JP6572087B2 - Electric motor - Google Patents

Description

  The present invention relates to an electric motor including a stator core that is fixed to a housing, a rotor that is rotated with respect to the stator core, and a control board that is housed in the housing and controls a rotation state of the rotor.

  Conventionally, a wheel of a welfare device such as a walking assist device that assists walking motion has been provided with a small, light and flat motor. Thereby, a user's walking motion is assisted by supplying a drive current to an electric motor and driving a wheel. On the other hand, by making the control circuit connected to the motor a closed circuit and causing the motor to function as a power generation brake, the user is prevented from turning forward.

  A flat electric motor that can be used for such welfare equipment is described in Patent Document 1, for example. An electric motor (motor with a speed reduction mechanism) described in Patent Document 1 includes a first housing and a second housing, and a stator (stator core) and a power distribution board (control board) are formed inside the housing formed by abutting them. ) Is housed. The stator is fixed to the first housing, and the power distribution board is fixed to the second housing.

  The stator is formed in an annular shape, and a rotor is rotatably provided at a radially inner side via a predetermined gap. An insulator is attached to the stator, and a coil is wound around the insulator. Furthermore, the end of the coil is electrically connected to a power distribution board (control board).

Japanese Patent Laying-Open No. 2014-081068 (FIG. 1)

  In the electric motor described in Patent Document 1, a coil is disposed between the stator fixed to the first housing and the power distribution board fixed to the second housing so as to straddle both. Normally, the electrical connection between the end of the coil and the power distribution board is performed by soldering or the like. For example, the first housing, the second housing, the power distribution board, etc. may repeatedly contract and expand individually due to temperature differences. When vibration is repeatedly input to the electric motor, cracks may occur in the soldered portion that connects the end of the coil and the power distribution board.

  An object of the present invention is to provide an electric motor that can reliably maintain an electrical connection between a coil and a control board against a temperature difference, vibration, or the like.

An aspect of the present invention is an electric motor including a stator core that is fixed to a housing, a rotor that is rotated with respect to the stator core, and a control board that is housed in the housing and controls a rotation state of the rotor. A terminal mounting portion disposed radially outward of the stator core and an outer peripheral portion disposed radially inward of the terminal mounting portion, an insulator mounted on the stator core, and via the insulator a coil wound around the stator core, and a terminal mounted in front SL terminal mounting portion, provided in the terminal, a first connecting portion which ends of the coil are electrically connected, provided in the terminal is, formed between the second connecting portion in which the control board are electrically connected, the front Symbol outer peripheral portion and the stator core A first gap portion which, that features.

In another aspect of the present invention, between the stator core and the terminal mounting portion, a second gap portion which allows the inclination of the terminal mounting portion.

In another aspect of the present invention, a third gap portion is provided between the terminal mounting portion and the housing to allow the terminal mounting portion to tilt.

  According to the present invention, since a flexible part is formed between the terminal mounting portion and the insulator, even if there is a load such as contraction or expansion of the part due to a temperature difference or vibration, the coil and the control The electrical connection with the substrate can be reliably maintained, and the reliability can be greatly improved.

It is a perspective view which shows the electric motor which concerns on one embodiment of this invention. It is a top view of the electric motor of FIG. It is sectional drawing which follows the AA line of FIG. It is a perspective view which shows the state which isolate | separated the flat motor and the control board. It is a perspective view which shows the connection structure of a flat motor and a control board. FIG. 6 is a plan view of FIG. 5 viewed from above. It is sectional drawing which follows the BB line of FIG.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

  1 is a perspective view showing an electric motor according to an embodiment of the present invention, FIG. 2 is a plan view of the electric motor shown in FIG. 1, FIG. 3 is a cross-sectional view taken along the line AA in FIG. FIG. 5 is a perspective view showing a state in which the flat motor and the control board are separated, FIG. 5 is a perspective view showing a connection structure between the flat motor and the control board, FIG. 6 is a plan view of FIG. These respectively show sectional views along the line BB in FIG.

  An electric motor 10 shown in FIG. 1 is provided in the vicinity of a wheel (not shown) of a walking assist device that is a welfare device. The electric motor 10 operates as a drive source by supplying a drive current from a battery or the like. Thereby, a walk auxiliary device operates and can assist a user's walk operation. In addition, this assist operation | movement is performed by using as a trigger that the walk assistance apparatus was propelled by the user's intention, for example.

  On the other hand, when the control circuit (not shown) of the electric motor 10 forms a closed circuit, the electric motor 10 operates as a generator motor (brake device). As a result, the assist of the walking assistance device is stopped and braking force is generated on the wheels. This braking operation is executed, for example, as a trigger when the walking assist device is pushed against the user's intention, thereby preventing the user from leaning forward.

  As shown in FIGS. 1 to 3, the electric motor 10 is formed in a substantially disk-like flat shape, thereby achieving a reduction in size and weight. The electric motor 10 includes a case 20 and a cover 30 that form an outer shape of the electric motor 10, and the case 20 and the cover 30 are fixed by a plurality of fixing screws SC1 in a state of being in contact with each other. A motor housing chamber MS is formed on the inner side where the case 20 and the cover 30 are abutted. The motor housing chamber MS houses a flat motor 40 that is a brushless motor and a control board 50 that controls the rotation state of the flat motor 40 (rotor 42). Here, the case 20 and the cover 30 constitute a housing in the present invention.

  The cover 30 is formed in a substantially bowl shape by injection molding or the like of a plastic material, and includes a disc-shaped bottom wall portion 31 and a cylindrical side wall portion 32 provided integrally with an outer peripheral portion of the bottom wall portion 31. have. The side wall portion 32 is integrally provided with a first connector fixing portion 32a and a second connector fixing portion 32b. The first and second connector fixing portions 32a and 32b are provided with a cable 33 with a first connector and a second connector. Each cable 34 is fixed. Here, the first and second cables with connectors 33 and 34 are fixed to the first and second connector fixing portions 32a and 32b by connecting members 33a and 34a.

  One side in the longitudinal direction of the cables 33, 34 with the first and second connectors is arranged inside the cover 30 and is electrically connected to the control board 50. On the other hand, the other side in the longitudinal direction of the cables 33 and 34 with the first and second connectors is arranged outside the cover 30 and a battery, an operation switch, a controller, and the like (see FIG. 5) via the female connectors 33c and 34c. An external connector (not shown) connected to a not shown is electrically connected.

  As shown in FIG. 3, the case 20 is formed in a substantially cylindrical shape with a step by casting an aluminum material or the like, and includes a large-diameter wall portion 21 and a small-diameter wall portion 22. The large-diameter wall portion 21 is disposed on the cover 30 side along the axial direction (vertical direction in the drawing) of the case 20, and the small-diameter wall portion 22 is disposed on the side opposite to the cover 30 side along the axial direction of the case 20. .

  A substantially disc-shaped partition wall 23 is integrally provided between the large-diameter wall portion 21 and the small-diameter wall portion 22 along the axial direction of the case 20. The partition wall 23 forms a motor accommodating chamber MS in cooperation with the large-diameter wall portion 21 and the cover 30. In addition, the partition wall 23 forms a reduction gear housing chamber RS in cooperation with the small diameter wall portion 22. That is, the partition wall 23 partitions the motor storage chamber MS and the reduction gear storage chamber RS.

  A through hole 23a through which the rotor shaft 45 passes is provided in the central portion of the partition wall 23, and a first main body 45a of the rotor shaft 45 is rotatably supported inside the through hole 23a in the radial direction. A bearing B1 is mounted.

  A flat motor 40 is accommodated in the motor accommodating chamber MS. The flat motor 40 has an axial dimension smaller than its radial dimension, and thus has a flat shape. The flat motor 40 is an inner rotor type brushless motor, and can be freely rotated via a predetermined gap (air gap) on the inner side in the radial direction of the stator core 41 by laminating a plurality of steel plates. And disposed rotor 42. The stator core 41 is fixed to the large-diameter wall portion 21 of the case 20, whereby the rotor 42 is rotated with respect to the stator core 41.

  An insulator 43 made of an insulating material such as plastic is attached to the stator core 41. The insulator 43 is formed by, for example, injection molding or the like of PBT resin (polybutylene terephthalate). That is, the insulator 43 is made of a flexible material. The insulator 43 covers substantially the entire stator core 41 including a plurality of teeth (not shown), and a coil 44 is wound around the portion of the insulator 43 corresponding to each tooth by concentrated winding. That is, the coil 44 is wound around each tooth of the stator core 41 via the insulator 43.

  The rotor 42 includes a main body 42a formed in a substantially bowl shape by pressing a steel plate. A plurality of permanent magnets 42b are fixed on the outer side in the radial direction of the main body 42a so as to extend along the circumferential direction of the rotor 42. These permanent magnets 42 b are arranged so that N poles and S poles appear alternately along the circumferential direction of the rotor 42. Further, a shaft main body 45a of the rotor shaft 45 is fixed on the radially inner side (rotation center) of the main body portion 42a, and the rotor shaft 45 rotates integrally with the rotor 42.

  The rotor shaft 45 includes a shaft main body 45a, a first shaft portion 45b, and a second shaft portion 45c. The axis of the first shaft portion 45b is a position offset (eccentric) by a predetermined amount from the rotation center of the shaft main body 45a. Is arranged. On the other hand, the axis of the second shaft portion 45c coincides with the rotation center of the shaft body 45a. The shaft body 45a is rotatably supported by the case 20 via the first bearing B1. Therefore, the rotor 42 is rotatably supported on the case 20 by the rotor shaft 45, and the rotor shaft 45 is rotated as the rotor 42 rotates.

  A hypocycloid speed reducer 60 as a speed reduction mechanism is accommodated in the speed reducer accommodation chamber RS. The hypocycloid reducer 60 decelerates the rotation of the flat motor 40 and outputs it to the outside, and includes an outer gear 61 and an inner gear 62.

  The outer gear 61 is formed in an annular shape. The outer gear 61 is disposed closer to the flat motor 40 along the axial direction of the small-diameter wall portion 22, and the outer peripheral portion thereof is fixed to the radially inner side of the small-diameter wall portion 22. On the radially inner side (inner circumference) of the outer gear 61, a tooth portion 61a made of spur teeth is provided.

  The inner gear 62 is provided on the radially inner side of the outer gear 61, and the outer diameter dimension thereof is smaller than the inner diameter dimension of the outer gear 61. On the radially outer side (outer periphery) of the inner gear 62, a tooth portion 62 a made of spur teeth is provided, and the tooth portion 62 a of the inner gear 62 is engaged with the tooth portion 61 a of the outer gear 61. That is, the inner gear 62 rolls without sliding inside the outer gear 61.

  The rotation center of the inner gear 62 is rotatably supported by the first shaft portion 45b of the rotor shaft 45 via a pair of second bearings B2. As a result, the first shaft portion 45b rotates on the radially inner side of the outer gear 61, whereby the inner gear 62 rolls on the radially inner side of the outer gear 61 while rotating around the second bearing B2.

  A plurality of sliding contact holes 62b are provided between the rotation center along the radial direction of the inner gear 62 and the tooth portion 62a so as to be equidistant along the circumferential direction of the inner gear 62. On the radially inner side of these sliding contact holes 62b, an output pin 63a fixed to the output rotating body 63 is slidably contacted by rolling of the inner gear 62 with respect to the outer gear 61.

  On the side opposite to the flat motor 40 side along the axial direction of the hypocycloid reducer 60, an output rotating body 63 is rotatably provided. The output rotating body 63 is formed in a substantially bowl shape, and its radially outer side is rotatably supported by the small diameter wall portion 22 via the third bearing B3. On the other hand, the radially inner side of the output rotating body 63 is rotatably supported by the second shaft portion 45c of the rotor shaft 45 via the fourth bearing B4. Thereby, the backlash to the radial direction of the output rotary body 63 is suppressed.

  A plurality of output pins 63 a are attached to the output rotating body 63 so as to correspond to the sliding contact holes 62 b of the inner gear 62. The plurality of output pins 63a protrude toward the inner gear 62, and the protruding portion extends to the inside of each sliding contact hole 62b. Thereby, each output pin 63a comes into sliding contact with each sliding contact hole 62b.

  Here, the output rotating body 63 is connected to a wheel (not shown) of the walking assistance device so as to be able to transmit power. Thereby, rotation of the flat motor 40 decelerated by the hypocycloid reducer 60 is output to the wheel (external) of the walking assist device. On the contrary, the rotation transmitted from the wheel of the walking assist device to the output rotating body 63 is accelerated by the hypocycloid reducer 60 and transmitted to the flat motor 40.

  Note that the reduction ratio of the hypocycloid reduction gear 60 is, for example, when the number of teeth Z1 of the outer gear 61 is 91 (Z1 = 91) and the number of teeth Z2 of the inner gear 62 is 90 (Z2 = 90). From Z1-Z2) / Z2, the reduction ratio is 1/90. Thus, the hypocycloid reducer 60 can obtain a relatively high reduction ratio in a single stage. Therefore, the electric motor 10 can be employed as a high output type while simplifying the configuration of the speed reduction mechanism and realizing further flattening (thinning) of the electric motor 10.

  A control board 50 is accommodated in the motor accommodating chamber MS. More specifically, the control board 50 is disposed on the cover 30 side along the axial direction of the flat motor 40. The control substrate 50 is obtained by impregnating glass fiber with an epoxy resin and curing it in a plate shape, and is formed in a substantially disk shape and has an insulating property.

  One side in the longitudinal direction of the cables 33 and 34 with the first and second connectors is electrically connected to the first surface 51 opposite to the flat motor 40 side of the control board 50 (not shown in detail). On the other hand, on the second surface 52 of the control board 50 on the flat motor 40 side, as shown in FIG. 3, three Hall sensors HS (only one is shown in the figure) are mounted. These hall sensors HS are opposed to the permanent magnets 42b, and are switched as the rotor 42 rotates. An on / off signal (rectangular wave signal) accompanying the switching operation of the hall sensor HS is sent to an external controller (not shown) via the first and second cables with connectors 33 and 34. Thereby, the controller can grasp the rotation state of the rotor 42. Thus, the control board 50 controls the rotation state of the rotor 42 in cooperation with the external controller.

  As shown in FIG. 4, a plurality of through holes TH are provided in the outer peripheral portion of the control board 50. These through holes TH penetrate the first surface 51 side and the second surface 52 side, and each through hole TH is electrically connected to a wiring (not shown) printed on the control board 50. Conductive conductive film 53 (see FIGS. 5 and 7) is formed. Then, the second connection portion 73 (see FIG. 5) of the terminal 70 attached to the terminal attachment portion 43a of the insulator 43 is inserted into each through hole TH and soldered under the state.

  As shown in FIGS. 5 to 7, a plurality of terminal mounting portions 43 a are integrally provided on the radially outer side of the insulator 43. These terminal mounting portions 43 a are provided so as to partially protrude outward in the radial direction from the stator core 41. That is, the terminal mounting portion 43 a is disposed on the outer side in the radial direction than the stator core 41. As shown in FIG. 5, these terminal mounting portions 43a are formed in a substantially rectangular parallelepiped shape extending along the circumferential direction of the insulator 43, and each terminal mounting portion 43a has a mounting groove 43b extending in the longitudinal direction thereof. Is formed. A terminal 70 that is a conductive member is mounted in the mounting groove 43b by a fixing means such as press fitting.

  As shown in FIG. 5, the terminal 70 includes a terminal body 71 that is formed in a substantially U shape by pressing a brass plate excellent in conductivity and fixed to the mounting groove 43 b. A first connection portion 72 to which the end portion 44 a of the coil 44 is electrically connected is integrally provided on one side in the longitudinal direction of the terminal body 71. In addition, a second connection portion 73 to which the conductive film 53 of the control board 50 is electrically connected is integrally provided on the other side in the longitudinal direction of the terminal body 71.

  And the protrusion height from the terminal main body 71 of the 1st connection part 72 is lower than the protrusion height from the terminal main body 71 of the 2nd connection part 73. As shown in FIG. Thus, the first connection portion 72 does not come into contact with the control board 50 under the state where the second connection portion 73 is electrically connected to the control board 50. Here, the end portion 44a of the coil 44 and the first connection portion 72, and the conductive film 53 and the second connection portion 73 of the control board 50 are connected by soldering using a soldering iron T, respectively. As shown in FIGS. 4 and 5, the control board 50 is fixed to the case 20 by a plurality of fixing screws SC <b> 2 while maintaining a predetermined distance from the flat motor 40.

  As shown in FIG. 6, the radial dimension R2 of the portion where the coil 44 and the control board 50 are electrically connected, that is, the portion where the terminal 70 is disposed, is larger than the radial dimension R1 of the stator core 41. (R1 <R2). That is, as shown in FIG. 8, the electrical connection between the coil 44 and the control board 50 is performed outside the stator core 41 in the radial direction.

  As shown in FIG. 7, a first gap CL <b> 1 having a dimension S <b> 1 along the axial direction of the stator core 41 is formed between the outer peripheral portion 43 c provided in the insulator 43 and the stator core 41. As a result, the outer peripheral portion 43c of the insulator 43 having flexibility (flexibility) can be tilted (oscillated) around the base bending center CE1 as indicated by a two-dot chain line and a broken line arrow M in the figure. It has become.

  Here, the outer peripheral part 43c is provided between the insulator 43 and the terminal mounting part 43a, and comprises the site | part which has the flexibility in this invention.

  Between the terminal mounting part 43a provided integrally with the outer peripheral part 43c of the insulator 43 and the stator core 41, a second gap CL2 having a dimension S2 along the radial direction of the stator core 41 is formed. The gap dimension S2 of the second gap CL2 is smaller than the gap dimension S1 of the first gap CL1 (CL2 <CL1). Further, a third gap CL <b> 3 having a dimension S <b> 3 along the axial direction of the stator core 41 is formed between the terminal mounting portion 43 a and the case 20. The gap dimension S3 of the third gap CL3 is substantially the same as the gap dimension S2 of the second gap CL2 (CL3≈CL2). As a result, the terminal mounting portion 43a provided integrally with the outer peripheral portion 43c having flexibility (flexibility) is inclined (swinged) about the bending center CE2 as indicated by a two-dot chain line and a broken line arrow M in the figure. Is possible).

  Here, the second gap CL2 constitutes a first allowable tilt gap in the present invention, and the third clearance CL3 constitutes a second allowable tilt gap in the present invention. In other words, the second gap CL2 and the third gap CL3 each allow the terminal mounting portion 43a to be inclined.

  The outer peripheral portion 43c and the terminal mounting portion 43a of the insulator 43 are integrally formed by injection molding or the like of a flexible material such as PBT resin, but at least only the outer peripheral portion 43c is flexible. You may have. Specifically, for example, only the outer peripheral portion 43c may be formed of PBT resin or the like by two-color molding, and the other portion of the insulator 43 may be formed of resin or the like harder than the PBT resin.

  Here, in FIGS. 4, 5, and 7, hatching is applied to make it easy to understand the arrangement relationship of the conductive members that conduct electricity.

  As described above in detail, according to the electric motor 10 according to the present embodiment, the outer peripheral portion 43c having flexibility is formed between the terminal mounting portion 43a and the insulator 43. Even if there is a load such as expansion or vibration, the electrical connection between the coil 44 and the control board 50 can be reliably maintained, and the reliability can be greatly improved.

  Moreover, according to the electric motor 10 according to the present embodiment, since the whole insulator 43 is formed by injection molding or the like of a flexible material such as PBT resin, the whole insulator 43 is given flexibility. be able to. Therefore, it is possible to more reliably prevent cracks and the like from occurring in the solder part (see FIG. 8).

  Furthermore, according to the electric motor 10 according to the present embodiment, since the first gap CL1 whose dimension along the axial direction of the stator core 41 is S1 is formed between the outer peripheral portion 43c of the insulator 43 and the stator core 41, the terminal The mounting portion 43a can be inclined more easily. Therefore, reliability can be further improved.

  In addition, according to the electric motor 10 according to the present embodiment, the second gap CL2 whose dimension along the radial direction of the stator core 41 is S2 is formed between the terminal mounting portion 43a and the stator core 41, and the terminal mounting portion 43a. A third gap CL3 having a dimension along the axial direction of the stator core 41 of S3 is formed between the case 20 and the case 20. Therefore, when the terminal mounting portion 43a is inclined, the terminal mounting portion 43a can be prevented from contacting the stator core 41 and the case 20. Therefore, an excessive load is applied to the terminal mounting portion 43a, and the terminal mounting portion 43a can be prevented from being damaged early.

  It goes without saying that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. In the above embodiment, in order to suppress the thickness dimension of the flat motor 40 as much as possible, the terminal mounting portion 43a is disposed on the radially outer side from the stator core 41. However, the present invention is not limited to this, and the thickness of the flat motor 40 is not limited thereto. If the dimensions can be made thicker than in the present embodiment, the terminal mounting portion 43a may be disposed above the stator core 41.

  Moreover, in the said embodiment, although the case where the electric motor 10 was applied to the vicinity of the wheel of the walking assistance apparatus which is welfare equipment was shown, this invention is not limited to this, It applies to the vicinity of axles, such as a wheelchair apparatus. The present invention can also be applied to devices for other uses.

10 Electric motor 20 Case (housing)
21 Large-diameter wall portion 22 Small-diameter wall portion 23 Partition wall 23a Through-hole 30 Cover (housing)
31 Bottom wall portion 32 Side wall portion 32a First connector fixing portion 32b Second connector fixing portion 33 Cable with first connector 33a Connection member 33c Female connector 34 Cable with second connector 34a Connection member 34c Female connector 40 Flat motor 41 Stator core 42 rotor 42a main body 42b permanent magnet 43 insulator 43a terminal mounting part 43b mounting groove 43c outer peripheral part (part having flexibility)
44 coil 44a end 45 rotor shaft 45a shaft body 45b first shaft portion 45c second shaft portion 50 control board 51 first surface 52 second surface 53 conductive film 60 hypocycloid reducer 61 outer gear 61a tooth portion 62 inner gear 62a Tooth part 62b Sliding contact hole 63 Output rotating body 63a Output pin 70 Terminal 71 Terminal body 72 First connection part 73 Second connection part B1 First bearing B2 Second bearing B3 Third bearing B4 Fourth bearing CE1, CE2 Deflection center CL1 1st clearance CL2 2nd clearance (1st inclination permissible clearance)
CL3 3rd clearance (2nd permissible clearance)
HS Hall sensor MS Motor chamber RS Reducer chamber SC1, SC2 Fixing screw TH Through hole

Claims (3)

A stator core fixed to the housing;
A rotor rotated relative to the stator core;
A control board housed in the housing and controlling the rotational state of the rotor;
An electric motor with
A terminal mounting portion disposed radially outside the stator core and a flexible outer peripheral portion disposed radially inner than the terminal mounting portion; an insulator mounted on the stator core;
A coil wound around the stator core via the insulator ;
And a terminal to be mounted before Symbol terminal mounting portion,
A first connection portion provided in the terminal and electrically connected to an end of the coil;
A second connection portion provided in the terminal and electrically connected to the control board ;
A first gap portion formed between the before and Symbol outer periphery the stator core,
That has an electric motor. The electric motor according to claim 1,
Between the terminal mounting portion and the stator core, a second gap portion that allows the terminal mounting portion to be inclined is provided.
Electric motor. The electric motor according to claim 1 or 2 ,
Between the terminal mounting portion and the housing, a third gap portion that allows the terminal mounting portion to be inclined is provided.
Electric motor.

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