JP2022157815A - Resolver integrated type bearing device - Google Patents

Abstract

To provide a resolver integrated type bearing device which suppresses eccentricity of a stator, and thereby improves detection accuracy.SOLUTION: A stator holder 40 is made of a synthetic resin, is fixed to an inner peripheral surface of an outer ring 21, and is fit to an outer peripheral surface 34c of a stator core 34.SELECTED DRAWING: Figure 1

Description

The present invention relates to a resolver-integrated bearing device having a resolver capable of detecting the rotation angle of a rotating shaft.

In Patent Document 1, a stator provided with a plurality of projections on the outer periphery is press-fitted and fixed to a case member formed by press working, and the case member is bolted to a housing to receive the influence of distortion of the case member. A resolver is disclosed in which the stator can be attached without Further, in Patent Document 2, a stator is press-fitted to the inner peripheral surface of the outer ring of a rolling bearing, and an eccentric cylindrical rotor is provided at a position facing the stator on the outer peripheral surface of the inner ring. A rolling bearing unit is disclosed.

Japanese Patent No. 5870607 Japanese Patent No. 4238576

However, according to the resolver described in Patent Literature 1, the stator is press-fitted and fixed to the case member made of a plate material that is thin enough to be pressed, so the case member may be deformed and the stator may become eccentric. . For this reason, the possibility that the detection accuracy is lowered cannot be ruled out, and there is room for improvement. Further, according to the sensor-equipped rolling bearing unit disclosed in Patent Document 2, the stator is press-fitted into the inner peripheral surface of the outer ring. was there.

SUMMARY OF THE INVENTION The present invention has been made in view of the problems described above, and an object of the present invention is to provide a resolver-integrated bearing device that improves detection accuracy by suppressing eccentricity of the stator.

The above objects of the present invention are achieved by the following configurations.
[1] a bearing that rotatably supports a rotating shaft with respect to a housing;
a rotor attached to the rotating shaft;
a stator disposed radially outward of the rotor with a gap therebetween;
a stator holder that is attached to the outer ring of the bearing and holds the stator core of the stator;
A resolver-integrated bearing device comprising:
The resolver-integrated bearing device, wherein the stator holder is made of synthetic resin, is fixed to the inner peripheral surface of the outer ring, and is fitted to the outer peripheral surface of the stator core.

According to the resolver integrated bearing device of the present invention, the eccentricity of the stator can be suppressed by the synthetic resin stator holder, and detection accuracy can be improved.

FIG. 4 is a cross-sectional view of the resolver-integrated bearing device according to one embodiment of the present invention, and is a cross-sectional view taken along the line II of FIG. 3; FIG. 2 is a view of the resolver-integrated bearing device shown in FIG. 1 as viewed from arrow II. FIG. 2 is a view of the resolver-integrated bearing device shown in FIG. 1 as viewed from arrow III. 1 is an exploded perspective view of a resolver-integrated bearing device; FIG.

An embodiment of a resolver-integrated bearing device according to the present invention will be described in detail below with reference to the drawings.
As shown in FIGS. 1 to 4, the resolver-integrated bearing device 10 of this embodiment includes a rolling bearing 20 that rotatably supports a rotating shaft 11 with respect to a housing 50, and a motor used in, for example, a hybrid vehicle. and a resolver 30 that detects the rotational speed of the rotating shaft 11 of the generator.

The rolling bearing 20 is fitted to an inner peripheral surface 51 of a cylindrical housing 50, and is fitted to an outer ring 21 having an outer ring raceway 21a formed on its inner peripheral surface, and to an outer peripheral surface of the rotating shaft 11, having an inner ring formed on its outer peripheral surface. An inner ring 22 having a raceway 22a formed thereon, and a plurality of rollers disposed between the outer ring raceway 21a and the inner ring raceway 22a and held rollably by a retainer 24 (in this embodiment, a crown-shaped retainer made of resin). and a ball 23 which is a rolling element.
Note that the rolling bearing 20 is not limited to a ball bearing, and may be another type of rolling bearing.

The resolver 30 includes a rotor 31 that is fixed to the rotating shaft 11 and rotates together with the rotating shaft 11, and a stator 32 that is arranged radially outwardly of the rotor 31 with a radial gap C interposed therebetween. The rotor 31 has a non-circular shape with different outer diameters along the circumference so that the radial clearance C with the stator 32 changes with rotation.
Therefore, when the rotary shaft 11 rotates, the rotor 31 rotates integrally, the gap between each tooth 33 of the stator 32 and the rotor 31 changes, and a voltage corresponding to the rotation angle of the rotor 31 is applied to the coil 36 of the stator 32 . can get.

The stator 32 is formed by laminating a plurality of substantially annular silicon steel plates, a stator core 34 provided with a plurality of teeth 33 protruding radially inward on the inner peripheral surface, and an insulator on each tooth 33 of the stator core 34 . Each coil 36 is wound through 35 . The insulator 35 is made of an insulating material such as synthetic resin and insulates the teeth 33 and the coil 36 from each other.
Note that the front side of the coil 36 (the right side in FIG. 1) may be covered with an annular plate-shaped cover 39 as in the present embodiment.

A substantially rectangular box-shaped terminal block 37 is attached to the outer peripheral surface of the stator core 34 so as to protrude radially outward. is derived to the outside through

Stator core 34 is fixed to stator holder 40 . The stator holder 40 is made of synthetic resin. 44, and an annular portion 43 extending from an outer peripheral portion on one axial side (right side in FIG. 1) of the annular plate portion 42 to one axial side.

The annular convex portion 44 is press-fitted into an annular concave portion 21 b formed in the inner peripheral surface of the outer ring 21 by notching a shoulder portion of the outer ring 21 to fix the stator holder 40 integrally with the outer ring 21 . Thereby, the stator core 34 of the stator 32 is integrally attached to the rolling bearing 20 via the stator holder 40 .

Therefore, in the present embodiment, the annular recess 21b is formed on the opposite side of the ball 23 from the annular portion of the crown retainer 24 in the axial direction. That is, the resolver 30 is arranged on the pocket opening side of the crown-shaped retainer 24 made of resin via the stator holder 40 .
Here, if an iron retainer is used as the retainer, magnetic flux may be disturbed if the iron retainer, which is a magnetic material, is close to the resolver 30 , which may affect the detection accuracy of the resolver 30 . In that case, it is necessary to increase the bearing width and separate the resolver 30 from the iron retainer, which may increase the size and cost. Therefore, by arranging the resolver 30 on the pocket opening side of the crown-shaped retainer 24 made of resin as in the present embodiment, the above problem can be solved.

In the stator holder 40, a stator storage portion 41 having a substantially L-shaped cross section is formed by a side surface 42a on one axial side of the annular plate portion 42 and an inner peripheral surface 43a of the annular portion 43 to accommodate the stator core 34. It is When the stator core 34 is accommodated in the stator accommodation portion 41 , the outer peripheral surface 34 c of the stator core 34 is fitted to the inner peripheral surface 43 a , and the side surface 34 b on the other axial side of the stator core 34 is aligned with the side surface of the annular plate portion 42 . 42a.

The stator holder 40 is made of synthetic resin and has a coefficient of linear expansion equivalent to that of the stator core 34 . As a result, even if the temperature of the resolver 30 changes, the fitting state of the stator core 34 and the stator holder 40 is less changed, and the eccentricity of the stator core 34 is suppressed to maintain good detection accuracy. Further, if the stator holder 40 is formed by injection molding, other parts attached to the stator holder 40 can be molded at the same time, and the number of parts can be reduced.

The stator core 34 is fitted in the stator housing portion 41 with a clearance fit, centered with respect to the rotor 31 , and then fixed to the stator holder 40 with a plurality of rivets 52 . The rivet 52 is inserted through a rivet hole 34a provided on the outer peripheral side of the stator core 34 and a rivet hole 42b axially penetrating the annular plate portion 42 from a side surface 42a on one axial side of the annular plate portion 42. The stator core 34 is fixed to the stator holder 40 by crimping from both sides.

In both side surfaces of the stator holder 40, radial grooves 47 are provided radially outward corresponding to the rivet holes 42b, and the crimped rivets 52 head portions 52a are aligned with both side surfaces of the stator holder 40. are configured so that they do not protrude from the

In this way, by fitting the stator core 34 into the stator storage portion 41 with a clearance fit and riveting the stator core 34 in a centered state with respect to the rotor 31 , radial stress can be applied from the stator holder 40 to the stator core 34 . Therefore, a decrease in accuracy due to the eccentricity of the stator core 34 is prevented.

If there is concern that the use of the metal rivets 52 may affect the magnetic flux, the rivets 52 are placed between the coils 36 to reduce the influence on the magnetic flux.
Furthermore, by setting the number of rivet holes 34a into which the rivets 52 are inserted to be 1/N (N: integer) of the number of coils 36, the magnetic flux can be uniformly affected, which is preferable. Note that the number of rivet holes 34 a is greater than the number of rivets 52 in this embodiment. Also, the number of rivet holes 34a is calculated assuming that they are arranged at equal intervals in the circumferential direction without considering the area of the terminal block 37. FIG.

The fixing of the stator core 34 and the stator holder 40 is not limited to the rivets 52, but may be by adhesion or press-fitting. When the stator core 34 is fixed to the stator housing portion 41 by adhesion, the stator core 34 and the stator housing portion 41 are fitted with a clearance fit and adhered to the rotor 31 in a centered state in the same manner as the fixing by the rivets 52 . Therefore, no radial stress is applied from the stator holder 40 to the stator core 34, and a decrease in accuracy due to eccentricity of the stator core 34 is prevented.

In the case of press-fitting, the stator core 34 is press-fitted into the stator housing portion 41, but by making the stator holder 40 made of resin, the radial thickness of the ring portion 43 can be easily increased. For this reason, compared with a thin plate case member formed by conventional press working, the annular portion 43 is less likely to deform, and eccentricity of the stator core 34 due to deformation of the annular portion 43 can be prevented. Therefore, a decrease in accuracy due to the eccentricity of the stator core 34 is prevented.

For example, in the present embodiment, the annular portion 43 has an outer peripheral surface that closely faces the inner peripheral surface 51 of the housing 50, and an inner peripheral surface 43a that is located on the inner diameter side of the outer peripheral surface of the annular convex portion 44. The radial thickness of the ring portion 43 is formed thick.

In addition, since the stator holder 40 is configured to abut against the axial side surface 34b of the stator core 34, the axial distance between the stator core 34 and the rolling bearing 20, which is required for a case member formed by press working, is reduced. Parts such as shims for securing are unnecessary, and the number of parts can be reduced.

A part of the stator holder 40 in the circumferential direction is notched to form an open groove 45 which is open to the stator 32 side and has a substantially U-shaped cross section. The edge of the stator holder 40 forming the open groove 45 surrounds the side surfaces 37a and 37b of the terminal block 37 and the side surface 37c on the bearing 20 side. As a result, the terminal block 37 of the stator can be protruded radially outward, and the axial thickness of the stator 32 can be reduced to contribute to compactness and weight reduction.

A projection 46 projecting radially outward is formed on the edge of the stator holder 40 forming the open groove 45 .
Further, in a portion of the housing 50 in the circumferential direction, a U-shaped notch groove 53 is provided that penetrates in the radial direction and opens toward the rolling bearing 20 when viewed from above. The edges of the housing forming the cutout grooves 53 come into contact with the circumferential side surfaces of the projections 46 of the stator holder 40 , and the projections 46 of the stator holder 40 are engaged with the cutout grooves 53 of the housing 50 . Rotation of the stator holder 40 is prevented. Therefore, creep of the rolling bearing 20 fixed to the stator holder 40 can be prevented.

Note that when the outer ring 21 of the rolling bearing 20 rotates due to creep, the stator holder 40 and the stator core 34 fixed to the outer ring 21 also rotate. The rotation of the stator core 34 directly affects the detection accuracy of the detected angle and the control of the motor based on the detected angle. In extreme cases, there is a risk that the cables and connectors of the resolver-integrated bearing device 10 may be damaged.

However, in the resolver 10 of the present embodiment, the creep of the outer ring 21 can be prevented, and the rotation of the stator core 34 can be prevented, thereby preventing deterioration in detection accuracy. Moreover, it is not necessary to fix the stator holder 40 to the housing 50 with screws, which contributes to a reduction in the number of parts, a reduction in assembly man-hours, and a compact resolver-integrated bearing device 10 .

It should be noted that the present invention is not limited to the above-described embodiments, and can be modified, improved, etc. as appropriate.

As described above, this specification discloses the following matters.
(1) a bearing that rotatably supports the rotating shaft with respect to the housing;
a rotor attached to the rotating shaft;
a stator disposed radially outward of the rotor with a gap therebetween;
, wherein a stator core of the stator is integrally mounted with the bearing.
According to this configuration, it is possible to improve the handleability of the stator core of the stator.

(2) a stator holder that is attached to the outer ring of the bearing and holds the stator core of the stator;
, wherein the stator core of the stator is integrally attached to the bearing via the stator holder, the resolver-integrated bearing device according to (1).
According to this configuration, it is possible to improve the handleability of the stator core of the stator.

(3) The resolver-integrated bearing device according to (2), wherein the stator holder is made of synthetic resin, fixed to the inner peripheral surface of the outer ring, and fitted to the outer peripheral surface of the stator core.
According to this configuration, the stator holder made of synthetic resin can increase the radial thickness of the stator holder, so that the eccentricity of the stator can be suppressed and the detection accuracy can be improved.

(4) The resolver-integrated bearing device according to (3), wherein the stator holder is in contact with the axial side surface of the stator core.
With this configuration, there is no need to provide shims for positioning the stator, and the number of parts can be reduced.

(5) The stator core is inserted into a stator storage portion that stores the stator core of the stator holder, and is fixed to the stator holder by press-fitting, bonding, or riveting.
The resolver-integrated bearing device according to (3) or (4).
According to this configuration, the stator can be reliably fixed to the stator holder while suppressing eccentricity of the stator.

(6) the stator holder has a coefficient of linear expansion equivalent to that of the material of the stator core;
A resolver-integrated bearing device according to any one of (3) to (5).
According to this configuration, even if the temperature of the resolver changes, the positional relationship between the stator holder and the stator core does not change, and good detection accuracy can be maintained.

(7) A terminal block to which cables to be connected to the coils of the stator are connected is attached to the outer peripheral surface of the stator core,
The stator holder has an open groove surrounding the terminal block,
Resolver-integrated bearing device according to any one of (3) to (6) According to this configuration, the axial thickness of the stator including the terminal block can be reduced, contributing to size reduction and weight reduction.

(8) The resolver-integrated bearing device according to any one of (3) to (7), wherein the bearing has a resin retainer.
According to this configuration, the retainer does not affect the magnetic flux of the resolver, and there is no need to increase the size of the bearing device.

10 Resolver Integrated Bearing Device 11 Rotating Shaft 20 Bearing 21 Outer Ring 30 Resolver 31 Rotor 32 Stator 34 Stator Core 34b Stator Core Axial Side 34c Stator Core Outer Peripheral Surface 36 Coil 37 Terminal Block 40 Stator Holder 41 Stator Housing 44 Annular Projection 45 Open Groove 50 Housing 52 Rivet C Gap

Claims (8)

a bearing that rotatably supports the rotating shaft with respect to the housing;
a rotor attached to the rotating shaft;
a stator disposed radially outward of the rotor with a gap therebetween;
, wherein a stator core of the stator is integrally mounted with the bearing. a stator holder that is attached to the outer ring of the bearing and holds the stator core of the stator;
2. The resolver-integrated bearing device according to claim 1, further comprising: a stator core of said stator integrally attached to said bearing via said stator holder. 3. The resolver-integrated bearing device according to claim 2, wherein said stator holder is made of synthetic resin, is fixed to an inner peripheral surface of said outer ring, and is fitted to an outer peripheral surface of said stator core. 4. The resolver-integrated bearing device according to claim 3, wherein said stator holder contacts an axial side surface of said stator core. The stator core is inserted into a stator storage portion that stores the stator core of the stator holder, and is fixed to the stator holder by press-fitting, bonding, or riveting.
The resolver-integrated bearing device according to claim 3 or 4. The stator holder has a coefficient of linear expansion equivalent to that of the material of the stator core,
The resolver-integrated bearing device according to any one of claims 3 to 5. A terminal block to which cables connected to the coils of the stator are connected is attached to the outer peripheral surface of the stator core,
The stator holder has an open groove surrounding the terminal block,
The resolver-integrated bearing device according to any one of claims 3 to 6. The resolver-integrated bearing device according to any one of claims 3 to 7, wherein said bearing has a resin retainer.

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