JP2014128096A - Motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To fix a rotation detection sensor at a predetermined position through high-accuracy positioning in a motor.SOLUTION: A rotation detection sensor 22 constituting a motor 10 is disposed in such a manner that a plurality of holder holes 62 oppose a boss 36 of a cover member 28, and the rotation detection sensor 22 is positioned with respect to the cover member 28 by fitting a fitting part 48 of a holder 44 inserted through the holder holes 62 to a fitting hole 42 of the boss 36. By threading a mounting bolt 40 inserted into a through hole 38 of the boss 36 into a screw hole 46 of the holder 44, the rotation detection sensor 22 is held between a flange part 52 of the holder 44 and the cover member 28. In such a case, even if a case 60 of the rotation detection sensor 22 is made of a resin material, an axial force of the mounting bolt 40 is applied to the cover member 28 and the holder 44 made of a metallic material, such that cracking or the like may also be prevented.

Description

  The present invention relates to an electric motor including a rotation detection sensor capable of detecting the rotation speed of a rotor.

  2. Description of the Related Art Conventionally, an electric motor that is excited by energizing a coil and rotates a shaft together with a rotor provided with a permanent magnet is known. As such an electric motor, for example, a brushless motor as disclosed in Patent Document 1 is used, and a rotation detection sensor capable of detecting the number of rotations and the rotation angle of the rotor is provided for the purpose of performing rotation control. The rotation detection sensor is arranged on the inner surface of the motor case so as to face the conductor pattern mounted on the side surface of the rotor. Then, an overcurrent is generated by energizing the conductor pattern, and a rotation speed or a rotation angle is calculated by detecting a change in inductance caused thereby, and rotation control of the electric motor is performed based on the rotation speed.

JP 2009-77500 A

  In the electric motor as described above, since the rotation detection sensor is accurately arranged at a predetermined position for the first time, the rotation number of the rotor is insufficiently positioned. In the case where a positional deviation or inclination occurs, there arises a problem that the detection accuracy is lowered.

  The present invention has been made in consideration of the above-described problems, and an object thereof is to provide an electric motor capable of positioning and fixing a rotation detection sensor at a predetermined position with high accuracy.

In order to achieve the above object, the present invention provides a rotor, an annular stator that is provided on the outer peripheral side of the rotor and is wound with a coil, and is formed of a metal material and accommodates the rotor and the stator. An electric motor having a housing and rotating the rotor under an energization action to the coil;
A rotation detection sensor provided on the housing, having a case made of a resin material, and detecting a rotation speed or a rotation angle of the rotor;
An attachment member formed of a metal material, engaged or fixed to the case, and fixing the rotation detection sensor to the housing;
With
The mounting member has a protrusion protruding toward the housing, the housing has a recess into which the protrusion is inserted, and at least one of the protrusion and the recess. A screw portion to which the mounting bolt is screwed is formed, and the housing and the mounting member are coupled by screwing the mounting bolt into the screw portion in a state where the convex portion is inserted into the concave portion. It is characterized by that.

  According to the present invention, the housing constituting the electric motor is provided with a rotation detection sensor having a case made of a resin material that detects the rotation speed or rotation angle of the rotor, and the rotation detection sensor is provided in the case. The convex portion of the mounting member to be engaged or fixed is inserted into the concave portion formed in the housing, and the mounting bolt is screwed into the screw portion formed in at least one of the convex portion and the concave portion. The housing and the mounting member are connected with the rotation detection sensor in between.

  Therefore, the rotation detection sensor is made to be highly accurate with respect to the housing by engaging the convex portion and the concave portion of the housing and the mounting member which are made of a metal material and formed with higher accuracy than the resin material. In addition, the rotation detection sensor can be easily fixed to the housing by screwing the mounting bolt into the thread portion of the convex portion or the concave portion.

  As a result, the rotation detection sensor can be positioned and fixed at a predetermined position in the housing with high accuracy without any positional deviation or inclination, and accordingly, the rotation detection sensor increases the rotation speed and rotation angle of the rotor. It can be detected with accuracy.

  Further, by forming a communication path that communicates the inside and the outside of the housing in the vicinity of the threaded portion, the outside and the inside of the housing can be communicated through the communication path. For example, a breathing hole must be provided separately. It can be made to function as a breathing hole with a simple structure.

  Furthermore, the rotation detection sensor may be formed in a fan shape in cross section.

  Furthermore, the electric motor may be a brushless motor.

  According to the present invention, the following effects can be obtained.

  That is, the housing constituting the electric motor is provided with a rotation detection sensor having a case made of a resin material that detects the rotation speed or rotation angle of the rotor, and the rotation detection sensor is engaged with or fixed to the case. By engaging the convex portion of the mounting member with the concave portion formed in the housing, the rotation detection sensor is positioned with high accuracy relative to the housing, and the mounting bolt is screwed into the screw portion. The rotation detection sensor can be fixed with respect to the housing in a positioned state.

1 is an overall cross-sectional view of an electric motor according to an embodiment of the present invention. It is an expanded sectional view which shows the attachment bolt vicinity which fixes the rotation detection sensor in the electric motor of FIG. It is a front view of the cover member shown in FIG.

  DESCRIPTION OF EMBODIMENTS Preferred embodiments of an electric motor according to the present invention will be given and described in detail below with reference to the accompanying drawings. In FIG. 1, reference numeral 10 indicates an electric motor according to an embodiment of the present invention.

  The electric motor 10 is, for example, a brushless motor, and as shown in FIG. 1, a housing 14 having a space 12 therein, a shaft 16 rotatably provided in the housing 14, A rotor 18 provided on the outer peripheral side, a stator 20 disposed on the outer peripheral side of the rotor 18 and fixed to the housing 14, and a rotation detection sensor 22 that detects the rotation speed and rotation angle of the rotor 18 are included.

  The housing 14 is formed at one end thereof with a first support portion 26 that supports the shaft 16 via a first bearing 24, and the first support portion 26 is provided on an axis that is the center of the housing 14. The first bearing 24 is mounted on the inner peripheral surface of the first support portion 26 formed in a cylindrical shape. For example, the shaft 16 is disposed on the axis of the housing 14 via the first bearing 24 formed of a ball bearing. It is supported rotatably.

  Further, the other end portion of the housing 14 is formed and opened with a substantially constant diameter that is larger than the first support portion 26, and is closed when the cover member 28 is attached.

  The cover member 28 is made of, for example, a metal material. As shown in FIGS. 1 and 2, the cover member 28 has a disk-shaped main body 30 and a peripheral wall 32 formed at the outer edge of the main body 30. And a second support part 34 formed at the center of the main body part 30. The main body 30 is formed in a substantially planar shape, and a plurality of (for example, three) bosses 36 are formed so as to protrude in the axial direction (arrow A direction) from the outer wall surface 28a. The bosses 36 are provided on the same circumference spaced from the center of the main body 30 by a predetermined radius, and protrude in a cylindrical shape with a predetermined height with respect to the main body 30. A through hole 38 is formed in the center of the boss 36 along the axial direction (directions of arrows A and B), and a mounting bolt 40 for fixing the rotation detection sensor 22 is inserted therethrough.

  In addition, a fitting hole (concave portion) 42 opened to the inner wall surface 28 b side of the cover member 28 is formed inside the boss 36, and the fitting hole 42 is coaxial with the through hole 38 and is formed in the through hole 38. The diameter is increased. A part of a holder (attachment member) 44 for positioning and fixing the rotation detection sensor 22 is inserted into the fitting hole 42.

  The holder 44 is formed of, for example, a metal material, is attached to each boss 36, and has a cylindrical shape having a screw hole (threaded portion) 46 penetrating along the axial direction (arrows A and B directions) at the center. It is formed. The holder 44 includes a fitting portion (convex portion) 48 formed at one end portion, an insertion portion 50 adjacent to the fitting portion 48 and having a diameter expanded with respect to the fitting portion 48, and the other end portion. And a flange portion 52 that is formed and engaged with the stepped portion 64 of the rotation detection sensor 22. The screw hole 46 is formed in a straight line so as to pass through the fitting portion 48, the insertion portion 50, and the flange portion 52, and the rotation detection sensor 22 is disposed between the cover member 28 and the holder 44. The mounting bolt 40 inserted through the boss 36 of the cover member 28 is screwed into the screw hole 46.

  Further, the length of the fitting portion 48 along the axial direction (directions of arrows A and B) is formed shorter than the depth of the fitting hole 42 of the boss 36. Therefore, when the end surface of the insertion portion 50 of the holder 44 contacts the inner wall surface 28 b of the cover member 28, the end portion of the fitting portion 48 does not contact the bottom surface of the fitting hole 42.

  Further, a first groove portion 54 extending along the axial direction (the directions of arrows A and B) is formed on the outer peripheral surface of the fitting portion 48, and the first groove portion 54 is formed on the end surface of the insertion portion 50. It is connected to and communicates with a second groove 56 extending in the radially outward direction. The second groove 56 is connected to and communicates with a communication groove 58 formed on one side surface of the rotation detection sensor 22. Thereby, the space 12 covered with the housing 14 and the cover member 28 and the outside of the electric motor 10 communicate with each other through the first and second groove portions 54 and 56 and the communication groove 58 to function as a breathing hole.

  As shown in FIGS. 1 to 3, the rotation detection sensor 22 includes, for example, a case 60 made of a resin material and having a fan-shaped case 60 having a semicircular recess 22a at the center thereof. Inside the 60, a plurality of pattern coils (not shown) are provided at equal intervals. The rotation detection sensor 22 is formed with a plurality of holder holes 62 on the same circumference spaced from the center by a predetermined radius, and the holder holes 62 are spaced apart from each other at equal intervals along the circumferential direction of the rotation detection sensor 22. The insertion portions 50 of the holders 44 are respectively inserted therein. The inner peripheral diameter of the holder hole 62 is formed to be approximately equal to or slightly larger than the outer peripheral diameter of the insertion portion 50 in the holder 44.

  Further, a stepped portion 64 communicating with the holder hole 62 is formed in the rotation detection sensor 22 on the other end surface opposite to the one end surface that contacts the cover member 28. The stepped portion 64 has, for example, a circular cross section and is recessed at a predetermined depth with respect to the other end surface. Then, when the insertion portion 50 is inserted into the holder hole 62, the flange portion 52 of the holder 44 is inserted into the stepped portion 64. The numbers of the holder holes 62 and the stepped portions 64 are set corresponding to the number of the bosses 36 in the cover member 28.

  Since the depth of the stepped portion 64 is substantially equal to or slightly larger than the thickness of the flange portion 52, the flange portion 52 inserted into the stepped portion 64 protrudes from the other end surface of the rotation detection sensor 22. There is nothing to do.

  The rotation detection sensor 22 is disposed such that the recess 22a is on the center side (second support portion 34 side) of the cover member 28, and the positions of the boss 36 and the holder hole 62 of the cover member 28 are matched. Thus, the holder 44 is inserted into the holder hole 62 and the mounting bolt 40 is screwed into the screw hole 46, so that it is fixed in close contact with the inner wall surface 28 b of the cover member 28.

  The peripheral wall portion 32 is bent at a substantially right angle with respect to the main body portion 30 and is formed in an annular shape. Then, the housing 14 and the cover member 28 are coupled together by tightening the housing 14 and the cover member 28 with a bolt (not shown) in a state where the end portion of the peripheral wall portion 32 is in contact with the other end portion of the housing 14. As a result, the other end of the housing 14 that is opened is closed by the cover member 28.

  The second support portion 34 is formed coaxially with the first support portion 26 of the housing 14 and is formed in a cylindrical shape protruding toward the first support portion 26 side. And the 2nd bearing 66 which consists of a ball bearing, for example is mounted in the 2nd support part 34, and the other end part of the shaft 16 is rotatably supported.

  The shaft 16 has a predetermined length along the axial direction (directions of arrows A and B), and one end portion and the other end portion thereof are formed with a reduced diameter. The shaft 16 is disposed in the space 12 surrounded by the housing 14 and the cover member 28, and one end portion thereof is supported by the first bearing 24 and the other end portion thereof is supported by the second bearing 66 to rotate. Be free.

  An annular rotor 18 is press-fitted into a substantially central portion along the axial direction (arrow A, B direction) of the shaft 16, and a locking portion 68 formed on the outer peripheral surface on one end side (arrow B direction). Therefore, the movement toward the one end is restricted. The rotor 18 rotates integrally with the shaft 16.

  The rotor 18 is provided with a plurality of permanent magnets 70 in the vicinity of the outer peripheral surface thereof, and the permanent magnets 70 are arranged at equal intervals along the circumferential direction and are on the cover member 28 side (arrow A direction). The detection plate 72 is fixed to the other end. The detection plate 72 is formed, for example, by press-molding a plate material, and includes a base portion 74 that is in contact with the other end surface of the rotor 18, a connection portion 76 that is erected substantially perpendicular to the base portion 74, and the connection And a portion to be detected 78 that is bent substantially at right angles to the portion 76 and is expanded in the radially outward direction. The detected portion 78 is formed substantially parallel to the base portion 74.

  In the state where the base portion 74 is in contact with the rotor 18, the detection plate 72 contacts the disc-shaped holding plate 80 toward the cover member 28 (arrow A direction), and the locating pin 82 is inserted together with the holding plate 80. Then, the detection plate 72 is positioned relative to the rotor 18 in the rotational direction by being press-fitted into a positioning hole 84 formed on the other end surface of the rotor 18 and fixed.

  At this time, the detected portion 78 is disposed at a position facing the rotation detection sensor 22 mounted on the cover member 28, and when the detection plate 72 including the detected portion 78 rotates together with the rotor 18 and the shaft 16, The rotation number and rotation angle are detected by the rotation detection sensor 22.

  The stator 20 is formed in an annular shape and is fixed to the inner peripheral surface of the housing 14 at a position on the outer peripheral side of the rotor 18. An insulator 88 around which a coil 86 is wound is provided on one end surface and the other end surface of the stator 20, and the coil 86 is connected to a drive circuit 92 via a conducting wire 90. The conducting wire 90 and the drive circuit 92 are disposed on the lower side of the cover member 28 where the rotation detection sensor 22 is not provided.

  The rotor 18 provided with a plurality of permanent magnets 70 is rotated by a magnetic field generated by energizing the coil 86 from the drive circuit 92, and the rotational driving force is generated by the first and second bearings 24 and 66. It is output to the outside through one end of the shaft 16 that is rotatably supported.

  In the above-described embodiment, a case has been described in which the rotation detection sensor 22 that includes a plurality of pattern coils and can detect the number of rotations of the rotor 18 based on a change in inductance is used. However, the present invention is limited to this detection method. For example, a rotation detection sensor 22 using a Hall element capable of detecting the number of rotations of the rotor 18 by detecting a change in the magnetic field may be adopted, or the rotation of the rotor 18 may be adopted. The detection method is not particularly limited as long as it is a detection sensor that can detect the number and the like.

  Next, the case where the rotation detection sensor 22 is attached to the cover member 28 will be described.

  First, one end surface of the rotation detection sensor 22 is brought into contact with the inner wall surface 28b of the main body 30 in the cover member 28, and the plurality of bosses 36 and the holder holes 62 are arranged on the same axis. Then, the holder 44 is inserted into the holder hole 62 from the other end surface side of the rotation detection sensor 22. The holder 44 is inserted into the holder hole 62 from the fitting portion 48 side.

  The holder 44 has the insertion portion 50 inserted into the holder hole 62, the fitting portion 48 is inserted into the fitting hole 42 formed in the boss 36 of the cover member 28, and the flange portion 52 is stepped. When the end portion of the insertion portion 50 comes into contact with the inner wall surface 28b of the cover member 28, the movement toward the cover member 28 side (arrow A direction) is restricted.

  Finally, the mounting bolt 40 is inserted from the outside of the cover member 28 into the through hole 38 of the boss 36 and screwed into the screw hole 46 of the holder 44. Thus, the holder 44 is pulled toward the boss 36 (in the direction of arrow A) under the screwing action of the mounting bolt 40, and accordingly, the rotation detection sensor 22 is moved to the cover member 28 side by the flange portion 52 of the holder 44 ( It is pressed and clamped in the direction of arrow A).

  As a result, the rotation detection sensor 22 is positioned with respect to the cover member 28 by inserting the fitting portions 48 of the holder 44 inserted through the holder holes 62 into the fitting holes 42 of the cover member 28, respectively. The mounting bolt 40 inserted through the cover member 28 is fixed by being screwed into the screw hole 46 of the holder 44.

  At this time, since both the cover member 28 and the holder 44 are made of a metal material, even if the axial force generated when the mounting bolt 40 is fastened is applied, cracks and the like do not occur. The rotation detection sensor 22 can be securely fixed by the cover member 28 and the holder 44 that are formed.

  As described above, in the present embodiment, in the electric motor 10, the rotation detection sensor 22 having the resin material case 60 is applied to the inner wall surface 28 b of the cover member 28 that closes the other end of the housing 14. The rotation detection sensor 22 is inserted into the holder hole 62 of the case 60 and the fitting portion 48 of the holder 44 is engaged with the fitting hole 42 of the cover member 28. It is sandwiched between the holder 44 and the cover member 28 and can be positioned with high accuracy without causing any positional deviation or inclination with respect to a predetermined position.

  As a result, the rotation detection sensor 22 can be positioned with high accuracy through the holder 44 with respect to the cover member 28, and the rotation detection is performed by screwing the mounting bolt 40 into the screw hole 46 of the holder 44. Since the sensor 22 can be reliably fixed in a state in which the sensor 22 is positioned with respect to the cover member 28, in the electric motor 10, the rotation detection sensor 22 assembled at a predetermined position with high accuracy can control the rotation speed and rotation angle of the rotor 18. It can be detected with high accuracy.

  Further, by forming the cover member 28 and the holder 44 from a metal material, the positions of the screw holes 46, the outer peripheral diameters of the fitting portion 48 and the insertion portion 50, the inner peripheral diameters of the fitting hole 42, the holder hole 62, etc. Since it can be formed with high accuracy, the cover member 28 and the holder 44 are formed of a resin material by engaging the fitting portion 48 of the holder 44 with the fitting hole 42 of the cover member 28. In comparison, the rotation detection sensor 22 can be fixed with higher accuracy.

  Further, since the axial force at the time of fastening the mounting bolt 40 to fix the rotation detection sensor 22 is directly applied to the cover member 28 and the holder 44, the cover member 28 and the holder 44 are formed from a metal material. Thus, the rotation detection sensor 22 can be firmly fixed to the cover member 28 with a predetermined axial force without causing a crack or the like due to the axial force which is a concern when formed of a resin material. Can do.

  Furthermore, the housing 14 and the cover member 28 are formed by forming the first and second groove portions 54 and 56 in the holder 44 and forming the communication groove 58 communicating with the second groove portion 56 in the case 60 of the rotation detection sensor 22. The inside and the outside can be communicated with each other via the first and second groove portions 54 and 56 and the communication groove 58. As a result, it is not necessary to separately provide a breathing hole for communicating the inside and the outside of the housing 14, and it can function as a breathing hole with a simple structure. In addition, without providing the first and second groove portions 54 and 56 and the communication groove 58 as described above, for example, a gap is provided between the holder 44 and the cover member 28 and between the cover member 28 and the rotation detection sensor 22. It is good also as a structure which can communicate the exterior and the inside through the said gap | interval.

  In the above-described embodiment, the configuration in which the rotation detection sensor 22 and the holder 44 are formed separately and the holder 44 is inserted into the holder hole 62 has been described. However, the present invention is not limited to this. For example, the holder 44 made of a metal material may be integrally insert-molded with respect to the case 60 of the rotation detection sensor 22.

  Note that the electric motor according to the present invention is not limited to the above-described embodiment, and various configurations can be adopted without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 10 ... Electric motor 12 ... Space 14 ... Housing 16 ... Shaft 18 ... Rotor 20 ... Stator 22 ... Rotation detection sensor 28 ... Cover member 30 ... Main part 36 ... Boss 38 ... Through-hole 40 ... Mounting bolt 42 ... Fitting hole 44 ... Holder 46 ... Screw hole 48 ... Fitting part 50 ... Insertion part 52 ... Flange part 60 ... Case 62 ... Holder hole 64 ... Stepped part 72 ... Detection plate

Claims (4)

A rotor, an annular stator provided on the outer peripheral side of the rotor and wound with a coil, and a housing made of a metal material and housing the rotor and the stator, and under energization of the coil In the electric motor for rotating the rotor,
A rotation detection sensor that is provided in the housing and has a case made of a resin material and detects a rotation speed or a rotation angle of the rotor;
An attachment member formed of a metal material, engaged or fixed to the case, and fixing the rotation detection sensor to the housing;
With
The mounting member has a protrusion protruding toward the housing, the housing has a recess into which the protrusion is inserted, and at least one of the protrusion and the recess. A screw portion to which the mounting bolt is screwed is formed, and the housing and the mounting member are coupled by screwing the mounting bolt into the screw portion in a state where the convex portion is inserted into the concave portion. An electric motor characterized by that. The electric motor according to claim 1, wherein
An electric motor characterized in that a communication path is formed in the vicinity of the screw portion to communicate the inside and the outside of the housing. The electric motor according to claim 1 or 2,
The rotation detection sensor has an electric motor in which the case is formed in a fan shape in cross section. The electric motor according to any one of claims 1 to 3,
The electric motor comprises a brushless motor.

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