JP2017122459A - Electric oil pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem that, in a conventional electric oil pump, as a position of receiving a hydraulic pressure between rotors is offset from a support portion of the inner rotor and the inner rotor is inclined, friction is increased and collision noise easily occurs between the rotors.SOLUTION: An electric oil pump comprises a drive part and a pump part. The pump part comprises an inner rotor 102 rotated by a pump rotation shaft from the drive part, an outer rotor 103 provided outside of the inner rotor 102, and a pump housing in which the inner rotor 102 and the outer rotor 103 are housed. A bearing part 132 is provided in the pump housing for bearing force, which radially acts on the inner rotor 102 by a fluid pressure, at a position almost coincident with the force in the axial direction of a pump rotation shaft 27.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an electric oil pump that controls the flow of oil.

  2. Description of the Related Art Conventionally, an electric pump unit that operates a gear pump (trochoid type) using a brushless DC motor as a drive source is known (see, for example, Patent Document 1).

  As an example, there is an electric oil pump 801 as shown in FIG. In such an electric oil pump 801, a boss portion 803 is formed in the inner rotor 802, and the inner rotor 802 is rotatably supported by the boss portion 803.

  A shaft 805 of a motor 804 is inserted into the boss portion 803 and is configured to be rotationally driven by the shaft 805.

JP 2010-112302 A

  However, in such a conventional electric oil pump 801, the position where the inner rotor 802 receives the hydraulic pressure 812 between the outer rotor 811 and the support portion 812 of the inner rotor 802 is offset as shown in FIG. The inner rotor 802 may be inclined.

  In this case, the friction 822 may increase between the inner rotor 802 and the outer rotor 811 and the pump body 821, or the friction 823 may increase between the boss portion 803 and the pump body 821. In addition, there is a problem that a collision sound is easily generated between the inner rotor 802 and the outer rotor 811 824.

  The present invention has been made in view of such a conventional problem, and an object of the present invention is to provide an electric oil pump having a simple configuration and low friction and low noise.

In order to solve the above problems, an electric oil pump according to one aspect of the present invention includes an electric rotor including an inner rotor that is rotated by a pump rotation shaft from a driving unit and an outer rotor that is provided outside the inner rotor. In the oil pump, a bearing portion is provided that supports the force acting in the radial direction of the inner rotor due to the fluid pressure at a position substantially coincident with the axial direction of the pump rotation shaft.
An electric oil pump according to one aspect of the present invention includes a drive unit and a pump unit, and the pump unit is provided on an outer side of the inner rotor rotated by a pump rotation shaft from the drive unit, and the inner rotor. And a pump housing in which the inner rotor and the outer rotor are accommodated, and supports a force acting in the radial direction of the inner rotor due to fluid pressure at a position substantially coincident with the axial direction of the pump rotating shaft. A bearing portion is provided on the pump housing.
An electric oil pump according to one aspect of the present invention is an electric oil pump including an inner rotor that is rotated by a pump rotation shaft from a drive unit and an outer rotor that is provided outside the inner rotor. A bearing portion that supports a force acting in the radial direction at a position substantially coincided with the axial direction of the pump rotation shaft is provided, a first clearance between the inner rotor and the bearing portion, and an inclination amount due to rigidity of the bearing portion And a dimension obtained by adding a deviation amount of the drive unit and the central axis of the bearing portion is smaller than a sixth clearance between the boss portion extending from the inner rotor and the boss portion surrounding surface surrounding the boss portion. It is characterized by setting as follows.
An electric oil pump according to one aspect of the present invention includes a drive unit having a pump rotation shaft, and is connected to the pump rotation shaft on one side in the axial direction of the pump rotation shaft and rotates on the one side in the axial direction. An inner rotor having a supported hole, an outer rotor that surrounds the inner rotor and rotates with the rotation of the inner rotor, and extends from the inner rotor to the other side in the axial direction. And a boss part to which rotation of the pump rotating shaft is transmitted, and a bearing part inserted into the supported hole, and the drive part is a brushless DC motor The bearing portion supports the force acting in the radial direction of the inner rotor due to fluid pressure at a position substantially coincident with the axial direction of the pump rotating shaft, and wraps the boss portion and the boss portion. A sixth clearance is provided between the surrounding boss portion surrounding surfaces, a first clearance is provided between the bearing portion and the inner surface of the supported hole, and one axial direction side of the pump rotating shaft A second clearance is provided between the end of the connecting hole and the inner surface of the connecting hole, and the portions of the pump rotating shaft and the inner surface of the connecting hole that face each other via the second clearance are: The second clearance has a portion having a substantially arc shape and a portion having a flat shape, and the second clearance allows tilting of the pump rotation shaft with respect to the connection hole.

  That is, when a fluid pressure between the outer rotor and the inner rotor is applied to the inner rotor in the radial direction, a force acts in a direction in which the inner rotor is inclined in the bearing structure of the conventional inner rotor. Since it is received by the bearing portion at a position substantially coincident with the axial direction of the pump rotation shaft, the tilt of the inner rotor is suppressed.

  As a result, the friction torque between the inner rotor and the outer peripheral part thereof, and the noise and vibration that are generated due to the inclination of the inner rotor and the proper engagement cannot be obtained are suppressed.

  Further, in the electric oil pump according to one aspect of the present invention, the bearing portion is provided on a side surface portion of the pump housing located on a tip side of the pump rotating shaft so as to restrict the radial movement of the inner rotor. Configured.

  Furthermore, in the electric oil pump according to one aspect of the present invention, when assembling the pump housing provided with the driving portion and the side surface portion of the pump housing positioned on the front end side of the pump rotating shaft, the coaxiality of both is ensured. The positioning member was provided.

  That is, when assembling the pump housing provided with the drive unit and the side surface of the pump housing located on the tip end side of the pump rotating shaft, the coaxiality between the two is maintained by the positioning member.

  In addition, in the electric oil pump according to one aspect of the present invention, a tip clearance between the inner rotor and the outer rotor, an inner rotor support portion clearance between the inner rotor and the bearing portion, and a pump including the driving portion The dimension of the housing and the side surface portion of the pump housing provided with the bearing portion plus the shift amount of the central axis was set to be smaller than the body clearance between the outer rotor and the outer rotor surrounding surface surrounding the outer rotor.

  Thereby, the friction torque in the location with a large diameter is suppressed by making non-contact between the outer rotor and the outer rotor surrounding surface surrounding the outer rotor.

  Further, in the electric oil pump according to one aspect of the present invention, the inner rotor support portion clearance between the inner rotor and the bearing portion, the amount of inclination due to the rigidity of the bearing portion, the pump housing including the drive portion, and the bearing The dimension of the side surface of the pump housing provided with a central portion is less than the boss clearance between the boss extending from the inner rotor and the boss surrounding surface surrounding the boss. Set.

  Thereby, friction torque is suppressed by making non-contact between the boss portion of the inner rotor and the boss portion surrounding surface surrounding the boss portion.

  Furthermore, in the electric oil pump according to one aspect of the present invention, the center post portion of the inner rotor support portion between the inner rotor and the bearing portion, the displacement of the central axis of the pump housing including the driving portion and the side surface portion of the pump housing. The dimension including the amount was set to be smaller than the clearance between the pump rotating shaft and the rotating shaft surrounding surface surrounding the pump rotating shaft.

  That is, the central axis of the pump housing provided with the drive unit and the side surface of the pump housing is shifted to the maximum on one side, the inner rotor is shifted to the maximum on the one side with respect to the bearing unit, and the pump rotation shaft Even when the bearing portion is shifted to the one side as much as possible in design, contact between the pump rotary shaft and the rotary shaft surrounding surface surrounding the pump rotary shaft is prevented.

  Thereby, interference in the radial direction between the pump rotation shaft and the rotation shaft surrounding surface surrounding the pump rotation shaft is prevented.

  In addition, in the electric oil pump according to one aspect of the present invention, the amount of tooth tip displacement of the inner rotor due to the inclination of the bearing portion extends from the tooth tip of the inner rotor to the tooth tip surrounding surface surrounding the tooth tip. It was set to be smaller than the clearance.

  That is, even when the bearing portion is inclined by the amount of inclination due to its rigidity and the tooth tip of the inner rotor is displaced as much as possible by design, both the tooth tip of the inner rotor and both surfaces of the tooth tip surrounding surface surrounding the tooth tip are contacted simultaneously. It is prevented.

  Thereby, the friction torque at the tooth tip of the inner rotor, that is, the outer peripheral edge portion is suppressed.

  In the electric oil pump according to one aspect of the present invention, the fluid discharge port is provided in the same direction as the boss extending from the inner rotor.

  That is, since the discharge port is provided in the same direction as the boss portion extending from the inner rotor, the fluid pressure on the discharge port side of the inner rotor decreases. As a result, a differential pressure is generated between the discharge port side and the opposite side of the discharge port side, so that a force directed toward the discharge port side is applied to the inner rotor, and the surface of the inner rotor on the discharge port side The inner rotor is energized and sealed against a surface facing the surface on the discharge port side.

  Thereby, the flow of the fluid to the said boss | hub part clearance part provided in the inner side is suppressed.

  As described above, in the electric oil pump according to one aspect of the present invention, the fluid pressure between the outer rotor and the inner rotor is generated in the radial direction with respect to the inner rotor, and a force acts in a direction in which the inner rotor is inclined. The fluid pressure can be received by a bearing portion that receives pressure at a position substantially coincident with the axial direction of the pump rotation shaft, and tilting of the inner rotor can be suppressed.

  As a result, it is possible to suppress friction torque between the inner rotor and the outer rotor and the outer peripheral portion thereof, and it is possible to suppress noise and vibration that are generated due to an inclination of the inner rotor and an appropriate engagement cannot be obtained.

  Therefore, low friction and low noise can be realized with a simple configuration.

  Further, in the electric oil pump according to one aspect of the present invention, the bearing portion is provided on a side surface of the pump housing located on the tip side of the pump rotating shaft, and suppresses the radial movement of the inner rotor. It is configured as follows.

  For this reason, one side of the inner rotor can be held by the pump rotating shaft with a clearance, while the other side can be held by the bearing portion.

  Therefore, compared with the conventional case where the inner rotor is cantilevered only by the boss portion, it is possible to prevent an inadvertent inclination of the inner rotor.

  Furthermore, in the electric oil pump of one aspect of the present invention, when assembling the pump housing provided with the driving portion and the side surface portion of the pump housing positioned on the front end side of the pump rotating shaft, both of them are positioned by a positioning member. The coaxiality can be easily maintained.

  Thereby, compared with the case where the coaxiality of the pump housing and pump housing side part which are mutually assembled cannot be maintained, generation of friction torque and abnormal noise can be suppressed.

  In addition, in the electric oil pump according to one aspect of the present invention, it is possible to suppress the friction torque at a portion having a large diameter.

  In the electric oil pump according to one aspect of the present invention, the friction torque can be suppressed by making non-contact between the boss portion of the inner rotor and the boss portion surrounding surface surrounding the boss portion.

  Furthermore, in the electric oil pump according to one aspect of the present invention, the central axis of the pump housing provided with the drive unit and the side surface of the pump housing is deviated to the maximum on one side in design, and the inner rotor is located on the one side relative to the bearing unit. The pump rotation shaft and the rotary shaft surrounding surface surrounding the pump rotation shaft even when the pump rotation shaft and the bearing portion are shifted to the one side by design maximum. Can be prevented.

  Thereby, interference in the radial direction between the pump rotating shaft and the rotating shaft surrounding surface surrounding the pump rotating shaft can be prevented. For this reason, when the pump rotating shaft is supported by, for example, a ball bearing, it is possible to suppress the friction torque due to the side force of the ball bearing.

  In addition, in the electric oil pump according to one aspect of the present invention, even if the bearing portion is inclined by an amount of inclination due to its rigidity and the tooth tip of the inner rotor is displaced to the maximum by design, the tooth tip of the inner rotor And contact with both surfaces of the tooth tip surrounding surface surrounding the tooth tip can be prevented.

  Thereby, generation | occurrence | production of the strong pressing force in the tooth tip of the said inner rotor, ie, an outer periphery edge part, can be prevented, and the friction torque in the said outer periphery edge part can be suppressed.

  Further, in the electric oil pump according to one aspect of the present invention, since the discharge port is provided in the same direction as the boss portion extending from the inner rotor, the pump housing on the side where the end surface of the inner rotor and the discharge port are provided As a result of the difference in area with the contact surface of the inner rotor, the surface on the discharge port side of the inner rotor is urged to the facing surface facing the surface on the discharge port side of the inner rotor, leakage is suppressed, and a sealing effect is obtained. be able to.

  Thereby, the flow of the fluid to the said boss | hub part clearance part provided in the inner side can be blocked | prevented, the accidental leakage of the fluid can be prevented, and the volumetric efficiency of the pump can be improved.

It is explanatory drawing which shows the usage example of one embodiment of this invention. It is a figure which shows the embodiment, (a) is sectional drawing, (b) is a disassembled perspective view. It is an enlarged view of the principal part which shows the same embodiment. It is explanatory drawing which shows the comparison with the same embodiment and the past. It is explanatory drawing which shows the clearance in each place of the embodiment. It is explanatory drawing which shows the clearance in each place of the embodiment. It is explanatory drawing which shows the clearance between the shaft part of the pump rotating shaft of the embodiment, and an inner rotor. It is explanatory drawing which shows the clearance in each place of the embodiment. It is explanatory drawing which shows the effect by the discharge outlet of the embodiment. It is explanatory drawing which shows the conventional electric oil pump. It is sectional drawing which shows the principal part of the conventional electric oil pump.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing an example of use of an electric oil pump 1 according to the present embodiment. The electric oil pump 1 supplies oil for cooling electric parts such as a motor, or uses AT or CVT of an automobile. It is attached to the automatic transmission 2 or the like and used for the purpose of maintaining the hydraulic pressure that decreases when idling stops at a predetermined pressure.

  The electric oil pump 1 includes a motor unit 21 and a pump unit 22, as shown in FIG. A brushless DC motor 24 as a drive unit is provided in the casing 23 of the motor unit 21. The brushless DC motor 24 includes a stator 25 and a rotor 26 disposed in the stator 25, and a pump rotating shaft 27 that outputs a rotational force is fixed to the rotor 26.

  The pump rotating shaft 27 has a portion extending from one end of the rotor 26 rotatably supported by the casing 23 via a first ball bearing 31, and a portion extending from the other end of the rotor 26. Is rotatably supported by a pump body 33 as a pump housing in the pump portion 22 via a second ball bearing 32.

  The other end of the pump rotating shaft 27 is set to a length that extends from the second ball bearing 32, and is configured to extend toward the pump portion 22 and supply driving force.

  The pump portion 22 is configured such that the pump body 33 is fixed to the casing 23, and a through hole 41 is formed in the central portion of the pump body 33. The through hole 41 has a small diameter at the upper end and a large diameter at the lower end.

  As shown in FIG. 3, bolt holes 51,... Are provided at a plurality of locations on the lower surface of the pump body 33, and the bolts 51,. A large-diameter portion 52 having a slightly larger diameter than the hole 51 is formed. A base end portion of a collar 53 as a cylindrical positioning member is press-fitted into the large-diameter portion 52, and the collar 53 is configured such that a distal end portion thereof protrudes from the pump body 33.

  A pump cover 61 serving as a side surface of the pump housing is fixed to the lower surface of the pump body 33, and the pump cover 61 has a position corresponding to each bolt hole 51 of the pump body 33. Bolt insertion holes 62 are formed. Among the bolt insertion holes 62,..., The bolt insertion holes 62 corresponding to the collar 53 are formed in a size that allows the collar 53 to be fitted therein.

  Accordingly, when the pump cover 61 is assembled to the pump body 33, the collar 53 protruding from the pump body 33 is fitted into the bolt insertion hole 62 of the pump cover 61, whereby the pump cover 61 The center position 61a of the pump body 33 and the center position 33a of the pump body 33 are made to coincide with each other, so that the same axis can be secured.

  Here, although the center position 61a of the pump cover 61 and the center axis of a bearing portion 132 provided on the pump cover 61, which will be described later, do not exactly coincide with each other, in the present embodiment, for convenience of explanation, the pump The description will be made assuming that the center position 61a of the cover 61 and the center axis of the bearing portion 132 provided on the pump cover 61 coincide with each other.

  Similarly, the center position 33a of the pump body 33 and the center axis of the pump rotation shaft 27 of the brushless DC motor 24 provided in the pump body 33 do not exactly coincide with each other. For convenience, the description will be made assuming that the center position 33a of the pump body 33 and the center axis 27a of the pump rotation shaft 27 of the brushless DC motor 24 provided in the pump body 33 coincide with each other.

  At this time, the length of the collar 53 is set so that the tip of the collar 53 does not protrude from the bolt insertion hole 62 of the pump cover 61, so that tightening by the bolts 71,. It is configured.

  The pump body 33 has the pump cover 61 attached to the lower surface thereof, and the through hole 41 is closed by the pump cover 61, whereby a pump chamber 81 is formed by a large diameter portion on the lower end side of the through hole 41. Has been.

  The pump body 33 is provided with a suction port 91 that opens on the top surface 81a of the pump chamber 81 on the right side in the figure, and the suction port 91 communicates with a suction port 92 to which oil is supplied. ing. A discharge port 93 that opens to the top surface 81a of the pump chamber 81 is provided on the left side of the pump body 33 in the drawing, and the discharge port 93 communicates with a discharge port 94 that discharges oil. Yes.

  An inner rotor 102 (internal gear) constituting an internal gear type gear pump 101 is rotatably accommodated in the pump chamber 81, and an outer rotor 103 (external gear) rotates on the outer periphery of the inner rotor 102. It is freely housed.

  A boss portion 111 extends upward from the upper end surface of the inner rotor 102, and the boss portion 111 is inserted into a small-diameter hole 112 configured by a small-diameter portion of the through hole 41.

  Accordingly, the small-diameter hole 112 and the discharge port 93 are formed upward from the top surface 81a of the pump chamber 81, and are in the same direction as the extending direction of the boss 111 extending from the inner rotor 102. The discharge port 93 communicated with the discharge port 94 is provided.

  A connecting hole 121 is formed in the boss portion 111, and a lower end portion of the pump rotating shaft 27 is inserted into the connecting hole 121. A predetermined clearance is maintained between the lower end portion of the pump rotary shaft 27 and the connecting hole 121 while preventing idling of each other, and the pump rotary shaft 27 is allowed to tilt slightly.

  As a result, the rotational force from the brushless DC motor 24 is transmitted to the inner rotor 102. The brushless DC motor 24 rotates the inner rotor 102 and rotates the inner rotor 102. When the outer rotor 103 rotates, the volume between the inner rotor 102 and the outer rotor 103 is changed while rotating, and the oil sucked from the suction port 91 is communicated with the discharge port 94 from the discharge port 93. It is comprised so that it can discharge.

  A supported hole 131 that opens downward is provided in the lower end surface of the inner rotor 102, and a bearing portion 132 that is inserted into the supported hole 131 is formed integrally with the pump cover 61. .

  As shown in FIGS. 3 and 4, the bearing portion 132 is disposed on the distal end side of the pump rotating shaft 27, and the hydraulic reaction force F of the hydraulic pressure between the inner rotor 102 and the outer rotor 103 is the inner rotor 102. The hydraulic reaction force F is received at a position substantially coincident with the axial direction of the pump rotating shaft 27 when acting in the radial direction, so that the radial movement of the inner rotor 102 can be restricted. ing.

  In the pump part 22 configured as described above, as shown in FIG. 5, a tip clearance 201 between the inner rotor 102 and the outer rotor 103, an inner rotor support part clearance 202 between the inner rotor 102 and the bearing part 132, The dimensions of the pump body 33 and the pump cover 61 plus the shift amounts of the central axes (33a, 61a) are the body of the outer rotor 103 and the outer rotor surrounding surface 203 of the inner surface of the pump chamber 81 surrounding the outer rotor 103. It is set to be smaller than the clearance 204.

  Further, the inner rotor support portion clearance 202 between the inner rotor 102 and the bearing portion 132, the amount of inclination due to the rigidity of the bearing portion 132, and the shift of the central axis (33a, 61a) of the pump body 33 and the pump cover 61. The dimension including the amount is smaller than the boss portion clearance 212 between the boss portion 111 extending from the inner rotor 102 and the boss portion surrounding surface 211 of the inner surface of the small diameter hole 112 surrounding the boss portion 111. Is set to

  Further, as shown in FIG. 6, the inner rotor support portion clearance 202 between the inner rotor 102 and the bearing portion 132, the displacement amount of the central axis (33 a, 61 a) of the pump body 33 and the pump cover 61, The dimension obtained by adding the axial displacement of the pump rotating shaft 27 and the bearing portion 132 is smaller than the clearance 232 between the rotating shaft surrounding surface 231 of the connecting hole 121 surrounding the pump rotating shaft 27 and the pump rotating shaft 27. It is set to be.

  In FIG. 6, the axial misalignment between the bolt hole 51 of the pump body 33 and the corresponding hole of the bolt insertion hole 62 of the pump cover 61 is the center axis of the pump body 33 and the pump cover 61 ( 27a, 61a), and the gap between the outer periphery of the pump rotary shaft 27 and the pump body 33 is similarly set to the axial displacement of the pump rotary shaft 27 and the bearing portion 132. It is shown as being equivalent to a quantity.

  Further, as shown in FIG. 7, the pump rotation shaft 27 and the connection hole 121 surrounding the pump rotation shaft 27 have a clearance 232 between the inner surface and the rotation shaft surrounding surface 231. The opposing part of the shaft 27 and the rotary shaft surrounding surface 231 has two surfaces of the shapes 27c and 231c that form a plane with each other, while a part thereof has a substantially arcuate shape 27b and 231b.

  For this reason, when the pump rotation shaft 27 is rotated, line contact is made between the shape 27c forming the plane of the pump rotation shaft 27 and the shape 231c forming the plane of the 231. The clearance as the clearance 232 is always maintained.

  Further, as shown in FIG. 8, the amount of tooth tip displacement of the inner rotor 102 due to the inclination of the bearing portion 132 is from the tooth tip of the inner rotor 102 to the tooth tip surrounding surface 242 of the inner surface of the outer rotor 103 surrounding the tooth tip. It is set to be smaller than the clearance.

  When the hydraulic reaction force F between the outer rotor 103 and the inner rotor 102 of the internal gear type gear pump 101 is applied to the inner rotor 102 in the radial direction in the present embodiment according to the above configuration, FIG. As shown, the force acts in the direction in which the inner rotor 102 is tilted, but the hydraulic reaction force F is received by the bearing portion 132 that receives pressure at a position substantially coincident with the axial direction of the pump rotating shaft 27, Tilt of the inner rotor 102 can be suppressed.

  Accordingly, it is possible to suppress the friction torque 501 between the inner rotor 102 and the outer rotor 103 and the outer peripheral portion thereof, and it is possible to suppress noise and vibration that are generated due to the inclination of the inner rotor 102 and an appropriate meshing cannot be obtained. .

  Therefore, low friction and low noise can be realized with a simple configuration.

  When the pump cover 61 located on the distal end side of the pump rotating shaft 27 is assembled to the pump body 33 provided with the brushless DC motor 24, the coaxiality between the collars 53 and 53 is easily maintained. be able to.

  Thereby, compared with the case where the coaxiality of the pump body 33 and the pump cover 61 assembled to each other cannot be maintained, generation of the friction torque 501 and the collision sound 502 can be suppressed.

  Further, as shown in FIG. 5, the pump body 33 provided with the brushless DC motor 24 and the central axis (33a, 61a) of the pump cover 61 provided with the bearing portion 132 are designed to be maximum on one side. Even when the inner rotor 102 is deviated from the bearing portion 132 to the one side by the maximum design and the inner rotor 102 is deviated from the outer rotor 103 to the one side by design. The outer rotor 103 and the outer rotor surrounding surface 203 surrounding the outer rotor 103 and the contact 512 can be reliably prevented.

  Thereby, the friction torque in a location with a large diameter can be suppressed.

  Further, the pump body 33 is shifted from the central axis (61a) of the pump cover 61 provided with the bearing portion 132 to the maximum one side by design, and the bearing portion 132 moves to the one side due to the rigidity of the bearing portion 132. Even when the inner rotor 102 is tilted to the maximum in design and the inner rotor 102 is shifted from the bearing portion 132 to the one side to the maximum in design, the boss 111 extending from the inner rotor 102 and the boss 111 are surrounded. The contact 511 between the boss surrounding surfaces 211 can be reliably prevented.

  Thereby, the friction torque in a location with a large diameter can be suppressed.

  Furthermore, as shown in FIG. 6, the central axis (33a, 61a) between the pump body 33 and the pump cover 61 is shifted to the maximum on one side in design, and the inner rotor 102 is moved relative to the bearing portion 132. Even when the maximum deviation in design to the one side and the pump rotation shaft 27 and the bearing portion 132 are maximum deviation in design to the one side, the pump rotation shaft 27 and the pump rotation shaft 27 are moved. Contact with the surrounding rotary shaft surrounding surface 231 can be prevented, and a predetermined clearance can be maintained.

  Thereby, since the interference in the radial direction of the pump rotating shaft 27 can be prevented, the friction torque due to the side force from the ball bearings 31 and 32 supporting the pump rotating shaft 27 can be suppressed.

  Further, as shown in FIG. 8, even if the bearing portion 132 is inclined by an amount of inclination due to its rigidity and the tooth tip of the inner rotor 102 is displaced as much as possible in design, the tooth tip of the inner rotor 102 and the tooth tip are concerned. It is possible to prevent simultaneous interference on both sides with the tooth tip surrounding surface 242 surrounding the tip.

  As a result, it is possible to prevent generation of strong pressing force at the tooth tip of the inner rotor 102, that is, the outer peripheral edge portion 521, and to suppress friction torque at the outer peripheral edge portion 521.

  As shown in FIG. 9, since the discharge port 93 communicating with the discharge port 94 is provided in the same direction as the boss portion 111 extending from the inner rotor 102, the end surface of the inner rotor 102 and the A difference arises in the area with the contact surface of the pump body 33 on the side where the discharge port is provided.

  Thereby, since the force f1 toward the discharge port 94 is applied to the inner rotor 102, the end surface on the discharge port 93 side that communicates with the discharge port 94 of the inner rotor 102 faces the end surface. It is urged by the top surface 81a of the pump chamber 81 to exhibit a sealing effect.

  Thereby, the flow of oil to the clearance between the outer peripheral surface of the boss 111 provided on the inside and the small-diameter hole 112 of the through hole 41 can be suppressed, and the oil does not pass through the through hole 41. Since leakage to the prepared motor unit 21 side can be suppressed, the volumetric efficiency of the pump can be improved.

DESCRIPTION OF SYMBOLS 1 Electric gear pump 24 Brushless DC motor 27 Pump rotation shaft 33 Pump body 53 Collar 61 Pump cover 94 Discharge port 102 Inner rotor 103 Outer rotor 111 Outer rotor 111 Boss part 132 Bearing part 201 Tip clearance 202 Inner rotor support part clearance 203 Outer rotor surrounding surface 204 Body clearance 211 Boss surrounding surface 212 Boss clearance 231 Rotating shaft surrounding surface 232 Clearance 242 Tooth tip surrounding surface F Hydraulic reaction force

Claims (16)

A drive unit and a pump unit;
The pump part is
An inner rotor rotated by a pump rotation shaft from the drive unit;
An outer rotor provided outside the inner rotor;
A pump housing in which the inner rotor and the outer rotor are housed;
With
An electric oil pump characterized in that a bearing portion is provided in the pump housing for supporting a force acting in a radial direction of the inner rotor by a fluid pressure at a position substantially coincident with an axial direction of the pump rotating shaft.   The electric oil pump according to claim 1, wherein a first clearance is provided between the inner rotor and the bearing portion. A fourth clearance between the inner rotor and the outer rotor;
The first clearance between the inner rotor and the bearing portion;
The dimension which added the deviation | shift amount of the center axis | shaft of the said drive part and the said bearing part,
The electric oil pump according to claim 2, wherein the electric oil pump is set to be smaller than a fifth clearance between the outer rotor and an outer rotor surrounding surface surrounding the outer rotor. In an electric oil pump comprising an inner rotor rotated by a pump rotation shaft from a drive unit and an outer rotor provided outside the inner rotor,
A bearing portion is provided that supports a force acting in the radial direction of the inner rotor due to fluid pressure at a position that substantially matches the axial direction of the pump rotation shaft,
A first clearance between the inner rotor and the bearing portion;
The amount of inclination due to the rigidity of the bearing part,
The dimension which added the deviation | shift amount of the center axis | shaft of the said drive part and the said bearing part,
An electric oil pump configured to be smaller than a sixth clearance between a boss portion extending from the inner rotor and a boss portion surrounding surface surrounding the boss portion. A fourth clearance between the inner rotor and the outer rotor;
A first clearance between the inner rotor and the bearing portion;
The dimension which added the deviation | shift amount of the center axis | shaft of the said drive part and the said bearing part,
The electric oil pump according to claim 4, wherein the electric oil pump is set to be smaller than a fifth clearance between the outer rotor and an outer rotor surrounding surface surrounding the outer rotor. A first clearance between the inner rotor and the bearing portion;
The amount of inclination due to the rigidity of the bearing part,
The dimension which added the deviation | shift amount of the center axis | shaft of the said drive part and the said bearing part,
The electric oil pump according to claim 5, wherein the electric oil pump is set to be smaller than a sixth clearance between a boss portion extending from the inner rotor and a boss portion surrounding surface surrounding the boss portion.   The said bearing part is provided in the pump cover located in the front end side of the said pump rotating shaft, It comprised so that the movement of the radial direction of the said inner rotor might be controlled, The one of Claim 1 to 6 characterized by the above-mentioned. The electric oil pump described in 1.   The electric oil pump according to any one of claims 1 to 7, wherein a discharge port for the fluid is provided in the same direction as a boss portion extending from the inner rotor. The inner rotor has a supported hole opened on one side in the axial direction,
The bearing portion is inserted into the supported hole,
The electric oil according to any one of claims 1 to 8, wherein an inclined surface that is located radially outward toward the one axial side is provided at an opening edge portion on one axial side of the supported hole. pump. A drive unit having a pump rotation shaft;
An inner rotor having a supported hole which is connected to the pump rotation shaft and rotates on one side in the axial direction of the pump rotation shaft, and which is open on the one side in the axial direction;
An outer rotor that surrounds the inner rotor and rotates with the rotation of the inner rotor;
A boss part that extends from the inner rotor to the other side in the axial direction, has a connection hole into which an end part on the one side in the axial direction of the pump rotation shaft is inserted, and transmits the rotation of the pump rotation shaft;
A bearing portion inserted into the supported hole;
With
The drive unit is a brushless DC motor,
The bearing portion supports the force acting in the radial direction of the inner rotor due to fluid pressure at a position substantially coincident with the axial direction of the pump rotation shaft,
Between the boss part and the boss part surrounding surface surrounding the boss part, a sixth clearance is provided,
A first clearance is provided between the bearing portion and the inner surface of the supported hole,
A second clearance is provided between the axial one end of the pump rotation shaft and the inner surface of the connection hole,
In the pump rotating shaft and the inner surface of the connecting hole, the portions facing each other through the second clearance have a portion having a substantially arc shape and a portion having a flat shape,
The electric oil pump according to claim 2, wherein the second clearance allows tilting of the pump rotation shaft with respect to the connection hole.   The electric oil pump according to claim 10, wherein a third clearance is provided between a tooth tip of the inner rotor and a tooth tip surrounding surface surrounding the tooth tip.   The electric oil pump according to claim 11, wherein an amount of tooth tip displacement of the inner rotor due to the inclination of the bearing portion is set to be smaller than the third clearance. A fourth clearance between the inner rotor and the outer rotor;
The first clearance;
The amount of deviation of the central axis of the drive part and the bearing part,
The dimension plus
The electric oil pump according to any one of claims 10 to 12, wherein the electric oil pump is set to be smaller than a fifth clearance between the outer rotor and an outer rotor surrounding surface that surrounds the outer rotor. The first clearance;
The amount of inclination due to the rigidity of the bearing part,
The amount of deviation of the central axis of the drive part and the bearing part,
The dimension plus
The electric oil pump according to any one of claims 10 to 13, wherein the electric oil pump is set to be smaller than the sixth clearance.   The electric oil according to any one of claims 10 to 14, wherein an opening edge on one side in the axial direction of the supported hole is provided with an inclined surface positioned radially outward as it goes toward the one side in the axial direction. pump.   The electric oil pump according to any one of claims 1 to 15, wherein a gap is provided between an axial direction of the pump rotation shaft and the bearing portion.

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