JP5195458B2 - Electric motor and electric power steering apparatus provided with the electric motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric motor in which the improvement of its reliability and low cost can be achieved by surely closing a wiring opening drilled in a flange member which closes an opening of a motor casing, and to provide an electric power steering device equipped with the motor. <P>SOLUTION: The electric motor includes: a motor shaft supported rotatably inside the motor casing; a motor rotor provided peripherally on the motor shaft inside the motor casing; a motor stator of plural phases provided peripherally on the inside circumferential surface inside the motor casing; a terminal block, which connects the motor stator of each phase to power supply members for each motor stator at the opening surface side of the motor casing; and a motor rotor position detection means provided on the outer surface of the flange member. In this electric motor, an insulation member provided on the position detection means is structured to close the wiring opening drilled in the flange member for connecting the power supply members to the terminal block from outside a box. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to an electric motor and an electric power steering apparatus using the electric motor as a generation source of steering assist torque.

  In a general electric motor, a front bearing and a motor case disposed in a flange member covering an opening of the motor case in a bottomed cylindrical motor case in which a motor stator is attached along an inner peripheral surface. A motor rotor and a motor shaft integrally coupled with the motor rotor are rotatably supported via a rear bearing disposed at the center of the bottom surface. In the motor case, the terminal block for connecting each phase coil and the terminal of the power supply member (power harness, bus bar, etc.) connected to the controller are electrically connected by welding, screw fastening, fusing (resistance welding), etc. Connected (see Patent Document 1).

  In this type of electric motor, a connection opening is formed in a part of the outer surface of a flange member cast from aluminum or the like so that the terminal block and the power supply member can be connected from the outside. Since this connection opening communicates with each phase coil, if foreign matter enters from there, there is a possibility that the electromagnetic brake state will be entered and locked. Therefore, in a conventional electric motor, a closing member such as a cover or a cap made of an insulating member such as a resin is attached to the opening for connection, thereby preventing foreign matter from entering.

JP 2004-157056 A

  However, the closing member of the conventional electric motor as described above is generally formed in a shape having an insertion function in order to reduce the number of parts, and is generally fitted and fixed to the connection opening. For this reason, the closing member may be damaged or dropped due to the influence of vibration or heat generated in the installation environment of the electric motor. In particular, in the case of an electric motor applied as a drive source for an electric power steering device (EPS), the flange surface of the electric motor is attached to a part of a gear housing that houses a worm reducer or the like. Since this gear housing is a part that generates relatively large vibrations in the electric power steering device, there is a high possibility that the closing member will drop off from the opening for connection, and noise generated by the dropped member is likely to occur. There was concern.

  In addition, in the electric motor for EPS, when the closing member is dropped as described above, due to the mounting structure to the gear housing, the dropped closing member enters the gear housing and interferes with the worm reducer or the bearing. However, in the worst case, there is a possibility that the steering lock state is set.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to reliably connect a connection opening formed in a flange member that closes an opening of a motor case without increasing the number of parts. An object of the present invention is to provide an electric motor capable of improving reliability at a low cost by closing the cover, and an electric power steering device including the electric motor.

  In the above object of the present invention, an external housing is constituted by a bottomed cylindrical motor case having an open end and a flange member attached to the motor case so as to close the opening. In the electric motor, a motor shaft rotatably supported in the motor case, a motor rotor provided around the motor shaft in the motor case, and an inner surface of the motor case so as to surround an outer peripheral surface of the motor rotor. A plurality of phases of motor stators provided around a peripheral surface; a terminal block for connecting the motor stators and power supply members for the motor stators on the opening surface side of the motor case; and an outer surface of the flange member A position detection means for the motor rotor provided on the power supply member, and the flange member from the outside of the outer casing. When the position detecting means is attached to the outer surface of the flange member, the connection opening is provided in the position detecting means. This is achieved by being blocked by the formed insulating member.

  Further, the above object is a resolver in which the position detecting means includes a resolver rotor provided around a part of the motor shaft, and a resolver stator arranged so as to surround an outer peripheral surface of the resolver rotor, And it is achieved effectively because the insulating member is an insulator which insulates the core and coil of the resolver stator.

  Further, the above object is a resolver in which the position detecting means includes a resolver rotor provided around a part of the motor shaft, and a resolver stator arranged so as to surround an outer peripheral surface of the resolver rotor, In addition, the insulating member is effectively a cover portion that partially covers the coil of the resolver stator.

  Moreover, the said objective is effectively achieved by the shape extended | stretched from the said resolver stator to the outer-diameter direction so that the said insulating member may become the same phase as the derivation | leading-out direction of the sensor harness of the said resolver.

  Moreover, the said objective is effectively achieved by the shape extended | stretched in the outer-diameter direction from the said resolver stator so that the said insulating member may become another phase with the lead-out direction of the sensor harness of the said resolver.

  Further, the above object is effectively achieved by the sensor harness of the position detecting means being led out through the spigot projection provided on the outer surface of the flange member in the outer diameter direction. .

  Further, the above object is achieved by an electric power steering apparatus provided with the above electric motor as a generation source of the steering assist force applied to the steering mechanism.

  Further, the above object is that the electric power steering device decelerates the rotational force of the electric motor and transmits the decelerating mechanism to the steering mechanism, and the motor mounting in which the electric motor is fixed. This is achieved effectively by having a gearbox with a surface.

  According to the electric motor and the electric power steering apparatus including the electric motor according to the present invention, a part of the flange member that closes the opening surface of the motor case in order to connect the terminal block and the power feeding member from the outside of the housing. The connection opening is perforated, and the connection opening is closed by the insulating member of the position detecting means attached to the outer surface of the flange member. That is, the insulating member of the position detecting means, which is a component of the existing electric motor, is attached to the outer surface of the flange member so as to function as a closing member for the connection opening. As a result, there is no need to provide a separate member such as a cover or cap for closing the connection opening as in the prior art, and the connection opening can be reliably closed without increasing the number of components. As a result, the number of parts and assembly man-hours of the electric motor are reduced, so that the manufacturing cost can be reduced.

  Further, in the electric motor according to the present invention and the electric power steering apparatus provided with the electric motor, one component of the position detecting means in which the connection opening has a relatively high durability against heat and vibration. Due to the structure that is closed by, concerns such as breakage and dropout are reduced, and reliability can be improved.

It is a front view showing the appearance of the electric motor concerning a 1st embodiment of the present invention. It is sectional drawing of the electric motor along the II-II line | wire in FIG. It is a principal part enlarged view of the electric motor shown in FIG. It is a perspective view which shows the external appearance of the resolver stator attached to an electric motor. It is a front view of the electric motor which shows the state which removed the resolver stator. It is a mechanism figure showing a schematic structure of an electric power steering device provided with an electric motor concerning an embodiment of the present invention. It is principal part sectional drawing which shows the state with which the electric motor which concerns on 1st Embodiment was attached to the gear box of the electric power steering apparatus. It is a front view which shows the external appearance of the electric motor which concerns on 2nd Embodiment of this invention. It is a front view which shows the external appearance of the electric motor which concerns on 3rd Embodiment of this invention. It is sectional drawing of the electric motor along the XX line in FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a front view showing an appearance of the electric motor according to the first embodiment of the present invention. 2 is a cross-sectional view of the electric motor taken along line II-II in FIG. 1, and FIG. 3 is an enlarged view of a main part of the electric motor shown in FIG.

  In these drawings, the external housing of the electric motor 1 according to the present embodiment includes a motor case 2 that is formed in a substantially hollow cylindrical shape, and an opening on one end side (left side in FIG. 2) of the motor case 2 closed. The motor case 2 and the flange member 3 are coupled to each other by screw fastening, press-fitting, adhesion, or the like. Bearings 4 and 5 are press-fitted and fixed to the bottom center recess 2a of the motor case 2 and the inner center recess 3a of the flange member 3 (in the case of the outer ring holding structure of the bearing housing, the inner diameter is set as a clearance). The motor shaft 6 is rotatably supported via 4 and 5. A motor rotor 7 is provided around the motor shaft 6 in the motor case 2 so as to rotate integrally with the motor shaft 6. On the other hand, on the inner peripheral surface of the motor case 2 facing the motor rotor 7, a motor is provided. The stator 8 is provided so as to surround the outer peripheral surface of the rotor motor 7.

  The motor rotor 7 is composed of a rotor core that is press-fitted into the motor shaft 6 or formed integrally with the motor shaft 6. A plurality of magnets are arranged at equal intervals on the outer peripheral surface of the rotor core (in the rotor core in the case of an embedded magnet type) via an adhesive or a holding member. Cover (nonmagnetic SUS material, aluminum, heat shrinkable tube, etc.) is provided.

  The motor stator 8 is composed of a stator core 8a constituted by any one of an integral, divided and sintered core, an insulator 8b inserted into the stator core 8a, and a motor coil 8c wound around the insulator 8b. Yes. Since the electric motor 1 according to the present embodiment is a three-phase motor, the number of stator cores 8a of the motor stator 8 is 3n (a multiple of 3), and the 3n stator cores 8a are respectively connected to the yoke portions. Each (back yoke) is integrated by being press-fitted or welded, and is fixed inside the motor case 2 by press-fitting, adhesion, shrink fitting or the like. In addition, the structure which integrates the stator core 8a is not limited to this, For example, what connected the stator core 8a or what integrated by welding the connection part may be used. Here, the description has been given on the assumption that each stator core 8a is integrated in order to improve workability. However, the present invention is not limited to this, and there is a particular problem even if each stator core 8a is not integrated. There is no.

  A terminal block 9 electrically connected to each phase motor coil 8c is disposed at one end side (left side in FIG. 2) of the motor stator 8 having such a configuration. The stator 8 and the current supply power harness 10 are connected to each other. When performing this connection, first, the motor case 2 and the flange member 3 are coupled with each power harness 10 being sandwiched, and then the surface of the flange member 3 at the same position as the terminal block 9 is drilled. Each power harness 10 and the terminal block 9 are electrically connected by applying a connection means through the connection opening 3b. That is, the operation of connecting each power harness 10 and the terminal block 9 is performed from the outside of the flange member 3 coupled to the motor case 2 through the connection opening 3b. (Tungsten Inert Gas) Welding or screw fastening is performed.

  A rotor (hereinafter referred to as a resolver rotor) 12 of a resolver 11 for detecting a rotation angle (rotation position) of the motor rotor 7 is fixed to one end side (left side in FIG. 2) of the motor shaft 6 positioned outside the flange member 3 by press fitting or the like. Thus, the motor shaft 6 and the motor rotor 7 rotate together. On the other hand, a stator (hereinafter referred to as a resolver stator) 13 of a substantially hollow cylindrical resolver 11 is fixed to the outer central recess 3c formed on the outer surface of the flange member 3 by fastening with a screw 14 or caulking or the like. It is arranged so as to surround the outer peripheral surface.

  FIG. 4 is a perspective view showing an appearance of a resolver stator attached to the electric motor, and FIG. 5 is a front view of the electric motor showing a state in which the resolver stator is removed.

  As shown in FIG. 4, the resolver stator 13 includes a core part 13a having an outer peripheral part and a plurality of teeth formed by pressing and laminating thin electromagnetic steel sheets, and an integral mold or fitting to the core part 13a. An insulator 13b made of an insulative material (resin or the like) mounted together, a sensor coil 13c wound around each tooth of the core portion 13a through a part of the insulator 13b, and a sensor coil 13c in the insulator 13b A sensor harness 13d to which each terminal is connected (welded) and an insulating sensor cover 13e that partially covers the sensor coil 13c wound around the teeth of the core portion 13a are provided.

  The sensor harness 13d is composed of an excitation winding and a detection winding, and an induced voltage is generated in the detection winding when an excitation voltage is applied to the excitation winding. When the resolver rotor 12 rotates in this state, the gap permeance between the resolver rotor 12 and the resolver stator 13 changes according to the rotation angle, and accordingly, the amplitude of the induced voltage generated in the detection winding is modulated. The resolver 11 detects the rotation angle of the motor rotor 7 based on the amplitude modulation of the induced voltage. Further, a notch 3d ′ for leading out the sensor harness 13d is formed in a part of the spigot protrusion 3d provided around the outer surface of the flange member 3, and the sensor harness is previously provided in the notch 3d ′. A sensor grommet 15 inserted into 13d is fitted. That is, the sensor harness 13d passes through the spigot protrusion 3d via the sensor grommet 15 and is led out to the outside to have a wiring structure.

  The insulator 13b has a protruding portion formed so as to protrude from the outer periphery of the core portion 13a along the direction in which the power harness 10 and the sensor harness 13d are led out. The protruding portion is formed on the outer side of the flange member 3 by the resolver stator 13. When attached to the surface, the connection opening 3b is closed. A recess 13b ′ is provided at a portion of the insulator 13b facing the connection opening 3b so as not to contact the terminal block 9 protruding from the outer surface of the flange member 3 and the connection terminals 9a and 10a of the power harness 10. Is formed.

  At the substantially central portion in the stacking direction of the resolver stator 13, the flange portions 13f and 13f are formed integrally with the insulator 13b so as to protrude from the outer periphery in the outer diameter direction. A long hole 14 a for the screw 14 is formed in the flange portion 13 f along the outer peripheral direction of the resolver stator 13. The screw 14 inserted through the long hole 14 a is screwed into a screw hole 14 b formed on the outer surface of the flange member 3, whereby the resolver stator 13 is fixed to the flange member 14. The fixing by screw fastening is performed after the motor shaft 6 is rotated from the outside and the induced voltage and the resolver signal are adjusted.

  FIG. 6 is a mechanism diagram illustrating a schematic configuration of an electric power steering apparatus including the electric motor according to the embodiment of the present invention. In the figure, the steering mechanism of the electric power steering apparatus 20 includes a steering shaft 22 that rotates in response to a steering operation of a steering wheel 21 attached to the tip portion, and a universal joint 23 on the other end side of the steering shaft 22. 24, a rack and pinion mechanism 25 that converts the rotational motion of the steering shaft 22 into a linear motion of the rack shaft, and a tie rod 26 that transmits the motion of the rack shaft of the rack and pinion mechanism 25 to the steering wheel. It is composed of

  Further, a torque sensor 27 that detects a steering torque input to the steering shaft 22 via the steering wheel 21 and a steering coupled to the steering shaft 22 via the speed reduction mechanism 28 are provided in the column portion of the electric power steering apparatus 20. An auxiliary electric motor 1 is provided, and the driving of the electric motor 1 is controlled by a control unit (ECU) 29 equipped with a control circuit and the like. The control unit 29 is supplied with electric power from a battery (power source) 30 and is also detected by an ignition key signal IG from the ignition key 31, a steering torque value signal T detected by the torque sensor 27, and a vehicle speed sensor 32. A vehicle speed signal V is input. The control unit 29 is activated in response to the input of the ignition key signal IG, calculates the steering assist command value I based on the steering torque value T and the vehicle speed V, and the electric motor according to the calculated steering assist command value I The drive current supplied to 1 is controlled.

  The electric power steering device 20 described above is a column assist type in which the electric motor 1 is disposed in the column portion, but is not limited to this, for example, the electric motor 1 is disposed in the pinion portion of the rack and pinion mechanism. It may be a pinion assist type, or a rack assist type in which the electric motor 1 is disposed in the rack portion.

  FIG. 7 is a main part sectional view showing a state in which the electric motor according to the first embodiment is attached to the gear box of the electric power steering apparatus. In the figure, the electric motor 1 described above has a flange in a state where the outer surface of the flange member 3 is in contact with the motor mounting surface of the gear box 35 in which the worm 33 and the worm wheel 34 constituting the speed reduction mechanism 28 are accommodated. A bolt 36 inserted through the bolt hole 3e of the member 3 is fixed by being fastened to a screw hole 35a formed on the motor mounting surface, and the spigot protrusion 3d provided around the outer surface of the flange member 3 is It is fitted in an inlay recess (hollow opening) 35b formed in the motor mounting surface 35a in a shape corresponding to the inlay protrusion 3d.

  The worm 33 is rotatably supported via bearings 36 and 37 disposed at both ends, and a worm wheel 34 that meshes with the worm 33 is an output shaft (not shown) of the steering shaft 22 in the gear box 35. ). The motor shaft 6 and the worm 33 are engaged with a spline shaft portion 6a formed at the distal end portion of the motor shaft 6 in a spline hole 33a formed at the base end portion (right side in FIG. 7) of the worm 33. Transmission of rotational force by the electric motor 1 is freely coupled. In this case, the coupling between the motor shaft 6 and the worm 33 is a spline coupling, but the present invention is not limited to this. For example, a coupling by an elastic coupling or the like may be used.

  As described above, according to the electric motor 1 according to the present embodiment and the electric power steering apparatus 20 including the electric motor 1, the insulator 13 b that is one component of the resolver 11 attached to the outer surface of the flange member 3. A part of the flange member 3 is formed so as to protrude in the outer diameter direction, and the protruding portion of the protruding insulator 13b is connected to connect the terminal block 9 and the power harness 10 with each other. Is to be blocked. As a result, the connection opening 3b can be reliably closed without increasing the number of parts, and the number of parts and the number of assembly steps can be reduced to reduce the manufacturing cost.

  The insulator 13b for closing the connection opening 3b is made of an insulating material having a relatively high durability against heat and vibration, and is fastened together with the resolver stator 13 to the outer surface of the flange member 3 by screws 14. Since it is firmly fixed by crimping or caulking, the concern about breakage or dropout caused by the conventional closing structure in which another member such as a cap or cover is inserted into the connection opening 3b is reduced, and reliability is improved. Can be planned.

  Furthermore, in the electric motor 1 according to the present embodiment, the drawing directions of the power harness 10 and the sensor harness 13d are in the same phase, so that the harnesses can be easily bundled and the electric power steering device. Since the wiring of the harness in the vehicle on which the vehicle 20 is mounted is also facilitated, the mountability can be improved.

  In the electric motor 1 according to the first embodiment described above, the connection opening 3b of the flange member 3 is closed by the protruding portion of the insulator 13b. However, the present invention is not limited to this. For example, the resolver A part of the insulating sensor cover 13e that partially covers the sensor coil 13c of the stator 13 is formed so as to protrude in the outer diameter direction in the same manner as the protruding portion of the insulator 13b, and the flange is formed by the protruding portion of the sensor cover 13e. The structure which closes the opening part 3b for connection of the member 3 may be sufficient.

  FIG. 8 is a front view showing the appearance of the electric motor according to the second embodiment of the present invention. In the figure, the same members as those in the first embodiment described above are denoted by the same reference numerals, and the description thereof is omitted.

  As illustrated in FIG. 8, the pull-out direction of the sensor harness 13Ad of the resolver 11A may be in a different phase from the pull-out direction of the power harness 10 due to the installation layout of the electric motor 1A. Therefore, in the electric motor 1A according to the present embodiment, the insulator 13Ab of the resolver 11A includes the protruding portion 13Ab (1) protruding from the outer peripheral portion of the core along the pulling direction of the sensor harness 13Ad, and the power harness 10 from the outer peripheral portion of the core. When the resolver stator 13A is attached to the outer surface of the flange member 3, the connection opening 3b is blocked by the protrusion 13Ab (2). The protrusion 13Ab (2) extends along the pull-out direction. It has become so.

  According to the electric motor 1A according to the present embodiment having the above-described configuration and the electric power steering apparatus provided with the electric motor 1A, the sensor can be used in addition to the same operational effects as the first embodiment described above. Even when the phases of the harness 13Ad and the power harness 10 in the pull-out direction are different, the connection opening 3b of the flange member 3 can be reliably closed by the protrusion 13Ab (2) of the insulator 13Ab.

  FIG. 9 is a front view showing the appearance of the electric motor according to the third embodiment of the present invention, and FIG. 10 is a cross-sectional view of the electric motor along the line XX in FIG. In these drawings, the same members as those in the first embodiment described above are denoted by the same reference numerals, and the description thereof is omitted.

  As shown in FIGS. 9 and 10, in the electric motor 1 </ b> B according to the present embodiment, the first embodiment described above in that the power feeding member for each motor stator 8 connected to the terminal block 9 is the bus bar terminal 10 </ b> B. It is different from the form. Each bus bar terminal 10 </ b> B is sandwiched between the motor case 2 and the flange member 3 in a state of being inserted in the bus bar grommet 16 in advance, and then the flange member 3 formed at a position corresponding to each terminal of the terminal block 9. The connection opening 3b is electrically connected to each terminal of the terminal block 9 by performing TIG welding, screw fastening, or the like.

  According to the electric motor 1B according to the present embodiment having the above-described configuration and the electric power steering apparatus including the electric motor 1B, the same operational effects as those of the first embodiment described above can be obtained. The present invention can also be applied to a case where the power supply member for the motor stator 8 is the bus bar terminal 10B.

  As mentioned above, although embodiment of this invention was described concretely, this invention is not limited to this, In the range which does not deviate from the meaning, it can change suitably.

DESCRIPTION OF SYMBOLS 1, 1A, 1B ... Electric motor 2 ... Motor case 3 ... Flange member 3b ... Connection opening 3d ... Inlay protrusion 4, 5 ... Bearing 6 ... Motor Shaft 7 ... Motor rotor (rotor core)
8 ... Motor stator 9 ... Terminal block 10 ... Power harness (power supply member)
10B: Busbar terminal (power supply member)
11, 11A... Resolver (position detection means)
DESCRIPTION OF SYMBOLS 12 ... Resolver rotor 13, 13A ... Resolver stator 13a ... Core part 13b, 13Ab ... Insulator (insulating member)
13c ... sensor coils 13d, 13Ad ... sensor harness 13e ... sensor cover 20 ... electric power steering device 28 ... deceleration mechanism 33 ... worm 34 ... worm wheel 35 ... gear box

Claims (8)

An electric motor in which an external housing is constituted by a bottomed cylindrical motor case having an open end and a flange member attached to the motor case so as to close the opening,
A motor shaft rotatably supported in the motor case;
A motor rotor provided around the motor shaft in the motor case;
A multi-phase motor stator that is provided around the inner peripheral surface of the motor case so as to surround the outer peripheral surface of the motor rotor;
A terminal block for connecting each motor stator and a power supply member for each motor stator on the opening surface side of the motor case;
A position detection means for the motor rotor provided on the outer surface of the flange member,
The flange member has a connection opening formed to connect the power supply member and the terminal block from the outside of the external housing, and
The electric motor according to claim 1, wherein when the position detecting means is attached to an outer surface of the flange member, the connection opening is closed by an insulating member provided in the position detecting means. The position detection means is a resolver having a resolver rotor provided around a part of the motor shaft, and a resolver stator disposed so as to surround an outer peripheral surface of the resolver rotor, and
The electric motor according to claim 1, wherein the insulating member is an insulator that insulates a core and a coil of the resolver stator. The position detection means is a resolver having a resolver rotor provided around a part of the motor shaft, and a resolver stator disposed so as to surround an outer peripheral surface of the resolver rotor, and
The electric motor according to claim 1, wherein the insulating member is a cover portion that partially covers a coil of the resolver stator.   4. The electric motor according to claim 2, wherein the insulating member has a shape extending in an outer diameter direction from the resolver stator so as to be in phase with a direction in which the sensor harness of the resolver is led out.   4. The electric motor according to claim 2, wherein the insulating member has a shape extending in an outer diameter direction from the resolver stator so as to have a phase different from a direction in which the resolver sensor harness is led out.   The electric motor according to any one of claims 1 to 5, wherein the sensor harness of the position detection means is led out in an outer diameter direction through a spigot projection provided on the outer surface of the flange member.   An electric power steering apparatus comprising the electric motor according to any one of claims 1 to 6 as a generation source of a steering assist force applied to a steering mechanism. A deceleration mechanism that decelerates and transmits the rotational force of the electric motor to the steering mechanism;
The electric power steering device according to claim 7, further comprising a gear box that houses the speed reduction mechanism and has a motor mounting surface to which the electric motor is fixed.

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