Drive device

Abstract

A drive device (1) comprises a motor (10) and a controller (50). The motor (10) has: a motor housing (15, 20, 30, 35) having a cylindrical motor case (16, 23, 33); a stator (12) fixed to the motor housing (15, 20, 30, 35); a motor wire (11) wound around the stator (12); a rotor (13) that rotates by energization to the motor wire (11); and a shaft (14) that rotates integrally with the rotor (13). The controller (50) has a substrate (53) on which electronic components (54, 55) involved in drive control of the motor (10) are mounted and a controller housing (60) that houses the substrate (53), and is provided on one side of the motor (10) in the axial direction. The controller housing (60) seals the end of the motor case (16, 23, 33) on the controller (50) side.

Description

Drive unit CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Patent Application No. 2023-116748, filed on July 18, 2023, the contents of which are incorporated herein by reference.

[0002] The present disclosure relates to a drive device.

[0003] Conventionally, there has been known an electromechanical integrated motor in which a control device is integrally formed on one side of the motor in the axial direction. For example, in Patent Document 1, a cover, a frame, and a motor case are bonded together with a sealant.

[0004] Japanese Patent Application Laid-Open No. 2017-17866

[0005] For example, in a structure that uses a sealing material or packing material to prevent water droplets from entering the interior, as in Patent Document 1, if gaps occur due to deterioration over time, there is a risk that waterproof performance will be reduced. An object of the present disclosure is to provide a drive device that can prevent water droplets and the like from entering the interior of the device.

[0006] The drive device of the present disclosure includes a motor and a controller. The motor includes a motor housing having a cylindrical motor case, a stator fixed to the motor housing, motor wires wound around the stator, a rotor that rotates when current is applied to the motor wires, and a shaft that rotates integrally with the rotor.

[0007] The controller has a circuit board on which electronic components related to motor drive control are mounted, and a controller housing that houses the circuit board. The controller housing is located on one axial side of the motor and seals the end of the motor case that faces the controller, preventing water droplets and other contaminants from entering the device.

[0008] The above and other objects, features, and advantages of the present disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which Fig. 1 is a schematic diagram of a steering system according to a first embodiment, Fig. 2 is a cross-sectional view of a drive unit according to the first embodiment, Fig. 3 is a schematic diagram illustrating the connection between a motor case and an ECU case according to the first embodiment, Fig. 4 is a flowchart illustrating an assembly process of the drive unit according to the first embodiment, Fig. 5 is an explanatory diagram illustrating the assembly of a motor case and a stator according to the first embodiment, Fig. 6 is an explanatory diagram illustrating the assembly of a rotor ASSY according to the first embodiment, Fig. 7 is an explanatory diagram illustrating the assembly of a motor ASSY according to the first embodiment, Fig. 8 is an explanatory diagram illustrating the assembly of an ECU case and an ECU-ASSY to a motor ASSY according to the first embodiment, and Fig. 9 is an explanatory diagram illustrating the assembly of a second embodiment. FIG. 12 is an explanatory diagram illustrating the assembly of an ECU case to a motor ASSY according to the second embodiment; FIG. 13 is a cross-sectional view of a drive unit according to a third embodiment; FIG. 14 is a flowchart illustrating the assembly process of a drive unit according to the third embodiment; FIG. 15 is an explanatory diagram illustrating the assembly of an inner case according to the third embodiment; FIG. 16 is an explanatory diagram illustrating the formation of a motor case according to the third embodiment and the assembly of an ECU case to a motor case; and FIG. 17 is a cross-sectional view of a drive unit according to a fourth embodiment.

[0009] A drive device according to the present disclosure will be described below with reference to the drawings. In the following, substantially identical components in multiple embodiments will be assigned the same reference numerals and descriptions thereof will be omitted.

[0010] (First embodiment) A first embodiment is shown in Figures 1 to 8. As shown in Figure 1, a drive device 1 includes a motor 10 and an ECU 50 as a controller, and is applied to an electric power steering device 8. Figure 1 shows the configuration of a steering system 90 that includes the electric power steering device 8. The steering system 90 includes a steering wheel 91, which is a steering member, a steering shaft 92, a pinion gear 96, a rack shaft 97, wheels 98, the electric power steering device 8, and the like.

[0011] The steering wheel 91 is connected to a steering shaft 92. A torque sensor 94 that detects steering torque is provided on the steering shaft 92. A pinion gear 96 is provided at the tip of the steering shaft 92. The pinion gear 96 meshes with a rack shaft 97. A pair of wheels 98 are connected to both ends of the rack shaft 97 via tie rods or the like.

[0012] When the driver turns the steering wheel 91, the steering shaft 92 connected to the steering wheel 91 rotates. The rotational motion of the steering shaft 92 is converted into linear motion of a rack shaft 97 by a pinion gear 96. A pair of wheels 98 are steered to an angle corresponding to the amount of displacement of the rack shaft 97.

[0013] The electric power steering device 8 includes the drive unit 1 and a reduction gear 89, which is a power transmission unit that reduces the speed of the rotation of the motor 10 and transmits it to the steering shaft 92. That is, the electric power steering device 8 of this embodiment is a so-called "column assist type," and the steering shaft 92 can be said to be the driven object. It may also be a so-called "rack assist type," in which the rotation of the motor 10 is transmitted to a rack shaft 97.

[0014] The motor 10 is, for example, a three-phase brushless motor. The motor 10 outputs part or all of the torque required for steering, is driven by power supplied from a battery (not shown), and rotates the reduction gear 89 forward and reverse. The drive unit 1 has the ECU 50 provided on one axial side of the motor 10, making it a so-called "mechatronically integrated" drive unit. The mechatronically integrated drive unit 1 allows the motor 10 and ECU 50 to be efficiently arranged in vehicles with limited installation space. Hereinafter, the terms "axial direction" and "radial direction" will be used to refer to the axial and radial directions of the motor 10. The lower side of the paper in FIG. 2 and other figures is the output end side.

[0015] As shown in Fig. 2, the motor 10 includes a stator 12, a rotor 13, a shaft 14, and a motor housing 15. The stator 12 is fixed to the motor housing 15, and a motor wire 11 is wound around the stator 12. The motor wire 11 is not shown in any illustration except Fig. 2. The rotor 13 is provided radially inside the stator 12 and is rotatable relative to the stator 12.

[0016] The shaft 14 is fitted into the rotor 13 and rotates integrally with the rotor 13. The shaft 14 is rotatably supported in the motor housing 15 by bearings 141 and 142. The end of the shaft 14 on the ECU 50 side is exposed from the motor housing 15 to the ECU 50 side, and is provided with a sensor magnet 145. The end of the shaft 14 opposite the ECU 50 is an output end, which is provided with a pulley 147 and is connected to the reduction gear 89.

[0017] The motor housing 15 has a motor case 16, a front frame 17, and a rear frame 18. The motor case 16 is formed into a cylindrical shape from aluminum, for example. The motor case 16 has a front frame 17 integrally molded on the output end side and an ECU case 61 (described below) integrally molded on the ECU 50 side. In this specification, the term "integrally molded" or "formed as an integrally molded product" refers to a state in which at least one preformed member A is inserted to form a member B, and members A and B may be made of the same material or different materials.

[0018] The front frame 17 is made of, for example, phenolic resin, and seals the end portion on the output end side of the motor case 16. The front frame 17 is formed with a bearing holder 171, an outer wall abutment portion 172, a flange portion 175, and the like. The bearing holder 171 is provided with a bearing 141.

[0019] The outer wall abutment portion 172 is formed in a cylindrical shape along the outer peripheral wall of the motor case 16, extending radially inward toward the ECU 50. The provision of the outer wall abutment portion 172 prevents water droplets and the like from entering the inside of the device from the connection point between the motor case 16 and the front frame 17. A plurality of flange portions 175 are formed to protrude radially outward, and are attached to the gearbox by fixing members such as screws (not shown). They may also be attached to a housing other than a gearbox.

[0020] The rear frame 18 is formed into a substantially circular plate shape from, for example, phenolic resin, and is fixed to the ECU 50 side of the motor case 16. A bearing 142 is fixed to the rear frame 18. The frames 17 and 18 hold the bearings 141 and 142, and can also be considered as bearing holding members.

[0021] The ECU 50 includes a circuit board 53, a connector 57, and an ECU housing 60. The circuit board 53 extends radially outward beyond the motor area, which is the area of ​​the motor case 16 projected in the axial direction, and is fixed to the ECU housing 60 by a fixing member 59 such as a tapping screw. Fixing members other than tapping screws may be used, and the circuit board 53 may be fixed to the ECU housing 60 by, for example, resin caulking. Hereinafter, the surface of the circuit board 53 facing the motor 10 will be referred to as a motor surface 531, and the surface opposite the motor 10 will be referred to as a cover surface 532.

[0022] Lead wires 115 taken out from each phase of the motor wire 11 are formed to extend toward the ECU 50 and are electrically connected to the substrate 53 within the motor area. In this embodiment, the lead wires 115 are soldered to the substrate 53, but the connection method is not limited to soldering as long as an electrical connection is established, and a solderless connection such as an elastic connection by press-fit or a mating connection using a socket connector may also be used.

[0023] Various electronic components such as a heating element 54, a capacitor 55, and a rotation angle sensor 56 are mounted on the substrate 53. In this embodiment, the heating element 54 and the capacitor 55 are mounted on a cover surface 532 of the substrate 53. The heating element 54 includes a switching element that constitutes an inverter that switches the current flow to the motor wires 11, a motor relay, a power relay, etc. The rotation angle sensor 56 is mounted on the motor surface 531 at a location facing the sensor magnet 145, and detects the rotation of the motor 10 by detecting the rotating magnetic field of the sensor magnet 145. Note that the rotation angle sensor 56 is not shown in the assembly description.

[0024] Connector 57 is provided outside the motor area on the motor surface 531 side of substrate 53, and connector terminals 571 are connected to substrate 53. A flange 575 extending from the main body toward the outer periphery is formed on the end of connector 57 on the substrate 53 side. Flange 575 is formed in an L-shape in cross section, with the tip protruding toward the opposite side from substrate 53.

[0025] The ECU housing 60 has an ECU case 61 and an ECU cover 71, and is formed so that a portion of the ECU case 61 extends radially outward from the motor area. The ECU case 61 is made of, for example, epoxy resin and has a generally cylindrical shape with a bottom that opens on the side opposite the motor 10. The ECU case 61 is molded integrally with the motor case 16 and seals the end of the motor case 16 on the ECU 50 side.

[0026] As shown in Figure 3, the motor case 16 is formed with sealing holes 162 that penetrate the plate thickness direction. A plurality of sealing holes 162 are formed spaced apart in the circumferential direction at the location integrally molded with the ECU case 61. When the motor case 16 and the ECU case 61 are integrally molded, the ECU case 61 is formed by sandwiching the radially inner and outer sides of the motor case 16 at the end of the motor case 16 on the ECU 50 side. Here, the resin of the ECU case 61 enters the sealing holes 162, thereby improving the joint strength.

[0027] Similarly, a plurality of sealing holes 163 penetrating in the thickness direction are formed at intervals in the circumferential direction at the portion of the motor case 16 that is integrally molded with the front frame 17. When the motor case 16 and the front frame 17 are integrally molded, the resin of the front frame 17 enters the sealing holes 163, thereby improving the joining strength.

[0028] Returning to FIG. 2, the ECU case 61 is formed with an outer wall abutment portion 611, a through hole 612, a board holding portion 613, a connector mounting portion 614, and a connector insertion hole 615 (see FIG. 8).

[0029] The outer wall abutment portion 611 is formed in a cylindrical shape along the outer peripheral wall of the motor case 16, extending radially inward toward the output end. Providing the outer wall abutment portion 611 prevents water droplets and the like from entering the inside of the device through the connection between the motor case 16 and the ECU case 61. Note that the outer wall abutment portion 611 may not be provided, and the axial length of the radially outer portion of the motor case 16 at the connection between the motor case 16 and the ECU case 61 may be equal to or less than the axial length of the radially inner portion. The same applies to the outer wall abutment portion 172 of the front frame 17. The outer wall abutment portion 611 is not shown in any figures other than Figure 2.

[0030] The through-hole 612 is provided so as to penetrate in the axial direction at a position corresponding to the shaft 14, and a sensor magnet 145 is disposed inside the through-hole 612. The board holding portion 613 is formed in the motor area, and the board 53 is fixed thereto by a fixing member 59. The connector 57 is attached to the connector attachment portion 614 with an adhesive or the like. In detail, the main body of the connector 57 is inserted into the connector insertion hole 615 with the opening exposed to the outside, and then the flange portion 575 is inserted into the connector attachment portion 614 to which the adhesive or the like has been applied, thereby attaching the connector 57 to the ECU case 61.

[0031] The ECU cover 71 is made of, for example, epoxy resin, and is provided on the cover surface 532 side of the substrate 53. The ECU cover 71 is integrally molded with the ECU case 61, and resin-seals the substrate 53, as well as the heating elements 54 and capacitors 55 mounted on the cover surface 532 side of the substrate 53. The ECU cover 71 is formed with heat dissipation fins 711 in an element mounting area, which is an axial projection of the area where the heating elements 54 are mounted.

[0032] The assembly process of the drive unit 1 of this embodiment will be described with reference to the flowchart of Fig. 4 and Fig. 5 to Fig. 8. Hereinafter, the "step" such as step S10 will be omitted and simply referred to as the symbol "S".

[0033] As shown in Fig. 5, in S10, the front frame 17 is integrally molded with the motor case 16. In S11, the stator 12 is shrink-fitted to the motor case 16. As shown in Fig. 6, in S12, the bearing 142 is fixed to the rear frame 18 by caulking, press-fitting, or the like. In S13, the bearings 141 and 142 are press-fitted into the rotor assembly in which the shaft 14 is press-fitted into the rotor 13. Note that S10, S11, and S12, S13 may be reversed in order or may be performed in parallel.

[0034] As shown in Figure 7, in S14, the rotor assembly shown on the right side of Figure 6 is assembled to the motor case 16 shown on the right side of Figure 5. Specifically, the rear frame 18 is shrink-fitted to the motor case 16. The bearing 141 is inserted into the bearing holder 171 of the front frame 17. In S15, a pulley 147 is press-fitted into the end of the shaft 14 on the output end side, and a sensor magnet 145 is press-fitted into the end of the shaft 14 on the ECU 50 side. Hereinafter, the state in which the stator 12, front frame 17, rear frame 18, etc. are assembled to the motor case 16 will be referred to as the motor assembly.

[0035] 8, in S16, the ECU case 61 is resin-molded integrally with the motor case 16 in the state of the motor assembly (see the left side of FIG. 8). In S17, adhesive is applied to the connector mounting portion 614 of the ECU case 61. In S18, the ECU-ASSY with the connector 57 attached is attached to the ECU case 61 (see the right side of FIG. 8).

[0036] In S19, the lead wires 115 are electrically connected to the substrate 53. If the connection between the lead wires 115 and the substrate 53 is a solderless connection such as a press-fit connection, the connection is completed when the ECU-ASSY is assembled to the ECU case 61 in S18, and S19 is therefore omitted. In S20, the ECU-ASSY is sealed with resin to form the ECU cover 71 (see FIG. 2). In the figure, the rotor ASSY is designated as "RA," the motor ASSY as "MA," and the ECU-ASSY as "EA" as appropriate.

[0037] For example, as a comparative example, if the rear frame is made of a metal heat sink and the heat from the heating element 54 is dissipated to the motor case 16 side, the heating element 54 needs to be mounted on the motor surface 531 side of the substrate 53 and within the motor area.

[0038] In contrast, in the drive unit 1 of this embodiment, the heating element 54 is embedded in resin in the ECU cover 71, and heat is dissipated by air radiation through the ECU cover 71, with which the heating element 54 is in direct contact. This makes it possible to mount the heating element 54 on the cover surface 532 side or outside the motor area, improving the flexibility of board design. In addition, there is no need for an intervening material such as heat dissipation gel, which is required when dissipating heat using a metal heat sink.

[0039] The ECU case 61 is molded integrally with the motor case 16 using resin insert molding, sealing the ends of the motor case 16. The front frame 17 is molded integrally with the motor case 16 using resin insert molding, sealing the ends of the motor case 16. This allows for a simple configuration that prevents water droplets, dust, and other contaminants from entering the device without any crevice corrosion. Furthermore, the ECU case 61 and front frame 17 are connected to the motor case 16 without the use of adhesive or other sealing material, eliminating gaps caused by deterioration of the sealing material over time and maintaining waterproof performance over time. It is desirable for the ECU case 61, front frame 17, and motor case 16, which are molded integrally, to be made of materials with similar linear expansion coefficients.

[0040] In this embodiment, the motor case 16 is formed from metal, and the front frame 17 is formed from resin. In other words, in this embodiment, instead of forming the motor case as a cylindrical, bottomed cylinder with the cylindrical portion and the side opposite the ECU 50 as a single component, the cylindrical motor case 16 and the approximately disk-shaped front frame 17 are separated, and the end of the metal motor case 16 is molded with resin to form the front frame 17, thereby forming the motor case 16 and the front frame 17 as a single, integrally molded component. This allows the components to be separated without compromising corrosion resistance. Furthermore, since the front frame 17 is relatively easy to form by forming it as a separate component from the motor case 16, it is possible to use a material that is highly corrosion-resistant and has relatively low fluidity.

[0041] As described above, the drive device 1 includes the motor 10 and the ECU 50. The motor 10 includes a motor housing 15 having a cylindrical motor case 16, a stator 12 fixed to the motor housing 15, motor wires 11 wound around the stator 12, a rotor 13 that rotates when current is applied to the motor wires 11, and a shaft 14 that is rotatably supported by the motor housing 15 and rotates integrally with the rotor 13.

[0042] The ECU 50 has a board 53 on which electronic components related to drive control of the motor 10 are mounted, and an ECU housing 60 that houses the board 53, and is provided on one axial side of the motor 10. The electronic components include a heating element 54 and a capacitor 55, etc. The ECU housing 60 seals the end of the motor case 16 on the ECU 50 side. More specifically, the motor case 16 and the ECU case 61 are formed as an integrally molded product, and the end of the motor case 16 on the ECU 50 side is directly sealed by the ECU case 61.

[0043] This eliminates the gap between the motor case 16 and the ECU housing 60, thereby preventing water droplets and foreign matter from entering the inside of the device through the connection between the motor 10 and the ECU 50.

[0044] The motor housing 15 has a front frame 17 that seals the end of the motor case 16 opposite the ECU 50. This allows the front frame 17 to be formed without deteriorating corrosion resistance.

[0045] The ECU housing 60 sandwiches the radially inner and outer sides of the end of the motor case 16 facing the ECU 50. The front frame 17 also sandwiches the radially inner and outer sides of the end of the motor case 16 opposite the ECU 50. The reliability of the connection can be improved by sandwiching the motor case 16 from both radial sides with the resin ECU case 61 or the front frame 17.

[0046] At the connection point between the ECU housing 60 and the motor case 16, the radially outer portion of the motor case 16 has a longer axial length than the radially inner portion. At the connection point between the front frame 17 and the motor case 16, the radially outer portion of the front frame 17 has a longer axial length than the radially inner portion. By providing outer wall abutment portions 172, 611 and forming the axial length at the radially outer side to be relatively long, it is possible to further prevent water droplets and the like from entering the interior of the device.

[0047] Second Embodiment A second embodiment is shown in Figures 9 to 12. The second to fourth embodiments differ mainly in the motor housing, so the description will be centered on the configuration related to the motor housing and will omit a description of the ECU 50 and the like.

[0048] 9 , the motor housing 20 of this embodiment has a front frame 21, a rear frame 22, and a motor case 23. The front frame 21 has a bearing holder 211, a stator contact portion 212, and a plurality of flange portions 215, and is formed of a metal such as an aluminum alloy. The front frame 21 is provided on the opposite side of the stator 21 from the ECU 50.

[0049] The bearing holder 221 holds the bearing 141. The stator contact portion 212 is formed in a cylindrical shape along the inner peripheral wall of the motor case 23. The flange portion 215 is formed to protrude radially outward and is provided so as to be attachable to the housing with a fixing member such as a screw (not shown).

[0050] The rear frame 22 has a bearing holder 221 and a stator contact portion 222, is made of a metal such as an aluminum alloy, and is provided on the ECU 50 side of the stator 12. The bearing 142 is fixed to the bearing holder 221 by press fitting or the like. The stator contact portion 222 is formed in a cylindrical shape along the inner circumferential wall of the motor case 23.

[0051] The motor case 23 is formed in a generally cylindrical shape from, for example, phenolic resin. The motor case 23 is integrally molded with the stator 12, the front frame 21, and the side surfaces of the rear frame 22. A sealing hole 231 that penetrates the motor case 23 in the thickness direction is formed at the location where the motor case 23 is connected to the ECU case 61. The resin of the ECU case 61 fills the sealing hole 231, improving the reliability of the connection.

[0052] The assembly process of the motor assembly of this embodiment will be described with reference to the flowchart of Fig. 10, and Figs. 11 and 12. Steps S30 and S31 are similar to steps S12 and S13 in Fig. 4, although the material and shape of the rear frame 22 are different from those of the first embodiment.

[0053] 11 , in S32, the front frame 21, the stator 12, and the rotor assembly are stacked. At this time, on the radially outer side, the front frame 21, the stator 12, and the rear frame 22 are stacked in this order from the output end side, and the stator abutment portion 212 of the front frame 21 and the stator abutment portion 222 of the rear frame 22 are in contact with the stator 12. This determines the axial position.

[0054] In S33, the radially outer sides of the front frame 21, stator 12, and rear frame 22 are sealed with resin to form the motor case 23. The processing from S15 onwards is the same as in the first embodiment, and as shown in Figure 12, a pulley 147 is press-fitted into the end of the shaft 14 on the output end side, and a sensor magnet 145 is press-fitted into the end of the shaft 14 on the ECU 50 side. Then, the ECU case 61 is resin-molded integrally with the motor case 23. The assembly of the ECU 50 is the same as in the above embodiment, so a description thereof will be omitted.

[0055] In this embodiment, the stator 12, the front frame 21, and the rear frame 22 are resin-sealed together in the motor case 23. This increases the fixing strength between the components. It also reduces the thickness required to ensure fixing strength, contributing to a reduction in the weight of the drive unit 1. Furthermore, by molding the sides of the stator 12 and the frames 21 and 22 together and forming the motor case 23 by integral molding, it is possible to prevent water droplets and the like from entering the inside of the device without using a sealant or the like.

[0056] In this embodiment, the motor case 23 is made of resin. Specifically, the motor housing 20 has a front frame 21 provided on one axial side of the stator 12, and a rear frame 22 provided on the other axial side of the stator 12. The motor case 23 is formed radially outward when the front frame 21, stator 12, and rear frame 22 are stacked in the axial direction. This allows the front frame 21, stator 12, and rear frame 22 to be more firmly connected to the motor case 23, thereby improving the reliability of the connection of the components. This also provides the same effects as the above embodiment.

[0057] 13 to 16 show a third embodiment. A motor housing 30 of this embodiment has a front inner case 31, a rear inner case 32, and a motor case 33.

[0058] The front inner case 31 has a bearing holder 311 and a stator holder 312, and is formed from, for example, an aluminum alloy into a generally cylindrical shape with a bottom that opens toward the ECU 50. The bearing holder 311 holds the bearing 141. The stator holder 312 is also formed into a cylindrical shape, and the end on the ECU 50 side is provided between the stator 12 and the motor case 33.

[0059] The rear inner case 32 has a bearing holder 321 and a stator holder 322, and is formed from, for example, an aluminum alloy or the like in a generally cylindrical shape with a bottom that opens on the side opposite the ECU 50. A bearing 142 is fixed to the bearing holder 321. The stator holder 322 is also cylindrical. The end of the stator holder 322 opposite the ECU 50 is located between the stator 12 and the motor case 33, and its tip surface abuts against the front inner case 31.

[0060] The motor case 33 is formed in a generally cylindrical shape from, for example, phenolic resin. The motor case 33 is integrally molded with the side surfaces of the inner cases 31 and 32. Sealing holes 331 are formed in the motor case 33 at locations where the motor case 33 connects to the ECU case 61, penetrating the motor case 33 in the plate thickness direction. The resin of the ECU case 61 fills the sealing holes 331, improving connection reliability. The motor case 33 is formed with a plurality of flanges 335 that protrude radially outward and are used for attachment to a housing with fixing members such as screws (not shown).

[0061] The assembly process for the motor assembly of this embodiment will be described with reference to the flowchart in Fig. 14 and Figs. 15 and 16. As shown in the lower left of Fig. 15, in S40, the stator 12 is shrink-fitted into the front inner case 31 so that the bearing holder 311 faces the opposite side from which the lead wires 115 of the stator 12 are extracted. The front inner case 31 and the stator 12 may be fixed by a method other than shrink-fitting. The same applies to fixing the stator 12 to the rear inner case 32.

[0062] As shown in the upper part of Fig. 15, in S41, the bearing 142 is press-fitted into the rear inner case 32, and in S42, the bearings 141, 142 are press-fitted into the rotor ASSY. As shown in the lower right part of Fig. 15, in S43, the rear inner case 32 is placed over the stator 12 and shrink-fitted so that the opening faces the front inner case 31. The abutment positions of the inner cases 31, 32 need only be such that the stator 12 can be shrink-fitted to both, and may be offset from the center position in the axial direction of the stator 12.

[0063] In S44, as shown in Figure 16, the front inner case 31 and the rear inner case 32 are molded integrally with resin to form the motor case 33. The processing from S15 onwards is the same as in the first embodiment, with the pulley 147 press-fitted into the end of the shaft 14 on the output end side, and the sensor magnet 145 press-fitted into the end of the shaft 14 on the ECU 50 side. Then, the ECU case 61 is molded integrally with the motor case 33 with resin. As the assembly of the ECU side is the same as in the above embodiment, a description thereof will be omitted.

[0064] In this embodiment, the stator 12 is fixed to the inner cases 31 and 32 and the outside is sealed with resin, thereby preventing water droplets and the like from entering the inside of the device without using a sealant, etc. Also, reliability in terms of corrosion resistance can be improved.

[0065] In this embodiment, the motor housing 30 has a front inner case 31 fixed to the radial outside of the stator 12 and extending to one axial side of the stator 12, and a rear inner case 32 fixed to the radial outside of the stator 12 and extending to the other axial side of the stator 12. The motor case 33 is formed radially outward from the front inner case 31 and the rear inner case 32. This makes it possible to form the motor case 33 relatively easily, and also provides the same effects as the above-described embodiment.

[0066] (Fourth Embodiment) A fourth embodiment is shown in Figure 17. A motor housing 35 of this embodiment has a front inner case 36, a front frame 37, a rear inner case 32, and a motor case 33. In this embodiment, a front frame 37 having a bearing holder 371 that holds a bearing 141 is formed separately from the front inner case 36. In the assembly process, before shrink-fitting the stator 12 into the front inner case 36, the front frame 37 is fixed to the front inner case 36 by shrink-fitting, press-fitting, or the like. The subsequent assembly process is the same as in the third embodiment.

[0067] In this embodiment, by making the front frame 37 separate from the front inner case 36, the front inner case 36 can be formed by press working, which improves productivity. In addition, the same effects as those of the above embodiment can be achieved.

[0068] In the embodiment, the front frame 17 corresponds to the "frame," the front frame 21 corresponds to the "first frame," the rear frame 22 corresponds to the "second frame," the front inner case 31 corresponds to the "first inner case," the rear inner case 32 corresponds to the "second inner case," the ECU 50 corresponds to the "controller," and the ECU housing 60 corresponds to the "controller housing."

[0069] Other Embodiments In the above embodiment, an example was shown in which phenolic resin was mainly used as the material for the front frame and rear frame, and epoxy resin was used as the material for the controller housing. In other embodiments, the controller housing may be made of a material other than epoxy resin. Also, the motor housing may be made of a material other than phenolic resin. For example, to further improve heat dissipation, the rear frame may be made of a metal with good thermal conductivity, such as an aluminum alloy. Also, in the first embodiment, the motor case may be made of resin. That is, it may be "a drive device according to any one of aspects 1 to 6, in which the motor case is made of resin."

[0070] In the above embodiment, the motor case is formed by integrally molding the front frame and the motor case as separate members. In other embodiments, the motor case may be formed into a cylindrical shape with a bottom that opens toward the ECU, and the motor case and the front frame may be formed into a single member. As a supplementary note, even if the motor case is formed into a cylindrical shape with a bottom, it is still included in the concept of a "cylindrical motor case."

[0071] In the above embodiment, when the motor case and the controller housing are integrally molded, a sealing hole is formed in the motor case, and the motor case is integrally molded with the controller housing sandwiching the inner and outer sides in the radial direction. In other embodiments, when the motor case and the ECU housing are integrally molded, the motor case does not have to be sandwiched between the inner and outer sides in the radial direction. Also, the sealing hole may be omitted. The same applies to the connection point between the motor case and the front frame.

[0072] In the above embodiment, the heat dissipation ribs are provided in the axial projection area of ​​the heat-generating component. In other embodiments, depending on the thermal mass of the controller housing, the heat dissipation ribs may be omitted, or a separate structure for heat dissipation (for example, a metal plate with good thermal conductivity or a flow path through which a cooling fluid can flow) may be provided.

[0073] In the above embodiment, the connector is provided on the motor side of the circuit board, with its opening facing the output end in the axial direction. In other embodiments, the connector may be provided on the cover side of the circuit board, or the opening may face in a different direction. Multiple connectors may also be provided. The element arrangement on the circuit board may differ from that in the above embodiment. Furthermore, the electronic components do not need to be embedded in the controller housing as long as heat dissipation from the electronic components can be ensured.

[0074] In the above embodiment, the controller is formed to extend radially outward beyond the motor area. In other embodiments, the controller may be provided within the motor area. In the above embodiment, the drive device is applied to an electric power steering device. In other embodiments, the drive device may be applied to an in-vehicle device other than an electric power steering device, or may be applied to a device other than an in-vehicle device.

[0075] As described above, the present disclosure is not limited to the above-described embodiment, and can be implemented in various forms without departing from the spirit of the present disclosure.

[0076] The present disclosure has been described based on the embodiments. However, the present disclosure is not limited to the embodiments and structures. The present disclosure also encompasses various modifications and variations within the scope of equivalents. Furthermore, various combinations and forms, as well as other combinations and forms including only one element, more than one element, or less than one element, are also within the scope and spirit of the present disclosure.

Claims

1. A drive device comprising: a motor housing (15, 20, 30, 35) having a cylindrical motor case (16, 23, 33), a stator (12) fixed to the motor housing, motor wires (11) wound around the stator, a rotor (13) that rotates when current is applied to the motor wire, and a motor (10) having a shaft (14) that rotates integrally with the rotor; and a controller (50) provided on one axial side of the motor, the controller housing having a board (53) on which electronic components (54, 55) related to drive control of the motor are mounted, and a controller housing (60) that accommodates the board, the controller housing sealing the end of the motor case on the controller side.

2. A drive unit according to claim 1, wherein said controller housing sandwiches the radially inner and outer sides of the end of said motor case on said controller side.

3. The drive unit according to claim 2, wherein the controller housing has a longer axial length at a radially outer portion of the motor case than at a radially inner portion of the motor case at a connection point with the motor case.

4. A drive device according to any one of claims 1 to 3, wherein the motor housing has a frame (17) sealing the end of the motor case opposite the controller.

5. A drive unit according to claim 4, wherein said frame sandwiches the radially inner and outer sides of the end of said motor case opposite to said controller.

6. A drive unit according to claim 5, wherein at a connection point between said frame and said motor case, a radially outer portion of said frame is longer in the axial direction than a radially inner portion of said frame.

7. The drive unit according to claim 1, wherein the motor case is made of resin.

8. A drive unit as described in claim 7, wherein the motor housing (20) has a first frame (21) provided on one axial side of the stator and a second frame (22) provided on the other axial side of the stator, and the motor case (23) is formed radially outward of the first frame, the stator, and the second frame stacked together.

9. A drive device as described in claim 7, wherein the motor housing (30) has a first inner case (31) fixed to the radial outside of the stator and extending to one axial side of the stator, and a second inner case (32) fixed to the radial outside of the stator and extending to the other axial side of the stator, and the motor case (33) is formed radially outside the first inner case and the second inner case.

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