noise (hereinafter also referred to as radio noise) may be emitted.

  As a countermeasure against this radio noise, for example, Patent Document 2 describes that a sliding brush is disposed on a shaft element of a power transmission mechanism and is installed on a vehicle body.

JP 2002-104001 A JP, 2006-106993, A

  However, in the radio noise countermeasure described in Patent Document 2, it is necessary to separately secure a space for providing the sliding contact brush and to maintain the sliding contact brush.

  The present invention provides a power unit that does not require maintenance and can suppress the generation of noise.

The present invention
An electric motor that drives the left and right wheels of the vehicle;
An electric motor control device for controlling the electric motor;
A speed reducer disposed on a power transmission path between the electric motor and the left wheel and the right wheel;
A differential that distributes the output shifted by the speed reducer to the left wheel and the right wheel;
A case housing the electric motor, the speed reducer, and the differential;
A left axle having one end connected to the differential and the other end extending from the case and connected to the left wheel;
A right axle having one end connected to the differential device and the other end extending from the case and connected to the right wheel;
A conductive part having conductivity is provided between at least one axle of the left axle and the right axle and the case,
The conductive portion includes a conductive grease and a pair of conductive members provided in the conductive grease,
One of the pair of conductive members is fixed to the case,
The other of the pair of conductive members is fixed to the axle so as to face the one conductive member in the radial direction.

  According to the present invention, since the conductive portion having conductivity is provided between the case and the axle, it is possible to prevent noise generated from the motor control device from being radiated. Further, since the rotation of the axle is decelerated by the speed reducer, the influence of friction can be reduced. Furthermore, by using a conductive grease and a pair of conductive members, both of which are conductive, the noise current can be reliably transmitted from the axle to the case.

It is the schematic which shows the outline of a part of vehicle by which the power plant of this invention is mounted. It is sectional drawing of the power plant of one Embodiment of this invention. FIG. 3 is a cross-sectional view of a conductive portion provided in the power unit of FIG.

First, a vehicle V on which the power unit 1 of the present invention is mounted will be described with reference to FIG.
The vehicle V uses the electric motor 2 as a drive source, and is provided in an electric vehicle such as a hybrid vehicle or an electric vehicle as a front wheel drive device or a rear wheel drive device. As shown in FIG. 1, a battery B and a power unit 1 are mounted on a vehicle V, and the battery B and the electric motor 2 are electrically connected via an inverter INV that controls the electric motor 2, and the electric motor 2 and the left wheel WL are connected. And the right wheel WR are mechanically connected via a transmission 5 and a differential 6.

[Power equipment]
Hereinafter, an embodiment of a power plant 1 according to the present invention will be described with reference to FIG.
In FIG. 2, reference numerals 3 </ b> A and 3 </ b> B are left and right axles connected to the left and right wheels WL and WR, respectively, and are arranged coaxially along the vehicle width direction. The case 4 of the power unit 1 is generally formed in a substantially cylindrical shape, and includes an electric motor 2 for driving the vehicle, a transmission 5 that decelerates driving rotation of the electric motor 2, and a drive that is decelerated by the transmission 5. A differential 6 that distributes the rotation to the left and right axles 3A, 3B is disposed.

  The case 4 includes a first case 41 that accommodates the electric motor 2, and a second case 42 that accommodates 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 bottom portion of the case 4 functions as a storage portion 44 that stores the lubricating oil, and the lubricating oil is stored up to the oil level indicated by the symbol L.

[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 the left axle 3A is coupled to the inner periphery of the rotor 22, and an end portion of the first case 41 is coaxially rotatable with the left 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 left 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 left axle 3A penetrates the end wall 41a of the first case 41. The case 4 extends outward. The electric motor 2 is electrically connected to an inverter INV provided outside the case 4.

[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 pinion gears 53 that mesh with the first gear 51 and the second gear 52, and a pinion holder 54 that supports the plurality of pinion gears 53 so that they can rotate and cannot revolve. When the drive rotation of the electric motor 2 is input, the drive rotation decelerated via the pinion 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 pinion 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 pinion shaft 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 motor 2 side of the pinion shaft 53 c and meshes with the first gear 51. The small diameter gear 53 b is integrally formed on the differential device 6 side of the pinion shaft 53 c and meshes with the second gear 52. The end of the pinion shaft 53c is rotatably supported by the partition wall 43 via a bearing 55, and the end of the differential 6 side is rotated by a pinion gear support 54a of the pinion holder 54 via a bearing 56. Supported as possible.

  The transmission 5 of the present embodiment includes, for example, three pinion gears 53, and the three pinion gears 53 are arranged at equal intervals (120 ° intervals) in the circumferential direction around the first gear 51.

  The second gear 52 has a gear portion 52 a formed of an internal gear and meshes with the small-diameter gear 53 b of the pinion 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 pinion holder 54 (pinion gear support portion 54a), and the connection portion 52b is a connection means such as a spline. Is mechanically connected to the differential case 61 of the differential device 6 via

  The pinion holder 54 includes three pinion gear support portions 54 a that rotatably support the pinion shaft 53 c of the pinion gear 53 via the bearings 56, three fixing portions 54 b that are fixed to the partition wall 43, and a center portion of the pinion holder 54 ( A cylindrical part 54c formed on the inner diameter side of the pinion gear support part 54a and the fixed part 54b.

  The pinion gear support portion 54 a is different from the meshing portion M of 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 pinion gear 53. It is arranged on the 61 side. Thereby, the other end side of the pinion shaft 53c supported at one end side by the partition wall 43 via the bearing 55 is supported by the pinion gear support portion 54a via the bearing 56, so that the pinion gear 53 is appropriately supported in a both-end supported state. It becomes possible.

  The three fixing portions 54 b are located at intermediate portions of the pinion 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 pinion shaft 53 c and a support member for the pinion holder 54.

  The cylindrical 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 pinion holder 54 is used both as a support member for the pinion 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 input plate 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 rotatably supports the left axle 3 </ b> A at the inner peripheral portion, and the outer peripheral portion is rotatably supported by the pinion holder 54 via the bearing 65. The other extension portion 61 d supports the right axle 3 </ b> B rotatably at the inner peripheral portion, and the outer peripheral portion is rotatably supported by the end wall 42 a of the second case 42 via the bearing 66. . The lubricating performance of the bearing 66 is maintained by supplying the lubricating oil of the storage portion 44 that has been scraped up with the rotation of the second gear 52.

  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.

  One end of the left axle 3A is rotatably supported by a bearing 26 provided on the end wall 41a of the first case 41, and the other end is rotatably supported by an extending portion 61c of the differential case 61. . Further, a conductive portion 70 to be described later is provided between the left axle 3A and the end wall 41a further outside the bearing 26. Further, a conductive portion 70 described later is also provided between the right axle 3B and the end wall 42a.

  In the power unit 1 configured as described above, as described above, the noise current generated from the inverter INV that controls the electric motor 2 is transmitted to the left and right axles 3A and 3B, and the left and right axles 3A and 3B serve as antennas. Radio noise may be emitted. Therefore, the power unit 1 has radio noise countermeasures. Hereinafter, countermeasures against radio noise of the power unit 1 will be described.

[Radio noise countermeasures]
As shown in FIG. 2, the power unit 1 has conductive conductivity between the left axle 3 </ b> A and the end wall 41 a of the case 4 and between the right axle 3 </ b> B and the end wall 42 a of the case 4. A portion 70 is provided. The conductive portion 70 returns noise current transmitted to the left axle 3A or the right axle 3A due to its own conductivity to the case 4 and suppresses radiation noise from the left and right axles 3A, 3B. In the following description, the conductive portion 70 provided between the right axle 3A and the end wall 42a of the case 4 will be described in detail, and the left axle 3A and the end wall 41a of the case 4 having the same structure will be described. Description of the conductive portion 70 provided between the two is omitted.

  As shown in FIG. 3, the conductive portion 70 includes an inner oil seal 71 and an outer oil seal 72 that are spaced apart between the end wall 42 a of the case 4 and the right axle 3 </ b> B, and the inner oil seal 71 and the outer oil seal 71. The conductive grease 73 sealed in the space between the oil seal 72 and a pair of outer peripheral side conductive members 74 and inner peripheral side conductive members 75 provided in the conductive grease 73 are provided.

  The inner oil seal 71 is a so-called two-liquid separation type oil seal and is disposed in the vicinity of the bearing 66. The inner oil seal 71 includes a substantially T-shaped cored bar 91, an elastic member 92 that covers the cored bar 91 and includes a pair of main lips 92a and 92b that are arranged with the cored bar 91 interposed therebetween, and a main lip 92a, It comprises a pair of garter springs 93a and 93b mounted on the outer peripheral surface of 92b. In the inner oil seal 71, the main lips 92a and 92b are tightened in the radial direction with respect to the right axle 3B by garter springs 93a and 93b.

  The outer oil seal 72 includes a substantially L-shaped cored bar 94, an elastic member 95 that covers the cored bar 94 and includes a main lip 95a and a sub lip 95b, and a garter spring 96 that is attached to the outer peripheral surface of the main lip 95a. And arranged outside the inner oil seal 71 in the axial direction. In the outer oil seal 72, the main lip 95a is tightened in the radial direction with respect to the right axle 3B by a garter spring 96.

  The space between the end wall 42a of the case 4 and the right axle 3B sealed with the inner oil seal 71 and the outer oil seal 72 is filled with conductive grease 73. Therefore, noise current is transmitted from the right axle 3B to the case 4 via the conductive grease 73, and radiation noise from the right axle 3B is suppressed.

  Here, by using the inner oil seal 71 as a two-liquid separation type oil seal, the lubricating oil in the reservoir 44 that has been scraped up along with the rotation of the second gear 52 passes through the bearing 66 and becomes conductive grease 73. Can be prevented from mixing. Thereby, it can suppress that the electroconductive performance of the electroconductive part 70 deteriorates.

  Further, in the conductive grease 73, the outer peripheral side conductive member 74 provided on the end wall 42a and the inner peripheral side conductive member 75 provided on the right axle 3B have a diameter through a slight gap. It arrange | positions so that it may oppose in direction. Both the outer peripheral side conductive member 74 and the inner peripheral side conductive member 75 are copper circlips.

  By making the outer peripheral side conductive member 74 and the inner peripheral side conductive member 75 both made of copper having high conductivity, noise current can be more reliably transmitted from the right axle 3B to the case 4. Further, by making the outer peripheral side conductive member 74 and the inner peripheral side conductive member 75 both circlips, they can be easily fitted into the groove portions provided in the end wall 42a and the right axle 3B, respectively. Assembling becomes easy.

In addition, this invention is not limited to embodiment mentioned above, A deformation | transformation, improvement, etc. are possible suitably.
The power unit 1 may employ a forced lubrication method using an oil pump instead of the scraping-up type lubrication method or together with the scraping-up type lubrication method.

  This specification describes at least the following matters. In addition, although the component etc. which respond | correspond in the above-mentioned embodiment are shown in a parenthesis, it is not limited to this.

(1) an electric motor (electric motor 2) that drives a left wheel (left wheel WL) and a right wheel (right wheel WR) of the vehicle (vehicle V);
An electric motor control device (inverter INV) for controlling the electric motor;
A transmission (transmission 5) disposed on a power transmission path between the electric motor and the left and right wheels;
A differential device (differential device 6) for distributing the output decelerated by the transmission to the left wheel and the right wheel;
A case (case 4) that houses the electric motor, the transmission, and the differential;
A left axle (left axle 3A) having one end connected to the differential and the other end extending from the case and connected to the left wheel;
A power device (power device 1) comprising: a right axle (right axle 3B) having one end connected to the differential device and the other end extending from the case and connected to the right wheel;
A conductive portion (conductive portion 70) having conductivity is provided between at least one axle of the left axle and the right axle and the case.
The conductive portion includes a conductive grease (conductive grease 73) and a pair of conductive members (an outer peripheral side conductive member 74 and an inner peripheral side conductive member 75) provided in the conductive grease,
One of the pair of conductive members (the outer peripheral conductive member 74) is fixed to the case,
The other of the pair of conductive members (inner peripheral side conductive member 75) is fixed to the axle so as to face the one conductive member in the radial direction.

  According to (1), since the conductive part having conductivity is provided between the case and the axle, it is possible to prevent noise generated from the motor control device from being radiated. Further, since the rotation of the axle is decelerated by the speed reducer, the influence of friction can be reduced. Furthermore, by using a conductive grease and a pair of conductive members, both of which are conductive, the noise current can be reliably transmitted from the axle to the case.

(2) The power unit according to (1),
The conductive portion further includes a first oil seal (inner oil seal 71) and a second oil seal (outer oil seal 72) that are spaced apart from each other between the case and the axle.
The power plant, wherein the conductive grease and the pair of conductive members are provided in a space between the first oil seal and the second oil seal.

According to (2), the conductive portion further includes a first oil seal and a second oil seal that are spaced apart between the case and the axle, and the conductive grease and the pair of conductive members are the first Since it is provided in the space between the oil seal and the second oil seal, it can be prevented that the lubricating oil in the case and the conductive oil seal are mixed, and the deterioration of the conductive performance of the conductive portion can be suppressed.
(3) The power plant according to (1) or (2),
The pair of conductive members is a power unit made of copper.

  According to (3), since the pair of conductive members are made of copper having high conductivity, noise current can be more reliably transmitted from the axle to the case.

(4) The power plant according to any one of (1) to (3),
The pair of conductive members is a power device that is a circlip.

  According to (4), since a pair of electroconductive member is a circlip, an assembly | attachment can be performed easily.

DESCRIPTION OF SYMBOLS 1 Power unit 2 Electric motor 3A Left axle 3B Right axle 4 Case 5 Transmission 6 Differential device 71 Inner oil seal (first oil seal)
72 Outer oil seal (second oil seal)
73 conductive grease 74 outer peripheral side conductive member (conductive member)
75 Inner periphery side conductive member (conductive member)
INV inverter (motor control device)
WL Left wheel WR Right wheel

Claims (4)

An electric motor that drives the left and right wheels of the vehicle;
An electric motor control device for controlling the electric motor;
A speed reducer disposed on a power transmission path between the electric motor and the left wheel and the right wheel;
A differential that distributes the output shifted by the speed reducer to the left wheel and the right wheel;
A case housing the electric motor, the speed reducer, and the differential;
A left axle having one end connected to the differential and the other end extending from the case and connected to the left wheel;
A right axle having one end connected to the differential device and the other end extending from the case and connected to the right wheel;
A conductive part having conductivity is provided between at least one axle of the left axle and the right axle and the case,
The conductive portion includes a conductive grease and a pair of conductive members provided in the conductive grease,
One of the pair of conductive members is fixed to the case,
The power unit, wherein the other of the pair of conductive members is fixed to the axle so as to face the one conductive member in a radial direction. The power plant according to claim 1,
The conductive portion further includes a first oil seal and a second oil seal that are spaced apart from each other between the case and the axle.
The power plant, wherein the conductive grease and the pair of conductive members are provided in a space between the first oil seal and the second oil seal. The power plant according to claim 1 or 2,
The pair of conductive members is a power unit made of copper. It is a power unit given in any 1 paragraph of Claims 1-3,
The pair of conductive members is a power device that is a circlip.

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