Motor device

Abstract

A motor device (11) is provided with: a motor (12); a substrate (32) provided at an end of the motor; and a cover (33) attached to the end of the motor so as to cover the substrate. The cover has an end wall facing the substrate in the axial direction of the motor. The end wall includes a first flat wall (33A) and a second flat wall (33B). The first flat wall and the second flat wall each extend in a direction orthogonal to the axial direction of the motor and are disposed adjacent to each other. When viewed from the axial direction of the motor, the area of the first flat wall is larger than that of the second flat wall. The first flat wall is provided with one or more guard ribs (51, 52, 53) protruding to the side opposite to the substrate.

Description

Motor device

[0001] The present disclosure relates to a motor device.

[0002] For example, the motor device of Patent Document 1 includes a motor, an electronic control unit, and a cover. The electronic control unit has a substrate and is attached to the axial end of the motor. The cover is made of metal or resin and covers the electronic control unit.

[0003] Japanese Patent Application Laid-Open No. 2020-4887

[0004] The motor device of Patent Document 1 has the following concerns. For example, when the cover is made of resin, the cover may be damaged if an object hits it. Therefore, it is necessary to appropriately protect the cover.

[0005] The motor device according to one aspect of the present disclosure includes a motor, a substrate provided at an end of the motor, and a cover attached to the end of the motor so as to cover the substrate. The cover has an end wall facing the substrate in the axial direction of the motor. The end wall includes a first flat wall and a second flat wall. The first flat wall and the second flat wall each extend in a direction orthogonal to the axial direction of the motor and are arranged adjacent to each other. When viewed from the axial direction of the motor, the area of the first flat wall is larger than that of the second flat wall. One or more guard ribs protruding to the side opposite to the substrate are provided on the first flat wall.

[0006] Figure 1 is a perspective view showing the external appearance of a motor device according to one embodiment. Figure 2 is an exploded perspective view of the motor device of Figure 1. Figure 3 is a plan view of the cover of Figure 2. Figure 4 is a perspective view of the cover of Figure 2, showing the ribs. Figure 5 is a bottom view of the cover of Figure 2, showing the flow direction of the molten resin during injection molding. Figure 6 is a bottom view of the cover of Figure 2, showing the flow direction of the molten resin during injection molding and the direction in which the ribs extend. Figure 7 is a bottom view of the cover of Figure 2, showing the flow direction of the molten resin during injection molding and the direction in which the ribs extend. Figure 8 is a bottom view showing the main part of the cover of Figure 2. Figure 9 is a plan view of the cover of Figure 2, showing the positioning projection. Figure 10 is a perspective view of the positioning projection of Figure 9. Figure 11 is a side view of the cover of Figure 2, showing the state in which an object such as a flying stone is in contact with the cover. Figure 12 is a cross-sectional view of the main part of the cover assembly equipment shown in Figure 2, showing the cover according to the comparative example in a set state. Figure 13 is a plan view of the main part of the cover assembly equipment shown in Figure 2, showing the cover according to the comparative example in a set state. Figure 14 is a cross-sectional view of the main part of the cover assembly equipment shown in Figure 2, showing the cover according to one embodiment in a set state. Figure 15 is a plan view of the main part of the cover assembly equipment shown in Figure 2, showing the cover according to one embodiment in a set state.

[0007] A motor device 11 according to one embodiment will be described. The motor device 11 is mounted, for example, on the steering system of a vehicle. The steering system includes an electric power steering system and a steer-by-wire steering system.

[0008] <Overall Configuration> As shown in Figure 1, the motor device 11 includes a motor 12 and an electronic control device 13. The motor 12 is, for example, a three-phase brushless motor. The three phases are U-phase, V-phase, and W-phase. The motor 12 has two sets of windings. The electronic control device 13 is provided at the axial end of the motor 12. The electronic control device 13 independently controls the power supply to the two sets of windings.

[0009] <Motor 12> As shown in Figure 2, the motor 12 has a case 12A. The case 12A is a cylindrical metal body with a circular cross-section. Inside the case 12A are a stator, a busbar module, and a rotor. The stator has a core and a plurality of windings. The core is a hollow cylindrical body with a circular cross-section and is fitted to the inner surface of the case 12A. The plurality of windings are wound around the core via an insulator. The busbar module has a holder made of synthetic resin and a plurality of busbars held in the holder. The busbars correspond to each of the three phases. One end of a winding is connected to each busbar. The rotor is inserted into the stator and the busbar module without contact. The rotor has an output shaft 12B and a magnet fixed to the outer surface of the output shaft 12B. The magnet is a cylindrical body with a circular cross-section. The output shaft 12B is rotatably supported by bearings on the inner circumferential surface of the case 12A.

[0010] The motor 12 has a first end on the side from which the output shaft 12B protrudes, and a second end on the opposite side from the first end. The first end of the motor 12 is also the first end of the case 12A, and the second end of the motor 12 is also the second end of the case 12A.

[0011] A substrate housing section 21 is provided at the second end of the motor 12. The substrate housing section 21 is made of metal and is integrally provided with the case 12A. The substrate housing section 21 is a box-shaped body with a rectangular cross-section and has an opening 21A. The opening 21A opens in the direction opposite to the direction in which the output shaft 12B of the motor 12 protrudes. The substrate housing section 21 has a protruding portion 21B. The protruding portion 21B is the part of the substrate housing section 21 that protrudes to the side of the motor 12. The side is perpendicular to the axial direction of the motor 12. The substrate housing section 21 has a fitting hole 21C. The fitting hole 21C is provided in the end wall of the protruding portion 21B. The end wall of the protruding portion 21B is also the end wall of the substrate housing section 21. The fitting hole 21C penetrates the end wall of the protruding portion 21B in the axial direction of the motor 12. The shape of the fitting hole 21C is, for example, a rectangle extending tangentially to the case 12A when viewed from the axial direction of the motor 12. The four corners of the rectangle may be rounded.

[0012] A heat sink 22 is provided at the second end of the motor 12. The heat sink 22 is a cylindrical body with a circular cross-section and is made of a metal with excellent thermal conductivity, such as aluminum. The second end of the case 12A is open, and a part of the heat sink 22 is fitted into the second end of the case 12A. The heat sink 22 has a first end that is fitted into the second end of the case 12A, and a second end that penetrates the end wall of the substrate housing 21 in the axial direction of the motor 12 and is exposed inside the substrate housing 21. The heat sink 22 also functions as a bearing holder. The bearing holder is a member that holds a bearing that rotatably supports the output shaft 12B.

[0013] The heat sink 22 is provided with three first motor terminals 23A. The three first motor terminals 23A correspond to the three phase windings that constitute the first winding group. Each of the first motor terminals 23A is part of a busbar. Inside the case 12A, one end of the first winding of each phase is connected to the busbar of the corresponding phase. The first motor terminals 23A penetrate the heat sink 22 in the axial direction of the motor 12 via an insulating member. The three first motor terminals 23A are arranged in a line tangentially to the contour of the motor 12 when viewed from the axial direction of the motor 12.

[0014] The heat sink 22 is provided with three second motor terminals 23B. The three second motor terminals 24A correspond to the three phase windings that constitute the second winding group. Each of the second motor terminals 23B is part of a busbar. Inside the case 12A, one end of the second winding of each phase is connected to the busbar of the corresponding phase. The second motor terminals 23B penetrate the heat sink 22 in the axial direction of the motor 12 via an insulating member. The three second motor terminals 23B are arranged in a line tangentially to the contour of the motor 12 when viewed from the axial direction of the motor 12.

[0015] The ends of the heat sink 22, from which the first motor terminal 23A and the second motor terminal 23B protrude, are exposed inside the substrate housing 21. <Electronic control unit 13> As shown in Figure 2, the electronic control unit 13 includes a connector assembly 31, a substrate 32, and a cover 33.

[0016] The connector assembly 31 has a body 41 made of synthetic resin. The body 41 includes a base 41A, a first power connector 41B, a second power connector 41C, a first signal connector 41D, and a second signal connector 41E.

[0017] The base 41A is, for example, a box-shaped body having a rectangular cross-section, and opening in the same direction as the opening 21A of the substrate housing 21. The rectangle includes a rectangle or a trapezoid. The base 41A has a first end face facing the opposite direction from the opening 21A of the substrate housing 21, and a second end face facing the opposite side of the first end face, i.e., the same direction as the opening 21A of the substrate housing 21. The direction opposite to the opening 21A of the substrate housing 21 is downward in Figure 2. The direction in the same direction as the opening 21A of the substrate housing 21 is upward in Figure 2. The first end face of the base 41A is also the first end face of the body 41, and the second end face of the base 41A is also the second end face of the body 41.

[0018] The first power connector 41B is provided on the first end face of the base 41A. The first power connector 41B is a cylindrical body that extends from the first end face of the base 41A in the axial direction of the motor 12. The first power connector 41B is open in the direction that the first end face of the base 41A faces. The first power connector 41B is a so-called male connector.

[0019] The first power connector 41B is mated with the first mating connector, which is a so-called female connector. The first power connector 41B is mated inside the first mating connector. The first mating connector is connected via first wiring to a DC power source such as a battery located outside the motor device 11. The first power connector 41B is a first power connector for supplying power from the DC power source to the circuit board 32.

[0020] The second power connector 41C is provided on the first end face of the base 41A. The second power connector 41C is a so-called male connector having the same configuration as the first power connector 41B. The first power connector 41B and the second power connector 41C are spaced apart in the direction of the long side of the base 41A. The direction of the long side is the direction in which the length of the side of the base 41A is longer.

[0021] The second power connector 41C is mated with a second mating connector, which is a so-called female connector. The second power connector 41C is mated inside the second mating connector. The second mating connector is connected via second wiring to a DC power source, such as a battery, located outside the motor device 11. The second power connector 41C is a second power connector for supplying power from the DC power source to the circuit board 32.

[0022] The first signal connector 41D is provided on the first end face of the base 41A. The first signal connector 41D is positioned between the first power connector 41B and the second power connector 41C in the long-side direction of the base 41A. The first signal connector 41D is a cylindrical body that extends from the first end face of the base 41A in the axial direction of the motor 12. The first signal connector 41D opens in the direction that the first end face of the base 41A faces. The third connector 41C is a so-called male connector.

[0023] The first signal connector 41D is mated with a third mating connector, which is a so-called female connector. The first signal connector 41D is mated inside the third mating connector. The third mating connector is connected via a third wiring to a vehicle control device located outside the motor device 11. The first signal connector 41D is a first signal connector for sending and receiving signals between the circuit board 32 and the vehicle control device.

[0024] The second signal connector 41E is provided on the first end face of the base 41A. The second signal connector 41E is a so-called male connector having the same configuration as the first signal connector 41D. The second signal connector 41E is positioned between the second power connector 41C and the first signal connector 41D in the long side direction of the base 41A.

[0025] The second signal connector 41E is mated with its mating partner, the fourth mating connector. The fourth mating connector is a so-called female connector. The second signal connector 41E is mated inside the fourth mating connector. The fourth mating connector is connected via a fourth wiring to a vehicle control device located outside the motor device 11. The second signal connector 41E is a second signal connector for sending and receiving signals between the circuit board 32 and the vehicle control device.

[0026] The connector assembly 31 has a first power terminal 42 and a first ground terminal 43. The first power terminal 42 is provided along a path that extends from inside the first power connector 41B and penetrates the base 41A in the axial direction of the motor 12. The first end of the first power terminal 42 is located inside the first power connector 41B. The second end of the first power terminal 42 is upright with respect to the second end face of the base 41A. The first ground terminal 43 is provided in the same manner as the first power terminal 42. The first power terminal 42 and the first ground terminal 42 are spaced apart in the long side direction of the base 41A.

[0027] The connector assembly 31 has a second power terminal 44 and a second ground terminal 45. The second power terminal 44 is provided along a path that extends from inside the second power connector 41C and penetrates the base 41A in the axial direction of the motor 12. The first end of the second power terminal 44 is located inside the second power connector 41C. The second end of the second power terminal 44 is upright with respect to the second end face of the base 41A. The second ground terminal 45 is provided in the same manner as the second power terminal 44. The second power terminal 44 and the second ground terminal 45 are spaced apart in the long side direction of the base 41A.

[0028] The connector assembly 31 has a plurality of first signal terminals 46. The first signal terminals 46 are provided along a path that extends from inside the first signal connector 41D and penetrates the base 41A in the axial direction of the motor 12. The first end of the first signal terminal 46 is located inside the first signal connector 41D. The second end of the first signal terminal 46 is upright relative to the second end face of the base 41A. The plurality of first signal terminals 46 are arranged at intervals along the long side of the base 41A.

[0029] The connector assembly 31 has a plurality of second signal terminals 47. The second signal terminals 47 are provided along a path that extends from inside the second signal connector 41E and penetrates the base 41A in the axial direction of the motor 12. The first end of the second signal terminal 47 is located inside the second signal connector 41E. The second end of the second signal terminal 47 is upright with respect to the second end face of the base 41A. The plurality of second signal terminals 47 are arranged at intervals along the long side of the base 41A.

[0030] The connector assembly 31 is a resin molded product. The connector assembly 31 is manufactured, for example, by insert molding. Insert molding is a molding technique in which a portion of each terminal (42-47), which is an insert product, is placed in an open mold, and then the mold is closed and injection molding is performed. Inside the mold, a portion of each terminal is encased in molten resin injected into the mold. As this molten resin cools and solidifies, a body 41 is formed on the outer circumference of a specific portion of each terminal (42-47).

[0031] The connector assembly 31 is attached to the substrate housing 21 of the motor 12. The first power connector 41B, the second power connector 41C, the first signal connector 41D, and the second signal connector 41E are inserted into the fitting holes 21C through the opening 21A of the substrate housing 21. The outer circumferential surface of the base 41A is fitted to the inner circumferential surface of the fitting holes 21C of the substrate housing 21. A flange portion 41F is provided around the entire circumference of the outer circumferential surface of the base 41A. The flange portion 41F is maintained in contact with the peripheral portion of the fitting holes 21C of the end wall of the protruding portion 21B in the axial direction of the motor 12. The first power connector 41B, the second power connector 41C, the first signal connector 41D, and the second signal connector 41E protrude from the end wall of the protruding portion 21B in the direction opposite to the opening 21A of the substrate housing 21.

[0032] The circuit board 32 is housed inside the circuit board housing 21. The outer contour shape of the circuit board 32 corresponds to the inner contour shape of the circuit board housing 21 when viewed from the axial direction of the motor 12. The circuit board 32 is positioned overlapping the end of the heat sink 22 exposed inside the circuit board housing 21 and the end of the connector assembly 31 exposed inside the circuit board housing 21. The circuit board 32 is fixed, for example, by screws to a support provided on the body 41 and a support provided inside the circuit board housing 21. The screws pass through the circuit board 32 and are tightened into the support. The circuit board 32 is maintained in a position perpendicular to the axial direction of the motor 12.

[0033] The second end of the first power terminal 42 is inserted into the corresponding first power terminal hole of the substrate 32. The second end of the first ground terminal 43 is inserted into the corresponding first ground terminal hole of the substrate 32. Both the first power terminal hole and the first ground terminal hole are through holes that penetrate the substrate 32 in the thickness direction. The first power terminal hole constitutes the first power terminal connection portion. The first power terminal connection portion is the part of the substrate 32 to which the first power terminal 42 is connected.

[0034] The second end of the second power terminal 44 is inserted into the corresponding second power terminal hole of the circuit board 32. The second end of the second ground terminal 45 is inserted into the corresponding second ground terminal hole of the circuit board 32. Both the second power terminal hole and the second ground terminal hole are through holes that penetrate the circuit board 32 in the thickness direction. The second power terminal hole constitutes the second power terminal connection section. The second power terminal connection section is the portion of the circuit board 32 to which the second power terminal 44 is connected.

[0035] Multiple first signal terminals 46 are each inserted into corresponding first signal terminal holes in the substrate 32. Multiple second signal terminals 47 are each inserted into corresponding second signal terminal holes in the substrate 32. Both the first and second signal terminal holes are through holes that penetrate the substrate 32 in the thickness direction. The first signal terminal holes constitute the first signal terminal connection section. The first signal terminal connection section is the portion of the substrate 32 to which the first signal terminals 46 are connected. The second signal terminal holes constitute the second signal terminal connection section. The second signal terminal connection section is the portion of the substrate 32 to which the second signal terminals 47 are connected.

[0036] Multiple first motor terminals 23A are each inserted into corresponding first motor terminal holes in the substrate 32. Multiple second motor terminals 23B are each inserted into corresponding second motor terminal holes in the substrate 32. Both the first motor terminal holes and the second motor terminal holes are through holes that penetrate the substrate 32 in the thickness direction. The first motor terminal holes constitute the first motor terminal connection portion. The first motor terminal connection portion is the part of the substrate 32 to which the first motor terminals 23A are connected. The second motor terminal holes constitute the second motor terminal connection portion. The second motor terminal connection portion is the part of the substrate 32 to which the second motor terminals 23B are connected.

[0037] The circuit board 32 has an electrical circuit for supplying power to two winding groups of the motor 12. The electrical circuit includes, for example, two inverter circuits and two microcomputers. The first inverter circuit converts DC power from a DC power source into three-phase AC power to generate power to supply to the first winding group. The second inverter circuit converts DC power from a DC power source into three-phase AC power to generate power to supply to the second winding group. The microcomputers are, for example, chip-type integrated circuits. The first microcomputer controls the power supply to the first winding group via the first inverter circuit. The second microcomputer controls the power supply to the second winding group via the second inverter circuit.

[0038] The cover 33 is made of synthetic resin and is a resin molded product manufactured, for example, by injection molding. Injection molding is a molding technique that obtains a resin molded product by injecting molten resin into a mold and cooling and solidifying the molten resin. The cover 33 is a box-shaped body with a rectangular cross-section. The cover 33 is open toward the motor 12. The cover 33 is attached to the substrate housing 21 so as to cover the opening 21 of the substrate housing 21 when the connector assembly 31 and the substrate 32 are attached to it.

[0039] <Configuration of Cover 33> Next, the configuration of the cover 33 will be described in detail. As shown in Figure 2, the cover 33 has a first planar wall 33A and a second planar wall 33B. The first planar wall 33A and the second planar wall 33B are portions of the end wall of the cover 33 that extend in a direction perpendicular to the axial direction of the motor 12. The first planar wall 33A and the second planar wall 33B are arranged side by side in the direction of the long side of the cover 33. In the direction of the long side of the cover 33, the length of the first planar wall 33A is longer than the length of the second planar wall 33B. In the direction of the short side of the cover 33, the first planar wall 33A and the second planar wall 33B are the same length. That is, when viewed from the axial direction of the motor 12, the area of ​​the first planar wall 33A is larger than the area of ​​the second planar wall 33B. Viewed from the axial direction of the motor 12, the area of ​​the second planar wall 33B is smaller than the area of ​​the first planar wall 33A.

[0040] A step exists between the first planar wall 33A and the second planar wall 33B. The step is the difference in height in the axial direction of the motor 12, with respect to the opening end of the cover 33. The first planar wall 33A is positioned higher than the second planar wall 33B relative to the opening end of the cover 33. That is, in the axial direction of the motor 12, the first planar wall 33A is further from the substrate 32 than the second planar wall 33B. The first planar wall 33A and the second planar wall 33B are continuous via an inclined portion 33C. When the cover 33 is attached to the substrate housing 21, in the axial direction of the motor 12, the first planar wall 33A faces the heat sink 22 via the substrate 32, and the second planar wall 33B faces the connector assembly 31 via the substrate 32.

[0041] <Protective Structure of Cover 33> As shown in Figure 3, the cover 33 has a protective structure. The protective structure is designed to protect the cover 33 from collisions with objects such as flying stones. The protective structure includes, for example, first to third guard ribs 51 to 53. The first to third guard ribs 51 to 53 are provided on the surface of the first planar wall 33A. The surface is the face of the first planar wall 33A opposite to the substrate 32 in the axial direction of the motor 12. The first to third guard ribs 51 to 53 are, for example, columnar bodies having a semicircular cross-sectional shape and extending in the direction of the long side of the cover 33.

[0042] The length of the first guard rib 51 in the long-side direction of the cover 33 is longer than the lengths of the second guard rib 52 and the third guard rib 53 in the long-side direction of the cover 33. The second guard rib 52 and the third guard rib 53 in the long-side direction of the cover 33 are the same length. The first to third guard ribs 51 to 53 have the same width. The width is the length of the first to third guard ribs 51 to 53 in the short-side direction of the cover 33. The lengths of the first to third guard ribs 51 to 53 in the long-side direction of the cover 33 are determined by considering, for example, the size of the object that is expected to collide with the cover.

[0043] The first to third guard ribs 51 to 53 are arranged at intervals in the short side direction of the cover 33. The first guard rib 51 is arranged at the center in the short side direction of the cover 33. The first guard rib 51 is provided at a position including the center of the first flat wall 33A when viewed from the axial direction of the motor 12. The second guard rib 52 and the third guard rib 53 are arranged on opposite sides of the first guard rib 51 in the short side direction of the cover 33. The intervals between the first to third guard ribs 51 to 53 in the short side direction of the cover 33 are determined in consideration of, for example, the size of an object for which a collision is predicted.

[0044] The first guard rib 51 has a gate trace PG. The gate trace PG is arranged, for example, at the center in the extending direction of the first guard rib 51. The gate trace GP corresponds to the center of the first flat wall 33A when viewed from the axial direction of the motor 12.

[0045] When the cover 33 is manufactured by injection molding, molten resin is filled into the product cavity through the gate of the mold. The gate is one of the passages for the molten resin provided in the mold and is an entrance through which the molten resin is poured into the product cavity from the injection molding machine. The product cavity is a closed space corresponding to the shape of the cover 33 as a product. After filling the molten resin into the product cavity, the cover 33 is manufactured by cooling and solidifying it. However, a portion corresponding to the passage of the molten resin including the gate remains in the cover 33. The portion corresponding to the passage of the molten resin including the gate is cut because it is unnecessary as a product. The gate trace PG is a trace remaining after cutting the portion corresponding to the passage of the molten resin including the gate.

[0046] <Reinforcement Structure of Cover 33>As shown in FIG. 4, the cover 33 has a first reinforcement structure 60 and a second reinforcement structure 70. The first reinforcement structure 60 and the second reinforcement structure 70 are structures for reinforcing the cover 33. The first reinforcement structure 60 is provided on the back surface of the first planar wall 33A. The back surface is the surface on the opposite side of the front surface, and is the surface of the first planar wall 33A facing the substrate 32 in the axial direction of the motor 12. The first reinforcement structure 50 particularly reinforces the first planar wall 33A. The second reinforcement structure 70 is provided on the back surface of the second planar wall 33B. The back surface is the surface on the opposite side of the front surface, and is the surface of the second planar wall 33B facing the substrate 32 in the axial direction of the motor 12. The second reinforcement structure 70 particularly reinforces the second planar wall 33B. The first reinforcement structure 60 and the second reinforcement structure 70 are each configured by combining a plurality of ribs. A rib is a wall that extends continuously in a specific direction.

[0047] As shown in FIG. 5, the first reinforcement structure 60 has a plurality of first reinforcement ribs 61, a plurality of second reinforcement ribs 62, and a plurality of third reinforcement ribs 63. The plurality of first reinforcement ribs 61 and the plurality of second reinforcement ribs 62 are combined in a grid pattern. That is, the plurality of first reinforcement ribs 61 and the plurality of second reinforcement ribs 62 are combined so as to be orthogonal to each other.

[0048] The first reinforcement ribs 61 extend in the long side direction of the cover 33. The plurality of first reinforcement ribs 61 are arranged at equal intervals in the short side direction of the cover 33. The second reinforcement ribs 62 extend in the short side direction of the cover 33. The plurality of second reinforcement ribs 62 are arranged at equal intervals in the long side direction of the cover 33. The interval between two adjacent second reinforcement ribs 62 in the long side direction of the cover 33 is the same as the interval between two adjacent first reinforcement ribs 61 in the short side direction of the cover 33.

[0049] Multiple third reinforcing ribs 63 are combined to form three concentric figures centered on the gate trace PG when viewed from a direction perpendicular to the end wall of the cover 33. The concentric figures are, for example, quadrilaterals, including squares. Four third reinforcing ribs 63 are combined to form one quadrilateral. The three quadrilaterals are similar to each other. Each of the three quadrilaterals has four vertices. Two of the four vertices face the direction of the long side of the cover 33, and the remaining two face the direction of the short side of the cover 33. The third reinforcing ribs 63 extend so as to pass through the intersection of the first reinforcing ribs 61 and the second reinforcing ribs 62 when viewed from a direction perpendicular to the end wall of the cover 33. That is, the third reinforcing ribs 63 extend so as to diagonally cross the multiple quadrilaterals formed by the first reinforcing ribs 61 and the second reinforcing ribs 62 when viewed from a direction perpendicular to the end wall of the cover 33. The third reinforcing rib 63 is inclined with respect to the first reinforcing rib 61 and the second reinforcing rib 62, respectively. The direction perpendicular to the end wall of the cover 33 is also the axial direction of the motor 12.

[0050] The second reinforcing structure 70 has a plurality of fourth reinforcing ribs 71 and a plurality of fifth reinforcing ribs 72. The plurality of fourth reinforcing ribs 71 and the plurality of fifth reinforcing ribs 72 are arranged in a grid pattern. That is, the plurality of fourth reinforcing ribs 71 and the plurality of fifth reinforcing ribs 72 are arranged so as to be orthogonal to each other.

[0051] The fourth reinforcing rib 71 extends along the long side of the cover 33. Multiple fourth reinforcing ribs 71 are arranged at equal intervals along the short side of the cover 33. The distance between two adjacent fourth reinforcing ribs 71 along the short side of the cover 33 is wider than the distance between two adjacent first reinforcing ribs 61 along the short side of the cover 33.

[0052] The fifth reinforcing rib 72 extends in the direction of the short side of the cover 33. Multiple fifth reinforcing ribs 72 are arranged at equal intervals in the direction of the long side of the cover 33. The distance between two adjacent fifth reinforcing ribs 72 in the direction of the long side of the cover 33 is wider than the distance between two adjacent second reinforcing ribs 62 in the direction of the long side of the cover 33. However, the distance between two adjacent fifth reinforcing ribs 72 in the direction of the long side of the cover 33 is the same as the distance between two adjacent fourth reinforcing ribs 71 in the direction of the short side of the cover 33.

[0053] <Flow Direction of Molten Resin> When the cover 33 is manufactured by injection molding, molten resin is filled into the product cavity through the mold gate. As shown in Figure 5, when viewed from a direction perpendicular to the end wall of the cover 33, the gate mark PG corresponds to the position of the gate. The molten resin flowing into the product cavity from the gate spreads radially from the gate into the product cavity when viewed from a direction perpendicular to the end wall of the cover 33. That is, when viewed from a direction perpendicular to the end wall of the cover 33, the molten resin spreads in all directions within the product cavity with the gate as the center. For the sake of explanation, Figure 5 shows the eight flow directions of the molten resin superimposed on the cover 33, with the gate as the reference point.

[0054] The first flow direction D1 is the 12 o'clock direction. The second flow direction D2 is the 1:30 direction. The 1:30 direction is the direction between the 1 o'clock and 2 o'clock directions. The third flow direction D3 is the 3 o'clock direction. The fourth flow direction D4 is the 4:30 direction. The 4:30 direction is the direction between the 4 o'clock and 5 o'clock directions. The fifth flow direction D5 is the 6 o'clock direction, which is the opposite direction to the first flow direction D1. The sixth flow direction D6 is the 7:30 direction, which is the opposite direction to the second flow direction D2. The 7:30 direction is the direction between the 7 o'clock and 8 o'clock directions. The seventh flow direction D7 is the 9 o'clock direction, which is the opposite direction to the third flow direction D3. The eighth flow direction D8 is the 10:30 direction, which is the opposite direction to the fourth flow direction D3. The 10:30 direction is the direction between the 10 o'clock and 11 o'clock directions.

[0055] The first to third reinforcing ribs 61 to 63 extend in a direction perpendicular to the flow direction of the molten resin during injection molding, when viewed from a direction perpendicular to the end wall of the cover 33. As shown in Figure 6, when viewed from a direction perpendicular to the end wall of the cover 33, two of the four third reinforcing ribs 63 that form a single rectangle extend in a direction perpendicular to the second flow direction D2 and the sixth flow direction D6. The remaining two of the four third reinforcing ribs 63 extend in a direction perpendicular to the fourth flow direction D4 and the eighth flow direction D8. In Figure 6, for the sake of explanation, numerous dots are attached to the third reinforcing ribs 63 that form three rectangles.

[0056] As shown in Figure 7, the first reinforcing rib 61 extends in a direction perpendicular to the third flow direction D3 and the seventh flow direction D7 when viewed from a direction perpendicular to the end wall of the cover 33. The second reinforcing rib 62 extends in a direction perpendicular to the first flow direction D1 and the fifth flow direction D5 when viewed from a direction perpendicular to the end wall of the cover 33. In Figure 7, for the sake of explanation, numerous dots are placed on the portions of the first reinforcing rib 61 and the second reinforcing rib 62 that form four rectangles centered on the gate trace PG.

[0057] As shown in Figure 8, the first to third reinforcing ribs 61 to 63 are also provided in the area on the back of the first planar wall 33A that corresponds to the first to third guard ribs 51 to 53. However, the third reinforcing rib 63 is provided only in the area on the back of the first planar wall 33A that corresponds to the first to third guard ribs 51 to 53. That is, the third reinforcing rib 63 is not provided in the area on the back of the first planar wall 33A that does not correspond to the first to third guard ribs 51 to 53. In Figure 8, for the sake of explanation, numerous dots are placed on the parts of the first to third reinforcing ribs 61 to 63 that correspond to the first to third guard ribs 51 to 53.

[0058] <Positioning Protrusions> As shown in Figures 9 and 10, the cover 33 has a plurality of positioning protrusions 91. The number of positioning protrusions 91 is, for example, six. The positioning protrusions 91 are, for example, columnar bodies having a rectangular cross-sectional shape and are provided on the outer circumferential surface of the cover 33. Two positioning protrusions 91 are provided on each of the two side walls extending in the direction of the long side of the cover 33. The two positioning protrusions 91 are spaced apart in the direction of the long side of the cover 33. One positioning protrusion 91 is provided on each of the two side walls extending in the direction of the short side of the cover 33. The positioning protrusions 91 are located in the center of the cover 33 in the direction of the short side.

[0059] <Operation of this Embodiment> Next, the operation of this embodiment will be described. The motor device 11 is mounted on a vehicle, for example. In this case, as shown in Figure 11, there is a risk that an object 100, such as a flying stone, may collide with the cover 33. The direction from which the object 100 is flying is, for example, the axial direction of the motor 12. The axial direction of the motor 12 is also the direction perpendicular to the end wall of the cover 33. However, the cover 33 has first to third guard ribs 51 to 53. Therefore, when an object 100 collides with the cover 33, there is a high probability that the object 100 will collide with at least one of the first to third guard ribs 51 to 53 before colliding with the surface of the cover 33 other than the first to third guard ribs 51 to 53. In other words, the portion of the cover 33 that the object 100 collides with is narrowed down to the first to third guard ribs 51 to 53. Depending on the size of object 100, object 100 may first collide with the first guard rib 51 and the second guard rib 52, or with the first guard rib 51 and the third guard rib 53. In other words, the impact generated by the collision of object 100 is absorbed by at least one of the first to third guard ribs 51 to 53. Therefore, the cover 33 is protected from the collision of object 100.

[0060] In particular, the first to third guard ribs 51 to 53 are provided on the surface of the first planar wall 33A of the cover 33. The area of ​​the first planar wall 33A is larger than the area of ​​the second planar wall 33B. Therefore, the bending stiffness of the first planar wall 33A is lower than that of the second planar wall 33B. Bending stiffness is an indicator of the resistance force to bending deformation of the first planar wall 33A and the second planar wall 33B in the axial direction of the motor 12. By providing the first to third guard ribs 51 to 53 on the surface of the first planar wall 33A, which is one of the weakest parts of the cover 33, the cover 33 can be effectively protected from collision with the object 100. The first to third guard ribs 51 to 53 are columnar bodies each having a semicircular cross-sectional shape. Therefore, regardless of the angle at which object 100 collides with the first to third guard ribs 51 to 53, the impact of object 100 colliding with the first to third guard ribs 51 to 53 is easily absorbed. This makes it possible to suppress damage to the first planar wall 33A, and consequently the cover 33, caused by collision with object 100. Since damage to the cover 33 caused by collision with object 100 is suppressed, the reliability of the cover 33, and consequently the motor device 11, can be ensured.

[0061] The cover 33 has a first reinforcing structure 60 and a second reinforcing structure 70. This improves the strength of the cover 33. In particular, the first planar wall 33A, which is one of the weakest parts of the cover 33, has the first reinforcing structure 60. The first reinforcing structure 60 has a plurality of first to third reinforcing ribs 61 to 63, and the plurality of first to third reinforcing ribs 61 to 63 extend in a direction intersecting the flow direction of the molten resin during injection molding when viewed from a direction perpendicular to the end wall of the cover 33. Resin molded products including the cover 33 have low strength in the direction perpendicular to the flow direction of the molten resin. This is due to the directionality of the flow of the molten resin. By providing the first planar wall 33A with a plurality of first to third reinforcing ribs 61 to 63 extending in a direction perpendicular to the flow direction of the molten resin, the part of the cover 33 that is weak due to the directionality of the flow of the molten resin is reinforced. Therefore, the strength of the first planar wall 33A, and consequently the cover 33, can be effectively ensured.

[0062] However, the third reinforcing rib 63 is provided only in the area of ​​the back surface of the first planar wall 33A that corresponds to the first to third guard ribs 51 to 53. This is because the portion of the cover 33 that the object 100 collides with is concentrated around the first to third guard ribs 51 to 53. When colliding with the object 100, the portion of the cover 33 that has the first to third guard ribs 51 to 53 is likely to receive a greater impact than other portions of the cover 33 that do not have the first to third guard ribs 51 to 53. For this reason, the third reinforcing rib 63 is provided in the area of ​​the back surface of the first planar wall 33A that corresponds to the first to third guard ribs 51 to 53, in addition to the first and second reinforcing ribs 61 and 62. The third reinforcing rib 63 is not unnecessarily provided in the area of ​​the back surface of the cover 33 that does not correspond to the first to third guard ribs 51 to 53. Therefore, the cover 33 can be effectively reinforced.

[0063] <Assembly Process for Cover 33> Next, the assembly process for the cover 33 will be described. As shown in Figures 12 and 13, when attaching the cover 33 to the substrate housing 21, for example, a jig 101 is used. The jig 101 may be part of an assembly device for attaching the cover 33 to the substrate housing 21. The jig 101 has a fitting hole 101A. The fitting hole 101A is a non-through hole. The contour shape of the inner circumferential surface of the fitting hole 101A corresponds to the contour shape of the outer circumferential surface of the cover 33 when viewed from a direction perpendicular to the end wall of the cover 33. If the cover 33 is not provided with a positioning projection 91, the outer circumferential surface of the cover 33 is fitted around the entire circumference of the inner circumferential surface of the fitting hole 101A. The end wall of the cover 33 is positioned inside the fitting hole 101A. The cover 33 is attached to the substrate housing 21 in a positioned state by the jig 101.

[0064] However, if the cover 33 is not provided with a positioning projection 91, the outer circumferential surface of the cover 33 will be in contact with the inner circumferential surface of the fitting hole 101A over its entire circumference. For this reason, in order to properly position the cover 33, it is necessary to strictly control the dimensional accuracy of the outer circumferential surface of the cover 33 over its entire circumference. In order to ensure the dimensional accuracy of the outer circumferential surface of the cover 33, for example, the thickness of the outer circumferential part of the cover 33 could be increased. However, the thicker the outer circumferential part of the cover 33, the larger the size of the cover 33 may become, and the heavier it may become.

[0065] As shown in Figures 14 and 15, when the cover 33 is provided with a positioning projection 91, the outer circumferential surface of the cover 33 contacts the inner circumferential surface of the fitting hole 101A only through the positioning projection 91. Therefore, in order to properly position the cover 33, it is sufficient to ensure the dimensional accuracy of the positioning projection 91 or the area around the positioning projection 91. In other words, the part of the cover 33 that needs to have its dimensional accuracy ensured is limited to the positioning projection 91 or the area around the positioning projection 91.

[0066] Therefore, by tuning the positioning projection 91 of the cover 33 or the portion of the mold corresponding to the area around the positioning projection 91, the required dimensional accuracy of the cover 33 can be easily ensured. Furthermore, since only the positioning projection 91 of the cover 33 or the portion of the mold corresponding to the area around the positioning projection 91 needs to be tuned, there is no need to increase the thickness of the outer circumference of the cover 33. The required dimensional accuracy of the cover 33 can be ensured without increasing the size and weight of the cover 33.

[0067] <Effects of the Embodiment> According to this embodiment, the following effects are achieved. (1) The motor device 11 comprises a motor 12, a substrate 32 provided at the end of the motor 12, and a cover 33 attached to the end of the motor 12 so as to cover the substrate 32. The cover 33 has an end wall facing the substrate 32 in the axial direction of the motor 12. The end wall includes a first planar wall 33A and a second planar wall 33B. The first planar wall 33A and the second planar wall 33B each extend in a direction perpendicular to the axial direction of the motor 12 and are arranged adjacent to each other. Viewed from the axial direction of the motor 12, the area of ​​the first planar wall 33A is larger than that of the second planar wall 33B, and the first planar wall 33A is provided with one or more guard ribs, which are protrusions projecting toward the side opposite to the substrate 32. The one or more guard ribs include first to third guard ribs 51 to 53.

[0068] If an object 100 collides with the cover 33 from the outside, the cover 33 may be damaged. Since the area of ​​the first planar wall 33A is larger than the area of ​​the second planar wall 33B, the bending rigidity of the first planar wall 33A is lower than that of the second planar wall 33B. Therefore, the cover 33 is particularly susceptible to damage when an object 100 collides with the first planar portion 33A. According to the motor device 11 of this embodiment, when an object 100 collides with the first planar wall 33A from the outside, there is a high probability that the object 100 will collide with the guard rib before colliding with any other surface of the first planar wall 33A. In other words, the impact of the collision of the object 100 is absorbed by the guard rib. This makes it possible to suppress damage to the first planar wall 33A and, consequently, to the cover 33. The cover 33 is protected from collisions with the object 100.

[0069] (2) The first planar wall 33A is provided with a plurality of guard ribs. The plurality of guard ribs include the first to third guard ribs 51 to 53. The plurality of guard ribs each extend in the same direction and are spaced apart in a direction perpendicular to the direction in which the guard ribs extend. The direction in which the guard ribs extend is, for example, the direction of the long side of the cover 33. With this configuration, when an object 100 collides with the first planar wall 33A from the outside, there is a high probability that the object 100 will collide with one of the plurality of guard ribs before colliding with any other surface of the first planar wall 33A. This makes it possible to adequately protect the cover 33 from collision with the object 100.

[0070] (3) One of the multiple guard ribs is provided at a position that includes the center of the first planar wall 33A when viewed from the axial direction of the motor 12. The first guard rib 51 corresponds to the guard rib provided at a position that includes the center of the first planar wall 33A. When viewed from the axial direction of the motor 12, the center of the first planar wall 33A is one of the parts of the cover 33 with the lowest bending rigidity. For this reason, by providing a guard rib at a position that includes the center of the first planar wall 33A when viewed from the axial direction of the motor 12, damage to the first planar wall 33A and, consequently, the cover 33 due to collision with the object 100 can be appropriately suppressed.

[0071] (4) The guard ribs are columnar bodies having a semicircular cross-sectional shape. The guard ribs include first to third guard ribs 51 to 53. With this configuration, regardless of the angle at which the object 100 collides with the guard ribs, the impact of the object 100 colliding with the guard ribs is easily absorbed. This makes it possible to suppress damage to the first planar wall 33A and, consequently, the cover 33, caused by collision with the object 100.

[0072] (5) The cover 33 has a plurality of reinforcing ribs. The plurality of reinforcing ribs include a plurality of first to third reinforcing ribs 61 to 63. The plurality of reinforcing ribs are provided on the surface of the first planar wall 33A opposite to the guard ribs. The guard ribs include first to third guard ribs 51 to 53. The plurality of reinforcing ribs may be provided on the surface of the first planar wall 33A opposite to the guard ribs, in an area corresponding to at least the guard ribs.

[0073] When colliding with object 100, the portion of cover 33 provided with guard ribs may receive a greater impact than other portions of cover 33 that do not have guard ribs. According to the motor device 11 of this embodiment, the reinforcing ribs reinforce at least the portion of cover 33 provided with guard ribs. This makes it possible to suppress damage to the first planar wall 33A and, consequently, the cover 33, caused by collision with object 100.

[0074] (6) The multiple reinforcing ribs include a first reinforcing rib 61 and a second reinforcing rib 62 which are arranged in a grid pattern so as to be perpendicular to each other. With this configuration, the first reinforcing rib 61 and the second reinforcing rib 62 are arranged in a grid pattern so as to be able to properly reinforce at least the portion of the cover 33 that is provided with the guard rib.

[0075] (7) The cover 33 is a resin molded product and has a gate mark GP which is the mark left by cutting the portion corresponding to the gate, which is a passage for molten resin provided in the mold. The first reinforcing rib 61 and the second reinforcing rib 62 each extend in directions perpendicular to the flow direction of the molten resin with respect to the gate during molding of the cover 33. The flow direction of the molten resin includes the first to eighth flow directions D1 to D8.

[0076] The resin molded product including the cover 33 has low strength in the direction perpendicular to the flow direction of the molten resin during molding. This is due to the directionality of the molten resin flow. According to this embodiment, by providing the first reinforcing rib 61 and the second reinforcing rib 62 so as to extend in a direction perpendicular to the flow direction of the molten resin, the portion of the cover 33 whose strength is weakened due to the directionality of the molten resin flow is reinforced. Therefore, the strength of at least the portion of the cover 33 where the guard ribs are provided can be effectively ensured.

[0077] (8) The multiple reinforcing ribs further include a third reinforcing rib 63. The third reinforcing rib 63 is provided so as to form a plurality of concentric figures centered on the gate trace GP when viewed from the axial direction of the motor 12. With this configuration, the strength of at least the portion of the cover 33 provided with the guard ribs can be further ensured.

[0078] (9) The concentric figures formed by the third reinforcing rib 63 are, for example, quadrilaterals. The third reinforcing rib 63 extends diagonally across the multiple quadrilaterals formed by the first reinforcing rib 61 and the second reinforcing rib 62 when viewed from the axial direction of the motor 12. With this configuration, the strength of at least the portion of the cover 33 where the guard rib is provided can be effectively increased.

[0079] (10) Multiple positioning protrusions 91 are provided on the outer circumferential surface of the cover 33. The multiple positioning protrusions 91 are configured to fit into the inner circumferential surface of the fitting hole 101A of the jig 101 used when attaching the cover 33 to the motor 12. With this configuration, it is sufficient to ensure the dimensional accuracy of the positioning protrusions 91 or the area around the positioning protrusions 91 on the cover 33, and it is not necessary to ensure dimensional accuracy over the entire circumference of the cover 33.

[0080] <Other Embodiments> This embodiment may be implemented with the following modifications: The area on the back surface of the first planar wall 33A where the first to third reinforcing ribs 61 to 63 are provided may be appropriately changed depending on the product. For example, the first to third reinforcing ribs 61 to 63 may be provided over the entire back surface of the first planar wall 33A. In this way, the strength of the entire first planar wall 33A can be ensured. Alternatively, the first to third reinforcing ribs 61 to 63 may be provided only in the area on the back surface of the first planar wall 33A corresponding to the first to third guard ribs 51 to 53. In this way, the strength of at least the portion of the cover 33 where the first to third guard ribs 51 to 53 are provided can be ensured.

[0081] In this embodiment, the multiple third reinforcing ribs 63 are arranged to form three quadrilaterals centered on the gate mark PG when viewed from the axial direction of the motor 12, but they may also be arranged in three concentric circles centered on the gate mark PG. The number of quadrilaterals or circles centered on the gate mark PG is not limited to three. The number of quadrilaterals or circles centered on the gate mark PG may be one or more. Even in this manner, the third reinforcing ribs 63 intersect with the flow direction of the molten resin with respect to the gate. The flow direction includes the first to eighth flow directions D1 to D8.

[0082] - The cover 33 may be configured without the third reinforcing rib 63. In this case, the first reinforcing rib 61 and the second reinforcing rib 62 may be arranged to form a plurality of concentric figures centered on the gate trace PG, for example, when viewed from the axial direction of the motor 12. The concentric figures may be, for example, squares or circles. Even in this configuration, the first reinforcing rib 61 and the second reinforcing rib 62 intersect with the flow direction of the molten resin with respect to the gate. The flow direction includes the first to eighth flow directions D1 to D8.

[0083] The gate mark PG may be formed at a position off-center from the center of the first planar wall 33A when viewed from the axial direction of the motor 12. The position of the gate mark PG formed on the cover 33 changes depending on the position of the mold gate. The first to third reinforcing ribs 61 to 63 only need to extend in a direction intersecting the flow direction of the molten resin during injection molding, and the direction in which the first to third reinforcing ribs 61 to 63 extend may be changed depending on the position of the gate mark PG. The flow direction of the molten resin can be estimated based on the position of the gate mark PG on the cover 33. Multiple gate marks GP may exist.

[0084] In this embodiment, the cover 33 has first to third guard ribs 51 to 53, but the number, arrangement, length, and spacing of the guard ribs may be appropriately changed depending on the object that is expected to collide with it. The object should collide with the guard ribs before colliding with the surface of the cover 33 other than the guard ribs. For example, the number of guard ribs may be one, four, five, or more. Also, the guard ribs may extend in the direction of the short side of the cover 33, or in the direction of the long side or in a direction intersecting the short side. Multiple guard ribs may extend in different directions from each other.

Claims

1. A motor device comprising a motor, a substrate provided at the end of the motor, and a cover attached to the end of the motor so as to cover the substrate, wherein the cover has an end wall facing the substrate in the axial direction of the motor, the end wall includes a first planar wall and a second planar wall, the first planar wall and the second planar wall each extend in a direction perpendicular to the axial direction of the motor and are arranged adjacent to each other, the area of ​​the first planar wall is larger than that of the second planar wall when viewed from the axial direction of the motor, and the first planar wall is provided with one or more guard ribs protruding away from the substrate.

2. The motor device according to claim 1, wherein one or more guard ribs include a plurality of guard ribs, each extending in the same direction and being spaced apart in a direction perpendicular to the direction in which the guard ribs extend.

3. The motor device according to claim 2, wherein one of the plurality of guard ribs is provided at a position that includes the center of the first planar wall when viewed from the axial direction of the motor.

4. The motor device according to any one of claims 1 to 3, wherein the guard rib is a columnar body having a semicircular cross-sectional shape.

5. The motor device according to any one of claims 1 to 3, wherein the cover has a plurality of reinforcing ribs, and the plurality of reinforcing ribs are provided on the surface of the first planar wall opposite to the guard ribs, in a region corresponding to the guard ribs.

6. The motor device according to claim 5, wherein the plurality of reinforcing ribs include first reinforcing ribs and second reinforcing ribs arranged in a grid pattern so as to be orthogonal to each other.

7. The motor device according to claim 6, wherein the cover is a resin molded product and has a gate mark which is the mark left by cutting a portion corresponding to a gate which is a passage for molten resin provided in the mold, and the first reinforcing rib and the second reinforcing rib each extend in a direction perpendicular to the flow direction of the molten resin with respect to the gate during molding of the cover.

8. The motor device according to claim 7, wherein the plurality of reinforcing ribs further include a third reinforcing rib, the third reinforcing rib being arranged to form a plurality of concentric figures centered on the gate mark when viewed from the axial direction of the motor.

9. The motor device according to claim 8, wherein the concentric figures are quadrilaterals, and the third reinforcing rib extends diagonally across a plurality of quadrilaterals formed by the first reinforcing rib and the second reinforcing rib when viewed from the axial direction of the motor.

10. The motor device according to any one of claims 1 to 3, wherein a plurality of positioning protrusions are provided on the outer circumferential surface of the cover, and the plurality of positioning protrusions are configured to fit into the inner circumferential surface of a fitting hole of a jig used when attaching the cover to the motor.

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