Drive device

Abstract

To provide a drive device that absorbs assembly errors in multiple directions.SOLUTION: A bus bar (60) of a drive device (30) is made of a flat plate-like member extending in an X-axis direction, and includes: a motor side mounting portion (61) to which an electric motor (40) is attached; an ECU side mounting portion (62) to which an ECU (50) is attached; and a protrusion (63) that includes both sides of the bus bar (60) extending in the X-axis direction and is bent to protrude in a thickness direction of the bus bar (60), between the motor side mounting portion (61) and the ECU side mounting portion (62).SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a drive device. [Background technology]

[0002] Patent Document 1 discloses a technology in which an electric power steering device includes a bus bar that electrically connects an electric motor and a controller, and the bus bar has a structure (laminated structure) in which multiple conductive thin plates are stacked. The laminated structure of the bus bar reduces the bending rigidity in the stacking direction, making it easier to deform. This makes it possible to absorb errors (positional errors, dimensional errors) in the stacking direction of the bus bar. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2008-290675 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, the busbar in Patent Document 1 has low bending rigidity only in one direction, the lamination direction, and therefore can only absorb errors in one direction, the lamination direction, leaving room for improvement in absorbing errors in multiple directions, but this is not fully considered in Patent Document 1.

[0005] An object of one aspect of the present disclosure is to provide a drive device that absorbs assembly errors in multiple directions. [Means for solving the problem]

[0006] In order to solve the above problems, a drive device according to one embodiment of the present disclosure comprises an electric motor, a controller that controls the drive of the electric motor, and a connection portion located between the electric motor and the controller and electrically connecting them to each other, the connection portion being made of a flat plate-like member extending in one direction and having mounting portions at one end and the other end of the one direction to which the electric motor and the controller are attached, respectively, and a protrusion bent between the mounting portions of the electric motor and the controller so as to protrude in the thickness direction of the flat plate-like member, including both sides of the flat plate-like member extending in the one direction. Effect of the Invention

[0007] According to one aspect of the present disclosure, it is possible to provide a drive device that absorbs assembly errors in multiple directions. [Brief description of the drawings]

[0008] [Figure 1] 1 is a schematic cross-sectional view showing a schematic configuration of an electric braking device including a drive device according to an embodiment of the present disclosure. [Diagram 2] FIG. 2 is a schematic diagram illustrating a general configuration of a drive device. [Diagram 3] FIG. 2 is a schematic diagram illustrating a general configuration of a drive device. [Figure 4] FIG. 13 is a perspective view showing a bus bar deformed due to an assembly error. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] An embodiment of the present disclosure will be described in detail below with reference to Figs. 1 to 4. In the following description, coordinate axes such as X-axis, Y-axis, and Z-axis as shown in Fig. 1 and the like are defined. In each drawing, the Y-axis direction is the axial direction of the output shaft 41 of the electric motor 40, the X-axis direction is the direction perpendicular to the Y-axis direction, and the Z-axis direction is the direction perpendicular to the X-axis and Y-axis directions. In Fig. 1 and the like, the positive direction of the X-axis is the direction facing the side where the ECU 50 is located with respect to the electric motor 40, the positive direction of the Y-axis is the direction facing the opposite side to the side where the output shaft 41 of the electric motor 40 is located, and the positive direction of the Z-axis is the direction facing the side where the U-phase connector 42 of the electric motor 40 is located.

[0010] <Electric braking device> An example of an apparatus equipped with the drive device 30 of the present disclosure will be described with reference to Fig. 1. Fig. 1 is a schematic cross-sectional view showing a schematic configuration of an electric braking device 100 equipped with the drive device 30 of the present disclosure. An example of the electric braking device 100 is an electromechanical brake called an EMB (Electro Mechanical Brake).

[0011] The electric braking device 100 has a braking unit 10 and a drive unit 30. The braking unit 10 is a unit that applies a braking force to the wheel by pressing a friction material against a rotating body that rotates together with the wheel. The braking unit 10 has a cylinder 11, a shaft 12, a nut (not shown), and a piston (not shown).

[0012] The cylinder 11 has a cylindrical space formed therein with its axis directed in the Y-axis direction. The shaft 12 is disposed in the cylindrical internal space of the cylinder 11. The shaft 12 rotates by the driving force transmitted thereto from the drive device 30. The brake unit 10 may include a gear unit 20. The gear unit 20 is fixed to the cylinder 11. The gear unit 20 is a unit having a plurality of gears, and may function as a speed reduction mechanism that reduces the speed of the rotational motion transmitted from the electric motor 40. The driving force from the electric motor 40 may be transmitted to the shaft 12 via the gear unit 20.

[0013] A nut having a female thread structure that screws into a male thread structure formed on the outer circumferential surface of shaft 12 is attached to shaft 12. The nut moves linearly in the Y-axis direction as shaft 12 rotates. A piston (not shown) is attached to the nut, and the piston moves linearly in the Y-axis direction in conjunction with the linear movement of the nut. When the piston moves linearly, a friction material that moves in conjunction with the linear movement of the piston presses against a rotating body that rotates with the wheel.

[0014] <Drive unit> A drive device 30 of the present disclosure will be described with reference to Figs. 1 to 3. Figs. 2 and 3 are schematic diagrams for explaining a schematic configuration of the drive device 30. The drive device 30 is a device for driving the brake unit 10. As shown in Fig. 1, the drive device 30 includes an electric motor 40, an ECU (Electronic Control Unit) 50, and a bus bar 60. The electric motor 40 is a power source for the brake unit 10, and is attached to the gear unit 20. An output shaft 41 of the electric motor 40 is connected to a gear of the gear unit 20. An example of the electric motor 40 is a three-phase brushless motor. The electric motor 40 has connectors 42 corresponding to the U phase, W phase, and V phase, respectively. The connectors 42 are arranged on the end side of the electric motor 40 in the positive Y-axis direction, that is, on the opposite side to the side where the output shaft 41 is located in the Y-axis direction.

[0015] The ECU 50 is an electronic control unit that controls the driving of the electric motor 40. The ECU 50 is an example of a controller. The ECU 50 is attached to the outer circumferential surface of the cylinder 11, and is disposed so as to face the electric motor 40 in the X-axis direction. The ECU 50 is configured by a microcomputer having a processor, a memory, and a drive circuit. The ECU 50 is provided with at least one processor, and the processor executes various controls according to a control program stored in the memory. An example of the processor is a CPU (Central Processing Unit). The memory stores various data together with the control program. Examples of the memory are a RAM, a ROM, a flash memory, and the like. The drive circuit includes an inverter, and converts a direct current supplied from a battery or the like into a three-phase alternating current of a U phase, a W phase, and a V phase, and supplies the current to the electric motor 40. The ECU 50 has connectors 51 corresponding to the U phase, the W phase, and the V phase, respectively.

[0016] The bus bar 60 electrically connects the electric motor 40 and the ECU 50. The bus bar 60 is an example of a connection part. The bus bar 60 is a flat metal member extending along the X-axis direction. As shown in FIG. 2, the bus bar 60 is connected to the electric motor 40 and the ECU 50 such that the thickness direction of the bus bar 60 is along the Z-axis direction. That is, the thickness direction of the bus bar 60 is not along the Y-axis direction. The bus bar 60 is inserted into the electric motor 40 from the negative Y-axis direction and attached to the connector 42 of the electric motor 40. The bus bar 60 is also attached to the connector 51 of the ECU 50 from the surface of the ECU 50 facing the electric motor 40, that is, the surface of the ECU 50 on the negative X-direction side.

[0017] In this embodiment, the drive device 30 includes a bus bar 60U corresponding to the U phase, a bus bar 60W corresponding to the W phase, and a bus bar 60V corresponding to the V phase. In this specification, the bus bars 60U, 60W, and 60V are collectively referred to as "bus bars 60". The bus bars 60U, 60W, and 60V are arranged in a line along the Z-axis direction at a predetermined interval. The predetermined interval is an interval at which adjacent bus bars 60 are assumed not to contact each other when the bus bars 60 are bent due to an assembly error. By arranging the multiple bus bars 60 in a line along the Z-axis direction, which is the plate thickness direction of the bus bars 60, it is possible to reduce the arrangement space of the bus bars 60 in the Z-axis direction, particularly the arrangement space of the bus bars 60 between the electric motor 40 and the ECU 50. This makes it easier to arrange signal lines electrically connected between the electric motor 40 and the ECU 50.

[0018] A detailed configuration of busbar 60 will be described below. In Fig. 2, in consideration of ease of viewing the drawing, a reference numeral indicating a detailed configuration is given only to busbar 60V connecting the V phase, and reference numerals indicating a detailed configuration are omitted for busbars 60U and 60W.

[0019] The bus bar 60 has a motor side mounting portion 61, an ECU side mounting portion 62, and a protruding portion 63. The motor side mounting portion 61 is a mounting portion that is attached to the connector 42 of the electric motor 40. That is, the connector 42 of the electric motor 40 is attached to the end of the bus bar 60 in the negative X-axis direction. The motor side mounting portion 61 is a portion that is located inside the electric motor 40 when viewed from the Y-axis direction. The ECU side mounting portion 62 is a mounting portion that is attached to the connector 51 of the ECU 50. That is, the connector 51 of the ECU 50 is attached to the end of the bus bar 60 in the positive X-axis direction. The ECU side mounting portion 62 is a portion that is located inside the ECU 50 when viewed from the Y-axis direction. The protruding portion 63 is located between the electric motor 40 and the ECU 50. That is, the protruding portion 63 is located between the motor side mounting portion 61 and the ECU side mounting portion 62. The protruding portion 63 is a portion located outside the electric motor 40 and the ECU 50 when viewed from the Y-axis direction. The protruding portion 63 is bent so as to include both sides of the bus bar 60 extending in the X-axis direction and protrude in the plate thickness direction of the bus bar 60. Note that it is sufficient that the protruding portion 63 is bent so that a part of the portion located outside the electric motor 40 and the ECU 50 includes both sides of the bus bar 60 and protrudes in the plate thickness direction of the bus bar 60. The protruding portion 63 is bent in a curved arc shape. The bus bar 60 is molded with an insulating resin 65 having electrical insulation properties. More specifically, the protruding portion 63 is molded with the insulating resin 65. The insulating resin 65 is a resin having a deformable softness. Note that it is sufficient that the insulating resin 65 is molded on at least the protruding portion 63, and may be molded on a part of the motor side mounting portion 61 and the ECU side mounting portion 62.

[0020] <About the assembly error between the electric motor and ECU50> Deformation of busbar 60 when an assembly error occurs will be described with reference to Figures 2 to 4. Figure 4 is a perspective view showing busbar 60 deformed due to an assembly error. In Figure 4, non-deformed busbar 60 is represented by a solid line, and deformed busbar 60 is represented by a dashed line or a two-dot chain line. In Figure 4, motor side mounting portion 61 and ECU 50 mounting portion are linear to make the deformation of busbar 60 easy to understand.

[0021] Here, in the present disclosure, an assembly error means a state in which the positional relationship between the electric motor 40 and the ECU 50 set at the time of design is taken as a reference position, and the positional relationship between the electric motor 40 and the ECU 50 when the drive unit 30 is assembled is deviated from the reference position. Assembly errors include deviations (errors) in the mounting positions of the components that constitute the drive unit 30 or the electric braking device 100, or dimensional errors of the components that constitute the drive unit 30. It is considered that assembly errors in multiple directions occur between the electric motor 40 and the ECU 50. The following six patterns of possible assembly errors in multiple directions will be described as examples.

[0022] In the following description, center lines A1 to A5 are defined. Center line A1 is the center line of output shaft 41 of electric motor 40. Center line A2 is a line in the X-axis direction and passes through the center of electric motor 40 in the Z-axis direction. Center line A3 is a line in the Z-axis direction and passes through the center of electric motor 40 in the X-axis direction. Center line A4 is a line in the Z-axis direction and passes through the center of ECU 50 in the X-axis direction. Center line A5 is a line in the Y-axis direction and passes through the center of ECU 50 in the X-axis direction.

[0023] (Pattern 1) Pattern 1 is an assembly error in the X-axis direction between the ECU 50 and the electric motor 40, as indicated by the arrow L1 in Fig. 2. The assembly error indicated by the arrow L1 may be (i) an assembly error in the negative X-axis direction, i.e., a case in which the distance between the center line A3 of the electric motor 40 and the center line A4 of the ECU 50 is shortened, or (ii) an assembly error in the positive X-axis direction, i.e., a case in which the distance between the center line A3 of the electric motor 40 and the center line A5 of the ECU 50 is lengthened. In the assembly error of pattern 1, an error occurs in the distance between the connector 42 of the electric motor 40 and the connector 51 of the ECU 50 in the X-axis direction.

[0024] Reference numeral 301 in Fig. 4 indicates the deformation of busbar 60 when an assembly error occurs in the X-axis direction. When an assembly error occurs in the negative X-axis direction, an external force acts on busbar 60 in a direction that causes busbar 60 to contract, causing protrusion 63 of busbar 60 to bend as shown by the dashed line. When an assembly error occurs in the positive X-axis direction, an external force acts on busbar 60 in a direction that causes busbar 60 to pull, causing protrusion 63 to be stretched as shown by the two-dot chain line. In this way, even if an assembly error occurs in the X-axis direction, the assembly error in the X-axis direction can be absorbed by deformation of protrusion 63.

[0025] (Pattern 2) 2, is an assembly error in the Z-axis direction between the ECU 50 and the electric motor 40. In the assembly error of Pattern 2, an assembly error occurs between the connector 42 of the electric motor 40 and the connector 51 of the ECU 50 in the Z-axis direction.

[0026] Reference numeral 302 in Fig. 4 shows an example of deformation of the busbar 60 when an assembly error occurs in the Z-axis direction. More specifically, reference numeral 302 shows deformation of the busbar 60 when an assembly error occurs in the positive Z-axis direction. As shown by reference numeral 302, when an assembly error occurs in the positive Z-axis direction, an external force that pulls the busbar 60 in the positive Z-axis direction acts on the busbar 60, and the protrusion 63 is pulled as shown by the dashed line. This makes it possible to absorb the assembly error in the positive Z-axis direction.

[0027] (Pattern 3) Pattern 3 is an assembly error in the Y-axis direction between the ECU 50 and the electric motor 40, as indicated by the arrow L3 in Fig. 2. In the assembly error of Pattern 3, an assembly error occurs between the connector 42 of the electric motor 40 and the connector 51 of the ECU 50 in the Y-axis direction.

[0028] Reference numeral 303 in Fig. 4 shows an example of deformation of the busbar 60 when an assembly error occurs in the Y-axis direction. More specifically, reference numeral 303 shows deformation of the busbar 60 when an assembly error occurs in the positive Y-axis direction. As shown by reference numeral 303, when an assembly error occurs in the positive Y-axis direction, an external force that pulls the busbar 60 in the positive Y-axis direction acts on the busbar 60, so that the protrusion 63 is pulled as shown by the dashed line. This makes it possible to absorb the assembly error in the positive Y-axis direction.

[0029] (Pattern 4) Pattern 4 is an assembly error in the rotation direction around the Y-axis. In the assembly error of Pattern 4, an assembly error occurs in the rotation direction between the connector 42 of the electric motor 40 and the connector 51 of the ECU 50 in the rotation direction around the Y-axis. Due to this assembly error in the rotation direction, in the assembly error of Pattern 4, there is a possibility that a position error occurs between the connector 42 of the electric motor 40 and the connector 51 of the ECU 50 in the X-axis direction and the Z-axis direction. An example of the assembly error of Pattern 4 is shown by the arrow R1 in FIG. 3. As shown by the arrow R1, when assembled, an assembly error in the rotation direction around the center line A5 may occur between the ECU 50 and the electric motor 40.

[0030] Reference numeral 304 in Fig. 4 shows an example of deformation of the busbar 60 when an assembly error occurs in the rotation direction around the Y-axis. More specifically, reference numeral 304 shows deformation of the busbar 60 when an assembly error occurs in the counterclockwise rotation direction around the center line A5 shown in Fig. 3 as viewed from the negative Y-axis direction. An external force acts on the busbars 60U and 60W in a direction that contracts the busbars 60U and 60W in the negative X-axis direction, and an external force acts on the busbars 60U and 60W in a direction that pulls the busbars 60U and 60W in the positive Z-axis direction. An external force acts on the busbar 60V in a direction that pulls the busbar 60V in the positive X-axis direction, and an external force acts on the busbar 60V in a direction that pulls the busbar 60V in the positive Z-axis direction. Therefore, as shown by the dashed lines in reference numeral 304, the protruding portions 63 of the busbars 60U and 60W are bent in the X-axis direction, and the protruding portion 63 of the busbar 60V is pulled in the X-axis direction. In addition, bus bar 60 is pulled in the Z-axis direction, which makes it possible to absorb assembly errors in the rotation direction around the Y-axis.

[0031] (Pattern 5) Pattern 5 is an assembly error in the rotation direction around the Z-axis. In the assembly error of pattern 5, an assembly error occurs in the rotation direction between the connector 42 of the electric motor 40 and the connector 51 of the ECU 50 in the rotation direction around the Z-axis. Due to this assembly error in the rotation direction, in the assembly error of pattern 5, a position error may occur in the X-axis direction between the connector 42 of the electric motor 40 and the connector 51 of the ECU 50. An example of the assembly error of pattern 5 is shown by arrow R2 in FIG. 2. As shown by arrow R2, a rotation error may occur around center line A4 between the ECU 50 and the electric motor 40 when assembled.

[0032] Reference numeral 305 in Fig. 4 shows an example of deformation of the busbar 60 when an assembly error occurs in the rotation direction around the Z-axis. More specifically, reference numeral 304 shows deformation of the busbar 60 when an assembly error occurs in the counterclockwise rotation direction around the center line A4 as viewed from the positive Z-axis direction. An external force acts on the end side of the busbar 60 in the positive Y-axis direction in a direction that contracts the busbar 60 in the negative X-axis direction, and an external force acts on the end side of the busbar 60 in the negative Y-axis direction in a direction that pulls the busbar 60 in the positive X-axis direction. Therefore, as shown by the dashed line in reference numeral 305, the protruding portion 63 of the busbar 60 is bent and pulled. This makes it possible to absorb the assembly error in the rotation direction around the Z-axis.

[0033] (Pattern 6) Pattern 6 is an assembly error in the rotation direction around the X-axis. In the assembly error of Pattern 6, an assembly error occurs between the connector 42 of the electric motor 40 and the connector 51 of the ECU 50 in the rotation direction around the X-axis. Due to this assembly error in the rotation direction, in the assembly error of Pattern 6, there is a possibility that a position error occurs between the connector 42 of the electric motor 40 and the connector 51 of the ECU 50 in the Y-axis direction and the Z-axis direction. An example of the assembly error of Pattern 6 is shown by the arrow R3 in FIG. 2. As shown by the arrow R3, when assembled, an assembly error in the rotation direction around the center line A2 may occur between the ECU 50 and the electric motor 40.

[0034] Reference numeral 306 in FIG. 4 shows an example of deformation of the busbar 60 when an assembly error occurs in the rotation direction around the X-axis. More specifically, reference numeral 306 shows deformation of the busbar 60 when an assembly error occurs in the clockwise rotation direction around the center line A2 as viewed from the negative X-axis direction. Since an external force acts on the busbar 60 in a direction rotating around the center line A2, the busbar 60 is twisted around the center line A2 as shown by the dashed line in reference numeral 306. An external force acts on the end of the busbar 60 in the positive Y-axis direction in a direction pulling the busbar 60 in the negative Y-axis direction and the positive Z-axis direction, and an external force acts on the end of the busbar 60 in the negative Y-axis direction in a direction pulling the busbar 60 in the positive Y-axis direction and the negative Z-axis direction. Therefore, as shown by the dashed line in reference numeral 306, the protruding portion 63 of the busbar 60 is pulled. This makes it possible to absorb the assembly error in the rotation direction around the X-axis.

[0035] As described above, the bus bar 60 of the present disclosure has a protruding portion 63 that protrudes in the plate thickness direction of the flat plate member between the motor side mounting portion 61 and the ECU side mounting portion 62 formed at both ends of the flat plate member in one direction. The protruding portion 63 protrudes including both sides extending in one direction. This makes the protruding portion 63 less rigid than the motor side mounting portion 61 and the ECU side mounting portion 62 attached to the electric motor 40 and the ECU 50. Therefore, the protruding portion 63 can be deformed in the direction of an applied external force, and therefore can absorb assembly errors in multiple directions. The bus bar 60 of the present disclosure can also absorb positional deviations between the electric motor 40 and the ECU 50 that occur in multiple directions due to the operation (e.g., vibration, etc.) of the drive device 30.

[0036] Furthermore, by aligning the plate thickness direction of the bus bar 60 in the Z-axis direction, it becomes possible to insert the bus bar 60 into the electric motor 40 from the negative Y-axis direction and attach it to the electric motor 40. This makes it easier to attach the bus bar 60 to the electric motor 40 compared to attaching the bus bar 60 to the electric motor 40 from the X-axis direction. Also, compared to attaching the bus bar 60 to the electric motor 40 from the X-axis direction, it is possible to reduce the risk that the motor side attachment portion 61 will come off the connector 42 due to vibration. Furthermore, by aligning the plate thickness direction of the bus bar 60 in the Z-axis direction, it is not necessary to perform processing or the like to adjust the width of the motor side attachment portion 61 in the Z-axis direction.

[0037] Other embodiments In the above-described embodiment, the plate thickness of the protruding portion 63 of the bus bar 60 may be thinner than the plate thickness of the motor side mounting portion 61 and the plate thickness of the ECU side mounting portion 62. Such a configuration can make the protruding portion 63 more susceptible to deformation due to an assembly error. Note that the plate thickness of the protruding portion 63 may be thicker than the plate thickness of the motor side mounting portion 61 and the plate thickness of the ECU side mounting portion 62, or may be substantially the same as the plate thickness of the motor side mounting portion 61 and the ECU side mounting portion 62.

[0038] In the above-described embodiment, the bus bar 60 has the protruding portion 63, but is not limited to such a configuration. The bus bar 60 may not have the protruding portion 63, and the portion located outside the electric motor 40 and the ECU 50 may be linear.

[0039] In the above-described embodiment, the protruding portion 63 of the busbar 60 is bent in an arc shape, but the present invention is not limited to this configuration. The protruding portion 63 may be bent in a V-shape or a rectangular shape.

[0040] In the above-described embodiment, the bus bar 60 is connected to the electric motor 40 such that the thickness direction of the bus bar 60 is aligned along the Z-axis direction, but the present invention is not limited to this configuration. The thickness direction of the bus bar 60 may be aligned along the Y-axis direction.

[0041] [Additional Notes] The present disclosure is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present disclosure. [Explanation of symbols]

[0042] 10 Braking unit 20 Gear unit 30 Drive unit 40 Electric Motor 41 Output shaft 50 ECU 60 Busbar 61 Motor side mounting part 62 ECU side mounting part 63 Protrusion 65 Insulating resin 100 Electric braking device

Claims

1. An electric motor; A controller for controlling the driving of the electric motor; a connection portion located between the electric motor and the controller to electrically connect them; Equipped with a drive device characterized in that the connection portion is made of a flat plate-like member extending in one direction, and has mounting portions at one end and the other end in the one direction to which the electric motor and the controller are attached, respectively, and a protrusion bent so as to protrude in a thickness direction of the flat plate-like member, including both sides of the flat plate-like member extending in the one direction, between the mounting portions for the electric motor and the controller.

2. 2. The drive device according to claim 1, wherein the protrusion is bent in a curved arc shape.

3. 3. The drive device according to claim 1, wherein a plate thickness of the protruding portion is thinner than a plate thickness of the mounting portion.

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