JP6922760B2 - Resolver - Google Patents

Description

The present invention relates to a resolver used in a rotary electric machine.

In a rotary electric machine (motor / generator), the rotation position of the rotor may be detected by a resolver. The resolver has a resolver rotor attached to the rotor and a resolver stator fixedly arranged around the resolver rotor. A coil is provided in the resolver stator, and the rotational position of the resolver rotor is acquired by exciting and detecting the magnetic flux. In the resolver, the detection accuracy may be lowered due to the leakage flux from the rotating electric machine.

The following Patent Document 1 describes a resolver having a stopper portion for preventing the knock pin used for positioning the resolver stator from coming off. FIG. 5 is a diagram quoting FIG. 3 of Patent Document 1. However, for convenience of explanation, the reference numerals have been changed. FIG. 5 is a perspective view showing a state in which the resolver stator 102 of the resolver 100 is fixed to the motor case 120. The resolver stator 102 includes a stator core 104 in which electromagnetic steel sheets are laminated, and a stator coil is provided on the inner peripheral side thereof. The stator coil is covered with a resin cover 106. Further, the motor case 120 is provided with a stator boss 122 having a screw hole. The resolver stator 102 is attached to the motor case 120 by fastening the screwed bolt 110 that penetrates the elongated hole 108 of the stator core 104 to the screw hole. The electric motor case 120 is also provided with a knock pin boss 124 having a knock hole. One end of the knock pin 112 is inserted into the knock hole, and the knock pin 112 is engaged with an engaging groove 114 provided on the side surface of the stator core 104. The other end of the knock pin 112 is held in contact with or non-contact with the stopper portion 106a having a structure in which a part of the resin cover 106 protrudes to the outer peripheral side, so that the knock pin 112 is prevented from falling off. There is.

Patent Document 2 below describes that the effect of the leakage flux on the motor side is prevented by covering the resolver coil with a magnetic shield cover.

Japanese Unexamined Patent Publication No. 2015-023622 Japanese Unexamined Patent Publication No. 9-65617

When a magnetic shield cover as described in Patent Document 2 is used in a resolver as described in Patent Document 1, it interferes with a knock pin or a stopper.

An object of the present invention is to realize a structure for preventing interference between a knock pin for positioning a resolver stator or a stopper provided for preventing the knock pin from coming off and a magnetic shield cover attached to the resolver stator.

The resolver of the present invention includes a resolver rotor attached to a rotor shaft of a rotary electric machine and a cylindrical resolver stator arranged around the resolver rotor, and the resolver stator is once attached to a case of the rotary electric machine. The resolver stator is provided with an engaging structure that engages with the knock pin into which the is inserted, and a stopper that is arranged to face the other end of the knock pin that is engaged with the engaging structure to prevent the knock pin from coming off. A magnetic shield cover is provided on the axial end surface on the rotor side, and the magnetic shield cover is formed in the vicinity of the stopper portion so as to bypass the knock pin or the stopper portion to the outer peripheral side.

Since the magnetic shield cover can be installed after preventing interference with the knock pin or the stopper, it is possible to achieve both the ease of mounting the resolver using the knock pin and the magnetic shielding property of the resolver using the magnetic shield cover. It becomes.

It is a top view of the resolver stator which concerns on this embodiment. It is a top view of the magnetic shield cover which concerns on this embodiment. FIG. 5 is a cross-sectional view taken along the line AA in the vicinity of the knock pin including the resolver stator and the magnetic shield cover according to the present embodiment. It is sectional drawing of BB in the vicinity of a bolt including a resolver stator and a magnetic shield cover which concerns on this embodiment. It is a figure explaining the resolver which concerns on the prior art.

Hereinafter, embodiments will be described with reference to the drawings. In the description, specific embodiments are shown for ease of understanding, but these are examples of embodiments, and various other embodiments can be taken.

FIG. 1 is a top view of the resolver stator 10 of the resolver according to the present embodiment. The resolver stator 10 has a structure similar to that of the resolver stator 102 shown in FIG. That is, the resolver stator 10 includes a stator core 12 formed by laminating disk-shaped electromagnetic steel sheets to form a cylindrical shape. A plurality of resolver coils for excitation and detection are wound inside the stator core 12. The resolver coil is covered with a resin cover 14. Although the resin cover 14 is substantially cylindrical, it is provided with a terminal cover portion 14a projecting to the outer peripheral side to cover terminals for wiring and a stopper portion 14b projecting to the outer peripheral side to prevent the knock pin from coming off. There is. The stator core 12 is provided with six elongated holes 12a near the outer circumference. Further, on the outer circumference of the stator core 12, an engaging groove 12b with which a knock pin is engaged is provided near an intermediate position between any two elongated holes 12a.

In the resolver stator 10, the terminal cover portion 14a and the stop portion 14b are provided at an angle of about 120 degrees. This is different from the resolver stator 102 shown in FIG. 5 having an angle of about 90 degrees between the two. Further, in the resolver stator 10, a total of seven elongated holes 12a are provided at an angular interval of about 50 degrees, whereas in the resolver stator 102 shown in FIG. 5, a total of four elongated holes 12a are provided at an interval of about 90 degrees. It differs in that it is. However, the overall structure of the resolver stator 10 is substantially the same as that of the resolver stator 102 shown in FIG.

The resolver stator 10 detects the rotational position of the rotor shaft in the electric motor (motor) or generator (generator) of the rotary electric machine. Although not shown, a rotor is arranged coaxially with the resolver stator 10 on the inner peripheral side of the resolver stator 10, and a resolver rotor that rotates with the rotor is attached to the rotor. The resolver stator 10 is fixedly attached around the resolver rotor. Fixing is performed, for example, by fastening to a rotary electric machine case as shown in FIG.

FIG. 2 is a top view of the magnetic shield cover 20 of the resolver. The magnetic shield cover 20 is a member formed by punching a metal plate. The magnetic shield cover 20 is attached to the upper end surface of the resolver stator 10 on the outer peripheral side of the resin cover 14 of the resolver stator 10. The magnetic shield cover 20 has an annular portion 22 having an overall annular shape, but the vicinity of the magnetic shield cover 20 overlapping the terminal cover portion 14a is cut off over about 90 degrees so as to avoid interference with the terminal cover portion 14a. ing. Further, the magnetic shield cover 20 is a protruding portion 24 whose vicinity thereof protrudes outward from the circumferential direction so as to avoid interference with the stop portion 14b of the resolver stator 10. The protruding portion 24 can also be said to have a relief shape to the outer peripheral side that avoids interference with the stopping portion 14b. The magnetic shield cover 20 is provided with five round holes 26a, 26b, 26c, 26d, 26e and two elongated holes 28a, 28b for purposes such as fixing. It is not necessary to use all of these for fixing. For example, bolts are inserted into the three round holes 26a, 26c, and 26e, the elongated holes 12a of the stator core 12 are passed through, and then the bolts are fastened to the rotary electric case. And can be fixed.

In the magnetic shield cover 20, the shapes of the transition portions 24a and 24b that transition from the annular portion 22 to the protruding portion 24 are set asymmetrically. That is, the width of the member is relatively narrow at the transition portion 24a relatively close to the nearest round hole 26c, and the width of the member is wider at the transition portion 24b relatively far from the nearest round hole 26d than at the transition portion 24a. doing. This is because the required strength is small at the transition site 24a near the round hole 26c. Further, when a fastening member such as a bolt is inserted into the round hole 26c, the fastening member can be expected to exert a shielding effect, so that the viewpoint of narrowing the width of the member at the transition portion 24a is also considered.

3 and 4 are cross-sectional views showing the AA cross section and the BB cross section of FIGS. 1 and 2, respectively, in a state where the resolver stator 10 and the magnetic shield cover 20 are assembled. The same configuration will be given the same number, and the description will be omitted or simplified as appropriate.

FIG. 3 is a cross-sectional view taken along the line AA of the vicinity of the resolver stator 10 including the stop portion 14b of the resin cover 14. The resolver stator 10 is formed in the resin cover 14 so that the coil ends 16a and 16b of the resolver coil protrude to the upper end side and the lower end side of the stator core 12, respectively. Further, in the resin cover 14, a stopper portion 14b is formed on the upper end surface side of the stator core 12 at a distance from the upper end surface.

A metal knock pin 30 is engaged with the engaging groove 12b of the stator core 12. The lower end side of the knock pin 30 is press-fitted into the knock hole 42a in the knock pin boss 42 of the rotary electric machine case 40 arranged so as to be in contact with the lower end surface of the stator core 12. As a result, the stator core 12 can be appropriately positioned in the circumferential direction. Further, the upper end of the knock pin 30 protrudes from the upper end surface of the stator core 12 and faces the stop portion 14b with a slight gap. In a rotary electric machine, the knock pin 30 may come off from the knock hole 42a due to thermal expansion or vibration due to heating, but the knock pin 30 is prevented from coming off by restricting the movement of the other end with the stop portion 14b.

The protruding portion 24 of the magnetic shield cover 20 is located on the outer peripheral side so as to avoid interference with the knock pin 30 and the stopper portion 14b.

At the upper right of the magnetic shield cover 20, a rotary electric machine stator 50 arranged around the rotor of the rotary electric machine is located. The rotary electric machine stator 50 includes a rotary electric machine stator core 52 in which electromagnetic steel plates are laminated, and a coil is wound in a slot provided on the inner peripheral side of the rotary electric machine stator core 52. FIG. 3 shows a coil end 54 protruding from the lower end surface of the rotary electric machine stator core 52. In this rotary electric machine, the magnetic field generated by the coil of the rotary electric machine stator core 52 exerts a magnetic force on the rotor to rotate the rotor.

FIG. 4 is a cross-sectional view taken along the line BB including the round hole 26e of the magnetic shield cover 20. The resin cover 14 of the resolver stator 10 has no stop portion 14b in this cross section, and has a simple shape that covers the coil ends 16a and 16b of the resolver coil. A bolt 60 is inserted into the elongated hole 12a provided in the stator core 12 of the resolver stator 10 by gap fitting. This is so that the position of the stator core 12 can be adjusted.

The bolt 60 is inserted in the order of the magnetic shield cover 20, the non-magnetic member 70, and the stator core 12 when viewed from the upper end side, and finally is inserted into the boss hole 44a provided at the upper end of the stator boss 44 of the rotary electric machine case 40. Has been done. The bolt 60 is threaded on the tip side and is engaged with and fastened with the screw threaded in the boss hole 44a.

The magnetic shield cover 20 has an annular portion 22 in this cross section, and is arranged so as to cover the upper end side of the stator core 12 and the outer peripheral side of the resin cover 14. A non-magnetic member 70 is provided between the magnetic shield cover 20 and the stator core 12. As a result, the magnetic shield cover 20 does not come into contact with the stator core 12 and is arranged at a slight distance. Further, the magnetic shield cover 20 does not come into contact with the resin cover 14, and is arranged at a slight distance.

Also in the cross section of FIG. 4, the rotary electric machine stator 50 is located on the upper right of the magnetic shield cover 20. This is because the rotary electric machine stator 50 is formed in a cylindrical shape that surrounds the rotor.

Subsequently, the operation of the rotary electric machine will be described. The rotary electric machine is not particularly limited in terms of use or type, but here, the description will be made assuming a three-phase alternating current permanent magnet type rotary electric machine used as a drive source for an electric vehicle. In the electric vehicle, the rotary electric machine is housed in the rotary electric machine case 40 and mounted on a predetermined portion of the electric vehicle. Then, the three-phase AC power is supplied from the separately installed inverter.

In a permanent magnet type rotary electric machine, the rotor includes a shaft which is a rotating shaft and a rotor core attached to the shaft. The rotor core is formed by, for example, laminating electromagnetic steel sheets, and a permanent magnet is inserted into a magnet hole provided therein. The permanent magnets form a plurality of magnetic poles in the rotor core by being inserted in a predetermined position and in a predetermined direction according to the design. On the other hand, a cylindrical rotary electric machine stator 50 fixed to the rotary electric machine case is arranged around the rotor of the rotary electric machine. A plurality of coils are wound around the rotary electric machine stator core 52 of the rotary electric machine stator 50, and a rotating magnetic field (rotating magnetic field) is generated by flowing a three-phase alternating current. This rotating magnetic field exerts a magnetic force on the magnetic poles formed on the rotor core, so that the rotor rotates around the rotation axis. Then, torque is transmitted from the shaft to the wheels of the electric vehicle, and the electric vehicle travels.

A resolver rotor of the resolver is fixed to the shaft. A resolver stator 10 is arranged around the shaft and is fixed to the rotary electric machine case 40. In the resolver, the resolver coil for excitation provided in the resolver stator 10 generates a magnetic field and sends it to the resolver rotor. Then, the resolver coil for detection provided in the resolver stator 10 detects the magnetic field via the resolver rotor. Since the resolver rotor is formed in an isotropic shape, the rotation angle of the resolver rotor and the rotation angle of the rotor can be obtained by analyzing the detected magnetic flux.

In order to improve the detection accuracy of the rotation angle by the resolver, it is necessary to reduce the influence of the magnetic field noise (called leakage flux) generated from the rotary electric machine stator 50. In particular, the magnetic flux leaking from the vicinity of the coil end 54 shown in FIGS. 3 and 4 is considered to affect the stator core 12 or the coil ends 16a and 16b of the resolver stator 10. The magnetic shield cover 20 is provided to reduce the influence of the leakage flux.

When the metal magnetic shield cover 20 is formed of a magnetic material having a thickness that does not saturate the magnetic flux (a material having a high magnetic permeability and a low magnetic resistance proportional to the inverse of the magnetic permeability), the vicinity thereof. The magnetic flux is concentrated on the magnetic shield cover 20. Therefore, the magnetic shield cover 20 collects a part or all of the leakage flux that tries to enter the resolver, particularly the resolver stator 10, and then a part or all of the leakage flux that flows out from the magnetic shield cover 20 enters the resolver. By eliminating it, it is possible to reduce the influence of the leakage flux on the resolver.

Since the influence of the leakage flux on the resolver depends on the positional relationship with the rotary electric machine stator 50 and the like, it is necessary to make adjustments according to the specific shape of the rotary electric machine. However, in general, as described with reference to FIGS. 2 to 4, it can be expected that the influence of the leakage flux can be reduced by covering the end surface of the stator core 12 on the rotary electric machine stator 50 side of the resolver stator 10. In the examples of FIGS. 2 to 4, the magnetic shield cover 20 is installed at a distance from the stator core 12 by sandwiching the non-magnetic member 70. By sandwiching the non-magnetic member 70 or air in between, the effect of preventing the magnetic coupling between the magnetic shield cover 20 and the stator core 12 can be enhanced. Further, in the examples of FIGS. 2 to 4, the magnetic shield cover 20 covers only the outer peripheral side of the coil end 16a. This makes it possible to reduce the weight of the magnetic shield cover 20. However, the area of the magnetic shield cover 20 may be expanded so as to cover a part or all of the end face of the coil end 16a (resin cover 14) on the rotary electric machine stator 50 side. Further, the area of the magnetic shield cover 20 may be expanded so as to cover a part or all of the side surface on the outer peripheral side of the stator core 12.

Further, it is also possible to allow a part or all of the magnetic flux concentrated on the magnetic shield cover 20 to flow to the rotary electric machine case 40 through the bolt 60 shown in FIG. In this case, the bolt 60 is made of a magnetic material, and the rotary electric machine case 40 can also be implemented by preparing a flow path for magnetic flux.

When the metal magnetic shield cover 20 is formed of a conductor, the effect of shielding the leakage flux (alternating magnetic flux), which fluctuates greatly with time, can be expected. In this case, an eddy current is generated in the magnetic shield cover 20 in response to the leakage flux that has entered, and the leakage flux can be reduced by generating a magnetic flux in the direction in which the eddy current cancels the leakage flux. Become.

The magnetic shield cover 20 can be a substance that is both a magnetic material and a conductor. For example, iron, nickel, etc. are substances having such properties. In addition, various alloys having such properties are known. It is also possible to use the magnetic shield cover 20 as a non-magnetic conductor. For example, austenitic stainless steel (SUS304, SUS304, etc.), which is a steel containing nickel and chromium, is a substance having such properties.

In any case, in providing the magnetic shield cover 20, it is necessary to avoid interference with the resin cover 14 or interference with the knock pin 30. Therefore, as shown in FIG. 2, the magnetic shield cover 20 is provided with a protruding portion 24 that protrudes toward the outer peripheral side and bypasses the annular portion 22 so as to prevent interference with the knock pin 30 and the stopper portion 14b. .. If the protruding portion 24 is not provided, the magnetic shield cover 20 will be formed by two members. However, by providing the protruding portion 24, the magnetic shield cover 20 can be made into one member and can be attached. It is possible to reduce the time and effort.

The width of the member in the protruding portion 24 is narrower than that of the annular portion 22. Therefore, it is conceivable that the shielding effect of the protruding portion 24 is smaller than that of the annular portion 22. Therefore, it is possible to form the width of the member in the protruding portion 24 equal to or wider than the annular portion 22. In this case, there is a concern that it may interfere with surrounding members such as the rotary electric machine case 40 or the rotary electric machine stator 50, but it may be formed into a shape that can be stored in a limited space by bending it or the like.

The magnetic shield cover 20 has a structure that does not cover the vicinity of the terminal cover portion 14a, but it is also possible to have a relief shape that protrudes to the outer peripheral side as in the vicinity of the stopper portion 14b. In this case, since the magnetic shield cover 20 can cover the resolver stator 10 all around, the effect of reducing the variation in the shield in the circumferential direction can be expected.

In the above description, the case where the knock pin 30 and the stopper 14b have a specific shape is taken as an example. However, the positions and shapes of the knock pin 30 and the stopper 14b can be changed in various ways. As an example, the knock pin 30 may be engaged with the engaging hole provided in the stator core 12 instead of the engaging groove 12b. Further, an example having a structure in which the stop portion 14b is in contact with or fits with the knock pin 30 can be mentioned. When the positions or shapes of the knock pin 30 and the stop portion 14b are changed, interference can be prevented by changing the position or shape of the protruding portion 24 of the magnetic shield cover 20 accordingly.

By mounting the rotary electric machine according to the present embodiment on the electric vehicle, the rotational position of the rotor of the rotary electric machine can be detected with high accuracy. As a result, it becomes possible to perform precise control of the electric vehicle, and it is expected that the ride quality and fuel efficiency will be improved. Further, the present embodiment can be applied to a rotary electric machine used other than an electric vehicle.

10, 102 Resolver stator, 12, 104 Stator core, 14, 106 Resin cover, 14a terminal cover, 14b, 106a Stop, 12a, 28a, 28b, 108 Long holes, 12b, 114 Engagement grooves, 16a, 16b, 54 Coil end 20 Magnetic shield cover, 22 ring part, 24 protrusion, 24a, 24b transition part, 26a, 26b, 26c, 26d, 26e round hole, 30, 112 knock pin, 40 rotary electric case, 42, 124 knock pin boss , 42a knock hole, 44, 122 stator boss, 44a boss hole, 50 rotary electric machine stator, 52 rotary electric machine stator core, 60 volt, 70 non-magnetic member, 100 resolver, 102 resolver stator, 110 threaded bolt, 120 motor case.

Claims (1)

A resolver rotor attached to the rotor shaft of a rotary electric machine,
A cylindrical resolver stator arranged around the resolver rotor,
With
The resolver stator has an engaging structure that engages with a knock pin having one end inserted into the case of the rotary electric machine, and the resolver stator is arranged so as to face the other end of the knock pin engaged with the engaging structure to prevent the knock pin from coming off. Equipped with a stopper to prevent
A magnetic shield cover is provided on the axial end surface of the resolver stator on the rotor side.
The magnetic shield cover is formed in the vicinity of the stopper portion in a shape in which the knock pin or the stopper portion is bypassed to the outer peripheral side.
A resolver characterized by that.

Images