Vehicle electric unit

Abstract

This reduces the unevenness of the fastening load applied to the bolts that secure the ring gear, making the bolts less likely to loosen. [Solution] The ring gear 41 and the casing 21 are included, the ring gear 41 is fastened to the casing 21 by a plurality of bolts 50 arranged on the outer circumference 42, the casing 21 has a plurality of mounting fastening parts, the plurality of bolts 50 (51~54, 61~64) include a plurality of bolt sets 55, 65 consisting of upper and lower first bolts 51, 61 and second bolts 52, 62 arranged circumferentially on the outer circumference 42 such that the distance from the mounting fastening positions 26LA, 25LA is a first distance L1A, L1B, and a plurality of other bolts 53, 54, 63, 64 arranged on the outer circumference 42 such that the distance from the mounting fastening positions 26LA, 25LA is longer than the first distance L1A, L2A.

Description

Technical Field

[0001] The present disclosure relates to the structure of an electric unit for a vehicle.

Background Art

[0002] Patent Document 1 discloses a structure in a drive device for an electric vehicle including a plurality of motor generators and a common casing, in which bolts fastening stators of respective motors have an unequal pitch in the circumferential direction.

[0003] Patent Document 2 describes that attachment bolt holes of a ring gear of an external gear have an unequal pitch.

[0004] Patent Document 3 describes that when fastening a cross member with bolts, a uniform and stable fastening force is ensured by making the arrangement of the bolts at three points not on a straight line.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0006] Incidentally, in recent years, electric vehicle units that integrate the motor and transmission gear have been used. In these electric vehicle units, planetary gears are used as the transmission gears. The ring gear of the planetary gear is fixed to the casing with bolts to receive the meshing reaction force of the gears. The fastening load applied to these bolts is determined by the arrangement of the bolts and the rigidity balance of the surrounding parts, but if there is an imbalance in the fastening load, the bolts may loosen.

[0007] Therefore, the purpose of this disclosure is to reduce the unevenness of the fastening load applied to the bolts that fix the ring gear, thereby making the bolts less likely to loosen. [Means for solving the problem]

[0008] The electric vehicle unit of the present disclosure includes a motor for driving a vehicle, a transmission gear connected to the motor, and a casing housing the motor and the transmission gear, wherein the transmission gear includes a ring gear having a cylindrical outer circumference and a plurality of teeth projecting radially inward from the outer circumference, the ring gear being fastened to the casing by a plurality of bolts arranged on the outer circumference, the plurality of bolts being arranged at unequal pitches in the circumferential direction, the casing having a plurality of mount fastening portions being fastened to a plurality of mounts provided on the body, the plurality of bolts including a plurality of bolt sets consisting of a first bolt and a second bolt arranged circumferentially on the outer circumference such that the distance from the mount fastening position within the axial end face of the outer circumference is a first distance, and a plurality of other bolts being arranged on the outer circumference such that the distance from the mount fastening position within the axial end face of the outer circumference is longer than the first distance.

[0009] In this way, the first and second bolts are positioned near the mounting bolt fastening positions of the casing, equidistant from the mounting bolt fastening positions within the axial end face of the outer circumference, and multiple other bolts are positioned further away from the first and second bolts. This reduces the fastening load on the first and second bolts. As a result, uneven distribution of the fastening load on each bolt can be suppressed. In addition, each bolt is less likely to loosen.

[0010] In the vehicle electric unit of the present disclosure, the plurality of other bolts include a plurality of other bolt sets comprising a third bolt and a fourth bolt arranged on the outer circumference such that the distance from the mount fastening position within the axial end face of the outer circumference is a second distance greater than the first distance, wherein the third bolt is arranged in close proximity to the first bolt and the fourth bolt is arranged in close proximity to the second bolt.

[0011] In this way, by positioning the third and fourth bolts close to the first and second bolts in an area within the axial end face of the outer circumference where the distance from the mounting bolt fastening position is greater than that of the first and second bolts, the fastening load of the first and second bolts can be reduced, while the fastening load of the third and fourth bolts can be increased. This suppresses unevenness in the fastening load of each bolt. In addition, it makes it more difficult for each fastening bolt to loosen.

[0012] In the vehicle electric unit of this disclosure, the circumferential pitch between the first bolt and the third bolt, and the circumferential pitch between the second bolt and the fourth bolt are a first pitch which is the minimum length that allows each bolt to be tightened, and the circumferential pitch between the first bolt and the second bolt may be longer than the first pitch.

[0013] This allows the fastening loads of the first to fourth bolts to be equalized, thereby further suppressing the unevenness of the fastening loads of each fastening bolt. In addition, it makes each fastening bolt less likely to loosen.

[0014] In the vehicle electric unit of the present disclosure, the first bolt and the second bolt, and the third bolt and the fourth bolt may be arranged symmetrically with respect to a diameter line connecting the mount fastening position and the central axis of the ring gear within the axial end face of the outer circumference.

[0015] This allows the fastening load on the first and second bolts to be equalized, as well as the fastening load on the third and fourth bolts. By equalizing the fastening load on each bolt, each bolt becomes less likely to loosen. [Effects of the Invention]

[0016] This disclosure reduces the unevenness of the fastening load applied to the bolts that secure the ring gear, making the bolts less likely to loosen. [Brief explanation of the drawing]

[0017] [Figure 1] This is a plan view of an electric vehicle equipped with the electric unit of the embodiment. [Figure 2] This is a cross-sectional view of the electric unit of the embodiment, which is the AA section shown in Figure 1. [Figure 3] This graph shows the distribution of fastening loads on the bolts of the ring gear of the electric unit in the embodiment. [Figure 4] This is a cross-sectional view of a conventional electric unit. [Figure 5] This graph shows the distribution of fastening loads on the bolts of the ring gear in a conventional electric unit. [Modes for carrying out the invention]

[0018] Hereinafter, the structure of the vehicle electric unit 20 (hereinafter referred to as the electric unit 20) according to the embodiment will be described with reference to the drawings. Note that FR, UP, and RH shown in each figure indicate the front side, the upper side, and the right side of the electric vehicle 100 on which the electric unit 20 is mounted, respectively. Also, the opposite directions of FR, UP, and RH indicate the rear side, the lower side, and the left side. Hereinafter, when simply explaining using the directions of front and rear, left and right, and up and down, unless otherwise specified, they indicate the front and rear, left and right, and up and down of the electric vehicle 100. Also, the front and rear, left and right, and up and down of the electric unit 20 are the front and rear, left and right, and up and down of the electric vehicle 100.

[0019] As shown in FIG. 1, the body 10 of the electric vehicle 100 includes left and right side members 11L and 11R, and a cross member 12 that connects the left and right side members 11L and 11R in the vehicle width direction. At the left and right ends of the cross member 12, left and right front mounts 13L and 13R that support the front portion of the electric unit 20 are provided. Also, on the left and right side members 11L and 11R, left and right rear mounts 14L and 14R that support the rear portion of the electric unit 20 are provided. Thus, a plurality of mounts are provided on the body 10.

[0020] The electric unit 20 includes a motor 30 for vehicle drive, a transmission gear 40 connected to the motor 30, and a casing 21 that houses the motor 30 and the transmission gear 40. At the left and right front portions of the casing 21, front mount fastening portions 25L and 25R to which front mount bolts 23L and 23R are fastened are provided. Also, at the left and right of the rear portion of the casing 21, rear mount fastening portions 26L and 26R to which rear mount bolts 24L and 24R are fastened are provided.

[0021] As shown in Figure 1, the front mounting fastening portions 25L and 25R of the casing 21 are supported by the left and right front mounts 13L and 13R via the left and right front mounting bolts 23L and 23R. Similarly, the rear mounting fastening portions 26L and 26R of the casing 21 are supported by the left and right rear mounts 14L and 14R via the left and right rear mounting bolts 24L and 24R. The casing 21 is provided with a gear mounting seat 27 to which the ring gear 41, which will be described later, is attached. The gear mounting seat 27 is provided with a plurality of screw holes 28.

[0022] The gear change gear 40 is a planetary gear composed of a ring gear 41, a sun gear (not shown), and a pinion gear (not shown). The ring gear 41 is an internal gear having a cylindrical outer circumference 42 and a plurality of teeth 43 that protrude radially inward from the outer circumference 42 (see Figure 2).

[0023] As shown in Figure 1, the ring gear 41 is fixed to the casing 21 by aligning the axial end face 45 of the outer circumference 42 with the surface of the gear mounting seat 27 of the casing 21 and screwing a plurality of bolts 50 into a plurality of screw holes 28 provided in the gear mounting seat 27 from the left side. The plurality of bolts 50 consist of eight bolts, which will be described later: the upper first bolt 51, upper second bolt 52, upper third bolt 53, upper fourth bolt 54, lower first bolt 61, lower second bolt 62, lower third bolt 63, and lower fourth bolt 64.

[0024] Next, the bolt arrangement of the ring gear 41 will be described with reference to Figure 2. As shown in Figure 2, the ring gear 41 is fixed to the casing 21 by eight bolts located on the outer circumference 42: the upper first bolt 51, upper second bolt 52, upper third bolt 53, upper fourth bolt 54, lower first bolt 61, lower second bolt 62, lower third bolt 63, and lower fourth bolt 64. Here, the eight bolts, the upper first bolt 51, upper second bolt 52, upper third bolt 53, upper fourth bolt 54, lower first bolt 61, lower second bolt 62, lower third bolt 63, and lower fourth bolt 64, are arranged on a single circumference 91 with unequal pitches in the circumferential direction.

[0025] Furthermore, the front mount fastening position 25LA and the rear mount fastening position 26LA shown in Figure 2 indicate the positions of the left front mount fastening portion 25L and the left rear mount fastening portion 26L within the plane of the axial end face 45 of the outer peripheral portion 42.

[0026] First, the arrangement of the upper first bolt 51, upper second bolt 52, upper third bolt 53, and upper fourth bolt 54, which are positioned around the rear mount fastening portion 26L, will be described.

[0027] The upper first bolt 51 is positioned on the circumference line 91 at a position where its distance from the rear mount fastening position 26LA is the upper first distance L1A. Similarly, the upper second bolt 52 is positioned on the circumference line 91 at a position where its distance from the rear mount fastening position 26LA is the upper first distance L1A, and is positioned circumferentially next to the upper first bolt 51. Therefore, the upper first bolt 51 and the upper second bolt 52 are positioned circumferentially on the outer circumference 42, along the circumference line 91, such that their distance from the rear mount fastening portion 26L is the upper first distance L1A within the axial end face of the outer circumference 42. Furthermore, the upper first bolt 51 and the upper second bolt 52 are positioned symmetrically with respect to the diameter line 92 connecting the rear mount fastening position 26LA and the central axis 90 of the ring gear 41. The circumferential pitch of the upper first bolt 51 and the upper second bolt 52 on the circumference line 91 is the upper second pitch P2A. The upper second pitch P2A is longer than the upper first pitch P1A, which will be explained later.

[0028] Here, the upper first distance L1A and the upper second pitch P2A can be freely set, but for example, the upper second pitch P2A may be set to be the same length as the circumferential pitch P0 (see Figure 3) when eight bolts are evenly distributed circumferentially on the circumference line 91.

[0029] The upper third bolt 53 is positioned on the circumference line 91 at a position where the distance from the rear mount fastening position 26LA is greater than the upper first distance L1A, resulting in an upper second distance L2A. Similarly, the upper fourth bolt 54 is positioned on the circumference line 91 at a position where the distance from the rear mount fastening position 26LA is greater than the upper second distance L2A. The upper third bolt 53 is positioned on the outer circumference 42 so as to be close to the upper first bolt 51. The upper fourth bolt 54 is also positioned on the outer circumference 42 so as to be close to the upper second bolt 52. Furthermore, the upper third bolt 53 and the upper fourth bolt 54 are positioned symmetrically with respect to the diameter line 92 connecting the rear mount fastening position 26LA and the central axis 90 of the ring gear 41.

[0030] Here, the circumferential pitch between the upper third bolt 53 and the upper first bolt 51 on the circumference 91 is the upper first pitch P1A. Also, the circumferential length between the upper fourth bolt 54 and the upper second bolt 52 on the circumference 91 is also the upper first pitch P1A. The upper first pitch P1A may be the minimum length required to tighten the upper third bolt 53 and the upper first bolt 51. For example, as shown in Figure 2, the upper first pitch P1A may be the length obtained by adding the tool gap S to half the diameter of the chuck portion 80 of the tool used to tighten the upper third bolt 53 and half the outer diameter of the head of the adjacent upper first bolt 51.

[0031] Here, the upper first bolt 51 and upper second bolt 52, located near the rear mount fastening position 26LA, form an upper bolt set 55. In addition, the upper third bolt 53 and upper fourth bolt 54, located at a position away from the rear mount fastening position 26LA, form another upper bolt set 56.

[0032] Next, the arrangement of the lower first bolt 61, lower second bolt 62, lower third bolt 63, and lower fourth bolt 64, which are positioned around the front mount fastening portion 25L, will be described. The parts that are the same as those of the upper first bolt 51, upper second bolt 52, upper third bolt 53, and upper fourth bolt 54 described earlier will be briefly explained.

[0033] The lower first bolt 61 and the lower second bolt 62 are arranged side by side on the outer circumference 42 along the circumference 91, similar to the upper first bolt 51 and the upper second bolt 52, such that their distance from the front mount fastening position 25LA is both the lower first distance L1B. Furthermore, the lower first bolt 61 and the lower second bolt 62 are arranged symmetrically with respect to the diameter line 93 connecting the front mount fastening position 25LA and the central axis 90 of the ring gear 41. The circumferential pitch of the lower first bolt 61 and the lower second bolt 62 along the circumference 91 is the lower second pitch P2B, which is the same length as the upper second pitch P2A. The lower second pitch P2B is longer than the lower first pitch P1B, which will be explained later.

[0034] The lower third bolt 63 and the lower fourth bolt 64 are arranged side by side on the outer circumference 42 along the circumference 91, similar to the upper third bolt 53 and the upper fourth bolt 54, such that the distance from the front mount fastening position 25LA is the lower second distance L2B. The lower third bolt 63 is positioned close to the lower first bolt 61, and the lower fourth bolt 64 is positioned close to the lower second bolt 62. Furthermore, the lower third bolt 63 and the lower fourth bolt 64 are positioned symmetrically with respect to the diameter line 93 connecting the front mount fastening position 25LA and the central axis 90 of the ring gear 41.

[0035] Here, the circumferential pitch of the lower third bolt 63 and the lower first bolt 61 on the circumference 91 is the lower first pitch P1B, which is the minimum length required to tighten the lower third bolt 63 and the lower first bolt 61. Similarly, the circumferential pitch of the lower fourth bolt 64 and the lower second bolt 62 on the circumference 91 is also the lower first pitch P1B. The lower first pitch P1B may be the same length as the upper first pitch P1A.

[0036] Here, the lower first bolt 61 and the lower second bolt 62 form a lower bolt assembly 65. Also, the lower third bolt 63 and the lower fourth bolt 64 form another lower bolt assembly 66.

[0037] Therefore, the electric unit 20 has two bolt sets, an upper bolt set 55 and a lower bolt set 65, and two other bolt sets, another upper bolt set 56 and another lower bolt set 66.

[0038] As explained above, the electric unit 20 positions the upper first bolt 51 and the upper second bolt 52 at a position L1A above the rear mount fastening position 26LA. In this way, the electric unit 20 positions the upper first bolt 51 and the upper second bolt 52 symmetrically with respect to the diameter line 92 at a position slightly away from the rear mount fastening position 26LA. Therefore, the fastening load on the upper first bolt 51 and the upper second bolt 52 can be distributed, reducing the fastening load on the upper first bolt 51 and the upper second bolt 52. As a result, the electric unit 20 can bring the fastening load on the upper first bolt 51 and the upper second bolt 52 closer to the fastening load on the adjacent upper third bolt 53 and upper fourth bolt 54, thereby suppressing the uneven distribution of the fastening load on the upper first bolt 51, upper second bolt 52, upper third bolt 53, and upper fourth bolt 54.

[0039] Furthermore, the upper third bolt 53 and upper fourth bolt 54 are positioned in a region where the distance from the rear mount fastening position 26LA is greater than that of the upper first bolt 51 and upper second bolt 52, so as to be close to the upper first bolt 51 and upper second bolt 52. This increases the fastening load of the upper third bolt 53 and upper fourth bolt, while decreasing the fastening load of the upper first bolt 51 and upper second bolt 52. This further reduces the unevenness in the fastening load of the upper first bolt 51, upper second bolt 52, upper third bolt 53 and upper fourth bolt 54.

[0040] Similarly, the electric unit 20 positions the lower first bolt 61 and the lower second bolt 62 at a position L1B below the front mount fastening position 25LA. In this way, the electric unit 20 positions the lower first bolt 61 and the lower second bolt 62 symmetrically with respect to the diameter line 93 at a position slightly away from the front mount fastening position 25LA. Therefore, the fastening load on the lower first bolt 61 and the lower second bolt 62 can be distributed, thereby reducing the fastening load on the lower first bolt 61 and the lower second bolt 62. In addition, the lower third bolt 63 and the lower fourth bolt 64 are positioned close to the lower first bolt 61 and the lower second bolt 62. This increases the fastening load on the lower third bolt 63 and the lower fourth bolt 64, while decreasing the fastening load on the lower first bolt 61 and the lower second bolt 62. As a result, the unevenness in the fastening load of the lower first bolt 61, lower second bolt 62, lower third bolt 63, and lower fourth bolt 64 can be further reduced.

[0041] As a result, in the electric unit 20, as shown in Figure 3, the unevenness of the fastening load of the eight bolts—the upper first bolt 51, upper second bolt 52, upper third bolt 53, upper fourth bolt 54, lower first bolt 61, lower second bolt 62, lower third bolt 63, and lower fourth bolt 64—can be reduced. Furthermore, these eight bolts can be made less likely to loosen. Note that the bolt numbers, upper 1 to upper 4 and lower 1 to lower 4, indicated in Figure 3 refer to the upper first bolt 51 to upper fourth bolt 54 and lower first bolt 61 to lower fourth bolt 64, respectively.

[0042] Next, a conventional electric unit 120 will be described with reference to Figures 3 and 4. The same reference numerals are used for parts identical to those of the electric unit 20 of the embodiment described earlier with reference to Figures 1 to 3, and their descriptions will be omitted. The ring gear 141 of the electric unit 120 is fixed to the casing 121 by eight bolts, the first bolt 151 to the eighth bolt 158, which are located on the outer circumference 142. The first bolt 151 to the eighth bolt 158 ​​are evenly spaced in the circumferential direction. The circumferential pitch of the first bolt 151 to the eighth bolt 158 ​​is pitch P0.

[0043] Here, the eighth bolt 158 ​​is positioned at an upper third distance M1A from the rear mount fastening position 126LA. The circumferential pitch between the eighth bolt 158 ​​and the first bolt 151, and the circumferential pitch between the eighth bolt 158 ​​and the seventh bolt 157 is pitch P0. Similarly, the fourth bolt 154 is positioned at a lower third distance M1B from the front mount fastening position 125LA. The circumferential pitch between the fourth bolt 154 and the fifth bolt 155, and the circumferential pitch between the fourth bolt 154 and the third bolt 153 is pitch P0. Here, both the upper third distance M1A and the lower third distance M1B are shorter than the upper first distance L1A and the lower first distance L1B of the electric unit 20.

[0044] In the conventional electric unit 120, as described above, a large fastening load is applied to the eighth bolt 158, which is located close to the rear mount fastening position 126LA, and to the fourth bolt 154, which is located close to the front mount fastening position 125LA. Conversely, the fastening load on the sixth bolt 156 and the second bolt hole 152, which are located 90° circumferentially away from the eighth bolt 158 ​​or the fourth bolt 154, is reduced.

[0045] As a result, as shown in Figure 4, an imbalance occurs in the fastening load of the first bolt 151 to the eighth bolt 158, making the first bolt 151 to the eighth bolt 158 ​​more prone to loosening.

[0046] In contrast, in the electric unit 20 of the embodiment, as explained earlier, the upper first bolt 51 and upper second bolt 52 are arranged symmetrically with respect to the diameter line 92 at a position slightly away from the rear mount fastening position 26LA, and the lower first bolt 61 and lower second bolt 62 are arranged symmetrically with respect to the diameter line 93 at a position slightly away from the front mount fastening position 25LA. Furthermore, the upper third bolt 53 and upper fourth bolt 54 are positioned close to the upper first bolt 51 and upper second bolt 52, and the lower third bolt 63 and lower fourth bolt 64 are positioned close to the lower first bolt 61 and lower second bolt 62. As a result, the electric unit 20 can reduce the unevenness of the fastening load of the eight bolts: the upper first bolt 51, upper second bolt 52, upper third bolt 53, upper fourth bolt 54, lower first bolt 61, lower second bolt 62, lower third bolt 63, and lower fourth bolt 64. Furthermore, the electric unit 20 makes these eight bolts less likely to loosen.

[0047] In the above explanation, the upper first distance L1A and the lower first distance L1B were described as being set so that the upper second pitch P2A and the lower second pitch P2B are the same length as the circumferential pitch P0 when eight bolts are evenly distributed circumferentially on the circumference line 91, but this is not limited to this. The upper first distance L1A and the lower first distance L1B may be shorter than the pitch P0, as long as the upper second pitch P2A and the lower second pitch P2B are longer than the upper first pitch P1A and the lower first pitch P1B.

[0048] Furthermore, the upper first distance L1A, upper second distance L2A, upper first pitch P1A, and upper second pitch P2A may be the same length as the lower first distance L1B, lower second distance L2B, lower first pitch P1B, and lower second pitch P2B, respectively, or they may be different.

[0049] Furthermore, although the above description assumes that the ring gear 41 of the electric unit 20 is fixed to the casing 21 with eight bolts, it may be fixed to the casing 21 with more than eight bolts. For example, additional bolts may be placed at positions where the distance from the rear mount fastening position 26LA is longer than the upper second distance L2A, or additional bolts may be placed at positions where the distance from the front mount fastening position 25LA is longer than the lower second distance L2B.

[0050] Furthermore, although the above description assumes that the casing 21 is supported by four mounts—left and right front mounts 13L and 13R, and left and right rear mounts 14L and 14R—it is not limited to this, as long as there are two mount fastening positions within the axial end face 45 of the outer circumference 42 of the ring gear 41.

[0051] For example, even if there is one rear mount located in the center in the vehicle width direction and there is only one rear mount fastening portion, there will be two mount fastening positions within the axial end face 45 of the outer circumference 42 of the ring gear 41. Therefore, similar to the electric unit 20, it will be configured to have two sets of bolt sets 55, 65 and two other sets of bolt sets 56, 66. The same applies when there are two rear mounts on the left and right and one front mount located in the center in the vehicle width direction.

[0052] Furthermore, if there are three or more mounts supporting the casing 21 on the left and right sides, and the casing 21 has three or more mount fastening parts and three or more mount fastening positions, the system may be configured to have the same number of bolt sets and multiple other bolt sets.

[0053] Furthermore, although the above description assumes that the lower mount fastening position is located at the front of the vehicle and the upper mount fastening position is located at the rear of the vehicle, this is not limited to the above. If multiple mount fastening positions are provided within the axial end face 45 of the outer circumference 42 of the ring gear 41, then this configuration is possible. For example, the lower mount fastening position may be located at the rear of the vehicle and the upper mount fastening position may be located at the front of the vehicle.

[0054] In the above explanation, the left and right front mounts 13L and 13R were described as being provided on the cross member 12, but they may also be provided on the left and right side members 11L and 11R, similar to the rear mounts 14L and 14R. [Explanation of symbols]

[0055] 10 Body, 11L, 11R Side members, 12 Cross members, 13L, 13R Front mounts, 14L, 14R Rear mounts, 20, 120 Electric units (vehicle electric units), 21, 121 Casing, 23L, 23R Front mount bolts, 24L, 24R Rear mount bolts, 25L, 25R Front mount fastening parts, 25LA, 125LA Front mount fastening positions, 26L, 26R Rear mount fastening parts, 26LA, 126LA Rear mount fastening positions, 27 Gear mounting seat, 28 Screw hole, 30 Motor, 40 Transmission gear, 41, 141 Ring gear, 42, 142 Outer circumference, 43 Teeth, 45 Axial end face, 50 Bolts, 51 Upper first bolt, 52 Upper second bolt, 53 Upper third bolt, 54 Upper 4th bolt, 55 Upper bolt set, 56 Other upper bolt set, 61 Lower 1st bolt, 62 Lower 2nd bolt, 63 Lower 3rd bolt, 64 Lower 4th bolt, 65 Lower bolt set, 66 Other lower bolt set, 80 Chuck section, 90 Central axis, 91 Circumference line, 92, 93 Diameter line, 100 Electric vehicle, L1A Upper 1st distance, L1B Lower 1st distance, L2A Upper 2nd distance, L2B Lower 2nd distance, M1A Upper 3rd distance, M1B Lower 3rd distance, S Tool clearance.

Claims

1. A vehicle electric unit, A motor for driving the vehicle, A speed change gear connected to the motor, The motor and the casing housing the gear change gear are included, The aforementioned gear change gear includes a ring gear having a cylindrical outer circumference and a plurality of teeth protruding radially inward from the outer circumference. The ring gear is fastened to the casing by a plurality of bolts arranged on its outer circumference. The aforementioned multiple bolts are arranged at unequal pitches in the circumferential direction. The casing comprises a plurality of mounting fastening portions that are fastened to a plurality of mounts provided on the body, The aforementioned multiple bolts A plurality of bolt sets, each consisting of a first bolt and a second bolt, are arranged circumferentially on the outer circumference such that the distance from the mounting fastening position within the axial end face of the outer circumference is a first distance, The system includes a plurality of other bolts arranged on the outer periphery such that the distance from the mount fastening position within the axial end face of the outer periphery is greater than the first distance. A vehicle-mounted electric unit characterized by the following.

2. The electric vehicle unit according to claim 1, The aforementioned multiple other bolts are This includes a plurality of other bolt sets, each consisting of a third bolt and a fourth bolt, which are arranged on the outer periphery such that the distance from the mount fastening position within the axial end face of the outer periphery is a second distance that is longer than the first distance. The third bolt is positioned close to the first bolt, and the fourth bolt is positioned close to the second bolt. A vehicle-mounted electric unit characterized by the following.

3. The electric vehicle unit according to claim 2, The circumferential pitch between the first bolt and the third bolt, and the circumferential pitch between the second bolt and the fourth bolt, is a first pitch which is the minimum length required to tighten each bolt, and the circumferential pitch between the first bolt and the second bolt is longer than the first pitch. A vehicle-mounted electric unit characterized by the following.

4. The electric unit according to claim 3, The first bolt and the second bolt, and the third bolt and the fourth bolt are arranged symmetrically within the axial end face of the outer circumference with respect to the diameter line connecting the mount fastening position and the central axis of the ring gear. A vehicle-mounted electric unit characterized by the following.

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