JP2007205246A - Water pump and hybrid vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water pump with sufficiently reduced vibration or noise and excellent in efficiency of a motor, and to provide a hybrid vehicle incorporating a water pump. <P>SOLUTION: The water pump 10 has a pump shaft 24 which rotates, and the motor 50 giving torque to the pump shaft 24. The motor 50 has electromagnetic steel sheets 51 fixed to the pump shaft 24, and permanent magnets 52 embedded in the electromagnetic steel sheets 51. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates generally to a water pump and a hybrid vehicle, and more specifically to a water pump driven by a motor and a hybrid vehicle equipped with the water pump.

  Regarding a conventional water pump, for example, Japanese Patent Application Laid-Open No. 2000-213498 discloses an electric fluid pump intended to enable lubrication and cooling of a bearing that supports an end portion of a rotor (patent). Reference 1). The electric fluid pump disclosed in Patent Document 1 includes a rotor having a permanent magnet disposed on an outer peripheral surface.

  Japanese Patent Application Laid-Open No. 11-166500 discloses a pump that aims to improve the cooling performance of components and a stator that generate a large amount of heat, such as a power IC of a control circuit (Patent Document 2). The pump disclosed in Patent Document 2 includes a motor that drives the pump. The rotor of the motor is configured as a permanent magnet rotor in which a permanent magnet magnetized with a plurality of poles is attached to an outer peripheral portion of a cylindrical rotor core. The entire rotor is molded with resin.

Japanese Patent Laid-Open No. 6-88591 aims to reduce the air gap between the permanent magnet on the rotating side and the permanent magnet on the fixed side, and to protect the bearing surface of the permanent magnet from wear and corrosion. A canned motor pump is disclosed (Patent Document 3). In Patent Document 3, a hollow cylindrical thin plate having a small thickness is fixed to the outer peripheral surface of a rotating permanent magnet fitted into a yoke by welding or the like, or thin plating is applied.
JP 2000-213498 A JP 11-166500 A JP-A-6-88591

  The electric fluid pump disclosed in Patent Document 1 uses a motor in which a permanent magnet is attached to the surface of a rotor, that is, a surface permanent magnet (SPM) motor. However, when the SPM motor is used, the shape error and assembly error of the permanent magnet appear directly as the coaxial deviation of the rotor. For this reason, there exists a possibility that the vibration and noise which generate | occur | produce with a pump may become large. Moreover, in the above-mentioned Patent Document 2, since the resin is also disposed around the permanent magnet, the motor efficiency may be reduced.

  Accordingly, an object of the present invention is to solve the above-described problems, and to provide a water pump that is sufficiently reduced in vibration and noise and that is excellent in motor efficiency, and a hybrid vehicle equipped with the water pump. is there.

  The water pump according to the present invention includes a rotating pump shaft and a motor that applies a rotational force to the pump shaft. The motor includes an electromagnetic steel plate fixed to the pump shaft and a permanent magnet embedded in the electromagnetic steel plate.

  According to the water pump configured in this manner, the coaxial displacement of the rotating body of the water pump can be reduced by embedding the permanent magnet, which is likely to cause a shape error and an assembly error, in the electromagnetic steel sheet. Thereby, the noise and vibration which generate | occur | produce with a water pump can be restrained small. Moreover, since an electromagnetic steel plate is arrange | positioned around a permanent magnet, motor efficiency can be improved. Thereby, size reduction of a water pump is attained.

  Preferably, the pump shaft is made of a resin material. The electromagnetic steel sheet is integrated with the pump shaft during resin molding of the pump shaft. According to the water pump configured as described above, it is possible to reduce the coaxial deviation of the rotating body of the water pump by improving the accuracy of the mold used at the time of resin molding.

  Preferably, the motor further includes a stator core around which a coil is wound. The electromagnetic steel sheet is exposed from the pump shaft at a position facing the stator core. According to the water pump configured as described above, since the resin is not disposed between the electromagnetic steel sheet and the stator core, the motor efficiency can be improved.

  A pumping fluid is disposed around the pump shaft. Preferably, the surface of the electromagnetic steel sheet and the permanent magnet is plated. According to the water pump configured as described above, the corrosion resistance of the electromagnetic steel sheet and the permanent magnet can be ensured.

  A hybrid vehicle according to the present invention is equipped with any one of the above-described water pumps, and uses an engine and a drive motor as power sources. According to the hybrid vehicle configured as described above, the quietness in the vehicle compartment can be maintained in a mode in which power is obtained only from the drive motor and no engine noise is generated.

  The water pump is housed in the engine room of the vehicle together with the engine and the drive motor. According to the hybrid vehicle configured as described above, the water pump can be installed in a limited space in the engine room in which the engine and the drive motor are accommodated by downsizing the water pump.

  As described above, according to the present invention, it is possible to provide a water pump in which vibration and noise are sufficiently reduced and motor efficiency is excellent, and a hybrid vehicle equipped with the water pump.

  Embodiments of the present invention will be described with reference to the drawings. In the drawings referred to below, the same or corresponding members are denoted by the same reference numerals.

  FIG. 1 is a perspective view showing a cooling system of an HV (Hybrid Vehicle) system. The cooling system of the HV system shown in the figure is mounted on a hybrid vehicle that is driven by a motor and an internal combustion engine such as a gasoline engine or a diesel engine.

  Referring to FIG. 1, the hybrid vehicle includes an engine 92, a transaxle 93 incorporating a drive motor and a generator for power generation, and a battery (not shown) mounted at the rear of the rear seat. An inverter 91 is provided at a position adjacent to the engine 92 for converting a direct current of the battery into an alternating current introduced into the motor. The hybrid vehicle further includes a radiator 81 provided on the back side of the front grille in front of the vehicle.

  The radiator 81 is provided with two independent cooling water channels, one of which constitutes the cooling system of the engine 92 and the other of which constitutes the cooling system of the HV system. The cooling system of the HV system is formed by a cooling water path that follows the radiator 81 → the inverter 91 → the reservoir tank 94 → the water pump 10 → the transaxle 93 → the radiator 81. Cooling water (for example, ethylene glycol coolant) in the water channel is forcibly circulated by the water pump 10 to cool the inverter 91 and the generator and motor provided in the transaxle 93. The temperature of the cooling water whose temperature has increased due to cooling passes through the radiator 81 and is lowered.

  The water pump 10 is housed in an engine room of a hybrid vehicle together with an engine 92 and a transaxle 93 incorporating a drive motor.

  FIG. 2 is a cross-sectional view showing the water pump in FIG. Referring to FIG. 2, water pump 10 is an electric pump driven by a motor. The water pump 10 is a centrifugal pump in which an impeller that pumps cooling water is disposed in a spiral chamber that extends in an annular shape.

  The water pump 10 includes a pump case 31 constituting a pump body, a support shaft 21 fixed to the pump case 31, a pump shaft 24 rotatably supported by the support shaft 21, and a rotation to the pump shaft 24. And a motor 50 for applying force.

  The support shaft 21 has one end 21m and the other end 21n, and extends from the one end 21m to the other end 21n along the central axis 101. The support shaft 21 does not rotate when the water pump 10 is driven and is stationary. The support shaft 21 is made of metal. In the present embodiment, the support shaft 21 is made of stainless steel.

  The pump shaft 24 has a shape extending in a cylindrical shape along the central axis 101. The pump shaft 24 is fitted on the outer periphery of the support shaft 21. The pump shaft 24 is supported by the support shaft 21 so as to be rotatable about the central axis 101. The pump shaft 24 rotates when the water pump 10 is driven. The pump shaft 24 is made of a resin material.

  The support shaft 21 has an outer peripheral surface 21a, and the pump shaft 24 has an inner peripheral surface 24b. As the pump shaft 24 rotates, the outer peripheral surface 21a and the inner peripheral surface 24b slide. The pump shaft 24 is rotatably supported with respect to the support shaft 21 by a sliding bearing having the outer peripheral surface 21a and the inner peripheral surface 24b as sliding surfaces. The outer peripheral surface 21a has a diameter of 10 mm or less, for example.

  An impeller 25 is integrally formed on the pump shaft 24. A plurality of impellers 25 are provided at intervals in the circumferential direction around the central axis 101. When the water pump 10 is driven, the impeller 25 rotates around the central axis 101 together with the pump shaft 24. The impeller 25 may be formed separately from the pump shaft 24 and fixed to the pump shaft 24.

  The pump shaft 24 is provided with a plurality of laminated electromagnetic steel plates 51 and permanent magnets 52 embedded in the electromagnetic steel plates 51. On the outer periphery of the electromagnetic steel plate 51, a coil 42 to which a three-phase current is supplied and an electromagnetic steel plate 41 as a stator core around which the coil 42 is wound are provided. The electromagnetic steel plate 51 and the permanent magnet 52 constitute a rotor of the motor 50 together with the pump shaft 24. The electromagnetic steel plate 41 and the coil 42 constitute a stator of the motor 50. The impeller 25 and the motor 50 are provided apart from each other in the axial direction of the central shaft 101.

  The pump case 31 is formed from a resin material. The pump case 31 forms a spiral chamber 35 in which the impeller 25 is accommodated. The spiral chamber 35 extends annularly around the central axis 101. The pump case 31 has a support portion 36 that supports one end 21 m of the support shaft 21.

  A partition wall 38 is fixed to the pump case 31. The partition 38 partitions the internal space 30 in which the electromagnetic steel plate 51 and the permanent magnet 52 are arranged, and the external space in which the electromagnetic steel plate 41 and the coil 42 are arranged. The internal space 30 is connected to the spiral chamber 35 and is filled with cooling water.

  The pump case 31 has a suction part 32 and a discharge part 33. The suction part 32 communicates with the spiral chamber 35 from the direction along the central axis 101. The discharge unit 33 communicates with the spiral chamber 35 at a predetermined phase around the central axis 101. The cooling water is introduced into the spiral chamber 35 through the suction part 32. The cooling water is pressurized by the impeller 25 rotating in the spiral chamber 35 and is pumped to the external pipe through the discharge unit 33. When the water pump 10 is driven, cooling water is supplied between the outer peripheral surface 21 a of the support shaft 21 that forms a sliding surface and the inner peripheral surface 24 b of the pump shaft 24.

  FIG. 3 is a diagram showing a detailed shape of the motor in FIG. FIG. 4 is a cross-sectional view of the motor taken along line IV-IV in FIG. With reference to FIGS. 3 and 4, the water pump 10 uses an interior magnet (IPM) motor. The detailed shape will be described below.

  The electromagnetic steel plate 51 is typically a silicon steel plate containing iron and silicon. The electromagnetic steel plate 51 is formed in a thin disk shape. A plurality of electromagnetic steel plates 51 are stacked along the central axis 101. The plurality of laminated electromagnetic steel plates 51 are integrally held by the resin that forms the pump shaft 24. The electromagnetic steel plate 51 has an outer peripheral surface 51 a that faces the electromagnetic steel plate 41 through the partition wall 38. The outer peripheral surface 51 a is exposed from the resin forming the pump shaft 24.

  Holes 51 h are formed in the plurality of laminated electromagnetic steel plates 51. The hole 51 h penetrates in the axial direction of the central shaft 101. A plurality of holes 51h are formed at intervals in the circumferential direction around the central axis 101. The hole 51h has a substantially rectangular opening surface.

  A permanent magnet 52 is inserted into the hole 51h. The permanent magnet 52 is embedded in the electromagnetic steel sheet 51 inside the outer peripheral surface 51a. A gap 55 is formed between the inner wall of the electromagnetic steel sheet 51 that defines the hole 51 h and the permanent magnet 52. The gap 55 is filled with resin, and the permanent magnet 52 is held in the hole 51h by the resin.

  In the present embodiment, the gap 55 is filled with the resin that forms the pump shaft 24. That is, the plurality of electromagnetic steel plates 51 and the permanent magnets 52 are integrated with the pump shaft 24 by the resin forming the pump shaft 24. Since the resin forming the pump shaft 24 is disposed around the permanent magnet 52, the permanent magnet 52 is prevented from dropping from the electromagnetic steel sheet 51 even though the permanent magnet 52 is disposed in the internal space 30 filled with cooling water. It can be surely prevented.

  The surfaces of the electromagnetic steel plate 51 and the permanent magnet 52 are plated. In the present embodiment, nickel (Ni) plating is applied to the surfaces of the electromagnetic steel sheet 51 and the permanent magnet 52. With such a configuration, the electromagnetic steel sheet 51 and the permanent magnet 52 can be prevented from being rusted by the cooling water filling the internal space 30.

  The partition wall 38 includes a cylindrical portion 40 and a support portion 39. The cylindrical portion 40 extends in a cylindrical shape along the axial direction of the central axis 101 so as to surround the outer periphery of the electromagnetic steel plate 51. A gap is formed between the electromagnetic steel plate 51 and the cylindrical portion 40. The support portion 39 has a concave shape, and the other end 21n of the support shaft 21 is press-fitted from the inner space 30 side.

  With this configuration, in the present embodiment, the support portion 39 that supports the support shaft 21 is formed integrally with the cylindrical portion 40. For this reason, the coaxial shift | offset | difference which arises between the support shaft 21 and the cylinder part 40 can be restrained small. Thereby, it is possible to prevent a deviation from occurring in the size of the gap between the cylindrical steel portion 40 and the electromagnetic steel plate 51 that is provided integrally with the pump shaft 24 and rotates around the support shaft 21.

  FIG. 5 is a flowchart showing the steps of the method for manufacturing the pump shaft in FIG. Referring to FIG. 5, a method for manufacturing the pump shaft 24 will be described. First, a plurality of electromagnetic steel plates 51 are stacked while aligning the positions of the holes 51 h. Ni plating is provided on the surfaces of the electromagnetic steel sheet 51 and the permanent magnet 52. The lamination process and the plating process of the electromagnetic steel sheet 51 may be performed before and after. That is, a plurality of electromagnetic steel sheets 51 may be stacked after Ni plating is provided on the surface of the electromagnetic steel sheet 51.

  Next, the permanent magnet 52 is inserted into the hole 51h. The electromagnetic steel plate 51 and the permanent magnet 52 are installed in a mold for resin-molding the pump shaft 24. At this time, the permanent magnet 52 is positioned in the hole 51h by using a pin provided in the mold. Inject resin material into the mold. The resin material enters the gap 55, holds the permanent magnet 52 in the hole 51h, and forms the pump shaft 24. Through the above steps, the pump shaft 24 in which the electromagnetic steel plate 51 and the permanent magnet 52 are integrally provided is completed.

  In the present embodiment, the resin mold that holds the permanent magnet 52 in the hole 51h and the resin mold that forms the pump shaft 24 are collectively performed. However, both resin molds may be performed separately. .

  The water pump 10 according to the embodiment of the present invention includes a rotating pump shaft 24 and a motor 50 that applies a rotational force to the pump shaft 24. The motor 50 includes an electromagnetic steel plate 51 fixed to the pump shaft 24 and a permanent magnet 52 embedded in the electromagnetic steel plate 51.

  According to the water pump 10 in the embodiment of the present invention configured as described above, by using the IPM motor, it is possible to reduce the coaxial deviation of the rotor shape that rotates in the pump. That is, in the present embodiment, since the permanent magnet 52 is embedded in the electromagnetic steel plate 51, a shape error or an attachment error of the permanent magnet 52 does not appear as a rotor shape error. For this reason, the accuracy of the rotor shape is determined by the accuracy of the mold used at the time of resin molding of the pump shaft 24. Thereby, the coaxial shift | offset | difference with respect to the rotor-shaped center axis | shaft 101 can be reduced, and the vibration and noise which generate | occur | produce in the water pump 10 can be reduced. In addition, in the IPM motor, since the rotation radius of the permanent magnet 52 is smaller than that of the SPM motor, the rotation balance of the rotor can be improved.

  In this case, for example, even if the hybrid vehicle is in a mode in which a driving force is obtained only by a driving motor built in the transaxle 93, it is possible to prevent the quietness in the vehicle compartment from being impaired.

  In the present embodiment, the outer peripheral surface 51 a of the electromagnetic steel plate 51 is exposed from the resin forming the pump shaft 24. For this reason, the magnetic flux flow between the electromagnetic steel plate 51 on the rotor side and the electromagnetic steel plate 41 on the stator side is not hindered by the resin. Thereby, motor performance can be improved and the water pump 10 can be reduced in size. Further, the water pump 10 can be housed in a limited space in the engine room by downsizing the water pump 10.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a perspective view which shows the cooling system of an HV system. It is sectional drawing which shows the water pump in FIG. It is a figure which shows the detailed shape of the motor in FIG. It is sectional drawing of the motor along the IV-IV line | wire in FIG. It is a flowchart which shows the process of the manufacturing method of the pump shaft in FIG.

Explanation of symbols

  10 Water pump, 24 Pump shaft, 41, 51 Electrical steel plate, 42 Coil, 50 Motor, 52 Permanent magnet, 92 Engine, 93 Transaxle.

Claims (6)

A rotating pump shaft;
A motor for applying a rotational force to the pump shaft,
The motor is a water pump having an electromagnetic steel plate fixed to the pump shaft and a permanent magnet embedded in the electromagnetic steel plate. The pump shaft is formed from a resin material,
The water pump according to claim 1, wherein the electromagnetic steel plate is integrated with the pump shaft during resin molding of the pump shaft. The motor further includes a stator core around which a coil is wound,
The water pump according to claim 2, wherein the electromagnetic steel sheet is exposed from the pump shaft at a position facing the stator core. A pumping fluid is disposed around the pump shaft,
The water pump according to any one of claims 1 to 3, wherein a surface of the electromagnetic steel plate and the permanent magnet is plated.   A hybrid vehicle equipped with the water pump according to any one of claims 1 to 4 and using an engine and a drive motor as power sources.   The hybrid vehicle according to claim 5, wherein the water pump is housed in an engine room of the vehicle together with the engine and the drive motor.

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