Unit

Abstract

[Problem] To reduce vibration transmitted to an inverter. [Solution] A unit comprising: a planetary gear mechanism housed in a gear housing chamber; an inverter housed in an inverter housing chamber; and a connection part connecting a ring gear of the planetary gear mechanism and an inner wall of the gear housing chamber. If viewed from a radial direction, the inverter housing chamber overlaps the gear housing chamber, and if viewed from a rotational axis direction, the connection part is not arranged between a rotational center of the planetary gear mechanism and an entire boundary portion between the inverter housing chamber and the gear housing chamber.

Description

unit

[0001] The present invention relates to a unit.

[0002] Patent Documents 1 and 2 disclose drive units for electric vehicles that have planetary gear mechanisms.

[0003] International Publication No. 2021 / 137281 Japanese Patent Application Laid-Open No. 2011-252532

[0004] In the above-described units, the inverter housing chamber is often arranged so as not to overlap with the gear housing chamber in the radial direction. However, there are also cases where the inverter housing chamber overlaps with the gear housing chamber in the radial direction. In such cases, vibrations generated in the planetary gear mechanism are transmitted to the inverter via the connection between the ring gear and the gear housing chamber and the boundary between the inverter housing chamber and the gear 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 has a planetary gear mechanism housed in a gear accommodating chamber, an inverter housed in an inverter accommodating chamber, and a connection portion connecting the ring gear of the planetary gear mechanism to the inner wall of the gear accommodating chamber, wherein when viewed from the radial direction, the inverter accommodating chamber overlaps with the gear accommodating chamber, and when viewed from the rotation axis direction, the connection portion is not located between the center of rotation of the planetary gear mechanism and the entire area of ​​the boundary between the inverter accommodating chamber and the gear accommodating chamber.

[0007] In the above-described aspect, the connecting portion is not disposed at a position on the ring gear closest to the inverter accommodating chamber, which increases the distance over which vibrations are transmitted from the connecting 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 a first embodiment of the present invention. FIG. 2 is a schematic diagram of the periphery of a planetary gear mechanism as viewed in the direction of arrow II in FIG. 1 . FIG. 3 is a diagram showing a first modified example of the unit according to the first embodiment. FIG. 4 is a diagram showing a second modified example of the unit according to the first embodiment. FIG. 5 is a diagram showing a third modified example of the unit according to the first embodiment. FIG. 6 is a skeleton diagram of a unit according to a second embodiment of the present invention. FIG. 7 is a schematic diagram of the periphery of the planetary gear mechanism as viewed in the direction of arrow VII in FIG. 6 . FIG. 8 is a diagram for explaining a first aspect of the fastening structure. FIG. 9 is a diagram for explaining a second aspect of the fastening structure. FIG. 10 is a diagram for explaining a third aspect of the fastening structure. FIG. 11 is a diagram showing a first modified example of the unit according to the second embodiment. FIG. 12 is a diagram showing a second modified example of the unit according to the second embodiment.

[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] First Embodiment FIG. 1 is a skeleton diagram of a unit 100 according to a first 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 therein 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 so as not to be rotatable.

[0015] The inverter 2 is accommodated in an inverter accommodating chamber 20 of the case 1. The inverter accommodating chamber 20 is provided so as to overlap at least the gear accommodating chamber 17 when viewed in the radial direction. In this embodiment, the inverter 2 and the inverter accommodating chamber 20 overlap with the motor 3, the differential mechanism 4, the planetary gear mechanism 5, and motor bearings 7 and 8 that support the motor shaft 31 of the motor 3 when viewed in the radial direction.

[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 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.

[0019] The motor 3 has a rotor 32 and a stator 33. The rotor 32 has a motor shaft 31. The rotor 32 is supported by the case 1 via motor bearings 7 and 8. The stator 33 is fastened to the inner wall of the motor housing chamber 11 by a plurality of bolts 9.

[0020] The motor bearing 8 is supported by a bearing retainer 10. The bearing retainer 10 is fastened to the inner wall of the motor housing chamber 11 by a plurality of bolts 12. 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.

[0021] 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.

[0022] 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.

[0023] The sun gear S is connected to the motor shaft 31. 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.

[0024] Fig. 2 is a schematic diagram of the planetary gear mechanism 5 and its surroundings as viewed in the direction of arrow II in Fig. 1. In Fig. 2, some components are omitted for ease of understanding.

[0025] As shown in Fig. 2, the unit 100 has a plurality of mount members 15 provided on the outer wall of the case 1. The plurality of mount members 15 connect the case 1 to the vehicle body 300. The number of the plurality of mount members 15 is set appropriately. In the example shown in Fig. 2, the number of mount members 15 is two. Furthermore, the number of pinion gears P of the planetary gear mechanism 5 is three.

[0026] The inverter accommodating chamber 20 is connected to the gear accommodating chamber 17 by bolting via a plurality of mounting portions 18 formed on the outer wall side of the case 1 .

[0027] The unit 100 also has a connection portion that connects the ring gear R of the planetary gear mechanism 5 to the inner wall of the gear accommodating chamber 17. That is, the ring gear R is fixed to the inner wall of the gear accommodating chamber 17 by the connection portion. The connection portion can be formed as a spline structure 50, for example, as shown in FIG. 2 .

[0028] The spline structure 50 has a plurality of spline teeth 51 formed on the outer periphery of the ring gear R and a plurality of spline grooves 52 formed on the inner wall of the gear accommodating chamber 17 .

[0029] 1 , in this embodiment, the inverter accommodating chamber 20 is disposed so as to radially overlap with the gear accommodating chamber 17. In this case, vibrations generated in the planetary gear mechanism 5 are transmitted to the inverter 2 via the connection between the ring gear R and the gear accommodating chamber 17 and the boundary between the inverter accommodating chamber 20 and the gear accommodating chamber 17.

[0030] 2 , when viewed from the direction of the rotation axis X, the spline structure 50 serving as a connection is not disposed between the rotation center (rotation axis X) of the planetary gear mechanism 5 and the entire area of ​​the boundary between the inverter accommodating chamber 20 and the gear accommodating chamber 17. In the example shown in FIG. 2 , the boundary is the base region of the mounting portion 18. The boundary forms a vibration transmission path from the spline structure 50 to the inverter accommodating chamber 20.

[0031] That is, a toothless portion 53 is formed on the outer periphery of the ring gear R as a non-connecting portion where the spline structure 50 is not present, and when viewed from the direction of the rotation axis X, the toothless portion 53 is located between the rotation center of the planetary gear mechanism 5 and the entire boundary between the inverter accommodating chamber 20 and the gear accommodating chamber 17. In other words, when the inverter accommodating chamber 20 and the ring gear R overlap in the radial direction, when the outer periphery in the radial direction is viewed from the rotation center of the planetary gear mechanism 5, the entire boundary between the inverter accommodating chamber 20 and the gear accommodating chamber 17 does not overlap with the connecting portion. Note that the spacing (circumferential length) between adjacent spline teeth 51 in the spline structure 50 is smaller than the circumferential length of the toothless portion 53. That is, the space between adjacent spline teeth 51 in the spline structure 50 is not a toothless portion 53.

[0032] The non-connected portion (the missing tooth portion 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, one missing tooth portion 53 is provided.

[0033] As described above, in the unit 100 of this embodiment, the connection portion is not disposed at the position on the ring gear R 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. This makes it possible to reduce vibration transmitted to the inverter 2.

[0034] When the connection portion is formed as a spline structure 50, the above structure can be provided by forming a toothless portion 53 where no spline structure 50 is provided.

[0035] Next, a first modification of the unit 100 according to the first embodiment will be described.

[0036] FIG. 3 is a diagram showing a first modified example of the unit 100 according to the first embodiment. Some components are omitted from FIG. 3 to facilitate understanding. In the example shown in FIG. 3, there are two mount members 15. The planetary gear mechanism 5 has three pinion gears P. The planetary gear mechanism 5 also has one missing tooth portion 53.

[0037] 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, a toothless portion 53 is arranged between the rotation center of the planetary gear mechanism 5 and the entire area of ​​the boundary between the inverter accommodating chamber 20 and the gear accommodating chamber 17.

[0038] 3, the connecting portion is not disposed at the position on the ring gear R closest to the inverter accommodating chamber 20. This increases the distance over which vibration is transmitted from the connecting portion to the inverter accommodating chamber 20. This reduces the vibration transmitted to the inverter 2.

[0039] In the example shown in Fig. 3, the side where the inverter accommodating chamber 20 is arranged with respect to the rotation center of the planetary gear mechanism 5 (in Fig. 3, the side above the dashed dotted line passing through the rotation axis X) is defined as a first side, and the side where the inverter accommodating chamber 20 is not arranged with respect to the rotation center of the planetary gear mechanism 5 (in Fig. 3, the side below the dashed dotted line passing through the rotation axis X) is defined as a second side, and the example shown in Fig. 3 differs from the example shown in Fig. 2 in that the spline structure 50 is arranged on both the first side and the second side. In the example shown in Fig. 2, the spline structure 50 is arranged only on the second side.

[0040] When the influence of vibration of the planetary gear mechanism 5 is taken into consideration, it is preferable to provide a connection portion only on the second side as in the example shown in Figure 2, 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 as in the example shown in Figure 3, it is possible to achieve both support performance for the ring gear R and vibration reduction.

[0041] Next, a second modification of the unit 100 according to the first embodiment will be described.

[0042] Fig. 4 is a diagram showing a second modified example of the unit 100 according to the first embodiment. Some components are omitted from Fig. 4 to facilitate understanding. In the example shown in Fig. 4, there are two mount members 15. The planetary gear mechanism 5 has three pinion gears P. The planetary gear mechanism 5 also has one missing tooth portion 53.

[0043] 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 missing tooth portion 53 is disposed between the rotation center of the planetary gear mechanism 5 and the entire area of ​​the boundary between the inverter accommodating chamber 20 and the gear accommodating chamber 17.

[0044] 4, the connecting portion is not disposed at the position on the ring gear R closest to the inverter accommodating chamber 20. This increases the distance over which vibration is transmitted from the connecting portion to the inverter accommodating chamber 20. This reduces the vibration transmitted to the inverter 2.

[0045] In the example shown in FIG. 4, similarly to the example shown in FIG. 3, the spline structure 50 is arranged on both the first side and the second side.

[0046] Therefore, it is possible to achieve both the support performance of the ring gear R and the reduction of vibrations.

[0047] Here, from the viewpoint of reducing vibration, it is preferable that the spline structure 50 on the first side be positioned outside the V-shaped area formed by the boundary line (dash-dotted line) passing through the joint (mounting portion 18) between the inverter accommodating chamber 20 and the gear accommodating chamber 17 and the center of revolution (rotation axis X) of the pinion gear P, and it is more preferable that it be positioned outside the joint between the inverter accommodating chamber 20 and the gear accommodating chamber 17 (outside the two dotted lines).

[0048] In the example shown in FIG. 4, the spline structure 50 on the first side is disposed outside the joint between the inverter accommodating chamber 20 and the gear accommodating chamber 17 (outside the two dotted lines).

[0049] In the example shown in FIG. 4, the planetary gear mechanism 5 has three pinion gears P, and the arrangement angle α of the toothless portion 53 is equal to or smaller than the smallest arrangement angle β of the three pinion gears P.

[0050] The "arrangement angle of the toothless portion 53" refers to the angle of the apex of the triangle formed by connecting the rotation center of the planetary gear mechanism 5 and the two boundary points between the toothless portion 53 and the spline structure 50 (both circumferential ends of the toothless portion 53).

[0051] The "arrangement angle of the pinion gear P" means the angle of the vertex of the triangle formed by connecting the center of rotation of the planetary gear mechanism 5, the vertex of the meshing between one pinion gear P and the ring gear R, and the vertex of the meshing between another pinion gear P adjacent to the one pinion gear P and the ring gear R, with the center of rotation as the vertex.

[0052] The "minimum arrangement angle of the pinion gear P" means that when multiple pinion gears P are arranged at equal intervals, the arrangement angles of adjacent pinion gears P are all the same and can be evaluated as the minimum. When multiple pinion gears P are arranged at non-equidistant intervals, the "minimum arrangement angle of the pinion gear P" means the smallest arrangement angle of adjacent pinion gears P.

[0053] Comparing the case where the pinion gear P is positioned facing the toothless portion 53 with the case where the pinion gear P is positioned facing the spline structure 50 during the revolution of the pinion gear P, the pinion gear P has higher support performance when it is positioned facing the spline structure 50. Therefore, it is preferable that as many of the pinion gear P as possible be positioned facing the spline structure 50 during the revolution of the pinion gear P.

[0054] Therefore, by setting the arrangement angles α and β as described above, two adjacent pinion gears P will not face one missing tooth portion 53 at the same time, and it is possible to suppress a decrease in the support performance of the pinion gear P during revolution.

[0055] 4, three pinion gears P are arranged at equal intervals in the circumferential direction. Therefore, the arrangement angle α of the toothless portions 53 is 360 / 3° or less. In this way, when N pinion gears P are arranged at equal intervals in the circumferential direction, by setting the arrangement angle α of the toothless portions 53 to 360 / N° or less, it is possible to suppress a decrease in the support performance of the pinion gears P during revolution.

[0056] Next, a third modification of the unit 100 according to the first embodiment will be described.

[0057] Fig. 5 is a diagram showing a third modified example of the unit 100 according to the first embodiment. Some components are omitted from Fig. 5 to facilitate understanding. In the example shown in Fig. 5, there are two mount members 15. The planetary gear mechanism 5 has three pinion gears P. The planetary gear mechanism 5 also has one missing tooth portion 53.

[0058] 5, the inverter accommodating chamber 20 is integrally formed with the gear accommodating chamber 17. The other configurations are the same as those of the example shown in FIG.

[0059] 2, when viewed from the direction of the rotation axis X, the toothless portion 53 is disposed between the rotation center of the planetary gear mechanism 5 and the entire area of ​​the boundary between the inverter accommodating chamber 20 and the gear accommodating chamber 17. 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.

[0060] 5 , the connecting portion is not disposed at the position on the ring gear R closest to the inverter accommodating chamber 20. This increases the distance over which vibration is transmitted from the connecting portion to the inverter accommodating chamber 20. This reduces the vibration transmitted to the inverter 2.

[0061] In the example shown in FIG. 5, similarly to the example shown in FIG. 3, the spline structure 50 is arranged on both the first side and the second side.

[0062] Therefore, it is possible to achieve both the support performance of the ring gear R and the reduction of vibrations.

[0063] In the example shown in FIG. 5 , from the viewpoint of reducing vibration, the spline structure 50 on the first side is preferably positioned outside the V-shaped area formed by the boundary line (dash-two-dot line) passing through the joint between the inverter accommodating chamber 20 and the gear accommodating chamber 17 (the entire area from the bottom surface of the inverter accommodating chamber 20 to the ends of both side walls) and the center of revolution (rotation axis X) of the pinion gear P, and more preferably positioned outside the joint between the inverter accommodating chamber 20 and the gear accommodating chamber 17 (outside the two dotted lines).

[0064] In the example shown in FIG. 5, the spline structure 50 on the first side is disposed outside the joint between the inverter accommodating chamber 20 and the gear accommodating chamber 17 (outside the two dotted lines).

[0065] In the example shown in FIG. 5, the planetary gear mechanism 5 has three pinion gears P, and the arrangement angle α of the toothless portion 53 is equal to or smaller than the smallest arrangement angle β of the three pinion gears P.

[0066] Therefore, two adjacent pinion gears P do not face one toothless portion 53 at the same time, and a decrease in the support performance of the pinion gears P during revolution can be suppressed.

[0067] Second Embodiment Next, a second embodiment of the present invention will be described.

[0068] Fig. 6 is a skeleton diagram of a unit 200 according to a second embodiment of the present invention. As shown in Fig. 6, in the unit 200 of the second embodiment, the connection portion that connects the ring gear R of the planetary gear mechanism 5 to the inner wall of the gear accommodating chamber 17 is formed as a fastening structure 60 that connects the ring gear R to the inner wall of the gear accommodating chamber 17 via a bolt 16 as a fastening member. The other configurations are the same as those of the unit 100 of the first embodiment.

[0069] The "fastening structure" refers to a protrusion protruding from the outer wall of the ring gear R and / or a protrusion protruding from the inner wall of the gear accommodating chamber 17, and the ring gear R and the gear accommodating chamber 17 are connected by inserting a fastening member (e.g., a bolt) into the protrusion.

[0070] Fig. 7 is a schematic diagram of the periphery of the planetary gear mechanism 5 as viewed in the direction of arrow VII in Fig. 6. Some components are omitted from Fig. 7 to facilitate understanding. Fig. 8 is a diagram for explaining a first embodiment of the fastening structure 60. Fig. 9 is a diagram for explaining a second embodiment of the fastening structure 60. Fig. 10 is a diagram for explaining a third embodiment of the fastening structure 60.

[0071] In the unit 200, the number of mount members 15 and the number of pinion gears P are set appropriately. In the example shown in Fig. 7, the number of mount members 15 is two. Also, the number of pinion gears P of the planetary gear mechanism 5 is three.

[0072] 7 , the fastening structure 60 is two protrusions 61 protruding from the outer wall of the ring gear R. The ring gear R and the gear accommodating chamber 17 are connected by inserting a bolt 16 into a hole provided in the protrusion 61 and fastening the bolt 16 to an internal thread formed in the gear accommodating chamber 17.

[0073] The fastening structure 60 may be a protrusion 61 protruding from the outer wall of the ring gear R as shown in Figures 7 and 8, or a protrusion 62 protruding from the inner wall of the case 1 as shown in Figure 9, or a protrusion 64 protruding from the inner wall of the case 1 and a protrusion 63 protruding from the outer wall of the ring gear R as shown in Figure 10. In the example shown in Figure 10, the protrusion 64 is internally threaded, but the protrusion 63 may also be internally threaded.

[0074] In the example shown in FIG. 7 , when viewed from the direction of the rotation axis X, the fastening structure 60 as a connection portion is not disposed between the rotation center of the planetary gear mechanism 5 and the entire area of ​​the boundary portion between the inverter accommodating chamber 20 and the gear accommodating chamber 17.

[0075] That is, a toothless portion 53 is formed on the outer periphery of the ring gear R as a non-connected portion where no fastening structure 60 exists, and when viewed from the direction of the rotation axis X, the toothless portion 53 is disposed between the rotation center of the planetary gear mechanism 5 and the entire area of ​​the boundary between the inverter accommodating chamber 20 and the gear accommodating chamber 17. In other words, when the inverter accommodating chamber 20 and the ring gear R overlap in the radial direction, when the outer periphery in the radial direction is viewed from the rotation center of the planetary gear mechanism 5, the entire area of ​​the boundary between the inverter accommodating chamber 20 and the gear accommodating chamber 17 does not overlap with the connected portion.

[0076] The non-connected portions (tooth-missing 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. 7, two tooth-missing portions 53 are provided.

[0077] 7 , no connecting portion is disposed at the position on the ring gear R closest to the inverter accommodating chamber 20. This increases the distance over which vibration is transmitted from the connecting portion to the inverter accommodating chamber 20. This reduces the vibration transmitted to the inverter 2.

[0078] When the connection portion is formed as the fastening structure 60, the above structure can be provided by forming the toothless portion 53 where the fastening structure 60 is not provided.

[0079] Next, a first modification of the unit 200 according to the second embodiment will be described.

[0080] Fig. 11 is a diagram showing a first modified example of the unit 200 according to the second embodiment. Some components are omitted from Fig. 11 to facilitate understanding. In the example shown in Fig. 11, the number of mount members 15 is two. Furthermore, the number of pinion gears P of the planetary gear mechanism 5 is three.

[0081] 11, the fastening structure 60 is three protrusions 61 protruding from the outer wall of the ring gear R. In addition, the number of missing tooth portions 53 is three.

[0082] In the example shown in FIG. 11 , similarly to the example shown in FIG. 7 , when viewed from the direction of the rotation axis X, the missing tooth portion 53 is disposed between the rotation center of the planetary gear mechanism 5 and the entire area of ​​the boundary between the inverter accommodating chamber 20 and the gear accommodating chamber 17.

[0083] 11 , the connecting portion is not disposed at the position on the ring gear R closest to the inverter accommodating chamber 20. This increases the distance over which vibration is transmitted from the connecting portion to the inverter accommodating chamber 20. This reduces the vibration transmitted to the inverter 2.

[0084] When the connection portion is formed as a fastening structure 60, as in the example shown in Fig. 11, it is preferable to provide three or more connection points (protrusions 61) where the ring gear R and the gear accommodating chamber 17 are connected. It is also preferable to provide the third point on the second side.

[0085] This allows the support performance of the ring gear R to be improved.

[0086] Here, from the viewpoint of improving the support performance of the ring gear R, it is preferable to arrange the multiple connection points at equal intervals in the circumferential direction. On the other hand, from the viewpoint of reducing vibration, as shown in Fig. 12 , it is preferable that the connection points on the first side be arranged outside the V-shaped region formed by the boundary line (two-dot chain line) passing through the joint (mounting portion 18) between the inverter accommodating chamber 20 and the gear accommodating chamber 17 and the center of revolution (rotation axis X) of the pinion gear P, and it is more preferable that they be arranged outside the joint between the inverter accommodating chamber 20 and the gear accommodating chamber 17 (outside the two dotted lines).

[0087] Fig. 12 is a diagram showing a second modified example of the unit 200 according to the second embodiment. Some components are omitted from Fig. 12 to facilitate understanding. In the example shown in Fig. 12, the number of mount members 15 is two. Furthermore, the number of pinion gears P of the planetary gear mechanism 5 is three.

[0088] 12, the fastening structure 60 is three protrusions 61 protruding from the outer wall of the ring gear R. In addition, the number of missing tooth portions is three.

[0089] In the example shown in Figure 12, multiple connection points are arranged outside the joint between the inverter accommodating chamber 20 and the gear accommodating chamber 17 (outside the two dotted lines) so as to be as equally spaced as possible in the circumferential direction.

[0090] This makes it possible to achieve both good support performance for the ring gear R and reduced vibration.

[0091] Furthermore, although not shown, when the connection portion is formed as a fastening structure 60, when viewed from the direction of the rotation axis X, a toothless portion 53 serving as a non-connection portion where no fastening structure 60 is provided may be arranged between the rotation center of the planetary gear mechanism 5 and the entire area of ​​the boundary between the inverter accommodating chamber 20 and the gear accommodating chamber 17, and multiple fastening structures 60 may be provided without gaps in other areas.

[0092] In this case, the same configuration as when the connection portion is formed as the spline structure 50 can be adopted for the configuration other than the connection portion, and the same effects can be obtained.

[0093] In the unit 100 according to the second embodiment, the inverter accommodating chamber 20 and the gear accommodating chamber 17 may be integrally formed, similar to the unit 100 according to the first embodiment.

[0094] The main effects of the units 100 and 200 according to the embodiments of the present invention will be summarized below.

[0095] (1) The units 100 and 200 each have a planetary gear mechanism 5 accommodated in the gear accommodating chamber 17, an inverter 2 accommodated in the inverter accommodating chamber 20, and a connection portion (spline structure 50, fastening structure 60) that connects the ring gear R of the planetary gear mechanism 5 to the inner wall of the gear accommodating chamber 17. When viewed from the radial direction, the inverter accommodating chamber 20 overlaps with the gear accommodating chamber 17. When viewed from the direction of the rotation axis X, no connection portion is located between the rotation center (rotation axis X) of the planetary gear mechanism 5 and the entire boundary between the inverter accommodating chamber 20 and the gear accommodating chamber 17.

[0096] According to this, the connection portion is not disposed at the position on the ring gear R 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.

[0097] (2) In the unit 100, the connection portion is formed as a spline structure 50 that meshes with the inner wall of the gear accommodating chamber 17, and a toothless portion 53 where the spline structure 50 does not exist is formed on the outer periphery of the ring gear R. When viewed from the direction of the rotation axis X, the toothless portion 53 is disposed between the rotation center (rotation axis X) of the planetary gear mechanism 5 and the entire boundary between the inverter accommodating chamber 20 and the gear accommodating chamber 17.

[0098] When the connection portion is formed as a spline structure 50, the above structure can be provided by forming a toothless portion 53 where no spline structure 50 is provided.

[0099] (3) In the unit 200, the connection portion is formed as a fastening structure 60 that connects to the inner wall of the gear accommodating chamber 17 via the bolt 16, and a toothless portion 53 where the fastening structure 60 does not exist is formed on the outer periphery of the ring gear R. When viewed from the direction of the rotation axis X, the toothless portion 53 is disposed between the rotation center (rotation axis X) of the planetary gear mechanism 5 and the entire boundary between the inverter accommodating chamber 20 and the gear accommodating chamber 17.

[0100] When the connection portion is formed as the fastening structure 60, the above structure can be provided by forming the toothless portion 53 where the fastening structure 60 is not provided.

[0101] (4) The planetary gear mechanism 5 has a plurality of pinion gears P that mesh with the ring gear R, and the arrangement angle α of the toothless portion 53 is equal to or smaller than the smallest arrangement angle β of the plurality of pinion gears P.

[0102] This prevents two adjacent pinion gears P from facing one toothless portion 53 at the same time, and reduces the deterioration of the support performance of the pinion gears P during revolution.

[0103] (5) In the units 100 and 200, the side where the inverter accommodating chamber 20 is located relative to the rotation center (rotation axis X) of the planetary gear mechanism 5 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 planetary gear mechanism 5 is defined as the second side. Connection portions (spline structure 50, fastening structure 60) are arranged on both the first side and the second side.

[0104] When considering the influence of vibration of the planetary gear mechanism 5, 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 ring gear R and vibration reduction.

[0105] 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.

[0106] 2 to 5, 7, 11, and 12, the pinion gears P are arranged at equal intervals in the circumferential direction. However, the pinion gears P may be arranged at non-equidistant intervals in the circumferential direction.

[0107] DESCRIPTION OF SYMBOLS 2 Inverter 5 Planetary gear mechanism 16 Bolt (fastening member) 17 Gear accommodating chamber 20 Inverter accommodating chamber 50 Spline structure (connection portion) 53 Toothless portion (non-connection portion) 60 Fastening structure (connection portion) 100 Unit 200 Unit P Stepped pinion gear (pinion gear) R Ring gear X Rotation axis (center of rotation) α Arrangement angle β Minimum arrangement angle

Claims

1. A unit comprising: a planetary gear mechanism accommodated in a gear accommodating chamber; an inverter accommodated in an inverter accommodating chamber; and a connecting portion connecting a ring gear of the planetary gear mechanism to an inner wall of the gear accommodating chamber, wherein, when viewed from the radial direction, the inverter accommodating chamber overlaps with the gear accommodating chamber; and, when viewed from the direction of the rotation axis, the connecting portion is not located between the center of rotation of the planetary gear mechanism and the entire area of ​​the boundary between the inverter accommodating chamber and the gear accommodating chamber.

2. A unit as claimed in claim 1, wherein the connection portion is formed as a spline structure that meshes with the inner wall of the gear accommodating chamber, and a non-connection portion where the spline structure is not present is formed on the outer periphery of the ring gear, and when viewed from the direction of the rotation axis, the non-connection portion is located between the center of rotation of the planetary gear mechanism and the entire area of ​​the boundary portion between the inverter accommodating chamber and the gear accommodating chamber.

3. 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 gear 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 ring gear, and when viewed from the direction of the rotation axis, the non-connection portion is located between the center of rotation of the planetary gear mechanism and the entire area of ​​the boundary portion between the inverter accommodating chamber and the gear accommodating chamber.

4. A unit according to claim 2 or 3, wherein the planetary gear mechanism has a plurality of pinion gears that mesh with the ring gear, and the arrangement angle of the non-connected portion is equal to or less than the smallest arrangement angle of the plurality of pinion gears.

5. A unit as claimed in claim 1, wherein the side of the planetary gear mechanism on which the inverter accommodating chamber is located is defined as a first side, and the side of the planetary gear mechanism on which the inverter accommodating chamber is not located is defined as a second side, and the connecting portion is located on both the first side and the second side.

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