JP5322028B2 - Motor rotor - Google Patents

Description

  The present invention relates to a motor rotor suitable for an electric motor mounted on an electric supercharger.

  In order to improve the internal combustion engine, a turbocharger (also referred to as “turbocharger”) that is driven by the exhaust gas of the internal combustion engine and compresses the intake air to supercharge is widely used. In addition, a turbocharger in which acceleration response is improved by incorporating an electric motor coaxially with the rotation shaft of the supercharger and assisting acceleration of the rotational drive of the compressor is also used. Such a supercharger having an electric assist function by an electric motor is called an electric supercharger.

  Briefly explaining the configuration of this type of electric supercharger, a supercharger rotor in which a turbine impeller and a compressor impeller are connected to both ends of a rotating shaft is rotatably supported in a housing. An electric motor is built in the housing. An electric motor rotor (motor rotor) is fixed on the same axis as the rotating shaft, and an electric motor stator (motor stator) is disposed around the rotor inside the housing. When the exhaust gas from the internal combustion engine is supplied to the turbine impeller, the turbine impeller is rotationally driven, and the compressor impeller coupled to the turbine impeller is rotationally driven, so that the intake air is compressed and supplied to the internal combustion engine. At this time, the electric motor assists the rotational drive of the compressor impeller.

  A motor rotor of such an electric supercharger is disclosed in Patent Document 1 below. FIG. 1 is an enlarged cross-sectional view of a motor rotor and an oil draining member of a conventional electric supercharger disclosed in Patent Document 1. The motor rotor includes an inner sleeve 102 inserted into the rotating shaft 101 of the supercharger, a permanent magnet 103 and a pair of end rings 104 surrounding the inner sleeve 102 around the axis, and the permanent magnet 103 and the end ring 104 around the axis. And a hollow cylindrical armoring 105 surrounded by. The armoring 105 is shrink-fitted so that the permanent magnet 103 and the end ring 104 can be sufficiently retained even in a situation where a large centrifugal force acts at the maximum rotational speed of the rotor.

  An oil draining member 108 is provided on the turbine impeller side of the inner sleeve 102 at a position between the seal plate 106 and the thrust bearing 107 so as to surround the rotary shaft 101 around the axis. The oil draining member 108 is fixed to the rotating shaft 101 and rotates together with the rotating shaft 101. Further, the oil draining member 108 is provided with a seal member 109, and the gap between the oil draining member 108 and the seal plate 106 is liquid-tightly sealed.

  Another type of motor rotor of an electric supercharger is disclosed in Patent Document 2 below. FIG. 2 is a cross-sectional view of a motor rotor of a conventional electric supercharger disclosed in FIG. The motor rotor includes an inner sleeve 201 inserted into the rotating shaft of the supercharger, a permanent magnet 202 surrounding the inner sleeve 201 around the axis, and a hollow cylindrical armoring 203 surrounding the permanent magnet 202 around the axis. Become. The armoring 203 is shrink-fitted so that the permanent magnet 202 can be sufficiently retained even in a situation where a large centrifugal force acts at the maximum rotational speed of the rotor. A portion of the inner surface of the inner sleeve 201 other than both ends has a larger inner diameter than the inner surfaces of both ends of the inner sleeve 201. Although not shown, in the motor rotor described in Patent Document 2, an oil draining member is disposed at a position adjacent to the inner sleeve 201.

JP 2007-336737 A US Pat. No. 6,085,527

  In the manufacturing process of the electric supercharger of Patent Document 1, when the armoring 105 strongly tightens the permanent magnet 103 or the end ring 104 by strong shrink fitting, the portion surrounded by the permanent magnet 103 or the end ring 104 by the pressure of the shrinking The inner wall of the inner sleeve 102 is deformed inward. Therefore, in order to fit the inner sleeve 102 to the rotating shaft 101, it is necessary to perform a process (inner diameter finishing process) for increasing the inner diameter of the inner sleeve 102 after the motor rotor is assembled. Therefore, since the inner diameter finishing process is performed, the number of processes for automating the assembly process is increased, and the cost is increased.

  Further, since the oil draining member 108 and the inner sleeve 102 are separately manufactured, the number of parts is increased, and it is necessary to strictly manage the geometric tolerance. Therefore, this was also a cause of high cost.

  Further, the inner sleeve 201 of the electric supercharger of Patent Document 2 can reduce the area of the inner wall of the inner sleeve 201 when the inner diameter finishing process is performed, as compared with the inner sleeve 102 of Patent Document 1. However, the point that it is necessary to carry out the inner diameter finishing processing is the same as that of Patent Document 1, and the cost is increased.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a motor rotor capable of omitting the inner diameter finishing process and further reducing the number of parts.

In order to solve the above problem, the motor rotor according to the present invention employs the following technical means.
That is, the motor rotor according to the present invention has a cylindrical sleeve shape having a first end surface and a second end surface constituting both end surfaces in the axial direction and surrounding the rotating shaft around the axis, and from the first end surface to the second end surface. A sleeve member comprising an oil drain portion extending axially to a predetermined position toward the predetermined position, an inner sleeve portion integrally coupled to the oil drain portion and extending axially to the second end surface, and the inner sleeve portion around the axis A surrounding permanent magnet, a first end ring that surrounds the inner sleeve portion around an axis and is in contact with one end surface on the first end face side of the permanent magnet, and surrounds the inner sleeve portion around the axis and of the permanent magnet. A second end ring in contact with the other end surface; and a hollow cylindrical armor ring surrounding the permanent magnet, the first end ring, and the second end ring in a tightened state around an axis. The oil draining portion is in contact with the rotation shaft on the inner surface and is concentrically fitted to the rotation shaft, and an inner diameter of the inner sleeve portion is first than an end surface on the first end surface side of the first end ring. It is characterized by being larger than the inner diameter of the oil draining part over a range from the position on the end face side to the second end face.

According to the above configuration, since the inner sleeve portion of the portion where the permanent magnet and the pair of end rings are present can be increased in advance as it is expected to be deformed in advance, the inner wall of the inner sleeve is reduced after the assembly of the motor rotor. The inner diameter finishing process for cutting can be omitted, and the cost can be reduced by the reduced number of processes.
Furthermore, since the number of parts can be reduced by integrating the oil draining member and the inner sleeve, the geometric tolerance can be relaxed and the cost can be reduced.

  Further, the second end surface of the sleeve member is flush with the end surface of the second end ring on the side opposite to the permanent magnet.

  By configuring the inner sleeve portion of the sleeve member in this manner, the contact area between the compressor impeller and the motor rotor can be increased, and the compressor impeller can be rotated more stably.

  According to the present invention, it is possible to obtain an excellent effect that the inner diameter processing can be omitted and the number of parts can be reduced.

It is a figure which shows the structure of the conventional motor rotor and oil draining member of patent document 1. FIG. It is sectional drawing which shows the structure of the motor rotor of the conventional patent document 2. It is sectional drawing which shows the structure of the electric supercharger provided with the electric motor which has a motor rotor concerning embodiment of this invention. It is a figure which shows the structure of the motor rotor concerning 1st Embodiment of this invention. It is sectional drawing of the sleeve member shown in FIG. It is a figure which shows the structure of the motor rotor concerning 2nd Embodiment of this invention.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, the same code | symbol is attached | subjected to the common part in each figure, and the overlapping description is abbreviate | omitted.

  FIG. 3 is an overall configuration diagram of the electric supercharger including the electric motor having the motor rotor according to the first embodiment of the present invention. In this figure, the electric supercharger 1 includes a rotating shaft 2, a compressor impeller 3, an electric motor 4, and a housing. In this example, the housing includes a bearing housing 5, a turbine housing 6, and a compressor housing 7.

  The rotating shaft 2 has a turbine impeller 8 at one end (left end in the figure). In this example, the turbine impeller 8 is integrally formed with the rotating shaft 2, but the present invention is not limited to this, and a configuration in which the turbine impeller 8 is separately attached may be used.

  The compressor impeller 3 is connected to the other end (right end in the figure) of the rotary shaft 2 so as to rotate integrally with a shaft end nut 9.

  The bearing housing 5 includes a journal bearing 10 that receives a radial load of the rotating shaft 2 and a thrust bearing 11 that receives a thrust load. The rotating shaft 2 is rotatably supported by the journal bearing 10 and the thrust bearing 11. The bearing housing 6 has a lubricating oil passage (not shown) for lubricating the journal bearing 10 and the thrust bearing 11.

The turbine housing 6 rotatably surrounds the turbine impeller 8 and is connected to the bearing housing 5. The turbine housing 6 includes a scroll chamber 6a into which exhaust gas is introduced from the outside, and an annular flow path 6b that guides the exhaust gas from the scroll chamber 6a to the turbine impeller 8.
Further, a plurality of nozzle blades 12 are arranged in the flow path 6b at regular intervals in the circumferential direction. The nozzle blade 12 is a variable nozzle blade, and it is preferable that the area of the flow path formed therebetween can be changed. However, the present invention is not limited to this and may be a fixed nozzle blade. Moreover, the form without the nozzle blade | wing 12 in the flow path 6b may be sufficient.

  The compressor housing 7 rotatably surrounds the compressor impeller 3 and is connected to the bearing housing 5. The compressor housing 7 includes a scroll chamber 7a into which compressed air is introduced, and an annular diffuser 7b that guides the compressed air from the compressor impeller 3 to the scroll chamber 7a.

The electric supercharger has a motor rotor 13 and a motor stator 14. The motor rotor 13 is a rotor of the electric motor, and the motor stator 14 is a stator of the electric motor. The motor rotor 13 and the motor stator 14 constitute a brushless AC motor.
It is preferable that this AC motor can cope with high-speed rotation (for example, at least 100,000 to 200,000 rpm) of the rotating shaft 2 and can perform rotational driving during acceleration and regenerative operation during deceleration. The drive voltage of the AC motor is preferably the same as or higher than the DC voltage of the battery mounted on the vehicle.

  In the electric supercharger configured as described above, when exhaust gas is introduced from the engine by the scroll chamber 6a, the turbine impeller 8 is rotationally driven by the exhaust gas. Then, the compressor impeller 3 connected to the turbine impeller 8 via the rotary shaft 2 is rotationally driven, and the intake air is compressed by the compressor impeller 3 and supplied to the engine. At this time, the electric motor 4 assists the rotational drive of the compressor impeller 3.

  The electric supercharger 1 includes a flow path forming sleeve 15 and a seal wall 16. The flow path forming sleeve 15 is in close contact with the outer peripheral surface of the motor stator 14 and the inner peripheral surface of the bearing housing 5, and forms a liquid-tight water-cooled jacket 15 a between the bearing housing 5. Cooling water is supplied to the water cooling jacket 15a from a cooling water supply port and a cooling water discharge port (not shown) and discharged. Seal members 17a and 17b (for example, O-rings) are provided between the bearing housing 5 and the flow path forming sleeve 15 so as to liquid-tightly seal the inside and outside of the water cooling jacket 15a.

  The seal wall 16 is fastened together with the flange portion 15 b of the flow path forming sleeve 15 between the bearing housing 5 and the compressor housing 7 in the axial direction. The seal wall 16 partitions the compressor housing 7 and the motor stator 14, and is in close contact with the compressor side of the flow path forming sleeve 15.

  FIG. 4 is an enlarged view of the first embodiment of the motor rotor 13 shown in FIG. 3. As shown in FIG. 4, the motor rotor 13 according to the first embodiment includes a rotating shaft 2, a sleeve member 18 having a cylindrical sleeve shape surrounding the rotating shaft 2, and a rotating shaft 2 that is disposed outside the sleeve member. A permanent magnet 19 surrounding the first end ring 20 and a second end ring 21 surrounding the rotary shaft 2 around the axis and sandwiching the permanent magnet 19 from both sides in the axial direction; A hollow cylindrical armor ring 22 that surrounds the end rings 20 and 21 around the shaft in a tightened state.

  In FIG. 4, the thrust bearing 11 is disposed on the turbine impeller side of the sleeve member 18. The thrust bearing 11 is sandwiched between the sleeve member 18 and the rotary shaft 2, and is disposed opposite to both sides of the thrust collar 23 and a disk-shaped thrust collar 23 that rotates integrally with the rotary shaft 2 and the sleeve member 18. A turbine side thrust bearing 24 and a compressor side thrust bearing 25 that prevent axial movement of the thrust collar 23 are provided.

  The permanent magnet 19 in the illustrated example has a configuration that is not divided in the axial direction, but has a configuration in which an insulating material such as a resin is interposed between a plurality of ring-shaped magnets that are divided in the axial direction (sliced). The iron loss can be reduced by this configuration.

  The first end ring 20 is installed on the turbine impeller side of the permanent magnet 19, and the second end ring 21 is installed on the compressor impeller side of the permanent magnet 19. Further, both end rings 20 and 21 are installed in contact with the end face of the permanent magnet 19.

  In the present embodiment, the hollow cylindrical permanent magnet 19 and the end rings 20 and 21 are fitted to the outer periphery of the hollow cylindrical sleeve member 18 inserted into the rotary shaft 2 with a weak interference fit. The motor rotor 13 of the present embodiment is sandwiched between other members from both sides in the axial direction and rotates integrally with the rotary shaft 2.

  Further, the armoring 22 is sufficient for the permanent magnet 19 and the end rings 20 and 21 so that the permanent magnet 19 and the end rings 20 and 21 do not idle even in a situation where a large centrifugal force acts at the maximum rotation speed of the motor rotor 13. The permanent magnet 19 and the end rings 20 and 21 are fitted to each other by a strong shrinkage that can apply a compressive load. The armoring 22, the first end ring 20 and the second end ring 21 are made of a nonmagnetic material.

  The sleeve member 18 has a cylindrical sleeve shape extending in the axial direction, and has a first end surface 18a and a second end surface 18b constituting both end surfaces in the axial direction. The first end face 18a is in contact with the thrust collar 23 in the illustrated example. The second end face 18 b is in contact with the compressor impeller 3.

  A ring groove 26 extending in the circumferential direction is formed between the first end surface 18 a and the second end surface 18 b of the sleeve member 18. An annular seal member 28 is fitted in the ring groove 26 to seal the space between the seal plate 27 and the sleeve member 18 in a liquid-tight manner. Such a seal structure prevents the lubricating oil scattered from the thrust bearing 11 side from entering the compressor impeller side. In this example, the seal plate 27 is fixed to the bearing housing 5 and partitions the compressor side thrust bearing 25 and the compressor impeller 3.

  FIG. 5 is a cross-sectional view of the sleeve member 18 shown in FIG. As shown in FIG. 5, the sleeve member 18 is integrated with the oil draining portion 18c extending from the first end surface 18a toward the second end surface 18b to a predetermined position (the position of the ring groove 26 in the illustrated example), and the oil draining portion 18c. And an inner sleeve portion 18d extending in the axial direction from the predetermined position (the position of the ring groove 26 in the illustrated example) to the second end face 18b. The oil drain part 18c and the inner sleeve part 18d are integrally formed.

  In addition, said predetermined position is defined as a position used as the boundary of the part which has a function as an oil draining member, and the part which has a function as an inner sleeve. Therefore, in the configuration example of FIG. 4, the position of the ring groove 26 is the above-mentioned predetermined position. However, when a seal structure without the ring groove 26 is employed, the portion sealed by the seal structure is the above-mentioned predetermined position. It becomes.

  The oil draining portion 18c functions to swing the lubricating oil outward in the radial direction by centrifugal force due to high speed rotation. Further, the oil draining portion 18 c is in contact with the rotating shaft 2 on the inner surface and is fitted concentrically with the rotating shaft 2. That is, the inner diameter d1 of the oil drain portion 18c is set to a size such that the inner surface is in contact with the outer peripheral surface of the rotating shaft 2 and is concentrically fitted to the rotating shaft 2.

The inner sleeve portion 18d has an inner diameter d2 that extends from the position on the first end surface 18a side to the second end surface 18b rather than the end surface 20a on the first end surface 18a side of the first end ring 20 than the inner diameter d1 of the oil drain portion 18c. Is also made large. That is, in the assembling operation, the permanent magnet 19 and the two end rings 20 and 21 are fitted to the sleeve member 18 with a weak interference fit, and then the armoring 22 is strongly shrink fitted to the permanent magnet 19 and the end rings 20 and 21. The inner diameter of the portion of the inner sleeve portion 18d where the permanent magnet 19 and the end rings 20, 21 are fitted is reduced by the compression load. For this reason, the amount of deformation due to the compressive load is estimated in advance, and the inner diameter of the inner sleeve portion 18d is made large so as to be larger than the outer diameter of the rotating shaft even after the inner diameter is reduced by taking into account the estimated amount of deformation.
Therefore, the sleeve member 18 is fitted to the rotary shaft 2 by the inner surface of the oil drain portion 18c and a part of the inner surface of the inner sleeve portion 18d close to the oil drain portion, so that the sleeve member 18 is radially directed to the rotary shaft 2. It is positioned.

  As described above, in the conventional motor rotor (FIG. 1), the inner sleeve 102 is subjected to the inner diameter finishing process after the permanent magnet 103, the end ring 104, and the armoring 105 are fitted to the inner sleeve 102 in the assembly process. Although it was necessary, in the motor rotor of the present invention, the inner diameter of the inner sleeve portion 18d where the inner diameter is reduced due to the compression load due to the fitting of the armoring 22 is larger than the outer diameter of the rotary shaft 2. Finishing can be omitted. Thereby, not only the process of an assembly work can be reduced, but the cost can be reduced accordingly.

  Further, by integrating the oil draining member and the inner sleeve, which were conventionally separate parts, and manufacturing it as a single sleeve member 18, the geometrical tolerance can be relaxed and the cost can be reduced as the number of parts is reduced. be able to.

  FIG. 6 is a diagram showing the configuration of the motor rotor according to the second embodiment of the present invention. In the second embodiment, the second end surface 18b of the sleeve member 18 and the end surface 21a opposite to the permanent magnet 19 of the second end ring 21 are flush with each other. Other configurations are the same as those of the first embodiment.

  With this configuration, not only the second end surface 18 b of the sleeve member 18 but also the end surface 21 a opposite to the permanent magnet 19 of the second end ring 21 can be brought into contact with the end surface on the back side of the compressor impeller 3. Thereby, the compressor impeller 3 can be rotated more stably than the first embodiment.

  As other effects, the inner diameter finishing process of the sleeve member 18 can be omitted, the geometrical tolerance can be loosened as the number of parts is reduced, and the cost can be reduced in the first embodiment. It is the same.

  Although the embodiments of the present invention have been described above, the embodiments of the present invention disclosed above are merely examples, and the scope of the present invention is not limited to these embodiments. The scope of the present invention is indicated by the description of the scope of claims, and further includes meanings equivalent to the description of the scope of claims and all modifications within the scope.

DESCRIPTION OF SYMBOLS 1 Electric supercharger 2 Rotating shaft 3 Compressor impeller 4 Electric motor 8 Turbine impeller 13 Motor rotor 14 Motor stator 18 Sleeve member 18a First end face 18b Second end face 18c Oil drain part 18d Inner sleeve part 19 Permanent magnet 20 First end ring 20a First End face 21 on the first end face 18a side of the end ring 20 Second end ring 21a End face 22 on the opposite side of the permanent magnet 19 of the second end ring 22 Armoring 26 Ring groove d1 Inner diameter d2 Inner sleeve inner diameter

Claims (2)

A cylindrical sleeve shape having a first end surface and a second end surface constituting both end surfaces in the axial direction and surrounding the rotation shaft around the axis is formed, and extends in the axial direction from the first end surface to a predetermined position toward the second end surface. A sleeve member comprising an oil draining part and an inner sleeve part integrally coupled to the oil draining part and extending in the axial direction to the second end surface;
A permanent magnet surrounding the inner sleeve portion around its axis;
A first end ring that surrounds the inner sleeve portion around an axis and is in contact with one end surface on the first end surface side of the permanent magnet;
A second end ring surrounding the inner sleeve portion around the axis and in contact with the other end surface of the permanent magnet;
A hollow cylindrical armor ring that surrounds the permanent magnet, the first end ring and the second end ring around an axis in a tightened state by shrink fitting ,
The oil drainer is in contact with the rotating shaft on the inner surface and is fitted concentrically with the rotating shaft,
An inner diameter of the inner sleeve portion is larger than an inner diameter of the oil draining portion over a range from the position on the first end face side to the second end face than the end face on the first end face side of the first end ring. A motor rotor characterized by that. The second end surface of the sleeve member is flush with an end surface of the second end ring on the side opposite to the permanent magnet ,
2. The motor rotor according to claim 1, wherein an end surface on a back surface side of a compressor impeller is in contact with the second end surface and the end surface of the second end ring .

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