Unit

Abstract

[Problem] To reduce vibration transmitted to an inverter. [Solution] This unit includes: a motor accommodated in a motor accommodation chamber; a bearing that supports a shaft of the motor; a bearing retainer that supports the bearing; an inverter accommodated in an inverter accommodation chamber; and a connection part that connects the bearing retainer and an inner wall of the motor accommodation chamber. When viewed from the rotation axis direction, the connection part is not disposed between the rotation center of the motor and the entire boundary portion between the inverter accommodation chamber and the motor accommodation chamber.

Description

unit

[0001] The present invention relates to a unit.

[0002] Patent Documents 1 to 3 disclose drive units having bearing retainers. In particular, Patent Document 1 discloses a drive unit for an electric vehicle.

[0003] Japanese Patent Application Laid-Open No. 2020-128795 Japanese Patent Application Laid-Open No. 10-281245 Japanese Patent Application Laid-Open No. 2010-242951

[0004] In the above-described unit, vibrations generated in the motor are transmitted to the inverter via the connection between the bearing retainer and the motor housing chamber and the boundary between the motor housing chamber and the inverter housing chamber.

[0005] The present invention has been made in view of the above technical problems, and has an object to reduce vibrations transmitted to an inverter.

[0006] According to one aspect of the present invention, the unit includes a motor accommodated in a motor accommodating chamber, a bearing supporting the motor shaft, and a bearing retainer supporting the bearing, an inverter accommodated in an inverter accommodating chamber, and a connection portion connecting the bearing retainer to the inner wall of the motor accommodating chamber, and when viewed from the direction of the rotation axis, the connection portion is not located between the center of rotation of the motor and the entire area of ​​the boundary between the inverter accommodating chamber and the motor accommodating chamber.

[0007] In the above-described aspect, the connection portion is not disposed at a position on the bearing retainer closest to the inverter accommodating chamber, which increases the distance over which vibrations are transmitted from the connection portion to the inverter accommodating chamber, thereby reducing the vibrations transmitted to the inverter.

[0008] Fig. 1 is a skeleton diagram of a unit according to an embodiment of the present invention. Fig. 2 is a schematic diagram of the periphery of a bearing retainer as viewed in the direction of arrow II in Fig. 1. Fig. 3 is a diagram showing a first modified example of the unit. Fig. 4 is a diagram showing a second modified example of the unit. Fig. 5 is a diagram showing a third modified example of the unit.

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In this specification, the same elements are designated by the same reference numerals throughout.

[0010] FIG. 1 is a skeleton diagram of a unit 100 according to an embodiment of the present invention.

[0011] As shown in FIG. 1, the unit 100 includes a case 1, an inverter 2, a motor 3, a planetary gear mechanism 5 that reduces the output rotation of the motor 3 and inputs it to a differential mechanism 4, and drive shafts D1 and D2 as drive shafts.

[0012] In the unit 100, a planetary gear mechanism 5, a differential mechanism 4, and drive shafts D1 and D2 are provided along a transmission path of the output rotation around the rotation axis X of the motor 3. The rotation center of the motor 3, the planetary gear mechanism 5, the differential mechanism 4, and the drive shafts D1 and D2 is the rotation axis X.

[0013] In unit 100, the output rotation of motor 3 is decelerated by planetary gear mechanism 5 and input to differential mechanism 4, and then transmitted via drive shafts D1 and D2 to the left and right drive wheels W of the vehicle on which unit 100 is mounted.

[0014] The case 1 is made up of one or more members and houses an inverter 2, a motor 3, and power transmission mechanisms such as a differential mechanism 4 and a planetary gear mechanism 5. The case 1 is fixed to the vehicle by a mount member (not shown) so that it cannot rotate.

[0015] The inverter 2 is accommodated in an inverter accommodating chamber 20 of the case 1. In this embodiment, the inverter 2 and the inverter accommodating chamber 20 overlap, as viewed in the radial direction, with the motor 3, the differential mechanism 4, the planetary gear mechanism 5, and motor bearings (bearings) 7 and 8 that support the motor shaft (shaft) 31 of the motor 3.

[0016] "Element A and element B overlap when viewed in a predetermined direction" refers to a state in which element A and element B are aligned in a predetermined direction (axial direction, radial direction, gravity direction, etc.) and at least partially overlap when observed from the predetermined direction. "Element A and element B overlap when viewed in a predetermined direction" is synonymous with "element A and element B overlap in a predetermined direction."

[0017] In contrast, "element A and element B do not overlap when viewed in a predetermined direction" refers to a state in which element A and element B are not lined up in a predetermined direction (axial direction, radial direction, gravity direction, vehicle running direction, etc.), and there is no overlapping portion between element A and element B when observed from the predetermined direction. "element A and element B do not overlap when viewed in a predetermined direction" is synonymous with "element A and element B do not overlap in a predetermined direction."

[0018] The planetary gear mechanism 5 is accommodated in the gear accommodating chamber 17 of the case 1. The planetary gear mechanism 5 is a stepped pinion planetary gear mechanism having a sun gear S, a plurality of stepped pinion gears (hereinafter simply referred to as pinion gears) P, a carrier C that rotatably supports the plurality of pinion gears P, and a ring gear R.

[0019] The sun gear S meshes with a plurality of pinion gears P (large pinions), and the plurality of pinion gears P (small pinions) mesh with a ring gear R. The number of pinion gears P is set appropriately. The planetary gear mechanism 5 may be a stepped pinion planetary gear mechanism, a single pinion planetary gear mechanism, or a double pinion planetary gear mechanism.

[0020] The sun gear S is connected to the motor shaft 31 of the motor 3. The ring gear R is fixed to the case 1. The carrier C is connected to the differential mechanism 4. The carrier C is supported by the case 1 via carrier bearings 13 and 14.

[0021] The motor 3 is housed in a motor housing chamber 11 of the case 1. The motor 3 is electrically connected to a battery (not shown) outside the unit 100 via the inverter 2, and functions as an electric motor by receiving power from the battery. The motor 3 can also function as a generator.

[0022] The motor 3 has a rotor 32 and a stator 33. The rotor 32 has a motor shaft 31. The motor shaft 31 is supported by motor bearings 7 and 8 provided in the motor housing chamber 11. In the embodiment shown in FIG. 1 , the stator 33 is fastened to the inner wall of the motor housing chamber 11 by a plurality of bolts 9.

[0023] The motor bearing 8 is supported by a bearing retainer 10. In the embodiment shown in FIG. 1, the bearing retainer 10 is fastened to the inner wall of the motor housing chamber 11 by a plurality of bolts 12.

[0024] The bearing retainer 10 abuts against the outer ring of the motor bearing 8 in the axial direction, and supports the motor bearing 8 in the axial direction. In other words, the axial position of the motor bearing 8 is determined by the bearing retainer 10. The bearing retainer 10 is also applicable to the motor bearing 7. The bearing retainer 10 may be applied to either the motor bearing 7 or 8, or to both.

[0025] Fig. 2 is a schematic diagram of the periphery of the bearing retainer 10 as viewed in the direction of arrow II in Fig. 1. Some components are omitted from Fig. 2 for ease of understanding.

[0026] The unit 100 has a connection portion that connects the bearing retainer 10 to the inner wall of the motor accommodating chamber 11. In other words, the bearing retainer 10 is fixed to the inner wall of the motor accommodating chamber 11 by the connection portion. The connection portion can be formed as a fastening structure 40 that connects the bearing retainer 10 to the inner wall of the motor accommodating chamber 11 via bolts 12 as fastening members, for example, as shown in FIG. 2 .

[0027] The "fastening structure" refers to a hole 10a formed on the outer periphery of the bearing retainer 10 through which a fastening member (e.g., a bolt) is inserted, and a seat surface 10b formed around the hole 10a on which the fastening member is seated.

[0028] In the example shown in Fig. 2, the bearing retainer 10 and the motor housing chamber 11 are connected by inserting a bolt 12 into the hole 10a and fastening the bolt 12 to an internal thread formed in the motor housing chamber 11. In the example shown in Fig. 2, there are two fastening structures 40, which are arranged at equal intervals in the circumferential direction. In other words, the two fastening structures 40 are arranged point-symmetrically about the rotation center (rotation axis X) of the motor 3. The number of fastening structures 40 can be set as appropriate. Furthermore, the multiple fastening structures 40 may be arranged at non-equidistant intervals in the circumferential direction.

[0029] The inverter accommodating chamber 20 is connected to the case 1 by bolts via a plurality of mounting portions 18 formed on the outer wall side of the case 1 .

[0030] Therefore, vibrations generated in the motor 3 are transmitted to the inverter 2 via the connection between the bearing retainer 10 and the motor accommodating chamber 11 and the boundary between the motor accommodating chamber 11 and the inverter accommodating chamber 20 .

[0031] 2 , in order to reduce vibration transmitted from the bearing retainer 10 to the inverter 2, the fastening structure 40 serving as a connection is not disposed between the rotation center (rotation axis X) of the motor 3 and the entire boundary between the inverter accommodating chamber 20 and the motor accommodating chamber 11 when viewed from the direction of the rotation axis X. In the example shown in FIG. 2 , the boundary is the base region of the mounting portion 18. The boundary constitutes a vibration transmission path from the fastening structure 40 to the inverter accommodating chamber 20.

[0032] In other words, a non-connected portion 53 where no fastening structure 40 is present is formed on the outer periphery of the bearing retainer 10, and when viewed from the direction of the rotation axis X, the non-connected portion 53 is disposed between the rotation center of the motor 3 and the entire area of ​​the boundary between the inverter accommodating chamber 20 and the motor accommodating chamber 11. When the inverter accommodating chamber 20 and the motor accommodating chamber 11 overlap in the radial direction, when the outer periphery in the radial direction is viewed from the rotation center of the motor 3, the entire area of ​​the boundary between the inverter accommodating chamber 20 and the motor accommodating chamber 11 does not overlap with the connected portion.

[0033] The non-connected portions 53 can be provided as appropriate, taking into consideration the position, number, and range of the boundary portion. In the example shown in Fig. 2, two non-connected portions 53 are provided.

[0034] As described above, in the unit 100 of this embodiment, the connection portion is not disposed at the position of the bearing retainer 10 closest to the inverter accommodating chamber 20. This increases the distance over which vibration is transmitted from the connection portion to the inverter accommodating chamber 20. This reduces the vibration transmitted to the inverter 2.

[0035] When the connection portion is formed as the fastening structure 40, the above structure can be provided by forming a non-connection portion 53 that does not have the fastening structure 40.

[0036] Next, a first modification of the unit 100 will be described.

[0037] Fig. 3 is a diagram showing a first modified example of the unit 100. In Fig. 3, some components are omitted for ease of understanding.

[0038] In the example shown in Fig. 3, three fastening structures 40 are provided. Also, in the example shown in Fig. 3, three non-connected portions 53 are provided.

[0039] In the example shown in FIG. 3 , similarly to the example shown in FIG. 2 , when viewed from the direction of the rotation axis X, the non-connected portion 53 is arranged between the rotation center (rotation axis X) of the motor 3 and the entire area of ​​the boundary between the inverter accommodating chamber 20 and the motor accommodating chamber 11.

[0040] 3, the connection portion is not located at the position on the bearing retainer 10 closest to the inverter accommodating chamber 20. This increases the distance over which vibrations are transmitted from the connection portion to the inverter accommodating chamber 20. This reduces the vibrations transmitted to the inverter 2.

[0041] When the connection portion is formed as a fastening structure 40, it is preferable that the number of connection points at which the bearing retainer 10 and the motor accommodating chamber 11 are connected be three or more, as in the example shown in Fig. 3. Furthermore, when the side of the rotation center of the motor 3 on which the inverter accommodating chamber 20 is located (in Fig. 3, the side above the dashed dotted line passing through the rotation axis X) is defined as the first side, and the side of the rotation center of the motor 3 on which the inverter accommodating chamber 20 is not located (in Fig. 3, the side below the dashed dotted line passing through the rotation axis X) is defined as the second side, it is preferable that the third point be provided on the second side.

[0042] This improves the supporting performance of the bearing retainer 10 .

[0043] Next, a second modification of the unit 100 will be described.

[0044] Fig. 4 is a diagram showing a second modified example of the unit 100. In Fig. 4, some components are omitted for ease of understanding.

[0045] In the example shown in Fig. 4, three fastening structures 40 are provided. Also, in the example shown in Fig. 4, three non-connected portions 53 are provided.

[0046] In the example shown in FIG. 4 , similarly to the example shown in FIG. 2 , when viewed from the direction of the rotation axis X, the non-connected portion 53 is arranged between the rotation center (rotation axis X) of the motor 3 and the entire area of ​​the boundary between the inverter accommodating chamber 20 and the motor accommodating chamber 11.

[0047] 4 , the connection portion is not located at the position on the bearing retainer 10 closest to the inverter accommodating chamber 20. This increases the distance over which vibrations are transmitted from the connection portion to the inverter accommodating chamber 20. This reduces the vibrations transmitted to the inverter 2.

[0048] In the example shown in Figure 4, the side where the inverter accommodating chamber 20 is located with respect to the rotation center of the motor 3 (in Figure 4, the side above the dotted line passing through the rotation axis X) is defined as the first side, and the side where the inverter accommodating chamber 20 is not located with respect to the rotation center of the motor 3 (in Figure 4, the side below the dotted line passing through the rotation axis X) is defined as the second side, and connection portions (fastening structures 40) are located on both the first side and the second side.

[0049] When the influence of vibration is taken into consideration, it is preferable to provide a connection portion only on the second side, but by providing a connection portion on the first side as well in an area that does not overlap with the boundary portion and is less affected by vibration, it is possible to achieve both the support performance of the bearing retainer 10 and vibration reduction.

[0050] Here, when the connection portion is formed as the fastening structure 40, it is preferable to arrange the multiple connection points at equal intervals in the circumferential direction from the viewpoint of improving the support performance of the bearing retainer 10. On the other hand, from the viewpoint of reducing vibration, it is preferable to arrange the connection points on the first side outside the V-shaped area formed by the boundary line (two-dot chain line) that passes through the joint (mounting portion 18) between the inverter accommodating chamber 20 and the motor accommodating chamber 11 and the rotation center (rotation axis X) of the motor 3, as shown in Figure 4.

[0051] In the example shown in FIG. 4 , a plurality of connection points are arranged outside a V-shaped area formed by a boundary line (dash-two-dot line) passing through the joint (mounting portion 18) between the inverter accommodating chamber 20 and the motor accommodating chamber 11 and the rotation center (rotation axis X) of the motor 3, so as to be as evenly spaced as possible in the circumferential direction.

[0052] Next, a third modification of the unit 100 will be described.

[0053] Fig. 5 is a diagram showing a third modified example of the unit 100 according to the first embodiment. In Fig. 5, some components are omitted for ease of understanding.

[0054] In the example shown in Fig. 5, the inverter accommodating chamber 20 is integrally formed with the motor accommodating chamber 11. The other configurations are the same as those in the example shown in Fig. 4.

[0055] 5, as in the example shown in Fig. 2, when viewed from the direction of the rotation axis X, the non-connected portion 53 is disposed between the rotation center (rotation axis X) of the motor 3 and the entire area of ​​the boundary between the inverter accommodating chamber 20 and the motor accommodating chamber 11. In the example shown in Fig. 5, the boundary is the entire area from the bottom surface of the inverter accommodating chamber 20 to the ends of both side walls.

[0056] 5 , the connection portion is not located at the position on the bearing retainer 10 closest to the inverter accommodating chamber 20. This increases the distance over which vibrations are transmitted from the connection portion to the inverter accommodating chamber 20. This reduces the vibrations transmitted to the inverter 2.

[0057] In the example shown in FIG. 5, similarly to the example shown in FIG. 4, fastening structures 40 are arranged on both the first side and the second side.

[0058] Therefore, it is possible to achieve both the supporting performance of the bearing retainer 10 and the reduction of vibration.

[0059] 5, similar to the example shown in FIG. 4, multiple connection points are arranged outside the V-shaped area formed by the boundary line (two-dot chain line) passing through the joint between the inverter accommodating chamber 20 and the motor accommodating chamber 11 and the rotation center (rotation axis X) of the motor 3, so as to be as equally spaced as possible in the circumferential direction.

[0060] The main effects of the unit 100 according to the embodiment of the present invention will be summarized below.

[0061] (1) The unit 100 includes the motor 3, the motor bearing 8 supporting the motor shaft 31 of the motor 3, and the bearing retainer 10 supporting the motor bearing 8, all of which are housed in the motor housing chamber 11; the inverter 2 housed in the inverter housing chamber 20; and a connection portion (fastening structure 40) connecting the bearing retainer 10 to the inner wall of the motor housing chamber 11. When viewed from the direction of the rotation axis X, no connection portion is located between the center of rotation of the motor 3 (rotation axis X) and the entire boundary between the inverter housing chamber 20 and the motor housing chamber 11.

[0062] According to this, the connection portion is not disposed at the position of the bearing retainer 10 closest to the inverter accommodating chamber 20. This makes it possible to increase the distance over which vibration is transmitted from the connection portion to the inverter accommodating chamber 20. As a result, it is possible to reduce the vibration transmitted to the inverter 2.

[0063] (2) The connection portion is formed as a fastening structure 40 that connects to the inner wall of the motor accommodating chamber 11 via the bolt 16, and a non-connection portion 53 where the fastening structure 40 is not present is formed on the outer periphery of the bearing retainer 10. When viewed from the direction of the rotation axis X, the non-connection portion 53 is disposed between the rotation center (rotation axis X) of the motor 3 and the entire boundary between the inverter accommodating chamber 20 and the motor accommodating chamber 11.

[0064] When the connection portion is formed as the fastening structure 40, the above structure can be provided by forming a non-connection portion 53 where the fastening structure 40 is not provided.

[0065] (3) In the unit 100 (second and third variants), the side where the inverter accommodating chamber 20 is located relative to the rotation center (rotation axis X) of the motor 3 is defined as the first side, and the side where the inverter accommodating chamber 20 is not located relative to the rotation center of the motor 3 is defined as the second side. Connection portions (fastening structures 40) are arranged on both the first side and the second side.

[0066] When the influence of vibration is taken into consideration, it is preferable to provide a connection portion only on the second side, but by providing a connection portion on the first side as well in an area that does not overlap with the boundary portion and is less affected by vibration, it is possible to achieve both the support performance of the bearing retainer 10 and vibration reduction.

[0067] Although the embodiments of the present invention have been described above, the above embodiments merely illustrate some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above embodiments.

[0068] For example, in the above embodiment, the unit 100 is a single-axis drive unit equipped with a planetary gear mechanism 5. However, the unit 100 does not have to be equipped with a planetary gear mechanism 5. The unit 100 may be a two-axis drive unit or a three-axis drive unit.

[0069] 2 inverter 3 motor 8 motor bearing (bearing) 10 bearing retainer 11 motor housing 12 bolt (fastening member) 20 inverter housing 31 motor shaft (shaft) 40 fastening structure (connection portion) 53 non-connection portion 100 unit X rotation axis (center of rotation)

Claims

1. A unit comprising: a motor, a bearing supporting the motor shaft, and a bearing retainer supporting the bearing, all housed within a motor housing; an inverter housed within an inverter housing; and a connection portion connecting the bearing retainer to the inner wall of the motor housing, wherein, when viewed from the direction of the rotation axis, the connection portion is not located between the center of rotation of the motor and the entire area of ​​the boundary between the inverter housing chamber and the motor housing chamber.

2. A unit as claimed in claim 1, wherein the connection portion is formed as a fastening structure that connects to the inner wall of the motor accommodating chamber via a fastening member, and a non-connection portion where the fastening structure is not present is formed on the outer periphery of the bearing retainer, and when viewed from the direction of the rotation axis, the non-connection portion is located between the center of rotation of the motor and the entire area of ​​the boundary portion between the inverter accommodating chamber and the motor accommodating chamber.

3. A unit as claimed in claim 1 or 2, wherein the side of the motor's rotation centre on which the inverter accommodating chamber is located is defined as a first side, and the side of the motor's rotation centre on which the inverter accommodating chamber is not located is defined as a second side, and the connection parts are located on both the first side and the second side.

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