JP2012115027A - Installation method of stator core of electric motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an installation method of a stator core of an electric motor capable of attaching the stator core to the inner periphery of a core holder without difficulty and regulating the axial movement of the stator core for the core holder even by the heat deformation of the core holder or the stator core.SOLUTION: An installation method in which a stator core 41 of an electric motor is installed on the inner periphery of a core holder 44 includes a step of engaging the outer peripheral part of the stator core with a recess 37 formed in a cylindrical part 44a of the core holder. The recess is partitioned by a first wall 37a, a second wall 37b, and bottom part 37c, and the distance between the first wall and the second wall in room temperature is set so that the outer peripheral part of the stator core is engaged in the recess.

Description

  The present invention relates to a stator core mounting method for mounting a stator core of an electric motor to a core holder.

  A hybrid vehicle drive device including two drive sources of an engine and an electric motor is disclosed in Patent Document 1. In the device described in Patent Document 1, the stator assembly of the electric motor is fixed by press-fitting with a predetermined tightening margin to the inner periphery of the stator core holder fixed to the housing.

JP 2010-57260 A

  As disclosed in Patent Document 1, in the structure in which the stator assembly is fixed by press-fitting, when the tightening margin is increased in order to improve the fixing force, the laminated steel plate constituting the stator assembly is deformed. Cause problems. On the other hand, if the tightening margin is reduced, the vibration of the motor is applied, so that fretting occurs between the stator assembly and the stator core holder, and the stator assembly may not be fixed due to fretting wear. .

  For this reason, in a structure in which the stator assembly is fixed by press-fitting, it is necessary to strictly manage the tightening allowance so that deformation of the laminated steel sheet and occurrence of fretting can be suppressed.

  The present invention has been made in view of the above-described problems, and allows the stator core to be mounted on the inner periphery of the core holder without difficulty, and the axial movement of the stator core relative to the core holder can be restricted by thermal deformation or the like of the core holder or the stator core. An object of the present invention is to provide a method for mounting a stator core of an electric motor.

  In order to solve the above-mentioned problems, the invention according to claim 1 is characterized in that an attachment method for attaching a stator core of an electric motor to an inner periphery of a core holder is as follows. The step of engaging.

  A feature of the invention according to claim 2 is that, in claim 1, the linear expansion coefficient of the core holder is larger than the linear expansion coefficient of the stator core.

  According to a third aspect of the present invention, in the first or second aspect, the concave portion is defined by a first wall, a second wall, and a bottom portion, and between the first wall and the second wall at room temperature. This distance is set so that the outer peripheral portion of the stator core is fitted in the recess.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, the concave portion is defined by a first wall, a second wall, and a bottom portion, the core holder has an annular shape, and the core holder The length of the first wall and the second wall in the radial direction is set to 0.5 to 0.8 mm.

  According to the first aspect of the present invention, the attachment method for attaching the stator core of the electric motor to the inner periphery of the core holder includes the step of engaging the outer periphery of the stator core in the recess formed in the cylindrical portion of the core holder. Can be attached to the inner periphery of the core holder by shrink fitting or cold fitting, and the engagement of the outer periphery of the stator core to the recess of the core holder does not increase the tightening margin of the laminated steel sheets constituting the stator core. However, it is possible to restrict the movement of the stator core in the axial direction.

  According to the invention of claim 2, since the linear expansion coefficient of the core holder is larger than the linear expansion coefficient of the stator core, the inner diameter of the cylindrical portion of the core holder can be easily expanded from the outer diameter of the stator core.

  According to the invention of claim 3, the recess is defined by the first wall, the second wall, and the bottom, and the distance between the first wall and the second wall at room temperature is such that the outer periphery of the stator core is in the recess. Since it is set to fit, the axial movement of the stator core can be reliably restricted.

  According to the invention of claim 4, the recess is defined by the first wall, the second wall, and the bottom, the core holder has an annular shape, and the length of the first wall and the second wall in the radial direction of the core holder is 0. Since the core holder or stator core is thermally expanded or contracted, the outer periphery of the stator core does not deviate from the inside of the recess of the core holder, and the stator core moves in the axial direction. Can be reliably regulated.

It is sectional drawing of the drive device for hybrid vehicles which shows embodiment of this invention. It is a front view which shows the stator core of an electric motor. It is a figure which shows the stator core with which the core holder was mounted | worn. It is a figure which shows the assembly | attachment state of a stator core.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an example in which an electric motor having a stator core attached to a housing by the attachment method of the present invention is applied to a hybrid vehicle drive device 10. The hybrid vehicle drive device 10 is disposed between a vehicle engine 11 and an automatic transmission 12 and includes an electric motor 13 and a clutch device 14. The electric motor 13 includes a stator 15 and a rotor 16. The stator 15 is fixed to the housing 20 of the hybrid vehicle drive device 10 as described later, and the rotor 16 is connected to an input shaft 17 connected to the engine 11 via a clutch device 14. It is connected so that it can be separated. Further, the rotor 16 of the electric motor 13 is connected to an output shaft 18, and the output shaft 18 is connected to a center piece 19 that forms the input shaft of the automatic transmission 12. The automatic transmission 12 includes a torque converter and a transmission (not shown), and the output of the torque converter is transmitted to the drive wheels of the vehicle via the transmission.

  The hybrid vehicle drive device 10 includes a housing 20 that surrounds the electric motor 13 and the clutch device 14. The housing 20 has an outer peripheral wall portion 20a that forms an outer shape, and a rear side wall portion 20b that is interposed between the electric motor 13, the clutch device 14, and the automatic transmission 12, and the engine 11 side is opened.

  On the engine 11 side of the housing 20, a front housing 21 that forms a lid portion that closes the opening of the housing 20 is disposed, and the front housing 21 is fixed to the housing 20 with bolts 35. A through-hole through which the input shaft 17 passes is provided at the center of the front housing 21, and a bearing is provided so that the input shaft 17 can rotate around the rotation axis O1 by a ball bearing 22 disposed at the center. Has been.

  A through hole through which the output shaft 18 passes is provided at the center of the rear side wall portion 20b of the housing 20, and the output shaft 18 is rotated around the rotation axis O1 by a ball bearing 23 disposed at the center. It is rotatably supported. A center piece 19 of the automatic transmission 12 is rotationally connected to the output shaft 18 concentrically with the output shaft 18.

  The output shaft 18 has a substantially inverted S-shaped cross section in the rotation axis direction, and a clutch drum portion 25 is formed on the outer periphery. The rotor 16 of the electric motor 13 is disposed on the outer periphery of the clutch drum portion 25. . A plurality of annular outer clutch plates 27 are engaged with the inner periphery of the clutch drum portion 25 so as to be movable in the direction of the rotation axis while restricting relative rotation. A plurality of annular inner clutch plates 28 are disposed between the outer clutch plates 27, and these inner clutch plates 28 are rotated relative to the outer periphery of the clutch hub portion 29 protruding from the outer periphery of the input shaft 17. And is engaged so as to be movable in the direction of the rotation axis.

  A cylinder 32 in which a piston 31 is slidably fitted is formed in the output shaft 18. The piston 31 presses the outer clutch plate 27 in a direction to join the inner clutch plate 28 by the urging force of the coil spring 33. Further, the piston 31 is slid against the urging force of the coil spring 33 by the pressure fluid supplied to the cylinder 32, and the joining of the outer clutch plate 28 and the inner clutch plate 29 is released.

  The above-described outer clutch plate 27, inner clutch plate 28, piston 31, cylinder 32, coil spring 33, and the like constitute the clutch device 14.

  Next, the electric motor 13 will be described. The electric motor 13 includes a brushless DC motor or the like, and is disposed between the inner periphery of the outer peripheral wall portion 20 a of the housing 20 and the outer periphery of the clutch drum portion 25 of the output shaft 18. The electric motor 13 includes a stator core 41 constituting the stator 15 and a rotor core 42 constituting the rotor 16, and the rotor core 42 is rotatably supported on the inner peripheral side of the stator core 41.

  As shown in FIG. 2, the stator 15 includes a stator core 41 in which a plurality of divided cores 41 a are arranged in an annular shape and an annular shape that is attached to the outer periphery of the stator core 41 and integrates the plurality of divided cores 41 a. A core holder 44 is provided. A coil is wound around each tooth portion 41b of the split core 41a, although not shown. As shown in FIG. 3, the stator core 41 (divided core 41 a) is composed of a plurality of laminated steel plates 43 laminated in the axial direction of the input shaft 17.

  As shown in an enlarged view in FIG. 3, the core holder 44 is formed by bending a cylindrical portion 44 a housed in the outer peripheral wall portion 20 a of the housing 20 and one end of the cylindrical portion 44 a outward in the radial direction of the rotor 16. 1 and a second flange portion 44c formed by bending the other end of the cylindrical portion 44a radially inward of the rotor 16, and the first flange portion 44b is a bolt 36. By this, it is fixed to the housing 20. The core holder 44 is made of a material (for example, aluminum-based metal) having a larger linear expansion coefficient than the stator core 41 (laminated steel plate 43).

  A concave portion 37 that engages with the outer peripheral portion of the stator core 41 and positions the stator core 41 in the axial direction is formed on the inner periphery of the cylindrical portion 44a of the core holder 44 to which the stator core 41 is mounted. The concave portion 37 is partitioned by a first wall 37a, a second wall 37b, and a bottom portion 37c. At this time, the axial length of the concave portion 37 at normal temperature, that is, the distance between the first wall 37a and the second wall 37b is such that the outer peripheral portion of the stator core 41 fits into the concave portion 37. The length (step) of the first wall 37a and the second wall 37b in the radial direction of the core holder 44 is the same as or slightly larger than the axial length. Is set to 0.5 to 0.8 mm so as not to deviate from the inside of the recess 37 of the core holder 44.

  The plurality of laminated steel plates 43 are integrated by a known dowel caulking, and in this state, are attached to the inner periphery of the cylindrical portion 44a of the core holder 44 by shrink fitting as will be described later. Here, the outer diameter of the laminated steel plate 43 of the annular stator core 41 in an annularly arranged and integrated state is larger than the inner diameter of the cylindrical portion 44a of the core holder 44 at the ordinary temperature, and the bottom 37c of the concave portion 37 is integrated. The inner periphery of the stator core 41 and the inner periphery of the recess 37 are fitted with a clearance fit or an intermediate fit.

  The rotor core 42 constituting the rotor 16 of the electric motor 13 is composed of a plurality of laminated steel plates 45 laminated in the axial direction of the input shaft 17, and the rotor core 42 has a plurality of circumferential permanent magnets 46 (FIG. 1). Reference) is embedded. As shown in FIG. 1, a pair of end plates 47, 48 are arranged at both ends in the axial direction of the rotor core 42 so as to sandwich the rotor core 42, and the permanent magnet 46 is separated from the rotor core 42 by these end plates 47, 48. I try not to jump out. The rotor core 42 and the end plates 47 and 48 are integrally fastened by a plurality of caulking pins 50 on the circumference.

  One end plate 47 has an extending portion 47 a extending radially inward, and the extending portion 47 a is fixed to the side end surface of the output shaft 18 by a bolt 52. As a result, the rotor 16 (rotor core 42) of the electric motor 13 is supported by the housing 20 so as to be rotatable integrally with the output shaft 18. The rotor core 42 is also configured by arranging a plurality of divided cores in an annular shape, like the stator core 41.

  Next, a method of attaching the stator core 41 of the above-described electric motor 13 to the core holder 44 and attaching it to the housing 20 will be described.

  The laminated steel plates 43 constituting the split core 41a are integrated in advance by doweling to constitute an annular stator core 41. In this state, the core holder 44 is warmed and thermally expanded, so that the inner diameter of the cylindrical portion 44a is larger than the outer diameter of the stator core 41 (laminated steel plate 43). Subsequently, as shown in FIG. 4, the stator core 41 is mounted in the axial direction to a position corresponding to the concave portion 37 formed on the inner periphery of the cylindrical portion 44 a of the core holder 44. Thereafter, by returning the core holder 44 to room temperature, the inner diameter of the cylindrical portion 44a is reduced, and the outer peripheral portion of the stator core 41 is engaged in the concave portion 37 of the cylindrical portion 44a, and the first wall 37a and the second wall 37b It is positioned so that it cannot move in the axial direction by engagement. At this time, the stator core 41 is preferably fitted into the concave portion 37 of the core holder 44 by a clearance fit or an intermediate fit, thereby suppressing the deformation of the stator core 41 caused by increasing the tightening margin as in the prior art. Can do.

  Further, since the length (step) of the first wall 37a and the second wall 37b in the radial direction of the core holder 44 is set to 0.5 to 0.8 mm, the linear expansion coefficient is increased by the temperature rise accompanying the driving of the electric motor 13. Even if the large core holder 44 is thermally expanded with respect to the stator core 41, the stator core 41 does not deviate from the engagement between the first wall 37a and the second wall 37b of the recess 37, and the axial movement is restricted. Conversely, even if the core holder 44 and the stator core 41 are thermally contracted due to a decrease in the outside air temperature, there is no allowance for deforming the stator core 41.

  When the vehicle is in a stopped state, the hybrid vehicle drive device 10 configured as described above turns on the ignition switch (not shown) and the driver steps on the accelerator pedal (at the time of low throttle opening). A current flows from the motor (not shown) to the electric motor 13, and the electric motor 13 functions as a drive motor. Then, the rotational driving force is transmitted to the torque converter through the output shaft 18 and is increased by a predetermined torque ratio by the torque converter and then transmitted to the driving wheel through the transmission.

  When the vehicle starts, the fuel injection device of the engine 11 does not operate and the engine 11 is in a stopped state. Then, the vehicle starts by only the driving force from the electric motor 13. At this time, the clutch device 14 is disengaged. Even in a region where the engine efficiency is poor, such as when the engine 11 is under a low load or under an extremely low load, the engine 11 is stopped, the vehicle runs only with the electric motor 13, and the clutch device 14 is disengaged.

  Further, even when the vehicle is just after starting and the speed is relatively low, the engine 11 is started when accelerating or climbing. In other words, when the accelerator pedal is stepped on to accelerate or climb up and the throttle is opened more than a certain degree of opening, the fuel injection device is activated and the ignition plug is ignited and fixed to the housing 20 (see FIG. (Not shown) is driven, and the engine 11 is started. At this time, when the clutch device 14 is engaged, the rotational driving force of the input shaft 17 is transmitted to the output shaft 18 via the clutch device 14. As a result, the driving forces of both the engine 11 and the electric motor 13 are added, and the vehicle travels with a large driving force. When the vehicle is in a steady high-speed traveling state, the electric motor 13 is operated without load (the motor output is controlled so as to cancel the torque generated by the counter electromotive force generated in the motor), and the electric motor 13 is idled. As a result, the vehicle travels solely by the driving force of the engine 11 while the clutch device 14 remains engaged.

  According to the mounting method of the stator core 41 of the electric motor according to the above-described embodiment, the stator core 41 can be mounted on the inner periphery of the core holder 44 by shrink fitting or the like, and the stator core into the recess 37 of the core holder 44. With the engagement of the outer peripheral portion 41, it is possible to restrict the movement of the stator core 41 in the axial direction without raising the tightening allowance of the laminated steel plate 43 constituting the stator core 41.

  Further, since the distance between the first wall 37a and the second wall 37b of the concave portion 37 of the core holder 44 at normal temperature is set so that the outer peripheral portion of the stator core 41 fits into the concave portion 37, the axial direction of the stator core 41 The movement can be reliably regulated. Furthermore, since the lengths of the first wall 37a and the second wall 37b in the radial direction of the core holder 44 are set to 0.5 to 0.8 mm, even if the core holder 44 or the stator core 41 is thermally expanded or contracted, the stator core The outer peripheral portion of 41 does not deviate from the inside of the concave portion 37 of the core holder 44, and the axial movement of the stator core 41 can be reliably restricted.

  In the above-described embodiment, an example in which the outer peripheral portion of the stator core 41 is engaged in the concave portion 37 of the cylindrical portion 44a of the core holder 44 by shrink fitting that warms the core holder 44 and expands the inner periphery of the cylindrical portion 44a will be described. However, conversely, the outer peripheral portion of the stator core 41 may be engaged with the concave portion 37 of the core holder 44 by cold fitting that cools the stator core 41 and reduces the outer diameter of the laminated steel plate 43.

  In the above-described embodiment, the example in which the electric motor 13 is applied to the hybrid vehicle drive device 10 has been described. However, the present invention attaches the stator core 41 made of the laminated steel plate 43 in the recess of the annular core holder 44. Is applicable.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention described in the claims. It is.

  DESCRIPTION OF SYMBOLS 11 ... Engine, 12 ... Automatic transmission, 13 ... Electric motor, 14 ... Clutch device, 15 ... Stator, 16 ... Rotor, 17 ... Input shaft, 18 ... Output shaft, 20 ... Housing, 37 ... Recess, 37a ... No. 1 wall, 37b ... 2nd wall, 37c ... bottom part, 41 ... stator core, 42 ... rotor core, 43 ... laminated steel plate, 44 ... core holder, 44a ... cylindrical part.

Claims (4)

The mounting method to attach the stator core of the motor to the inner circumference of the core holder is
A method for attaching a stator core of an electric motor, comprising a step of engaging an outer peripheral portion of the stator core in a recess formed in a cylindrical portion of the core holder.   2. The method for attaching a stator core of an electric motor according to claim 1, wherein the linear expansion coefficient of the core holder is larger than the linear expansion coefficient of the stator core.   In Claim 1 or Claim 2, the above-mentioned crevice is divided by the 1st wall, the 2nd wall, and the bottom, and the distance between the 1st wall and the 2nd wall in normal temperature is the outer peripheral part of the stator core A method for attaching a stator core of an electric motor set to fit in the recess. In any 1 item | term of the Claims 1 thru | or 3, The said recessed part is divided by the 1st wall, the 2nd wall, and the bottom part, The said core holder comprises cyclic | annular form, The said 1st wall regarding the radial direction of the said core holder, and the said The method of attaching the stator core of the electric motor, wherein the length of the second wall is set to 0.5 to 0.8 mm.