JP7117983B2 - Resolver - Google Patents

Description

The present invention includes a stator having windings formed by winding an electric wire around each of a plurality of magnetic pole teeth, and a rotor. It relates to a resolver that detects A plurality of magnetic pole teeth of the stator are arranged in an annular shape.

Patent Document 1 discloses a resolver that includes a rotor that includes a magnetic portion and is rotatably attached to a casing, and an annular stator that includes a plurality of magnetic pole teeth wound with windings and is fixed to the casing. It is

JP-A-10-146033

A rotor portion of a conventional resolver is composed of an input shaft press-fitted into an inner ring of a bearing, and a rotor core made of a magnetic material and fixed to the input shaft. Also, the stator portion is composed of a housing to which the outer ring of the bearing is fixed, and a stator fixed to the housing. Further, the stator has a plurality of magnetic pole teeth on which windings are wound on the inner circumference, and the stator core is made of an annular silicon steel plate. Generally, as the material of the housing, an aluminum alloy is used, which can be shaped by die-casting at low cost and is light in weight.

However, if the stator core made of silicon steel is fixed to the housing made of aluminum alloy, which has a coefficient of thermal expansion nearly twice that of the silicon steel plate, the stator core receives stress due to the difference in thermal expansion from the housing made of aluminum alloy when the temperature changes. , may be deformed into an distorted shape. As a result, the magnetic properties of the stressed portion change, degrading the detection accuracy of the resolver. As described above, there is a problem that the shape of the stator core changes due to the temperature change, and the detection accuracy of the resolver deteriorates.

SUMMARY OF THE INVENTION It is an object of the present invention to reduce deterioration of resolver detection accuracy due to temperature changes.

A resolver according to the present invention includes a housing, a rotor that is rotatably mounted inside the housing and has a magnetic body, and is arranged inside the housing on the outer circumference of the rotor and has a plurality of magnetic pole teeth on the inner circumference. A resolver including an annular stator core and a stator provided with windings wound around the magnetic pole teeth, wherein a resin insulator is integrally formed on one surface of the stator core, The stator is fixed to the stator holding member so that the surface on which the insulator is formed contacts the stator holding member, and is fixed to the housing via the stator holding member so as to be separated from the housing. ,

In this way, the stator is spaced apart from the housing, which has a large coefficient of thermal expansion, so that deformation of the housing does not directly affect the stator. can.

In one aspect of the resolver of the present invention, the stator holding member may be made of a material having higher rigidity than the stator core and substantially the same coefficient of thermal expansion as the stator core.

According to this aspect, when the temperature changes, the stress due to the difference in thermal expansion between the stator core and the housing is received by the stator holding member, which has higher rigidity than the stator core. Deformation of the stator core can be suppressed. Further, since the stator holding member has a coefficient of thermal expansion substantially equal to that of the stator core, there is almost no difference in thermal expansion between the stator core and the stator holding member when the temperature changes, and the stator core receives little thermal stress. Therefore, it is possible to suppress the deformation of the stator core due to the temperature change, and reduce the deterioration of the detection accuracy of the resolver.

In one aspect of the resolver of the present invention, the stator is arranged axially between the housing and the stator holding member, and the stator holding member is made of a material having a magnetic permeability equal to or higher than that of steel. may have been

According to this aspect, the magnetic flux entering the stator from the outside can be guided to the stator holding member, and a shield effect can be obtained that suppresses changes in the magnetic properties of the stator due to the external magnetic flux. Therefore, it is possible to reduce the deterioration of the detection accuracy of the resolver due to the external magnetic flux.

The present invention can suppress the deformation of the stator core due to temperature changes and reduce the deterioration of the detection accuracy of the resolver as compared with the case where the stator is directly fixed to the housing.

It is a sectional view showing a resolver which is one embodiment of the present invention. FIG. 2 is a top plan view of a part of the rotor and stator of the resolver shown in FIG. 1; 5 is a cross-sectional view showing a resolver of Comparative Example 1; FIG.

A resolver 1 according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view showing a resolver 1 according to an embodiment of the invention. FIG. 2 is a top view of part of the rotor 2 and stator 3 of the resolver 1 shown in FIG.

As shown in FIG. 1, the input shaft 21 of the resolver 1 is press-fitted into an inner ring of a bearing 22 and rotatably attached to the housing 4 via the bearing 22 . A disk-shaped rotor 2 made of a magnetic material is fixed to the input shaft 21 . That is, the rotor 2 is rotatably mounted inside the housing 4 via the input shaft 21 and the bearing 22 . As shown in FIG. 2, the outer peripheral portion of the rotor 2 has an uneven shape.

As shown in FIG. 1, the housing 4 has an annular shape with a hole for bonding and fixing the outer ring of the bearing 22, and is die-cast from an aluminum alloy having a coefficient of thermal expansion nearly twice that of a silicon steel plate. Manufactured by molding. The outer ring of bearing 22 is adhesively fixed to housing 4 .

As shown in FIGS. 1 and 2, the annular stator 3 is arranged axially on the outer periphery of the rotor 2 inside the housing 4 between the housing 4 and a sheet metal 41 that is a stator holding member. The stator core 31 is made of a silicon steel plate and has a plurality of magnetic pole teeth on its inner periphery. A resin insulator 32 is formed on one surface of the magnetic pole tooth portion and the stator core 31 by integral molding by injection molding. Furthermore, a winding 33 is wound around the portion of the magnetic pole tooth covered with an insulator 32 made of resin. The stator 3 is fixed to a disk-shaped sheet metal 41 with stator fixing bolts 34 so that the surface side on which the resin insulator 32 is formed contacts the sheet metal 41 . The resin insulator 32 also functions as a spacer to prevent the winding 33 from coming into contact with the metal plate 41 .

The winding 33 is connected to a position detection circuit (not shown) and is excited by alternating current. The rotational position of the input shaft 21 can be detected by detecting the change in reluctance between the rotor 2 and the stator 3 due to the rotation of the rotor 2 from the inter-winding voltage.

The sheet metal 41 is manufactured by punching a plate material made of steel, and has higher rigidity than the stator core 31 . As shown in FIG. 1 , the sheet metal 41 has an outer diameter larger than that of the stator 3 and covers the stator 3 from above. It is conceivable that the sheet metal 41 is not disc-shaped but has a ring shape with a hole formed in the center. The stator 3 is covered above.

The stator 3 is fixed to the metal plate 41 by the stator fixing bolts 34 in a state where the stator 3 is not in contact with the housing 4 and is separated from the housing 4 . The sheet metal 41 is fixed to the housing 4 with a sheet metal fixing bolt 42 . Therefore, the stator 3 is fixed to the housing 4 via the metal plate 41 while being separated from the housing 4 .

As described above, the stator 3 is separated from the housing 4 made of aluminum alloy having a large coefficient of thermal expansion, and the deformation of the housing 4 does not directly affect the stator 3. Therefore, the deformation of the stator core 31 due to the temperature change is suppressed, and the resolver 1 can be reduced.

In addition, when the temperature changes, the stress due to the difference in thermal expansion between the stator core 31 and the housing 4 is applied to the sheet metal 41 having higher rigidity than the stator core 31 . Deformation of the stator core 31 can be suppressed. Furthermore, since the sheet metal 41 is made of steel having a coefficient of thermal expansion substantially equal to that of the stator core 31 made of silicon steel, there is almost no difference in thermal expansion between the stator core 31 and the sheet metal 41 when the temperature changes, and the stator 3 receives the heat. Low thermal stress. Therefore, in the resolver 1 of the present embodiment, deformation of the stator core 31 due to temperature change is suppressed more than in the case where the stator 13 is directly fixed to the housing 14 like the resolver 10 of Comparative Example 1, which will be described later. Accuracy deterioration can be reduced.

In addition, since the material of the sheet metal 41 is steel, which is a magnetic material with high magnetic permeability, the magnetic flux entering the stator 3 from the outside can be guided to the sheet metal 41, and changes in the magnetic characteristics of the stator 3 due to the external magnetic flux can be suppressed. You get the effect of a suppressing shield. Therefore, it is possible to reduce the deterioration of the detection accuracy of the resolver 1 due to the external magnetic flux.

Further, the sheet metal 41 made of steel is mass-produced and available at low cost, and can be shaped by press working or the like at low cost. Therefore, it is possible to provide the resolver 1 with high precision and low cost.

If the resin insulator 32 is not used as a spacer and the sheet metal 41 is provided with a hole or a bend by press working or the like so that the windings 33 do not interfere with the sheet metal 41 , the stator 3 and the sheet metal 41 are in direct contact. As a result, the magnetic flux leaking to the sheet metal 41 side increases and has an adverse effect. In order to prevent this, a material such as non-magnetic austenitic stainless steel is suitable for the sheet metal 41. In comparison, the austenitic stainless steel material has the disadvantage that the difference in thermal expansion from that of the silicon steel sheet is somewhat large.

Here, a resolver 10 of Comparative Example 1 for comparison with the resolver 1 of this embodiment will be described. In the resolver 10 of Comparative Example 1 shown in FIG. 3, the same components as those of the resolver 1 of the present embodiment are denoted by the same reference numerals, and descriptions thereof are omitted.

In the resolver 10 of Comparative Example 1, the stator 13 and the cover 5 are fixed to the housing 14 by stator fixing bolts 134 . The annular stator core 131 is made of a silicon steel plate, and the housing 14 is manufactured by die-casting an aluminum alloy.

Therefore, the stator core 131 made of a silicon steel plate is directly fixed to the housing 14 made of an aluminum alloy whose coefficient of thermal expansion is nearly twice that of the silicon steel plate. It may be deformed into a distorted shape due to stress caused by When the stator core 131 deforms into an distorted shape in this manner, the magnetic characteristics of the stressed portion change, and the detection accuracy of the resolver 10 deteriorates.

In contrast, in the resolver 1 of the embodiment, the sheet metal 41 receives stress due to the difference in thermal expansion between the stator core 31 and the housing 4 when the temperature changes. can be reduced.

1, 10 resolver, 2 rotor, 3, 13 stator, 4, 14 housing, 5 cover, 21 input shaft, 22 bearing, 31, 131 stator core, 32 insulator, 33 winding, 34, 134 stator fixing bolt, 41 sheet metal ( stator holding member), 42 sheet metal fixing bolt.

Claims (3)

a housing;
a rotor rotatably mounted inside the housing and provided with a magnetic body;
A resolver that includes a stator that is arranged on the outer periphery of the rotor inside the housing and includes an annular stator core provided with a plurality of magnetic pole teeth on the inner circumference and a winding wound around the magnetic pole teeth,
A resin insulator is integrally formed on one surface of the stator core,
The stator is fixed to the stator holding member so that the surface on which the insulator is formed contacts the stator holding member, and is fixed to the housing via the stator holding member so as to be separated from the housing. ,
A resolver characterized by A resolver according to claim 1,
The stator holding member is made of a material having higher rigidity than the stator core and substantially the same coefficient of thermal expansion as the stator core;
A resolver characterized by The resolver according to claim 1 or 2,
The stator is arranged axially between the housing and the stator holding member, and the stator holding member is made of a material having a magnetic permeability equal to or higher than that of steel;
A resolver characterized by

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