JPWO2015011740A1 - Electric pump - Google Patents

Abstract

An electric oil pump (1) configured by integrally combining a brushless type electric motor (2) and an oil pump (3) driven to rotate by the electric motor, wherein the electric motor is a motor casing (10). A drive shaft (42) disposed in the motor housing chamber (12) in the motor case and rotatably supported by the motor case, a rotor (40) on the drive shaft, and the rotor outside the circumferential direction. The stator (20) attached to the motor case so as to face and oppose from the side extends between the rotor and the stator so as to face each other, and the motor housing chamber is formed into a space in which the rotor housing chamber (31) and the stator are disposed. A partition case (30) for partitioning, and the drive shaft passes through the motor case and is integrally connected to the pump drive shaft of the oil pump. Is configured to rotate the shift is transmitted to the pump drive shaft comprises a communicating hole for the rotor containing chamber communicates with the suction side of the oil pump (89).

Description

  The present invention relates to an electric pump configured by integrally combining a liquid pump and an electric motor of a type in which a rotor and a stator are rotationally driven without contact.

  In such an electric pump, since the drive shaft of the electric motor is driven integrally with the drive shaft of the liquid pump, the liquid sucked and discharged by the liquid pump has a gap between the drive shaft and the case. There is a risk of passing through and entering the electric motor. For this reason, an electric pump having a configuration in which a liquid-tight seal is provided on the drive shaft so that liquid does not enter the electric motor from the liquid pump is known. In addition, a partition member (can) is provided in the electric motor to partition the region where the stator is disposed and the region where the rotor is disposed. There is also known an electric pump (also referred to as a canned pump) that is prevented from being immersed in the water. For example, Patent Document 1 discloses a canned pump configured by housing a rotor 5 inside a can (partition member) 2 and arranging a stator core portion 8 and a stator coil 9 (stator) outside the can 2. Has been.

  The liquid pump is configured to suck fluid from the outside to the suction side and discharge the fluid from the discharge side to the supply target. Generally, the discharge side has a higher pressure than the suction side. For example, in the case of the can pump as described above, when the fluid leaks from the fluid pump side into the partition member (can 2) and is filled, the internal pressure of the partition member (can 2) becomes high. It gets higher under pressure. For this reason, the partition member (can 2) is required to have sufficient strength to withstand this pressure.

JP 2001-280284 A

  In order to secure the strength that can withstand such a high pressure, it is considered that the thickness of the partition member should be increased to increase the strength, but if the thickness is increased, the stator and the rotor are increased by the thickness. Located away. Here, in the case of a non-contact type electric motor, the rotor is rotationally driven by an electromagnetic force acting on the rotor from the stator. Therefore, when the stator and the rotor are separated from each other, the electromagnetic force acting on the rotor is reduced, and the electric motor There is a problem that driving efficiency is lowered. As can be seen from the fact that the electromagnetic force acting on the rotor from the stator is inversely proportional to the square of the distance between the stator and the rotor, if the thickness of the partition member is increased and the stator and the rotor are separated from each other, As a result, the drive efficiency of the electric motor is significantly reduced. For this reason, in order to ensure the effect of preventing the fluid from entering the stator side by the partition member, it is difficult to improve the driving efficiency of the electric motor if the strength is to be ensured. On the other hand, if it is attempted to improve the driving efficiency of the electric motor, it is difficult to ensure the strength of the partition member, and it is difficult to prevent the fluid from entering the stator side. As described above, there is a problem that it is difficult to reconcile the two problems of ensuring the strength of the partition member and improving the motor driving efficiency.

  The present invention has been made in view of the above problems, and while maintaining the fluid intrusion prevention function by the partition member, the thickness of the partition member is reduced so that the pressure resistance can be lowered. An object of the present invention is to provide an electric pump that can improve the driving efficiency of an electric motor.

  An electric pump according to the present invention is an electric pump (for example, an implementation) configured by integrally combining a brushless type electric motor and a liquid pump (for example, the oil pump 3 in the embodiment) that is rotationally driven by the electric motor. Electric oil pump 1) in the embodiment, wherein the electric motor includes a motor case (for example, motor casing 10 in the embodiment) and a case internal space formed in the motor case (for example, motor housing in the embodiment). A motor drive shaft (for example, drive shaft 42 in the embodiment) disposed in the chamber 12) and rotatably supported by the motor case, a rotor provided on the motor drive shaft, and the rotor in a circular shape. The motor case is located in the space inside the case so as to be opposed from the outside in the circumferential direction. A stator attached to the rotor, and a space extending between the rotor and the stator, and a rotor side space in which the motor drive shaft and the rotor are disposed, and a stator in which the stator is disposed. A partition member (for example, a partition case 30 in the embodiment) that partitions into a side space, the motor drive shaft passes through the motor case and is integrally connected to the pump drive shaft of the liquid pump, and the motor drive shaft The rotation portion is transmitted to the pump drive shaft, and a communication portion (for example, the communication hole 89 in the embodiment) is provided that communicates the rotor side space with the suction side of the liquid pump. It is characterized by.

  In the above-described electric pump, it is preferable that the rotor has a permanent magnet on an outer peripheral portion, and controls the energization of the stator to rotate the motor drive shaft via the rotor. .

  In addition, the rotor is configured to have an induction coil (for example, the rotor coil 143 in the embodiment) on the outer periphery, and the induction force generated in the induction coil is utilized by controlling energization of the stator. It is also preferable to perform control to rotationally drive the motor drive shaft.

  According to the present invention, by providing the communication portion, the liquid inside the partition member can be discharged to the suction side of the liquid pump, and the internal pressure of the partition member can be kept as low as the suction side of the liquid pump. For this reason, since the pressure resistance strength can be lowered while maintaining the fluid intrusion prevention function by the partition member, the partition member is thinned to reduce the facing distance between the stator and the rotor, and the drive efficiency of the electric motor An electric pump with improved efficiency can be realized.

It is sectional drawing which shows the electric oil pump to which this invention is applied. It is sectional drawing which shows the electric motor used for the said electric oil pump along II-II in FIG. It is sectional drawing which shows the oil pump used for the said electric oil pump along III-III in FIG. It is sectional drawing which shows the electric motor which concerns on a modification.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a cross-sectional view of an electric oil pump 1 as an example to which the present invention is applied. First, the overall configuration of the electric oil pump 1 will be described with reference to FIG. In the embodiment described below, for convenience of explanation, the front and rear, the left and right (the arrow is not shown in FIG. 1, but the direction perpendicular to the page), and the top and bottom are defined by arrows attached to each drawing. I do. Moreover, in this embodiment, the electric oil pump 1 which draws in the lubricating oil stored in the tank (for example, engine oil pan) provided in the vehicle and discharges it to the lubricating oil path connected to each part of the engine is illustrated.

  The electric oil pump 1 includes an electric motor 2 that outputs a rotational driving force, and an oil pump 3 that is driven by the electric motor 2 and discharges sucked lubricating oil to a lubricating oil passage.

  The electric motor 2 includes a motor casing 10 having a substantially cylindrical motor housing chamber 12 having a central axis extending in the front-rear direction, a stator 20 disposed along the inner peripheral surface in the motor housing chamber 12 of the motor casing 10, and A partition case 30 having a substantially bottomed cylindrical rotor accommodating chamber 31 and disposed on the inner periphery of the stator 20, and a rotor 40 rotatably disposed in the rotor accommodating chamber 31 of the partition case 30 are provided. Configured.

  The motor casing 10 includes a main motor case 11 in which a bottomed cylindrical space that opens rearward is formed, and a sub motor case 80 that is assembled at the rear of the main motor case 11 so as to cover the bottomed cylindrical space. Consists of Thus, the motor housing chamber 12 is formed by the bottomed cylindrical space of the main motor case 11 covered with the sub motor case 80. The sub motor case 80 constitutes a pump casing 70 having a gear arrangement chamber 81 with a pump cover 90 to be described later assembled in the rear part. As can be seen from this, the sub motor case 80 is used for both the motor casing 10 and the pump casing 70. The “motor case” defined in the claims is composed of the main motor case 11 and the sub motor case 80.

  The main motor case 11 is formed using a non-magnetic material so that the influence on the magnetic force generated by the stator 20 and the rotor 40 can be suppressed.

  FIG. 2 shows a cross section taken along the line II-II in FIG. 1. As can be seen from FIG. 2, the stator 20 is attached to the inner peripheral surface of the main motor case 11 and is substantially elliptical in cross section. And a plurality of stator cores 21 extending radially inward, and a stator coil 22 provided so as to surround the stator core 21. Six stator cores 21 are formed on the inner peripheral surface of the main motor case 11 so as to be arranged at equal intervals along the circumferential direction, and a stator coil 22 is provided on each stator core 21. The stator core 21 may be configured to be substantially rectangular in cross section or substantially circular in cross section and extend radially inward, or may be configured integrally with the main motor case 11.

  The partition case 30 has a bottomed cylindrical shape with an open rear portion, and has a cylindrical front shaft support portion 32 at the front center (bottom center). The partition case 30 is formed using a non-magnetic material, and has a configuration that suppresses the influence on the magnetic force generated by the stator 20 and the rotor 40, that is, a configuration that does not interfere with electromagnetic force transmission from the stator 20 to the rotor 40. . A front shaft support portion 32 formed at the bottom center of the partition case 30 rotatably supports a drive shaft 42 described later. The partition case 30 is attached to the sub motor case 80 by fitting and joining a rear end portion thereof to a ring-shaped convex portion formed on the front surface of the sub motor case 80, and is a rotor composed of a space on the inner peripheral side of the partition case 30. The storage chamber 31 is partitioned from the outer space in a liquid-tight state. In other words, the motor housing chamber 12 is partitioned by the partition case 30, and an outer peripheral side space (referred to as a stator side space) and an inner peripheral side space (which is a rotor accommodating chamber 31, which is also referred to as a rotor side space). A compartment is formed in a liquid-tight state.

  The rotor 40 includes a rotor core 41 that is formed in a cylindrical shape and whose central axis extends in the front-rear direction, and a plurality of permanent magnets 43 that are formed in a substantially rectangular flat plate shape and are attached to the outer periphery of the rotor core 41. Composed. A drive shaft 42 is inserted into and attached to the rotor 40 at the center of the rotor core 41 in the front-rear direction. As shown in FIG. 2, four permanent magnets 43 are attached so as to be arranged at equal intervals along the circumferential direction of the rotor core 41. These permanent magnets 43 are arranged such that the magnetic poles (S pole or N pole) on the radially outer surface are different between adjacent permanent magnets 43. The rotor 40 is rotatably supported at the front portion of the drive shaft 42 by the front shaft support portion 32 and at the rear portion by a rear shaft support portion 83 of a sub motor case 80 described later, with the rotation axis C as the center of rotation. The rotor core 41, the drive shaft 42, and the permanent magnet 43 rotate integrally.

  The electric motor 2 also includes a rotational position detector 44 disposed between the bottom of the main motor case 11 and the bottom of the partition case 30 and a controller 45 that controls energization of the stator coil 22. The rotational position detector 44 is configured using, for example, a Hall element, detects the magnetic pole and magnetic field strength of the rotor 40 (permanent magnet 43), and outputs a detection signal corresponding to the detection result to the controller 45. The controller 45 calculates the rotational position of the rotor 40 on the basis of the detection signal input from the rotational position detector 44, performs energization control to the stator coil 22 according to the calculation result, and generates electromagnetic waves generated in the stator 20. The rotational drive control of the rotor 40 is performed by controlling the force. This rotation drive control is performed based on, for example, a rotation request input in response to an external switch operation. The electric motor 2 is also referred to as a synchronous motor or an inner rotor type brushless motor.

  As shown in FIGS. 1 and 3, the oil pump 3 houses a drive gear 50 and a driven gear 60 that are rotatably provided around rotation axes parallel to each other and are externally meshed, and the drive gear 50 and the driven gear 60. This is an externally meshing gear pump constituted by a pump casing 70 to be held.

  The pump casing 70 includes the above-described sub motor case 80 and a pump cover 90 attached to the rear surface of the pump casing 70. The sub motor case 80 is formed with a gear arrangement chamber 81 that is accommodated and held in a state where the gears 50 and 60 are in sliding contact with the tooth tips and the front and rear side surfaces. The pump cover 90 is attached to the sub motor case 80 (electric motor 2) by being screwed with a set bolt 4 so as to close the gear arrangement chamber 81. As a result, the gear disposition chamber 81 is defined in the pump casing 70 by being sandwiched between the sub motor case 80 and the pump cover 90.

  The drive gear 50 is connected and supported on the rear end portion of the drive shaft 42 constituting the rotor 40 described above, and rotates integrally with the drive shaft 42 as the rotor 40 rotates. The driven gear 60 is connected and supported on a driven shaft 82 that extends in parallel with the drive shaft 42, and is rotated integrally with the driven shaft 82 according to the rotation of the drive gear 50. Both ends of the driven shaft 82 are rotatably supported by the sub motor case 80 and the pump cover 90, respectively. Alternatively, the driven shaft 82 may be fixedly supported, and the driven gear 60 may be rotatably supported thereon. Both gears 50 and 60 are involute tooth spur gears and are formed in the same cross-sectional shape.

  As shown in FIG. 3, the gear disposition chamber 81 formed inside the pump casing 70 is partitioned by both gears 50 and 60, and the left side of both gears 50 and 60 is the suction chamber 84 and the right side is the discharge chamber 85. Yes. The pump cover 90 is formed with a suction port 91 that communicates with the suction chamber 84 and a discharge port 92 that communicates with the discharge chamber 85 while being attached to the sub motor case 80. The suction chamber 84 is communicated with the tank via the suction port 91, and the discharge chamber 85 is communicated with the lubricating oil path via the discharge port 92.

  In a state where the oil pump 3 is assembled with the rear surface of the sub motor case 80 covered with the front surface of the pump cover 90, the rear surfaces of both gears 50, 60 are in sliding contact with the front surface of the pump cover 90. The front side surface is in sliding contact with a sliding contact wall surface 86 formed on the rear surface of the sub motor case 80 in the gear disposition chamber 81. Thereby, both the gears 50 and 60 are accommodated and held in a state in which movement in the axial direction (front-rear direction) is restricted in the gear arrangement chamber 81.

  In addition, the sub motor case 80 slidably contacts the drive-side partition portion 87 having a drive-side partition surface 87 a having a circular arc shape in plan view that makes the tooth tip 51 of the drive gear 50 slide and contact, and the tooth tip 61 of the driven gear 60. A driven-side partition portion 88 having a driven-side partition surface 88a having a circular arc shape in plan view is formed. The drive side partition portion 87 and the driven side partition portion 88 are formed on the rear surface of the sub motor case 80 in the gear disposition chamber 81, and when the rear surface of the sub motor case 80 is covered with the front surface of the pump cover 90, the pump cover The front surface of 90 is brought into contact with the liquid-tight state. Accordingly, the left suction chamber 84 and the right discharge chamber 85 are partitioned in a liquid-tight state by the drive side partition portion 87, the drive gear 50, the driven gear 60, and the driven side partition portion 88 provided side by side. A compartment is formed. Further, the teeth on the drive gear 50 side filled with lubricating oil to be pumped by the space between the teeth of the drive gear 50, the sliding contact wall surface 86 and the drive side partitioning surface 87 a of the sub motor case 80, and the front surface of the pump cover 90. A leading space 52 is formed. Similarly, a tooth space 62 on the driven gear 60 side is formed by the space between the teeth of the driven gear 60, the sliding wall surface 86 and the driven side partition surface 88 a of the sub motor case 80, and the front surface of the pump cover 90. Further, the sub motor case 80 is formed with a communication hole 89 (see FIGS. 1 and 3) for communicating the suction chamber 84 with the rotor housing chamber 31. In addition, the cross section of the II part in FIG. 3 is shown in FIG.

  In the oil pump 3 configured as described above, when both the gears 50 and 60 are rotated, the lubricating oil is sucked into the suction chamber 84 from the tank through the suction port 91 by the negative pressure acting on the suction chamber 84. The lubricating oil sucked into the suction chamber 84 in this way enters the tooth gaps of both the gears 50 and 60 and is confined in the tooth tip spaces 52 and 62. In this state, the discharge chamber is caused by the rotational movement of the both gears 50 and 60. After being transferred to 85, the oil is discharged from the discharge chamber 85 to the lubricating oil passage through the discharge port 92.

  So far, the overall configuration of the electric oil pump 1 has been described. Next, the operation of the electric oil pump 1 will be described below.

  As described above, drive control of the electric oil pump 1 (electric motor 2) is performed by energization control of the stator coil 22 by the controller 45. When the stator coil 22 is energized by the controller 45, an electromagnetic force is generated in the stator 20 (stator coil 22), and a repulsion generated between the electromagnetic force generated in the stator 20 and the magnetic force in the rotor 40 (permanent magnet 43). The rotor 40 is rotationally driven in the direction corresponding to the energization control with the rotation axis C as the center of rotation using the force and the adsorption force. FIG. 3 illustrates a case where the rotor 40 is driven to rotate clockwise (in the direction of the arrow N1). In this case, the drive gear 50 attached to the drive shaft 42 rotates in the direction of the arrow N1. The driven gear 60 that is externally meshed with the drive gear 50 is driven to rotate in the direction of the arrow N2.

  When both gears 50 and 60 are rotated while meshing with each other, a negative pressure is applied to the suction chamber 84, and the lubricating oil stored in the tank is sucked into the suction chamber 84 through the suction port 91 by this negative pressure. The sucked lubricating oil enters the tooth gaps of both gears 50 and 60 and is sent to the discharge chamber 85 by the rotation of both gears 50 and 60. In this way, the lubricating oil sent from the suction chamber 84 to the discharge chamber 85 is discharged from the discharge chamber 85 through the discharge port 92 to the lubricating oil passage formed in the engine and lubricates each part of the engine. , Returned to the tank.

  Here, in order to rotate the drive shaft 42 smoothly, a clearance is provided between the drive shaft 42 and the rear shaft support portion 83. When the electric oil pump 1 is driven as described above, the lubricating oil sucked and discharged by the pump is interposed between the drive shaft 42 and the rear shaft support portion 83 from both the suction chamber 84 side and the discharge chamber 85 side. Invade the clearance part. The drive shaft 42 is smoothly rotated by the lubricating action of the lubricating oil that has entered the clearance portion.

  At this time, the lubricating oil that has entered the clearance portion between the drive shaft 42 and the rear shaft support portion 83 leaks into the rotor accommodating chamber 31 of the partition case 30. However, since the rotor storage chamber 31 is maintained in a liquid-tight state, the stator 20 including the energization portion (stator coil 22) is not immersed in the lubricating oil leaked into the rotor storage chamber 31. As can be seen from this, the partition case 30 has a function of isolating the lubricating oil leaked into the rotor accommodating chamber 31 from the stator 20. The rotor 40 is rotationally driven in a state where it is immersed in the lubricating oil in the rotor accommodating chamber 31.

  In this case, the lubricating oil leaks from both the discharge chamber 85 and the suction chamber 84 into the rotor accommodating chamber 31 through the clearance. For this reason, the pressure of the lubricating oil filling the rotor accommodating chamber 31 may be increased due to the high pressure on the discharge chamber 85 side. However, the rotor accommodating chamber 31 communicates with the suction chamber 84 through a communication hole 89 having a larger cross-sectional area than the clearance portion. For this reason, the inside of the rotor accommodating chamber 31 is maintained at substantially the same low pressure as the suction chamber 84.

  As a result, it is possible to reduce the pressure strength while maintaining the function of preventing the lubricant from entering the stator 20 that is required for the partition case 30. Since the thickness of the partition case 30 can be reduced according to this low pressure strength, the distance d between the stator 20 and the permanent magnet 43 in the radial direction is reduced by the amount corresponding to the reduced thickness, thereby bringing both closer together. Can be positioned. Therefore, it is possible to efficiently drive the rotor 40 by causing the electromagnetic force generated in the stator 20 to efficiently act on the permanent magnet 43.

  In the above-described embodiment, the example in which the present invention is applied to the electric oil pump 1 configured using the electric motor 2 (synchronous motor) has been described, but the present invention is an electric oil pump configured using an induction motor. It is also applicable to. An example in which the present invention is applied to an electric oil pump 101 configured using an induction motor will be described with reference to FIG. 4 shows a cross section of the induction motor 120 constituting the electric oil pump 101. The electric oil pump 101 includes the oil pump 3 in the same manner as the electric oil pump 1. In the following, the same members as those of the electric motor 2 are denoted by the same reference numerals, and the description thereof is omitted.

  As shown in FIG. 4, a rotor 140 is rotatably disposed at the center of the induction motor 120. The rotor 140 includes a rotor core 141 formed in a substantially cylindrical shape, and four rotor coils 143 provided on the outer periphery of the rotor core 141. The rotor 140 is attached by inserting a drive shaft 142 at the center of the rotor core 141. The rotor coils 143 are provided at positions at equal intervals along the circumferential direction of the rotor core 141. The induction motor 120 also includes a controller 145 that controls energization of the stator coil 22. The controller 45 generates an induced current in the rotor coil 143 by the electromagnetic force generated in the stator coil 22, and controls the energization of the stator coil 22 so that a rotational driving force (inductive force) is applied to the rotor 140 by the induced current. I do.

  In the above-mentioned embodiment, although the example which applied this invention to the electric oil pump 1 comprised using the oil pump 3 which consists of a circumscription meshing type gear pump was demonstrated, it comprises using the oil pump of another form. The present invention can also be applied to an electric oil pump. For example, a trochoid pump configured to include an outer rotor having a sliding surface formed on the inner peripheral side and an inner rotor having a sliding surface formed on the outer peripheral side, or a vane provided so as to protrude into the rotor. The present invention can also be applied to an electric oil pump configured to include a configured vane pump.

  In the above-described embodiment, the configuration example in which the four permanent magnets 43 are attached to the outer peripheral portion of the rotor core 41 and the six stator cores 21 are provided has been described. However, the number of the permanent magnets 43 and the stator cores 21 is not limited thereto. In general, for example, a configuration in which 2n (n is a natural number) permanent magnets 43 are attached to the outer periphery of the rotor core 41 and 3n stator cores 21 are provided is often used. Example of n = 2).

  In the above-described embodiment, the electric oil pump 1 that discharges lubricating oil to the lubricating oil passage of the engine has been described as an example. However, the electric oil pump 1 may include, for example, cooling oil supply, hydraulic supply, and cooling water. It can be used for supply purposes.

1 Electric oil pump (electric pump)
2 Electric motor 3 Oil pump (liquid pump)
10 Motor casing (motor case)
12 Motor compartment (case internal space)
20 Stator 30 Partition case (partition member)
31 Rotor storage chamber (rotor storage space)
40 rotor 42 drive shaft (motor drive shaft)
43 Permanent magnet 89 Communication hole (communication part)
143 Rotor coil (induction coil)

Claims (3)

An electric pump configured by integrally combining a brushless type electric motor and a liquid pump rotated by the electric motor,
The electric motor is provided on a motor case, a motor drive shaft disposed in a case internal space formed inside the motor case and rotatably supported by the motor case, and the motor drive shaft. Extending between the rotor and the stator facing each other, the stator mounted in the motor case located in the inner space of the case so as to face and surround the rotor from the outside in the circumferential direction A partition member that partitions the internal space of the case into a rotor side space in which the motor drive shaft and the rotor are disposed and a stator side space in which the stator is disposed;
The motor drive shaft passes through the motor case and is integrally connected to the pump drive shaft of the liquid pump, and the rotation of the motor drive shaft is transmitted to the pump drive shaft.
An electric pump characterized in that a communication portion is provided for communicating the rotor side space with the suction side of the liquid pump. The rotor is configured with a permanent magnet on the outer periphery,
2. The electric pump according to claim 1, wherein the electric pump is configured to perform energization control on the stator to perform rotation control of the motor drive shaft via the rotor. The rotor is configured to have an induction coil on the outer periphery,
2. The electric motor according to claim 1, wherein energization control of the stator is performed and control is performed to rotationally drive the motor drive shaft using an induction force generated in the induction coil. 3. pump.

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