JP2001069720A - Structure for positioning rotor in axial direction in dynamo-electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to easily match the positions in the axial direction of the rotating side and fixing side of a rotation detector by mounting the rotation detector of a dynamo-electric machine at the position close to the bearing side for determining the axial dissection of the rotor with respect to the stator. SOLUTION: In a dynamo-electric machine 1 in which a rotor 2 is supported on the output shaft side end bracket 5 of a fixing side and an opposite output shaft side end bracket 6 in such a way as to be rotatable via an output shaft side bearing 3 and an opposite output shaft side bearing 4, a rotation detector 10 is mounted at the opposite output shaft side end of the rotor 2. The positioning of the rotor 2 to a stator 8 in the axial direction is performed by tightening a bearing fixing plate 11 provided in the bearing string part of the opposite output shaft side end bracket 6 with a bolt 12. This reduces an effect by the accumulated tolerance of the assembly of each component of the dynamo-electric machine 1 and the difference in the elongation by thermal expansion on the relation of the mounting position in the axial direction of a rotating plate 14 to a module plate 15 in the rotation detector 10, thereby making it easy to match the position in the axial direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotating electric machine in which the rotor is axially fixed to a stator, and more particularly to a rotating electric machine having a rotation detector.

[0002]

2. Description of the Related Art A conventional invention is disclosed in Japanese Unexamined Patent Publication No. 7-245917.
As described in the publication, an opening provided such that a shaft center provided in a jacket of the rotating electric machine is in a radial direction of the rotating electric machine was provided, and a fixing portion of a rotation position detector was inserted into this opening and attached to the shaft. A rotational position detector, wherein the rotational position detector is provided with an external connection lead wire or an electrical connector provided outside the fixed part, and fixed means for fixing the fixed part from the outside to the opening. It was a servo motor.

[0003]

The above prior art describes a structure in which a fixed portion of a rotation detector is mounted from a radial direction of a rotating electric machine, and an axial position between a rotation side and a fixed side of the rotation detector is described. There is no clear description of the alignment, and there is a problem with the axial alignment with the rotating side when the fixed side of the rotation detector is mounted from the radial direction.

[0004] It is an object of the present invention to provide a structure that facilitates axial alignment of a rotation side and a fixed side of a rotation detector attached to a rotating electric machine.

Another object is to prevent a relative displacement of the rotor with respect to the stator in the axial direction even when an axial load is input from the output shaft end of the rotating electric machine, thereby preventing damage to the rotation detector. The purpose of the present invention is to make it easy to obtain a structure that performs

[0006]

In order to achieve the above object, an axial position where a rotation detector of a rotating electrical machine is mounted is provided at a position close to a bearing on which a rotor is axially positioned and fixed relative to a stator. It was made.

In order to achieve another object, the position of the bearing for axially positioning and fixing the rotor with respect to the stator is set as a non-output shaft side bearing.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIG.

FIG. 1 is a sectional view of a rotating electric machine 1 according to one embodiment of the present invention. The rotor 2 is rotatably supported by the fixed output shaft side end bracket 5 and the non-output shaft side end bracket 6 via the output shaft side bearing 3 and the non-output shaft side bearing 4. The end brackets 5 and 6 are connected to the stator frame 7 to form a box that can accommodate the bearings 3 and 4. The stator 8 has a stator 8
Is held.

The end of the shaft 9 of the rotor 2 for taking out the driving force generated by the rotating electric machine 1 is processed with an involute spline so that the driving force can be taken out.

A rotation detector 10 for detecting the rotation of the rotating electric machine 1 is attached to the end of the rotor 2 on the side opposite to the output shaft.

The axial positioning of the bearings 3 and 4 attached to the rotor 2 is performed by abutting against a step provided on the shaft 9, and the coupling between the outer diameter of the shaft 9 and the inner diameter of the bearings 3 and 4 is performed. , Made by press fitting.

The positioning of the rotor 2 in the axial direction with respect to the stator 8 is performed by sandwiching the non-output shaft side bearing 4 with the bearing fixing plate 11 in a bearing storage box formed on the non-output shaft side end bracket 6. The structure is such that the output shaft side end bracket 6 and the bearing fixing plate 11 are tightened and fixed using bolts 12.

The box portion of the output shaft side end bracket 5 that houses the output shaft side bearing 3 is generated at the time of assembly due to the manufacturing dimensional tolerance of the fixed side component including the stator 8 and the rotating side component including the rotor 2. The gap 13 is provided to absorb the tolerance in the axial assembly and the thermal expansion and expansion between the rotating side and the fixed side.

The rotation detector 10 attached to the rotating electric machine 1 of the present embodiment is an optical encoder.
A rotating plate 14 having a plurality of slits cut at equal pitches in the circumferential direction is attached to the rotating side of the rotating shaft 0 so as to rotate integrally with the shaft 9, and a fixed side on which a photocoupler is arranged so as to sandwich the rotating plate 14. Is mounted on the non-output side end bracket 6. As a result, when the rotor 2 rotates, the rotating plate 14 rotates, and the light of the photocoupler built in the module 15 is transmitted to the rotating plate 1.
The rotation direction and the rotation speed of the rotor 2 can be detected by blocking or passing the slit formed in the rotor 4.

The axial position of the rotary plate 14 of the rotation detector 10 and the module 15 in the axial direction must be such that the rotary plate 14 is located at the center between narrow photocouplers formed on the module 15.

In the structure shown in FIG. 1, the reference for assembling the stationary component including the stator 8 and the rotating component including the rotor 2 in the axial direction is based on the non-output bearing 4, and the rotation detector 10 Since it is mounted at an axial position very close to the anti-output bearing 4 which is an axial assembly reference, the difference in elongation due to integration of tolerance of assembly of each component of the rotary electric machine 1 and expansion due to thermal expansion is determined by the rotation plate 14 in the rotation detector 10. Module 15 of
, The influence on the axial mounting position relationship can be reduced.

Thus, the rotating plate 14 can be positioned at the center of the gap between the narrow photocouplers formed in the module 15 of the rotation detector 10 only by assembling the components.

FIG. 2 shows a case where the rotor 2 is axially positioned and fixed with respect to the stator 8 from the bearing 4 on the side opposite to the output shaft to the bearing 3 on the output shaft in FIG. FIG. 3 is a diagram showing a case where the rotor is configured to be positioned on a side opposite to an output shaft-side bearing that is opposite to a bearing that is axially positioned and fixed relative to a stator of the rotor in the rotary electric machine;

In this structure, the reference of the axial assembly of the fixed component including the stator 8 and the rotating component including the rotor 2 is based on the output shaft bearing 3, and the absorption and heat absorption of the axial assembly integration tolerance. A gap 13 for absorbing the differential expansion and elongation is set on the side of the bearing 4 opposite to the output shaft. In this case, since the rotation detector 10 is located at a portion that absorbs the accumulation of the axial assembly tolerance and the thermal expansion difference,
Greatly affects the axial positional relationship with respect to the module 15. As a result, the rotating plate 14 is connected to the module 1
5 may not be able to be located between the narrow photocouplers formed.

On the other hand, FIG. 3 shows a case where the reduction gear 16 is connected to the rotating electric machine 1 in FIG.

In order to take out the driving force generated by the rotating electric machine 1, the tip of the shaft 9 is subjected to involute spline processing, and is used in combination with the shaft 17 of the speed reducer 16. When the rotating electric machine 1 and the speed reducer 16 are coupled, if an inclination occurs between the two, axial loads 18 and 19 are generated on both shafts due to contact friction of the spline portions. In this case, since the rotor 2 is axially positioned and fixed by the output shaft side bearing 3, the axial load 18 is
When the fitting force due to the press fitting of the outer diameter and the inner diameter of the output shaft side bearing 3 is exceeded, a gap 13 for absorbing the difference in the axial assembly integration tolerance set in the portion of the non-output side bearing 4 and the difference in thermal expansion and elongation. The rotor 2 moves in the axial direction. As a result, the rotating plate 1 of the rotation detector 10
4 moves in the axial direction and comes into contact with the module 15, thereby damaging the rotation detector 10.

In order to prevent the rotor 2 from moving in the axial direction even when an axial load 18 is applied in the structure shown in FIG. 2, the shaft 9 of the output shaft side bearing 3 is attached to the shaft 9 as shown in FIG. After machining the directional retaining groove 20 and press-fitting the bearing 4 into the shaft 9, it becomes necessary to incorporate the C-ring 21 to prevent the bearing from falling off. In this structure, costs such as groove processing and C-ring component cost are generated, and there is a concern that the shaft 9 may be damaged by stress concentration due to the groove processing.

Therefore, as shown in FIG.
, The rotation plate 14 of the rotation detector 10 and the module 15 can be easily aligned in the axial direction, and even when an axial load 18 is generated, the load is applied to the opposite side of the output shaft. Since it can be received by the bearing 4, the risk of damage to the shaft 9 is increased at low cost, the axial movement of the rotor 2 can be prevented, and the damage of the rotation detector 10 can also be prevented.

Further, the structure of the present invention can be applied not only when the speed reducer 16 is connected but also when the driving force transmission between the shaft 9 and the speed reducer shaft 17 is connected by a helical gear.
This is also effective in a structure in which the axial load 18 is constantly applied to the shaft 9 by the component of the torsion angle of the gear.

[0026]

Since the present invention is constructed as described above, it is easy to axially align the rotation side and the fixed side of the rotation detector attached to the rotating electric machine. Also, even if an axial load is input from the output shaft side of the rotating electric machine, the rotor can be prevented from moving in the axial direction without machining and components for stopping the axial movement, preventing damage to the rotation detector. Has the effect of doing

[Brief description of the drawings]

FIG. 1 is a sectional view of a rotating electric machine according to an embodiment of the present invention.

FIG. 2 is a view showing an output-side bearing for axial positioning.

FIG. 3 is a diagram showing a case where a reduction gear is combined with an output-side bearing for axial positioning.

FIG. 4 is a sectional view when a C-ring is used for fixing the rotor in the axial direction.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Rotating electric machine, 2 ... Rotor, 3 ... Output shaft side bearing, 4 ... Non-output shaft side bearing, 5 ... Output shaft side end bracket, 6 ... Non-output shaft side end bracket, 7 ... Stator frame, 8
... stator, 9 ... shaft, 10 ... rotation detector, 11 ... bearing fixing plate, 12 ... bolt, 13 ... clearance, 14 ... rotating plate, 15 ... module, 16 ... reduction gear, 17 ... reduction gear shaft, 18 ... Axial load input to the rotating electric machine, 19 ...
Axial load to be input to the reduction gear, 20 ... axial direction retaining groove, 21 ... C-ring.

Claims (3)

[Claims] 1. A rotating electric machine having a plurality of bearings mounted on a rotor and having a detector for detecting a rotational speed or the like mounted thereon, wherein the axial positioning and fixing of the rotor with respect to the stator are close to the detector mounting position. A rotating electric machine characterized by being a bearing on the side. 2. A rotating electric machine having a plurality of bearings mounted on a rotor and having a detector for detecting a rotational speed or the like mounted thereon, wherein the positioning of the rotor relative to the stator in the axial direction is fixed by an output shaft. A rotating electric machine characterized by a side bearing. 3. The rotating electric machine according to claim 2, wherein the output shaft is formed by a helical gear.