Drive unit

Abstract

To provide a driving device capable of assembling a cover with a motor by a snap fitting system in a pseudo cylinder part of the cover.SOLUTION: In a driving device 100, a motor 10 and a controller 20 are integrally constructed. A metal rear frame 30 is provided to an end part on the controller 20 side in a shaft direction of the motor 10. In a substrate 40, an electronic component constructing the controller 20 is mounted. A bottomed cylindrical cover 60 includes a plurality of flexible engagement parts 67 and 68 which can be engaged to a plurality of fixing engagement parts 37 and 38 provided to a side surface of the rear frame 30 in a snap fit system, and is fixed to the rear frame 30 to cover the substrate. The cover 60 includes a pseudo cylindrical part 63 in which at least one part of a projection shape in the shaft direction is constructed by an arc or a curve based on the arc. A flat surface part 632 is formed on one part of the side surface of the pseudo cylindrical part 63. At least one flexible engagement part 67 is provided to the flat surface part 632 of the pseudo cylindrical part 63.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] 2. Description of the Related Art In a conventional drive device in which a motor and a controller that drives and controls the motor are integrally configured, a technique is known in which the motor and a cover that covers a circuit board of the controller are assembled by bolting, crimping, or the like.

[0003] Patent Document 1 also discloses a configuration in which an end cover and a connector holder, and the connector holder and the holder are fixed together by snap-fitting. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2012-152091 A Summary of the Invention [Problem to be solved by the invention]

[0005] Since motors are cylindrical, in order to use space efficiently, covers are generally designed to be cylindrical as well. However, there is a problem in that a snap-fit ​​structure cannot be provided on a cylindrical curved surface. In the following, the term "quasi-cylindrical portion" is used to refer to shapes that are not strictly cylindrical but include shapes such as an elliptical cylinder that is similar to a cylinder.

[0006] The present invention has been made in view of the above-mentioned points, and its object is to provide a drive device in which the cover and the motor can be assembled by a snap-fit ​​method at the pseudo-cylindrical portion of the cover. [Means for solving the problem]

[0007] The drive device according to the present invention is configured by integrating a motor (10) including a stator (11) and a rotor (12) with a controller (20) that drives and controls the motor. The drive device includes a metal rear frame (30), a base plate (40), and Integral resin molding and a cylindrical cover (60) with a bottom.

[0008] The rear frame is provided at an end of the motor on the controller side in the axial direction. The circuit board is provided on the opposite side of the rear frame from the motor, and has electronic components that constitute the controller mounted thereon. The cover has a plurality of flexible locking portions (67, 68) that can be engaged in a snap-fit ​​manner with a plurality of fixed locking portions (37, 38) provided on the side surface of the rear frame, and is fixed to the rear frame to cover the board.

[0009] The cover has a pseudo-cylindrical portion (63) whose axial projection shape is at least partially formed of a circular arc or a curve quasi-circular arc, and a rectangular tubular portion (64) whose side includes two extension surfaces (643) that are parallel to each other and connect to the side surfaces of the pseudo-cylindrical portion, and one front surface (644) that is a plane perpendicular to the two extension surfaces. The pseudo-cylindrical portion and the rectangular tubular portion are provided symmetrically with respect to a reference plane (X) that includes the rotation axis of the motor.

[0010] doubt Side of cylindrical part The angle from the motor's rotation axis (O) to the reference plane is in the range of 30° to 60°. The flexible engaging portion has a U-shaped frame plate shape that extends from a portion near the open end (66) of the cover in the direction opposite the top surface portion (62) of the cover and beyond the open end. multiple The flexible locking portion is symmetrically arranged with respect to a reference plane; Flat surface of pseudo-cylinder , and the extension surface of the rectangular tube portion It is provided in.

[0011] In the drive unit of the present invention, the cover and the motor can be assembled by a snap-fit ​​method at the pseudo-cylindrical portion of the cover. Also, when changing the model from a drive unit that does not use a snap-fit ​​assembly method to the drive unit of the present invention, the change in the silhouette of the cover and the circuit board can be minimized. [Brief description of the drawings]

[0012] [Figure 1] FIG. 4 is a perspective view of a drive device according to an embodiment before a cover is attached and in which components mounted on a board are omitted. [Diagram 2] 2 is an axial cross-sectional view of line II-O-II in FIG. 1 after the cover has been installed. [Diagram 3] FIG. 2 is a front view of the cover of the drive unit of FIG. 1; [Figure 4]4 is a left side view of the cover of the drive unit of FIG. 1 (view taken in the direction of arrow IV in FIG. 3). [Diagram 5] 3 is a plan view of a cover of the drive unit of FIG. 1 (viewed in the direction of the V arrow of FIG. 3). [Figure 6] 6 is a bottom view of the cover of the drive unit of FIG. 1 (view taken in the direction of arrow VI in FIG. 3 ). [Figure 7] FIG. 2 is a plan view of a substrate of the drive unit of FIG. 1; [Figure 8] 13A and 13B are diagrams showing the positions of flat surfaces of a pseudo-cylinder portion in a cover of a drive unit according to one embodiment and another embodiment, respectively. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] (One embodiment) A drive device according to an embodiment of the present invention will be described with reference to the drawings. The drive device of this embodiment is applied to an electric power steering device of a vehicle, and is configured integrally with a motor that outputs steering assist torque and a controller that drives and controls the motor. In other words, the drive device of this embodiment is a so-called "mechatronically integrated" motor. Mechatronically integrated motors are disclosed in Patent Document 1 (JP Patent Publication No. 2012-152091, corresponding US Publication: US2012 / 0161590A1) and the like.

[0014] In the following drawings, the rotation axis of the motor 10 is indicated as "O". The direction of the motor rotation axis O is simply referred to as the "axial direction". First, the overall configuration of the drive device 100 will be described with reference to Figs. 1 and 2. Fig. 1 shows a perspective view before the cover 60 is attached. The electronic components mounted on the board 40 are not shown. Fig. 2 shows an axial cross-sectional view after the cover 60 is attached. The output shaft side of the motor 10 shown in the lower part of Fig. 2 is referred to as the "front side", and the cover 60 side shown in the upper part of Fig. 2 is referred to as the "rear side". The controller 20 is arranged coaxially with the rotation axis O on the rear side of the motor 10.

[0015] The driving device 100 is configured integrally with a motor 10, which is a three-phase brushless motor, and a controller 20 that drives and controls the motor 10. The motor 10 includes a stator 11, a rotor 12, a front frame 13, a coil 14, a shaft 15, a joint 16, bearings 17 and 18, a rear frame 30, and the like.

[0016] A three-phase coil 14 is wound around the stator 11. The coil 14 is connected to a substrate 40 via a motor terminal (not shown). A controller 20 controls the supply of electricity to the coil 14, thereby forming a rotating magnetic field in the stator 11. The rotor 12 is provided inside the stator 11, and a shaft 15 is fixed to the center of the rotor 12. The shaft 15 is rotatably supported by a front bearing 17 held by a front frame 13 and a rear bearing 18 held by a rear frame 30.

[0017] A plurality of permanent magnets are provided on the outer periphery of rotor 12. Rotor 12 rotates about shaft 15 due to a rotating magnetic field formed in stator 11 by energizing coil 14. A joint 16 for transmitting rotation is provided at the front end of shaft 15.

[0018] The rear frame 30 is made of metal such as an aluminum alloy, and is provided at the end of the motor 10 on the controller 20 side in the axial direction. A shaft hole 32 through which the shaft 15 is inserted is formed in the center of the rear frame 30. The rear bearing 18 is held on the front side of the rear frame 30, and a board 40 is fixed to an end face 34 on the rear side. The rear frame 30 supports the board 40 and the rear bearing 18, and also functions as a heat sink that receives heat dissipated from electronic components mounted on the board 40.

[0019] A frame end portion 36 having a larger radial dimension is provided at the end of the rear frame 30 on the motor 10 side. The frame end portion 36 of the rear frame 30 and the front frame 13 are fastened with through-hole bolts 19. A plurality of protruding fixing engagement portions 37, 38 are provided on the side surface of the frame end portion 36.

[0020] Specifically, the fixed locking portion 37 is provided at a position corresponding to a flexible locking portion 67 formed on a pseudo cylindrical portion 63 of the cover 60, which will be described later. The fixed locking portion 38 is provided at a position corresponding to a flexible locking portion 68 formed on a rectangular tubular portion 64 of the cover 60. Thus, a total of four fixed locking portions 37, 38, including the back side in FIG. 1, are provided on the side surfaces of the frame end portion 36 of the rear frame 30.

[0021] Since the rear frame 30 is made of metal, the fixed locking portions 37, 38 do not deform. Therefore, they are called "fixed locking portions" in contrast to the flexible locking portions 67, 68 which are made of resin. As will be described later, in this embodiment, the flexible locking portions 67, 68 can be engaged with the fixed locking portions 37, 38 by a snap-fit ​​method. As a guide for this engagement, as shown in FIG. 2, it is preferable that the fixed locking portions 37, 38 are formed so that their protrusions are inclined outward from the rear side toward the front side.

[0022] The board 40 is fixed to an end surface 34 on the rear side of the rear frame 30. That is, the board 40 is provided on the opposite side of the motor 10, i.e., the rear side, of the rear frame 30. The board 40 has electronic components that constitute the controller 20 mounted thereon. Specifically, a plurality of switching elements that constitute an inverter, coils and capacitors that constitute a noise filter, a microcomputer and ICs that constitute a control unit, a current sensor, a rotation angle sensor, etc., are mounted thereon.

[0023] The drive device 100 of this embodiment has a "side-connector type" configuration in which the connector 50 protrudes in a direction perpendicular to the motor shaft O. As will be described later with reference to Fig. 7, the connector 50 is connected to the rectangular plate portion 44 of the substrate 40 via a plurality of terminals 52. A power cable that supplies power to the controller 20 and a signal cable that communicates signals between the controller 20 and a control circuit or the like of the vehicle are connected to the connector 50.

[0024] The cover 60 has a bottomed cylindrical shape, and is fixed to the rear frame 30 from the rear side of the substrate 40 to cover the substrate 40. In this embodiment, the cover 60 is integrally formed from resin, and is fixed to the rear frame 30 by a snap-fit ​​method. The configuration of the cover 60 in this embodiment will be described in detail below.

[0025] 1 to 6 and 8(a), the configuration of the cover 60 will be described in detail. The cover 60 includes a pseudo-cylindrical portion 63 and a rectangular tubular portion 64 that extend from a top surface portion 62 to the sides. The pseudo-cylindrical portion 63 and the rectangular tubular portion 64 are provided symmetrically with respect to a reference plane X that includes the motor rotation axis O.

[0026] 5 and 6, which are axial projection views, a circle and a rectangle are connected symmetrically with respect to a reference line X passing through the center of the circle. The length of the side of the rectangle perpendicular to the reference line X is equal to or less than the diameter of the circle. Therefore, the central angle of the arc is 180° or more. In this embodiment, the central angle α of the arc of the pseudo cylindrical portion 63 is approximately 240°.

[0027] Specifically, the pseudo-cylindrical portion 63 is defined as "a portion in which at least a part of the axial projection shape is composed of a circular arc or a curve quasi-arc." In the present embodiment, the pseudo-cylindrical portion 63 has a part of the axial projection shape composed of a circular arc. Since the cover 60 covers the motor 10, it is basically cylindrical in shape conforming to the silhouette of the motor 10.

[0028] A flat surface portion 632 whose axial projection shape is represented by a straight line is formed on a part of the side surface of the pseudo cylindrical portion 63. The portion other than the flat surface portion 632 forms a curved surface portion 631 whose axial projection shape is represented by a circular arc. In this embodiment, a total of two flat surface portions 632 are formed, one on each side of the reference plane X. The flat surface portions 632 are formed so that the angle from the motor rotation axis O to the reference plane X is in the range of approximately 30° to approximately 60°.

[0029] 8(a), the flat surface portion 632 of the pseudo cylindrical portion 63 is formed inside a virtual curved surface Svc formed by extending the curved surface portions 631 adjacent to both sides. More specifically, a straight line connecting the end points of the curved surface portions 631 adjacent to both sides, i.e., a straight line equivalent to a chord of a circle, forms the flat surface portion 632. Since the thickness of the cover 60, which is a resin molded product, is almost constant, the inner wall of the flat surface portion 632 is located inside a virtual inner wall curved surface formed by extending the inner wall of the curved surface portion 631.

[0030] The rectangular tube portion 64 includes three planes on its side, namely, two extension planes 643 and one front plane 644. The two extension planes 643 are parallel to each other and are planes that connect to the side of the pseudo cylindrical portion 63. The front plane 644 is a plane that is perpendicular to the two extension planes 643. As shown by the dashed line in FIG. 4, the front plane 644 is formed with a notch 645 through which the connector 50 is inserted. In this way, the rectangular tube portion 64 of the cover 60 has the function of covering the terminal portion of the board 40 that is connected to the connector 50 and the base portion of the connector 50.

[0031] A flexible locking portion 67 is formed on each flat surface portion 632 of the pseudo cylindrical portion 63, and a flexible locking portion 68 is formed on each extended surface portion 643 of the rectangular tube portion 64. In other words, the cover 60 of this embodiment has a total of four flexible locking portions 67, 68. The four flexible locking portions 67, 68 are disposed symmetrically with respect to the reference plane X.

[0032] The flexible locking portions 67, 68 extend beyond the opening end 66 in the opposite direction to the top surface portion 62 from a portion of the flat surface portion 632 or the extended surface portion 643 close to the opening end 66. The flexible locking portions 67, 68 are substantially U-shaped frame plate-shaped, and locking holes 670, 680 are formed on the inside of the frame. The locking holes 670, 680 are formed, for example, by using a slide mold in a resin molding die.

[0033] The flexible locking portions 67, 68 are elastically deformable such that their tip sides spread outward due to the elasticity of the resin. When the cover 60 is placed directly above the rear frame 30, the flexible locking portions 67, 68 overlap the fixed locking portions 37, 38 before elastic deformation. As the tip sides of the flexible locking portions 67, 68 spread outward, the frame portions get over the protrusions and the fixed locking portions 37, 38 are housed inside the locking holes 670, 680. In this manner, the flexible locking portions 67, 68 can be engaged with the fixed locking portions 37, 38 of the rear frame 30 in a snap-fit ​​manner.

[0034] In addition, a bolt shielding portion 65 is provided on the side of the pseudo cylindrical portion 63 opposite the rectangular cylindrical portion 64, protruding in a low height range along an open end 66. The bolt shielding portion 65 covers the head of the through-hole bolt 19.

[0035] Next, the configuration of the substrate 40 of the drive device 100 will be described in detail with reference to Fig. 1, Fig. 7, and Fig. 8(a). As shown in Fig. 7, the substrate 40 of this embodiment has an outer edge formed in a shape that follows the inner wall of the cover 60. That is, the substrate 40 has a pseudo disk portion 43 that corresponds to the pseudo cylinder portion 63 of the cover 60, and a rectangular plate portion 44 that corresponds to the rectangular tube portion 64. The rectangular plate portion 44 is connected to the connector 50 via a plurality of terminals 52. Also, the substrate 40 has a corresponding flat portion 432 whose outer edge is formed by a straight line at a position facing the inner wall of the flat portion 632 of the pseudo cylinder portion 63 in the pseudo disk portion 43.

[0036] 8(a), in this embodiment, the flat surface 632 of the cover 60 is formed inside the imaginary curved surface Svc. Therefore, if the pseudo disk portion 43 of the substrate 40 is formed of a simple arc, the outer edge of the substrate 40 will interfere with the inner wall of the cover 60 depending on the distance between the inner wall of the cover 60 and the substrate 40. Therefore, in this embodiment, a corresponding flat surface portion 432 is formed on the substrate 40 in correspondence with the flat surface portion 632 of the cover 60.

[0037] (Effects of this embodiment) (1) The cover 60 of this embodiment has a plurality of flexible locking portions 67, 68 that can be engaged by a snap-fit ​​method with a plurality of fixed locking portions 37, 38 provided on the side surface of the rear frame 30. Some of the flexible locking portions 67 are provided on a flat portion 632 formed on part of the side surface of the pseudo cylindrical portion 63.

[0038] As a result, in the driving device 100 of this embodiment, the cover 60 and the motor 10 can be assembled by a snap-fit ​​method at the pseudo-cylindrical portion 63 of the cover 60. This makes it possible to reduce the number of parts and assembly steps compared to bolt fastening or crimp fastening.

[0039] In addition, when changing from a drive unit that is not assembled by a snap fit method to the drive unit of this embodiment, there is a need to avoid increasing the size in order to ensure that it can be mounted on a vehicle, and to avoid significantly reducing the size in order to ensure the board mounting area. In response to this need, this embodiment can minimize changes in the silhouette of the cover 60 and the board 40.

[0040] (2) The flat surface portion 632 of the pseudo cylindrical portion 63 is formed inside the imaginary curved surface Svc formed by extending the curved surface portions 631 adjacent to both sides. This makes it possible to avoid an increase in the silhouette when changing the model from a drive device that is not assembled by a snap-fit ​​method to the drive device of this embodiment.

[0041] (3) The outer edge of the substrate 40 is formed in a shape that follows the inner wall of the cover 60, and a corresponding flat surface portion 432 having an outer edge formed by a straight line is formed in a position facing the inner wall of the flat surface portion 632 of the pseudo-cylindrical portion 63. This makes it possible to avoid interference between the cover 60 and the substrate 40 while maximizing the area of ​​the substrate 40.

[0042] (4) In the drive device 100 of the "side connector type" in which the connector 50 protrudes from the side surface of the cover 60 in a direction perpendicular to the motor shaft O, the cover 60 includes a rectangular tube portion 64 in which the connector 50 is disposed, in addition to the pseudo cylindrical portion 63. A flexible locking portion 68 is formed on the extension surface portion 643 of the rectangular tube portion 64, which is separate from the flexible locking portion 67 formed on the flat portion 632 of the pseudo cylindrical portion 63. This realizes a configuration suitable for the side connector type.

[0043] (5) As shown in Figures 5 and 6, the pseudo cylindrical portion 63 and the rectangular cylindrical portion 64 are provided symmetrically with respect to the reference plane X, and the multiple flexible locking portions 67, 68 are disposed symmetrically with respect to the reference plane X. This improves the balance of the fastening forces on both sides of the reference plane X.

[0044] (6) The cover 60 is integrally formed from resin, which reduces the weight of the drive unit 100 and the number of parts.

[0045] (Other embodiments) (a) The "quasi-cylindrical portion" of the cover 60 includes a portion where at least a part of the axial projection shape is formed by a circular arc, as well as a portion where at least a part of the axial projection shape is formed by a "curve quasi-arc." A "curve quasi-arc" typically means a curve that is convex outward from the center, such as an ellipse. In other words, a shape such as an elliptical cylinder that can form a flat surface like a cylindrical portion is defined as a "quasi-cylindrical portion," which is an expanded concept of a "cylindrical portion" in the narrow sense.

[0046] (b) The flexible locking portion and the fixed locking portion that constitute the snap-fit ​​method may be configured such that one is convex and the other is concave. In other words, contrary to the configuration of the above embodiment, the flexible locking portions 67, 68 of the cover 60 may be configured as convex, and the fixed locking portions 37, 38 of the rear frame 30 may be configured as concave.

[0047] (c) In contrast to the embodiment shown in Fig. 8(a), as shown in Fig. 8(b), the flat surface 632 of the cover 60 may be formed outside the imaginary curved surface Svc. This configuration prevents the inner wall of the cover 60 from interfering with the substrate 40. In addition, when modifying a mold for a cover that does not have a flat surface, the cavity mold can be corrected by adjusting the cutting direction.

[0048] (d) Even if the flat surface 632 of the cover 60 is formed inside the imaginary curved surface Svc, if the substrate 40 is a circular shape that is one size smaller than the inner wall of the cover 60 and does not interfere with the flat surface 632, the corresponding flat surface 432 of the substrate 40 does not need to be formed.

[0049] (e) For example, in a driving device 100 using a "top-out connector system" in which a connector protrudes axially from the top surface portion 62, the cover 60 may not include the rectangular tube portion 64 and may be composed of only the pseudo-cylindrical portion 63. In this case, all of the flexible locking portions 67 are provided on the flat portion 632 of the pseudo-cylindrical portion 63. The multiple flexible locking portions 67 are arranged, for example, point-symmetrically with respect to the motor rotation axis O, improving the balance of the fastening force in the circumferential direction.

[0050] (f) The number and arrangement of the multiple flexible locking portions 67, 68 in the cover 60 are not limited to those in the above embodiment. In addition, the multiple flexible locking portions 67, 68 may be arranged asymmetrically with respect to the reference plane X instead of symmetrically with respect to the reference plane X as shown in Figures 5 and 6.

[0051] (g) (delete)

[0052] (h) The drive device of the present invention may be applied to in-vehicle devices other than electric power steering devices, and to various devices other than devices mounted on vehicles.

[0053] The present invention is not limited to the above-described embodiment, and can be embodied in various forms without departing from the spirit of the present invention. [Explanation of symbols]

[0054] 10...Motor, 20... controller, 30···Rear frame, 37, 38...Fixed locking part, 40... Substrate, 60···Cover, 63: Quasi-cylindrical portion; 632: Planar portion; 67, 68...Flexible locking part, 100...Drive unit.

Claims

1. A drive device in which a motor (10) including a stator (11) and a rotor (12) and a controller (20) for controlling the drive of the motor are integrally configured, a metal rear frame (30) provided at an end of the motor on the controller side in the axial direction; a substrate (40) provided on the opposite side of the motor with respect to the rear frame and on which electronic components constituting the controller are mounted; a bottomed cylindrical cover (60) integrally formed of resin, the bottomed cylindrical cover (60) having a plurality of flexible engaging portions (67, 68) that can be engaged in a snap-fit ​​manner with a plurality of fixed engaging portions (37, 38) provided on a side surface of the rear frame, and fixed to the rear frame to cover the substrate; Equipped with The cover has a pseudo-cylindrical portion (63) in which at least a part of the projection shape in the axial direction is formed of a circular arc or a curve quasi-circular arc, and a rectangular tubular portion (64) including on its side two extension surface portions (643) which are parallel to each other and are connected to the side surfaces of the pseudo-cylindrical portion, and one front surface portion (644) which is a plane perpendicular to the two extension surface portions, the pseudo-cylindrical portion and the rectangular tubular portion being disposed symmetrically with respect to a reference plane (X) which includes a rotation axis of the motor, A flat portion (632) is formed on a side surface of the pseudo-cylindrical portion at an angle of 30° to 60° from the rotation axis (O) of the motor with respect to the reference plane, the flexible engaging portion is a U-shaped frame plate extending from a portion near the opening end (66) of the cover in a direction opposite to the top surface portion (62) of the cover beyond the opening end, The flexible engagement portions are disposed symmetrically with respect to the reference plane, and are provided on the planar portion of the pseudo-cylinder portion and the extended surface portion of the rectangular tube portion.

2. 2. The drive device according to claim 1, wherein the flat surface of the pseudo cylindrical portion is formed inside an imaginary curved surface formed by extending curved surface portions (631) adjacent to both sides of the pseudo cylindrical portion.

3. the substrate has an outer edge formed in a shape that conforms to the inner wall of the cover, 3. The drive device according to claim 2, wherein a corresponding flat portion (432) having an outer edge formed of straight lines is formed at a position facing an inner wall of the flat portion of the pseudo-cylindrical portion.

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