JP2013217237A - Electric oil pump device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric oil pump device capable of preventing malfunction of a control board and breakage of electronic components mounted on the control board due to static electricity intruded in a motor housing.SOLUTION: A metal dielectric member 24 extending in an axial direction is coaxially press-fitted in and fixed to a rear end face of a rotary drive shaft 7. The dielectric member 24 contactlessly penetrates a through-hole 26 provided in a control board 4, and an end face of the same extends close to a breathing hole 23 for communication between an inside and an outside of a cover 20, faces the breathing hole 23 and rotates together with the rotary drive shaft 7. The dielectric member 24 is formed to have such a tapered shape in the axial direction that a diameter of a portion contactlessly penetrating the through-hole 26 of the control board 4 is smaller than a diameter of the through-hole 26 and a diameter of a rear end axially facing the breathing hole 23 is smaller than a diameter of a front end on a rotary drive shaft 7 side.

Description

  The present invention relates to an electric oil pump device.

  Conventionally, a specific example of an electric oil pump device includes a combination of an oil pump that circulates fluid (oil) and an electric motor that drives the oil pump. Also, this electric oil pump device has been proposed in which a control board for motor control is housed in a control chamber formed on the opposite side of the oil pump in the housing of the electric motor (for example, Patent Documents). 1). This control board is accommodated in a control chamber provided in the motor housing and covered with a lid, so that waterproofness is ensured.

JP 2009-156081 A

  In the electric oil pump device as described above, the resin member of the motor housing that houses the control board on which the electronic components that drive the electric motor are mounted and the lid that covers the opening of the motor housing are bonded together by welding. . In order to cope with a sudden temperature change due to heat generated by the electric motor in the usage environment, the lid is provided with a breathing hole that penetrates the inside and outside of the motor housing, air is circulated through the breathing hole to dissipate heat, and It is necessary to keep the outside at the same pressure or temperature. However, static electricity may enter the motor housing from the outside through this breathing hole. For this reason, if the distance from the breathing hole to the electronic component mounted on the control board is short, the intruding static electricity reaches the electronic component on the control board, the control board malfunctions, or the electronic part on the control board There is a possibility of damage.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an electric oil pump that can prevent malfunction of a control board and damage of electronic components mounted on the control board due to static electricity that has entered the motor housing. To provide an apparatus.

  In order to solve the above-mentioned problem, the invention according to claim 1 is a metal oil pump in which a pump rotor is rotatably supported around a rotation axis in a pump chamber formed between a pump plate and a pump housing. And an electric motor that is provided adjacent to the oil pump in the direction of the rotational axis and rotationally drives the pump rotor, and is rotatably supported by the pump housing and connects the pump rotor and the rotor of the electric motor. A metal rotating shaft, a control chamber formed on the opposite side of the oil pump in the housing of the electric motor, and a control board for driving and controlling the electric motor, and an opening of the control chamber, A lid having a breathing hole communicating with the outside of the control chamber is formed on the rotation axis, and extends so as to extend to the vicinity of the breathing hole of the lid on the rotation shaft. A dielectric member provided with conductive integrally on a line, and the gist that a through-hole in which the formed dielectric member to the control board in order to penetrate in a non-contact manner.

  The invention according to claim 2 is summarized in that, in the electric oil pump device according to claim 1, the rotating shaft is supported by the pump housing by a conductive bearing.

  According to a third aspect of the present invention, in the electric oil pump device according to the first or second aspect, the diameter of one end side of the dielectric member facing the breathing hole is integrally connected to the rotating shaft. The gist is that it is smaller than the diameter of the other end side.

  According to the first aspect of the present invention, the conductive dielectric member is integrally connected to the rotation axis on the coaxial line, the through hole provided in the control board is passed through in a non-contact manner, and the inside of the lid is communicated with the outside. Since it is arranged so as to extend to the vicinity of the breathing hole, even if static electricity enters from the breathing hole, the static electricity is discharged from the oil pump to the external chassis through the metal rotating shaft through the dielectric member. For this reason, static electricity can be prevented from reaching the electronic component mounted on the control board, and the electronic component can be electrically protected. As a result, it is possible to improve the antistatic performance for the electronic component mounted on the control board.

  According to the invention of claim 2, since the rotating shaft is supported by the pump housing by the conductive bearing, static electricity flows from the conductive bearing directly to the pump housing through the rotating shaft and is discharged along a path away from the oil pump. To do. For this reason, the discharge in oil can be suppressed and the electric corrosion of a pump plate can be prevented.

  According to the invention of claim 3, since the dielectric member has a smaller diameter on the side facing the breathing hole than that on the side integrally connected to the rotating shaft, the weight of the dielectric member can be reduced. It is possible to maintain the rigidity of the rotation shaft, prevent the deflection of the dielectric member during rotation, and prevent the dielectric member from contacting the control board.

1 is a longitudinal sectional view of an electric oil pump device according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of a control board portion in FIG. 1. Schematic which shows the discharge route of the static electricity which concerns on this embodiment.

Next, an electric oil pump device according to an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a longitudinal sectional view of an electric oil pump device 1 according to an embodiment of the present invention. As shown in FIG. 1, an electric oil pump device 1 is used as a hydraulic pump for an automobile transmission, and an oil pump (for example, an internal gear pump) 2 and an electric motor 3 that rotationally drives the oil pump 2 are disposed in a housing. It is integrated. A control board (controller) 4 is also incorporated in the housing. An electric motor (hereinafter referred to as a brushless motor) 3 shown in FIG. 1 is a brushless sensorless motor having a three-phase winding. The electric oil pump device 1 is fastened and fixed to a transmission or an engine case (not shown) via a plurality of flanges protruding from the end face of the pump plate 14 with bolts arranged in the circumferential direction with respect to the axis center through an attachment hole. Has been. In the following description, the left side of the drawing is the front and the right side is the rear.

  The oil pump 2 uses a trochoid curved pump here, and an inner rotor for pump (hereinafter referred to as an outer rotor) 11 having outer teeth on a pump outer rotor (hereinafter referred to as outer rotor) 11 having inner teeth having a trochoidal tooth profile. (Hereinafter referred to as the inner rotor) 12 is engaged, and the pump rotor including the outer rotor 11 and the inner rotor 12 is eccentrically disposed in the pump housing 15 so as to be rotatable.

  The inner rotor 12 is externally fitted and fixed to a portion of the rotary drive shaft (rotary shaft) 7 that is closer to the front than the portion where the rotor 6 is formed, and rotates together with the rotary drive shaft 7. The outer rotor 11 has one more internal tooth than the outer teeth of the inner rotor 12, and is arranged so as to be rotatable in the pump housing 15 around a position eccentric with respect to the rotational drive shaft 7. Further, the inner rotor 12 rotates with its outer teeth meshing with the inner teeth of the outer rotor 11 at a part of its entire circumference, and each outer tooth substantially inscribed in the inner surface of the outer rotor 11 at various locations around the entire circumference. ing.

  Therefore, when the rotational drive shaft 7 is rotationally driven by the brushless motor 3, the volume of the gap between the outer rotor 11 and the inner rotor 12 of the oil pump 2 repeatedly expands and contracts during one rotation of the rotational drive shaft 7. A pump operation is performed to feed oil from an import (not shown) provided in the pump plate 14 leading to these gaps toward the outport.

  The pump plate 14 and the pump housing 15 constituting the housing of the oil pump 2 are made of a metal nonmagnetic material (for example, aluminum die casting). The motor housing 17 and the cover (lid) 20 that house the brushless motor 3 are formed of a thermoplastic resin material (for example, nylon resin). The housing body of the electric oil pump device 1 includes the pump plate 14, the pump housing 15, the motor housing 17, and the cover 20. Here, the motor housing 17 and the cover 20 form a waterproof housing.

  The motor housing 17 has a cylindrical shape, and its front end is fixed to a portion near the outer periphery of the rear surface of the pump housing 15 via an oil seal 27. The rear end opening of the motor housing 17 is closed by the cover 20.

  The pump housing 15 is a thick plate having a radial extension, and a pump chamber 13 having an open front is formed at the center thereof. A pump plate 14 is fixed to the front surface of the pump housing 15 via an O-ring 16, and the front surface of the pump chamber 13 is closed. An outer rotor 11 constituting the oil pump 2 is rotatably accommodated in the pump chamber 13, and an inner rotor 12 that meshes with the inner rotor 12 is disposed inside the outer rotor 11. The pump plate 14 is provided with a suction port and a discharge port penetrating in the axial direction.

  Next, the brushless motor 3 includes a rotating motor rotor (hereinafter referred to as “rotor”) 6 and a motor stator (hereinafter referred to as “stator”) 5 fixed to the outside of the outer peripheral surface of the rotor 6. The rotor 6 is formed by arranging, for example, a plurality of permanent magnets 8 along the circumferential direction on the outer peripheral surface of the rotary drive shaft 7. The rotation drive shaft 7 is a rotation shaft shared by the brushless motor 3 and the oil pump 2.

  A cylindrical portion having a smaller diameter than the motor housing 17 is integrally formed at the center of the rear end surface of the pump housing 15, and the rotary drive shaft 7 extending in the front-rear direction is cantilevered by bearings 28 and 29 provided at the rear portion in the cylindrical portion. Has been. In this example, the bearings 28 and 29 are ball bearings which are two rolling bearings adjacent to each other in the front and rear, the inner rings of the bearings 28 and 29 are fixed to the rotary drive shaft 7, and the outer rings are fixed to the cylindrical portion. Yes. The front portion of the rotary drive shaft 7 passes through a hole formed in the rear wall of the pump housing 15 and enters the pump chamber 13, and the front end thereof is connected to the inner rotor 12. An oil seal 27 is provided between a portion on the inner side of the cylindrical portion in front of the bearings 28 and 29 and the rotary drive shaft 7.

  A rotor 6 constituting the brushless motor 3 is fixed to a rear end portion of the rotary drive shaft 7 protruding rearward from the cylindrical portion. The rotor 6 is formed in a cylindrical shape extending radially from the rear end of the rotary drive shaft 7 and surrounding the outer periphery of the bearings 28 and 29, and the permanent magnet 8 is provided on the outer periphery thereof. More specifically, the rotor 6 includes a perforated disc portion of the rotor core 10 and a cylindrical portion integrally formed on the outer periphery thereof, and the inner periphery of the disc portion is fixed to the rotary drive shaft 7, and the cylindrical portion Permanent magnets 8 are provided on the outer periphery. The axial position of the center of gravity of the rotating portion including the rotary drive shaft 7, the rotor 6 and the inner rotor 12 of the oil pump 2 is within the axial range of the bearings 28 and 29. In this embodiment, the axial position of the center of gravity is between the two ball bearings constituting the bearings 28 and 29.

  In the stator 5, a plurality of inward salient poles (teeth) of the stator core 9 are arranged outside the outer peripheral surface of the rotor 6 through a slight air gap. A coil 19 is wound around each tooth of the stator core 9. Here, in order to insulate the coil 19 from the stator core 9, insulators 18 are mounted from both axial ends of the stator core 9.

  Further, in the electric oil pump device 1 of the present embodiment, the control board 4 is accommodated in the control chamber 21 formed at the rear end of the motor housing 17 and attached to the motor housing 17 as a controller for controlling the brushless motor 3. Yes. The control board 4 is based on an inverter circuit that converts a DC power source into AC and supplies a drive current to each coil 19 of the brushless motor 3 and information on the rotational position of the outer rotor 11 detected by a sensor such as a Hall element. A control circuit for controlling the inverter circuit is mounted. On both surfaces of the control board 4, electronic components 22 such as a microcomputer, an IC, a capacitor, and a coil of the above circuit constituting the control board 4 are mounted.

  With the above configuration, the drive current controlled by the control board 4 is supplied to each coil 19 of the brushless motor 3. As a result, a rotating magnetic field is generated in the coil 19, torque is generated in the permanent magnet 8, and the rotor 6 is rotationally driven. Thus, when the inner rotor 12 is driven to rotate, the outer rotor 11 is driven and rotated, and the gap between the inner teeth of the outer rotor 11 and the outer teeth of the inner rotor 12 is repeatedly expanded and contracted. Pump operation is performed to suck and discharge oil through the port.

  The motor housing 17 and the cover 20 are brought into contact with the fixed motor housing 17 while rotating the cover 20, and are welded to each other by frictional heat generated by rotation, for example, by spin welding. Here, in order to adjust the pressure difference between the inside and outside of the motor housing 17 due to a rapid temperature change of the brushless motor 3 in the usage environment, the cover 20 has an oil pump that communicates the space inside and outside the motor housing 17. A breathing hole 23 extending from one surface to the opposite surface in the axial direction of 2 is provided. Further, a seal 25 covering the breathing hole 23 is fixed to the inner surface of the cover 20, and this seal 25 blocks water and allows air to pass through.

  A metal dielectric member 24 extending in the axial direction is press-fitted coaxially and connected to the rear end surface of the rotary drive shaft 7. The dielectric member 24 penetrates the through hole 26 provided in the control board 4 in a non-contact manner, extends to the vicinity of the breathing hole 23 that communicates the inside and the outside of the cover 20, and rotates together with the rotary drive shaft 7. .

  Next, FIG. 2 is a schematic cross-sectional view of the control board 4 portion in FIG. In the following description, the lower side of the drawing is the front and the upper side is the rear. As shown in FIG. 2, the motor housing 17 has a cylindrical shape, and a recess is formed on the entire surface of the welding surface with the cover 20. An annular welding rib is formed on the front side of the cover 20 that covers the opening of the motor housing 17. The motor housing 17 and the cover 20 are both made of a resin material, and are welded by heating and melting the welding rib while rotating the lid 18 and pressing it against the recessed portion of the fixed motor housing 17 of the mating part. Here, spin welding is used as this bonding method.

  The cover 20 is provided with a breathing hole 23 that communicates between the outside and the inside of the motor housing 17 in order to adjust a pressure difference between the inside and outside of the motor housing 17 due to a rapid temperature change of the brushless motor 3 in a use environment after welding. ing. For example, in this embodiment, the breathing hole 23 is a stepped through hole. Further, since the control board 4 on which the electronic component 22 is mounted is accommodated in the control chamber 21 in the motor housing 17 in an airtight manner, the cover 20 has a waterproof / dustproof structure that closes the breathing hole 23 on the front surface (inner surface) side. A resin seal (for example, a waterproof and moisture-permeable material) 25 is attached and fixed. Since the seal 25 allows gas (air) to pass therethrough, even if the air flows through the intake hole 23 and the seal 25 and the temperature of the brushless motor 3 changes rapidly, the inside and outside of the motor housing 17 are maintained at the same pressure. .

  A metal dielectric member 24 extending in the axial direction is press-fitted and fixed coaxially to the rear end surface of the rotary drive shaft 7. The dielectric member 24 penetrates the through hole 26 provided in the control board 4 in a non-contact manner, and its end surface extends to the vicinity of the breathing hole 23 and faces the front surface of the cover 20 and rotates along with the rotary drive shaft 7. To do. Here, the dielectric member 24 is configured such that the diameter of the portion of the control board 4 that penetrates the through hole 26 is not in contact with the inner surface of the through hole 26 and is smaller than the diameter of the through hole 26, and the rear end facing the breathing hole 23 in the axial direction. The diameter of the part is smaller than the diameter of the front end part integrally connected to the rotary drive shaft 7. For example, in the present embodiment, the dielectric member 24 has a tapered shape in which the tip on the cover 20 side becomes narrower in the axial direction.

  FIG. 3 is a schematic view showing a discharge path of static electricity according to the present embodiment. As shown in FIG. 3, the static electricity that has entered through the breathing hole 23 flows from the pump plate 14 to the externally grounded (grounded) metal portion through the metal dielectric member 24 and the rotary drive shaft 7 (FIG. 3, arrow). (See dashed line a). Further, when conductive bearings are used for the bearings 28 and 29, static electricity that has entered through the breathing hole 23 flows from the pump housing 15 to the outside through the conductive bearings 28 and 29, through a position further away from the oil pipe. (See FIG. 3, arrow broken line b).

  Next, the operation and effect of the electric oil pump device 1 according to the present embodiment configured as described above will be described.

  According to the above configuration, in the electric oil pump device 1 in which the oil pump 2, the electric motor 3, and the control board 4 are arranged side by side in the rotation axis direction of the oil pump 2, the electronic component 22 that is a circuit component of the controller is mounted. The control board 4 is accommodated in the control chamber 21 at the rear end of the motor housing 17, and the cover 20 covers the opening of the motor housing 17. The motor housing 17 and the cover 20 are made of a resin material, and are joined by, for example, spin welding. At this time, a breathing hole 23 is provided in the central portion of the cover 20 in order to adjust a pressure difference between the inside and outside of the motor housing 17 caused by a rapid temperature change of the brushless motor 3 in the use environment.

  A metal dielectric member 24 extending in the axial direction is press-fitted and fixed to the rear end face of the rotary drive shaft (rotary shaft) 7. The dielectric member 24 penetrates the through hole 26 provided in the control board 4 in a non-contact manner, faces the breathing hole 23 that communicates the inside and the outside of the cover 20, extends to the vicinity of the breathing hole 23, and is rotationally driven. Along with the shaft 7. In the dielectric member 24, the diameter of the portion of the control board 4 that penetrates the through hole 26 in a non-contact manner is smaller than the diameter of the through hole 26, and the diameter of the rear end surface facing the breathing hole 23 in the axial direction is It is formed smaller than the diameter of the front end. The rotary drive shaft 7 can be supported by the pump housing 15 by bearings 28 and 29 which are conductive bearings.

  Thereby, even if static electricity enters from the breathing hole 23, the static electricity is discharged from the pump plate 14 to the external chassis through the rotary drive shaft 7 through the dielectric member 24. For this reason, static electricity is suppressed from reaching the electronic component 22 on the control board 4, and the electronic component 22 can be electrically protected. As a result, the antistatic performance with respect to the electronic component 22 mounted on the control board 4 can be improved. Further, static electricity flows from the conductive bearings 28 and 29 to the pump housing 15 through the rotary drive shaft 7 and is discharged along a path away from the oil pump 2. For this reason, the discharge in oil can be suppressed and the electrolytic corrosion of the pump plate 14 of the oil pump 2 can be prevented. Further, the weight of the dielectric member 24 can be reduced, the core of the dielectric member 24 can be prevented during rotation while maintaining the rigidity of the rotary drive shaft 7, and the dielectric member 24 can be prevented from contacting the control board 4. . Further, as countermeasures against static electricity, it is not necessary to change the size of the motor housing 17 and the cover 20 or to newly provide another part (for example, an insulating sheet), and the cost can be suppressed.

  As described above, according to the present embodiment, it is possible to provide an electric oil pump device that can prevent malfunction of a control board and damage to electronic components mounted on the control board due to static electricity that has entered the motor housing.

  Although one embodiment according to the present invention has been described above, the present invention can also be implemented in other forms.

  In the above embodiment, the example in which the dielectric member 24 has a tapered shape is shown, but the present invention is not limited to this, and a step on the small diameter side is formed in the axial direction from the large diameter side of the rear end portion of the rotary drive shaft 7. It may be done.

  In the above embodiment, the case of spin welding as an adhesion method between resin materials is shown, but the present invention is not limited to this, and hot plate welding, ultrasonic welding, vibration welding, infrared welding, etc., or an adhesive Adhesion by may also be used.

  Moreover, although the case where the internal gear type pump was used as the oil pump 2 was shown in the said embodiment, it is not limited to this, The rotary pump using a vane drive, an external gear, etc. may be sufficient. Further, as an inscribed gear pump, an inner tooth is provided on the inner peripheral side of the outer rotor 11, and it is eccentrically rotated while meshing with the inner rotor 12 having the outer teeth. As long as the volume of the partitioned gap is an internal gear pump that repeats expansion and contraction, it is not necessarily limited to the trochoid curve type pump as described above. Further, the inner teeth of the outer rotor 11 and the outer teeth of the inner rotor 12 are not necessarily formed in a clear so-called tooth shape, and may be protrusions, protrusions, or engaging portions.

  Further, in the above-described embodiment, the case where a plurality of permanent magnets 8 are arranged and fixed on the outer peripheral portion of the rotary drive shaft 7 as the rotor 6 of the brushless motor 3 is shown, but the present invention is not limited to this. You may make it use what fixed the shape permanent magnet.

1: electric oil pump device, 2: oil pump, 3: brushless motor (electric motor), 4: control board, 5: stator for motor, 6: rotor for motor, 7: rotary drive shaft (rotary shaft), 8: Permanent magnet, 9: stator core, 10: rotor core, 11: outer rotor for pump, 12: inner rotor for pump, 13: pump chamber, 14: pump plate, 15: pump housing, 16: O-ring, 17: motor housing, 18: Insulator, 19: Motor coil, 20: Cover (lid), 21: Control room, 22: Electronic component, 23: Breathing hole, 24: Dielectric member, 25: Seal, 26: Through hole, 27: Oil seal, 28, 29: Bearing

Claims (3)

A metal oil pump in which a pump rotor is rotatably supported around a rotation axis in a pump chamber formed between a pump plate and a pump housing;
An electric motor provided adjacent to the oil pump in the direction of the rotation axis and driving the pump rotor;
A metal rotating shaft that is rotatably supported by the pump housing and connects the pump rotor and the rotor of the electric motor;
A control board that is housed in a control chamber formed on the opposite side of the oil pump in the housing of the electric motor, and drives and controls the electric motor;
A lid that covers the opening of the control chamber and that has a breathing hole that communicates with the outside of the control chamber on the rotation axis;
A conductive dielectric member integrally provided on a coaxial line so as to extend to the rotating shaft to the vicinity of the breathing hole of the lid;
An electric oil pump device comprising: a through hole formed in the control board for allowing the dielectric member to pass through in a non-contact manner. The electric oil pump device according to claim 1,
The electric oil pump device, wherein the rotating shaft is supported by the pump housing by a conductive bearing. In the electric oil pump device according to claim 1 or 2,
The electric oil pump device according to claim 1, wherein the dielectric member has a diameter at one end facing the breathing hole smaller than a diameter at the other end connected integrally with the rotation shaft.

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