JP2019068611A - Motor and sensor attachment structure - Google Patents

Abstract

To provide a motor which achieves a reduction of manufacturing costs and improvement of assembly workability by reducing the number of components, and to provide a sensor attachment structure.SOLUTION: One of a motor case 20 and a sensor cover has an engagement hole and the other has an engagement claw 36 which engages with a periphery of the engagement hole. The sensor cover has an arm part 37a extending from a peripheral wall 35 to a radial outer side. One of a tip of the arm part 37a and the motor case 20 has a protrusion part 37b protruding in an axial direction, and the other has a fitting hole 29 in which the protrusion part 37b is fitted. The arm part 37a elastically deforms through fitting of the protrusion part 37b and the fitting hole 29 and biases the sensor cover in the axial direction that is a direction away from the motor case 20.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a motor provided with a sensor that detects the rotational position of a rotor. The present invention also relates to a sensor mounting structure for attaching a sensor for detecting a predetermined characteristic of a main body to the main body.

  A conventional motor is disclosed in Patent Document 1. The motor includes a rotor having an axially extending shaft, a stator radially opposed to the rotor, and a motor case accommodating the rotor and the stator. Further, the motor case is cylindrical, and the upper portion of the motor case is covered with the upper surface portion (bottom portion). Further, a through hole is formed in the upper surface portion. The upper end portion of the shaft protrudes to the outside of the motor case through the through hole.

  A sensor for detecting the rotational position of the rotor is provided above the motor case. The sensor has a pair of opposing elements, one of which is attached to the upper end of the shaft and the other of which is attached to the sensor cover (sensor housing).

  The sensor cover is cylindrical, and a pair of fixing pieces extending radially outward is provided on the peripheral wall. A positioning hole is provided in the fixing piece, and a bolt hole is provided in the upper surface portion of the motor case. A bolt is inserted into the positioning hole and the bolt hole, and the bolt and a nut disposed inside the motor case are screwed together. Thereby, the sensor cover and the motor case are fastened and fixed.

JP, 2009-177968, A

  However, according to the above-mentioned conventional motor, there is a problem that the number of parts is increased and the manufacturing cost is increased and the assembling workability is lowered by using the bolt and the nut.

  In addition, in the sensor mounting structure in which a sensor for detecting a predetermined characteristic of the main body portion is attached to the main body portion, the number of parts is increased to increase the manufacturing cost and assembly workability is obtained when bolts and nuts are used as described above. There was a problem of falling.

  An object of the present invention is to provide a motor and a sensor mounting structure capable of reducing the number of parts to reduce the manufacturing cost and improving the assembling workability.

  An exemplary motor according to the present invention detects a rotor having an axially extending shaft, a stator radially opposed to the rotor, a motor case accommodating the rotor and the stator, and a rotational position of the rotor. A sensor, and a sensor cover that houses the sensor and is attached to one end of the motor case in the axial direction, one of the motor case and the sensor cover has an engagement hole, and the other has the engagement hole The sensor cover has an arm portion extending radially outward from the peripheral wall, and one of the tip of the arm portion and the motor case projects a protruding portion in the axial direction And the other has a fitting hole into which the protrusion is fitted, and the arm portion is elastically deformed by the fitting between the protrusion and the fitting hole, and the sensor cover is in the axial direction. Biases in a direction away from the motor case.

  Further, an exemplary sensor mounting structure of the present invention is a sensor mounting structure in which a sensor for detecting a predetermined characteristic of a main body portion is attached to the main body portion, a case covering the main body portion, and the case housing the sensor A sensor cover mounted on the installation surface of the sensor, and one of the case and the sensor cover has an engagement hole, and the other has an engagement claw inserted into the engagement hole; An arm portion extending radially outward from the peripheral wall, one of the tip of the arm portion and the case has an axially protruding projection, and the other has a fitting hole into which the projection is fitted The arm portion is elastically deformed by the fitting of the projection and the fitting hole, and biases the sensor cover away from the installation surface.

  According to the present invention, it is possible to provide a motor and a sensor mounting structure capable of reducing the number of parts to reduce the manufacturing cost and improving the assembly workability.

FIG. 1 is a perspective view of a motor according to a first embodiment of the present invention. FIG. 2 is a schematic longitudinal sectional view of a motor according to the first embodiment of the present invention. FIG. 3 is an exploded perspective view of the motor according to the first embodiment of the present invention. FIG. 4 is a perspective view showing the sensor cover of the motor according to the first embodiment of the present invention from below. FIG. 5 is a top view of the motor case of the motor according to the first embodiment of the present invention. FIG. 6 is a top view showing the engagement hole of the motor according to the first embodiment of the present invention in an enlarged manner. FIG. 7 is an enlarged sectional view showing a part of the motor case and the sensor cover of the motor according to the first embodiment of the present invention. FIG. 8 is a bottom view of the mounting board of the motor according to the first embodiment of the present invention. FIG. 9 is a cross-sectional view taken along the line A-A in FIG. FIG. 10 is a cross-sectional view showing a state before the mounting substrate is fixed to the sensor cover of the motor according to the first embodiment of the present invention. FIG. 11 is a top view of a motor case of a motor according to a second embodiment of the present invention. FIG. 12 is a perspective view of a sensor cover of a motor according to a second embodiment of the present invention. FIG. 13 is a top view of a motor case of a motor according to a third embodiment of the present invention. FIG. 14 is a top view of a motor case of a motor according to a fourth embodiment of the present invention. FIG. 15 is a cross-sectional view showing a mounting structure of a sensor cover and a mounting board of a motor according to a fifth embodiment of the present invention.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. In this specification, the upper side in the central axis direction of the motor is referred to as “upper side”, and the lower side is referred to as “lower side”. Note that the vertical direction does not indicate the positional relationship or direction when it is incorporated into an actual device. In addition, a direction parallel to or substantially parallel to the central axis is referred to as “axial direction”, a radial direction centered on the central axis is simply referred to as “radial direction”, and a circumferential direction centered on the central axis is “circumferential direction”. I assume.

First Embodiment
(1. Overall configuration of motor)
A motor according to an exemplary embodiment of the invention will now be described. 1 and 2 show a perspective view and a schematic longitudinal sectional view of a motor 10 according to the first embodiment. The motor 10 is provided with a motor case 20 for housing the stator 22 and the rotor 23.

  The motor case 20 is made of metal and has a cylindrical body portion 20b and an upper surface portion 20a covering the upper surface of the body portion. Further, the lower surface of the body portion 20 b is open and covered by the flange portion 40.

  The stator 22 is annular, and is fixed to the inner peripheral surface of the body 20b. The stator 22 also includes a stator core 22a made of laminated steel plates, and a coil 22b wound around the stator core 22a via an insulating member.

  The rotor 23 is disposed to face the radially inner side of the stator 22. The rotor 23 is cylindrical and includes a magnet. The shaft 24 is fixed to the center of the rotor 23. The rotor 23 is fixed to the shaft 24. The rotor 23 circumferentially surrounds the shaft 24.

  The shaft 24 is a columnar member extending along the central axis C. The shaft 24 is rotatably supported about the central axis C by the upper bearing 25a and the lower bearing 25b.

  The upper bearing 25 a is disposed above the rotor 23. The upper bearing 25a is held at the center of the upper surface portion 20a by an annular upper holding portion 20c projecting downward from the inner surface.

  The lower bearing 25 b is disposed below the rotor 23. The lower bearing 25 b is held at the center of the flange portion 40 by the lower holding portion 40 a disposed on the inner surface.

  Further, an upper surface through hole 21 is formed at the center of the upper surface portion 20a. The upper end portion of the shaft 24 protrudes above the upper surface portion 20 a via the upper surface through hole 21. The sensor magnet unit 26 is fixed to the upper end portion of the shaft 24, and the sensor magnet unit 26 rotates with the shaft 24 by the drive of the motor 10.

  A sensor cover 33 is disposed above the motor case 20. The sensor cover 33 is a resin molded product, and has an upper wall 34 covering the sensor magnet portion 26 from above and a peripheral wall 35 surrounding the side from the side. The outer peripheral edge of the sensor cover 33 is formed radially inward of the outer peripheral edge of the motor case 20 in plan view. That is, the diameter of the sensor cover 33 is smaller than the diameter of the motor case 20. The sensor cover 33 is attached to the motor case 20 by an attachment structure described later.

  The mounting substrate 32 on which the sensor 31 is mounted is fixed to the inside of the sensor cover 33. The sensor 31 is disposed apart from the sensor magnet unit 26 by a predetermined distance. The sensor 31 is axially opposed to the sensor magnet unit 26. The sensor 31 detects a magnet (not shown) disposed in the sensor magnet unit 26 which rotates with the rotation of the shaft 24, and detects the rotational position of the rotor 23. The mounting substrate 32 is fixed to the sensor cover 33 by a substrate mounting structure described later.

  Further, a wiring hole (not shown) is formed in the peripheral wall 35 of the sensor cover 33, and the communication wiring 62 (see FIG. 1) drawn in via the wiring hole is connected to the mounting substrate 32.

  In the motor 10, a driving current input from an external device through the current wiring 61 is supplied to the stator 22, whereby the stator 22 is excited. At this time, the rotor 23 and the shaft 24 rotate around the central axis C by the magnetic field generated from the stator 22.

  The motor case 20 is made of metal, and the sensor cover 33 is made of resin. That is, the motor case 20 is made of a material having a smaller linear expansion coefficient than the sensor cover 33. For this reason, the motor case 20 is less deformed even when the temperature of the motor 10 is increased.

(2. Sensor mounting structure)
FIG. 3 shows an exploded perspective view of the motor 10, and FIG. 4 shows a perspective view of the sensor cover 33 as viewed from below. An open lower surface of the sensor cover 33 is covered by the upper surface 20 a of the motor case 20.

  Further, the peripheral wall 35 has two opposing flat surfaces 35 a and two opposing curved surfaces 35 b. The flat portions 35a and the curved portions 35b are alternately arranged in the circumferential direction. The curved surface portion 35 b is a curved surface convex outward in the radial direction.

  The flat portion 35a is formed with a pair of slits 38 extending in the axial direction. Between the slits 38, a columnar piece 38a whose upper end is supported by a cantilever is formed. An arm portion 37a extends radially outward at the lower end of the columnar piece 38a. That is, the arm portion 37a is disposed on the side surface of the flat portion 35a. At the tip of the arm 37a, a projection 37b is provided which protrudes axially downward. The protrusion 37 b is fitted in a fitting hole 29 provided on the top surface 20 a of the motor case 20.

  An engaging claw 36 is provided on the curved surface portion 35 b. The engagement claw 36 has a standing portion 36 a and a bending portion 36 b. The standing portion 36a extends axially downward from the lower end of the curved surface portion 35b. That is, the engagement claws 36 are disposed on the lower surface of the curved surface portion 35b. The bending portion 36b is bent inward in the radial direction from the tip of the standing portion 36a.

  In addition, since the columnar piece 38a is disposed in the flat surface portion 35a, the columnar piece 38a is more easily bent in the radial direction than provided in the curved surface portion 35b.

  A root portion 37c is provided at the root of the protrusion 37b. The root portion 37 c has a diameter larger than that of the fitting hole 29, and the outer peripheral edge of the root portion 37 c is positioned more outward than the rim of the fitting hole 29. Accordingly, when the engagement claw 36 engages with the engagement hole 28, the root portion 37c presses the periphery of the fitting hole 29 downward in the axial direction.

  Inside the sensor cover 33, a shielding portion 39 which protrudes from the inner surface of the peripheral wall 35 and covers the slit 38 is provided. Thereby, dust which intrudes into the inside of the sensor cover 33 through the slit 38 can be shielded by the shielding portion 39.

  The upper wall 34 of the sensor cover 33 is provided with a pair of grip holes 34 a. The grip hole 34a is disposed to face the bending portion 36b in the axial direction. As a result, the jig can be inserted into the grip hole 34 a and the sensor cover 33 can be easily gripped. Therefore, the assembling workability of the motor case 20 and the sensor cover 33 is improved.

  An annular rib 34 b protrudes axially downward on the inner surface of the upper wall 34. The ribs 34 b prevent the upper wall 34 from being deformed. As a result, it is possible to prevent the detection error of the sensor 31 from being generated due to the position of the mounting substrate 32 fixed to the upper wall 34 being shifted. Further, the annular rib 34b is disposed radially inward of the flat surface portion 35a and the curved surface portion 35b. Therefore, even if the stress acting from the flat portion 35a and the stress acting from the curved portion 35b are different, the stress acting on the center of the sensor cover 33 can be made more uniform by providing the annular rib 34b.

  FIG. 5 is a top view of the motor case 20, and FIG. 6 is a top view showing the engagement hole 28 in an enlarged manner. In FIGS. 5 and 6, the engagement claws 36 shown by broken lines are inserted into the engagement holes 28.

  In the upper surface portion 20a of the motor case 20, an engagement hole 28 and a fitting hole 29 are provided at two points on either side of the central axis C, respectively. The engagement holes 28 and the fitting holes 29 are alternately arranged in the circumferential direction. The engagement hole 28 has a first hole 28a and a second hole 28b. The second hole 28 b is continuous with the first hole 28 a in the circumferential direction.

  The area of the first hole 28a is larger than the area of the second hole 28b. The radial width W1 of the first hole portion 28a is larger than the radial width W4 of the bent portion 36b. The radial width W2 of the second hole 28b is larger than the radial width W3 of the standing portion 36a. The radial width W2 of the second hole 28b is smaller than the radial width W4 of the bent portion 36b. The circumferential width W5 of the first hole portion 28a is larger than the circumferential width W6 of the bent portion 36b. That is, the engagement hole 28 is larger than the engagement claw 36 in the axial direction. The first engagement holes 28 a are larger than the engagement claws 36 in the axial direction. The second engagement hole 28 b is smaller than the engagement claw 36 in the axial direction. The engagement hole 28 is longer in the circumferential direction than the circumferential length of the bent portion 36 b.

  In the present embodiment, the sensor cover 33 is rotated in the circumferential direction (clockwise direction in FIG. 5) after the engagement claw 36 is inserted into the first hole 28a. Thereby, the engagement claw 36 moves in the circumferential direction, and the periphery of the second hole 28 b engages with the bending portion 36 b. At this time, the standing portion 36a is located inside the second hole 28b. That is, the engagement claw 36 is movable in the circumferential direction in the engagement hole 28 and engages with the periphery of the engagement hole 28. Note that "movable" means that the engaging claw 36 is movable when engaging with the periphery of the engaging hole 28 at the time of assembly. That is, as described later, in the state before the protrusion 37 b is fitted in the fitting hole 29 and the movement of the sensor cover 33 in the circumferential direction and the radial direction is limited, the movement is “movable”.

  Thus, the sensor cover 33 can be easily attached to the motor case 20. Therefore, the number of parts of the motor 10 can be reduced to reduce the manufacturing cost and to improve the assembling workability. In addition, it is possible to reduce the axial displacement of the sensor cover 33 with respect to the motor case 20 due to the vibration at the time of driving the motor 10, and to prevent the detection error of the sensor 31.

  Further, by providing the plurality of engagement claws 36 and the plurality of engagement holes 28, the axial displacement of the sensor cover 33 with respect to the motor case 20 can be further reduced.

  Further, when the engagement claw 36 is inserted into the first hole 28a, the arm 37a is elastically deformed so that the projection 37b is in contact with the upper surface 20a. When the sensor cover 33 is rotated in the circumferential direction and the engagement claw 36 is disposed in the second hole 28 b, the protrusion 37 b is fitted in the fitting hole 29. Thereby, the movement of the sensor cover 33 in the circumferential direction and the radial direction is limited. Therefore, it is possible to prevent the engagement claw 36 engaged with the periphery of the second hole portion 28b from moving to the opposite side to that at the time of engagement and disengagement.

  It is more preferable to reduce the positional deviation of the sensor cover 33 by reducing the fitting gap between the projection 37 b and the fitting hole 29. At this time, even if the protrusion 37b and the fitting hole 29 are shifted in the radial direction due to processing accuracy, the protrusion 37b can be easily fitted in the fitting hole 29 by elastic deformation of the columnar piece 38a.

  FIG. 7 is a cross-sectional view showing a part of the sensor cover 33 and the motor case 20 in an enlarged manner. The lower end of the root portion 37 c is located below the lower end of the peripheral wall 35. As a result, when the engagement claw 36 engages with the engagement hole 28, the tip of the arm 37a is lifted upward by the root 37c.

  At this time, the arm portion 37 a is bent and a force R 1 acting on the sensor cover 33 away from the upper surface portion 20 a acts. That is, the arm portion 37a is elastically deformed by the fitting of the projection 37b and the fitting hole 29, and biases the sensor cover 33 in the direction away from the motor case 20 in the axial direction. As a result, the bending portion 36 b is pressed around the second hole 28 b, and axial displacement of the sensor cover 33 with respect to the motor case 20 can be further reduced.

  Further, a plurality of engaging claws 36 are provided, and the protrusion 37 b is disposed between the plurality of engaging claws 36 in the circumferential direction. Thus, when the force R1 for moving the sensor cover 33 away from the motor case 20 acts via the arm portion 37a in which the projection 37b is disposed, the plurality of adjacent bent portions 36b can be stably stabilized in the second hole portion 28b. It can be pressed around. Thereby, it is possible to further reduce the axial displacement of the sensor cover 33 with respect to the motor case 20.

  Further, since the lower end of the projection 37b is positioned above the lower end of the engagement claw 36, the arm 37a is inserted when the engagement claw 36 is inserted into the first hole 28a and the projection 37b contacts the upper surface 20a. The amount of elastic deformation can be reduced. Thereby, breakage of the arm 37a can be prevented.

  Further, by arranging the root portion 37c at the root of the projection 37b, when the projection 37b is fitted in the fitting hole 29, the tip of the arm 37a can be lifted upward. In FIG. 7, the inclined surface of the root portion 37c is formed in a straight line in a cross section perpendicular to the radial direction. However, the sloped surface of the root portion 37c may be formed in an outwardly convex curved shape in a cross section perpendicular to the radial direction. That is, the sloped surface of the root portion 37c may have an R shape connecting the protrusion 37b and the arm 37a.

  Note that, instead of the root portion 37c, a protruding portion that protrudes axially downward from the lower surface of the arm portion 37a may be provided at a position different from the protruding portion 37b. At this time, the protrusion amount of the protrusion 37 b is larger than the protrusion amount of the protrusion. As a result, in a state where the protrusion 37b is fitted in the fitting hole 29, the lower end of the protrusion can contact the upper surface 20a and lift the tip of the arm 37a upward. Further, the upper surface portion 20a may be provided with a convex portion that protrudes axially upward and contacts the arm portion 37a.

(3. Board mounting structure)
8 shows a bottom view of the mounting substrate 32, and FIG. 9 shows a cross-sectional view along the line A-A in FIG. The mounting substrate 32 has a sensor 31 disposed on the central axis C, and has a first through hole 32 a and a second through hole 32 b around the sensor 31. The positioning portion 52 is inserted into the first through hole 32a, and the fixing portion 53 is inserted into the second through hole 32b.

  The positioning portion 52 and the fixing portion 53 are integrally formed with the sensor cover 33, and project axially downward from the inner surface of the upper wall 34 of the sensor cover 33.

  Three fixing portions 53 are provided, and two positioning portions 52 are provided. Further, the positioning portion 52 is disposed between the fixing portions 53 adjacent in the circumferential direction. Further, the positioning portion 52 is disposed at a position where the distance in the radial direction from the central axis C is shorter than that of the fixing portion 53. Thus, the mounting substrate 32 can be stably held by the positioning unit 52 and the fixing unit 53.

  The positioning section 52 has a circular horizontal cross section, and is tapered such that the outer diameter decreases in the axial direction downward. This prevents the mounting substrate 32 from being shifted in the direction perpendicular to the axial direction by being inserted into the first through holes 32a. Note that providing the positioning portions 52 at two or more places prevents the mounting substrate 32 from rotating and shifting in the circumferential direction centering on the positioning portions 52.

  The fixing portion 53 protrudes axially downward from the support portion 54, and has a caulking portion 53a and an insertion portion 53b.

  The support portion 54 protrudes axially downward from the inner surface of the upper wall 34, and has an outer diameter larger than that of the second through hole 32b. Therefore, when the fixing portion 53 is inserted into the second through hole 32 b, the support portion 54 and the mounting substrate 32 are in contact with each other, and a gap is formed between the mounting substrate 32 and the upper wall 34. Thereby, even when the sensor cover 33 is deformed, it is possible to prevent the detection error of the sensor 31 from being generated due to the position of the mounting substrate 32 fixed to the upper wall 34 being shifted.

  The insertion portion 53 b has a cylindrical shape, and the inner diameter of the insertion portion 53 b is smaller than the outer diameter of the support portion 54. The insertion portion 53 b axially protrudes from the support portion 54 and is inserted into the second through hole 32 b. The caulking portion 53 a is formed by caulking the distal end portion of the insertion portion 53 b and fixes the mounting substrate 32 to the upper wall 34.

  The fixing portion 53 and the support portion 54 may be arranged at different positions. In this case, the insertion portion 53 b axially protrudes from the inner surface of the upper wall 34.

  FIG. 10 is a cross-sectional view showing a state before the mounting substrate 32 is fixed to the sensor cover 33. As shown in FIG. FIG. 10 shows a state in which the inner surface of the upper wall 34 is directed upward. The tip of the insertion portion 53 b inserted into the second through hole 32 b of the mounting substrate 32 protrudes from the mounting substrate 32. By heat welding and caulking the tip of the insertion portion 53 b, a caulking portion 53 a is formed, and the mounting substrate 32 is fixed to the sensor cover 33.

  At this time, the positioning portion 52 prevents the mounting substrate 32 from being crimped in a state of being shifted in a direction perpendicular to the axial direction. Therefore, the positioning accuracy of the mounting substrate 32 can be improved to prevent the positional deviation of the sensor 31 and the occurrence of the detection error of the sensor 31 can be prevented.

  The mounting substrate 32 is fixed by the caulking portion 53 a in a state where the tapered positioning portion 52 is inserted into the first through hole 32 a and the mounting substrate 32 is pressed in the insertion direction. Therefore, a reaction force acts on the periphery of the first through hole 32a in such a manner as to come out of the positioning portion 52 in the direction opposite to the insertion direction. As a result, the workability at the time of heat welding and caulking the distal end portion of the insertion portion 53b is improved.

  In addition, a force to press the mounting substrate 32 in the insertion direction from the caulking portion 53 a and a force in the direction opposite to the insertion direction from the positioning portion 52 work. As a result, the mounting substrate 32 can be further prevented from being displaced in the axial direction with respect to the sensor cover 33 due to the vibration when the motor 10 is driven.

Second Embodiment
Next, a second embodiment of the present invention will be described. FIG. 11 is a top view of the motor case 20 of the motor 10 according to the second embodiment, and FIG. 12 is a perspective view of the sensor cover 33. For convenience of explanation, the same parts as those of the first embodiment shown in FIGS. 1 to 10 described above are designated by the same reference numerals. In the second embodiment, the shapes of the engagement claws 36 and the engagement holes 28 are different from those in the first embodiment. The other parts are the same as in the first embodiment. In FIG. 11, the engagement claws 36 are shown by broken lines, and show a state of being inserted into the engagement holes 28.

  The engagement hole 28 is formed in a circumferentially extending arch shape. The standing portion 36a of the engaging claw 36 extends in the axial direction, and the bending portion 36b is bent in the circumferential direction from the tip of the standing portion 36a. At this time, the radial width of the engagement hole 28 is larger than the radial width of the bent portion 36 b. The circumferential width of the engagement hole 28 is larger than the circumferential width of the bent portion 36 b. That is, the engagement hole 28 is larger than the engagement claw 36 in the axial direction. The engagement hole 28 is longer in the circumferential direction than the circumferential length of the bent portion 36 b.

  The engagement claw 36 engages with the periphery of the engagement hole 28 by inserting the engagement claw 36 into the engagement hole 28 and rotating the sensor cover 33 in the circumferential direction. That is, the engagement claw 36 is movable in the circumferential direction in the engagement hole 28 and engages with the periphery of the engagement hole 28. At this time, the projection 37 b (see FIG. 7) is fitted in the fitting hole 29 to restrict movement of the sensor cover 33 in the circumferential direction. According to the present embodiment, the second hole portion 28 b is not provided, and the engagement claw 36 can be engaged only with the first hole portion 28 a. Therefore, the punching of the engagement hole 28 can be simplified. In addition, the same effect as that of the first embodiment can be obtained.

Third Embodiment
Next, a third embodiment of the present invention will be described. FIG. 13 is a top view of the motor case 20 of the motor 10 according to the third embodiment. For convenience of explanation, the same parts as those of the first embodiment shown in FIGS. 1 to 10 described above are designated by the same reference numerals. In the third embodiment, the shapes of the engagement claws 36 and the engagement holes 28 are different from those in the first embodiment. The other parts are the same as in the first embodiment. Note that the engagement claws 36 indicated by broken lines in FIG. 13 are inserted into the engagement holes 28.

  The engagement hole 28 has a first hole 28 a extending in the circumferential direction, and a second hole 28 b radially continuous from one end of the first hole 28 a. The second hole 28b of one engagement hole 28 extends inward from the first hole 28a, and the second hole 28b of the other engagement hole 28 extends outward from the first hole 28a.

  Similarly to the second embodiment shown in FIG. 12 described above, the bending portion 36b is bent in the circumferential direction from the tip end of the standing portion 36a extending in the axial direction. The erected portion 36a and the bent portion 36b are formed so as to be insertable into the first hole 28a, and the erected portion 36a is formed so as to be inserted into the second hole 28b. That is, the area of the first hole 28a is larger than the area of the second hole 28b. The radial width of the first hole 28a is larger than the radial width of the bent portion 36b. The circumferential width of the first hole portion 28a is larger than the circumferential width of the bent portion 36b. The circumferential width of the second hole 28b is larger than the circumferential width of the standing portion 36a. The circumferential width of the second hole 28b is smaller than the circumferential width of the bent portion 36b. That is, the engagement hole 28 is larger than the engagement claw 36 in the axial direction. The first engagement holes 28 a are larger than the engagement claws 36 in the axial direction. The second engagement hole 28 b is smaller than the engagement claw 36 in the axial direction. The engagement hole 28 is longer in the radial direction than the radial length of the bent portion 36 b.

  After inserting the erected portion 36a and the bent portion 36b into the first hole portion 28a, the engagement claw 36 is moved in the radial direction by moving the sensor cover 33 in the radial direction (direction orthogonal to the central axis C). And engages with the periphery of the second hole 28b. That is, the engagement claw 36 is movable in the direction perpendicular to the axial direction in the engagement hole 28 and engages with the periphery of the engagement hole 28. At this time, the projection 37 b (see FIG. 7) is fitted in the fitting hole 29 to restrict movement of the sensor cover 33 in the circumferential direction. According to this embodiment, the same effect as that of the first embodiment can be obtained.

Fourth Embodiment
Next, a fourth embodiment of the present invention will be described. FIG. 14 is a top view of the motor case 20 of the motor 10 according to the fourth embodiment. For convenience of explanation, the same parts as those of the first embodiment shown in FIGS. 1 to 10 described above are designated by the same reference numerals. In the fourth embodiment, the shapes of the engagement claws 36 and the engagement holes 28 are different from those in the first embodiment. The other parts are the same as in the first embodiment. The engagement claws 36 shown by broken lines in FIG. 14 are inserted into the engagement holes 28.

  The engagement hole 28 is formed in a circumferentially extending arch shape. The standing portion 36a of the engaging claw 36 extends in the axial direction, and the bending portion 36b is bent in the radial direction from the tip of the standing portion 36a. The bent portion 36b of one engaging claw 36 protrudes radially inward from the standing portion 36a, and the bent portion 36b of the other engaging claw 36 protrudes radially outward from the standing portion 36a. The engagement hole 28 is formed so that the standing portion 36 a and the bending portion 36 b can be inserted. That is, the radial width of the engagement hole 28 is larger than the radial width of the bent portion 36 b. The circumferential width of the engagement hole 28 is larger than the circumferential width of the bent portion 36 b. That is, the engagement hole 28 is larger than the engagement claw 36 in the axial direction.

  After inserting the erected portion 36 a and the bent portion 36 b into the engagement hole 28, the engagement claw 36 moves in the radial direction by moving the sensor cover 33 in the radial direction, and engages with the periphery of the engagement hole 28. Do. That is, the engagement claw 36 is movable in the direction perpendicular to the axial direction in the engagement hole 28 and engages with the periphery of the engagement hole 28. At this time, the projection 37 b (see FIG. 7) is fitted in the fitting hole 29 to restrict movement of the sensor cover 33 in the circumferential direction. According to this embodiment, the same effect as that of the first embodiment can be obtained.

Fifth Embodiment
Next, a fifth embodiment of the present invention will be described. FIG. 15 is a cross-sectional view showing the mounting structure of the sensor cover 33 and the mounting substrate 32 of the motor 10 of the fifth embodiment. FIG. 10 shows a state in which the inner surface of the upper wall 34 is directed upward. Further, for convenience of explanation, the same parts as those of the first embodiment shown in the above-mentioned FIG. 1 to FIG. In the fifth embodiment, the structure of the fixing portion 53 is different from that of the first embodiment. The other parts are the same as in the first embodiment.

  The fixing portion 53 is formed of a screw 55, and the mounting portion 32 is fixed by screwing the screw 55 in a screw hole 56 provided in the support portion 54. According to this embodiment, the same effect as that of the first embodiment can be obtained.

  The fixing portion 53 and the support portion 54 may be arranged at different positions, and the screw hole 56 may be provided in the upper wall 34.

(4. Other)
The above embodiments are merely illustrative of the present invention. The configuration of the embodiment may be changed as appropriate without departing from the technical concept of the present invention. Also, the embodiments may be implemented in combination as far as possible.

  In the above embodiment, the engagement claw 36 is provided on the sensor cover 33 and the engagement hole 28 is provided on the motor case 20. However, the motor case 20 is provided with the engagement claw 36 and the sensor cover 33 is provided with the engagement hole 28 It is also good. In this case, the engagement claws 36 project axially upward from the upper surface portion 20 a of the motor case 20, and the engagement holes 28 are disposed on the lower end surface of the peripheral wall 35.

  In the above embodiment, the protrusion 37b is provided on the sensor cover 33 and the fitting hole 29 is provided on the motor case 20. However, the protrusion 37b is provided on the motor case 20 and the fitting hole 29 is provided on the sensor cover 33 It is also good. In this case, the projection 37b protrudes upward in the axial direction from the upper surface 20a of the motor case 20, and the fitting hole 29 is disposed at the tip of the arm 37a.

  Further, in the above embodiment, the engagement claw 36 is movable in the direction perpendicular to the axial direction in the engagement hole 28 and engaged with the periphery of the engagement hole 28, but restricts the axial movement. Other structures may be used as long as they are structures. For example, the engagement claw and the engagement hole may be engaged by snap fitting.

  Moreover, although the said embodiment demonstrated the inner-rotor type motor, this invention is applicable also to an outer-rotor type motor.

  In the above embodiment, the mounting structure of the sensor 31 for detecting the rotational position of the rotor 23 has been described, but the present invention may be applied to a sensor mounting structure for detecting a predetermined characteristic of the main body covered by the case. it can.

  The motor of the present invention is suitable, for example, for a motor for electric power steering. In addition, the sensor attachment structure of this invention can be utilized also for another electronic device.

DESCRIPTION OF SYMBOLS 10 ... Motor 20 20 motor case 20a upper surface part 20b body part 20c upper side holding part 21 upper surface through-hole 22 stator 22a ... Stator core, 22b ... coil, 23 ... rotor, 24 ... shaft, 25a ... upper bearing, 25b ... lower bearing, 26 ... sensor magnet, 28 ... Engaging hole, 28a: first hole, 28b: second hole, 29: fitting hole, 31: sensor, 32: mounting board, 32a: through hole ( First through hole), 32b through hole (second through hole) 33 sensor cover 34 upper wall 34a gripping hole 34b rib 35 Peripheral wall, 35a: flat portion, 35b: curved portion, 36: engaging claw, 36a: Installation portion, 36b: bending portion, 37a: arm portion, 37b: projection portion, 37c: root portion, 38: slit, 38a: columnar piece, 39: shielding portion 40: flange portion 40a lower holding portion 52 positioning portion 53 fixing portion 53a caulking portion 53b insertion portion 54 support Part, 55: screw, 56: screw hole, 61: current wiring, 62: communication wiring, C: central axis, R1: force

Claims (10)

A rotor having an axially extending shaft;
A stator radially opposed to the rotor;
A motor case for housing the rotor and the stator;
A sensor that detects the rotational position of the rotor;
A sensor cover that accommodates the sensor and is attached to one end of the motor case in the axial direction;
Equipped with
One of the motor case and the sensor cover has an engagement hole, and the other has an engagement claw that engages with the periphery of the engagement hole,
The sensor cover is
An arm portion extending radially outward from the peripheral wall;
One of the distal end of the arm portion and the motor case has a protrusion that protrudes in the axial direction, and the other has a fitting hole into which the protrusion fits.
The arm portion is elastically deformed by the fitting of the projection portion and the fitting hole, and biases the sensor cover in the axial direction and in a direction away from the motor case. The protrusion has a root at its root,
The motor according to claim 1, wherein an outer peripheral edge of the root portion is positioned more outward than a peripheral edge of the fitting hole. The sensor cover is
A pair of axially extending slits on the peripheral wall;
A columnar piece disposed between the slits and supported at its upper end by a cantilever;
Have
The motor according to claim 1, wherein the arm portion extends from an outer surface of the columnar piece. The sensor cover is
The motor according to claim 3, further comprising a shielding portion that protrudes from the inner surface of the peripheral wall and covers the slit. The peripheral wall of the sensor cover has a flat portion,
The motor according to any one of claims 1 to 4, wherein the arm portion is positioned on a side surface of the flat portion. The engagement claw and the projection are disposed on the sensor cover;
The motor according to any one of claims 1 to 5, wherein a lower end of the protrusion is positioned above a lower end of the engagement claw. Having a plurality of the engaging claws,
The motor according to any one of claims 1 to 6, wherein the protrusion is disposed between the plurality of engagement claws in a circumferential direction.   The motor according to any one of claims 1 to 7, wherein the motor case is made of a material having a smaller linear expansion coefficient than the sensor cover.   The motor according to any one of claims 1 to 8, wherein the sensor cover has an annular rib protruding from an inner surface and surrounding the sensor. In a sensor mounting structure in which a sensor for detecting a predetermined characteristic of a main body is attached to the main body,
A case covering the main body;
A sensor cover which houses the sensor and is mounted on the installation surface of the case;
One of the case and the sensor cover has an engagement hole, and the other has an engagement claw inserted into the engagement hole,
The sensor cover is
An arm portion extending radially outward from the peripheral wall;
One of the distal end of the arm portion and the case has a protrusion that protrudes in the axial direction, and the other has a fitting hole into which the protrusion fits.
The sensor mounting structure according to claim 1, wherein the arm portion is elastically deformed by the fitting of the protrusion and the fitting hole to bias the sensor cover away from the installation surface.

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