Rotary electric machine

Abstract

To reduce work relating to a position adjustment of a rotary shaft.SOLUTION: A rotary electric machine comprises: a stator; a rotor which is rotatably provided inside the stator; a rotary shaft which is rotatable integrally with the rotor; a first bearing and a second bearing which are provided in both end side portions of the rotary shaft and rotatably support the rotary shaft; a bracket inside which the rotary shaft is passed and which holds the second bearing movably in an axial direction of the rotary shaft and includes inside a female screw part of which the screw-in direction becomes the axial direction of the rotary shaft; a pressing member which elastically presses the first bearing to the side of the second bearing; a first member inside which the rotary shaft is passed and which is provided inside the bracket, includes a male screw part which is meshed with the female screw part, and moves in the axial direction of the rotary shaft by being rotated in a rotation direction of the rotary shaft; and a second member which is fixed to the first member and fixed to the bracket in a removable manner.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] This embodiment relates to a rotating electrical machine.

Background Art

[0002] The position of the rotating shaft of a rotating electrical machine greatly depends on the machining accuracy of each structure constituting the rotating electrical machine, and it is difficult to measure the accurate position unless it is in an assembled state. This becomes a prominent problem particularly in situations where the position adjustment of the rotating shaft is important.

[0003] In a rotating electrical machine, the accuracy of the position of the rotating shaft depends on the machining accuracy of each component of the rotating electrical machine. Therefore, in the conventional configuration, the position of the rotating shaft is measured after assembly. And when the position accuracy of the rotating shaft does not meet the requirements, operations such as disassembling the rotating electrical machine for adjustment and then reassembling it are necessary.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the operations related to disassembly and reassembly for the position adjustment of the rotating shaft consume man-hours and time, and reduce the production efficiency of the rotating electrical machine. Also, disassembly and reassembly increase the risk of wear and damage to each component constituting the rotating electrical machine, and may have an adverse effect on the overall reliability of the product.

[0006] This embodiment has been made in view of the above circumstances, and its object is to provide a rotating electrical machine capable of reducing the operations related to the position adjustment of the rotating shaft.

Means for Solving the Problems

[0007] The rotating electrical machine according to the embodiment includes a stator, a rotor rotatably provided inside the stator, a rotating shaft rotatable integrally with the rotor, a first bearing and a second bearing provided at both end portions of the rotating shaft to rotatably support the rotating shaft, a bracket having a female screw portion inside which the rotating shaft passes and which holds the second bearing movably in the axial direction of the rotating shaft and having an internal thread direction along the axial direction of the rotating shaft, a pressing member that elastically presses the first bearing toward the second bearing side, a first member that has a male screw portion provided inside and meshes with the female screw portion and moves in the axial direction of the rotating shaft by rotating in the rotation direction of the rotating shaft, and a second member fixed to the first member and removably fixed to the bracket.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Mode for Carrying Out the Invention

[0009] Hereinafter, a rotating electrical machine according to an embodiment will be described with reference to the drawings. The rotating electrical machine of this embodiment can be applied to, for example, an induction motor driven by an inverter, but the application target is not limited to this. First, with reference to FIGS. 1 to 3, the mechanical configuration of the rotating electrical machine 10 will be described. The rotating electrical machine 10 shown in FIG. 1 includes a stator 11, a rotor 12, a rotating shaft 13, a case 14, bearings 20, and a bracket 30. In the following description, the direction parallel to the center O of the rotating shaft 13 is referred to as the axial direction. Also, the direction orthogonal to the center O is referred to as the radial direction.

[0010] In the case of this embodiment, a part of the stator 11, the rotor 12, and the rotating shaft 13 is accommodated in the case 14. The stator 11 is fixed inside the case 14. The stator 11 can be configured to have, for example, a stator core 111 and a stator winding 112. The stator core 111 is configured, for example, in a cylindrical shape and is formed by laminating a plurality of disk-shaped electromagnetic steel sheets. The stator winding 112 is wound around the stator core 111.

[0011] The rotor 12 is provided inside the stator 11 with a gap therebetween with respect to the stator 11 and is configured to be rotatable. That is, in this embodiment, the rotating electrical machine 10 can be configured as, for example, an inner rotor type rotating electrical machine. The rotor 12 can be configured to have a cage-type conductor, a configuration having a rotor core and a winding, or a configuration having a rotor core and a permanent magnet.

[0012] The rotating shaft 13 is provided through the center of the rotor 12 and is configured to be rotatable integrally with the rotor 12. Both end portions of the rotating shaft 13 are rotatably supported by the bracket 30 via the bearings 20, respectively. The rotating shaft 13 is formed in a so-called stepped shape at both ends, for example, with the outer diameter of the central portion being larger than the outer diameters of both end portions.

[0013] Case 14 constitutes the outer shell of the rotating electrical machine 10 and is configured in a cylindrical shape as a whole. Case 14 has an opening 141 on at least one end side in the axial direction of the rotating shaft 13. The opening 141 communicates the inside and outside of case 14 and is sized to allow the stator 11 and the rotor 12 to be inserted and removed. In the case of this embodiment, case 14 has openings 141 on both end sides in the axial direction of the rotating shaft 13. Case 14 is made of a conductive metal material, such as a casting of iron or the like. Case 14 can be made of, for example, FC200, which is a kind of gray cast iron excellent in forgeability.

[0014] Bearings 20 are provided at both end portions of the rotating shaft 13 and rotatably support the rotating shaft 13. The bearings 20 can be configured by, for example, ball bearings or the like. As also shown in FIG. 3, the outer ring 21 of the bearing 20 is fixed inside the bracket 30. Further, the rotating shaft 13 is fitted into the inner ring 22 of the bearing 20, and the inner ring 22 of the bearing 20 is locked to the stepped portion of the rotating shaft 13. In this case, the two bearings 20 are respectively provided on both end sides in the axial direction of the rotating shaft 13 with respect to the rotor 12.

[0015] In the following description, when distinguishing between the two bearings 20, one may be referred to as the first bearing 201 and the other may be referred to as the second bearing 202. For example, a cooling fan or the like is attached to one side, that is, the first bearing 201 side, of both ends of the rotating shaft 13, and a load, for example, is attached to the other side, that is, the second bearing 202 side.

[0016] The bracket 30 is composed of a member having rigidity such as metal or reinforced resin. The bracket 30 has the bearing 20 attached thereto and is provided in the case 14 to close the opening 141. In this case, for the bracket 30 to close the opening 141, it suffices that the bracket 30 covers most of the opening 141, and it is not necessary to completely seal the opening 141 in a watertight or airtight manner. The brackets 30 are provided, for example, on both sides of the case 14. In the following description, when distinguishing between the two brackets 30, one may be referred to as the first bracket 301 and the other as the second bracket 302.

[0017] The rotation shaft 13 passes through the inside of the bracket 30, and the bearing 20 is held movably in the axial direction of the rotation shaft 13, that is, in the direction of arrow A in FIG. 1. In this case, the outer peripheral surface of the bearing 20 is configured to be slidable in the axial direction of the rotation shaft 13 with respect to the inner peripheral surface of the bracket 30. Among the two brackets 30, the first bracket 301 houses the first bearing 201. Also, the second bracket 302 houses the second bearing 202.

[0018] Inside the second bracket 302, as shown in FIG. 3, a stepped hole having a large-diameter portion 31 with a large inner diameter and a small-diameter portion 32 with an inner diameter smaller than that of the large-diameter portion 31 is formed. The large-diameter portion 31 is located closer to the center in the longitudinal direction of the rotation shaft 13 than the small-diameter portion 32. In other words, the small-diameter portion 32 is located closer to the end of the rotation shaft 13 than the large-diameter portion 31. The second bearing 202 is housed inside the large-diameter portion 31.

[0019] Also, the second bracket 302 has a female screw portion 33. The female screw portion 33 is formed on the cylindrical inner surface passing through the second bracket 302. The screwing direction of the female screw portion 33 coincides with the axial direction of the rotation shaft 13. The female screw portion 33 is provided from the outer end surface of the second bracket 302 to a middle portion in the axial direction of the rotation shaft 13. In the case of this embodiment, the female screw portion 33 is provided on the inner surface of the small-diameter portion 32.

[0020] The rotating electrical machine 10 further includes a pressing member 40, a first member 50, and a second member 60. The pressing member 40 is located inside the first bracket 301 and is provided between the first bracket 301 and the first bearing 201. The pressing member 40 is in contact with the first bracket 301 and the first bearing 201, and applies an elastic force to the first bearing 201 in the axial direction of the rotating shaft 13 toward the second bracket 302 side. Thereby, the pressing member 40 elastically presses the first bearing 201 toward the second bearing 202 side. The pressing member 40 can be constituted by, for example, a spring washer or a coil spring into which the rotating shaft 13 can be inserted inside.

[0021] The first member 50 is constituted by a member having rigidity such as metal or reinforced resin. As a whole, the first member 50 is formed in a stepped cylindrical shape having a large-diameter portion 51 with a large outer diameter and a small-diameter portion 52 with an outer diameter smaller than that of the large-diameter portion 51. As shown in FIG. 3, the rotating shaft 13 passes through the inside of the cylindrical shape of the first member 50. Further, the first member 50 is provided inside the second bracket 302. In this case, the inner diameter dimension of the small-diameter portion 32 of the second bracket 302 substantially coincides with the outer diameter dimension of the small-diameter portion 52 of the first member 50.

[0022] Also, the outer diameter dimension of the large-diameter portion 51 of the first member 50 is set to be equal to or smaller than the inner diameter dimension of the large-diameter portion 31 of the second bracket 302. In this case, the outer peripheral surface of the large-diameter portion 51 of the first member 50 may be in slidable contact with the large-diameter portion 31 of the second bracket 302, or may be separated therefrom.

[0023] The first member 50 has a male screw portion 53. The male screw portion 53 is a male screw that meshes with the female screw portion 33 of the second bracket 302. In the case of the present embodiment, the male screw portion 53 is formed on the outer surface of the small-diameter portion 52 of the first member 50. The first member 50 is configured to be movable in the axial direction of the rotating shaft 13 by rotating along the rotation direction of the rotating shaft 13.

[0024] Also, the side of the first member 50 on the second bearing 202 side is configured to be able to contact the outer ring 21 of the second bearing 202. In this case, the first member 50 is configured not to inhibit the rotation of the inner ring 22 of the second bearing 202. And when the side of the first member 50 on the second bearing 202 side contacts the outer ring 21 of the second bearing 202, the movement of the second bearing 202 toward the first member 50 side is restricted.

[0025] The second member 60 is composed of a member having rigidity such as metal or reinforced resin, and as shown in FIG. 2, it is formed in an annular plate shape as a whole. The second member 60 is attached around the rotating shaft 13 and outside the second bracket 302 and the first member 50. The second member 60 is fixed to the first member 50 and removably fixed to the second bracket 302. For this reason, the first member 50 is removably fixed to the second bracket 302 via the second member 60.

[0026] When the first member 50 and the second member 60 are made of metal, the first member 50 and the second member 60 may be fixed to each other in a non-removable manner, for example, by welding or the like. In the case of this embodiment, the first member 50 and the second member 60 are fixed by a first bolt 71 as shown in FIG. 2. In this case, the first member 50 has a plurality, for example, four female screw holes 54. The female screw holes 54 are provided at equal intervals, for example, at 90-degree intervals, on concentric circles centered on the axis of the rotating shaft 13.

[0027] Also, the second member 60 has a plurality, in this case, four first through holes 61 corresponding to the female screw holes 54. And the first bolt 71 is passed through the first through hole 61 from the outside of the second member 60 and screwed into the female screw hole 54. Thereby, the first member 50 and the second member 60 are removably fixed to each other by the first bolt 71.

[0028] Also, as shown in FIG. 2, the second bracket 302 and the second member 60 are fixed by the second bolt 72. In this case, the second bracket 302 has a plurality of, for example, two female screw holes 34. The female screw holes 34 are provided at equal intervals, for example, at 180-degree intervals, on concentric circles centered on the axis of the rotating shaft 13.

[0029] The second member 60 has a plurality of, in this case, eight second through holes 62 corresponding to the female screw holes 34. Then, the second bolts 72 are passed through the second through holes 62 from the outside of the second member 60 and screwed into the female screw holes 34 of the second bracket 302. Thereby, the second member 60 and the second bracket 302 are removably fixed to each other by the second bolts 72.

[0030] The eight second through holes 62 are arranged at equal intervals on the circumference centered on the axis O of the rotating shaft 13 and on the same circumference as the circle on which the female screw holes 34 are arranged. That is, the eight second through holes 62 are arranged, for example, at 45-degree intervals. And the number of the second through holes 62 provided in the second member 60 is set to be larger than the number of the female screw holes 34 provided in the second bracket 302. In other words, the number of the female screw holes 34 provided in the second bracket 302 is set to be smaller than the number of the second through holes 62 provided in the second member 60.

[0031] In this embodiment, the number of the second through holes 62 provided in the second member 60 is eight. On the other hand, the number of the female screw holes 34 provided in the second bracket 302 is two. In this case, two of the eight second through holes 62 located diagonally on the circumference correspond to the two female screw holes 34. Therefore, the second member 60 can be rotated and fixed in 45-degree increments around the axis O of the rotating shaft 13.

[0032] Next, with reference to FIGS. 4 and 5, the procedure for adjusting the position of the rotating shaft 13 will be described. In the rotating electrical machine 10 of the present embodiment, the position of the rotating shaft 13 can be adjusted in a state where the stator 11, the rotor 12, the rotating shaft 13, the case 14, the bearings 20, and the bracket 30 are assembled. In adjusting the position of the rotating shaft 13, first, as shown in FIGS. 3 and 4, the operator removes the second bolt 72 from the second bracket 302 to release the fixing of the first member 50 and the second member 60 to the second bracket 302. Then, the operator rotates the first member 50 and the second member 60 in the rotational direction of the rotating shaft 13. Then, as shown in FIG. 4, the first member 50 and the second member 60 move in the axial direction of the rotating shaft 13 with respect to the second bracket 302.

[0033] Here, when it is desired to move the rotating shaft 13 toward the second bracket 302 side, that is, the right side in the plane of FIG. 1, the operator turns the first member 50 and the second member 60 counterclockwise as viewed from the X2 direction in FIG. 1, for example. In the present embodiment, the operator rotates the first member 50 and the second member 60 in increments of, for example, 45 degrees. As a result, as indicated by the white arrow in FIG. 4, the first member 50 and the second member 60 move in a direction away from the second bearing 202. Then, the rotating shaft 13 moves toward the first member 50 side together with the first bearing 201 and the second bearing 202 as indicated by the white arrow in FIG. 5 due to the pressing force of the pressing member 40 provided on the first bracket 301. Then, the outer ring 21 of the second bearing 202 contacts the first member 50, thereby determining the positions of the bearing 20 and the rotating shaft 13.

[0034] On the other hand, when it is desired to move the rotation axis 13 toward the first bracket 301, the operator rotates the first member 50 and the second member 60 clockwise as viewed from the X2 direction in FIG. 1, for example. As a result, the first member 50 and the second member 60 move in a direction opposite to the direction indicated by the white arrows in FIGS. 4 and 5. Then, the second bearing 202 is pushed toward the first bracket 301 by the movement of the first member 50, and thereby, together with the second bearing 202, the first bearing 201 and the rotation axis 13 are pushed toward the first bracket 301. And since the rotation axis 13 receives a force in the direction indicated by the white arrow in FIG. 5 from the pressing member 40 provided on the first bracket 301 via the first bearing 201, the second bearing 202 is pressed against the first member 50. Thereby, depending on the position of the first member 50, the positions of the bearing 20 and the rotation axis 13 are determined.

[0035] Then, when the operator finishes adjusting the position of the shaft end of the rotation axis 13, as shown in FIG. 5, the operator passes the second bolt 72 through the second through-hole 62 of the second member 60 and threads it into the female screw hole 34 of the second bracket 302 to fix the first member 50 and the second member 60 to the second bracket 302. By this second bolt 72, the rotation of the first member 50 and the second member 60 is restricted, and the positions of the first member 50 and the second member 60 and the position of the rotation axis 13 are fixed. Thereby, the adjustment of the position of the rotation axis 13 is completed. Incidentally, if necessary, a spacer or the like for filling the gap between the second bracket 302 and the second member 60 may be provided.

[0036] According to the embodiment described above, the rotating electric machine 10 includes a stator 11, a rotor 12, a rotation axis 13, a first bearing 201, a second bearing 202, a bracket 30, a pressing member 40, a first member 50, and a second member 60. The rotor 12 is rotatably provided inside the stator 11. The rotation axis 13 is configured to be rotatable integrally with the rotor 12. The first bearing 201 and the second bearing 202 are provided at both end portions of the rotation axis 13 to rotatably support the rotation axis 13.

[0037] Among the brackets 30, the second bracket 302 has a rotation shaft 13 passed therethrough inside, and holds the second bearing 202 movably in the axial direction of the rotation shaft 13. Further, the second bracket 302 has a female screw portion 33 inside, the screwing direction of which is the axial direction of the rotation shaft 13. The pressing member 40 elastically presses the first bearing 201 toward the second bearing 202 side.

[0038] The first member 50 has a rotation shaft 13 passed therethrough inside, and is provided inside the bracket 30, in this case, inside the second bracket 302. The first member 50 has a male screw portion 53 meshing with the female screw portion 33, and moves in the axial direction of the rotation shaft 13 by rotating in the rotation direction of the rotation shaft 13. And the second member 60 is fixed to the first member 50 and removably fixed to the second bracket 302.

[0039] According to this, even in a state where the rotating electric machine 10 is assembled, by rotating the first member 50 and the second member 60, the position in the axial direction of the rotation shaft 13 can be adjusted. Therefore, according to the present embodiment, in order to adjust the position in the axial direction of the rotation shaft 13, it is not necessary to disassemble and reassemble the rotating electric machine 10, and as a result, the work related to the position adjustment of the rotation shaft 13 can be reduced. Further, since it is not necessary to disassemble and reassemble for the position adjustment of the rotation shaft 13, wear and damage of each component constituting the rotating electric machine 10 can be reduced, and as a result, the overall reliability of the rotating electric machine 10 can be improved.

[0040] Further, the second member 60 has a plurality of second through holes 62. The second through holes 62 are formed through the second member 60 and are through holes for passing the second bolts 72. The second bracket 302 has a plurality of female screw holes 34. The female screw holes 34 are female screw holes into which the second bolts 72 passed through the second through holes 62 from the outside of the second member 60 are screwed. And the plurality of second through holes 62 are arranged at equal intervals on a circumference centered on the axis O of the rotation shaft 13.

[0041] According to this, the operator can rotate the first member 50 and the second member 60 with reference to the second through holes 62 arranged at equal intervals. As a result, the operator can easily grasp the amount of rotation of the first member 50 and the second member 60, that is, the amount of movement of the rotating shaft 13. Consequently, fine position adjustment of the rotating shaft 13 becomes easier.

[0042] The number of female screw holes 34 provided in the second bracket 302 is set to be less than the number of second through holes 62 provided in the second member 60. According to this, since the operator does not need to screw the second bolts 72 through all of the second through holes 62 provided in the second member 60, the man-hours for removing the second member 60 from the second bracket 302 can be reduced. Also, according to this, the number of female screw holes 34, which are more laborious to machine than the second through holes 62, can be suppressed. As a result, the machining man-hours of the second bracket 302 can be reduced, and thus the manufacturing cost of the rotating electric machine 10 can be lowered.

[0043] Note that the above-described rotating electric machine 10 is premised on the rotating shaft 13 facing the horizontal direction, but the idea of the present embodiment can also be applied to a configuration in which the rotating shaft 13 faces the vertical direction, that is, the up-and-down direction, as shown in FIG. 6. In this case, the first bearing 201, the first bracket 301, and the pressing member 40 are preferably located above the rotating electric machine 10, and the second bearing 202, the second bracket 302, the first member 50, and the second member 60 are preferably located below the rotating electric machine 10. According to this, since the second bearing 202 is pressed against the first member 50 by the weight of the rotating shaft 13, the elastic force of the pressing member 40 can be made small.

[0044] Also, in this case, as shown in FIG. 6, it is preferable that the second bolt 72 is screwed into the side surface of the large-diameter portion 31 of the second bracket 302. According to this, when attaching and detaching the second bolt 72, the work can be performed from the side of the rotating electric machine 10, so there is no need to look into the lower side of the rotating electric machine 10 to perform the work, and the workability is improved.

[0045] Although the present disclosure has been described in accordance with the embodiments, it is understood that the present disclosure is not limited to these embodiments or structures. The present disclosure also includes various modifications and variations within the equivalent scope. In addition, various combinations and forms, as well as other combinations and forms including only one element, more than one element, or less than one element thereof, are within the scope and spirit of the present disclosure.

Description of Reference Numerals

[0046] 10... rotating electrical machine, 11... stator, 12... rotor, 13... rotating shaft, 20... bearing, 201... first bearing, 202... second bearing, 30... bracket, 301... first bracket, 302... second bracket, 33... female screw portion, 34... female screw hole, 40... pressing member, 50... first member, 53... male screw portion, 60... second member, 62... second through hole, through hole, 72... second bolt, bolt

Claims

1. A stator; a rotor rotatably provided inside the stator; a rotating shaft rotatable integrally with the rotor; a first bearing and a second bearing provided at both end portions of the rotating shaft to rotatably support the rotating shaft; a bracket having a female screw portion with an inner screw-in direction along the axial direction of the rotating shaft, through which the rotating shaft passes inside to movably hold the second bearing in the axial direction of the rotating shaft; a pressing member that elastically presses the first bearing toward the second bearing; a first member provided inside with the rotating shaft passing therethrough and provided inside the bracket, having a male screw portion meshing with the female screw portion, and moving in the axial direction of the rotating shaft by rotating in the rotation direction of the rotating shaft; a second member fixed to the first member and removably fixed to the bracket; A rotating electrical machine comprising the above components.

2. The second member has a plurality of through holes formed therethrough for passing bolts; The bracket has a plurality of female screw holes into which the bolts passed through the through holes from the outside of the second member are screwed; The plurality of through holes are arranged at equal intervals on a circumference centered on the axis of the rotating shaft. The rotating electrical machine according to Claim 1.

3. The number of the female screw holes provided in the bracket is set to be less than the number of the through holes provided in the second member. The rotating electrical machine according to Claim 2.

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