JP2023006607A - motor unit - Google Patents

Abstract

To provide a motor unit capable of preventing foreign matters of welding sputtering from entering inside a motor and of suppressing increase in size of the entire unit, in a motor unit with a controller integrated to one side i an axial direction of a motor part.SOLUTION: A motor unit 1 comprises: a motor part 3 that has a rotor 20, and a stator 30 including a motor terminal 53; a housing 11 that accommodates the motor part; and a controller 5 located at one side in an axial direction. The controller has: a substrate 66 connected to the motor terminal via a substrate terminal 51; and a cover 70 that surrounds a substrate accommodation space K2 for accommodating the substrate together with the housing. A flat plate part 72 of the cover has: a flat plate main body part 72a; and a step part 73 located closer to another side in the axial direction than the flat plate main body part. The step part is provided with a through-hole 77 penetrating in the axial direction. The substrate terminal and the motor terminal are inserted into the through-hole, and connected with each other in a recessed space surrounded by the step part.SELECTED DRAWING: Figure 1

Description

The present invention relates to a motor unit.

In recent years, for the purpose of simplifying the assembly process, etc., a motor unit in which a control section is integrated on one side in the axial direction of a motor body (motor section) is being adopted. In this case, it is necessary to connect the stator of the motor body and the board of the control unit.
In Patent Document 1, a hole is provided in a side surface of a heat sink provided on one axial side of a motor housing. Motor terminals extending from the motor body and board terminals extending from the control board are arranged inside the holes, and these terminals are welded and connected.

Japanese Patent No. 5063722

However, in the configuration of Patent Document 1, since the terminals are connected by welding in the holes provided in the heat sink, welding spatter may enter the motor.

In view of the above circumstances, the present invention provides a motor unit in which a control section is integrated on one side in the axial direction of the motor section, in which foreign matter such as welding spatter is prevented from entering the motor, and the overall size of the unit is reduced. One of the purposes is to suppress it.

One aspect of the motor unit of the present invention comprises: a motor section having a rotor and a stator including motor terminals; a housing accommodating the motor section; a control unit located at the The control unit includes a board connected to the motor terminals via board terminals, and a cover surrounding a board accommodation space that accommodates the board together with the housing. The cover includes a flat plate portion that covers one axial side of the board accommodation space. The flat plate portion includes a flat plate body portion and a stepped portion located on the other side in the axial direction of the flat plate body portion. The stepped portion is provided with a through hole penetrating in the axial direction. The board terminals and the motor terminals are inserted into the through holes and connected to each other within the recessed space surrounded by the stepped portion.

According to one aspect of the present invention, in a motor unit in which a control unit is integrated on one axial side of a motor unit, foreign matter such as welding spatter is prevented from entering the motor, and an increase in the size of the entire unit is suppressed. can be suppressed.

FIG. 1 is a cross-sectional view along the axial direction of the motor unit 1 of this embodiment. 2 is an enlarged view of a main part of FIG. 1. FIG. FIG. 3 is a cross-sectional view similar to FIG. 1, showing the positional relationship between the recess and the electronic component. FIG. 4 is a plan view of the cover viewed from the axial direction. FIG. 5 is a cross-sectional view similar to FIG. 1 showing a first modification of the present embodiment. FIG. 6 is a cross-sectional view similar to FIG. 2 showing a second modification of the present embodiment. FIG. 7 is a plan view similar to FIG. 4 showing a third modification of this embodiment. FIG. 8 is a perspective view of the motor unit of this embodiment. FIG. 9 is a schematic diagram of an electric power steering device equipped with the motor unit of this embodiment.

Hereinafter, motors according to embodiments of the present invention will be described with reference to the drawings. It should be noted that the scope of the present invention is not limited to the following embodiments, and can be arbitrarily changed within the scope of the technical idea of the present invention. Also, in the drawings below, in order to make each configuration easier to understand, there are cases where the actual structure and the scale, number, etc. of each structure are different.

Also, in the drawings, an XYZ coordinate system is appropriately shown as a three-dimensional orthogonal coordinate system. In the XYZ coordinate system, the Z-axis direction is parallel to the axial direction of the central axis (rotational axis) J shown in FIG. The X-axis direction is a direction perpendicular to the Z-axis direction and is the horizontal direction in FIG. The Y-axis direction is a direction orthogonal to both the X-axis direction and the Z-axis direction.

Also, in the following description, the positive side in the Z-axis direction (+Z side, one side) is called the "upper side", and the negative side in the Z-axis direction (-Z side, the other side) is called the "lower side." call. Note that the upper side and the lower side are names used merely for explanation, and do not limit the actual positional relationship and direction. Further, unless otherwise specified, the direction parallel to the central axis J (the Z-axis direction) is simply referred to as the "axial direction", the radial direction about the central axis J is simply referred to as the "radial direction", and the central axis J , that is, the circumference of the central axis J is simply referred to as the "circumferential direction". Furthermore, in the following description, "planar view" means a state viewed from the axial direction.

FIG. 1 is a cross-sectional view along the axial direction of the motor unit 1 of this embodiment. 2 is an enlarged view of a main part of FIG. 1. FIG. FIG. 3 is a cross-sectional view similar to FIG. 1, showing the positional relationship between a recess 74 and an electronic component 67, which will be described later. FIG. 4 is a plan view of the later-described cover 70 viewed from the axial direction. FIG. 5 is a cross-sectional view similar to FIG. 1 showing a first modification of the present embodiment. FIG. 6 is a cross-sectional view similar to FIG. 2 showing a second modification of the present embodiment. FIG. 7 is a plan view similar to FIG. 4 showing a third modification of this embodiment. FIG. 8 is a perspective view of the motor unit 1 of this embodiment. FIG. 9 is a schematic diagram of an electric power steering device 101 equipped with the motor unit 1 of this embodiment.

<Motor unit>
As shown in FIGS. 1 and 8 , the motor unit 1 includes a motor section (motor body) 3 , a control section 5 and a cover 70 .
The motor section 3 has a rotor 20 that rotates around a central axis J that extends in the vertical direction. The control section 5 is positioned above the motor section 3 . The controller 5 controls rotation of the rotor 20 . The cover 70 surrounds the control unit 5 from the radially outer side and upper side.

<Motor part>
The motor section 3 includes a motor housing 11 , a rotor 20 , a stator 30 , an upper bearing 24 and a lower bearing 25 .

<Motor housing>
The motor housing 11 has a cylindrical shape that opens upward (+Z side). The motor housing 11 accommodates each member of the motor section 3 . The motor housing 11 of this embodiment includes a housing body 11 a and a bearing holder (heat sink) 40 .

<Housing body>
The housing body 11 a has a tubular portion 14 , a bottom portion 13 and a lower bearing holding portion 18 . The housing body 11a is made of, for example, an aluminum alloy. The housing body 11a is, for example, a single member.
The tubular portion 14 has a tubular shape surrounding the radially outer side of the stator 30 . In this embodiment, the tubular portion 14 is, for example, cylindrical. The tubular portion 14 is connected to the lower end portion of the peripheral wall portion 43 of the bearing holder 40 at the upper end portion 14a. A stator 30 is fixed to the inner surface of the cylindrical portion 14 .

The bottom portion 13 is provided at the lower (−Z side) end portion of the cylindrical portion 14 . The bottom portion 13 is provided with an axial through hole 13a that penetrates the bottom portion 13 in the axial direction (Z-axis direction). The lower bearing holding portion 18 is provided on the upper (+Z side) surface of the bottom portion 13 . The lower bearing holding portion 18 holds the lower bearing 25 . An upper bearing holding portion 47 that holds the upper bearing 24 is provided in the bearing holder 40 .

<Rotor>
The rotor 20 has a shaft 21 , a rotor core 22 and rotor magnets 23 .
The shaft 21 has a central axis J extending in the vertical direction (Z-axis direction) as its axis. The shaft 21 is rotatably supported around the central axis J by a lower bearing 25 and an upper bearing 24 . The lower (-Z side) end of the shaft 21 protrudes to the outside (downward) of the motor housing 11 through the shaft through-hole 13a. For example, a coupler (not shown) for connecting to an output target is press-fitted into the lower end of the shaft 21 .

A sensor magnet 63 is attached to the upper end of the shaft 21 via an attachment member 62 . For example, the sensor magnet 63 may be attached directly to the tip of the shaft 21 with an adhesive or the like.

Rotor core 22 is fixed to shaft 21 . The rotor core 22 surrounds the shaft 21 in the circumferential direction. A rotor magnet 23 is fixed to the rotor core 22 . More specifically, the rotor magnet 23 is fixed to the outer surface of the rotor core 22 along the circumferential direction. Rotor core 22 and rotor magnet 23 rotate together with shaft 21 .

<Stator>
The stator 30 surrounds the radially outer side of the rotor 20 . The stator 30 has a stator core 31 , a bobbin 32 and a coil (winding) 33 .
The bobbin 32 is made of an insulating material. Bobbin 32 covers at least part of stator core 31 . The coil 33 excites the stator core 31 when the motor unit 1 is driven. The coil 33 is configured by winding a coil wire 33a. The coil wire 33 a is wound through the bobbin 32 . An end of the coil wire 33a is drawn upward. The drawn coil wire 33a is connected to a motor terminal 53, which will be described later. Motor terminals 53 are connected to board terminals 51 extending from board 66 . The coil 33 of the stator 30 is connected to the board 66 via the board terminals 51 and the motor terminals 53 .

<Upper bearing and lower bearing>
Upper bearing 24 rotatably supports the upper end of shaft 21 . The upper bearing 24 is positioned above the stator 30 (+Z side). The upper bearing 24 is held by the upper bearing holder 47 of the bearing holder 40 .
A lower bearing 25 rotatably supports the lower end of the shaft 21 . The lower bearing 25 is positioned below the stator 30 (-Z side). The lower bearing 25 is held by the lower bearing holding portion 18 of the motor housing 11 .

In this embodiment, upper bearing 24 and lower bearing 25 are ball bearings. However, the types of the upper bearing 24 and the lower bearing 25 are not particularly limited, and other types of bearings may be used.

<Bearing holder (heat sink)>
The bearing holder 40 is located above the stator 30 (+Z side). A bearing holder 40 holds the upper bearing 24 . The shape of the bearing holder 40 in plan view is, for example, a circular shape concentric with the central axis J. As shown in FIG. The bearing holder 40 is made of, for example, the same aluminum alloy as the housing body 11a. The bearing holder 40 is, for example, a single member. The bearing holder 40 is sandwiched between the housing body 11 a and the cover 70 . The bearing holder 40 is arranged between the motor section 3 and the control section 5 .

The bearing holder 40 has an upper wall portion 41 , a collar portion 42 and a peripheral wall portion 43 .
The upper wall portion 41 has a flat plate shape perpendicular to the axial direction. The upper wall portion 41 is arranged at the upper end portion 14a of the cylindrical portion 14 of the housing body 11a. The upper wall portion 41 is provided with an upper through-hole 45 penetrating in the axial direction (Z-axis direction). The upper through-hole 45 is positioned substantially in the center of the bearing holder 40 in plan view. The upper wall portion 41 is provided with a terminal passing hole 49 through which the motor terminal 53 extending from the stator 30 is passed along the axial direction.

The collar portion 42 is provided on the lower surface side (−Z side) of the upper wall portion 41 . The collar portion 42 protrudes downward from the peripheral portion of the upper through hole 45 in the upper wall portion 41 . The collar portion 42 has a cylindrical shape coaxial with the upper through hole 45 .

An upper inner peripheral surface 42 a having the same diameter as the upper through hole 45 is provided on the upper portion of the collar portion 42 . A lower inner peripheral surface 42b having a larger diameter than the upper inner peripheral surface 42a is provided at the lower portion of the collar portion 42 . A step surface 42c is provided between the upper inner peripheral surface 42a and the lower inner peripheral surface 42b. The step surface 42c is a plane perpendicular to the axial direction.

A lower portion of the collar portion 42 constitutes an upper bearing holding portion 47 that holds the upper bearing 24 . The upper bearing holding portion 47 holds the upper bearing 24 on the inner peripheral side of the lower inner peripheral surface 42b and below the stepped surface 42c. A sensor magnet 63 is arranged in a space above the upper bearing 24 on the inner peripheral side of the upper inner peripheral surface 42a. A lower surface 66 a of the substrate 66 is arranged above the sensor magnet 63 . A rotation sensor 61 is mounted on a portion of the lower surface 66 a of the substrate 66 that faces the sensor magnet 63 .

The peripheral wall portion 43 protrudes upward from the outer peripheral edge portion of the upper wall portion 41 . The peripheral wall portion 43 has a cylindrical (annular) shape surrounding the radially outer side of the substrate 66 . In this embodiment, the peripheral wall portion 43 has, for example, a cylindrical shape that continues above the tubular portion 14 of the housing body 11a. The peripheral wall portion 43 is connected to the upper end portion 14a of the cylindrical portion 14 at its lower end portion.

Below the lower end portion of the peripheral wall portion 43, an insertion wall 43a is provided that protrudes downward. The insertion wall 43 a is annularly provided over the entire circumference of the lower end of the peripheral wall portion 43 . The insertion wall 43 a is provided at the inner peripheral side of the lower end of the peripheral wall portion 43 . The insertion wall 43a is fitted into the inner peripheral side of the upper end portion 14a of the tubular portion 14 of the housing body 11a, and the outer peripheral surface thereof is brought into contact with the inner peripheral surface of the upper end portion 14a.

A stepped surface 43b is provided at the lower end of the peripheral wall portion 43 on the outer peripheral side of the insertion wall 43a. The step surface 43b is a plane perpendicular to the axial direction. The step surface 43b contacts the upper surface 14b of the upper end portion 14a of the cylindrical portion 14. As shown in FIG.
The outer peripheral surface of the insertion wall 43a, the inner peripheral surface of the cylindrical portion 14, and the stepped surface 43b and the upper surface 14b are adhered to each other with an adhesive. Thereby, the bearing holder 40 and the housing body 11a are coupled to each other.

Between the upper surface 40a of the upper wall portion 41 of the bearing holder 40 and the lower surface 66a of the substrate 66, a heat dissipating material (not shown) such as heat dissipating grease is provided. The heat dissipating material transfers heat generated in the substrate 66 and mounted components mounted on the substrate 66 to the bearing holder 40 . The bearing holder 40 radiates heat transmitted through the heat radiating material to the outside. That is, the bearing holder 40 of the present embodiment functions as a heat sink for the substrate 66 and thus the controller 5 . The bearing holder 40 may be referred to as a heat sink 40 hereinafter.

The substrate 66 is not limited to being in surface contact with the heat sink 40, and may be floated on the heat sink 40 via spacers. The substrate 66 is not limited to the configuration in which the electronic components 67 are mounted on the upper surface 66b, and the electronic components 67 may be mounted on the lower surface 66a.
Also, the upper through-hole 45 may be closed with a lid. The lid preferably constitutes a flat upper surface 40 a together with the upper wall portion 41 of the heat sink 40 . The lid body is preferably brought into contact with the lower surface 66a of the substrate 66 via a heat radiating material.
Furthermore, a configuration in which the heat sink 40 is not provided may be used. That is, the substrate 66 may be arranged on a member (made of resin or the like) different from the heat sink 40 and the housing main body 11a.

<Control unit>
As shown in FIG. 1, the controller 5 has a substrate 66 . The substrate 66 has, for example, a rectangular shape in plan view (see FIG. 4). The board 66 has a plurality of electronic components 67 mounted on the board body. The electronic parts 67 are the rotation sensor 61, an electrolytic capacitor, a choke coil, and the like. The number of substrates 66 used in the motor unit 1 is not limited to one, and may be plural.

The board 66 controls the motor unit 1 . The substrate 66 is connected to the lower end (base end 51a) of the substrate terminal 51 extending in the axial direction. The proximal end 51a is inserted into a through hole formed in the substrate 66 and joined to the substrate by soldering or the like. A terminal to be joined to the base end 51a may be surface-mounted on the upper surface 66b, and the terminal and the base end 51a may be joined by soldering or the like. The board terminal 51 extends axially upward from the base end 51a. The board terminal 51 extends linearly from the proximal end 51a to the distal end 51b. Hereinafter, a portion of the substrate terminal 51 that extends linearly from the proximal end 51a to the distal end 51b is referred to as a first linear portion 51c.

A motor terminal 53 is connected to the board terminal 51 . The motor terminal 53 is connected to the coil 33 of the stator 30 at a base end extension extending radially inward (toward the central axis J) from a base end 53 a (lower end). The motor terminal 53 extends axially upward from the base end 53a. The motor terminal 53 extends linearly from the proximal end 53a to the distal end 53b. Hereinafter, a portion of the motor terminal 53 that extends linearly from the proximal end 53a to the distal end 53b is referred to as a second linear portion 53c.

The first straight portion 51c of the board terminal 51 and the second straight portion 53c of the motor terminal 53 are connected to each other. The board 66 is connected to the motor section 3 via the board terminals 51 and the motor terminals 53 .

It is preferable to mount the heating element of the electronic component 67 on the substrate 66 in contact with the bearing holder 40 . As a result, the heat generated from the heating element is efficiently radiated through the bearing holder 40 . In this specification, the heating element means an element among the electronic components 67 mounted on the substrate 66 that emits heat and reaches a high temperature. Examples of heat generating elements include field effect transistors, capacitors, driver integrated circuits for driving field effect transistors, power supply integrated circuits, switching elements, and semiconductor switching elements. The type of the heating element is not limited as long as it is an element that reaches a high temperature.

The substrate 66 is arranged on the upper side (+Z side) of the bearing holder 40 . The plate surface direction of the substrate 66 (the direction along the upper and lower surfaces 66a and 66b) is perpendicular to the axial direction. That is, the substrate 66 is arranged along the direction perpendicular to the central axis J. As shown in FIG. The thickness direction of the substrate 66 is parallel to the axial direction.
The lower surface 66a of the substrate 66 and the upper surface 40a of the bearing holder 40 are in contact with each other. That is, the substrate 66 contacts the upper surface 40a of the motor section 3. As shown in FIG. A space between the lower surface 66a of the substrate 66 and the upper surface 40a of the bearing holder 40 is filled with heat dissipating grease or the like.

In this specification, two members “contact” means that if the positions of the two members are uniquely determined in the direction of contact, another member prepared separately is “contacted through”. It is a concept that includes the case of "doing". Therefore, the substrate 66 contacts the upper surface 40a of the motor section 3. As shown in FIG. "Other members" include those with fluidity such as thermal grease.

A rotation sensor 61 is mounted on the lower surface 66 a of the substrate 66 . The rotation sensor 61 overlaps the upper through hole 45 when viewed from the axial direction. The rotation sensor 61 overlaps the sensor magnet 63 when viewed from the axial direction. The rotation sensor 61 detects rotation of the sensor magnet 63 . In this embodiment, the rotation sensor 61 is a magnetoresistive element. The rotation sensor 61 may be, for example, a Hall element.

<Cover>
As shown in FIG. 1, the cover 70 is positioned above the motor section 3 (+Z side). The cover 70 has a bottomed cylindrical shape that opens downward (−Z side). The cover 70 covers the control section 5 arranged at the upper end of the motor section 3 . The cover 70 provides a board accommodation space K2 at the upper end of the motor section 3 .

The cover 70 has a cover peripheral wall portion 71 and a flat plate portion 72 .
The cover peripheral wall portion 71 has a tubular (annular) shape surrounding the radially outer side of the control portion 5 . In this embodiment, the cover peripheral wall portion 71 has, for example, a cylindrical shape that continues above the peripheral wall portion 43 of the bearing holder 40 . The cover peripheral wall portion 71 is connected to the upper end portion of the peripheral wall portion 43 at its lower end portion.

Below the cover peripheral wall portion 71, an insertion wall 71a is provided that protrudes downward along the axial direction. The insertion wall 71 a is annularly provided over the entire circumference of the lower end of the cover peripheral wall portion 71 . The insertion wall 71 a is provided biased toward the inner peripheral side of the lower end of the cover peripheral wall portion 71 . The insertion wall 71 a is fitted into the inner peripheral side of the peripheral wall portion 43 of the bearing holder 40 and brings the outer peripheral surface thereof into contact with the inner peripheral surface of the peripheral wall portion 43 .

A stepped surface 71b is provided at the lower end of the cover peripheral wall portion 71 on the outer peripheral side of the insertion wall 71a. The step surface 71b is a plane perpendicular to the axial direction. The step surface 71 b contacts the upper surface 14 b of the peripheral wall portion 43 of the bearing holder 40 .
The outer peripheral surface of the insertion wall 71a, the inner peripheral surface of the peripheral wall portion 43, and the stepped surface 71b and the upper surface 14b are adhered to each other with an adhesive. Thereby, the cover 70 and the bearing holder 40 are joined together. That is, the cover 70 and the upper portion of the motor housing 11 are coupled to each other, and the cover 70 is fixed to the motor section 3 . The cover 70 of this embodiment is attached to the heat sink 40 along the axial direction.

An internal space surrounded by the cover 70 and the bearing holder 40 is defined as a board accommodation space K2. A substrate 66 is accommodated in the substrate accommodation space K2. Note that the cover 70 may be regarded as a configuration of the control section 5 . Reference numeral 71c in the drawing indicates the outer peripheral surface of the cover peripheral wall portion 71. As shown in FIG.

The flat plate portion 72 is provided at the upper (+Z side) end portion of the cover peripheral wall portion 71 . The flat plate portion 72 covers the upper opening of the cover peripheral wall portion 71 . The flat plate portion 72 covers one axial side (upper side) of the board accommodation space K2. The flat plate portion 72 faces the substrate 66 in the axial direction. The axial height of the flat plate portion 72 is determined according to the axial height of the electrical components mounted on the board 66 . For example, in the substrate 66 of the embodiment, the electrolytic capacitor arranged near the center in plan view is the tallest, and the height of the electrolytic capacitor determines the height of the flat plate portion 72 and thus the cover 70 .

<Stepped part, concave part>
1, 2 and 4, the flat plate portion 72 has a circular shape that substantially overlaps the entire motor housing 11 when viewed in the axial direction. A portion of the overall shape of the flat plate portion 72 viewed in the axial direction is a stepped portion 73 arranged on the other side (lower side) in the axial direction than the remaining flat plate body portion 72a.
The flat plate portion 72 has a flat plate body portion 72a and a concave portion 74 recessed downward with respect to the flat plate body portion 72a. Reference numeral 72b in the drawing indicates the upper surface of the flat plate body portion 72a. The recessed portion 74 is recessed from the cover outer surface (upper surface 72b) on one side in the axial direction of the flat plate body portion 72a toward the board accommodation space K2 (the other side in the axial direction).

The recess 74 has a cylindrical shape with a bottom and includes a bottom portion 75 and a peripheral wall portion 76 . A bottom portion 75 on the other side in the axial direction of the recessed portion 74 is a stepped portion 73 . An opening 74a is provided at the upper end of the recess 74 to open the recess space K1 upward. The space inside the recessed portion 74 is a recessed space K1 that opens toward one side in the axial direction on the cover outer surface (upper surface 72b). The recessed space K<b>1 is a space located above the bottom portion 75 and below the opening 74 a and surrounded by the peripheral wall portion 76 . The concave portion 74 is a portion for power line connection in the motor unit 1 .

Referring to FIG. 3 , the axial height of bottom portion 75 is determined according to the height of some electronic components 67 . A part of the electronic component 67 is a component arranged so that at least a portion thereof overlaps with the bottom portion 75 when viewed from the axial direction. Hereinafter, the electronic component 67 that is higher in the axial direction than the bottom portion 75 is referred to as the first electronic component 67a, and the electronic component 67 that is lower in the axial direction than the bottom portion 75 is referred to as the second electronic component 67b. The second electronic component 67b is a part of the electronic component, and at least partially overlaps with the bottom portion 75 when viewed in the axial direction.

The axial height of the lower end (for example, the lower surface) of the bottom portion 75 is located above the upper end (for example, the upper surface) of the second electronic component 67b. This avoids interference between the bottom portion 75 and the second electronic component 67b. A first electronic component 67a (such as an electrolytic capacitor) having an axial height higher than the lower end of the bottom portion 75 is arranged in a range avoiding the concave portion 74 when viewed in the axial direction.

In the embodiment, the axial height of the flat plate body portion 72a is determined by the first electronic component 67a that is higher in the axial direction than the stepped portion 73 of the cover 70 . In addition, the second electronic component 67b having a lower axial height than the stepped portion 73 is also arranged in a range overlapping with the stepped portion 73 when viewed in the axial direction. In this manner, the substrate accommodation space K2 capable of accommodating the first electronic component 67a having a high axial height is provided, and the second electronic component having a low axial height is also provided in the range overlapping the stepped portion 73 when viewed from the axial direction. By arranging the 67b, it is possible to efficiently suppress the enlargement of the cover 70 and the motor unit 1 by extension.

The recess 74 may have a retraction structure 78 that avoids the second electronic component 67b. The retraction structure 78 is, for example, a structure in which the bottom portion 75 is recessed leaving a portion having a through hole 77, which will be described later, so that the second electronic component 67b can be easily avoided. The retraction structure 78 is, for example, a structure that widens the recessed space K1 until it overlaps with the second electronic component 67b when viewed in the axial direction, and facilitates terminal connection in the recessed space K1.

Referring to FIG. 4, at least part of recess 74 is arranged to avoid substrate 66 when viewed in the axial direction. This increases the range in which the substrate 66 and the stepped portion 73 do not overlap when viewed in the axial direction. That is, the range in which the electronic component 67 on the board 66 is not restricted by the height in the axial direction is widened.

The recessed portion 74 and the stepped portion 73 in FIG. 4 have a shape extending in an arc shape along the circumferential direction when viewed from the axial direction. The recessed portion 74 and the stepped portion 73 extend circumferentially with a constant radial width. A plurality of through-holes 77 are also arranged side by side along the circumferential direction in the stepped portion 73 . The through hole 77 is a hole that allows the substrate terminals 51 and the motor terminals 53 extending in the axial direction to enter the recess 74 (inside the recess space K1). Each through hole 77 is located near the center of the radial width of the stepped portion 73 and penetrates the stepped portion 73 in the axial direction. Hereinafter, the pair of the board terminal 51 and the motor terminal 53 inserted into each through-hole 77 may be referred to as a "terminal pair".

Terminal pairs of the U-phase, V-phase, and W-phase of the motor section 3 are inserted into the respective through holes 77 . The terminal pairs of each phase are arranged side by side along the circumferential direction inside the concave portion 74 . The substrate terminals 51 and the motor terminals 53 arranged in the recessed space K1 from the through holes 77 are connected to each other by the terminals for each phase. This connection work can be performed sequentially while rotating the workpiece (the motor unit 1 in the middle of assembly) held by the robot arm, for example, in the circumferential direction. The radial width of the concave portion 74 is set to a minimum width that allows a tool such as a welding gun for terminal connection work to enter. The concave portion 74 having an arcuate shape when viewed in the axial direction has a small portion overlapping the substrate 66 when viewed in the axial direction, and easily avoids interference with the electronic components 67 on the substrate 66 .

The recessed portion 74' and the stepped portion 73' shown in FIG. 7 have a rectangular shape when viewed from the axial direction. The concave portion 74 ′ and the stepped portion 73 ′ extend with a constant width along one side (one side edge) of the substrate 66 . A plurality of through holes 77 are arranged along one side of the substrate 66 in the step portion 73 ′. In this case, it is easy to arrange the connecting portions between the substrate 66 and the substrate terminals 51 at the ends of the substrate 66 . Moreover, it is easy to form the plurality of substrate terminals 51 in the same shape and to make them common.

<Motor terminals and board terminals>
As shown in FIG. 1, the substrate terminal 51 extends from a proximal end 51a connected to the substrate 66 toward a distal end 51b. The board terminal 51 has a first linear portion 51c extending along the axial direction within a predetermined length range from the tip 51b.
The motor terminal 53 extends from a proximal end 53a connected to the stator 30 toward a distal end 53b. The motor terminal 53 has a second linear portion 53c extending along the axial direction within a predetermined length range from the tip 53b.

The board terminals 51 and the motor terminals 53 are strip-shaped members each extending with a constant width. The widths of the substrate terminals 51 and the motor terminals 53 are, for example, substantially the same. Each of the board terminals 51 and the motor terminals 53 is made of, for example, a copper alloy. Each of the board terminals 51 and the motor terminals 53 is, for example, a single member.
The lower end (base end 51a) of the first straight portion 51c of the board terminal 51 and the lower end (base end 53a) of the second straight portion 53c of the motor terminal 53 overlap the through hole 77 when viewed in the axial direction. Therefore, each straight part 51c, 53c can be inserted into the through hole 77 along the axial direction.

Referring to FIG. 2, straight portions 51c and 53c of substrate terminal 51 and motor terminal 53 are, for example, plate-shaped with the thickness direction directed radially. The straight portions 51c and 53c are inserted into the through holes 77 so as to overlap each other in the radial direction. The through-hole 77 has a rectangular opening cross-section which is large enough to keep the linear portions 51c and 53c in an overlapping state. The inner peripheral surface of the through hole 77 has a linear portion 77a having a constant cross section on one side in the axial direction, and a tapered portion 77b that expands the opening cross section at least in the radial direction toward the other side in the axial direction. By providing a tapered portion 77b on the lower side of the through-hole 77 (on the board accommodation space K2 side), the terminals 51 and 53 are inserted into the through-hole 77 from the other side in the axial direction (on the side of the board 66 and the side of the motor section 3). becomes easier.

The upper side of the through-hole 77 has an open cross-section that allows the linear portions 51c and 53c to be kept in an overlapping state. As a result, the terminals 51 and 53 inserted from the tapered portion 77b are brought closer to each other. Moreover, the tapered portion 77b facilitates assembly even if the ends 51b and 53b of the terminals 51 and 53 are shaken (especially in the thickness direction). That is, the terminals 51 and 53 can be easily inserted into the through holes 77 by the tapered portions 77b.

The cover 70 is attached to the heat sink 40 along the axial direction. At this time, the terminals 51 and 53 can be easily inserted into the through holes 77 inside the cover 70 . In addition, since the opening cross section of the upper side of the through hole 77 is narrowed, welding spatter is less likely to enter the substrate accommodation space K2 than if the through hole 77 were simply a loose hole.

The straight portions 51c and 53c pass through the through holes 77 and enter the concave space K1 from the substrate accommodation space K2. The straight portions 51c, 53c and the terminals 51, 53 are connected to each other by welding, for example, within the concave space K1. Even after the cover 70 is fixed, a tool such as a welding gun can enter the concave space K1 through the opening 74a of the concave portion 74 that opens upward. The linear portions 51c and 53c are sandwiched between the instruments in the overlapping direction while overlapping each other. The straight portions 51c and 53c are connected by welding or the like in a state where they are sandwiched between instruments and pressurized. The terminals 51 and 53 are connected to each other by spot welding, for example. The connection between the terminals 51 and 53 may be made by gas welding, laser welding, or the like other than spot welding, or may be made by soldering or TOX (registered trademark) crimping.

TOX crimping is an example of a press joint. In the TOX caulking, the 51 and 53 in a state of being superimposed on each other are sandwiched between an upper die having a columnar convex portion and a lower die having a concave portion, and press working is performed. As a result, the terminals 51 and 53 are plastically deformed and joined together. TOX crimping is an example of crimping, and since it does not use rivets, it can be easily applied to small parts and has cost advantages.

The configuration is not limited to the configuration in which the terminals 51 and 53 are inserted into one through-hole 77, and a configuration in which the terminals 51 and 53 are inserted into separate through-holes 77 is also possible. In addition, by performing additional processing such as bending at least one of the terminals 51 and 53 entering the concave space K1, or by providing a separate member for connection between the terminals 51 and 53, each terminal 51 , 53 may be connected to each other.

If the motor terminals 53 are directly connected to the substrate 66 through through holes, stress is likely to be applied to the solder due to temperature changes due to the difference in thermal expansion coefficient between the motor terminals 53 and the motor housing 11 . On the other hand, by connecting the terminals 51 and 53 via the extension portions (straight line portions 51c and 53c) of the terminals 51 and 53, the difference in thermal expansion coefficient is absorbed and the stress applied to the solder is suppressed. easy. In this respect, if the extended portions of the terminals 51 and 53 have bent portions, it is possible to effectively suppress the application of stress to the solder.

FIG. 5 shows a motor unit 1' of a modification of this embodiment. The motor unit 1 ′ is particularly different in that instead of the recessed portion 74 , a stepped stepped portion 173 opening radially outward is employed. In addition, the same reference numerals are given to the constituent elements of the same aspect as those of the above-described embodiment, and the explanation thereof will be omitted.

In the cover 170 of the modified example, a portion of the cover peripheral wall portion 71 in the circumferential direction is notched. In the cover 170 of the modified example, the portion of the cover peripheral wall portion 71 where the stepped portion 173 is provided is notched. The stepped portion 173 of the cover 170 is arranged on the other axial side (lower side) than the flat plate body portion 72a. The outer peripheral side (diameter direction outer side) of the stepped portion 173 is open without the cover peripheral wall portion 71 . A standing wall portion 174 is provided along the axial direction between the stepped portion 173 and the flat plate body portion 72a.

In the cover 170, a recessed space K3 is defined as a space overlapping the stepped portion 173 when viewed in the axial direction. The concave space K3 is provided in the axial direction between the upper surface of the stepped portion 173 and the imaginary upper surface 72b' continuous with the upper surface 72b of the flat plate body portion 72a. The periphery of the recessed space K<b>3 is defined by the side surface of the standing wall portion 174 and an imaginary outer peripheral surface 71 c ′ that continues to the outer peripheral surface 71 c of the cover peripheral wall portion 71 .

In the modified example of FIG. 5, similarly to the embodiment, the flat plate portion 72 of the cover 170 covering the substrate housing space K2 is provided with a stepped portion 173 located on the other side in the axial direction of the flat plate body portion 72a. A recessed space K3 is defined in the cover 170 by the stepped portion 173 . The stepped portion 173 is provided with a through hole 77 through which the board terminal 51 and the motor terminal 53 are passed, and the board terminal 51 and the motor terminal 53 that enter the recessed space K3 through the through hole 77 are connected to each other in the recessed space K3. do.

According to this embodiment and modification, even if the terminals 51 and 53 are connected by welding, the spatter generated when the terminals 51 and 53 are welded together is less likely to enter the board accommodation space K2. It becomes more difficult to enter the inside of the motor. In this way, it is possible to prevent foreign matter such as welding spatter from entering the motor.

Also, the connecting portions 55 that connect the terminals 51 and 53 are arranged in the recessed spaces K1 and K3 provided in the covers 70 and 170, respectively. Therefore, the connection portion 55 does not protrude from the outer surface of the cover (upper surface 72b and outer peripheral surface 71c). Therefore, it is possible to suppress an increase in the size of the unit, and to suppress the connection portion 55 from coming into contact with peripheral parts or the body of the operator. Hereinafter, the connection portion 55 may be referred to as a terminal connection portion 55 .

The terminal connections 55 in the embodiments and modifications are welded joints. After the covers 70 and 170 are assembled, the connection operation of the terminal connection portion 55 is performed in the recessed spaces K1 and K3 in the covers 70 and 170 that are open to the outside of the unit. As a result, in addition to the effects described above, it becomes easier to use the welding robot, and it becomes easier to automate the manufacture of the motor unit.

In the embodiment and modification, the terminals 51 and 53 axially extending toward the flat plate portion 72 on the upper side of the covers 70 and 170 are formed in concave spaces K1 and K3 that are open upward on the outer surface of the cover (upper surface 72b). and connect them by overlapping them in the radial direction. As a result, compared to a configuration in which the terminals 51 and 53 extend in the radial direction, the motor unit is prevented from increasing in size in the radial direction.

<Sealing member and cap>
As shown in FIG. 2, in the embodiment, after the terminals 51 and 53 are connected to each other, a sealing member 81 for sealing the terminal connection portion 55 is arranged inside the concave portion 74 . The sealing member 81 is, for example, a potting material, and is filled in the recess 74 after the terminals 51 and 53 are connected to each other. Thereby, the terminal connection portion 55 is sealed.

In addition, a cap 82 is arranged in the opening 74a on one side of the recess 74 in the axial direction to close the opening 74a. The cap 82 is made of resin similar to the cover 70, for example. Sealing member 81 is provided to obtain at least one of waterproof performance and oil-proof performance of terminal connection portion 55 . The cap 82 is provided to protect the terminal connection portion 55 from disturbance such as flying stones.

FIG. 6 shows an example in which an O-ring is provided on the outer circumference of the cap 82. As shown in FIG. By providing the O-ring in the cap 82, it is possible to prevent water and oil from entering the recessed space K1 and the substrate housing space K2. That is, it is easy to ensure waterproof performance and oil-proof performance of the motor unit 1 .
Only one of the sealing member 81 and the cap 82 may be provided according to the required performance of waterproofing, oil-proofing, and disturbance suppression. Also, the cap 82 may be fixed to the recess 74 by laser welding. According to this, it is possible to prevent water and oil from entering the concave space K1 and the substrate accommodation space K2 without providing an O-ring.

Regarding the axial depth of the concave portion 74, if the concave portion 74 is too deep, it becomes difficult to perform terminal connection work (welding work), and if the concave portion 74 is too shallow, the resin (insulating) cover 70 tends to melt. Therefore, the axial depth of recess 74 is determined in consideration of both welding workability and heat resistance of cover 70 .

<Electric power steering device>
Next, an embodiment of a device equipped with the motor unit 1 of this embodiment will be described. In this embodiment, an example in which the motor unit 1 is installed in an electric power steering device 101 will be described. FIG. 9 is a schematic diagram showing the electric power steering device 101 of this embodiment.

An electric power steering device 101 is mounted on a steering mechanism for wheels 102 of an automobile. The electric power steering device 101 of this embodiment is a rack-type power steering device that directly reduces the steering force by the power of the motor unit 1 . The electric power steering device 101 includes a motor unit 1 , a steering shaft 104 and an axle (tie rod) 103 .

Steering shaft 104 transmits input from steering 105 to axle 103 having wheels 102 . The motor unit 1 is attached to the axle 103 . Power of the motor unit 1 is transmitted to the axle 103 via a ball screw (not shown). Since the motor unit 1 employed in the rack-type power steering device 101 is attached to the axle 103 and exposed to the outside, it requires a waterproof structure.

An electric power steering device 101 of this embodiment includes the motor unit 1 of this embodiment. Therefore, it is possible to obtain the electric power steering apparatus 101 having the same effect as that of the present embodiment.
Here, the power steering device 101 is given as an example of the usage of the motor unit 1 of this embodiment, but the usage of the motor unit 1 is not limited.

In this embodiment, the substrate terminals 51 and the motor terminals 53 that enter the recessed space K1 through the through holes 77 of the stepped portion 73 are connected to each other within the recessed space K1. Therefore, even if the terminals 51 and 53 are connected to each other by welding, it is difficult for spatters generated when the terminals 51 and 53 are welded together to enter the board accommodation space K2, and more difficultly to enter the motor. In this way, it is possible to prevent foreign matter such as welding spatter from entering the motor.
Further, since the connection portion 55 between the terminals 51 and 53 is arranged in the recessed space K1 provided in the cover 70, the connection portion 55 does not protrude from the outer surface of the cover. Therefore, it is possible to prevent the unit from increasing in size and to prevent the terminal connection portion 55 from coming into contact with peripheral parts or the body of the operator.

In the motor unit 1 of the present embodiment, a sealing member 81 that seals the connecting portions 55 of the substrate terminals 51 and the motor terminals 53 is arranged in the recess 74 .
According to this configuration, since the connection portion 55 between the terminals 51 and 53 is sealed within the recess 74, the connection portion 55 between the terminals 51 and 53 is prevented from coming into contact with peripheral components and the body of the operator. At the same time, the connection portion 55 between the terminals 51 and 53 can be protected.

In the motor unit 1 of the present embodiment, the recess 74 is provided with a cap 82 that closes the opening 74a on one side in the axial direction.
According to this configuration, since the opening 74a of the recess 74 is closed, the connection portion 55 between the terminals 51 and 53 is hidden in the recess 74, and the connection portion 55 between the terminals 51 and 53 is not accessible to peripheral parts or workers. Contact with the body can be suppressed, and the connecting portion 55 between the terminals 51 and 53 can be protected.

In the present embodiment, the first straight portion 51c and the second straight portion 53c are passed through the through hole 77 while overlapping each other.
According to this configuration, the first straight portion 51c on the tip 51b side of the board terminal 51 and the second straight portion 53c on the tip 53b side of the motor terminal 53 are passed through the through-hole 77 while overlapping each other. As a result, the terminals 51 and 53 are guided into the recessed space K1 in a state of being superimposed on each other, so that the work of connecting the terminals 51 and 53 can be facilitated.
Further, if the cover 70 is detachable in the axial direction with respect to the motor housing 11, the cover 70 can be detached with the straight portions 51c and 53c overlapping each other, facilitating assembly, disassembly, and maintenance of the unit. can be

In the motor unit 1 of this embodiment, the board terminal 51 extends along the axial direction from the proximal end 51a to the distal end 51b.
According to this configuration, the board terminal 51 extends from the base end 51a in the axial direction and reaches the through hole 77 without being bent. can be done. In addition, it is possible to easily ensure the accuracy of the shape of the board terminal 51 .

In the motor unit 1 of the present embodiment, the electronic component 67 mounted on the upper surface 66b is arranged to avoid the stepped portion 73 when viewed in the axial direction, and the height in the axial direction is the end of the stepped portion 73 on the other side in the axial direction. It has a first electronic component 67a that is higher than the
According to this configuration, the tall first electronic component 67a is arranged to avoid the stepped portion 73 when viewed in the axial direction. That is, the first electronic component 67a is arranged without overlapping the stepped portion 73 when viewed in the axial direction. Therefore, it is possible to efficiently suppress the increase in size of the cover 70 and thus the unit.

In the motor unit 1 of the present embodiment, the electronic component 67 mounted on the upper surface 66b is arranged such that at least a portion of the electronic component 67 overlaps the stepped portion 73 when viewed in the axial direction, and the axial height of the stepped portion 73 is It has a second electronic component 67b that is lower than the other end.
According to this configuration, the second electronic component 67b, which is short in height, is arranged so as to overlap the stepped portion 73 when viewed from the axial direction. It can be made compact in the radial direction.

In the motor unit 1 of the present embodiment, at least part of the stepped portion 73 is arranged to avoid the substrate 66 when viewed from the axial direction.
According to this configuration, since the range of the board 66 that does not overlap with the stepped portion 73 when viewed in the axial direction increases, the range of the electronic component 67 that is not restricted by the height in the axial direction expands, and the electronic component 67 can be arranged freely. can be enhanced.

In the motor unit 1 of the present embodiment, a plurality of through holes 77 are arranged in the circumferential direction around the rotation shaft in the stepped portion 73 when viewed from the axial direction.
According to this configuration, a plurality of through-holes 77 are arranged side by side in the circumferential direction in the stepped portion 73 provided in the cover 70 , and the substrate terminals 51 and the motor terminals 53 are passed through the plurality of through-holes 77 , respectively. Since the terminals 51 and 53 are connected, when connecting the terminals 51 and 53 to each other, the plurality of connection operations can be sequentially performed while rotating the workpiece, and the terminal connection process can be simplified. For example, in the case of a three-phase motor, the terminals of the U, V, and W phases are arranged in the circumferential direction, and these connection work can be easily performed.

In the motor unit 1 of the present embodiment, the stepped portion 73 extends in an arc shape along the circumferential direction around the rotation shaft when viewed from the axial direction.
According to this configuration, a plurality of through holes 77 arranged in the circumferential direction are arranged in the arc-shaped stepped portion 73 extending in the circumferential direction around the center of the rotation shaft. It is possible to narrow the range in which the electronic component 67 is restricted by the height in the axial direction.

In the motor unit 1 of this embodiment, the inner peripheral surface of the through hole 77 has a tapered portion 77b that enlarges the through hole 77 toward the other side in the axial direction.
With this configuration, it is easy to insert the terminals 51 and 53 into the through hole 77 from the other side in the axial direction. That is, the terminals 51 and 53 can be easily inserted into the through hole 77 from the substrate 66 side and the motor section 3 side. Therefore, the work of assembling the unit can be facilitated.
Further, by narrowing one side of the through hole 77 in the axial direction, the following effects can be obtained. That is, the inserted terminals 51 and 53 can be brought closer to each other than when the through hole 77 is simply enlarged. In addition, it is possible to make it difficult for foreign matter such as welding spatter to enter the through hole 77 .

In the motor unit 1 of this embodiment, the connecting portions 55 of the board terminals 51 and the motor terminals 53 are welded joints.
If a welding robot is used for automating the manufacturing of the unit, the weld points are preferably external to the housing. Therefore, arranging the welded joint between the terminals 51 and 53 in the concave space K1 opened to the outside of the cover 70 is suitable for automating the manufacturing of the unit.
In addition, the configuration of the present application is also suitable in that welding spatter does not easily enter the board accommodation space K2 or the inside of the motor.

The embodiments and modifications of the present invention have been described above, but each configuration and combination thereof in the embodiments are examples, and additions, omissions, replacements, and modifications of configurations can be made without departing from the scope of the present invention. Other changes are possible. Moreover, the present invention is not limited by the embodiments.

DESCRIPTION OF SYMBOLS 1, 1'... Motor unit 3... Motor part 5... Control part 11... Motor housing (housing) 20... Rotor 30... Stator 33... Coil (winding) 51... Board terminal 51a... Base end 51b front end 51c first straight portion 53 motor terminal 53a base end 53b front end 53c second straight portion 55 connecting portion 66 substrate 66b upper surface (one axial side) surface), 67... Electronic component, 67a... First electronic component, 67b... Second electronic component, 70, 170... Cover, 72... Flat plate portion, 72a... Flat plate body portion, 72b... Upper surface (cover outer surface), 73, 73', 173... stepped portion, 74, 74'... concave portion, 74a... opening, 75... bottom portion, 77... through hole, 77a... straight portion, 77b... tapered portion, 81... sealing member, 82... cap, K1, K3... Recessed space, K2... Substrate housing space, J... Central axis (rotating axis)

Claims (13)

a motor section having a rotor and a stator including motor terminals;
a housing that accommodates the motor unit;
a control unit positioned on one side in the axial direction along the rotation axis of the motor unit;
The control unit includes a board connected to the motor terminal via a board terminal, and a cover surrounding a board accommodation space accommodating the board together with the housing,
the cover includes a flat plate portion covering one axial side of the substrate housing space,
The flat plate portion includes a flat plate body portion and a stepped portion located on the other side in the axial direction of the flat plate body portion,
The stepped portion is provided with a through hole penetrating in the axial direction,
the board terminal and the motor terminal are inserted into the through hole and connected to each other in a recessed space surrounded by the stepped portion;
motor unit. The flat plate portion has a recess recessed from the outer surface of the cover on one side in the axial direction toward the substrate housing space,
The recess has a bottom portion on the other side in the axial direction as the stepped portion, and provides the recessed space that opens toward the one side in the axial direction on the outer surface of the cover.
The motor unit according to claim 1. A sealing member is disposed in the recess for sealing the connecting portion between the substrate terminal and the motor terminal.
The motor unit according to claim 2. A cap that closes an opening on one side in the axial direction is disposed in the recess,
A motor unit according to claim 2 or 3. The stator has windings connected to the motor terminals,
The substrate terminal has a proximal end connected to the substrate, and a first straight line extending from the proximal end toward the distal end, provided within a predetermined length range from the distal end, and extending along the axial direction. and
The motor terminal has a base end connected to the winding, and extends from the base end toward the tip. and a two-straight line,
The first straight portion and the second straight portion are passed through the through hole while overlapping each other.
A motor unit according to any one of claims 1 to 4. the substrate terminal extends along the axial direction from the proximal end to the distal end;
A motor unit according to claim 5. The electronic component mounted on the surface on one side in the axial direction of the substrate,
a first electronic component arranged avoiding the stepped portion when viewed from the axial direction, and having a height in the axial direction higher than the end of the stepped portion on the other side in the axial direction;
A motor unit according to any one of claims 1 to 6. The electronic component mounted on the surface on one side in the axial direction of the substrate,
a second electronic component disposed so as to at least partially overlap with the stepped portion when viewed from the axial direction, and having a height in the axial direction lower than an end of the stepped portion on the other axial side;
A motor unit according to claim 7. At least part of the stepped portion is arranged to avoid the substrate when viewed from the axial direction.
A motor unit according to any one of claims 1 to 8. When viewed from the axial direction, a plurality of the through-holes are arranged in the stepped portion in a circumferential direction around the center of the rotation shaft.
A motor unit according to any one of claims 1 to 9. When viewed from the axial direction, the stepped portion extends in an arc shape along the circumferential direction of the center of the rotation shaft.
A motor unit according to claim 10. The inner peripheral surface of the through hole has a tapered portion that enlarges the through hole toward the other side in the axial direction,
A motor unit according to any one of claims 1 to 11. the connection between the board terminal and the motor terminal is a welded joint;
A motor unit according to any one of claims 1 to 12.

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