Rotating Electric Machine

Abstract

To provide a rotary electric machine in which the deformation of a case is suppressed.SOLUTION: A motor 20 as a rotary electric machine comprises: a cylindrical stator 21; a front end frame 33 which is arranged in one in the axial direction with respect to the stator 21; a rear end frame 34 which is arranged in the other in the axial direction with respect to the stator 21; a cylindrical case 32 which is sandwiched between the front end frame 33 and the rear end frame 34 and whose inner side is fixed with the stator 21; and a through bolt 38 which fastens the front end frame 33 and the rear end frame 34 on the outer side in the radial direction to the case 32. The case 32 comprises: a stator fixing part 45 which is located in an intermediate portion in the axial direction; a first end 46 which is in contact with the front frame end 33; and a second end 47 which is in contact with the rear frame end 34. The outermost diameter position of a contact end surface 51 is located on the inner side in the radial direction in comparison to the outermost diameter position of the stator fixing part 45.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a rotating electric machine. [Background technology]

[0002] A conventional rotating electric machine is described in, for example, Patent Document 1. The motor disclosed in Patent Document 1 is provided integrally with a control unit. The motor's outer shell is composed of a motor case, a front end frame, and a rear end frame. The front end frame and the rear end frame are fastened to each other by a through bolt with the motor case sandwiched therebetween. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-131463 A Summary of the Invention [Problem to be solved by the invention]

[0004] The axial force of the through bolt generates a moment force that causes the radially outer portion of the rear frame end relative to the motor case to tilt toward the front frame end, which causes compressive stress at the contact point between the motor case and the rear frame end, which may cause the motor case to deform.

[0005] The present invention has been made in consideration of the above-mentioned points, and an object of the present invention is to provide a rotating electric machine in which deformation of the case is suppressed. [Means for solving the problem]

[0006] The rotating electric machine of the present invention includes a cylindrical stator (21) and a second rotor (22) disposed on one side of the stator in the axial direction. 1F Reem End (33) and a second rotor arranged on the other side of the axial direction with respect to the stator. 2FReem End (34) and 1F Reem End and 2F Reem End The stator is fixed to the inside of the cylindrical case (32), and the second rotor is fixed to the outside of the case in the radial direction. 1F Reem End and 2F Reem End and a through bolt (38) that fastens the

[0007] The case has a stator fixing portion (45) located at the middle in the axial direction, and 1F Reem End a first end (46) abutting against the 2F Reem End and a second end portion (47, 48) abutting against the second end portion (47, 48). 2F Reem End The end surface that is in contact with the is defined as the abutting end surface (51), and the 2F Reem End If the portion of the abutment surface that is in contact with the abutment surface is defined as the abutted portion (52), the second end portion is 2F Reem End The abutment portion is fitted to the outside of the cylindrical portion that protrudes in the axial direction radially inside the abutted portion and abuts against the abutted portion. The first end has a flange portion (54) that extends radially outward and abuts the first end frame in the axial direction, and the outer diameter and thickness of the stator fixing portion on the second end frame side from the flange portion are constant. In a first aspect of the present invention, the second end is formed to be thinner than the stator fixing portion. In a second aspect of the present invention, the second end is formed so that the thickness gradually decreases from the stator fixing portion side toward the abutment end face. In the first and second aspects of the present invention, the outermost diameter position of the abutment end face is located radially inward compared to the outermost diameter position of the stator fixing portion. The outermost diameter position refers to the radially outermost position. 。

[0008] As a result, in comparison with the conventional embodiment in which the thickness of the case is constant and the outermost diameter position of the contact end face is the same as the outermost diameter position of the stator fixing part, the compressive stress acting on the second end portion in the present invention is smaller, and deformation of the case can be suppressed. [Brief description of the drawings]

[0009] [Figure 1] 1 is a vertical sectional view of a drive device to which a motor according to a first embodiment is applied. [Diagram 2] Cross-sectional view of line II-II in Figure 1. [Diagram 3] FIG. 2 is a view of the front frame end of FIG. 1 as seen from the direction of arrow III. [Figure 4] 1 as viewed in the direction of arrow IV. [Diagram 5] Enlarged view of part V in Figure 1. [Figure 6] FIG. 7 is an enlarged view of the vicinity of a second end of a case in a motor according to a second embodiment, and corresponds to FIG. 5 of the first embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, a number of embodiments will be described with reference to the drawings. The same reference numerals will be used to designate substantially the same components among the embodiments, and the description thereof will be omitted.

[0011] [First embodiment] 1, the drive device 10 is an electromechanical integrated type in which a motor 20 as a rotating electric machine and a control unit 60 are integrally provided. The control unit 60 controls the motor 20 to generate a desired torque based on information input from the outside and information such as a motor current detected inside the control unit 60. The torque of the motor 20 is output from an output end of a rotating shaft 26 to the outside.

[0012] Hereinafter, a direction parallel to the rotation axis O of the motor 20 will be referred to as an axial direction. A direction perpendicular to the rotation axis O will be referred to as a radial direction. A direction around the rotation axis O will be referred to as a circumferential direction.

[0013] As shown in Figures 1 and 2, the control unit 60 has a board 61 arranged on the rotation axis O on the opposite side of the stator 21 of the motor 20 with respect to the front frame end 33, various electronic components mounted on the board 61, and a cover 62 arranged to cover the board 61 and the various electronic components.

[0014] Although not shown in the figures, the various electronic components mentioned above include, for example, a rotation angle sensor that detects the rotation angle of the rotating shaft 26, a motor drive element that performs a switching operation to switch the power supply state of the motor 20, and a control circuit that performs calculations based on information from the outside and the rotation angle sensor, etc., and issues commands to the motor drive element, etc.

[0015] Motor 20 is a three-phase brushless motor and includes a stator 21, a rotor 25, and a housing 31 that accommodates them. Stator 21 has a stator core 22 fixed to housing 31, and a three-phase winding set 23 assembled to stator core 22. Three-phase winding set 23 is connected to control unit 60 via bus bar 24.

[0016] The rotor 25 has a rotating shaft 26 supported by a rear bearing 35 and a front bearing 36, and a rotor core 27 fixed to the rotating shaft 26. The rotor 25 is provided inside the stator 21 and is rotatable relative to the stator 21. A permanent magnet 37 is provided on one end of the rotating shaft 26.

[0017] The housing 31 has a case 32, a front frame end 33 as a first frame end arranged on one axial side relative to the case 32, and a rear frame end 34 as a second frame end arranged on the other axial side relative to the case 32.

[0018] Here, a first comparative embodiment will be described in which the case is cup-shaped with a bottom on the front side, as disclosed in, for example, Japanese Patent No. 5952542. If the case is cup-shaped, it becomes difficult to secure space for arranging the busbars. If the stack thickness of the stator core is reduced to secure the space, the motor output becomes insufficient. Furthermore, if the busbars are made smaller, heat generation increases. Furthermore, if the overall length of the drive unit is increased, the vehicle mountability decreases, and the vehicle fuel efficiency decreases due to the increased weight. In contrast, in the first embodiment, the case 32 is not cup-shaped but cylindrical. The space without the bottom is used for arranging the busbars.

[0019] As shown in Figs. 1 to 5, the stator 21 is fixed to the inside of a case 32 by shrink fitting. The case 32 is sandwiched between a front end frame 33 and a rear end frame 34. The front end frame 33 has a front fastening portion 41 located radially outward from the case 32. The rear end frame 34 has a rear fastening portion 43 located radially outward from the case 32. The through bolts 38 fasten the front fastening portion 41 and the rear fastening portion 43 radially outward from the case 32.

[0020] Two through bolts 38 are provided. The rear fastening portion 43 has a through hole 44 through which the through bolt 38 is inserted. The front fastening portion 41 has a threaded hole 42 into which the threaded portion of the through bolt 38 is screwed. The two through bolts 38 are disposed at equal intervals in the circumferential direction.

[0021] The case 32 has a stator fixing portion 45 located at the middle in the axial direction, a first end portion 46 abutting against the front end frame 33, and a second end portion 47 abutting against the rear end frame 34. The stator fixing portion 45 needs to have a predetermined thickness (i.e., radial thickness) or more in order to shrink-fit the stator core 22. The second end portion 47 has a shape without a flange portion. This prevents interference between the second end portion 47 and the through bolt 38, and also reduces the weight of the case 32.

[0022] Hereinafter, the end surface of the second end 47 that abuts against the rear frame end 34 will be referred to as an abutting end surface 51. The portion of the rear frame end 34 that abuts against the abutting end surface 51 will be referred to as an abutted portion 52.

[0023] Here, we will explain the problems caused by the axial force of the through bolt 38. When the axial force of the through bolt 38 acts on the rear frame end 34, a moment force is generated that causes the rear fastening portion 43 to fall toward the front frame end 33. As a result, compressive stress is applied to the second end 47 that abuts against the rear frame end 34, particularly to the radially outer portion, which may cause the case 32 to deform.

[0024] In contrast to this, in the first embodiment, the outermost diameter position of the abutment end face 51 is located radially inward compared to the outermost diameter position of the stator fixing portion 45. Specifically, while the inner diameters of the second end portion 47 and the stator fixing portion 45 are the same, the second end portion 47 is formed to be thinner than the stator fixing portion 45. As a result, the compressive stress acting on the second end portion 47 in the first embodiment is smaller than in the second comparative embodiment in which the thickness of the case is constant and the outermost diameter position of the abutment end face is the same as the outermost diameter position of the stator fixing portion.

[0025] If the second end 47 is made thin and the abutment end face 51 is made smaller as described above, there is a concern that the case 32 may buckle and the second end 47 may sink into the abutted portion 52. In response to this, in the first embodiment, the radial width t of the abutment end face 51 is set to satisfy the following formula (1). In formula (1), σ is the stress applied to the abutted portion 52. S is the area of ​​the abutted portion 52. F is the axial force of the through bolt 38. d is the inner diameter of the abutment end face 51. σ cy is the stress at the compressive yield point of the rear end frame 34. The material of the case 32 is, for example, a cold-rolled steel plate, and the material of the rear end frame 34 is an aluminum alloy. The axial force F is set to the maximum within the range in which the through bolt 38 does not break. σ=2F / S=2F / [π{((d+2t) / 2) 2 -(d / 2) 2}]<σ cy (1)

[0026] The front end frame 33 has a fitting portion 53 having a cylindrical surface on the outside. The fitting portion 53 is fitted to another member. When axial forces of the through bolts 38 at two locations on either side of the rotation axis O act on the front end frame 33, there is a concern that the fitting portion 53 may deform into an ellipse. In contrast, in the first embodiment, the first end has a flange portion 54 that extends radially outward and abuts against the front end frame 33 in the axial direction. The outer diameter of the flange portion 54 is approximately the same as the outer diameter of the front end frame 33. The flange portion 54 serves as a resistance portion against deformation of the front end frame 33.

[0027] The flange portion 54 has positioning holes 56 provided in protrusions 55 that protrude radially outward. The positioning holes 56 are used for circumferential positioning when the motor is assembled. The front frame end 33 has positioning portions 57 at positions corresponding to the positioning holes 56. The protrusions 55 are also provided at positions corresponding to the front fastening portions 41 to prevent interference between burrs on the edge of the flange portion 54 and the front fastening portions 41 as much as possible.

[0028] The protrusions 55 are provided at positions corresponding to the two front fastening parts 41, and the protrusions 55 and the positioning holes 56 are provided at positions corresponding to the vicinity of the middle of the two front fastening parts 41 in the circumferential direction. If only one protrusion 55 is provided on the flange part 54 or if the protrusions 55 are provided offset in the circumferential direction, there is a concern that the accuracy of the inner diameter of the case 32 may decrease. In order to ensure the accuracy of the inner diameter, it is effective to provide three or more protrusions 55 arranged at approximately equal intervals in the circumferential direction. In the first embodiment, a protrusion 55 is also provided on the opposite side of the positioning hole 56 across the rotation axis O. The flange part 54 has four protrusions 55 arranged at approximately equal intervals in the circumferential direction. Approximately equal intervals means that a certain degree of interval difference is allowed.

[0029] The flange portion 54 has two notched holes 58, through which the through bolts 38 pass, that are arranged at approximately equal intervals in the circumferential direction. The notched holes 58 are provided in the protrusion 55 at a position corresponding to the front fastening portion 41.

[0030] (effect) As described above, in the first embodiment, the case 32 has the stator fixing portion 45 located at the middle in the axial direction, the first end portion 46 abutting against the front end frame 33, and the second end portion 47 abutting against the rear end frame 34. The outermost diameter position of the abutment end face 51 is located radially inward compared to the outermost diameter position of the stator fixing portion 45. As a result, the compressive stress acting on the second end portion 47 in the first embodiment is smaller than in the first comparative embodiment in which the thickness of the case is constant and the outermost diameter position of the abutment end face is the same as the outermost diameter position of the stator fixing portion. Therefore, deformation of the case 32 can be suppressed.

[0031] In the first embodiment, the second end portion 47 is formed to be thinner than the stator fixing portion 45. This makes it possible to reduce the compressive stress acting on the second end portion 47.

[0032] In the first embodiment, the radial width t of the contact end surface 51 is set so as to satisfy the above formula (1), thereby making it possible to prevent the case 32 from sinking into the rear frame end .

[0033] In the first embodiment, the first end 46 has a flange portion 54 that extends radially outward and abuts against the front end frame 33 in the axial direction. This allows the flange portion 54 to resist deformation of the front end frame 33, making it possible to suppress deformation of the front end frame 33. Furthermore, the flange portion 54 has four protruding portions 55 that protrude radially outward and are arranged at approximately equal intervals in the circumferential direction. This makes it possible to suppress a decrease in the inner diameter accuracy of the case 32 that would be caused by providing only one protruding portion 55.

[0034] In the first embodiment, the flange portion 54 has a plurality of notched holes 58 through which the through bolts 38 pass and which are arranged at approximately equal intervals in the circumferential direction. This makes it possible to minimize the pitch between the two through bolts 38 and suppress deformation of the case 32.

[0035] [Second embodiment] As shown in Fig. 6, in the second embodiment, the outermost diameter position of the abutment end face 51 is located radially inward compared to the outermost diameter position of the stator fixing portion 45, as in the first embodiment. Specifically, while the inner diameters of the second end portion 48 and the stator fixing portion 45 are the same, the second end portion 48 is formed so that the wall thickness gradually decreases from the stator fixing portion 45 side toward the abutment end face 51. The outer wall surface of the second end portion 48 is a tapered surface. This reduces the compressive stress acting on the second end portion 48, as in the first embodiment.

[0036] [Other embodiments] In other embodiments, for example, a large chamfer or rounded portion may be provided at the radially outer corner of the second end so that the outermost diameter position of the abutment end face is positioned radially inward relative to the outermost diameter position of the stator fixing portion.

[0037] In other embodiments, the number of through bolts 38 is not limited to two, but may be three or more.

[0038] The present invention is not limited to the above-described embodiment, and can be embodied in various forms without departing from the spirit of the invention. [Explanation of symbols]

[0039] 20 motor (rotating electric machine), 21 stator, 32 case, 33 1F Reem End , 34th 2F Reem End , 38 through bolt, 45 stator fixing portion, 46 first end portion, 47, 48 second end portion, 51 abutment end surface.

Claims

1. A cylindrical stator (21); A first frame end (33) disposed on one side in the axial direction relative to the stator; A second frame end (34) disposed on the other side of the axial direction relative to the stator; a cylindrical case (32) sandwiched between the first end frame and the second end frame and having the stator fixed thereto; a through bolt (38) that is inserted into a through hole (44) formed in the second frame end on the radially outer side of the case, that is screwed into a screw hole (42) formed in the first frame end, and that fastens the first frame end and the second frame end by having a head abut against the second frame end and being tightened; Equipped with The case has a stator fixing portion (45) located at a middle portion in the axial direction, a first end portion (46) abutting against the first frame end, and a second end portion (47) abutting against the second frame end, If the end surface of the second end portion that abuts against the second end frame is defined as an abutting end surface (51), and the portion of the second end frame that abuts against the abutting end surface is defined as an abutted portion (52), the second end abuts against the abutted portion in a state where the second end is fitted to an outer side of a cylindrical portion of the second end frame that protrudes in the axial direction radially inward from the abutted portion, the first end portion has a flange portion (54) extending radially outward and abutting against the first end frame in the axial direction, and an outer diameter and a wall thickness of the stator fixing portion on the second end frame side relative to the flange portion are constant, The second end portion is formed to be thinner than the stator fixing portion, a rotating electric machine, wherein an outermost diameter position of the contact end face is located radially inward compared to an outermost diameter position of the stator fixing portion.

2. A cylindrical stator (21); A first frame end (33) disposed on one side in the axial direction relative to the stator; A second frame end (34) disposed on the other side of the axial direction relative to the stator; a cylindrical case (32) sandwiched between the first end frame and the second end frame and having the stator fixed thereto; a through bolt (38) that is inserted into a through hole (44) formed in the second frame end on the radially outer side of the case, that is screwed into a screw hole (42) formed in the first frame end, and that fastens the first frame end and the second frame end by having a head abut against the second frame end and being tightened; Equipped with The case has a stator fixing portion (45) located at a middle portion in the axial direction, a first end portion (46) abutting against the first frame end, and a second end portion (48) abutting against the second frame end, If the end surface of the second end portion that abuts against the second end frame is defined as an abutting end surface (51), and the portion of the second end frame that abuts against the abutting end surface is defined as an abutted portion (52), the second end abuts against the abutted portion in a state where the second end is fitted to an outer side of a cylindrical portion of the second end frame that protrudes in the axial direction radially inward from the abutted portion, the first end portion has a flange portion (54) extending radially outward and abutting against the first end frame in the axial direction, and an outer diameter and a wall thickness of the stator fixing portion on the second end frame side relative to the flange portion are constant, the second end portion is formed so that the thickness gradually decreases from the stator fixing portion side toward the contact end surface, a rotating electric machine, wherein an outermost diameter position of the contact end face is located radially inward compared to an outermost diameter position of the stator fixing portion.

3. A rotating electric motor as described in claim 1 or 2, wherein the flange portion has three or more convex portions (55) protruding radially outward and arranged at approximately equal intervals in the circumferential direction.

4. 4. The rotating electric machine according to claim 3, wherein the flange portion has a plurality of notched holes (58) through which the through bolts pass and which are arranged at substantially equal intervals in the circumferential direction.

5. Let the stress acting on the abutted portion be σ, the area of ​​the abutted portion be S, the axial force of the through bolt be F, the inner diameter of the abutting end face be d, the radial width of the abutting end face be t, and the stress at the compressive yield point of the second frame end be σ cy , The radial width t is σ=2F / S=2F / [π{((d+2t) / 2) 2 -(d / 2) 2}]<σ cy The rotating electric machine according to any one of claims 1 to 4, wherein the above is set to satisfy the above.

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