JP2012149603A - Electric pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicular electric pump wherein an electric motor is integrally combined with a pump, and which has a structure for efficiently cooling heat generated in a motor unit and a circuit section.SOLUTION: This electric pump includes: a pump unit 1 having a liquid feeder; the motor unit 2 constituted of a shaft 22 driving the pump unit 1, a motor rotor 23 firmly fixed with the shaft 22, and a motor housing 21 having air intake holes 211; the circuit section 3 having a circuit board 32 formed with flowing-through holes 321; a heat sink 4 installed to the circuit section 3, and formed with a large number of projection shaft-like fins 42; and a fan 24 installed to the motor unit 2. In a state that the electric pump is installed with the axial direction of the shaft 22 as a horizontal direction, at least one of the fins 42 in a lower area of the heat sink 4 than the shaft 22 is formed with an exhaust hole 43, and air flows through the exhaust hole 43 from the air intake holes 211 via the flowing-through holes 321 by rotation of the fan 24.

Description

  The present invention relates to an electric pump for a vehicle provided with a structure for efficiently cooling heat generated by a motor part and a circuit part in an electric motor combined with a pump.

  As a rotating electrical machine having a cooling mechanism, Patent Document 1 exists. In the configuration disclosed in Patent Document 1, the rotor 6 is rotatably disposed inside the case 3 via the shaft 22, and is disposed inside the case 3 so as to surround the outer periphery of the rotor 6. Heater elements (16, 20) that are attached to the stator 8, the element mounting surface 13a of the heat sink 13, and electrically control the rotation of the rotor 6, and the intake holes 2a and exhaust holes 2b drilled in the case 3 And a fan 7 that is fixed to the axial end surface of the rotor 6, rotates with the rotor 6, sucks air into the case 3 through the intake holes 2a, and generates a flow of cooling air that exhausts out of the case 3 through the exhaust holes 2b. And.

  A large number of ventilation holes (30a, 30b, 30c) having a circular cross section are parallel to each other and parallel to the element mounting surface 13a from the intake side opening surface (13b, 15b) to the exhaust side opening surface ( 13c, 15c) is formed in the heat sink 13. Furthermore, the heat sink 13 is disposed with the intake side opening surfaces (13b, 15b) facing the intake holes 2a and the direction of the ventilation holes (30a, 30b, 30c) aligned with the flow direction of the cooling air. Has been. Furthermore, the heat sink 13 is formed so that the passage cross-sectional area of the cooling air orthogonal to the hole direction is larger on the downstream side than the upstream side in the flow direction of the cooling air.

JP2007-68299A

  The configuration of the invention disclosed in Patent Document 1 has the following problems. A large number of ventilation holes (30a, 30b, 30c) having a circular cross section are formed in the heat sink 13. And, in order to increase the heat dissipation effect of the heat sink, trying to increase the length of a large number of ventilation holes (30a, 30b, 30c) having a circular cross section in order to increase the contact area, the heat sink 13 becomes inevitably larger and heavier. End up. In order to mount the device on the vehicle, it is necessary to limit the size and weight to a predetermined value or less, and therefore, the heat dissipation effect has a limit.

  Further, as described in FIG. 1 of Patent Document 1, since the exhaust hole 2b is opened upward, foreign matters such as water and sand are likely to enter. If water, sand, or the like enters the rotating electrical machine, there is a risk of electric leakage or defective rotation, so it is necessary to avoid it as much as possible. Since the ventilation hole 30a arranged in the upper left of FIG. 1 in Patent Document 1 is opened through the heat sink 13 in the horizontal direction, the water and sand that have entered through the ventilation hole 30a are alone (left to stand naturally). Also, it is not discharged out of the motor housing.

  On the contrary, since the wind flows in the ventilation hole 30a toward the motor by the fan 7, the water and sand remaining in the ventilation hole 30a move into the motor and cause a failure of the motor. Therefore, the problem (technical problem) to be solved by the present invention is that the heat generated from the motor part and the circuit part is efficiently cooled by a very simple configuration, the manufacturing cost is reduced, and the entire apparatus is made compact. There is to do.

Therefore, as a result of intensive studies and researches to solve the above problems, the inventor devised the invention of claim 1,
A pump unit having a liquid feeding means, a motor unit comprising a shaft for driving the pump unit, a motor rotor to which the shaft is fixed, and a motor housing having an intake hole, and a circuit unit having a circuit board in which a flow hole is formed And a heat sink attached to the circuit part and formed with a number of protruding shaft-like fins, and a fan attached to the motor part, in a state where the axial direction of the shaft is set as a horizontal direction, An electric pump in which an exhaust hole is formed in one of the fins in a lower region of the heat sink than the shaft, and air flows from the intake hole to the exhaust hole through the flow hole by rotation of the fan; As a result, the above problems were solved.

  According to a second aspect of the present invention, in the first aspect, the fin in which the exhaust hole is formed has a slit extending in the axial direction, and the motor is divided radially through the slit in the diameter direction of the fin. The above problem was solved by using a pump. According to a third aspect of the present invention, in the first or second aspect, the above-described problem is solved by using an electric pump in which the flow hole of the circuit board is disposed in the vicinity of the power element.

  According to the first aspect of the present invention, the motor housing of the motor portion is formed with an air intake hole, the circuit board of the circuit portion is formed with a flow hole, and the heat sink is formed with a number of fins having a protruding shaft shape. In addition, an exhaust hole is formed in one of the fins, and the intake hole and the exhaust hole are configured to allow air to flow through the flow hole. Furthermore, the cooling efficiency of the heat sink is improved by forming the exhaust holes by forcing the air flow from the intake holes toward the exhaust holes by the fan mounted on the motor unit and rotating with the shaft. Can do.

  In particular, since the exhaust hole is formed in one of a large number of fins, a large contact area between the heat sink and the air can be secured, and the area of the heat sink is not increased. can do. Further, since the exhaust hole is formed in the fin, the exhaust hole itself is protected by the fin, and the exhaust hole is a hole on the side from which the air is exhausted. It has a structure in which foreign matter such as water and sand cannot easily enter from the hole. Therefore, the circuit board inside the electric pump can be protected.

  Further, since the exhaust hole is formed in any or all of the fins in the lower region of the heat sink with respect to the shaft in a state where the axial direction of the shaft of the motor unit is arranged in the horizontal direction, the present invention When the shaft of the electric pump is horizontal, the air exhausted from the exhaust hole rises and the fins in the upper area of the heat sink are cooled by the flow of exhaust air, further improving the cooling efficiency of the heat sink itself There are advantages that can be made.

  In the invention according to claim 2, the fin in which the exhaust hole is formed has a structure in which a slit extending in the axial direction is formed, and the fin is radially divided through the slit in the diameter direction of the fin. Since the air discharged from the air passes between the slits, the contact area between the air and the heat sink can be increased. Therefore, the heat dissipation effect is further enhanced.

  Furthermore, because the fins are divided radially through the slits, the air discharged from the exhaust holes flows radially from the fins, and not only the fins with the exhaust holes formed, but also the air around them. It is possible to form a uniform air flow on the outer surface of the heat sink, and to have excellent cooling performance. In the invention of claim 3, cooling of the power element that generates particularly high heat can be promoted by adopting a configuration in which the flow hole of the circuit board is disposed in the vicinity of the power element.

(A) is a longitudinal side view showing the configuration of the present invention, (B) is a view taken along arrow Y1-Y1 in (A), (C) is an enlarged view of part (A) in (B), and (D) is (C It is a Y2-Y2 arrow expanded sectional view of). (A) is a perspective view of a motor rotor and a fan mounted on the motor rotor, (B) is a vertical side view of another type of motor rotor and a fan mounted on the motor rotor, and (C) is a view taken along arrow Y3-Y3 in (B). FIG. (A) is the perspective view which partially cut away 1st Embodiment of a fin, (B) is a perspective view of 2nd Embodiment of a fin. (A) is the front view which partially cut away 3rd Embodiment of a fin, (B) is the front view which partially cut off the modification of 3rd Embodiment of a fin. (A) is an enlarged vertical sectional side view of the main part showing a state in which air is discharged from the circulation hole and the exhaust hole by the fan in the present invention, and (B) is an enlarged view as seen from the arrow Y4-Y4.

  The present invention will be described below with reference to the drawings. The present invention is an electric pump, and as shown in FIG. 1 (A), is composed of a pump part 1, which is mainly used as an oil pump, a motor part 2, a circuit part 3, and a heat sink 4. The pump unit 1, the motor unit 2, the circuit unit 3, and the heat sink 4 are connected in this order along the direction. In principle, the electric pump of the present invention is installed at a predetermined position of the vehicle body so that the axial direction of the shaft 22 described later is horizontal.

  The pump unit 1 includes a pump case 11, a drive rotor 12, a driven rotor 13, and an oil seal 14. A rotor chamber 11a is formed in the pump case 11, a bearing hole 11b is formed at a position near the center of the rotor chamber 11a, and a suction port 11c and a discharge port 11d are substantially symmetrical about the bearing hole 11b. And are formed. The drive rotor 12 and the driven rotor 13 employ an internal gear type rotor (see FIG. 1A). Although not particularly illustrated, an external gear type rotor in which the drive rotor 12 and the driven rotor 13 are combined with external gears may be employed.

  In the present invention, as shown in FIG. 1 (A), the drive rotor 12 and the driven rotor 13 will be described as using an internal gear type. Therefore, an inner rotor is used for the drive rotor 12, and an outer rotor is used for the driven rotor 13. The drive rotor (inner rotor) 21 has a plurality of trochoidal outer teeth, and the driven rotor (outer rotor) 22 has one or more internal teeth more than the drive rotor 12. The outer teeth of the rotor 12 and the inner teeth of the driven rotor 13 continue to rotate while being in smooth contact.

  A gap formed by the external teeth of the drive rotor 12 and the internal teeth of the driven rotor 13 is referred to as an interdental space S (cell). A boss hole is formed in the rotation center of the drive rotor 12, and the shaft 22 of the motor unit 2 is inserted. The drive rotor 12 and the shaft 22 are fixed in the circumferential direction with a key or the like so as to rotate together. . The pump case 11 is formed with a recess for mounting the oil seal 14, and the oil seal 14 mounted on the pump case 11 has the oil leaking through the gap between the pump case 11 and the shaft 22. It plays a role of preventing leakage to the motor unit 2 side.

  The motor unit 2 includes a motor housing 21, a shaft 22, a motor rotor 23, a fan 24, and a stator 25. The motor housing 21 is formed in a hollow cylindrical shape, is formed of a mold resin described later, and is formed so as to cover the stator 25. In principle, the electric pump of the present invention is installed so that the axial direction of the shaft 22 is horizontal, and for this purpose, the motor housing 21 is installed so that the axial direction thereof is horizontal.

  Therefore, the motor housing 21 has a vertical direction in the diametrical direction. Basically, with the electric pump attached to the vehicle, the upper side in the diametrical direction of the motor housing 21 is the upper part and the lower part in the diametrical direction is the lower part. To do. An intake hole 211 that penetrates in the vertical direction is formed on the lower side (lower end) of the motor housing 21. The intake hole 211 is a small diameter hole having a diameter of about several mm. Further, it may be formed at any position on the lower side along the axial direction of the motor housing 21. Specifically, the intake hole 211 is formed closer to the connection side with the pump case 11 in the axial direction of the motor housing 21, thereby improving the cooling efficiency.

  Further, the shape of the intake hole 211 may be a substantially semicircular shape, and may be formed as a notch-shaped recess at the axial end of the motor housing 21. In this case, by joining the motor housing 21 to the pump case 11, a substantially through-hole-like intake hole 211 can be formed. The notch-shaped intake hole 211 has a simple shape and is easy to manufacture. An intake hole 211 formed in the motor housing 21 is a through hole that takes in air for radiating heat inside the motor housing 21, and is formed on the lower side of the motor housing 21 so that foreign matters such as water and sand It is possible to make it difficult to enter the inside of the motor unit 2.

  The hole passage direction in which the intake hole 211 is formed is arranged vertically with respect to the motor housing 21 with the electric pump attached to the vehicle. As a result, foreign matter such as water and sand rises in the intake hole 211 and is difficult to enter the motor housing 21. Even if foreign matter such as water or sand enters the motor housing 21 from the intake hole 211, the intake hole 211 is formed at the lowermost part of the motor housing 21. Foreign matter such as water and sand entering the motor housing 21 can be easily discharged from the suction port.

  One end of the shaft 22 in the axial direction is fixed to a motor rotor 23 to be described later, and the other end in the axial direction extends to the pump chamber 11 of the pump unit 1 so that the drive rotor 12 can be rotationally driven. It is configured. As described above, the electric pump of the present invention is installed with respect to the vehicle body so that the shaft 22 is a reference, and the axial direction thereof is horizontal (including not only a strict horizontal direction but also a substantially horizontal direction).

  The motor rotor 23 includes a rotor base 231 and a rotor magnet 232. The rotor base 231 has a substantially cup shape and includes a bottom portion 231a and a cylindrical side portion 231b. The bottom portion 231a is formed in a disk shape, and the shaft end portion of the shaft 22 is fixed to the center of the diameter. The rotor magnet 232 has a cylindrical shape and is attached to the cylindrical side portion 231 b of the rotor base 231.

  The shaft 22 is attached to the bottom 231a of the rotor base 231 by means such as press fitting. In the motor rotor 23, when the rotor magnet 232 is a sintered magnetic body, it is called a sintered rotor. Further, the rotor magnet 232 may be formed as a plastic magnet. Such a motor rotor 23 is referred to as a resin rotor.

  The rotor magnet 232 of the motor rotor 23 is positioned and rotated on the inner peripheral side of the stator 25 described later, and the gap between the outer periphery of the rotor magnet 232 and the inner periphery of the stator 25 is several mm. The rotor magnet 232 is rotated by the magnetic force of the stator 25, and the motor rotor 23 and the shaft 22 are rotated by the rotor magnet 232, thereby exhibiting a function as a pump.

  The fan 24 rotates with the rotation of the motor rotor 23, and serves to circulate the air sucked from the intake hole 211 of the motor housing 21 toward the exhaust hole of the heat sink 4 to be described later. In the fan 24, a plurality of blades 242, 242,... Are formed at equal intervals on the outer peripheral side surface of the disc-shaped rotation base 241. These are integrally formed by resin molding [FIG. See A)].

  The fan 24 may be formed of a sintered body or the like from a mold. The fan 24 is provided at the bottom 231a of the rotor base 231. Specifically, one end in the axial direction of the rotor base 231 fixed to the shaft 22 is formed to protrude outward from the bottom portion 231a, and the fan 24 is fixed to the protruding portion of the shaft 22. That is, when the motor rotor 23 is rotated, the shaft 22 is rotated, and the fan 24 is rotated by the rotation of the shaft 22 (see FIG. 1A).

  Further, as another embodiment of the fan 24, a plurality of blades 242, 242,... For forming the fan 24 between the shaft 22 and the cylindrical side portion 231b at the bottom 231a of the rotor base 231, and the blades 242 , 242,... And vent holes 243, 243,... Are formed (see FIGS. 2B and 2C). The fan 24 rotates as the bottom portion 231a rotates with the rotation of the rotor base 231. The stator 25 is mounted on the inner peripheral side of the motor housing 21.

  In the circuit unit 3, a circuit board 32 is mounted on a circuit housing 31. A power element 33 that controls and drives the stator 25 is mounted on the circuit board 32. The power element 33 is a semiconductor element that actually sends electricity to the coil based on the calculation result of the element that detects the phase of the motor rotor 23 and calculates how to energize each coil. A circulation hole 321 is formed in the circuit board 32 (see FIG. 1A). The flow hole 321 serves to perform air flow between the motor unit 2 and a heat sink 4 described later. The flow hole 321 is formed in the vicinity of the power element 33. Thereby, air forcibly flows in the vicinity of the power element 33, and more heat generated from the power element 33 can be radiated.

  The heat sink 4 is made of a metal having good thermal conductivity (easy to transmit heat) such as an aluminum alloy, and includes a base plate 41 and a large number of fins 42, 42,. The base plate 41 has a substantially disk shape. The fins 42 are formed in a protruding shaft shape, specifically, a cylindrical columnar shape. The heat sink 4 is connected to the circuit housing 31. The base plate 41 of the heat sink 4 is mounted on the motor housing 21 so as to be orthogonal to the axial direction of the shaft 22 of the motor unit 2, and the electric pump is basically arranged so that the axial direction of the shaft 22 is horizontal. In the installed state, the lower region with reference to the shaft 22 of the base plate 41 is referred to as a lower region Sd, and the upper region is referred to as an upper region Su (see FIGS. 1A and 1B).

  An exhaust hole 43 is formed in any one of a large number of fins 42, 42,... Formed in the lower region Sd of the base plate 41. The exhaust hole 43 penetrates the base plate 41 and exhausts air forcedly blown by the fan 24 through the fins 42 to the outside. Since the air directly touches the fins 42 in the process of discharging through the exhaust holes 43, the cooling efficiency of the heat sink 4 is further improved.

  The fins 42 having the exhaust holes 43 are formed as small cylindrical columns with axial protrusions in a direction perpendicular to the plate surface of the base plate 41. Further, the fin 42 is formed with a plurality of slits 421, 421,... Along the axial direction on the peripheral wall of the cylindrical portion. That is, the fin 42 is divided by the slit 421. Specifically, there are a plurality of embodiments, and in the first embodiment, four slits 421 are formed at equal intervals [see FIGS. 1C and 3A]. That is, the slits 421 are formed at a total of four positions every 90 degrees, so that the peripheral wall of the fin 42 is formed as four arc-shaped blocks.

  As described above, by forming a plurality of slits 421 along the axial direction in the fin 42, the air discharged from the exhaust hole 43 comes into contact with the heat sink 4 in a larger area, so that the heat dissipation effect is enhanced. In other words, since air also flows from the exhaust hole 43 to the slit 421, the air discharged by the surface area of the slit 421 contacts the heat sink in a larger area, so that the heat dissipation effect is enhanced.

  Next, as a second embodiment of the fin 42, there is a type in which two slits 421 are formed [see FIG. 3B]. In this embodiment, the fins 42 are separated into two arcuate blocks. Further, as a third embodiment of the fin 42, there is a type in which three slits 421 are formed (see FIG. 4). In this type, the peripheral wall of the fin 42 is separated into three arc-shaped blocks. Water from the outside has an effect of making it difficult to enter due to surface tension by the slit 421.

  Thus, the fins 42, 42, formed in the region (lower region Sd) located below the shaft 22 of the heat sink 4 with the electric pump according to the present invention installed in a state where the axial direction of the shaft 22 is horizontal. By providing the exhaust holes 43 in any of the above, the air discharged from the exhaust holes 43 is discharged radially in the diameter direction of the fins 42 and is radiated by the surrounding fins 42, 42,. The cooling efficiency can be improved (see FIGS. 1A and 5).

DESCRIPTION OF SYMBOLS 1 ... Pump part, 2 ... Motor part, 21 ... Motor housing, 211 ... Intake hole,
22 ... Shaft, 23 ... Motor rotor, 24 ... Fan, 3 ... Circuit part,
32 ... Circuit board, 321 ... Distribution hole, 33 ... Power element, 4 ... Heat sink,
42 ... fin, 43 ... exhaust hole, 421 ... slit.

Claims (3)

  A pump unit having a liquid feeding means, a motor unit comprising a shaft for driving the pump unit, a motor rotor to which the shaft is fixed, and a motor housing having an intake hole, and a circuit unit having a circuit board in which a flow hole is formed And a heat sink attached to the circuit part and formed with a number of protruding shaft-like fins, and a fan attached to the motor part, in a state where the axial direction of the shaft is set as a horizontal direction, An exhaust hole is formed in one of the fins in the lower region of the heat sink than the shaft, and air is circulated from the intake hole to the exhaust hole through the flow hole by rotation of the fan. Electric pump.   2. The electric pump according to claim 1, wherein the fin in which the exhaust hole is formed has a slit extending in an axial direction and is radially divided through the slit in a diameter direction of the fin.   3. The electric pump according to claim 1, wherein the flow hole of the circuit board is disposed in the vicinity of the power element.

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