motor

Abstract

A motor is provided. The motor has a rotor, a stator, a bearing, a motor case, a bearing holder, a bus bar unit, and a circuit board. The bearing holder holds the bearing and covers an opening of the motor case, has a holder protrusion. The holder protrusion is disposed at a position radially outward of the motor case, has a terminal through hole that penetrates in an axial direction. The bus bar unit has a bus bar terminal and a bus bar holder. The bus bar terminal is connected to the bus bar, extends to an axial lower side and protrudes from a lower surface of the holder protrusion to the axial lower side, through an inside of the terminal through hole. The circuit board has a circuit terminal. The circuit terminal extends to the axial lower side and protrudes from the lower surface of the holder protrusion to the axial lower side, through the inside of the terminal through hole, and is connected to the bus bar terminal. The bus bar holder has a cylindrical terminal guide portion. The terminal guide portion extends in the axial direction and is disposed inside the terminal through hole, and the bus bar terminal and the circuit terminal are housed inside in a contact manner.

Description

Technical Field

[0001] This invention relates to motors. Background Technology

[0002] Conventional motors consist of a rotor, stator, bearings, housing, bracket (bearing cage), and busbar unit. The rotor has a rotor shaft extending axially. The stator is radially opposed to the rotor. The bearings support the rotor shaft for rotation. The housing houses the stator. The bracket covers the opening in the housing and secures the bearings. Additionally, the bracket has axially extending welding holes (terminal through holes).

[0003] The busbar unit has: a main body (busbar) connected to a conductor led out from the stator; and busbar terminals extending axially from the main body. The busbar terminals are connected in a welding operation hole to a connection terminal (circuit terminal) connected to an external power source (for example, see Patent Document 1).

[0004] Patent Document 1: Japanese Patent Application Publication No. 2008-79466

[0005] However, in existing motors, there is a possibility of short circuits occurring when the busbar terminals and connection terminals come into contact with the bracket. Summary of the Invention

[0006] Therefore, the object of the present invention is to provide a motor capable of preventing short circuits.

[0007] An exemplary motor of the present invention includes a rotor, a stator, bearings, a motor housing, a bearing cage, a busbar unit, and a circuit board. The rotor has a shaft extending along a rotation axis. The stator is radially opposed to the rotor. The bearing supports the shaft for rotation. The motor housing houses the stator and has an axially upward opening. The bearing cage holds the bearing and covers the opening in the motor housing. The busbar unit is electrically connected to the stator and is disposed on the bearing cage. The circuit board is disposed axially upward on the busbar unit and is electrically connected to the busbar unit. The bearing cage has a cage protrusion. The cage protrusion projects radially outward beyond the motor housing and has a terminal through-hole extending axially. The busbar unit includes a busbar, a busbar terminal, and a busbar cage. The busbar is disposed around the bearing and connected to a wire leading from the stator. The busbar terminal is connected to the busbar, extends axially downward, passes through the interior of the terminal through-hole, and protrudes axially downward from the lower surface of the cage protrusion. The busbar retainer is made of insulating material and covers the outer surface of the busbar and busbar terminals. The circuit board has circuit terminals. The circuit terminals extend axially downwards and pass through the interior of the terminal through-hole, protruding axially downwards from the lower surface of the retainer protrusion, and are connected to the busbar terminals. The busbar retainer has a cylindrical terminal guide. The terminal guide extends axially and is disposed inside the terminal through-hole, housing the busbar terminals and circuit terminals in contact within it.

[0008] According to the exemplary invention, a motor capable of preventing short circuits can be provided. Attached Figure Description

[0009] Figure 1 This is a perspective view of a motor according to an embodiment of the present invention.

[0010] Figure 2 This is an exploded perspective view of the motor according to an embodiment of the present invention.

[0011] Figure 3 This is a longitudinal sectional perspective view of the motor according to an embodiment of the present invention.

[0012] Figure 4 This is an enlarged longitudinal sectional view showing a portion of the motor according to an embodiment of the present invention.

[0013] Figure 5 This is an exploded perspective view of the motor housing according to an embodiment of the present invention.

[0014] Figure 6 This is a perspective view of the busbar unit of the motor according to an embodiment of the present invention.

[0015] Figure 7 This is an exploded perspective view of the busbar unit of the motor according to an embodiment of the present invention.

[0016] Figure 8 This is an enlarged longitudinal sectional view showing a portion of the motor according to an embodiment of the present invention.

[0017] Figure 9 This is an enlarged longitudinal sectional view showing a portion of the motor according to an embodiment of the present invention.

[0018] Figure 10 This is a perspective view of a busbar cover according to an embodiment of the present invention.

[0019] Label Explanation

[0020] 1: Motor; 20: Rotor; 21: Shaft; 22: Rotor core; 23: Rotor magnet; 30: Stator; 31: Back of core; 32: Gear; 33: Coil section; 33a: Wire; 34: Insulating component; 41: Upper bearing; 42: Lower bearing; 50: Housing; 51: Motor housing; 51a: Opening; 52: Bearing cage; 52a: Bearing cage opening; 53: Cover; 60: Busbar unit; 61: Busbar cage; 61a: Base 61b: Terminal retainer; 61c: Terminal guide; 61d: Terminal insertion port; 62U, 63V, 64W: Busbar; 62a, 63a, 64a: Base; 62b, 63b, 64b: Connecting part; 62c, 63c, 64c: Terminal part; 65: Busbar terminal; 70: Motor cover; 80: First circuit board; 81: Sensor; 82: Connector part; 83: Second circuit board (circuit board); 84: Circuit terminal; 90: Magnet 91: Retaining part; 92: Sensor magnet; 100: Motor body; 200: Control part; 511: Side wall part; 512: Bottom wall part; 512a: Lower bearing retaining part; 512b: Bottom wall through hole; 521: Intermediate wall part; 521a: Cage protrusion; 521b: Terminal through hole; 521c: Sealing recess; 521d: Fixing recess; 522: Peripheral wall part; 523a: Upper cylinder part; 523b: Lower cylinder part; 524: Recess; 525: Shaft 526: Through hole for retainer; 527: Annular connection; 527: Retainer flange; 527a: Retainer threaded hole; 528: Busbar cover; 528a: Cover; 528b: Flange; 528c: Flange protrusion; 528d: Fixing pin; 531: Cover flange; 531a: Cover hole; 540: O-ring; 611f: First inclined surface; 612f: Second inclined surface; 621b, 631b, 641b: Wire holding part; C: Central axis; P: Lower end. Detailed Implementation

[0021] Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Furthermore, Figure 1The direction in which the central axis C of the motor 1 extends is simply referred to as the "axial direction," and the radial and circumferential directions centered on the central axis C of the motor 1 are simply referred to as the "radial direction" and the "circumferential direction." In addition, "axial direction," "radial direction," and "circumferential direction" are only names used for illustrative purposes and do not limit the actual positional relationship and direction.

[0022] <1. Structure of the Motor>

[0023] A motor according to an exemplary embodiment of the present invention will be described. Figure 1 , Figure 2 These are perspective views and exploded perspective views of motor 1 according to an embodiment of the present invention. Figure 3 This is a longitudinal sectional perspective view of motor 1. Figure 4 This is a longitudinal sectional view showing an enlarged portion of motor 1. Figure 5 This is an exploded perspective view of the shell 50.

[0024] The motor body 100 and control unit 200 of motor 1 are integrated into the housing 50. The motor body 100 has a rotor 20, a stator 30, an upper bearing (bearing) 41, a lower bearing 42, a bearing cage 52, and a busbar unit 60.

[0025] The control unit 200 is located axially above the motor body 100 and controls the rotation of the rotor 20. The control unit 200 includes a first circuit board 80, a second circuit board (circuit board) 83, and a connector 82. The connector 82 is electrically connected to the first circuit board 80 and provides drive current from an external power source to the first circuit board 80 and the second circuit board 83.

[0026] The motor body 100 and the control unit 200 are electrically connected via a circuit terminal 84 connected to the busbar unit 60, which in turn is connected to the second circuit board (circuit board) 83. The connection structure between the circuit terminal 84 and the busbar unit 60 will be described in detail later.

[0027] The housing 50 houses the motor body 100 and the control unit 200, and includes a motor housing 51, a bearing cage 52, and a cover 53.

[0028] That is, the motor 1 has a rotor 20, a stator 30, an upper bearing (bearing) 41, a motor housing 51, a bearing cage 52, a busbar unit 60, and a second circuit board (circuit board) 83.

[0029] <2-1. Structure of the Motor Housing>

[0030] The motor housing 51 is formed as a bottomed cylindrical shape, housing the rotor 20 and stator 30. The motor housing 51 has a side wall portion 511 and a bottom wall portion 512. The side wall portion 511 extends axially upward and is cylindrical. An opening 51a is formed on the upper surface of the side wall portion 511. The lower surface of the side wall portion 511 is covered by the plate-shaped bottom wall portion 512. The bottom wall portion 512 has a lower bearing retaining portion 512a. The lower bearing retaining portion 512a is disposed on the central axis C, and its upper surface is recessed axially. A lower bearing 42 is housed and held in the lower bearing retaining portion 512a. An axially penetrating bottom wall through hole 512b is formed on the bottom surface of the lower bearing retaining portion 512a.

[0031] <2-2. Structure of the bearing cage>

[0032] The bearing cage 52 holds the upper bearing (bearing) 41 and covers the opening of the motor housing 51. The bearing cage 52 is disposed on the axial upper side of the motor housing 51 and is formed into a bottomed cylindrical shape. The bearing cage 52 internally houses the busbar unit 60 and the upper bearing 41. The bearing cage 52 has a middle wall portion 521, a peripheral wall portion 522, an upper cylindrical portion 523a, a lower cylindrical portion 523b, a recess 524, a bearing cage through hole 525, an annular connecting portion 526, and a cage flange portion 527.

[0033] The intermediate wall portion 521 is formed in a plate shape, covering the opening 51a of the motor housing 51. The intermediate wall portion 521 has a cage protrusion 521a. That is, the bearing cage 52 has a cage protrusion 521a. The cage protrusion 521a protrudes radially outward from the motor housing 51. The cage protrusion 521a is formed with a terminal through hole 521b that extends axially. The terminal through hole 521b is covered from the lower surface of the cage protrusion 521a by a busbar cover 528.

[0034] The peripheral wall portion 522 extends axially upward from the periphery of the intermediate wall portion 521, forming a cylindrical shape. The upper surface of the peripheral wall portion 522 is open to form the bearing cage opening portion 52a.

[0035] The upper cylindrical portion 523a surrounds the central axis C and extends axially upward from the upper surface of the intermediate wall portion 521 to form a cylindrical shape. The upper cylindrical portion 523a houses the magnet holding portion 90 and the sensor magnet 91, which will be described later, inside.

[0036] The lower cylindrical portion 523b surrounds the central axis C and extends axially downward from the lower surface of the intermediate wall portion 521 to form a cylindrical shape. The upper bearing 41 is housed and held in the lower cylindrical portion 523b. The upper cylindrical portion 523a and the lower cylindrical portion 523b are axially connected.

[0037] A recess 524 is disposed radially outside the upper cylindrical portion 523a and the lower cylindrical portion 523b, and is recessed axially downward from the upper surface of the intermediate wall portion 521. When viewed from above, the recess 524 is annular, surrounding the upper cylindrical portion 523a and the lower cylindrical portion 523b. A bearing cage through-hole 525 is formed, extending axially through the bottom surface of the recess 524. Multiple bearing cage through-holes 525 are arranged circumferentially. In this embodiment, 12 bearing cage through-holes 525 are provided.

[0038] An annular connecting portion 526 protrudes axially downward from the lower surface of the intermediate wall portion 521, forming an annulus surrounding the recess 524. The annular connecting portion 526 is pressed into the inner surface of the side wall portion 511 of the motor housing 51 with an O-ring 540 sandwiched between its outer circumferential surfaces. Thus, the annular connecting portion 526 is fitted into the opening of the motor housing 51, and the bearing cage 52 and the motor housing 51 are fixed.

[0039] The cage flange portion 527 protrudes radially outward from the upper end of the peripheral wall portion 522. The cage flange portion 527 has four locations on the outer periphery of the peripheral wall portion 522. A cage threaded hole 527a extending axially is provided in the cage flange portion 527.

[0040] <2-3. Structure of the Cover>

[0041] The cover 53 is plate-shaped and covers the opening 52a of the bearing cage. The cover 53 has a cover flange 531. The cover flange 531 protrudes radially outward from the outer periphery of the cover 53. The cover flange 531 is provided at four locations on the outer periphery of the cover 53. A cover hole 531a is provided in the cover flange 531, which extends axially. The cover 53 and the bearing cage 52 are fixed by aligning the cover hole 531a with the threaded hole 527a of the cage and tightening the threads.

[0042] <3. Rotor Structure>

[0043] The rotor 20 has a shaft 21, a rotor core 22, and a rotor magnet 23. The shaft 21 forms a rotating shaft extending along the central axis C and is cylindrical in shape. That is, the rotor 20 has a shaft 21 extending along the axis of rotation. The shaft 21 is supported by an upper bearing 41 and a lower bearing 42 so that it can rotate about the axis.

[0044] The lower end of the shaft 21 protrudes outward from the motor housing 51 through the bottom wall through hole 512b. The upper end of the shaft 21 is disposed inside the upper cylinder portion 523a.

[0045] The rotor core 22 is cylindrical, and a shaft 21 is fixed inside by pressing. Rotor magnets 23 are disposed on the radial outer surface of the rotor core 22, and multiple magnets are arranged circumferentially. The rotor core 22 and rotor magnets 23 rotate integrally with the shaft 21.

[0046] <4. Structure of the stator>

[0047] The stator 30 is disposed radially outside the rotor 20. That is, the stator 30 and the rotor 20 are radially opposed. The stator 30 is formed in a cylindrical shape, and the rotor 20 is disposed inside the stator 30. The stator 30 has an iron core back 31, teeth 32, coil portion 33, and insulating component 34.

[0048] The back of the iron core 31 is cylindrical and concentric with the shaft 21. The outer circumferential surface of the back of the iron core 31, i.e. the outer circumferential surface of the stator 30, is fitted into the inner circumferential surface of the side wall portion 511 of the motor housing 51.

[0049] The teeth 32 extend radially inward from the inner circumferential surface of the back surface 31 of the iron core. Multiple teeth 32 are provided and are arranged at equal intervals in the circumferential direction of the inner circumferential surface of the back surface 31 of the iron core. In this embodiment, 12 teeth 32 are provided.

[0050] The coil section 33 is constructed by winding a wire 33a around an insulating member 34. The insulating member 34 is mounted on each tooth section 32. The end of the wire 33a wound around each tooth section 32 extends axially upward and passes through the bearing cage through hole 525, and is connected to the second circuit board 83 via a busbar unit 60 disposed inside the bearing cage 52.

[0051] When a drive current is supplied to the coil section 33, a magnetic field is generated, and the rotor 20 rotates due to this magnetic field.

[0052] <5. Structure of the sensor magnet>

[0053] The sensor magnet 91 is a ring-shaped permanent magnet with N and S poles arranged on the surface opposite to the sensor 81. The sensor magnet 91 is fitted into the inner circumferential surface of the cylindrical magnet holding part 90, which is fitted into the upper end of the shaft 21.

[0054] In this embodiment, a sensor magnet 91 is fixed inside the magnet holding portion 90. Thus, the sensor magnet 91 is connected to the shaft 21 via the magnet holding portion 90 and is configured to rotate together with the shaft 21. Alternatively, the sensor magnet 91 can be directly fixed to the front end of the shaft 21 using an adhesive or the like.

[0055] <6. Structure of Circuit Board 1 and Circuit Board 2>

[0056] The first circuit board 80 and the second circuit board (circuit board) 83 are housed within the bearing retainer 52. The first circuit board 80 and the second circuit board (circuit board) 83 are positioned on the axial upper side of the busbar unit 60.

[0057] The first circuit board 80 and the second circuit board 83 extend perpendicularly to the central axis C, forming a plate shape. The second circuit board 83 is disposed on the axially upper side of the first circuit board 80 with a predetermined gap. When viewed from the axial direction, the first circuit board 80 and the second circuit board 83 are arranged overlappingly.

[0058] The lower surface of the first circuit board 80 is axially opposed to the upper surface of the upper cylindrical portion 523a of the bearing cage 52 with a gap between them. The first circuit board 80 and the second circuit board 83 are electrically connected by a connecting pin (not shown).

[0059] A motor cover 70 is disposed between the first circuit board 80 and the upper surface of the upper cylinder 523a. The motor cover 70 is formed in the shape of a circular plate and is disposed on the axial upper side of the busbar unit 60. This prevents dust from adhering to the busbar unit 60.

[0060] A circuit terminal 84 is connected to the lower surface of the second circuit board 83. The circuit terminal 84 extends axially downward and passes through the interior of the terminal through hole 521b, protrudes axially downward from the lower surface of the cage protrusion 521a, and connects to the busbar terminal 65 described later. Thus, the second circuit board 83 is electrically connected to the busbar unit 60. The first circuit board 80 and the second circuit board 83 output motor drive signals to the stator 40 via the busbar unit 60.

[0061] A sensor 81 for detecting the rotational position of the rotor 20 is mounted on the lower surface of the first circuit board 80. The sensor 81 is positioned axially above the sensor magnet 91. Therefore, the sensor 81 is close to the sensor magnet 91, allowing for the appropriate use of a magnetoresistive element in the sensor 81.

[0062] Sensor 81 detects the rotational position of rotor 20 by detecting the magnetic flux of sensor magnet 91. It then outputs a motor drive signal corresponding to the rotational position of rotor 20, controlling the drive current supplied to coil section 33. Therefore, the drive of motor 1 can be controlled.

[0063] <7. Structure of Busbar Unit>

[0064] Figure 6 , Figure 7 These are perspective views and exploded perspective views of busbar unit 60. Busbar unit 60 is electrically connected to stator 30 and is mounted on bearing cage 52. Furthermore, busbar unit 60 is positioned radially outward of upper bearing 41 within bearing cage 52.

[0065] Busbar unit 60 includes busbar holder 61, busbars 62U, 63V, and 64W, and busbar terminals 65. Busbars 62U, 63V, and 64W are composed of conductive plate-shaped components with different shapes. Busbars 62U, 63V, and 64W correspond to the U-phase, V-phase, and W-phase, respectively. In this embodiment, busbar 62U corresponds to the U-phase, busbar 63V corresponds to the V-phase, and busbar 64W corresponds to the W-phase.

[0066] <7-1. Structure of the busbar>

[0067] The busbar 62U has a base 62a, a connecting portion 62b, and a terminal portion 62c. The base 62a extends circumferentially and is formed into a top arc shape.

[0068] A connecting portion 62b protrudes radially inward from the radially inner surface of the base 62a, and its front end bends axially downward. Four connecting portions 62b are provided, arranged at equal intervals in the circumferential direction. Each connecting portion 62b has a wire holding portion 621b. The wire holding portion 621b protrudes radially inward from the front end of the connecting portion 62b and is generally U-shaped when viewed from above. A terminal portion 62c extends linearly outward from the radially outer surface of the base 62a.

[0069] The busbar 63V has a base 63a, a connecting portion 63b, and a terminal portion 63c. The base 63a extends circumferentially and is formed into a top arc shape.

[0070] A connecting portion 63b protrudes radially inward from the radially inner surface of the base 63a, and its front end bends axially downward. Four connecting portions 63b are provided, arranged at equal intervals in the circumferential direction. Each connecting portion 63b has a wire holding portion 631b. The wire holding portion 631b protrudes radially inward from the front end of the connecting portion 63b and is generally U-shaped when viewed from above. A terminal portion 63c protrudes axially upward from the radially outer surface of the base 63a, and its front end bends radially outward.

[0071] The busbar 64W has a base 64a, a connecting portion 64b, and a terminal portion 64c. The base 64a extends circumferentially and is formed into a top arc shape.

[0072] A connecting portion 64b protrudes radially inward from the radially inner surface of the base 64a, and its front end bends axially downward. Four connecting portions 64b are provided, arranged at equal intervals in the circumferential direction. Each connecting portion 64b has a wire holding portion 641b. The wire holding portion 641b protrudes radially inward from the front end of the connecting portion 64b and is generally U-shaped when viewed from above. A terminal portion 64c protrudes axially upward from the radially outer surface of the base 64a, and its front end bends radially outward.

[0073] Bases 64a, 63a, and 62a are formed as thin plates and are sequentially overlapped in the axial direction with spacers (not shown). This allows the busbar unit 60 to be made thinner in the axial direction. The spacers are formed, for example, of an insulating material such as resin.

[0074] With bases 64a, 63a, and 62a overlapping, connecting portions 62b, 63b, and 64b are arranged sequentially at equal intervals along the circumferential direction. At this time, the lower ends of connecting portions 62b, 63b, and 64b are positioned at approximately the same axial height. Furthermore, the multiple connecting portions 62b, 63b, and 64b arranged sequentially at equal intervals along the circumferential direction protrude radially inward from the radially inner surface of each base 62a, 63a, and 64a, enabling radial miniaturization of the busbar unit 60.

[0075] The conductor holding portions 621b, 631b, and 641b are electrically connected to the front end of the conductor 33a extending axially upward from the stator 30 via laser welding or the like. Specifically, the connecting portion 62b extends axially downward from the base 62a and is connected to the conductor 33a. The connecting portion 63b extends axially downward from the base 63a and is connected to the conductor 33a. The connecting portion 64b extends axially downward from the base 64a and is connected to the conductor 33a.

[0076] <7-2. Structure of Busbar Terminals>

[0077] Busbar terminals 65 are L-shaped, with one end extending radially. One end of each busbar terminal 65 is welded to terminal portions 62c, 63c, and 64c, respectively. Thus, busbar terminals 65 are connected to busbars 62U, 63V, and 64W, respectively. The other end of each busbar terminal 65 extends axially downward and is electrically connected to a circuit terminal 84. The connection structure between the busbar terminals 65 and the circuit terminal 84 will be described in detail later. In this embodiment, the busbar terminals 65 are formed separately from terminal portions 62c, 63c, and 64c, but this is not a limitation. For example, terminal portions 62c and 65, 63c and 64c and 64c may be integrally formed.

[0078] <7-3. Structure of Busbar Cage>

[0079] The busbar retainer 61 is formed of an insulating material such as resin. The busbar retainer 61 covers the outer surfaces of the busbars 62U, 63V, and 64W, which include bases 62a, 63a, and 64a, and terminal portions 62c, 63c, and 64c, as well as the busbar terminals 65. In this embodiment, the busbars 62U, 63V, and 64W, and the busbar terminals 65 are embedded in the busbar retainer 61 and fixed by insert molding. Thus, the busbars 62U, 63V, and 64W are insulated from each other through the busbar retainer 61.

[0080] The busbar retainer 61 has a base retainer 61a, a terminal retainer 61b, and a terminal guide 61c. The base retainer 61a covers the axially overlapping bases 62a, 63a, and 64a, and is formed in a generally annular shape when viewed from the axial direction.

[0081] The terminal retainer 61b extends in a straight line from the radial outer surface of the base retainer 61a outward in a radial direction. The terminal retainer 61b is provided in three places in the circumferential direction, respectively covering the terminal portions 62c, 63c, and 64c arranged in the circumferential direction and one end of the busbar terminal 65 extending in the radial direction.

[0082] Terminal guide portion 61c is connected to the radially outer end of each terminal holder 61b. Terminal guide portion 61c extends axially and is cylindrical. The upper and lower surfaces of terminal guide portion 61c are open. Terminal guide portion 61c covers the other end of each axially extending busbar terminal 65. Thus, each busbar terminal 65 connected to the U-phase, V-phase, and W-phase is insulated from each other through terminal guide portion 61c.

[0083] Each busbar terminal 65 has a portion exposed inside the terminal guide 61c, and is not covered by the terminal guide 61c (see reference). Figure 8 ).

[0084] The terminal guide portion 61c has an opening on its upper surface for a terminal insertion port 61d, and an opening on its lower surface for a terminal outlet 61e (see reference). Figure 8 ).

[0085] <8. Connection structure between busbar terminals and circuit terminals>

[0086] Figure 8 This is a magnified cross-sectional perspective view showing busbar terminal 65 and circuit terminal 84. Figure 9 This is a cross-sectional perspective view showing the terminal guide 61c enlarged. The terminal guide 61c is disposed inside the terminal through hole 521b. The circuit terminal 84 is inserted into the terminal insertion port 61d and contacts the busbar terminal 65. Thus, the busbar terminal 65 and the circuit terminal 84 are electrically connected within the terminal guide 61c.

[0087] Busbar terminal 65 and circuit terminal 84 pass through the interior of terminal through hole 521b while being housed inside terminal guide portion 61c. Therefore, busbar terminal 65 and circuit terminal 84 are reliably insulated from bearing cage 52, preventing short circuits.

[0088] Furthermore, the busbar terminal 65 and the circuit terminal 84 protrude axially downward from the terminal outlet 61e, and their lower ends are reliably connected by welding. At this time, the lower ends of the busbar terminal 65 and the circuit terminal 84 are located axially downward from the lower surface of the bearing cage 52. Therefore, welding efficiency can be improved even with the busbar cover 528 removed.

[0089] Furthermore, the lower end 61e of the terminal guide 61c is located axially lower than the lower end P of the terminal through hole 521b. This ensures that the circuit terminal 84 and the busbar terminal 65 maintain an insulating distance from the bearing cage 52, further preventing short circuits.

[0090] The terminal guide portion 61c has an inclined portion 61f. The inclined portion 61f is inclined inward on the inner circumferential surface of the terminal guide portion 61c as it moves axially downward from the terminal insertion port 61d. As a result, the circuit terminal 84 can be smoothly guided from the terminal outlet 61e along the inclined portion 61f into the interior of the terminal guide portion 61c. Therefore, the assembly workability of the motor 1 and the second circuit board 83 is improved. In addition, by forming the terminal insertion port 61d larger, even if the lower end of the circuit terminal 84 wobbles radially or circumferentially during insertion, the circuit terminal 84 can be reliably guided into the interior of the terminal guide portion 61c.

[0091] The inclined portion 61f has a first inclined surface 611f and a second inclined surface 612f in the opposing direction between the busbar terminal 65 and the circuit terminal 84. The first inclined surface 611f is disposed on the side of the busbar terminal 65. The second inclined surface 612f is disposed on the side of the circuit terminal 84. The inclination angle of the second inclined surface 612f relative to the axial direction is larger than the inclination angle of the first inclined surface 611f relative to the axial direction. As a result, the upper end of the second inclined surface 612f can be formed radially separate from the busbar terminal 65, and even if the lower end of the circuit terminal 84 wobbles radially or circumferentially during insertion, the circuit terminal 84 can be guided into the interior of the terminal guide portion 61c more reliably.

[0092] Furthermore, the axial length of the second inclined surface 612f is longer than the axial length of the first inclined surface 611f. As a result, the upper end of the second inclined surface 612f can be formed more radially separate from the busbar terminal 65, thereby enabling more reliable guidance of the circuit terminal 84 toward the busbar terminal 65 side.

[0093] <9. Structure of the busbar>

[0094] Busbar cover 528 is, for example, a resin molded article. Busbar cover 528 is disposed on the lower surface of the cage protrusion 521a, covering the terminal through hole 521b. This prevents the lower ends of the soldered circuit terminal 84 and busbar terminal 65 from protruding outside the bearing cage 52. Busbar cover 528 is installed after the lower ends of the circuit terminal 84 and busbar terminal 65 have been soldered.

[0095] The busbar cover 528 has a cylindrical cover portion 528a and a flange portion 528b. The cover portion 528a covers the lower ends of the busbar terminal 65 and the circuit terminal 84, and the upper surface of the cover portion 528a is open. The flange portion 528b extends outward from the upper peripheral edge of the cover portion 528a and is fixed to the lower surface of the retainer protrusion 521a.

[0096] The flange portion 528b has a flange protrusion 528c and a pair of retaining pins 528d. The flange protrusion 528c protrudes axially upward from the upper surface of the flange portion 528b and is formed in an annular shape surrounding the opening of the cover portion 528a. The pair of retaining pins 528d protrudes axially upward from the upper surface of the flange portion 528b and is disposed across the flange protrusion 528c.

[0097] The cage protrusion 521a has a sealing recess 521c and a fixing recess 521d (see reference). Figure 8 The fixing recess 521d is recessed from the lower surface toward the axial upward side, and the fixing pin 528d is disposed inside it. By pressing the fixing pin 528d into the fixing recess 521d, the busbar cover 528 can be easily fixed to the lower surface of the retainer protrusion 521a.

[0098] The sealing recess 521c is recessed axially upward from the lower surface of the cage protrusion 521a, forming an annular shape surrounding the terminal through hole 521b. The flange protrusion 528c is disposed inside the sealing recess 521c, which is filled with sealing material. As a result, the sealing performance between the upper surface of the flange 528b and the lower surface of the cage protrusion 521a is improved.

[0099] In this embodiment, the sealing material is an adhesive, which has a sealing function, and the manifold cover 528 is fixed to the peripheral wall portion 522 of the bearing cage 52. Furthermore, since it takes time for the adhesive to reliably fix the manifold cover 528d into the fixing recess 521d, it also functions as a temporary fixation. This maintains the manifold cover 528 in a positioned state relative to the bearing cage 52. Moreover, multiple axially extending compression ribs are formed on the outer periphery of the fixing pin 528.

[0100] The embodiments shown above are merely illustrative of the present invention. The structure of the embodiments can also be appropriately modified within the scope of the technical concept of the present invention. In addition, embodiments or multiple modifications can be combined to implement them as possible.

[0101] Industrial availability

[0102] The motor of the present invention can be used, for example, in an electric power steering system used to assist steering wheel operation in vehicles such as automobiles. Furthermore, the present invention is suitable for power steering systems, but can also be used in other air supply devices, etc.

Claims

1. A motor having: A rotor having a shaft extending along the axis of rotation; The stator is radially opposed to the rotor; A bearing that supports the shaft so that it can rotate; A motor housing that houses the stator and has an axially upward opening; A bearing cage that holds the bearing and covers the opening in the motor housing; Busbar unit, electrically connected to the stator, is disposed on the bearing cage; and A circuit board, which is disposed on the axial upper side of the busbar unit and electrically connected to the busbar unit, The bearing cage has a cage protrusion that projects radially outward from the motor housing. The cage protrusion has a terminal through hole that extends axially. The bus bar unit has: A busbar, which is arranged around the bearing, is connected to a wire drawn from the stator; A busbar terminal, which is connected to the busbar, extends axially downward and passes through the interior of the terminal through hole, and protrudes axially downward from the lower surface of the retainer protrusion; as well as A busbar retainer, which is composed of insulating components, covers the outer surfaces of the busbar and the busbar terminals. The circuit board has a circuit terminal that connects to the busbar terminal, the circuit terminal extending axially downward and passing through the interior of the terminal through hole, and protruding axially downward from the lower surface of the retainer protrusion. The busbar retainer has a cylindrical terminal guide that extends axially and is disposed inside the terminal through-hole, the terminal guide housing the busbar terminal and the circuit terminal in contact with each other inside.

2. The motor according to claim 1, wherein, The lower end of the terminal guide is located axially lower than the lower end of the terminal through hole.

3. The motor according to claim 1 or 2, wherein, The terminal guide has an opening on its upper surface for inserting the circuit terminal, and an opening on its lower surface for protruding the busbar terminal and the circuit terminal.

4. The motor according to claim 3, wherein, The terminal guide has an inclined portion that is inclined inward on its inner circumferential surface as it moves from the terminal insertion port toward the axially downward side.

5. The motor according to claim 4, wherein, The inclined portion has a first inclined surface and a second inclined surface in the direction opposite to the busbar terminal and the circuit terminal, the first inclined surface being disposed on the side of the busbar terminal and the second inclined surface being disposed on the side of the circuit terminal. The tilt angle of the second inclined surface relative to the axial direction is larger than the tilt angle of the first inclined surface relative to the axial direction.

6. The motor according to claim 5, wherein, The axial length of the second inclined surface is longer than the axial length of the first inclined surface.

7. The motor according to any one of claims 1 to 6, wherein, The motor also has a busbar cover disposed on the lower surface of the cage protrusion, which covers the terminal through hole. The busbar cover has the following features: A cylindrical cover that covers the lower ends of the busbar terminals and the circuit terminals, with an opening on the upper surface of the cover; as well as A flange portion, which extends outward from the upper peripheral edge of the cover portion, is fixed to the lower surface of the retainer protrusion. The flange portion has an annular flange protrusion that protrudes axially upward from the upper surface. The cage protrusion has an annular sealing recess that is recessed from the lower surface toward the axially upward side, and this sealing recess surrounds the terminal through hole. The flange protrusion is disposed inside the sealing recess filled with sealing material.

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