JP2013150398A - Electric pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric pump that suppresses local loading on a shaft support bore.SOLUTION: The electric pump includes: a pump housing 1 having a shaft support bore 1a for rotatable journaling of an intermediate portion of a rotary shaft 7 having a pump rotor 8 on one end side and a motor rotor 9 on the other end side, and a pump chamber recessed portion 1b constituting part of a pump chamber P on the one end side of the shaft support bore 1a; and a stator case 3 fixed to the other end side of the pump housing 1, fixedly storing a motor stator 6 inside, and storing the motor rotor 9 within the motor stator 6. A rotary member comprising the rotary shaft 7, the pump rotor 8 and the motor rotor 9 is set to have the same weight moment on the side of the pump rotor 8 and on the side of the motor rotor 9 divided at an axial middle of the shaft support bore 1a.

Description

  The present invention relates to an electric pump that sucks and discharges fluid such as oil.

  Conventionally, as an electric pump, there exist some which were indicated by patent documents 1, for example. The electric pump includes a pump housing having a shaft support hole that rotatably supports an intermediate portion of a rotating shaft, a motor stator that is fixed to the pump housing, and an end of the rotating shaft that is provided inside the motor stator. And a stator case that accommodates the motor rotor provided in the section. On one end side of the pump housing is formed a pump chamber constituting portion that constitutes a part of the pump chamber, and a pump action portion is provided on one end side of the rotating shaft that protrudes from the shaft support hole in the pump chamber constituting portion. Yes.

Japanese Patent No. 4042050

  By the way, the rotating shaft in the electric pump as described above is provided with a pump action portion on one end side, a motor rotor on the other end side, and only the intermediate portion is pivotally supported by the shaft support hole. In such a configuration, there is a risk that a plowing motion is generated on each of the pump action portion side and the motor rotor side, and a load is locally applied to any end portion of the shaft support hole in the axial direction. This causes, for example, a part of the shaft support hole to wear, leading to an early decline in pump performance and quietness.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide an electric pump capable of suppressing a load from being locally applied to a shaft support hole.

  According to the first aspect of the present invention, a rotating shaft, a pump action portion provided on one end side of the rotating shaft, a motor rotor provided on the other end side of the rotating shaft, and an intermediate portion of the rotating shaft are rotated. A pump housing having a shaft support hole that is pivotally supported and a pump chamber constituting part of the pump chamber on one end side of the shaft support hole, and fixed to the other end side of the pump housing, An electric pump including a motor stator that is housed and fixed and a stator case that houses the motor rotor inside the motor stator, and includes a motor rotor and a pump rotor provided as the pump operating portion and the motor rotor. The weight moment on the pump rotor side and the weight moment on the motor rotor side are set to coincide with each other from the axial center of the shaft support hole in the rotating member. It is the gist of.

  According to this configuration, the weight moment on the pump rotor side and the weight moment on the motor rotor side coincide with each other from the axial center of the shaft support hole in the rotary member composed of the rotary shaft and the pump rotor provided as the pump action unit. Therefore, it is possible to prevent a load from being locally applied to any end portion in the axial direction of the shaft support hole. Therefore, for example, the wear resistance of the shaft support hole is increased, and high pump performance and high silence can be maintained for a long time. In addition, even when external vibration is applied when the electric pump is not operating, wear of the shaft support hole can be suppressed, and as a result, high pump performance and high quietness when the electric pump is operated can be maintained for a long time. Can be maintained.

  According to a second aspect of the present invention, in the electric pump according to the first aspect, a suction port and a discharge port are provided on the one end side of the pump chamber, and the motor stator has an axial center at the one end. The gist is that the motor rotor is provided at a position displaced toward the other end side from the axial center.

  According to this configuration, the motor stator is provided such that the axial center thereof is displaced to the other end side from the axial center of the motor rotor. Therefore, the motor rotor and the pump rotor are always attached to the other end side. It becomes a biased state, and it can be made hard to vibrate compared with the state which is not biased. In addition, a suction port and a discharge port are provided on one end side in the pump chamber, and the biasing direction described above is the same as the direction in which the pump rotor is biased by the oil on the discharge port side (one end side), and the other end The energizing effect to the side becomes large. Therefore, the wear of the shaft support hole can be further suppressed, and as a result, the effect of maintaining high pump performance and high quietness for a long time when the electric pump is operated can be further improved.

A third aspect of the present invention is summarized in that, in the electric pump according to the first or second aspect, the motor rotor is a flat rotor having a diameter larger than an axial length.
According to this configuration, since the motor rotor is a flat rotor whose diameter is larger than the axial length, the overall axial length of the electric pump can be shortened, and the maximum distance from the shaft support hole can be reduced. It is possible to reduce the displacement in the radial direction during rotation (amplitude of the plowing motion), and thus, for example, high silence can be obtained.

  According to a fourth aspect of the present invention, in the electric pump according to any one of the first to third aspects, the rotor core of the motor rotor has an axial length of a radially inner portion into which the rotary shaft is press-fitted. The gist is that it is formed shorter than the axial length of the outer portion in the direction.

  According to this configuration, the rotor core of the motor rotor is formed such that the axial length of the radially inner portion into which the rotating shaft is press-fitted is shorter than the axial length of the radially outer portion, so that the weight of the rotor core is reduced. The weight moment on the motor rotor side can be reduced and can be set to easily match the weight moment on the pump rotor side.

  According to a fifth aspect of the present invention, in the electric pump according to the fourth aspect of the present invention, the axial length of the radially inner portion of the rotor core is formed to be short on the opposite side of the pump housing. The gist is that the side annular recess is formed.

  According to this configuration, the axial length of the radially inner portion of the rotor core is shortened so that an anti-pump side annular recess is formed on the opposite side of the pump housing. The weight moment on the motor rotor side can be made smaller than that in which the pump side annular recess is formed. Therefore, the weight moment on the motor rotor side and the weight moment on the pump rotor side can be set so as to easily match.

  According to a sixth aspect of the present invention, in the electric pump according to the fourth or fifth aspect, the axial length of the radially inner portion of the rotor core is shortened so that the pump housing side is closer to the pump housing side. An annular recess is formed, and in the pump-side annular recess, the pump chamber side and the accommodation chamber side in which the motor stator is accommodated are defined in a state of being externally fitted to the rotary shaft while being held by the pump housing. The gist is that at least a part of the oil seal is arranged.

  According to this configuration, the rotor core is formed with the pump-side annular recess on the pump housing side by forming the radially inner portion with a short axial length. In the pump-side annular recess, at least a part of an oil seal that divides the pump chamber side and the housing chamber side in which the motor stator is housed in a state of being fitted to the rotating shaft while being held by the pump housing is disposed. Therefore, the entire axial length of the electric pump can be shortened as compared with the case where the electric pump is not disposed in the pump-side annular recess.

  ADVANTAGE OF THE INVENTION According to this invention, the electric pump which can suppress that a load is locally applied to a shaft support hole can be provided.

Sectional drawing of the electric pump in one Embodiment. The disassembled perspective view of the electric pump in one Embodiment. The perspective view of the electric pump in one Embodiment. The perspective view of the electric pump in one Embodiment. Sectional drawing of the electric pump in another example. (A)-(c) Partial sectional drawing of the electric pump in another example.

Hereinafter, an embodiment in which the present invention is embodied as an electric pump for circulating vehicle oil will be described with reference to FIGS.
As shown in FIG. 1, the electric pump includes a pump housing 1, a pump end plate 2, a stator case 3, a circuit case member 4, and a heat sink cover 5. In addition, the motor stator 6, the rotating shaft 7, the pump rotor 8 as a pump action unit, the motor rotor 9, and circuit components to be described later are included therein.

  The pump housing 1 is made of metal, and is specifically made of an aluminum alloy that is a nonmagnetic metal. The pump housing 1 is formed in a substantially cylindrical shape, and has a shaft support hole 1a for pivotally supporting an intermediate portion of the rotating shaft 7 at the center of the shaft. In addition, the rotating shaft 7 of this embodiment consists of stainless steel which is a nonmagnetic metal. In addition, a pump chamber recess 1b as a pump chamber constituting portion constituting a part of the pump chamber P is formed on one end side (left side in FIG. 1) of the pump housing 1. The pump chamber recess 1b is formed in a circular shape with a shaft center shifted from the shaft center of the pump housing 1 (shaft support hole 1a) when viewed from the axial direction. Further, a pump housing side stamping cylinder portion 1c having a small outer diameter and projecting in a cylindrical shape is formed on the other end side (right side in FIG. 1) of the pump housing 1. In addition, a small cylindrical portion 1d having a smaller outer diameter and projecting into a cylindrical shape is formed at the end of the pump housing side stamping cylindrical portion 1c, and at the other end of the pump housing 1 including the small cylindrical portion 1d, An oil seal accommodating portion 1e that can accommodate and hold the oil seal 11 by increasing the diameter from the shaft support hole 1a is formed. The oil seal 11 is fitted in the oil seal housing portion 1e and is fitted on the rotary shaft 7 while being externally fitted to the pump chamber P side (left side in FIG. 1) and the housing chamber S side in which the motor stator 6 is housed (see FIG. 1 and the right side). Further, as shown in FIG. 2, a pair of fixed protrusions 1f protruding outward in the radial direction are formed at the other end of the outer periphery of the pump housing 1, and these fixed protrusions 1f are respectively penetrated in the axial direction. A fixing through hole 1g is formed. A pump end plate 2 is fixed to one end side of the pump housing 1.

  The pump end plate 2 is made of metal, specifically, an aluminum alloy that is a nonmagnetic metal. As shown in FIG. 1, the pump end plate 2 substantially closes the pump chamber recess 1b and constitutes the pump chamber P together with the pump chamber recess 1b. Further, as shown in FIGS. 2 and 3, the pump end plate 2 is formed with a suction port 2a and a discharge port 2b that communicate the outside with the inside of the pump chamber P. As shown in FIG. 2, a female screw hole 2c is formed at a position corresponding to the fixing through hole 1g of the pump end plate 2, and the pump end plate 2 is connected to the pump housing 1 by a through bolt 12 described later. Fixed. At this time, a seal ring 13 is sandwiched between the pump housing 1 and the pump end plate 2 to ensure the sealing performance inside and outside the (pump chamber P). In the pump chamber P, a pump rotor 8 is provided on one end side of the rotary shaft 7.

  The pump rotor 8 of this embodiment is of an internal gear type, and includes an outer rotor 8a having n teeth (n is a natural number of 3 or more) and an inner rotor 8b having n-1 teeth. The one end side of the rotating shaft 7 is press-fitted and fixed to the inner rotor 8b.

A stator case 3 is fixed to the other end side of the pump housing 1.
The stator case 3 is made of metal, and as shown in FIG. 1, a motor stator 6 is accommodated and fixed therein, and a motor rotor provided on the other end side of the rotating shaft 7 inside the motor stator 6. 9 is accommodated. More specifically, the stator case 3 is made of a metal plate, and has a large cylindrical portion 3a to which the motor stator 6 is fixed (press-fitted) on its inner periphery, and a disk portion 3b extending radially inward from one end of the large cylindrical portion 3a. And a stator case side stamping cylinder part 3c extending from the inner edge of the disk part 3b to the other end side in the axial direction and having the pump housing side stamping cylinder part 1c fitted on the inner peripheral surface thereof. The stator case 3 is preferably formed integrally by pressing. The stator case 3 is fixed to the pump housing 1 by a through bolt 12 described later in a state in which the pump housing side stamping cylinder portion 1c is stamped and fitted to the stator case side stamping cylinder portion 3c. At this time, a seal ring 14 is sandwiched between the pump housing 1 and the stator case 3 (disk portion 3b) to ensure the inside and outside sealing properties.

  The motor stator 6 is a stator that constitutes an inner rotor type brushless motor together with the motor rotor 9, and a winding 6b is wound around a stator core 6a (its teeth). Further, here, the diameter of the stamping fitting portion of the present embodiment described above (that is, the outer diameter of the pump housing side stamping cylinder part 1c and the inner diameter of the stator case side stamping cylinder part 3c) is larger than the inner diameter of the motor stator 6. Is set. As shown in FIGS. 1 and 2, the motor rotor 9 includes a plurality of magnets 16 (one embedded) in the circumferential direction of the rotor core 15 to form magnet magnetic pole portions, and each magnet magnetic pole. The core part 15a (see FIG. 2) of the rotor core 15 between the parts is a continuous pole type rotor configured to function as the other magnetic pole. The rotor core 15 of the present embodiment is a laminated core formed by laminating core sheets. Further, the motor rotor 9 of the present embodiment is a flat rotor whose diameter is larger than the axial length.

  Here, the rotating member composed of the rotating shaft 7, the pump rotor 8, and the motor rotor 9 is composed of the weight moment on the pump rotor 8 side from the axial center of the shaft supporting hole 1a and the axial direction of the shaft supporting hole 1a. The weight moment on the motor rotor 9 side from the center is set to coincide. The weight moment is a value determined by the weight of the pump rotor 8 and the motor rotor 9, the distance from the axial center of the shaft support hole 1a, and the like.

  The motor stator 6 is provided such that the axial center thereof is slightly shifted in the axial direction from the axial center of the motor rotor 9. The motor stator 6 according to the present embodiment is provided such that its axial center is displaced to the other end side (right side in FIG. 1) from the axial center of the motor rotor 9. Thereby, the motor rotor 9 and the pump rotor 8 are always urged to the other end side (right side in FIG. 1). The pump rotor 8 is brought into sliding contact with the bottom surface (the other end side end surface) of the pump chamber recess 1b by the biasing force. The biasing direction is opposite to the discharge port 2b that is an oil inlet / outlet provided on one end side in the pump chamber P, and the pump rotor 8 is biased by the oil on the discharge port 2b side. It becomes the same, and the urging effect to the other end side becomes large.

  A circuit case member 4 is fixed to the opening on the other end side of the stator case 3 (large cylinder portion 3a). Specifically, a flange portion 3d extending outward in the radial direction is formed in the opening on the other end side of the stator case 3 (large cylinder portion 3a), and the flange portion 3d has an axial direction as shown in FIG. A plurality of caulking pieces 3e that extend and have a pair of arms at their tips (only one is shown in FIG. 2) are formed. On the other hand, the circuit case member 4 is made of resin, and as shown in FIG. 1, an internal fitting cylindrical portion 4 a that can be fitted in the opening on the other end side of the stator case 3 (large cylindrical portion 3 a), and its internal fitting. A flange contact plate portion 4b extending from the other end side (right side in FIG. 1) of the cylindrical portion 4a to the outside along the flange portion 3d (in the direction orthogonal to the axis) and contacting the end surface of the flange portion 3d; Have Further, the circuit case member 4 of the present embodiment includes an extended portion 4c extending in the direction perpendicular to the axis (downward in FIG. 1) from the flange contact plate portion 4b, and an axial direction from the extended portion 4c. A connector portion 4d extending in a cylindrical shape is provided on one end side (left side in FIG. 1). One end of the connection terminal 17 embedded in the extended portion 4c is led out in the connector portion 4d. As shown in FIGS. 2 and 4, the caulking piece 3e is caulked at a position corresponding to the caulking piece 3e on the outer edge of the circuit case member 4 (flange contact plate portion 4b) (a pair of arms is attached). A caulking portion 4e that is held by the caulking piece 3e is formed. In the present embodiment, the caulking piece 3e and the caulking portion 4e form a holding structure that disables relative movement between the stator case 3 and the circuit case member 4. This holding structure fixes the stator case 3 and the circuit case member 4, but is a temporary holding structure as an electric pump, and is finally firmly fixed by a through bolt 12 described later.

  Further, as shown in FIGS. 1 and 2, the circuit case member 4 has an inwardly extending portion 4f extending inward (in the direction perpendicular to the axis) from the other end side (right side in FIG. 1) of the internal fitting cylindrical portion 4a. And a plurality of lead-out holding grooves 4g serving as lead-out holding portions for holding the coil connection end portion 6c of the motor stator 6 (winding 6b) and leading it to the other end side. Has been.

  A circuit board 23 on which various circuit components (such as a capacitor 21 and a power transistor 22) are mounted is fixed to the other end side (right side in FIG. 1) of the circuit case member 4. The circuit board 23 is formed with a connection hole through which the coil connection end 6c led out from the lead-out holding groove 4g and the other end of the connection terminal 17 can be inserted, and the coil connection end 6c and the connection terminal 17 are The circuit case member 4 is inserted into the connection hole and connected to the circuit board 23 in a state of being fixed to the stator case 3 (by the temporary holding structure).

  As shown in FIGS. 1 and 2, a heat sink cover 5 is fixed to the circuit case member 4 so as to sandwich the circuit case member 4 with the stator case 3. The heat sink cover 5 is made of metal, and as shown in FIG. 1, a circuit accommodating recess 5a for accommodating the circuit components (capacitor 21, power transistor 22, etc.) is provided on one end side (stator case 3 side). Have. The circuit accommodating recess 5a of the present embodiment is capable of accommodating a large recess 5b deep in the axial direction and a small (thin) circuit component such as the power transistor 22 so as to accommodate a large circuit component such as the capacitor 21. It has the small recessed part 5c shallow in the said axial direction. The power transistor 22 is for switching control of the current supplied to the motor stator 6 (winding 6b), and is a bottom surface (one end side end surface) of the small recess 5c via a silicone rubber 24 which is an elastic member. ).

  Further, as shown in FIGS. 1 and 2, a heat radiating fin portion 5 d protruding in the axial direction is formed on the back surface (the other end side end surface) of the small recess 5 c in the heat sink cover 5. As shown in FIG. 1, the heat dissipating fin portion 5 d of the present embodiment is formed so as to protrude within a range that does not protrude from the other end side (right side) end surface of the large concave portion 5 b. Further, as shown in FIG. 2, at the outer edge of the heat sink cover 5, the pair corresponding to the fixing through hole 1g and the female screw hole 2c protrudes outward in the direction perpendicular to the axis (only one in FIG. 2). The fixing protrusions 5e are formed, and the fixing protrusions 5e are respectively formed with fixing through holes 5f penetrating in the axial direction. The heat sink cover 5 sandwiches the circuit case member 4 between the stator case 3 and through bolts 12 that pass through the fixing through holes 5f and the fixing through holes 1g and are screwed into the female screw holes 2c. Fixed to.

Next, the operation (operation) of the above embodiment will be described.
When a current (three-phase drive current) is supplied from an external power source (not shown) to the winding 6b of the motor stator 6 via the connection terminal 17 of the connector portion 4d and the circuit components of the circuit board 23, a rotating magnetic field is generated in the motor stator 6. Based on the generated rotating magnetic field, the rotating member including the motor rotor 9, the rotating shaft 7, and the pump rotor 8 is integrally rotated. Then, as the pump rotor 8 rotates, oil is sucked from the suction port 2a and oil is discharged from the discharge port 2b.

Next, the characteristic effects of the above embodiment will be described below.
(1) The rotating member composed of the rotating shaft 7, the pump rotor 8, and the motor rotor 9 has a weight moment on the pump rotor 8 side from the axial center of the shaft support hole 1a and a motor rotor 9 side from the axial center of the shaft support hole 1a. The weight moment is set so as to match. Therefore, it is possible to suppress a load from being locally applied to any end portion in the axial direction of the shaft support hole 1a. Therefore, for example, the wear resistance of the shaft support hole 1a is increased, and high pump performance and high silence can be maintained for a long time. In addition, even when vibration is applied from the outside when the electric pump is not operating, the wear of the shaft support hole 1a can be suppressed, and as a result, high pump performance and high silence when the electric pump is operated are prolonged. It becomes possible to maintain time.

  (2) Since the motor stator 6 is provided such that its axial center is displaced to the other end side (right side in FIG. 1) from the axial center of the motor rotor 9, the motor rotor 9 and the pump rotor 8. Is always biased to the other end side, and can be made harder to oscillate compared to a state where it is not biased. Further, a discharge port 2b is provided on one end side in the pump chamber P, and the biasing direction described above is the same as the direction in which the pump rotor 8 is biased by the oil on the discharge port 2b side (one end side). The biasing effect toward the end side is large. Therefore, wear of the shaft support hole 1a can be further suppressed, and as a result, the effect of maintaining high pump performance and high silence when the electric pump is operated can be further improved.

  (3) Since the motor rotor 9 is a flat rotor whose diameter is larger than the axial length, the overall axial length of the electric pump can be shortened and the maximum distance from the shaft support hole 1a is reduced. It is possible to reduce the displacement in the radial direction during rotation (the amplitude of the plowing motion), and thus, for example, high quietness can be obtained.

The above embodiment may be modified as follows.
In the above embodiment, the stator case 3 has the large cylinder portion 3a, the disk portion 3b, and the stator case side imprint cylinder portion 3c. The pump housing side imprint cylinder portion 1c is provided on the stator case side imprint cylinder portion 3c. Although it is assumed that the seal is fitted (within a long range in the axial direction), the shape and configuration of the portion may be changed as long as the seal fits with the pump housing.

  For example, as shown in FIG. The stator case 31 is made of a metal plate, and has a large cylindrical portion 31a to which the motor stator 6 is fixed. The cylindrical part 1c has a stator case side stamping disc part 31b to which the stamping is fitted. In this case, since the stator case 31 is made of a metal plate material, the stator case can be manufactured at a low cost while having high rigidity (compared to a resin case or the like). In addition, the stator case 31 can be manufactured at a lower cost as a simple shape compared to the above-described embodiment having the stator case side stamped cylinder portion 3c.

  -Although the axial length (thickness) of each part was constant in the rotor core 15 of the said embodiment, it is not limited to this, The axial direction length of the radial direction inner part into which the rotating shaft 7 is press-fitted May be formed shorter than the axial length of the radially outer portion.

  Specifically, for example, as shown in FIG. In the rotor core 41 of this example, the axial length of the radially inner portion 41a is formed short, so that an anti-pump side annular recess 41b is formed on the opposite side (right side in the drawing) of the pump housing 1.

  In this way, the weight of the rotor core 41 can be reduced. Therefore, for example, the weight moment on the motor rotor 9 side can be reduced and set to easily match the weight moment on the pump rotor 8 side. Further, since the anti-pump side annular recess 41b is formed on the opposite side of the pump housing 1 (the right side in the figure and far from the shaft support hole 1a), the pump side annular recess is formed only on the pump housing 1 side. The weight moment on the motor rotor 9 side can be made smaller than that of the motor. Therefore, for example, the weight moment on the motor rotor 9 side and the weight moment on the pump rotor 8 side can be set so as to easily match.

  Further, for example, it may be changed as shown in FIG. In the rotor core 42 in this example, a pump-side annular recess 42b is formed on the pump housing 1 side by forming the radial inner portion 42a to have a short axial length. At least a part (all in this example) of the oil seal 11 is disposed in the pump-side annular recess 42b.

  In this way, the weight of the rotor core 42 can be reduced. Therefore, for example, the weight moment on the motor rotor 9 side can be reduced and set to easily match the weight moment on the pump rotor 8 side. In addition, since at least a part (all in this example) of the oil seal 11 is disposed in the pump-side annular recess 42b, the oil-seal 11 is not disposed in the pump-side annular recess 42b (for example, the above embodiment (see FIG. 1) and Compared to another example (see FIG. 6A)), the entire axial length of the electric pump can be shortened.

  For example, as shown in FIG.6 (c), you may change. In the rotor core 43 in this example, the axial length of the radially inner portion 43a is formed to be short, so that an anti-pump side annular recess 43b is formed on the opposite side of the pump housing 1 and the pump side on the pump housing 1 side. An annular recess 43c is formed. In the pump-side annular recess 43c, at least a part of the oil seal 11 (substantially half in this example) is disposed. Even if it does in this way, the effect similar to the effect of the said other example can be acquired.

  In the above-described embodiment, the diameter of the seal fitting portion between the pump housing 1 and the stator case 3 (that is, the outer diameter of the pump housing side stamping cylinder portion 1c and the inner diameter of the stator case side stamping cylinder portion 3c) is the motor stator 6 However, the present invention is not limited to this, and may be set to be the same.

  In the above embodiment, the pump housing 1 and the stator case 3 extend through the axial ends on the side away from each other (from the pump end plate 2 that is a member at both ends of the electric pump to the heat sink cover 5). However, the present invention is not limited to this, and may be fixed by another configuration.

  In the above embodiment, the resin case member 4 is sandwiched between the stator case 3 and the heat sink cover 5, but the present invention is not limited to this, and this portion may be changed to another configuration.

In the above embodiment, the circuit housing recess 5a has the large recess 5b and the small recess 5c. However, the present invention is not limited to this. For example, it may be a circuit housing recess having a certain depth.
In the above embodiment, the heat dissipating fin portion 5d protruding in the axial direction is formed on the back surface of the small recess 5c of the heat sink cover 5. However, the present invention is not limited to this. For example, the heat dissipating fin portion 5d is not formed. A heat sink cover may be used, and a heat radiating fin portion may be formed on the back surface of the large recess 5b.

  In the above embodiment, the power transistor 22 is accommodated in the small recess 5c. However, the present invention is not limited to this, and the power transistor 22 may not be accommodated. The power transistor 22 is in contact with the bottom surface of the small recess 5c via the silicone rubber 24. However, the present invention is not limited to this. For example, the configuration does not include the silicone rubber 24 and does not contact the bottom surface of the small recess 5c. It is good.

  In the above embodiment, the circuit case member 4 has the lead-out holding groove 4g, and the stator case 3 and the circuit case member 4 have the holding structure portion (the caulking piece 3e and the caulking portion 4e) that cannot move relative to each other. However, the present invention is not limited to this, and it may be configured not to have the lead-out holding groove 4g and the holding structure part (the caulking piece 3e and the caulking part 4e). In addition, the lead-out holding groove 4g (lead-out holding portion) of the above-described embodiment is only required to hold the coil connection end 6c and lead out to the circuit accommodating recess 5a side. It may be changed.

In the above embodiment, the rotor core 15 is a laminated core formed by laminating core sheets, but is not limited thereto, and may be changed to a rotor core made of sintered metal, for example.
In the above embodiment, the motor rotor 9 is a continuous pole type rotor, but is not limited to this, and may be changed to another type of rotor.

  In the above embodiment, the motor stator 6 is provided such that the axial center thereof is located at a position shifted in the axial direction from the axial center of the motor rotor 9. You may provide so that a center may correspond.

  In the above embodiment, the motor stator 6 is provided so that its axial center is displaced to the other end side, that is, the side away from the pump chamber P, from the axial center of the motor rotor 9. However, the present invention is not limited to this, and it may be provided so as to be displaced to one end side, that is, the pump chamber P side.

  In the above embodiment, the motor rotor 9 is a flat rotor whose diameter is larger than the axial length, but is not limited thereto, and may be changed to a rotor whose axial length is larger than the diameter. .

  In the above embodiment, the pump rotor 8 (pump action part) is of the inscribed gear type. However, if the fluid can be sucked and discharged, the pump rotor 8 (pump action part) can be changed to another pump rotor (pump action part). Good.

  In the above embodiment, the electric pump for circulating the vehicle oil is used. However, the electric pump may be used for other purposes.

  DESCRIPTION OF SYMBOLS 1 ... Pump housing, 1a ... Shaft support hole, 1b ... Pump chamber recessed part (pump chamber structure part), 2a ... Suction port, 2b ... Discharge port, 3,31 ... Stator case, 6 ... Motor stator, 7 ... Rotating shaft, DESCRIPTION OF SYMBOLS 8 ... Pump rotor (pump action part), 9 ... Motor rotor, 11 ... Oil seal, 15, 41, 42, 43 ... Rotor core, 41a, 42a, 43a ... Radially inner part, 41b, 43b ... Anti-pump side annular recessed part, 42b, 43c ... pump side annular recess, P ... pump chamber, S ... storage chamber.

Claims (6)

A rotation axis;
A pump action part provided on one end side of the rotating shaft;
A motor rotor provided on the other end of the rotating shaft;
A pump housing having a shaft support hole that rotatably supports an intermediate portion of the rotation shaft, and a pump chamber constituting portion constituting a part of the pump chamber on one end side of the shaft support hole;
An electric pump that is fixed to the other end of the pump housing, includes a stator case that houses and fixes a motor stator therein, and houses the motor rotor inside the motor stator,
The weight moment on the pump rotor side and the weight moment on the motor rotor side coincide with each other from the axial center of the shaft support hole in the rotary member composed of the rotary shaft, the pump rotor provided as the pump action portion, and the motor rotor. An electric pump characterized by being set. The electric pump according to claim 1,
The one end side in the pump chamber is provided with a suction port and a discharge port,
The electric pump characterized in that the motor stator is provided such that its axial center is displaced to the other end side with respect to the axial center of the motor rotor. The electric pump according to claim 1 or 2,
The electric pump according to claim 1, wherein the motor rotor is a flat rotor having a diameter larger than an axial length. The electric pump according to any one of claims 1 to 3,
The rotor core of the motor rotor is an electric pump characterized in that the axial length of the radially inner portion into which the rotating shaft is press-fitted is shorter than the axial length of the radially outer portion. The electric pump according to claim 4, wherein
The electric pump according to claim 1, wherein an anti-pump side annular recess is formed on the opposite side of the pump housing by forming the radial inner portion of the rotor core in a short axial length. The electric pump according to claim 4 or 5,
In the rotor core, a pump-side annular recess is formed on the pump housing side by forming an axial length of the radially inner portion short.
In the pump-side annular recess, at least one oil seal that divides the pump chamber side and the housing chamber side in which the motor stator is housed in a state of being fitted on the rotating shaft while being held by the pump housing. An electric pump characterized in that a portion is arranged.