JP2013241838A - Fluid pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluid pump capable of suppressing the run-out of the rotation axis of a rotating shaft which supports the rotation of a motor rotor.SOLUTION: A fluid pump includes an outer rotor 8, an inner rotor 7, and housings 1, 2 which hold the outer rotor 8 and the inner rotor 7 and are provided with a suction port 4 for sucking a fluid into a space formed between the outer rotor 8 and the inner rotor 7, and a discharge port 5. The inner rotor 7 includes rotating shafts 21, 22 extending from the inner rotor 7 itself in the directions opposite to each other. A shaft support 30 is formed between the end 21a of one rotating shaft 21 and the housings 1, 2. The shaft support 30 includes a tapered portion 31 which projects in the direction of a second rotation axis Y and a recessed receiving surface 33 which supports the tilted surface 32 of the tapered portion 31. The tapered portion and the recessed receiving surface are formed at the end 21a of one rotating shaft and on the housings 1, 2, respectively.

Description

  The present invention relates to a fluid pump including a pump rotor, a rotating shaft that rotates the pump rotor, and a housing that includes the pump rotor and includes a shaft support portion of the rotating shaft.

  The fluid pump includes, for example, a rotor (motor rotor) at one end of the rotating shaft and a pump motor at the other end of the rotating shaft, and an intermediate portion of the rotating shaft is supported by a shaft support provided in the housing. It is pivotally supported (see, for example, Patent Document 1).

  In the fluid pump of Patent Document 1, a ball that abuts on the end of the rotating shaft on the motor side is provided. The ball in contact with the rotation shaft restricts the movement of the rotation shaft from the contact position of the rotation shaft toward the bottom of the motor housing while allowing the rotation of the rotation shaft. In this way, the electric pump is configured such that the ball is brought into contact with the end portion of the rotating shaft so that the stator and the rotor do not shift in the axial direction and the performance of the fluid pump does not deteriorate.

JP2012-26294A

  However, when the ball is in contact with the end of the rotating shaft as in the fluid pump of Patent Document 1, there is a possibility that the rotating shaft core of the rotating shaft is shaken during operation of the motor. When the rotating shaft core is shaken, the distance between the stator and the rotor becomes uneven, and the rotation of the fluid motor becomes unstable. In addition, the rotor may come into contact with the motor housing and the electric pump member may be damaged.

  An object of this invention is to provide the fluid pump which can suppress the blurring of the rotating shaft center of the rotating shaft which supports rotation of a motor rotor.

The first characteristic configuration of the fluid pump of the present invention includes an outer rotor that includes an internal tooth and is driven to rotate around a first rotation axis.
An inner rotor having outer teeth meshing with the inner teeth of the outer rotor, and rotating around a second rotation axis different from the first rotation axis;
A suction port that holds the outer rotor and the inner rotor, sucks fluid into a space formed between the outer rotor and the inner rotor, and discharges fluid from the space on the lower side in the rotational direction of the suction port A housing provided with a port,
The inner rotor includes a rotating shaft that extends in the opposite direction from the inner rotor itself, and a shaft support portion is formed between an end portion of one rotating shaft and the housing, and the shaft supporting portion is configured to rotate the one rotor. A point that is formed separately for each end of the shaft and the housing and protrudes along the direction of the second rotation axis, and a concave receiving surface that supports the inclined surface of the tip. It is in.

  According to this configuration, the shaft support portion is formed between the end portion of the one rotary shaft extending from the inner rotor and the housing, and the shaft support portion is separately provided with respect to the end portion of the one rotary shaft and the housing. A tapered portion that protrudes along the direction of the second rotation axis and a concave receiving surface that supports the inclined surface of the tapered portion are provided. The end of one rotating shaft of the inner rotor and the housing abut the concave receiving surface against the inclined surface of the tapered portion at the shaft support portion. Thereby, the inclined surface of a taper is supported by the concave receiving surface. One rotating shaft is supported by the concave receiving surface at its end, not by point support. Thereby, one rotating shaft is supported stably and the blurring of the rotating shaft center of a rotating shaft is suppressed. As a result, the motor of the electric pump rotates stably. In addition, since the possibility that the motor rotor contacts the surrounding motor housing is reduced, the durability of the electric pump is improved.

  A second characteristic configuration of the fluid pump according to the present invention is that the tapered portion is formed on the side opposite to the discharge port with respect to the inner rotor.

  Since there is a fluid discharge pressure at the discharge port of the electric pump, the inner rotor receives the fluid pressure on the side opposite to the discharge port due to the discharge pressure. Therefore, as in the present configuration, when the tapered portion is formed on the side opposite to the discharge port with respect to the inner rotor, one rotating shaft of the inner rotor can be easily brought into contact with the housing side by the discharge pressure. As a result, the contact state between the tapered surface of the tapered portion and the concave receiving surface is improved, and the rotating shaft can be stably supported.

  A third characteristic configuration of the fluid pump according to the present invention is that the tapered portion is formed at an end of the one rotating shaft, and the concave receiving surface is formed in the housing.

  When the housing is compared with the end of the rotating shaft that constitutes the shaft support, the housing with a larger processing area is easier to process. In addition, the end portion of the rotating shaft is easier to form the tapered portion than the concave receiving surface. Therefore, as in the present configuration, a taper is formed at the end of one rotating shaft, and a concave receiving surface is formed in the housing. Thereby, the axial support part comprised by a taper and a concave receiving surface can be formed easily.

It is a vertical side view of an electric pump. It is II-II arrow sectional drawing of FIG. It is a disassembled perspective view of an electric pump. It is a principal part enlarged view which shows the contact part of a housing and the edge part of a rotating shaft. It is a principal part enlarged view in other embodiment.

The fluid pump of the present invention includes a pump rotor housed in the pump body and a drive unit that drives the pump rotor so that the fluid sucked from the suction port provided in the pump body is discharged from the discharge port.
Hereinafter, an electric pump which is an example of a fluid pump according to the present invention will be described with reference to the drawings.

[Basic configuration]
As shown in FIGS. 1 to 3, a pump unit P that sucks and discharges oil as a fluid and a motor unit M that drives the pump unit P are accommodated in an internal space S of a pump housing H, and an electric pump. Is configured.

  This electric pump is used to supply lubricating oil for automobile engines and the like. The electric pump may be used for supplying fluid other than oil.

〔housing〕
The pump housing H includes a resin housing main body 1 and a resin lid body 2 that is attached in a positioning state by being fitted into the opening 1 </ b> A of the housing main body 1. The inner space S is sealed by fixing the lid body 2 by a welding technique or an adhesion technique. The housing 1 main body has a bottom wall portion 1B and a vertical wall portion 1C that rises from the bottom wall portion 1B in a region surrounding the bottom wall portion 1B, and an opening that opens at the protruding end position of the vertical wall portion 1C. It is formed into a bowl shape forming the part 1A.

  The lid body 2 forms an outer peripheral surface 2A whose dimensions are set so as to be in close contact with the inner peripheral surface of the opening 1A, and by the relative movement of the rotary shaft 20 shown in FIG. The lid 2 can be fitted into the opening 1A. In this fitted state, the opening 1A of the housing body 1 and the outer peripheral surface 2A of the lid body 2 are in close contact with each other, so that the housing body 1 and the lid body 2 are relative to each other in the direction perpendicular to the rotational axis Y. The movement is blocked and the positioning state is reached.

  A concave pump housing space Sp into which the pump unit P is fitted is formed in the bottom wall portion 1B of the housing body 1, and a suction port 4 and a discharge port 5 communicating with the pump housing space Sp are formed at the bottom of the pump housing space Sp. And are formed. A concave body-side support 1S that rotatably supports one end of the rotating shaft 20 of the motor unit M is formed at the bottom of the pump housing space Sp.

  A concave lid side support portion 2S that rotatably supports the other end of the rotary shaft 20 is formed on the inner wall portion 2B on the inner surface side of the lid body 2. The main body side support portion 1 </ b> S and the lid body side support portion 2 </ b> S are formed of a rotation axis Y of the rotation shaft 20 and a coaxial core. Further, a circular groove centered on the rotation axis Y is formed in the inner wall portion 2B of the lid body 2, and a seal ring 6 is fitted in this groove.

〔Pumping unit〕
The pump unit P includes an inner rotor 7 having a fitting hole 7A into which the rotary shaft 20 is fitted, and an outer rotor 8 in which an inner peripheral tooth portion 8G is engaged with an outer peripheral tooth portion 7G of the inner rotor 7. It is configured as a trochoid type as an inscribed pump.

  In the pump unit P, the axis of the inner rotor 7 is arranged on the same axis as the rotation axis (second rotation axis) Y, and the rotation axis of the outer rotor 8 is located at a position deviated from the rotation axis Y. (First rotation axis) X is arranged. When the rotary shaft 20 is driven to rotate, the inner rotor 7 rotates, and the outer rotor 8 rotates along with this rotation, sucking oil from the suction port 4 and discharging oil from the discharge port 5.

[Motor unit]
The motor unit M is configured as a brushless type including a disk-shaped motor rotor 11 connected to the rotary shaft 20 and an excitation unit 12 disposed at a position surrounding the motor rotor 11. A seal plate 13 made of a disc-shaped resin sheet is provided at a boundary position between the motor rotor 11 and the pump unit P. The motor rotor 11 is configured as a permanent magnet in which N poles and S poles appear alternately on the outer periphery, and the outer surface is smoothly finished. The excitation part 12 is formed in a ring shape by winding a coil 12B made of a conductor around a plurality of cores 12A made of laminated magnetic steel sheets and enclosing them in an insulating resin 12C by a technique such as insert molding. have.

  The excitation part 12 is set to an outer diameter dimension (a radial dimension centering on the rotation axis Y) with the outer periphery contacting the inner surface of the vertical wall part 1C while being accommodated in the housing body 1, and in this accommodated state, the lid When the body 2 is fitted in the opening 1A of the housing body 1, the thickness dimension (direction along the rotational axis Y) is in contact with the bottom wall 1B of the housing body 1 and the inner wall 2B of the lid 2. ) Is set.

  The motor unit M is configured such that the opening of the pump housing space Sp can be closed by the motor rotor 11 by setting the outer diameter of the motor rotor 11 to be larger than the opening diameter of the pump housing space Sp. Further, since the seal plate 13 described above is provided, the seal plate 13 closes the opening of the pump housing space Sp and suppresses the leakage of pressure oil from the pump housing space Sp toward the motor rotor 11.

  The motor rotor 11 may have a configuration in which a permanent magnet is attached to the outer periphery of a disk-shaped yoke. Further, a metal plate can be used as the seal plate 13, and the motor rotor 11 may be configured to directly close the opening of the pump housing space Sp without providing the seal plate 13.

  Although not shown in the drawings, this electric pump has a detecting means for detecting the rotational phase of the motor rotor 11 and has a power control section that selectively supplies power to the plurality of coils 12B of the excitation section 12. A control circuit is provided outside. By supplying electric power from the motor control circuit to the coil 12 </ b> B of the excitation unit 12, the magnetic force is applied to the motor rotor 11 from the excitation unit 12 to rotate the motor rotor 11. As a result of this rotation, the tooth portion 7G of the inner rotor 7 rotates and the outer rotor 8 having the tooth portion 8G meshing with the tooth portion 7G is driven to rotate, so that oil is sucked from the suction port 4 and oil is discharged from the discharge port 5. Is realized.

  In the present embodiment, the inner rotor 7 includes rotating shafts 21 and 22 that extend from the inner rotor 7 itself in opposite directions as the rotating shaft 20. One rotating shaft 21 extends to the side of the inner rotor 7 opposite to the discharge port 5, and the other rotating shaft 22 extends to the discharge port 5 side of the inner rotor 7. As shown in FIG. 4, a shaft support portion 30 of the rotating shaft 21 is formed between the end of one rotating shaft 21 and the lid body 2. The shaft support portion 30 is formed on the end portion 21a of the one rotation shaft 21, and is formed on the lid body 2 and a tapered portion 31 that protrudes along the direction of the rotational shaft core (second rotational shaft core) Y. And a concave receiving surface 33 that supports the inclined surface 32 of 31.

  In the inner rotor 7, the end 21 a of one rotating shaft 21 and the lid (pump housing) 2 have a concave receiving surface 33 in contact with the inclined surface 32 of the tapered portion 31 in the shaft support portion 30. As a result, the inclined surface 32 of the tapered portion 31 is supported by the concave receiving surface 33. The rotary shaft 21 is supported by the concave receiving surface 33 at its end 21a, not by point support. Thereby, the rotating shaft 21 is stably supported, and the rotating shaft 21 is prevented from shaking the rotating shaft core Y. As a result, the motor of the electric pump rotates stably. Moreover, since the possibility that the motor rotor 11 contacts the surrounding motor housing is reduced, the durability of the electric pump is improved.

  One rotating shaft 21 having a tip 31 formed at the end 21 a is provided on the side opposite to the discharge port 5 with respect to the inner rotor 7. There is a fluid discharge pressure at the discharge port 5 of the electric pump. For this reason, the inner rotor 7 receives a pressing force toward the side opposite to the discharge port 5 due to the discharge pressure. By utilizing this pressing force, one rotating shaft 21 of the inner rotor 7 can be easily brought into contact with the lid 2 side of the pump housing H. As a result, the contact state between the inclined surface 32 of the tapered portion 31 and the concave receiving surface 33 becomes good, and the one rotating shaft 21 can be stably supported.

  When comparing the pump housing H with the end 21a of the rotating shaft 21 constituting the shaft support portion 30, the pump housing H having a larger processing area is easier to process. Further, when the end 21 a of the rotating shaft 21 is processed, the tapered portion 31 is easier to form than the concave receiving surface 33.

[Other embodiments]
(1) In the above embodiment, an example in which the tapered portion 31 is formed on the end portion 21a of the one rotating shaft 21 and the concave receiving surface 33 is formed on the pump housing H has been shown, but as shown in FIG. A tapered portion 31 may be formed on the pump housing H, and a concave receiving surface 33 may be formed on the end 21 a of the rotating shaft 21. However, when comparing the pump housing H with the end 21a of the rotating shaft 21 constituting the shaft support 30, the pump housing H having a larger processing area is easier to process. Further, when the end 21 a of the rotating shaft 21 is processed, the tapered portion 31 is easier to form than the concave receiving surface 33.

(2) The portion of the concave receiving surface 33 that contacts the inclined surface 32 of the tapered portion 31 may have a surface shape that makes surface contact with the inclined surface 32. Since the inclined surface 32 and the concave receiving surface 33 are in surface contact with each other, the support region of the rotating shaft 21 by the shaft support portion 30 is increased, and the rotating shaft 21 can be stably supported. Further, the inclined surface 32 of the tapered portion 31 and the portion of the concave receiving surface 33 that contacts the inclined surface 32 may be curved surfaces.

  The fluid pump of the present invention can be applied to various pumps that pump a liquid in addition to an oil pump.

1 Housing body (housing)
2 Lid (housing)
4 Suction port 5 Discharge port 7 Inner rotor 7G Outer teeth 8 Outer rotor 8G Inner teeth 20 Rotating shaft 21 One rotating shaft 21a End 22 The other rotating shaft 30 Axial support portion 31 Tip 32 Inclined surface 33 Concave receiving surface H Pump housing X 1 rotation axis Y Y rotation axis (second rotation axis)

Claims (3)

An outer rotor having inner teeth and driven to rotate about the first rotation axis;
An inner rotor having outer teeth meshing with the inner teeth of the outer rotor, and rotating around a second rotation axis different from the first rotation axis;
A suction port that holds the outer rotor and the inner rotor, sucks fluid into a space formed between the outer rotor and the inner rotor, and discharges fluid from the space on the lower side in the rotational direction of the suction port A housing provided with a port,
The inner rotor includes a rotating shaft that extends in the opposite direction from the inner rotor itself, and a shaft support portion is formed between an end portion of one rotating shaft and the housing, and the shaft supporting portion is configured to rotate the one rotor. A fluid comprising a tapered portion formed along the end of the shaft and the housing and projecting along the direction of the second rotating shaft core, and a concave receiving surface that supports an inclined surface of the tapered portion. pump.   The fluid pump according to claim 1, wherein the tapered portion is formed on the side opposite to the discharge port with respect to the inner rotor.   The fluid pump according to claim 1 or 2, wherein the tapered portion is formed at an end of the one rotating shaft, and the concave receiving surface is formed in the housing.

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