Drive unit
The drive device addresses the challenge of balancing capacity and size in integrated drive units by using a common fastening member to secure the cases, achieving reduced size and enhanced structural integrity with optimized space utilization.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- TOYOTA JIDOSHA KK
- Filing Date
- 2023-06-07
- Publication Date
- 2026-07-22
AI Technical Summary
Existing integrated drive devices for vehicles face challenges in balancing the capacity of the gear case and power conversion unit case while minimizing the overall size, often requiring excessive space for fastening members.
A drive device configuration that uses a common fastening member to secure the first and second cases to the motor case, reducing the total number of fastening members and optimizing the use of space, thereby ensuring case capacity and minimizing the device's size.
This configuration allows for secure fastening of the cases while reducing the size of the drive unit and enhancing the strength of the second flange, effectively utilizing space around the motor shaft, and improving sealing and vibration suppression.
Smart Images
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Abstract
Description
Technical Field
[0001] The technology disclosed in this specification relates to a drive device for a vehicle.
Background Art
[0002] The drive device for a vehicle disclosed in Patent Document 1 has a configuration in which a motor case housing a motor, a gear case housing a gear unit, and a power conversion unit case housing a power conversion unit are integrally fastened.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] In an integrated drive device, it is required to balance ensuring the capacities of the gear case and the power conversion unit case and reducing the size of the drive device.
Means for Solving the Problems
[0005] The drive device for a vehicle disclosed in this specification includes a motor case housing a motor, a first case housing a gear unit mechanically connected to the motor, and a second case housing a power conversion unit electrically connected to the motor. The first case and the second case are fastened to the motor case by a plurality of fastening members. The plurality of fastening members includes at least one common fastening member that co-fastens the first case and the second case to the motor case.
[0006] In configurations that use fastening members to fasten cases together, space is generally required to accommodate the fastening members. As a result, the case capacity may not be sufficient, or the size of the drive unit may become larger. The above configuration includes a common fastening member that fastens the first and second cases together to the motor case. This reduces the total number of fastening members required. Since the total number of fastening members is reduced, the space required to accommodate the fastening members can be reduced. This makes it possible to secure the capacity of the first and second cases while also making the size of the drive unit smaller. [Brief explanation of the drawing]
[0007] [Figure 1] This is a cross-sectional view showing the schematic configuration of the drive unit 1. [Figure 2] This is a perspective view of casing 10. [Figure 3] This is an exploded plan view of the casing 10. [Modes for carrying out the invention]
[0008] At the location of at least one common fastening member, the second case may be positioned on top of the first case.
[0009] With the above configuration, it becomes possible to fasten the first and second cases together to the motor case.
[0010] The first case may include a first flange extending along its outer periphery and fixed to the motor case by a portion of a plurality of fastening members. The second case may include a second flange extending along its outer periphery and fixed to the motor case by a portion of a plurality of fastening members. A portion of the first flange may have an overlapping section located between the motor case and the second flange. At least one common fastening member may include at least one first common fastening member located in the overlapping section.
[0011] According to the above configuration, by using a first common fastening member in the overlapping section between the first flange and the second flange, it becomes possible to reduce the total number of fastening members.
[0012] The first case may further include an extension that extends from one end to the other of the overlapping section along the outer edge of the second case, between the motor case and the second flange. At least one common fastening member may include at least one second common fastening member located in the extension.
[0013] According to the above configuration, the entire outer edge of the second case can be fastened by the first common fastening member and the second common fastening member.
[0014] The average thickness of the second flange may be greater than the average thickness of the first flange.
[0015] Since the fastening member contacts the second flange, a large force is applied to the second flange by the fastening member. With the above configuration, the strength of the second flange can be increased compared to the first flange, making it possible to suppress damage to the second flange.
[0016] The motor may include a motor shaft. At least a portion of the second case may overlap with the first case in a direction perpendicular to the central axis of the motor shaft.
[0017] According to the above configuration, the amount of protrusion of the motor shaft in the central axis direction in the second case can be reduced. This makes it possible to reduce the size of the drive unit.
[0018] In the axial direction of the motor shaft, at least a portion of the second case may overlap with the motor.
[0019] According to the above configuration, the amount of protrusion of the second case in the direction perpendicular to the central axis of the motor shaft can be reduced. This makes it possible to reduce the size of the drive unit.
[0020] When viewed from the central axis direction of the motor shaft, the second case may be arranged along a part of the circumference centered on the motor shaft. The arrangement range of the second case in the rotational direction of the motor may be 180° or more around the motor shaft.
[0021] According to the above configuration, the space around the motor shaft can be effectively utilized.
[0022] The motor may include a motor shaft. Each of the plurality of fastening members may include a bolt. The longitudinal direction of the bolt may be substantially parallel to the central axis of the motor shaft.
[0023] The first case may define a space for accommodating the gear unit between the motor case and the first case.
[0024] The second case may define a space for accommodating the power conversion unit between the motor case and the second case.
Embodiment
[0025] (Configuration of the drive device 1) FIG. 1 is a cross-sectional view showing a schematic configuration of the drive device 1 of the present embodiment. The drive device 1 is an integrated device in which a motor, a gear unit, and a power conversion unit for controlling the motor are housed in the same casing. The directions FR, RH, and UP indicate the direction of the drive device 1 with respect to the vehicle when the drive device 1 is mounted on a vehicle (electric vehicle). The direction FR indicates the front in the longitudinal direction of the vehicle. The direction RH indicates the right side in the left-right direction (or width direction) of the vehicle. The direction UP indicates the upper side in the vertical direction of the vehicle. The same applies to other drawings. In FIG. 1, a plurality of shafts (motor shaft 43, counter shaft 52, drive shafts 57L and 57R) are shown unfolded so as to be located in the same plane.
[0026] The drive unit 1 is controlled by the control unit 2. The control unit 2 includes a CPU, RAM, ROM, input / output interface, etc. The control unit 2 is connected to a power conversion unit 21, etc., by signal lines (not shown).
[0027] The drive unit 1 comprises a casing 10. The casing 10 includes a first case 11, a second case 12, and a motor case 13. The first case 11, the second case 12, and the motor case 13 may be made of cast iron.
[0028] The motor case 13 includes a motor compartment 31. The motor compartment 31 houses the motor 40. In other words, the motor case 13 houses the motor 40. The motor 40 comprises a stator 41, a rotor 42, and a motor shaft 43. The stator 41 has a cylindrical shape. The rotor 42 is rotatably arranged inside the stator 41. The motor shaft 43 has a central axis CA.
[0029] The motor case 13 also has opposing surfaces 13s that face the first case 11 and the second case 12. A motor shaft hole MH and a drive shaft hole DH1 are formed in the opposing surfaces 13s. The motor shaft 43 passes through the motor shaft hole MH. The left drive shaft 57L passes through the drive shaft hole DH1.
[0030] The first case 11 has a box shape with one side open. The first case 11 is fastened to the opposing surface 13s such that the opening surface is closed by the opposing surface 13s. The fastening method will be described later. As a result, a first space SP1 is defined between the motor case 13 and the first case 11. The gear unit 50 is housed in the first space SP1. In other words, the first case 11 houses the gear unit 50.
[0031] The gear unit 50 comprises a shaft gear 51, a countershaft 52, a first counter gear 53, a second counter gear 54, a ring gear 55, and a differential gear 56. The shaft gear 51 is mounted on the motor shaft 43. This mechanically connects the gear unit 50 and the motor 40. The first counter gear 53 and the second counter gear 54 are mounted on the countershaft 52. The first counter gear 53 meshes with the shaft gear 51. The second counter gear 54 meshes with the ring gear 55. The ring gear 55 is mounted on the differential gear 56. A pair of drive shafts 57L and 57R extend from the differential gear 56 in the vehicle width direction. The drive shaft 57R passes through a drive shaft hole DH2 formed in the first case 11. A reservoir 58 is provided at the bottom of the first space SP1. Oil 57 is stored in the reservoir 58. A portion of the gear unit 50 is immersed in oil 57 stored in the reservoir 58.
[0032] The second case 12 has a box shape with one side open. The second case 12 is fastened to the opposing surface 13s such that the opening surface is closed by the opposing surface 13s. The fastening method will be described later. As a result, a second space SP2 is defined between the motor case 13 and the second case 12. The power conversion unit 21 is housed in the second space SP2. In other words, the second case 12 houses the power conversion unit 21. The power conversion unit 21 is a component for controlling the power supplied to the motor 40 and the power generated. Examples of components included in the power conversion unit 21 include inverters and converters. The power conversion unit 21 is electrically connected to the motor 40 by a busbar 22.
[0033] (Configuration of casing 10) Figure 2 shows a perspective view of the casing 10. Figure 3 shows an exploded plan view of the casing 10. Note that Figures 2 and 3 omit descriptions of the various components housed inside the casing 10. Also, in Figure 2, the position of the motor shaft 43 is indicated by a dotted line.
[0034] The first case 11 includes a first flange 11f extending along the outer periphery of the first case 11. In Figure 3, the first flange 11f is formed in overlapping sections OS and SS. The second case 12 includes a second flange 12f extending along the outer periphery of the second case 12. The motor case 13 includes a motor case flange 13f extending along the outer periphery of the motor case 13. The first flange 11f has a plurality of fastening holes 11h. The second flange 12f has a plurality of fastening holes 12h. The motor case flange 13f and the opposing surface 13s have a plurality of fastening holes 13h.
[0035] As shown in Figure 3, a portion of the first flange 11f has an overlapping section OS. The overlapping section OS is the region where the second flange 12f overlaps the first flange 11f. In other words, in the overlapping section OS, the first flange 11f is located between the opposing surface 13s of the motor case 13 and the second flange 12f.
[0036] The first case 11 also includes an extension 14 that extends from end E1 to end E2 of the overlapping section OS. The extension 14 is a frame-shaped member that extends along the outer edge of the second case 12. The extension 14 has the same thickness as the first flange 11f. The extension 14 is formed integrally with the first case 11. Multiple fastening holes 14h are arranged in the extension 14. The first flange 11f and the extension 14, which are located in the overlapping section OS, form a base having a closed ring shape. An opening area OA is formed inside the ring-shaped base. The ring-shaped base is formed so that it overlaps the second flange 12f by one full turn when the second case 12 is assembled. In other words, the ring-shaped base also functions as a spacer ring.
[0037] The first case 11 and the second case 12 are fastened to the motor case 13 by a plurality of bolts 60. The longitudinal direction of the plurality of bolts 60 is approximately parallel to the central axis CA of the motor shaft 43. This will be explained in detail. The plurality of bolts 60 include at least one first common bolt 61 located in the overlapping section OS. In other words, at the location of the first common bolt 61, the second case 12 is positioned on top of the first case 11. In the overlapping section OS, the fastening hole 12h of the second flange 12f, the fastening hole 11h of the first flange 11f, and the fastening hole 13h of the motor case 13 coincide. The first common bolt 61 passes through the fastening holes 12h and 11h and is inserted into the fastening hole 13h. In this way, the first case 11 and the second case 12 are fastened together to the motor case 13.
[0038] Furthermore, the multiple bolts 60 include at least one second common bolt 62 located in the extension section ES where the extension 14 is present. In the extension section ES, the second common bolt 62 passes through the fastening holes 12h and 14h and is inserted into the fastening hole 13h. In this way, the extension 14 and the second case 12 are fastened together to the motor case 13. In other words, the extension 14 is located between the motor case 13 and the second flange 12f.
[0039] In section SS of the first flange 11f, which is a section other than the overlapping section OS, a bolt 60 is placed. In section SS, the bolt 60 passes through the fastening hole 11h and is inserted into the fastening hole 13h (see Figure 2). In this way, the first case 11 is fastened to the motor case 13.
[0040] The average thickness of the second flange 12f is greater than the average thickness of the first flange 11f. The effect is explained below. In the region where the first case 11 and the second case 12 are fastened together to the motor case 13, the bolts come into contact with the second flange 12f. Therefore, the force applied by the bolts is greater on the second flange 12f than on the first flange 11f. By increasing the strength of the second flange 12f above that of the first flange 11f, it is possible to suppress damage to the second flange 12f.
[0041] (Positional relationship between Case 11 and Case 2) As shown in Figure 1, a space is formed on the region opposite the gear unit 50 to the motor shaft 43 due to the dimensional difference between the motor 40 and the gear unit 50. The second case 12 is positioned in this space. That is, in the direction D1 perpendicular to the central axis CA of the motor shaft 43, at least a portion of the second case 12 overlaps with the first case 11. This allows for effective use of the space around the motor shaft 43. Therefore, the amount of protrusion of the second case 12 in the direction D2 of the central axis of the motor shaft 43 can be reduced. This makes it possible to reduce the size of the drive unit 1.
[0042] Furthermore, in the central axis direction D2, at least a portion of the second case 12 overlaps with the motor 40. This also allows for effective use of the space around the motor shaft 43. Therefore, the amount of protrusion of the second case 12 in the direction D1 perpendicular to the central axis CA can be reduced.
[0043] As shown in Figure 2, the second case 12 is positioned along a portion of the circumference of the motor shaft 43 when viewed from the central axis direction D2 of the motor shaft 43. The positioning range of the second case 12 in the direction of motor rotation is 180° or more around the motor shaft 43. This makes it possible to secure sufficient capacity for the second case 12.
[0044] (effect) In configurations where cases are fastened using bolts, it is generally necessary to secure space such as tool clearance around the bolt fastening points. As the number of bolt fastening points increases, the required space increases, which may reduce the capacity of the cases. In the technology described herein, in the overlapping section OS of the first flange 11f and the second flange 12f, the first case 11 and the second case 12 can be fastened together to the motor case 13 using the first common bolt 61. This reduces the total number of bolts required, thereby reducing the space required for the bolts. This allows for securing the capacity of the first case 11 and the second case 12, while also enabling a miniaturization of the drive unit 1.
[0045] If the extension portion 14 is not present, a step equal to the thickness of the first flange 11f will be formed between the overlapping section OS and the extension portion section ES (see Figure 3). This step may make it difficult to ensure a proper seal. In the technology described herein, by providing the extension portion 14, the heights of the overlapping section OS and the extension portion section ES can be made equal. This makes it possible to improve the sealing performance of the second case 12.
[0046] In the technology described herein, a spacer ring can be formed by the first flange 11f and the extension 14. Since the spacer ring can function as a cushion, it is possible to suppress vibrations of the second case 12.
[0047] Although embodiments have been described in detail above, these are merely illustrative and do not limit the scope of the claims. The technologies described in the claims include various modifications and changes to the specific examples illustrated above. The technical elements described in this specification or drawings exhibit technical usefulness individually or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technologies illustrated in this specification or drawings achieve multiple objectives simultaneously, and achieving even one of these objectives constitutes technical usefulness in itself.
[0048] (modified version) The positional relationship between the first case 11 and the second case 12 can vary. For example, the second case 12 may be positioned on top of the first case 11. In this case, a second space SP2 may be defined between the first case 11 and the second case 12. Even in this embodiment, the total number of bolts required can be reduced by providing an overlapping section OS.
[0049] The functions of the first case 11 and the second case 12 may be swapped. That is, the power conversion unit 21 may be housed in the first case 11, and the gear unit 50 may be housed in the second case 12.
[0050] The first case 11 does not necessarily have to include the extension portion 14. Furthermore, the extension portion 14 may be a separate component from the first case 11.
[0051] The vehicles on which the drive system described herein is installed are not limited to electric vehicles. The drive system described herein can be installed in, for example, hybrid vehicles and plug-in hybrid vehicles. In this case, the drive system described herein may house multiple motors or a planetary gear mechanism within the casing. Furthermore, the drive system described herein is also applicable to vehicles that use electric motors for at least part of their propulsion, such as fuel cell vehicles. [Explanation of symbols]
[0052] 1: Drive unit 10: Casing 11: First case 11f: First flange 12: Second case 12f: Second flange 13: Motor case 14: Extension 40: Motor 50: Gear unit 60: Bolt 61: First common bolt 62: Second common bolt
Claims
1. A drive system for a vehicle, A motor case that houses the motor, A first case housing a gear unit mechanically connected to the motor, A second case housing a power conversion unit electrically connected to the motor, Equipped with, The first case and the second case are fastened to the motor case by a plurality of fastening members. The plurality of fastening members include at least one common fastening member that fastens the first case and the second case together to the motor case. At the location of the at least one common fastening member, the second case is positioned on top of the first case. The first case includes a first flange that extends along its outer periphery and is fixed to the motor case by some of the plurality of fastening members, The second case includes a second flange that extends along its outer periphery and is fixed to the motor case by some of the plurality of fastening members. A portion of the first flange has an overlapping section located between the motor case and the second flange. The at least one common fastening member includes at least one first common fastening member located in the overlapping section. Drive unit.
2. The first case further includes an extension that extends from one end to the other of the overlapping section along the outer edge of the second case, between the motor case and the second flange. The drive device according to claim 1, wherein the at least one common fastening member includes at least one second common fastening member located in the extension portion.
3. The drive device according to claim 1, wherein the average thickness of the second flange is greater than the average thickness of the first flange.
4. The motor is equipped with a motor shaft, The drive device according to claim 1, wherein at least a portion of the second case overlaps with the first case in a direction perpendicular to the central axis of the motor shaft.
5. The drive device according to claim 4, wherein at least a portion of the second case overlaps with the motor in the central axis direction of the motor shaft.
6. When viewed from the direction of the central axis of the motor shaft, the second case is arranged along a part of the circumference centered on the motor shaft. The drive device according to claim 5, wherein the arrangement range of the second case in the rotation direction of the motor is 180° or more around the motor shaft.
7. The motor is equipped with a motor shaft, Each of the aforementioned fastening members includes a bolt, The drive device according to claim 1, wherein the longitudinal direction of the bolt is substantially parallel to the central axis of the motor shaft.
8. The drive device according to claim 1, wherein the first case defines a space for housing the gear unit between the motor case and the first case.
9. The drive device according to claim 1, wherein the second case defines a space for housing the power conversion unit between the motor case and the second case.