JP4355922B2 - Electric pump - Google Patents

Description

  The present invention relates to a compact electric pump in which a pump chamber for circulating a liquid and an electric motor chamber in an air environment are arranged adjacent to each other, such as an on-vehicle water pump and an oil pump.

  In recent years, electric vehicles with less environmental impact and so-called hybrid cars with less exhaust gas have attracted attention, and those that have entered the practical stage have also appeared. Automobiles that use electric motors for these runs have no engine or perform intermittent operation, so it is necessary to replace the drive source with a motor for auxiliary equipment such as pumps that have been driven by an infinite belt that has been placed around the engine. There is.

  Conventionally, in this type of electric pump, the pump unit and the motor unit are formed separately, and the pump rotating shaft and the motor rotating shaft are connected to each other so as to be able to transmit the drive using a joint such as an Oldham joint. 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).

  4 is a schematic cross-sectional view showing a configuration of a conventional electric pump, and FIG. 5 is a cross-sectional view taken along the line AA in FIG.

  This example shows a gear pump used as a hydraulic pump for an automobile transmission, and an electric motor chamber (motor unit 2) and a pump chamber (pump unit 3) are formed inside the housing 1. . In the housing 1, there is provided a main shaft 4 that is a drive shaft that is rotationally driven by the motor portion 2 and also a rotational shaft of the pump portion 3, and is rotatably supported by ball bearings 8 and 9. In the figure, reference numeral 20 denotes a motor rotor portion, 21 denotes a magnet, 22 denotes a motor stator portion, 31 denotes a gear pump drive gear, 32 denotes a gear pump driven gear, and 33 denotes a support shaft that supports rotation of the driven gear, Reference numeral 34 denotes a side plate. Further, in order to prevent the explanation from becoming complicated, explanations of operations and functions of the members constituting the motor unit 2 and the pump unit 3 are omitted.

  The housing 1 is made of, for example, an aluminum alloy, and mainly includes a motor housing 12 in which the motor unit 2 is accommodated, a pump housing 13 in which the pump unit 3 is mainly accommodated, and a housing base body as a partition member for separating them. 11 are connected to each other. The housing base 11 is provided with a through hole 11a through which the main shaft 4 is inserted, and a liquid (working fluid) on the pump unit 3 side is provided by a seal member (oil seal) 10 disposed in the through hole 11a. ) Is prevented from entering the motor unit 2 side.

  The motor housing 12 includes a cylindrical portion 12a and a bottom portion 12b formed on one side in the axial direction (opposite side to the pump portion 3), and is formed in a bottomed cup shape having an open surface on the other side in the axial direction. . Further, a ball bearing 8 for supporting one end of the main shaft 4 is disposed at the radial center of the bottom 12 b of the motor housing 12.

  A large-diameter portion 4a for supporting the magnet 21 is formed on the motor portion 2 side (right side in the figure) of the main shaft 4. The large-diameter portion 4a and the magnet 21 constitute a motor rotor portion 20. Yes. Depending on the motor, instead of forming the large-diameter portion 4a integrally with the main shaft 4, a large-diameter portion 4a is formed by fitting a member in which a large number of electromagnetic steel plates are laminated on the outer periphery of a substantially cylindrical shaft. Some have.

  Further, a drive gear 31 and a driven gear 32 that mesh with each other are accommodated in the cavity 13a of the pump housing 13, and a side plate made of, for example, an aluminum alloy is disposed between the side surfaces of these gears 31 and 32 and the housing base 11. 34 is fitted. The side plate 34 is formed with an insertion hole 34 a that allows the main shaft 4 to pass therethrough and a support hole (not shown) that rotatably supports the support shaft 33 of the driven gear 32.

  According to this configuration, the rotary shaft of the electric motor unit 2 is configured on one end side of the single shaft (main shaft 4), and the rotary shaft of the pump unit 3 is configured on the other end side. Thus, a small and inexpensive electric pump can be provided by reducing the number of parts.

JP 2002-31065 A

  By the way, in the electric pump as described above, a bearing for supporting the rotating shaft and a seal member for preventing leakage of fluid from around the rotating shaft are separately arranged at different positions in the axial direction. The problem is that the axial dimension of the pump as a whole is inevitably increased.

  In addition, auxiliary machinery mounted on automobiles is always required to be smaller and lighter for energy saving (improving fuel efficiency) and cost reduction to improve competitiveness. There is a demand for a more compact and low-cost product while having functions and reliability equivalent to those of the prior art.

  The present invention has been made to address the above-described problems, and an object thereof is to provide a small and inexpensive electric pump having a small number of parts.

  In order to achieve the above object, according to the first aspect of the present invention, fluid is sucked and discharged on both sides of a rotating shaft that is inserted through a through hole provided in a partition member that partitions the housing. In an electric pump in which a pump unit and a motor unit that drives the pump are arranged, a sleeve that supports the rotation of the rotating shaft is fitted into a through hole portion of the partition member via an O-ring, and the sleeve is The fixed side seal ring is fitted, and the rotary side seal ring is fitted to the outer periphery of the rotary shaft on the motor side from the fixed side seal ring, and one of the fixed side seal ring and the rotary side seal ring is connected to the shaft. It is characterized by being pressed against the other ring by a direction pressing means and shaft-sealing the through hole.

  In the electric pump in which the pump part and the motor part are formed on both sides of a single rotating shaft, the present invention combines a bearing that supports the rotating shaft with a seal that seals the opening through which the rotating shaft is inserted. It is intended to achieve the intended purpose.

  In other words, according to the first aspect of the present invention, the bearing sleeve (also serving as the stationary seal ring) that supports the rotating shaft is fitted into the through hole portion of the member (partition member) that separates the pump chamber and the motor chamber. In addition, by forming a mechanical seal with the end face of this bearing sleeve as the sealed end face, the bearing and the seal member, which have been separately arranged in the past, are integrated, reducing the number of parts of the electric pump and simplifying the assembly work. Can be planned.

  In addition, since the bearing portion and the seal portion can be arranged at the same position in the axial direction, the degree of freedom in designing the electric pump can be improved and the dimensions in the axial direction can be shortened. Therefore, the electric pump can be reduced in size and weight.

  Next, the invention according to claim 2 is characterized in that the rotation-side seal ring is formed as a rotor portion of the rotation shaft.

  That is, instead of newly disposing a rotation-side seal ring on the outer periphery of the motor-side rotation shaft, a large-diameter portion is provided on the rotation shaft, and an end surface of the large-diameter portion is used as a sealing end surface on the rotation side. As a result, it is possible to further reduce the size and weight of the electric pump and reduce the cost.

  The form of the pump in the present invention is not particularly limited. In addition to a gear pump, a pump having a mechanism for pumping fluid by rotation of a member attached to one end of a shaft, such as a pump using a vane pump or an impeller. In addition, it is widely applicable. Further, the type of the electric motor is not particularly limited.

  As described above, according to the present invention, the axial dimension of the electric pump can be shortened, and the size and weight thereof can be reduced. Moreover, since the number of components to be configured is reduced and the assembling work is simplified, the cost of the electric pump can be reduced.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.
FIG. 1 is a schematic cross-sectional view showing the structure of an electric pump according to an embodiment of the present invention, and FIG. 2 is an enlarged view of a portion P in FIG. In addition, the same code | symbol is attached | subjected to the structural member which has a function similar to a prior art example, and detailed description is abbreviate | omitted.

  This example also shows a gear pump as in the conventional example, with the pump portion 3 on one end side (left side in the figure) of the main shaft 4 disposed in the housing 1 and the motor on the other end side (right side in the figure). Part 2 is formed. The housing 1 connects a motor housing 12 in which the motor unit 2 is mainly stored, a pump housing 13 in which the pump unit 3 is mainly stored, and a housing base 11 (partition member) that separates them. The housing base 11 is formed with a through hole 11a through which the main shaft 4 is inserted.

  A large-diameter portion 4 a that supports the magnet 21 of the motor is formed on the motor portion 2 side (right side in the drawing) of the main shaft 4, and the motor is formed by the large-diameter portion 4 a and the magnet 21. The rotor portion 20 is formed. The main shaft 4 is rotatably supported by a ball bearing 8 disposed on the bottom 12 b of the motor housing 12 and a bearing sleeve 5 described later.

  The feature of the electric pump in the present embodiment is that the sleeve 5 disposed to support the rotation of the main shaft 4 is a part of a mechanical seal (fixed-side seal ring) that seals the through hole 11a of the housing base 11. It is a point that is configured. As shown in FIG. 2, the sleeve 5 is fitted into the inner periphery of the through hole 11a of the housing base 11 via the O-ring 6, and is provided at the end by an axial pressing means (washer 7). The convex portion 5a thus pressed is pressed against the rotor portion 20 (end surface 4b of the large diameter portion 4a) formed on the main shaft 4.

  With the above configuration, the sleeve 5 constitutes a sliding bearing that supports the rotation of the main shaft 4 and at the same time, prevents the working fluid on the pump unit 3 side from entering the motor unit 2 side. Therefore, in the electric pump of this embodiment, the bearing for supporting the rotating shaft and the seal member for preventing leakage of fluid from around the rotating shaft are separately arranged at different positions in the axial direction. Compared with this electric pump, the axial dimension of the entire pump can be shortened.

  The sleeve 5 also serves as a stationary seal ring for the mechanical seal, and the large-diameter portion 4a of the main shaft 4 also serves as the rotation-side seal ring for the mechanical seal, thereby reducing the number of parts of the electric pump and simplifying the assembling work. Can be achieved. Therefore, the electric pump of the present invention can be reduced in size and weight, and the cost can be reduced.

  In the present embodiment, the convex portion 5a of the sleeve 5 is pressed against the large diameter portion 4a of the main shaft 4 constituting the rotor portion 20 to form a sealed portion. In the case of a motor formed by fitting a laminated member, the convex portion 5a may be pressed against the end face of the electromagnetic steel sheet.

  Further, a ring-shaped member serving as a rotation-side seal ring may be separately provided between the sleeve 5 and the large diameter portion 4a. However, since this configuration causes an increase in the number of parts, it goes without saying that it is disadvantageous in terms of cost.

  Furthermore, the shape of the shaft sealing portion (the convex portion 5a of the sleeve 5) in the present invention is not limited to the example in this embodiment, and any shape such as a conventionally known mechanical seal may be used. good. In this embodiment, the washer 7 is used as a means for pressing the sleeve 5 in the axial direction. Instead, an elastic body such as a metal plate or a spring bent so as to expand and contract in the axial direction is disposed. You may do it.

  Furthermore, as shown in the cross-sectional view of FIG. 3, an elastic body 14 that presses the ball bearing 8 on the motor unit 2 side in the axial direction is disposed on the bottom 12b of the motor housing 12, and the large-diameter portion 4a of the main shaft 4 is disposed. You may press against the sleeve 5. This configuration is suitable because the ball bearing can be preloaded without increasing the number of parts.

It is typical sectional drawing which shows the structure of the electric pump in embodiment of this invention. It is the P section enlarged view of FIG. It is typical sectional drawing which shows another structure of the electric pump in embodiment of this invention. It is typical sectional drawing which shows the structure of the conventional electric pump. FIG. 5 is a cross-sectional view taken along line AA in FIG. 4.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Housing 2 Motor part 3 Pump part 4 Spindle 4a Large diameter part (rotation side seal ring)
5 Sleeve (fixed side seal ring)
5a Convex 6 O-ring 7 Washer 8 Ball bearing 9 Ball bearing 10 Seal member 11 Housing base (partition member)
11a Through-hole 12 Motor housing 13 Pump housing 14 Elastic body 20 Rotor part 21 Magnet 22 Stator part 31 Drive gear 32 Driven gear 33 Support shaft 34 Side plate

Claims (2)

An electric pump in which a pump part for sucking and discharging fluid and a motor part for driving the pump are arranged on both sides of a rotary shaft arranged through a through hole provided in a partition member for dividing the housing In
A sleeve that supports the rotation of the rotating shaft is fitted into the through-hole portion of the partition member via an O-ring, and this sleeve is used as a fixed-side seal ring, and the rotating shaft closer to the motor than the fixed-side seal ring. The rotation-side seal ring is fitted on the outer periphery of the shaft, and either the fixed-side seal ring or the rotation-side seal ring is pressed against the other ring by an axial pressing means, and the through hole is shaft-sealed. An electric pump characterized by The electric pump according to claim 1, wherein the rotation-side seal ring is formed as a rotor portion of the rotation shaft.

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