JP4569750B2 - Electric pump unit - Google Patents

Description

  The present invention relates to a compact electric pump unit in which a pump chamber that circulates a liquid and an electric motor chamber that drives the pump chamber are disposed adjacent to each other, such as an on-vehicle water pump and an oil pump.

  In recent years, electric vehicles that have a low environmental impact, so-called hybrid cars that emit less exhaust gas, and idle stop cars that stop the engine when the vehicle is stopped have attracted attention. Since these automobiles are not equipped with an engine or are not always driven even if they are equipped, auxiliary equipment such as a pump that has been driven by a belt that has been stretched over the engine is a driving source. Need to be replaced with an electric motor.

  Conventionally, in this type of electric pump, the pump and the motor are formed separately, and the rotation shaft of the pump and the rotation shaft of the motor are connected to each other so as to be able to transmit the drive using a joint such as an Oldham joint. It was. However, in such a configuration, since bearings and oil seals are provided corresponding to the pair of shafts, the number of parts is large, the apparatus is large, and the manufacturing cost is high. In view of this, the present applicants have proposed a small and inexpensive electric pump unit by using both the rotation shaft of the motor and the rotation shaft of the pump as a single shaft (see Patent Document 1).

  FIG. 5 is an axial sectional view showing the structure of a conventional electric pump unit, and FIG. 6 is a sectional view taken along the line BB in FIG.

  This example shows a trochoid pump used as a hydraulic pump for an automobile transmission. In an adjacent section inside the housing 1, an electric motor chamber (motor unit 2), a pump chamber (pump unit 3), and Is formed. In addition, a main shaft 34 that is a drive shaft that is rotationally driven by the motor unit 2 and also a rotation shaft of the pump unit 3 is disposed in the housing 1.

  The housing 1 is made of, for example, an aluminum alloy, and includes a motor housing 1a as a cover of the motor unit 2, a pump housing 1b that mainly stores the pump unit 3, and a pump plate 1c that seals the opening of the pump housing 1b. Are connected. The pump housing 1b divides the pump portion 3 and the motor portion 2, and a hole (through hole) through which the main shaft 34 is inserted is provided at substantially the center in the radial direction.

  The motor unit 2 includes a stator core 7 having a plurality of teeth, a motor stator in which a coil 9 is wound via resin insulators 8 and 8, and a cylindrical permanent magnet (ring magnet) on the outer periphery of the rotor core 35. 36) is mainly composed of a motor rotor. The rotor core 35 is formed as a large-diameter portion of the main shaft 34, and one end portion of the main shaft 34 is rotatably supported via a rolling bearing 41 with respect to the motor housing 1a. The other end side of the main shaft 34 is rotatably supported by a pump housing 1b via a rolling bearing 42 and is sealed by an oil seal 43, and then passes through the pump housing 1b to pass through the pump portion. 3 In the figure, reference numeral 44 denotes an inner gear of the trochoid pump, and 45 denotes an outer gear of the trochoid pump.

  As shown in FIG. 6, a brushless motor having a surface magnet (SMP) structure is used for the motor of the electric pump unit as described above. The ring-shaped magnet 36 fixed around the rotor core 35 has a magnetized state. A magnet (radial anisotropic ring magnet) whose direction is a radial direction and whose direction is alternately opposite to the circumferential direction is used. Further, the rotor core 35 that supports the ring-shaped magnet 36 has a function as a back yoke that forms a magnetic path of magnetic flux emitted from the ring-shaped magnet 36.

  The ring-shaped magnet has a plurality of arc-shaped magnets having the same magnetization direction in the radial direction and equally divided in the circumferential direction, and the magnetization direction is alternately reversed in the circumferential direction on the outer periphery of the rotor core. There is also a structure (segment method) pasted in this order. Moreover, as a rotor core, the rotor core of another member formed by laminating electromagnetic steel sheets may be fixed to the outer periphery of the main shaft.

JP 2002-31065 A

  By the way, since the electric pump unit as described above is compact and lightweight, it may be used as a vehicle-mounted auxiliary pump for repeated rotations and stops. Therefore, such an electric pump unit is required to have a performance of quickly starting up from a rotation start instruction signal to a required number of rotations.

  Also, when the rotational speed control is performed to maintain the pressure of the fluid delivered from the pump, the follow-up of the actual rotational speed may be delayed from the instructed rotational speed due to the inertia of the rotating body. It was.

  The present invention has been made to address the above-described problems, and an object of the present invention is to provide a small and lightweight electric pump unit that has good responsiveness to an instruction signal even in applications in which rotation and stop are repeated. It is said.

    According to the first aspect of the present invention, there is provided a housing, a rotating shaft disposed through a through-hole provided between adjacent sections in the housing, and a plurality of supporting rotations of the rotating shaft. And a motor rotor including a ring-shaped permanent magnet on the other end side of the rotating shaft, and a pump portion for sucking and discharging fluid is formed on one end side of the rotating shaft. In the electric pump unit in which a motor unit including a motor stator arranged around the motor rotor is formed, the permanent magnet is a polar anisotropic ring magnet, and the permanent magnet is formed in a hollow shape. It is directly fixed to the outer periphery of the rotating shaft.

  The present invention aims to further reduce the inertia of a rotating body, and a polar anisotropic ring magnet is used on the outer periphery of a rotating shaft formed as a hollow shaft without using a back yoke (rotor core). Take the method of fixing directly. According to this configuration, it is possible to reduce the mass of the rotating body including the rotating shaft while maintaining the same performance as the conventional electric pump unit. Therefore, the electric pump unit having the configuration of the present invention can also be an electric pump unit that has a short rise time from the start of rotation to the required number of rotations and good response to the instruction signal.

  As described above, according to the present invention, it is possible to realize a small and lightweight electric pump unit having good response to an instruction signal even when used for repeated rotation and stop.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.
FIG. 1 is an axial sectional view showing a structure of an electric pump unit according to a reference embodiment of the present invention, and FIG. 2 is a sectional view taken along line AA in FIG.

  The electric pump unit in this reference embodiment also shows a trochoid pump used as a hydraulic pump for automobile transmission, and the basic configuration is the same as that of the conventional example. A motor section 2 and a pump section 3 are formed in adjacent sections inside the housing 1, and in this housing 1 is a drive shaft that is rotationally driven by the motor section 2 and at the same time the pump section 3. A main shaft 4 that also serves as a rotating shaft is arranged. The motor unit 2 includes a stator core 7 having a plurality of teeth, a motor stator in which a coil 9 is wound via resin insulators 8 and 8, and a cylindrical permanent magnet (ring) on the outer periphery of the rotor core 5. The motor rotor is mainly composed of a magnet 6).

  A feature of the electric pump unit in the present embodiment is that a polar anisotropic ring magnet is used as the ring-shaped magnet 6, and the rotor core 5 that supports the ring-shaped magnet 6 protrudes from the outer peripheral surface of the main shaft 4. It is formed in a flange shape (back yoke), and a hollow portion P that opens toward one side in the axial direction is formed in the inner diameter portion thereof. The rotor core 5 and the main shaft 4 are formed using a magnetic material (iron or the like), and the magnetic flux generated from the ring magnet 6 (polar anisotropic ring magnet) is thin as shown in FIG. A magnetic circuit is formed through the rotor core 5.

  With this configuration, the electric pump unit according to the present embodiment maintains the same performance as the pump unit using the conventional radial anisotropic ring magnet, while maintaining the mass of the rotating body including the rotor core 5 and the rotating shaft 4. (Inertia) is reduced. Therefore, this electric pump unit can shorten the rise time from the start of rotation to the required number of rotations and improve the response to the instruction signal. Further, the weight of the entire electric pump unit can be reduced as compared with the conventional product.

  Note that the shape of the rotor core 5 having the hollow portion P is not limited to the example in this embodiment. For example, the rotor core may have a T-shaped cross section that protrudes from the outer peripheral surface of the main shaft so that the hollow portions are provided on both sides in the axial direction, or a plurality of holes that penetrate in the axial direction from the end surface of the rotor core are formed in the circumferential direction. It is possible to reduce the weight of the motor also by a method or the like. Also, in the case of an electric pump unit including a rotor core formed by stacking electromagnetic steel plates, a plurality of holes penetrating in the axial direction from the end face of the rotor core may be formed at equal intervals in the circumferential direction.

 In the embodiment of the present invention, the main shaft 4 that supports the rotor core 5 in the reference embodiment is a hollow shaft, and furthermore, as shown in FIG. The ring magnet (ring-shaped magnet 16) was reduced in size, and the ring-shaped magnet 16 was directly fixed to a hollow shaft 14 having no flange as a rotor core (back yoke).

Next, FIG. 4 illustrates a second reference embodiment of the present invention.
FIG. 4 is an axial cross-sectional view showing the structure of the electric pump unit in the second reference embodiment of the present invention.

  The configuration of the electric pump unit in the present reference embodiment is basically the same as that of the electric pump unit in the first reference embodiment. A motor section 2 and a pump section 3 are formed in adjacent sections inside the housing 21. The housing 21 has a drive shaft that is rotated by the motor section 2 and at the same time the pump section 3. A main shaft 24 that also serves as a rotating shaft is disposed. The motor unit 2 includes a stator core 7 having a plurality of teeth, a motor stator obtained by winding a coil 9 via resin insulators 8 and 8, and a cylindrical permanent magnet (ring) on the outer periphery of the rotor core 25. The motor rotor is mainly composed of a magnet 26).

  A feature of the electric pump unit in this reference embodiment is that a ring-shaped magnet 26 made of a polar anisotropic ring magnet is fixed to a substantially cylindrical rotor core 25 attached to the outer periphery of the large-diameter portion 24a of the main shaft 24. At the same time, rolling bearings 41 and 42 for supporting the rotation of the main shaft 24 are disposed in annular spaces (hollow portions P and P) formed on both sides of the main shaft large diameter portion 24a. The rotor core 25 is formed using a magnetic material (iron or the like), and the magnetic flux generated from the ring-shaped magnet 26 (polar anisotropic ring magnet) is thin as in the first reference embodiment. A magnetic circuit is formed through the rotor core 25.

  With the above configuration, the electric pump unit of the present embodiment also reduces the mass (inertia) of the rotating body including the rotor core 25 and the rotating shaft 24 compared to the pump unit using the conventional radial anisotropic ring magnet. . Therefore, this electric pump unit can be an electric pump unit that has a short rise time from the start of rotation to a required number of rotations and is excellent in response to an instruction signal.

  In addition, the bearings 41 and 42 that are conventionally disposed on both ends of the rotor core are disposed within the axial width of the motor rotor and at positions radially inward of the motor rotor, so that the bearings 41 and 42 are occupied. It is possible to reduce the axial space that has been used. Therefore, the electric pump unit in the present embodiment can reduce the weight of the entire unit and the axial dimension thereof as compared with the conventional product.

  The shape of the rotor core 25 and the main shaft 24 is not limited to the example 3 in this reference embodiment, and the rotor core 25 and the main shaft 24 may be integrally formed. In addition, the motor can be further reduced in weight by, for example, a method of forming a plurality of holes extending in the axial direction from the end face of the large diameter portion 24a of the main shaft 24 in the circumferential direction.

  The structure of the motor and the pump in the present invention is not limited to the example in the above embodiment, and it is needless to say that the structure can be applied to other electric pump units such as a pump using an impeller and a vane pump. Yes.

It is an axial sectional view showing the structure of an electric pump unit in an embodiment that is a reference of the present invention. It is AA arrow sectional drawing of FIG. It is an axial sectional view showing another structural example of the electric pump unit in the embodiment of the present invention. It is an axial sectional view showing the structure of the electric pump unit in the second reference embodiment of the present invention. It is an axial sectional view showing the structure of a conventional electric pump unit. FIG. 6 is a cross-sectional view taken along line B-B in FIG. 5.

DESCRIPTION OF SYMBOLS 1,11,21 Housing 1a, 11a, 21a Motor housing 1b, 11b, 21b Pump housing 1c, 11c, 21c Pump plate 2 Motor part 3 Pump part 4 Main shaft 5 Rotor core (back yoke)
6 Ring-shaped magnet 7 Stator core 8 Insulator 9 Coil 14 Hollow shaft (main shaft)
16 Ring-shaped magnet 24 Main shaft 24a Large diameter portion 25 Rotor core 26 Ring-shaped magnet 34 Main shaft 35 Rotor core (back yoke)
36 Ring-shaped magnet 41, 42 Rolling bearing 43 Oil seal 44 Inner gear 45 Outer gear P Hollow part

Claims (1)

One end side of the rotating shaft, comprising: a housing; a rotating shaft disposed through a through hole provided between adjacent sections in the housing; and a plurality of bearings for supporting the rotation of the rotating shaft Is formed with a pump portion for sucking and discharging fluid, and on the other end side of the rotating shaft, a motor rotor provided with a ring-shaped permanent magnet, and a motor stator disposed around the motor rotor. In the electric pump unit in which the motor part is formed,
The electric pump unit characterized in that the permanent magnet is a polar anisotropic ring magnet, and the permanent magnet is directly fixed to the outer periphery of the rotating shaft formed in a hollow shape.

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