JP2019088187A - motor - Google Patents

Abstract

To provide an inner rotor type motor which can hold a rotation position and has a simple structure.SOLUTION: An inner rotor type motor 1 includes: an armature assembly 1b; a frame assembly 1a; and a biasing structure 40. The armature assembly 1b has a rotary shaft 2 and an armature part 4 attached to the rotary shaft 2. The frame assembly 1a houses the armature part 4 therein. The frame assembly 1a pivotally supports the rotary shaft 2 with a first bearing part 21 located at one axial side of the armature part 4 and a second bearing part 26 located at the other axial side of the armature part 4. The biasing structure 40 biases the rotary shaft 2 in a direction away from the second bearing part 26 between the second bearing part 26 and the armature part 4. A pressing part 2a provided at the armature assembly 1b is pressed to the first bearing part 21.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an inner rotor type motor, and more particularly to an inner rotor type motor capable of holding a rotational position.

  Inner rotor type motors are often used as drive sources in, for example, office equipment and home appliances. Among such inner rotor type motors, there are those used in applications where it is necessary to maintain the rotational position of equipment attached to the rotation shaft of the motor.

  Patent Document 1 below discloses a structure of an inner rotor type electric motor in which braking members on the fixed side and the movable side for performing a braking action are incorporated in a casing so that a stop holding torque can be obtained when power is not supplied. It is done. In this structure, the brake is activated in the non-energized state by the attraction force generated by the position of the magnetic center of the magnet on the casing side and the axial center of the rotor being shifted.

  In Patent Document 2 below, a multi-pole magnetized magnet having a plurality of magnetic poles is provided on one of the rotor side and the stator side on the outer side of the motor frame, and a plurality of magnetized portions and hysteresis are provided on the other to face it. A structure of an apparatus is disclosed in which a braking force and a holding force can be obtained by providing a multipolar magnetized magnet in which both parts are formed.

  Patent Document 3 below discloses, in a valve opening / closing device used for an exhaust gas recirculation device or the like, a structure having a valve-closing return spring in the device.

  Patent Document 4 below discloses the structure of a spindle drive device having a built-in brake device, in which a coil spring for braking is disposed on the axially outer side of the motor.

JP 2001-320856 A Japanese Patent Application Laid-Open 10-150762 JP 2011-211825 A German Patent Application Publication DE 102008061117 A1

  By the way, in a device (set) in which a member is displaced using the inner rotor type motor as described above, when it is necessary to hold the rotational position of the motor corresponding to the position of the member, It is common to provide a retention mechanism near the part that will However, particularly in a set having a configuration in which the motor rotation speed is reduced by the reduction mechanism including gears and the like to displace the members, when the holding mechanism is provided after passing the reduction mechanism from the motor, the holding mechanism is larger Holding power must be exerted. Therefore, in such a case, it is necessary to provide a holding mechanism having a large size and structure, and the set using the inner rotor type motor becomes large or the manufacturing cost becomes high.

  As described in Patent Document 1, when the brake mechanism is provided inside the motor, the holding force of the motor is amplified by the reduction ratio, so the holding mechanism can be simplified. However, the structure described in Patent Document 1 has a problem that the number of parts is large, and a partition plate is provided inside the motor, resulting in an increase in manufacturing cost. Furthermore, since only the magnetic thrust force of the rotor is the force that generates the frictional holding force at the time of deenergization, it is difficult to obtain a high holding force, and a strong magnet should be used to obtain a high holding force. There is an issue at cost disadvantage that it is inevitable.

  The structure as described in Patent Document 2 has a problem that it is difficult to handle because a magnet or the like is provided on the outside of the motor. In addition, it is necessary to configure one of the magnets with uneven thickness, and there is a problem in manufacturing particularly when the size is reduced. Further, by forming the multipolar-magnetized magnet on one side on the rotating side and one on the stationary side, there is a concern of vibration in the thrust direction.

  Patent Document 3 and Patent Document 4 do not disclose effective solutions to the problems described above.

  The present invention has been made to solve such problems, and it is an object of the present invention to provide an inner rotor type motor capable of holding a rotational position with high holding power with a simple and compact configuration.

  In order to achieve the above object, according to one aspect of the present invention, a motor includes an armature assembly having a rotating shaft and an armature portion, a first bearing portion positioned on one side in the axial direction, and the other side in the axial direction Of the second bearing, the frame holding the first bearing and the second bearing, the pressing part provided on the armature assembly, and the pressing part from the second bearing to the first bearing The slide washer includes a coil spring for pressing toward the axis, and a slide washer fitted to the rotary shaft, and the slide washer is rotatable around the rotary shaft and is axially displaceable. A commutator supporting a coil spring is fixed to a portion between the bearing portion and the armature portion.

  Preferably, the coil spring is attached to the commutator so as to rotate with the commutator, and the coil spring is provided with a pressing member axially displaceably provided between the coil spring and the second bearing portion. Press against the second bearing.

Preferably, the motor includes a washer disposed between the armature portion and the second bearing portion, and in the axial direction, the sliding washer is disposed between the armature portion and the second bearing portion; Located between the second bearing portion and in the axial direction, the coil spring is located between a washer disposed between the armature portion and the second bearing portion and the armature portion.
Preferably, the motor includes a second sliding washer and a second sliding washer, wherein the sliding washer is a first sliding washer, and the washer is disposed between the armature portion and the first bearing portion in the axial direction. The second sliding washer is located between the washer disposed between the armature and the first bearing and the first bearing.

Preferably, the washer disposed between the armature portion and the first bearing portion is rotatable with the rotation shaft.
Preferably, the pressing portion is pressed against the first bearing via the second sliding washer.
Preferably, the washer disposed between the armature portion and the second bearing portion is axially displaceable.

According to another aspect of the present invention, a motor includes an armature assembly having a rotating shaft and an armature portion, a first bearing portion positioned on one side in the axial direction, and a first portion positioned on the other side in the axial direction. 2) A bearing that holds the bearing, the first bearing and the second bearing, a pressing part provided on the armature assembly, and an urging that presses the pressing part from the second bearing toward the first bearing And, in axial direction, the biasing structure comprises opposing first and second permanent magnets, the same poles of the first and second permanent magnets being opposed A support member for supporting the biasing structure is fixed to a portion of the rotation shaft between the second bearing portion and the armature portion, and the first permanent magnet rotates with the support member. Located on the support member, the second permanent magnet rotates with the support member As such, and displaceable in the axial direction, are arranged on the support member, it is pressed against the second bearing portion by the urging structure.
Preferably, the support member is a commutator.

  According to still another aspect of the present invention, the motor is positioned on the armature assembly having the rotating shaft and the armature portion, the first bearing portion positioned on one side in the axial direction, and the other side on the axial direction. The second bearing portion, the frame for holding the first bearing portion and the second bearing portion, the pressing portion provided on the armature assembly, and the pressing portion are pressed from the second bearing portion toward the first bearing portion A biasing structure, and in the axial direction, the biasing structure comprises opposing first and second permanent magnets, the same poles of the first and second permanent magnets being opposed A commutator supporting the biasing structure is fixed to a portion of the rotary shaft between the second bearing portion and the armature portion.

  Preferably, the motor comprises a sliding washer fitted in the rotation axis, the sliding washer being rotatable about the rotation axis and axially displaceable.

  Preferably, the motor includes a second sliding washer with the sliding washer as a first sliding washer, and the pressing portion is pressed against the first bearing via the second sliding washer.

  Preferably, the motor comprises a washer disposed between the armature portion and the first bearing portion, and the washer disposed between the armature portion and the first bearing portion is rotatable with the rotation shaft.

  According to these inventions, it is possible to provide an inner rotor type motor capable of holding the rotational position with high holding power with a simple and compact configuration.

FIG. 1 is a side sectional view showing an inner rotor type motor according to a first embodiment of the present invention. It is a side sectional view showing an inner rotor type motor concerning a 2nd embodiment. It is a side sectional view showing an inner rotor type motor concerning a 3rd embodiment. It is the side view which looked at the commutator concerning a 3rd embodiment from the direction of an axis.

  Hereinafter, an inner rotor type motor according to an embodiment of the present invention will be described.

  First Embodiment

  FIG. 1 is a side sectional view showing an inner rotor type motor 1 according to a first embodiment of the present invention.

  In FIG. 1, the left and right direction may be referred to as an axial direction.

  As shown in FIG. 1, an inner rotor type motor (hereinafter sometimes referred to simply as a motor) 1 roughly includes a frame assembly 1a and an armature set rotatably supported relative to the frame assembly 1a. And 3D (hereinafter, may be simply referred to as an amateur) 1b. The motor 1 is a so-called brushed DC motor.

  The amateur assembly 1 b includes a rotating shaft (shaft) 2, an amateur unit 4, a commutator 30 and the like.

  The amateur part 4 is attached to the rotating shaft 2. The armature unit 4 includes an armature core 5 having a plurality of salient poles projecting in the radial direction, a winding (not shown) wound around each salient pole, and the like.

  The commutator 30 is provided in the vicinity of one end of the rotation shaft 2 (near the bottom). The commutator 30 has a commutator piece (not shown) connected to the winding.

  The frame assembly 1a comprises a frame 10, a bracket 12, a plate 13, a magnet 8 and the like.

  The frame 10 has a cylindrical shape in which one end (a left part in FIG. 1; sometimes referred to as a top) is closed so that the rotation shaft 2 protrudes. The opening of the other end of the frame 10 (the end on the right in FIG. 1; sometimes referred to as the bottom) is closed by the plate 13. The armature 1b is housed inside the frame 10, and the bottom of the frame 10 is constituted by the plate 13, whereby a housing for housing the amateur part 4 inside is constituted. One end of the rotation shaft 2 projects from the top of the frame 10. The power of the motor 2 can be taken out from the protruding portion of the rotating shaft 2.

  A first bearing portion 21 is held at the center of the top of the frame 10. A second bearing portion 26 is held at a central portion of the plate 13. That is, the first bearing portion 21 is located on one side of the armature portion 4 in the axial direction, and the second bearing portion 26 is located on the other side of the armature portion 4 in the axial direction. The rotating shaft 2 is supported by two first bearings 21 and second bearings 26 (sometimes referred to as bearings 21 and 26). The armature 1 b is rotatably held relative to the frame 10 by bearings 21 and 26.

  The bracket unit 20 is configured by the plate 13, the bracket 12, the second bearing portion 26, and a terminal or a brush not shown. That is, the bracket 12 is attached to the inside of the plate 13. The bracket 12 holds a terminal to which an external current is supplied. A brush is connected to the tip of the terminal. The brush is arranged such that the tip contacts the commutator 30 of the armature 1b. Electric power is supplied to the commutator bar on the commutator 30 via the brush, whereby the motor 1 is driven.

  In the present embodiment, the motor 1 has a biasing structure 40 that biases the rotating shaft 2 in one axial direction. The biasing structure 40 is provided between the second bearing portion 26 and the armature portion 4 inside the frame assembly portion 1 a of the motor 1. A pressing portion 2 a having a diameter larger than that of a portion supported by the first bearing portion 21 is provided at a portion of the rotating shaft 2 between the armature portion 4 and the first bearing portion 21. A washer 51 is disposed closer to the first bearing portion 21 than the pressing portion 2a. The washer 51 is rotatable with the rotating shaft 2. The washer 51 may be press-fitted to the rotating shaft 2 or may be loosely fitted to the rotating shaft 2. The biasing structure 40 biases the rotation shaft 2 in a direction away from the second bearing portion 26 (left direction in FIG. 1). As a result, the pressing portion 2 a is pressed together with the washer 51 toward the first bearing portion 21.

  The biasing structure 40 includes a coil spring 41 and a washer (an example of a pressing member) 56. The coil spring 41 is disposed between the second bearing portion 26 and the commutator 30 functioning as a support member when the rotary shaft 2 is biased. The washer 56 is disposed between the coil spring 41 and the second bearing portion 26. The washer 56 is loosely fitted on the rotary shaft 2 and is disposed so as to be axially displaceable.

  The coil spring 41 is disposed such that its coil axis substantially coincides with the axial direction. The coil spring 41 is attached between the commutator 30 and the washer 56 in a compressed state. In the present embodiment, a groove 33 in which a part of the coil spring 41 is embedded in the axial direction is formed on the end face of the commutator 30 on the second bearing 26 side. One axial end of the coil spring 41 is embedded in the groove 33. As described above, since the coil spring 41 is disposed in the groove 33, the space required for arranging the coil spring 41 inside the motor 1 can be saved, and the axial dimension of the motor 1 can be reduced. be able to. Since the coil spring 41 is thus attached to the commutator 30, it rotates together with the rotating shaft 2 and the commutator 30.

  The coil spring 41 tries to extend from the compressed state between the commutator 30 and the washer 56. The restoring force acts to increase the distance between the commutator 30 and the washer 56. That is, the coil spring 41 presses the pressing portion 2 a together with the washer 51 toward the first bearing portion 21 by a restoring force. Also, the coil spring 41 presses the washer 56 toward the second bearing portion 26 by a restoring force.

  A sliding washer 61 is disposed between the first bearing portion 21 and the washer 51. The sliding washer 61 is gently fitted on the rotating shaft 2. The slide washer 61 is rotatable around the rotation shaft 2 with respect to the rotation shaft 2, is rotatable around the rotation shaft 2 with respect to the first bearing portion 21, and is axially displaceable. The washer 51 is pressed against the first bearing 21 via the sliding washer 61. Not only one sliding washer 61 but a plurality of sliding washers 61 may be used.

  A sliding washer 66 is disposed between the second bearing portion 26 and the washer 56. The sliding washer 66 is gently fitted to the rotating shaft 2. The slide washer 66 is rotatable around the rotation shaft 2 with respect to the rotation shaft 2, is rotatable around the rotation shaft 2 with respect to the second bearing portion 26, and is axially displaceable. The washer 56 is pressed against the second bearing portion 26 via the sliding washer 66. Not only one sliding washer 61 but a plurality of sliding washers 61 may be used.

  The bearings 21 and 26 are, for example, metal bearings (oil-impregnated bearings). The end surface of each of the bearings 21 and 26 on the side of the armature portion 4 has a smooth surface perpendicular to the rotation shaft 2. The sliding washer 61 can slide around the rotation shaft 2 with respect to the end face of the first bearing portion 21 and the washer 51 while being sandwiched between the first bearing portion 21 and the washer 51. Similarly, the sliding washer 66 can slide around the rotation shaft 2 with respect to the end face of the second bearing portion 26 and the washer 56 while being sandwiched between the second bearing portion 26 and the washer 56. It is.

  As described above, in the present embodiment, the biasing structure 40 using the coil spring 41 is disposed on the armature 1 b side, and the biasing structure 40 causes the first bearing 21 and the second bearing 26 to move. Axial thrust load is applied. Thus, the holding torque for the rotation of the armature 1b can be obtained by the applied load, the friction coefficient of the surface receiving the thrust load, and the frictional force corresponding to the area of the surface. That is, between the end face of the first bearing 21 and the sliding washer 61, between the sliding washer 61 and the washer 51, between the washer 56 and the sliding washer 66, the sliding washer 66 and the second bearing 26 Between the end face and the end face, holding torque by static friction force and holding torque by loss torque can be obtained. In the state where the rotational torque is not applied, the rotational position of the armature 1b can be held against the external force applied to the rotary shaft 2 under the influence of the holding torque.

  When the motor 1 rotates, the sliding washer 61 slides around the rotation shaft 2 with respect to each of the end face of the first bearing portion 21 and the washer 51. In addition, the sliding washer 66 slides around the rotation shaft 2 with respect to each of the end face of the second bearing portion 26 and the washer 56. Therefore, the motor 1 can rotate smoothly. The members sliding with respect to the sliding washers 61 and 66 may not be all of the bearings 21 and 26 and the washers 51 and 56, and may be appropriately changed according to the rotation condition of the motor 1.

  The holding torque of the motor 1 can be generated with a simple configuration by providing the coil spring 41, the washers 51 and 56, the sliding washers 61 and 66, etc. inside the motor 1. Since the configuration of the motor 1 can be simplified, the manufacturing cost of the motor 1 can be reduced. In many applications where the motor 1 is decelerated using a reduction gear etc., compared to the case where a holding mechanism is provided after decelerating, the same holding force is generated by merely generating a small holding torque on the motor 1 side. be able to. Therefore, the configuration of the system using the motor 1 can be miniaturized or simplified. Further, the reliability of the system using the motor 1 can be enhanced.

  Second Embodiment

  The basic configuration of the motor in the second embodiment is the same as that in the first embodiment, and thus the description thereof will not be repeated. About the member which has a function similar to 1st Embodiment, the same code | symbol as 1st Embodiment may be attached | subjected, and specific description may be abbreviate | omitted. The biasing structure is configured to include a coil spring and a washer as in the first embodiment. The second embodiment is different from the first embodiment in the position at which the biasing structure is provided, the direction in which the biasing structure, and the like are provided. In the second embodiment, the coil spring is provided on the fixed body side, that is, on the frame assembly side.

  FIG. 2 is a side sectional view showing an inner rotor type motor 201 according to a second embodiment.

  In FIG. 2, the left and right direction may be referred to as an axial direction. The motor 201 includes a frame assembly 201a and an armature 201b.

  As shown in FIG. 2, in the frame assembly 201 a, a second bearing portion 226 is held at the center of the top of the frame 10. Conversely, the first bearing portion 221 is held at the central portion of the plate 13. The rotation shaft 2 of the armature 201 b is axially supported by the first bearing portion 221 and the second bearing portion 226.

  Inside the top of the frame 10, a fixing member 250 is fixed. Similar to the groove 33 in the first embodiment described above, the fixing member 250 is formed with a groove 253 in which the coil spring 41 is embedded. The groove portion 253 is formed in an annular shape substantially coaxial with the rotation shaft 2 so as to open toward the first bearing portion 221.

  One axial end of the coil spring 41 is embedded in the groove 253. That is, the coil spring is attached to the frame assembly 201a so as not to rotate with respect to the frame assembly 201a.

  In the second embodiment, the armature 201a has a commutator 230 and a support member 235, which are different in configuration from the first embodiment.

  Unlike the commutator 30 in the first embodiment, the commutator 230 does not have the groove 33 and the coil spring 41 is not embedded. The commutator 230 functions as a pressing portion that is pressed toward the first bearing portion 221 when the rotary shaft 2 is biased as described later. A washer 51 is disposed closer to the first bearing portion 221 than the commutator 230. The washer 51 is rotatable with the rotating shaft 2. The washer 51 may be press-fitted to the rotating shaft 2 or may be loosely fitted to the rotating shaft 2.

  The support member 235 is disposed between the armature portion 4 and the second bearing portion 226. The support member 235 includes a thrust holder 238 protruding from the armature portion 4 to the top side, and a bearing member 236.

  The bearing member 236 is, for example, a sintered oil-impregnated metal. The thrust holder 238 is made of, for example, a resin, and is connected to the armature unit 4. The bearing member 236 is press-fitted to the rotating shaft 2. The thrust holder 238 and the bearing member 236 rotate with the rotating shaft 2. The thrust holder 238 has a wedge shape that opens toward the second bearing portion 226, and a bearing member 236 is disposed therein. Since the outer periphery of the bearing member 236 is covered by the thrust holder 238, scattering of the oil contained in the bearing member 236 by centrifugal force when the armature 201b rotates is prevented.

  In the second embodiment, the biasing structure 240 includes a coil spring 41 attached to the fixing member 250 and a washer (an example of a pressing member) 56. The washer 56 is disposed between the coil spring 41 and the bearing member 236 of the support member 235. The washer 56 is loosely fitted on the rotary shaft 2 and is disposed so as to be axially displaceable. The coil spring 41 is compressed and attached between the support member 235 and the fixing member 250 (that is, between the support member 235 and the second bearing portion 226).

  The biasing structure 240 biases the rotating shaft 2 in a direction away from the second bearing portion 226 (rightward in FIG. 2) by the restoring force of the coil spring 41. That is, the coil spring 41 presses the commutator 230 together with the washer 51 toward the first bearing portion 221. Also, the coil spring 41 presses the washer 56 toward the bearing member 236.

  A sliding washer 61 is disposed between the first bearing portion 221 and the washer 51 as in the first embodiment. That is, the commutator 230 is pressed against the first bearing portion 221 via the sliding washer 66. The sliding washer 61 is slidable around the rotation shaft 2 with respect to the end face of the first bearing portion 221 and the washer 51 in a state of being sandwiched between the first bearing portion 221 and the washer 51. Further, a sliding washer 66 is disposed between the bearing member 236 and the washer 56 as in the first embodiment. The sliding washer 66 is slidable around the rotation axis 2 with respect to the end face of the bearing member 236 and the washer 56 while being sandwiched between the bearing member 236 and the washer 56. That is, in the state where the washers 51 and 56 are respectively biased by the biasing structure 240, the sliding washers 61 and 66 are between the first bearing portion 221 and the washer 51 or between the bearing member 236 and the washer 56. The same functions as in the first embodiment.

  Thus, in the second embodiment, the biasing structure 240 using the coil spring 41 is disposed on the side of the frame assembly 201 a, and the first bearing portion 221 and the bearing member 236 are arranged by the biasing structure 240. And an axial thrust load is applied. Therefore, between the end face of the first bearing portion 221 and the sliding washer 61, between the sliding washer 61 and the washer 51, between the washer 56 and the sliding washer 66, and the end face of the sliding washer 66 and the bearing member 236 Between the above, the holding torque by the static friction force and the holding torque by the loss torque can be obtained. Therefore, also in the second embodiment, the same effect as that of the first embodiment can be obtained.

  In the second embodiment, since the coil spring 41 is disposed on the fixed body side, the commutator 230 can have a simpler configuration.

  Third Embodiment

  The basic configuration of the motor in the third embodiment is the same as that in the first embodiment, and thus the description thereof will not be repeated. About the member which has a function similar to 1st Embodiment, the same code | symbol as 1st Embodiment may be attached | subjected, and specific description may be abbreviate | omitted. The third embodiment is different from the first embodiment in that the biasing structure is configured using a pair of biasing magnets.

  FIG. 3 is a side sectional view showing an inner rotor type motor 301 according to a third embodiment.

  In FIG. 3, the left and right direction may be referred to as an axial direction. As shown in FIG. 3, the motor 301 has a frame assembly 1a and an armature 301b which are configured in the same manner as in the first embodiment. In the motor 301, the structure on the top side (left side in FIG. 3) of the armature unit 4 is the same as that of the first embodiment.

  In the amateur 301 b, a commutator 330 is used instead of the commutator 30. The commutator 330 is fixed to the rotating shaft 2.

  In the third embodiment, the motor 1 has a biasing structure 340 for biasing the rotating shaft 2 in one axial direction. The biasing structure 340 is provided between the second bearing 26 and the armature 4 inside the frame assembly 1 a. Similar to the biasing structure 40 in the first embodiment, the biasing structure 340 biases the rotating shaft 2 in a direction away from the second bearing portion 26 (leftward in FIG. 3). As a result, the pressing portion 2 a is pressed together with the washer 51 toward the first bearing portion 21.

  More specifically, the biasing structure 340 is disposed between the commutator 330 and the second bearing portion 26. The commutator 330 functions as a support member when the biasing structure 340 biases the rotating shaft 2.

  The biasing structure 340 includes a first biasing magnet 341 disposed on the commutator 330 side, and a second biasing magnet 342 disposed on the second bearing portion 26 side of the first biasing magnet 341. There is. Each of the first biasing magnet 341 and the second biasing magnet 342 is a permanent magnet magnetized so as to be divided into two poles in the axial direction.

  The commutator 330 has a protrusion 333 that protrudes in the axial direction from the end face on the second bearing 26 side. The first biasing magnet 341 and the second biasing magnet 342 are disposed in the commutator 330 such that the projecting portion 333 penetrates a hole provided at the central portion. The first biasing magnet 341 and the second biasing magnet 342 are arranged such that the same poles face each other.

  FIG. 4 is a side view of the commutator 330 according to the third embodiment as viewed from the axial direction.

  As shown in FIG. 4, the commutator 330 is formed in a substantially cylindrical shape, and is connected to a cylindrical portion 330 a having a side circumferential surface on which a commutator piece (not shown) is disposed, and to each commutator piece And a commutator riser 330b on which the coil wire is wound. In the third embodiment, the protruding portion 333 protruding from the cylindrical portion 330a has, for example, a polygonal prism shape such as a hexagonal shape. The first biasing magnet 341 and the second biasing magnet 342 conform to the shape of the projecting portion 333 and have a polygonal hole such as, for example, a hexagonal shape sized so as to be gently fitted into the projecting portion 333 There is. Thus, both the first biasing magnet 341 and the second biasing magnet 342 are attached to the commutator 330 so as to be axially displaceable and rotatable with the commutator 330. The first biasing magnet 341 may be press-fit into the projecting portion 333.

  Returning to FIG. 3, the first biasing magnet 341 is supported by the end face of the cylindrical portion 330 a of the commutator 330. Further, a sliding washer 66 is disposed between the second biasing magnet 342 and the end face of the second bearing portion 26.

  Since the first biasing magnet 341 and the second biasing magnet 342 are disposed such that the same poles face each other, a magnetic repulsive force acts between them. The biasing structure 340 presses the pressing portion 2 a and the washer 51 toward the first bearing portion 21 via the sliding washer 61 by the repulsive force. In addition, the biasing structure 340 presses the second biasing magnet 342 itself toward the second bearing via the sliding washer 66 by the repulsive force. The end face on the second bearing 26 side of the second biasing magnet 342 has a smooth surface perpendicular to the axial direction.

  The sliding washer 61 can slide around the rotation shaft 2 with respect to the end face of the first bearing portion 21 and the washer 51 while being sandwiched between the first bearing portion 21 and the washer 51. In addition, the sliding washer 66 is sandwiched between the second bearing portion 26 and the second biasing magnet 342, and the sliding washer 66 is directed to the end surface of the second bearing portion 26 and the end surface of the second biasing magnet 342. , And can slide around the rotation axis 2. That is, in a state where the washer 51 and the second biasing magnet 342 are biased by the biasing structure 340, the sliding washers 61 and 66 are between the first bearing portion 21 and the washer 51 or the second bearing The same action as in the first embodiment is performed between the portion 26 and the second biasing magnet 342.

  As described above, in the third embodiment, the biasing structure 340 that generates a reaction force on the same magnetic pole surface of the biasing magnets 341 and 342 is used, and the first bearing 21 and the second bearing 26 are used. Axial thrust load is applied. Therefore, between the end face of the first bearing portion 21 and the sliding washer 61, between the sliding washer 61 and the washer 51, between the second biasing magnet 342 and the sliding washer 66, and with the sliding washer 66 Between the end face of the second bearing portion 26 and the holding torque by the static friction force and the holding torque by the loss torque can be obtained. Therefore, also in the third embodiment, the same effect as that of the first embodiment can be obtained.

  Further, in the third embodiment, since the coil spring as in the first and second embodiments is not used, the configuration can be simplified, and the number of manufacturing steps of the motor 1 can be reduced. In addition, by generating a preload in a non-contact manner, the possibility of the generation of noise and the like caused by the coil spring can be reduced.

  [Others]

  You may comprise the inner-rotor type motor which combined the characteristic part of said embodiment suitably. In any case, by using a configuration in which the pressing portion of the armature assembly is pressed toward the first bearing portion by the biasing structure, the rotational position of the motor having a simple configuration can be maintained. it can. For example, as in the second embodiment described above, in a configuration in which the biasing structure does not rotate with the rotation of the rotation shaft, a pair of biasing as in the third embodiment is used as the biasing structure. You may make it use what is comprised using a magnet. Specifically, in the motor having the structure as in the second embodiment, the second biasing magnet is attached to a fixed member attached to the frame assembly, and the first biasing magnet has an axis. It may be displaced in the direction, and may be pressed against the support member by the repulsive force of the biasing magnets. As a result, the commutator can be pressed against the first bearing via the sliding washer to generate a holding torque. Furthermore, the first biasing magnet is prevented from rotating about the rotation axis with respect to the fixed member by utilizing the loose fitting of the polygonal shape as in the second embodiment described above, etc. The holding torque may be generated also with the biasing magnet.

  Other sliding members may be used in place of the sliding washers. In addition, a sliding washer or the like may not be used, and the first bearing portion and the pressing portion of the armature assembly may face each other, or the second bearing portion and the pressing member may face each other.

  In the first and third embodiments described above, the biasing structure is attached to the bracket or plate side so as not to rotate relative to the frame assembly, rather than rotating with the commutator. May be When utilizing the biasing structure using a coil spring, the second embodiment is carried out by pressing a pressing member such as a washer against the end face of the commutator by the coil spring and pressing the pressing portion of the armature assembly against the first bearing portion. The holding torque can be generated in the same manner as in the above. In addition, when using a biasing structure using a pair of biasing magnets, the first biasing magnet, which is disposed so as to be axially displaceable without rotating with respect to the frame assembly, is pressed against the end face of the commutator, By pressing the pressing portion of the armature assembly against the first bearing portion, the holding torque can be generated as in the second embodiment.

  The biasing structure is not limited to one using a coil spring as in the above-described embodiment or one using a biasing magnet. Various configurations can be used to press the rotating shaft towards the first bearing member. For example, the biasing structure may be configured using another type of spring, or may be configured such that the rotation shaft is biased using magnetic attraction.

  The motor is not limited to the above-described brushed inner rotor motor, and may be another type of inner rotor motor such as a brushless inner rotor motor.

  It should be understood that the above embodiments are illustrative and non-restrictive in every respect. The scope of the present invention is indicated not by the above description but by claims, and is intended to include all modifications within the meaning and scope equivalent to claims.

1,201,301 inner rotor type motor 1a, 201a frame assembly 1b, 201b, 301b armature assembly 2 rotary shaft 2a pressing portion 10 frame 21, 221 first bearing portion 26, 226 second bearing portion 30, 330 commutator (Example of support member)
40, 240, 340 Biasing structure 41 Coil spring 51 Washer 56 Washer (an example of pressing member)
61, 66 Sliding washer 230 Commutator (an example of pressing part)
235 support member 250 fixing member 341 first biasing magnet 342 second biasing magnet (an example of pressing member)

  The present invention relates to an inner rotor type motor, and more particularly to an inner rotor type motor capable of holding a rotational position.

  Inner rotor type motors are often used as drive sources in, for example, office equipment and home appliances. Among such inner rotor type motors, there are those used in applications where it is necessary to maintain the rotational position of equipment attached to the rotation shaft of the motor.

  Patent Document 1 below discloses a structure of an inner rotor type electric motor in which braking members on the fixed side and the movable side for performing a braking action are incorporated in a casing so that a stop holding torque can be obtained when power is not supplied. It is done. In this structure, the brake is activated in the non-energized state by the attraction force generated by the position of the magnetic center of the magnet on the casing side and the axial center of the rotor being shifted.

  In Patent Document 2 below, a multi-pole magnetized magnet having a plurality of magnetic poles is provided on one of the rotor side and the stator side on the outer side of the motor frame, and a plurality of magnetized portions and hysteresis are provided on the other to face it. A structure of an apparatus is disclosed in which a braking force and a holding force can be obtained by providing a multipolar magnetized magnet in which both parts are formed.

  Patent Document 3 below discloses, in a valve opening / closing device used for an exhaust gas recirculation device or the like, a structure having a valve-closing return spring in the device.

  Patent Document 4 below discloses the structure of a spindle drive device having a built-in brake device, in which a coil spring for braking is disposed on the axially outer side of the motor.

JP 2001-320856 A Japanese Patent Application Laid-Open 10-150762 JP 2011-211825 A German Patent Application Publication DE 102008061117 A1

  By the way, in a device (set) in which a member is displaced using the inner rotor type motor as described above, when it is necessary to hold the rotational position of the motor corresponding to the position of the member, It is common to provide a retention mechanism near the part that will However, particularly in a set having a configuration in which the motor rotation speed is reduced by the reduction mechanism including gears and the like to displace the members, when the holding mechanism is provided after passing the reduction mechanism from the motor, the holding mechanism is larger Holding power must be exerted. Therefore, in such a case, it is necessary to provide a holding mechanism having a large size and structure, and the set using the inner rotor type motor becomes large or the manufacturing cost becomes high.

  As described in Patent Document 1, when the brake mechanism is provided inside the motor, the holding force of the motor is amplified by the reduction ratio, so the holding mechanism can be simplified. However, the structure described in Patent Document 1 has a problem that the number of parts is large, and a partition plate is provided inside the motor, resulting in an increase in manufacturing cost. Furthermore, since only the magnetic thrust force of the rotor is the force that generates the frictional holding force at the time of deenergization, it is difficult to obtain a high holding force, and a strong magnet should be used to obtain a high holding force. There is an issue at cost disadvantage that it is inevitable.

  The structure as described in Patent Document 2 has a problem that it is difficult to handle because a magnet or the like is provided on the outside of the motor. In addition, it is necessary to configure one of the magnets with uneven thickness, and there is a problem in manufacturing particularly when the size is reduced. Further, by forming the multipolar-magnetized magnet on one side on the rotating side and one on the stationary side, there is a concern of vibration in the thrust direction.

  Patent Document 3 and Patent Document 4 do not disclose effective solutions to the problems described above.

  The present invention has been made to solve such problems, and it is an object of the present invention to provide an inner rotor type motor capable of holding a rotational position with high holding power with a simple and compact configuration.

In order to achieve the above object, according to an aspect of the present invention, a motor includes a rotating shaft , a rotor attached to the rotating shaft, a first bearing portion positioned on one side in the axial direction, and the other side in the axial direction a second bearing section located towards a first bearing portion and a frame for holding the second bearing portion, toward the second bearing portion first bearing portion from an urging structure for urging the rotary shaft The second bearing portion is a metal bearing, and the biasing structure includes a pressing member and a sliding member between the rotor and the second bearing in the axial direction, and the sliding member is a pressing member. The sliding member is slidable with respect to the second bearing portion and the pressing member .

Preferably, the rotation shaft is biased by the restoring force of the spring of the biasing structure or the magnetic attraction force of the biasing structure .

Preferably, the biasing structure comprises a spring, and the sliding member slides relative to the second bearing .

Preferably, the rotating shaft is biased by the magnetic attraction force of the biasing structure, and the sliding member slides relative to the second bearing portion .

Preferably, the rotor comprises a commutator and an armature, the commutator supporting the spring of the biasing structure .

FIG. 1 is a side sectional view showing an inner rotor type motor according to a first embodiment of the present invention. It is a side sectional view showing an inner rotor type motor concerning a 2nd embodiment. It is a side sectional view showing an inner rotor type motor concerning a 3rd embodiment. It is the side view which looked at the commutator concerning a 3rd embodiment from the direction of an axis.

  Hereinafter, an inner rotor type motor according to an embodiment of the present invention will be described.

  First Embodiment

  FIG. 1 is a side sectional view showing an inner rotor type motor 1 according to a first embodiment of the present invention.

  In FIG. 1, the left and right direction may be referred to as an axial direction.

  As shown in FIG. 1, an inner rotor type motor (hereinafter sometimes referred to simply as a motor) 1 roughly includes a frame assembly 1a and an armature set rotatably supported relative to the frame assembly 1a. And 3D (hereinafter, may be simply referred to as an amateur) 1b. The motor 1 is a so-called brushed DC motor.

  The amateur assembly 1 b includes a rotating shaft (shaft) 2, an amateur unit 4, a commutator 30 and the like.

  The amateur part 4 is attached to the rotating shaft 2. The armature unit 4 includes an armature core 5 having a plurality of salient poles projecting in the radial direction, a winding (not shown) wound around each salient pole, and the like.

  The commutator 30 is provided in the vicinity of one end of the rotation shaft 2 (near the bottom). The commutator 30 has a commutator piece (not shown) connected to the winding.

  The frame assembly 1a comprises a frame 10, a bracket 12, a plate 13, a magnet 8 and the like.

  The frame 10 has a cylindrical shape in which one end (a left part in FIG. 1; sometimes referred to as a top) is closed so that the rotation shaft 2 protrudes. The opening of the other end of the frame 10 (the end on the right in FIG. 1; sometimes referred to as the bottom) is closed by the plate 13. The armature 1b is housed inside the frame 10, and the bottom of the frame 10 is constituted by the plate 13, whereby a housing for housing the amateur part 4 inside is constituted. One end of the rotation shaft 2 projects from the top of the frame 10. The power of the motor 2 can be taken out from the protruding portion of the rotating shaft 2.

  A first bearing portion 21 is held at the center of the top of the frame 10. A second bearing portion 26 is held at a central portion of the plate 13. That is, the first bearing portion 21 is located on one side of the armature portion 4 in the axial direction, and the second bearing portion 26 is located on the other side of the armature portion 4 in the axial direction. The rotating shaft 2 is supported by two first bearings 21 and second bearings 26 (sometimes referred to as bearings 21 and 26). The armature 1 b is rotatably held relative to the frame 10 by bearings 21 and 26.

  The bracket unit 20 is configured by the plate 13, the bracket 12, the second bearing portion 26, and a terminal or a brush not shown. That is, the bracket 12 is attached to the inside of the plate 13. The bracket 12 holds a terminal to which an external current is supplied. A brush is connected to the tip of the terminal. The brush is arranged such that the tip contacts the commutator 30 of the armature 1b. Electric power is supplied to the commutator bar on the commutator 30 via the brush, whereby the motor 1 is driven.

  In the present embodiment, the motor 1 has a biasing structure 40 that biases the rotating shaft 2 in one axial direction. The biasing structure 40 is provided between the second bearing portion 26 and the armature portion 4 inside the frame assembly portion 1 a of the motor 1. A pressing portion 2 a having a diameter larger than that of a portion supported by the first bearing portion 21 is provided at a portion of the rotating shaft 2 between the armature portion 4 and the first bearing portion 21. A washer 51 is disposed closer to the first bearing portion 21 than the pressing portion 2a. The washer 51 is rotatable with the rotating shaft 2. The washer 51 may be press-fitted to the rotating shaft 2 or may be loosely fitted to the rotating shaft 2. The biasing structure 40 biases the rotation shaft 2 in a direction away from the second bearing portion 26 (left direction in FIG. 1). As a result, the pressing portion 2 a is pressed together with the washer 51 toward the first bearing portion 21.

  The biasing structure 40 includes a coil spring 41 and a washer (an example of a pressing member) 56. The coil spring 41 is disposed between the second bearing portion 26 and the commutator 30 functioning as a support member when the rotary shaft 2 is biased. The washer 56 is disposed between the coil spring 41 and the second bearing portion 26. The washer 56 is loosely fitted on the rotary shaft 2 and is disposed so as to be axially displaceable.

  The coil spring 41 is disposed such that its coil axis substantially coincides with the axial direction. The coil spring 41 is attached between the commutator 30 and the washer 56 in a compressed state. In the present embodiment, a groove 33 in which a part of the coil spring 41 is embedded in the axial direction is formed on the end face of the commutator 30 on the second bearing 26 side. One axial end of the coil spring 41 is embedded in the groove 33. As described above, since the coil spring 41 is disposed in the groove 33, the space required for arranging the coil spring 41 inside the motor 1 can be saved, and the axial dimension of the motor 1 can be reduced. be able to. Since the coil spring 41 is thus attached to the commutator 30, it rotates together with the rotating shaft 2 and the commutator 30.

  The coil spring 41 tries to extend from the compressed state between the commutator 30 and the washer 56. The restoring force acts to increase the distance between the commutator 30 and the washer 56. That is, the coil spring 41 presses the pressing portion 2 a together with the washer 51 toward the first bearing portion 21 by a restoring force. Also, the coil spring 41 presses the washer 56 toward the second bearing portion 26 by a restoring force.

  A sliding washer 61 is disposed between the first bearing portion 21 and the washer 51. The sliding washer 61 is gently fitted on the rotating shaft 2. The slide washer 61 is rotatable around the rotation shaft 2 with respect to the rotation shaft 2, is rotatable around the rotation shaft 2 with respect to the first bearing portion 21, and is axially displaceable. The washer 51 is pressed against the first bearing 21 via the sliding washer 61. Not only one sliding washer 61 but a plurality of sliding washers 61 may be used.

  A sliding washer 66 is disposed between the second bearing portion 26 and the washer 56. The sliding washer 66 is gently fitted to the rotating shaft 2. The slide washer 66 is rotatable around the rotation shaft 2 with respect to the rotation shaft 2, is rotatable around the rotation shaft 2 with respect to the second bearing portion 26, and is axially displaceable. The washer 56 is pressed against the second bearing portion 26 via the sliding washer 66. Not only one sliding washer 61 but a plurality of sliding washers 61 may be used.

  The bearings 21 and 26 are, for example, metal bearings (oil-impregnated bearings). The end surface of each of the bearings 21 and 26 on the side of the armature portion 4 has a smooth surface perpendicular to the rotation shaft 2. The sliding washer 61 can slide around the rotation shaft 2 with respect to the end face of the first bearing portion 21 and the washer 51 while being sandwiched between the first bearing portion 21 and the washer 51. Similarly, the sliding washer 66 can slide around the rotation shaft 2 with respect to the end face of the second bearing portion 26 and the washer 56 while being sandwiched between the second bearing portion 26 and the washer 56. It is.

  As described above, in the present embodiment, the biasing structure 40 using the coil spring 41 is disposed on the armature 1 b side, and the biasing structure 40 causes the first bearing 21 and the second bearing 26 to move. Axial thrust load is applied. Thus, the holding torque for the rotation of the armature 1b can be obtained by the applied load, the friction coefficient of the surface receiving the thrust load, and the frictional force corresponding to the area of the surface. That is, between the end face of the first bearing 21 and the sliding washer 61, between the sliding washer 61 and the washer 51, between the washer 56 and the sliding washer 66, the sliding washer 66 and the second bearing 26 Between the end face and the end face, holding torque by static friction force and holding torque by loss torque can be obtained. In the state where the rotational torque is not applied, the rotational position of the armature 1b can be held against the external force applied to the rotary shaft 2 under the influence of the holding torque.

  When the motor 1 rotates, the sliding washer 61 slides around the rotation shaft 2 with respect to each of the end face of the first bearing portion 21 and the washer 51. In addition, the sliding washer 66 slides around the rotation shaft 2 with respect to each of the end face of the second bearing portion 26 and the washer 56. Therefore, the motor 1 can rotate smoothly. The members sliding with respect to the sliding washers 61 and 66 may not be all of the bearings 21 and 26 and the washers 51 and 56, and may be appropriately changed according to the rotation condition of the motor 1.

  The holding torque of the motor 1 can be generated with a simple configuration by providing the coil spring 41, the washers 51 and 56, the sliding washers 61 and 66, etc. inside the motor 1. Since the configuration of the motor 1 can be simplified, the manufacturing cost of the motor 1 can be reduced. In many applications where the motor 1 is decelerated using a reduction gear etc., compared to the case where a holding mechanism is provided after decelerating, the same holding force is generated by merely generating a small holding torque on the motor 1 side. be able to. Therefore, the configuration of the system using the motor 1 can be miniaturized or simplified. Further, the reliability of the system using the motor 1 can be enhanced.

  Second Embodiment

  The basic configuration of the motor in the second embodiment is the same as that in the first embodiment, and thus the description thereof will not be repeated. About the member which has a function similar to 1st Embodiment, the same code | symbol as 1st Embodiment may be attached | subjected, and specific description may be abbreviate | omitted. The biasing structure is configured to include a coil spring and a washer as in the first embodiment. The second embodiment is different from the first embodiment in the position at which the biasing structure is provided, the direction in which the biasing structure, and the like are provided. In the second embodiment, the coil spring is provided on the fixed body side, that is, on the frame assembly side.

  FIG. 2 is a side sectional view showing an inner rotor type motor 201 according to a second embodiment.

  In FIG. 2, the left and right direction may be referred to as an axial direction. The motor 201 includes a frame assembly 201a and an armature 201b.

  As shown in FIG. 2, in the frame assembly 201 a, a second bearing portion 226 is held at the center of the top of the frame 10. Conversely, the first bearing portion 221 is held at the central portion of the plate 13. The rotation shaft 2 of the armature 201 b is axially supported by the first bearing portion 221 and the second bearing portion 226.

  Inside the top of the frame 10, a fixing member 250 is fixed. Similar to the groove 33 in the first embodiment described above, the fixing member 250 is formed with a groove 253 in which the coil spring 41 is embedded. The groove portion 253 is formed in an annular shape substantially coaxial with the rotation shaft 2 so as to open toward the first bearing portion 221.

  One axial end of the coil spring 41 is embedded in the groove 253. That is, the coil spring is attached to the frame assembly 201a so as not to rotate with respect to the frame assembly 201a.

  In the second embodiment, the armature 201a has a commutator 230 and a support member 235, which are different in configuration from the first embodiment.

  Unlike the commutator 30 in the first embodiment, the commutator 230 does not have the groove 33 and the coil spring 41 is not embedded. The commutator 230 functions as a pressing portion that is pressed toward the first bearing portion 221 when the rotary shaft 2 is biased as described later. A washer 51 is disposed closer to the first bearing portion 221 than the commutator 230. The washer 51 is rotatable with the rotating shaft 2. The washer 51 may be press-fitted to the rotating shaft 2 or may be loosely fitted to the rotating shaft 2.

  The support member 235 is disposed between the armature portion 4 and the second bearing portion 226. The support member 235 includes a thrust holder 238 protruding from the armature portion 4 to the top side, and a bearing member 236.

  The bearing member 236 is, for example, a sintered oil-impregnated metal. The thrust holder 238 is made of, for example, a resin, and is connected to the armature unit 4. The bearing member 236 is press-fitted to the rotating shaft 2. The thrust holder 238 and the bearing member 236 rotate with the rotating shaft 2. The thrust holder 238 has a wedge shape that opens toward the second bearing portion 226, and a bearing member 236 is disposed therein. Since the outer periphery of the bearing member 236 is covered by the thrust holder 238, scattering of the oil contained in the bearing member 236 by centrifugal force when the armature 201b rotates is prevented.

  In the second embodiment, the biasing structure 240 includes a coil spring 41 attached to the fixing member 250 and a washer (an example of a pressing member) 56. The washer 56 is disposed between the coil spring 41 and the bearing member 236 of the support member 235. The washer 56 is loosely fitted on the rotary shaft 2 and is disposed so as to be axially displaceable. The coil spring 41 is compressed and attached between the support member 235 and the fixing member 250 (that is, between the support member 235 and the second bearing portion 226).

  The biasing structure 240 biases the rotating shaft 2 in a direction away from the second bearing portion 226 (rightward in FIG. 2) by the restoring force of the coil spring 41. That is, the coil spring 41 presses the commutator 230 together with the washer 51 toward the first bearing portion 221. Also, the coil spring 41 presses the washer 56 toward the bearing member 236.

  A sliding washer 61 is disposed between the first bearing portion 221 and the washer 51 as in the first embodiment. That is, the commutator 230 is pressed against the first bearing portion 221 via the sliding washer 66. The sliding washer 61 is slidable around the rotation shaft 2 with respect to the end face of the first bearing portion 221 and the washer 51 in a state of being sandwiched between the first bearing portion 221 and the washer 51. Further, a sliding washer 66 is disposed between the bearing member 236 and the washer 56 as in the first embodiment. The sliding washer 66 is slidable around the rotation axis 2 with respect to the end face of the bearing member 236 and the washer 56 while being sandwiched between the bearing member 236 and the washer 56. That is, in the state where the washers 51 and 56 are respectively biased by the biasing structure 240, the sliding washers 61 and 66 are between the first bearing portion 221 and the washer 51 or between the bearing member 236 and the washer 56. The same functions as in the first embodiment.

  Thus, in the second embodiment, the biasing structure 240 using the coil spring 41 is disposed on the side of the frame assembly 201 a, and the first bearing portion 221 and the bearing member 236 are arranged by the biasing structure 240. And an axial thrust load is applied. Therefore, between the end face of the first bearing portion 221 and the sliding washer 61, between the sliding washer 61 and the washer 51, between the washer 56 and the sliding washer 66, and the end face of the sliding washer 66 and the bearing member 236 Between the above, the holding torque by the static friction force and the holding torque by the loss torque can be obtained. Therefore, also in the second embodiment, the same effect as that of the first embodiment can be obtained.

  In the second embodiment, since the coil spring 41 is disposed on the fixed body side, the commutator 230 can have a simpler configuration.

  Third Embodiment

  The basic configuration of the motor in the third embodiment is the same as that in the first embodiment, and thus the description thereof will not be repeated. About the member which has a function similar to 1st Embodiment, the same code | symbol as 1st Embodiment may be attached | subjected, and specific description may be abbreviate | omitted. The third embodiment is different from the first embodiment in that the biasing structure is configured using a pair of biasing magnets.

  FIG. 3 is a side sectional view showing an inner rotor type motor 301 according to a third embodiment.

  In FIG. 3, the left and right direction may be referred to as an axial direction. As shown in FIG. 3, the motor 301 has a frame assembly 1a and an armature 301b which are configured in the same manner as in the first embodiment. In the motor 301, the structure on the top side (left side in FIG. 3) of the armature unit 4 is the same as that of the first embodiment.

  In the amateur 301 b, a commutator 330 is used instead of the commutator 30. The commutator 330 is fixed to the rotating shaft 2.

  In the third embodiment, the motor 1 has a biasing structure 340 for biasing the rotating shaft 2 in one axial direction. The biasing structure 340 is provided between the second bearing 26 and the armature 4 inside the frame assembly 1 a. Similar to the biasing structure 40 in the first embodiment, the biasing structure 340 biases the rotating shaft 2 in a direction away from the second bearing portion 26 (leftward in FIG. 3). As a result, the pressing portion 2 a is pressed together with the washer 51 toward the first bearing portion 21.

  More specifically, the biasing structure 340 is disposed between the commutator 330 and the second bearing portion 26. The commutator 330 functions as a support member when the biasing structure 340 biases the rotating shaft 2.

  The biasing structure 340 includes a first biasing magnet 341 disposed on the commutator 330 side, and a second biasing magnet 342 disposed on the second bearing portion 26 side of the first biasing magnet 341. There is. Each of the first biasing magnet 341 and the second biasing magnet 342 is a permanent magnet magnetized so as to be divided into two poles in the axial direction.

  The commutator 330 has a protrusion 333 that protrudes in the axial direction from the end face on the second bearing 26 side. The first biasing magnet 341 and the second biasing magnet 342 are disposed in the commutator 330 such that the projecting portion 333 penetrates a hole provided at the central portion. The first biasing magnet 341 and the second biasing magnet 342 are arranged such that the same poles face each other.

  FIG. 4 is a side view of the commutator 330 according to the third embodiment as viewed from the axial direction.

  As shown in FIG. 4, the commutator 330 is formed in a substantially cylindrical shape, and is connected to a cylindrical portion 330 a having a side circumferential surface on which a commutator piece (not shown) is disposed, and to each commutator piece And a commutator riser 330b on which the coil wire is wound. In the third embodiment, the protruding portion 333 protruding from the cylindrical portion 330a has, for example, a polygonal prism shape such as a hexagonal shape. The first biasing magnet 341 and the second biasing magnet 342 conform to the shape of the projecting portion 333 and have a polygonal hole such as, for example, a hexagonal shape sized so as to be gently fitted into the projecting portion 333 There is. Thus, both the first biasing magnet 341 and the second biasing magnet 342 are attached to the commutator 330 so as to be axially displaceable and rotatable with the commutator 330. The first biasing magnet 341 may be press-fit into the projecting portion 333.

  Returning to FIG. 3, the first biasing magnet 341 is supported by the end face of the cylindrical portion 330 a of the commutator 330. Further, a sliding washer 66 is disposed between the second biasing magnet 342 and the end face of the second bearing portion 26.

  Since the first biasing magnet 341 and the second biasing magnet 342 are disposed such that the same poles face each other, a magnetic repulsive force acts between them. The biasing structure 340 presses the pressing portion 2 a and the washer 51 toward the first bearing portion 21 via the sliding washer 61 by the repulsive force. In addition, the biasing structure 340 presses the second biasing magnet 342 itself toward the second bearing via the sliding washer 66 by the repulsive force. The end face on the second bearing 26 side of the second biasing magnet 342 has a smooth surface perpendicular to the axial direction.

  The sliding washer 61 can slide around the rotation shaft 2 with respect to the end face of the first bearing portion 21 and the washer 51 while being sandwiched between the first bearing portion 21 and the washer 51. In addition, the sliding washer 66 is sandwiched between the second bearing portion 26 and the second biasing magnet 342, and the sliding washer 66 is directed to the end surface of the second bearing portion 26 and the end surface of the second biasing magnet 342. , And can slide around the rotation axis 2. That is, in a state where the washer 51 and the second biasing magnet 342 are biased by the biasing structure 340, the sliding washers 61 and 66 are between the first bearing portion 21 and the washer 51 or the second bearing The same action as in the first embodiment is performed between the portion 26 and the second biasing magnet 342.

  As described above, in the third embodiment, the biasing structure 340 that generates a reaction force on the same magnetic pole surface of the biasing magnets 341 and 342 is used, and the first bearing 21 and the second bearing 26 are used. Axial thrust load is applied. Therefore, between the end face of the first bearing portion 21 and the sliding washer 61, between the sliding washer 61 and the washer 51, between the second biasing magnet 342 and the sliding washer 66, and with the sliding washer 66 Between the end face of the second bearing portion 26 and the holding torque by the static friction force and the holding torque by the loss torque can be obtained. Therefore, also in the third embodiment, the same effect as that of the first embodiment can be obtained.

  Further, in the third embodiment, since the coil spring as in the first and second embodiments is not used, the configuration can be simplified, and the number of manufacturing steps of the motor 1 can be reduced. In addition, by generating a preload in a non-contact manner, the possibility of the generation of noise and the like caused by the coil spring can be reduced.

  [Others]

  You may comprise the inner-rotor type motor which combined the characteristic part of said embodiment suitably. In any case, by using a configuration in which the pressing portion of the armature assembly is pressed toward the first bearing portion by the biasing structure, the rotational position of the motor having a simple configuration can be maintained. it can. For example, as in the second embodiment described above, in a configuration in which the biasing structure does not rotate with the rotation of the rotation shaft, a pair of biasing as in the third embodiment is used as the biasing structure. You may make it use what is comprised using a magnet. Specifically, in the motor having the structure as in the second embodiment, the second biasing magnet is attached to a fixed member attached to the frame assembly, and the first biasing magnet has an axis. It may be displaced in the direction, and may be pressed against the support member by the repulsive force of the biasing magnets. As a result, the commutator can be pressed against the first bearing via the sliding washer to generate a holding torque. Furthermore, the first biasing magnet is prevented from rotating about the rotation axis with respect to the fixed member by utilizing the loose fitting of the polygonal shape as in the second embodiment described above, etc. The holding torque may be generated also with the biasing magnet.

  Other sliding members may be used in place of the sliding washers. In addition, a sliding washer or the like may not be used, and the first bearing portion and the pressing portion of the armature assembly may face each other, or the second bearing portion and the pressing member may face each other.

  In the first and third embodiments described above, the biasing structure is attached to the bracket or plate side so as not to rotate relative to the frame assembly, rather than rotating with the commutator. May be When utilizing the biasing structure using a coil spring, the second embodiment is carried out by pressing a pressing member such as a washer against the end face of the commutator by the coil spring and pressing the pressing portion of the armature assembly against the first bearing portion. The holding torque can be generated in the same manner as in the above. In addition, when using a biasing structure using a pair of biasing magnets, the first biasing magnet, which is disposed so as to be axially displaceable without rotating with respect to the frame assembly, is pressed against the end face of the commutator, By pressing the pressing portion of the armature assembly against the first bearing portion, the holding torque can be generated as in the second embodiment.

  The biasing structure is not limited to one using a coil spring as in the above-described embodiment or one using a biasing magnet. Various configurations can be used to press the rotating shaft towards the first bearing member. For example, the biasing structure may be configured using another type of spring, or may be configured such that the rotation shaft is biased using magnetic attraction.

  The motor is not limited to the above-described brushed inner rotor motor, and may be another type of inner rotor motor such as a brushless inner rotor motor.

  It should be understood that the above embodiments are illustrative and non-restrictive in every respect. The scope of the present invention is indicated not by the above description but by claims, and is intended to include all modifications within the meaning and scope equivalent to claims.

1,201,301 inner rotor type motor 1a, 201a frame assembly 1b, 201b, 301b armature assembly 2 rotary shaft 2a pressing portion 10 frame 21, 221 first bearing portion 26, 226 second bearing portion 30, 330 commutator (Example of support member)
40, 240, 340 Biasing structure 41 Coil spring 51 Washer 56 Washer (an example of pressing member)
61, 66 Sliding washer 230 Commutator (an example of pressing part)
235 support member 250 fixing member 341 first biasing magnet 342 second biasing magnet (an example of pressing member)

Claims (13)

An amateur assembly having a rotating shaft and an amateur part,
A first bearing portion located on one side in the axial direction;
A second bearing portion located on the other side in the axial direction;
A frame for holding the first bearing portion and the second bearing portion;
A pressing portion provided on the amateur assembly;
A coil spring for pressing the pressing portion from the second bearing portion toward the first bearing portion;
A sliding washer fitted to the rotary shaft;
The sliding washer is rotatable around the rotation axis and axially displaceable,
A motor, wherein a commutator supporting the coil spring is fixed to a portion of the rotating shaft between the second bearing portion and the armature portion. The coil spring is attached to the commutator so as to rotate with the commutator;
The motor according to claim 1, wherein the coil spring presses a pressing member axially displaceably provided between the coil spring and the second bearing portion against the second bearing portion. A washer disposed between the armature portion and the second bearing portion;
In the axial direction, the sliding washer is between a washer arranged between the armature part and the second bearing part and the second bearing part,
The motor according to claim 1, wherein in the axial direction, the coil spring is between a washer disposed between the armature portion and the second bearing portion and the armature portion. The sliding washer as a first sliding washer, and a second sliding washer; and a washer disposed between the armature portion and the first bearing portion,
The motor according to claim 3, wherein in the axial direction, the second sliding washer is between a washer disposed between the armature portion and the first bearing portion and the first bearing portion.   The motor according to claim 4, wherein a washer disposed between the armature portion and the first bearing portion is rotatable with the rotation shaft.   The motor according to claim 4, wherein the pressing portion is pressed against the first bearing via the second sliding washer.   The motor according to any one of claims 3 to 6, wherein a washer disposed between the armature portion and the second bearing portion is axially displaceable. An amateur assembly having a rotating shaft and an amateur part,
A first bearing portion located on one side in the axial direction;
A second bearing portion located on the other side in the axial direction;
A frame for holding the first bearing portion and the second bearing portion;
A pressing portion provided on the amateur assembly;
And a biasing structure for pressing the pressing portion from the second bearing portion toward the first bearing portion,
In axial direction, the biasing structure comprises opposing first and second permanent magnets,
The same poles of the first permanent magnet and the second permanent magnet face each other,
A support member for supporting the biasing structure is fixed to a portion of the rotation shaft between the second bearing portion and the armature portion.
The first permanent magnet is disposed on the support member so as to rotate with the support member,
The second permanent magnet is disposed on the support member so as to rotate with the support member and axially displaceable, and is pressed against the second bearing portion by the biasing structure. ,motor.   The motor according to claim 8, wherein the support member is a commutator. An amateur assembly having a rotating shaft and an amateur part,
A first bearing portion located on one side in the axial direction;
A second bearing portion located on the other side in the axial direction;
A frame for holding the first bearing portion and the second bearing portion;
A pressing portion provided on the amateur assembly;
And a biasing structure for pressing the pressing portion from the second bearing portion toward the first bearing portion,
In axial direction, the biasing structure comprises opposing first and second permanent magnets,
The same poles of the first permanent magnet and the second permanent magnet face each other,
A motor, wherein a commutator supporting the biasing structure is fixed to a portion of the rotating shaft between the second bearing portion and the armature portion. And a sliding washer fitted to the rotating shaft,
The motor according to any one of claims 8 to 10, wherein the sliding washer is rotatable around the rotation axis and axially displaceable. And a second sliding washer as the first sliding washer.
The motor according to claim 11, wherein the pressing portion is pressed against the first bearing via the second sliding washer. A washer disposed between the armature portion and the first bearing portion;
The motor according to any one of claims 8 to 12, wherein a washer disposed between the armature portion and the first bearing portion is rotatable with the rotation shaft.

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