JP2018046660A - Motor unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor unit capable of reducing stress occurring on a sensor magnet.SOLUTION: A motor unit 10 includes: a rotor 14 rotatably supported around an axial line; a Hall IC 36 for detecting magnetism; a sensor magnet 38 whose magnetism is detected by the Hall IC 36; and a coupling member 18 provided rotatably together with the rotor 14. The coupling member 18 is formed with a resin material, and a slit 18H is formed on a part of the coupling member 18 adjacent to an end of the sensor magnet 38. This changes the width of the slit 18H in a cooling process at the time of insertion-forming the sensor magnet 38 into the coupling member 18. As a result, a load input into the sensor magnet 38 from the coupling member 18 is reduced, and stress occurring on the sensor magnet 38 can be reduced.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a motor unit.

  The following Patent Document 1 and Patent Document 2 disclose a motor capable of detecting the phase (rotation angle) of the rotor. In the motor described in Patent Document 1, an opening is formed in a predetermined portion of the back yoke, and the phase of the rotor can be detected by detecting the magnetic flux leaking from the opening by a sensor. It is possible. Moreover, in the motor described in Patent Document 2, the phase of the rotor can be detected by detecting the magnetic flux of the sensor magnet fitted to the bush that rotates together with the rotor by the sensor.

JP-A-6-237563 JP 2013-198275 A

  By the way, in the configuration in which the sensor magnet for detecting the rotor phase and the rotational speed is integrated with the resin holding member by insert molding or the like, the stress generated in the sensor magnet after the sensor magnet is insert molded to the holding member is reduced. It is desirable to be able to.

  An object of the present invention is to obtain a motor unit that can reduce the stress generated in the sensor magnet in consideration of the above facts.

  The motor unit according to claim 1 is provided so as to be rotatable integrally with the rotor, a rotor supported so as to be rotatable about an axis, a detection unit for detecting magnetism, a sensor magnet for detecting magnetism by the detection unit, and the rotor. And a holding member which is formed using a resin material and has a slit formed in a portion adjacent to the end portion of the sensor magnet in a state where the sensor magnet is held.

  According to the motor unit of the first aspect, when the rotor is rotated, the holding member is rotated together with the rotor. Thereby, the sensor magnet held by the holding member is rotated. The magnetism of the rotated sensor magnet is detected by the detection unit. Here, in the first aspect of the present invention, the slit is formed in the holding member adjacent to the end of the sensor magnet. Therefore, the width of the slit changes during the cooling process when the sensor magnet is insert-molded into the holding member. Thereby, the load input to the sensor magnet from the holding member is reduced, and the stress generated in the sensor magnet is reduced.

  The motor unit according to claim 2 is the motor unit according to claim 1, wherein the sensor magnet has a portion made an N-pole magnetic pole and a portion made an S-pole magnetic pole, and the sensor magnet A concave recess is formed at the boundary between the N pole magnetic pole portion and the S pole magnetic pole portion, and the slit is formed in the recess portion of the holding member. It is formed in the intrusion part.

  According to the motor unit of claim 2, in the cooling process when the sensor magnet is insert-molded into the holding member, the dimension of the portion of the holding member that has entered the recess formed in the sensor magnet changes, so that the slit The width of changes. As a result, the load that is input to the sensor magnet from the portion of the holding member that enters the recess portion formed in the sensor magnet is reduced, and the stress at the portion of the magnet where the recess portion is formed is reduced.

  The motor unit according to claim 3 is the motor unit according to claim 1 or 2, wherein a peripheral portion of a portion of the holding member where the slit is formed is in close contact with an end of the sensor magnet. It is said that.

  According to the motor unit of the third aspect, a part of the peripheral portion of the portion where the slit is formed in the holding member is a thin portion that is in close contact with the end of the magnet. Thereby, in the cooling process when the sensor magnet is insert-molded into the holding member, the thin portion which is a part of the peripheral portion of the portion where the slit is formed in the holding member is easily deformed with respect to the other part. Can do. In this way, the portion of the holding member that is in close contact with the end of the sensor magnet is a thin-walled portion that is the peripheral edge of the slit, so that the load that is input from the holding member to the sensor magnet is further reduced. Is further reduced.

  The motor unit according to the present invention has an excellent effect that the stress generated in the sensor magnet can be reduced.

It is a disassembled perspective view which decomposes | disassembles and shows a motor unit. It is a perspective view which shows the connection member provided with the sensor magnet. It is a front view which shows the connection member provided with the sensor magnet. It is a side view which shows the connection member provided with the sensor magnet. It is a rear view which shows the connection member provided with the sensor magnet. It is a side view which shows the positional relationship of a connection member and a detection apparatus. (A) is a perspective view which shows the connection member provided with the sensor magnet which concerns on a modification, (B) is the rear view which looked at the connection member shown by (A) from the rotor side.

  A motor unit according to an embodiment of the present invention will be described with reference to FIGS. In addition, the arrow Z direction, the arrow R direction, and the arrow C direction that are appropriately shown in the drawing indicate the rotation axis direction, the rotation radial direction, and the rotation circumferential direction of the rotation shaft 26 (rotor 14) of the motor unit, respectively. In addition, hereinafter, when only the axial direction, the radial direction, and the circumferential direction are indicated, the rotational axis direction, the rotational radial direction, and the rotational circumferential direction of the rotary shaft 26 (rotor 14) are indicated unless otherwise specified.

  As shown in FIG. 1, the motor unit 10 of the present embodiment is a power seat motor unit used for operating a power seat of a vehicle as an example. The motor unit 10 includes a stator 12, a rotor 14, and a brush holder 16 that supports a brush (not shown). Further, the motor unit 10 includes a connecting member 18 that connects the rotor 14 and other members and is formed integrally with the sensor magnet 38, and a detection device 20 that detects the phase of the rotor 14.

(Configuration of stator 12)
The stator 12 includes a motor yoke 22 formed in a substantially bottomed cylindrical shape. A plurality of stator magnets 24 are fixed to the inner peripheral surface of the motor yoke 22, and the plurality of stator magnets 24 are arranged at equal intervals along the circumferential direction.

(Configuration of rotor 14)
Most of the rotor 14 is disposed in the motor yoke 22, and the rotor 14 includes a rotating shaft 26, a stator core 28, and a commutator 30.

  The rotating shaft 26 is arranged coaxially with the motor yoke 22, and the end of the rotating shaft 26 on the other axial side (opposite to the arrow Z direction) is connected to the motor yoke 22 via a bearing member (not shown). It is rotatably supported at the bottom. Further, a portion on one side in the axial direction of the rotary shaft 26 is rotatably supported via a bearing member (not shown) supported by the brush holder 16. Moreover, the axial direction one end part of the rotating shaft 26 is made into the connection member fixing | fixed part 26A to which the connection member 18 is fixed.

  The stator core 28 is fixed to the rotary shaft 26 and is disposed in the motor yoke 22. In addition, the stator core 28 includes a plurality of teeth portions that extend radially outward in the radial direction and are arranged at equal intervals along the circumferential direction. The coils formed by winding the windings are respectively formed.

  The commutator 30 is fixed to the axially one side portion of the rotating shaft 26 by press fitting. The commutator 30 includes a plurality of commutator pieces 30 </ b> A, and the commutator pieces 30 </ b> A are concentrically disposed on the outer peripheral surface of the commutator 30. Moreover, the terminal part of the coil | winding which forms a coil is electrically connected to each commutator piece 30A of the commutator 30. FIG.

(Configuration of brush holder 16)
The brush holder 16 is formed using an insulating material. The brush holder 16 is formed in a cylindrical shape, and a main body portion 16A in which a commutator 30 is disposed on an inner peripheral portion, and a main body portion 16A. And a connector portion 16B that extends outward in the radial direction and to which a mating connector (not shown) is connected. A pair of brushes (not shown) is supported on the main body portion 16A. The pair of brushes are in sliding contact with the commutator piece 30 </ b> A of the commutator 30, so that the current supplied to the coil formed around the teeth portion of the stator core 28 is switched. The brush holder 16 is provided with a terminal 32 that connects a terminal supported by the mating connector and a brush or a detection device 20 described later.

(Configuration of the detection device 20)
As shown in FIG. 1, the detection device 20 is provided between the brush holder 16 and an end bracket 37 attached to the brush holder 16, and the detection device 20 is a circuit formed in a rectangular plate shape. The circuit board 34 is configured to include a Hall IC 36 as a detection unit attached to the circuit board 34. The circuit board 34 extends with the axial direction as the thickness direction, and a circular insertion hole 34 </ b> A through which the rotary shaft 26 is inserted is formed in the middle part of the circuit board 34 in the longitudinal direction. In addition, a Hall IC 36 is attached to the peripheral edge portion of the insertion hole 34A on one surface in the axial direction of the circuit board 34 by soldering or the like. The Hall IC 36 is disposed to face the sensor magnet 38 supported by the connecting member 18 in the axial direction. The Hall IC 36 detects the magnetism of the sensor magnet 38. Further, when the magnetic strength (magnetic flux) detected by the Hall IC 36 exceeds a predetermined value, the Hall IC 36 outputs an ON signal.

(Configuration of sensor magnet 38)
As shown in FIGS. 2 and 4, the sensor magnet 38 is integrally formed with the connecting member 18 so as to be integrally rotatable with the connecting member 18. The sensor magnet 38 is integrated with the connecting member 18 by setting the sensor magnet 38 in a predetermined mold and injecting a resin material forming the connecting member 18 into the mold and cooling the sensor magnet 38. (Integrated with the connecting member 18 by insert molding).

  Specifically, the sensor magnet 38 is a ring magnet formed in a cylindrical shape and disposed coaxially with the rotating shaft 26 (see FIG. 1). In addition, a portion on one side in the radial direction of the sensor magnet 38 is an N-pole portion 38N that is an N-pole magnetic pole, and a portion on the other radial side of the sensor magnet 38 is an S-pole that is an S-pole. The pole portion is 38S. In the present embodiment, the peripheral portion of the boundary 38A between the N pole portion 38N and the S pole portion 38S in the sensor magnet 38, that is, the boundary portion 38B between the N pole portion 38N and the S pole portion 38S (hereinafter, the boundary portion 38B). (Referred to as “magnetic pole boundary 38B”) is formed with a concave recess 38C in which the detection device 20 side (the other side in the axial direction) is opened. As a result, as shown in FIG. 6, the axial distance L1 between the magnetic pole boundary 38B (the portion where the recess 38C is formed) of the sensor magnet 38 and the Hall IC 36 is excluded from the magnetic pole boundary 38B of the sensor magnet 38. The distance is longer than the axial distance L2 between the portion 38D and the Hall IC 36. In addition, since the sensor magnet 38 of this embodiment has a pair of magnetic poles (N pole part 38N and S pole part 38S), the sensor magnet 38 is formed with two depressions 38C. In the present embodiment, the depth D of the recessed portion 38C is substantially constant along the circumferential direction.

(Detailed configuration of the connecting member 18)
Next, the structure of the connection member 18 which is the principal part of this embodiment is demonstrated.

  As shown in FIGS. 2 to 5, the connecting member 18 as a holding member is formed using a resin material, and the connecting member 18 is a sensor magnet fixing portion to which the sensor magnet 38 is fixed (held). 18A and three transmission protrusions 18B projecting from one end in the axial direction of the sensor magnet fixing portion 18A.

  As shown in FIG. 2 to FIG. 4, the sensor magnet fixing portion 18 </ b> A includes a disc portion 18 </ b> E formed in a disc shape extending in the radial direction with the axial direction as the thickness direction, and the axial center of the disc portion 18 </ b> E. A cylindrical portion 18F formed in a cylindrical shape protruding from the portion toward the other side in the axial direction. An engagement hole 18C is formed in the axial center of the cylindrical portion 18F. Then, the connecting member fixing portion 26 </ b> A (see FIG. 1) of the rotating shaft 26 is engaged with the engaging hole 18 </ b> C so that the connecting member 18 is fixed to the end portion on the one axial side of the rotating shaft 26. It has become.

  As shown in FIGS. 2, 4, and 5, the sensor magnet fixing portion 18 </ b> A includes a pair of indentation portion placement portions 18 </ b> G that are respectively disposed in a pair of indentation portions 38 </ b> C formed in the sensor magnet 38. ing. On both end sides in the circumferential direction of the in-cavity arrangement portion 18G, slits 18H that are open on the other axial side when viewed from the outside in the radial direction are formed. Further, both end portions in the circumferential direction of the in-cavity arrangement portion 18G are thin-walled portions 18I that are in close contact with the end surfaces in the circumferential direction of the portion 38D excluding the magnetic pole boundary portion 38B in the sensor magnet 38. The thickness T2 (dimension in the circumferential direction) of the thin-walled portion 18I is set to be thinner than the thickness T1 (dimension in the circumferential direction) of the central portion in the circumferential direction of the in-dent placement portion 18G. Further, the thin portion 18I of one indentation portion arrangement portion 18G and the thin portion 18I of the other indentation portion arrangement portion 18G extend along the inner peripheral surface of the portion 38D of the sensor magnet 38 excluding the magnetic pole boundary portion 38B. It is connected via the connecting wall 18J.

(Operation and effect of this embodiment)
Next, the operation and effect of this embodiment will be described.

  As shown in FIG. 1, in the motor unit 10 of the present embodiment, a brush (not shown) provided in the brush holder 16 is in sliding contact with the commutator 30, and is applied to a plurality of coils constituting a part of the rotor 14. When the energization is switched, the rotor 14 rotates. Thereby, the member which comprises a part of vehicle power seat is rotated via the connection member 18 fixed to the rotating shaft 26 of the rotor 14, and the power seat of a vehicle is operated.

  When the rotor 14 is rotated, the sensor magnet 38 supported by the connecting member 18 is rotated. When the magnetism of the sensor magnet 38 is detected by the Hall IC 36 and the magnetic strength (magnetic flux) detected by the Hall IC 36 exceeds a predetermined value, an ON signal is output from the Hall IC 36. And the rotation angle of the rotating shaft 26 is calculated by counting this ON signal.

  Here, as shown in FIGS. 2, 4, and 5, in the connecting member 18 of the present embodiment, a slit 18 </ b> H is formed in the indented portion arrangement portion 18 </ b> G of the sensor magnet fixing portion 18 </ b> A. Therefore, the width of the slit 18H can be changed in the cooling process when the sensor magnet 38 is insert-molded into the connecting member 18. Thereby, the load input to the sensor magnet 38 from the indented portion arrangement portion 18G of the connecting member 18 (the circumferential load input from the indentation portion arrangement portion 18G to the portion 38D of the sensor magnet 38 excluding the magnetic pole boundary portion 38B). Can be reduced, and bending stress generated in the portion of the sensor magnet 38 where the recess 38C is formed can be reduced.

  Further, in the present embodiment, both end portions in the circumferential direction of the indentation portion arrangement portion 18G of the connecting member 18 are the thin-walled portions 18I that are in close contact with the circumferential end surface of the portion 38D excluding the magnetic pole boundary portion 38B of the sensor magnet 38. ing. Thereby, in the cooling process when the sensor magnet 38 is insert-molded into the connecting member 18, the thin-walled portion 18I of the recessed portion placement portion 18G is easily deformed with respect to the circumferential central portion of the recessed portion placement portion 18G. Can do. As described above, by setting the portion closely contacting the sensor magnet 38 in the in-cavity placement portion 18G as the thin portion 18I, the load input from the in-well placement portion 18G to the sensor magnet 38 can be further reduced. . As a result, it is possible to further reduce the stress generated in the portion where the recess is formed in the sensor magnet.

  Furthermore, in the present embodiment, the thin portion 18I of one indentation portion arrangement portion 18G and the thin portion 18I of the other indentation portion arrangement portion 18G are on the inner peripheral surface of the portion 38D of the sensor magnet 38 excluding the magnetic pole boundary portion 38B. It is connected via a connecting wall portion 18J extending along. As described above, by configuring the portion 38D protruding from the magnetic pole boundary portion 38B to be supported from the radially inner side by the connecting wall portion 18J, it is possible to improve the resistance of the sensor magnet 38 to the impact. Further, this configuration is particularly useful when the sensor magnet 38 is a ferrite magnet.

  In the present embodiment, an example in which a concave depression 38 </ b> C that is open on the other side in the axial direction is formed in a magnetic pole boundary 38 </ b> B that is a boundary 38 </ b> B between the N pole 38 </ b> N and the S pole 38 </ b> S in the sensor magnet 38. Although described, the present invention is not limited to this. For example, as shown in FIGS. 7A and 7B, in the configuration in which the detection device 20 is disposed on the radially outer side of the sensor magnet 38, the N pole portion 38N and the S pole portion 38S of the sensor magnet 38 It is also possible to form a concave depression 38C having a radially outer side opened in the magnetic pole boundary 38B, which is the boundary 38B. Here, in the sensor magnet 38 and the connecting member 18 shown in FIGS. 7A and 7B, portions corresponding to the sensor magnet 38 and the connecting member 18 shown in FIG. 2 are shown in FIG. The same reference numerals as those of the sensor magnet 38 and the connecting member 18 are used.

  In addition, although the example demonstrated above demonstrated the example which formed the slit 18H in the recessed part arrangement | positioning part 18G, this invention is not limited to this. The position where the slit 18H is provided may be appropriately set in consideration of the dimensional change amount of each part in the process of cooling the connecting member 18.

  Although one embodiment of the present invention has been described above, the present invention is not limited to the above, and various modifications other than the above can be implemented without departing from the spirit of the present invention. Of course.

10 Motor unit 14 Rotor 18 Connecting member (holding member)
18H Slit 18I Thin part 38 Sensor magnet 38C Depression part 36 Hall IC (detection part)

Claims (3)

A rotor supported rotatably about an axis,
A detector for detecting magnetism;
A sensor magnet in which magnetism is detected by the detection unit;
A holding member that is provided so as to be integrally rotatable with the rotor and is formed using a resin material, and in which the sensor magnet is held, a slit is formed in a portion adjacent to an end of the sensor magnet,
Motor unit with The sensor magnet has an N-pole magnetic pole part and an S-pole magnetic pole part,
In the sensor magnet, a concave depression is formed at the boundary between the portion made the N-pole magnetic pole and the portion made the S-pole magnetic pole,
The motor unit according to claim 1, wherein the slit is formed in a portion of the holding member that enters the recess.   3. The motor unit according to claim 1, wherein a part of a peripheral edge portion of the holding member where the slit is formed is a thin portion that is in close contact with an end portion of the sensor magnet.

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