JP2014034878A - Pump for liquid refrigerant circulation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pump for a liquid refrigerant circulation, which has an outer gear and so on shaped in a cylinder with a bottom and still prevented from inclination during operation, thereby preventing generation of abrasion, vibration, and noise caused by increase of a friction coefficient of the gear.SOLUTION: A pump 1 circulating liquid refrigerant in a refrigerant circuit, includes: a main body 2 including a cylindrical gear accommodation chamber 2a having a bottom portion, and a suction port 2d and a discharge port 2e each opening in the gear accommodation chamber; an outer gear 4 rotatably arranged in the gear accommodation chamber; an inner gear 3 which has external teeth meshing with the internal teeth of the outer gear, and a rotational axis of which is provided eccentrically from a rotational axis of the outer gear; a motor 6 discharging liquid refrigerant from the suction port to the discharge port by rotating the outer gear; and a magnetic coupling 5 connecting the outer gear and a drive shaft 6a of the motor. The outer gear has a through hole 4c positioned between the adjacent internal teeth and close to a bottom portion of the gear accommodation chamber, and penetrating between an inner and an outer surface of the outer gear.

Description

  The present invention relates to a liquid refrigerant circulation pump, and more particularly to a liquid refrigerant circulation pump used for cooling a heating element such as an electric motor or an inverter of an electric vehicle or a hybrid vehicle with a liquid refrigerant of an air conditioner.

  In an electric vehicle or a hybrid vehicle, it is necessary to cool a heating element such as a motor or an inverter. For example, in the invention described in Patent Document 1, the heating element is cooled using an air conditioner (vapor compression refrigeration cycle). At this time, when an internal gear pump is used as a means for supplying the refrigerant to the heating element, since the power supply system of the vehicle on which the pump is mounted is diverse, the pump and the pump driving motor can be separated. It is desirable.

  Therefore, the present applicant has already adopted an internal gear pump as a pump and an invention in which an outer gear is used as a driving side gear and the outer gear and a gear driving motor are connected via a magnetic coupling. An application has been filed (Japanese Patent Application No. 2012-130612 (filed on June 8, 2012)). According to the present invention, the outer gear has a bottomed cylindrical shape, and a magnet for magnetic coupling is provided at the bottom of the outer gear so as to enter the inner tooth side of the gear, thereby reducing the size of the pump (smaller outer dimensions). ing.

  By the way, in the internal gear pump, fluid is sucked into and discharged from the space due to the expansion and contraction of the space formed between the outer gear and the inner gear that rotate while meshing with each other. Due to the pressure difference between the discharge portion and the discharge portion, a corner force (positive and negative force) acts on the outer gear, the outer gear tilts, the friction coefficient of the gear increases, and wear, vibration, and noise tend to occur. In order to eliminate such a problem, Patent Document 2 discloses a technique for forming a pressure balance groove around the lower surface of the outer gear.

Japanese Patent No. 3591304 JP 2002-5039 A

  The pressure balance grooves formed around the lower surface of the outer gear described in Patent Document 2 can effectively balance the forces acting on both side surfaces of the outer gear, but are described in Japanese Patent Application No. 2012-130612. In the case of the outer gear formed in a bottomed cylindrical shape as described above, there is a problem that it cannot be adopted.

  Further, as described in the above-mentioned prior application (Japanese Patent Application No. 2012-130612), when the outer gear has a bottomed cylindrical shape, the refrigerant is discharged only from the upper opening of the outer gear, and the refrigerant is retained at the bottom. Therefore, the refrigerant discharge side opening (top) of the outer gear and the bottom of the outer gear corresponding to the opening (that is, the bottom located on the opposite side of the opening in the direction parallel to the central axis of the outer gear) There is a possibility that a pressure difference occurs between the outer gear and the outer gear.

  Therefore, the present invention prevents the outer gear or the like formed in a cylindrical shape with a bottom from tilting during operation, and prevents the occurrence of wear, vibration, and noise accompanying an increase in the friction coefficient of the gear. An object of the present invention is to provide a liquid refrigerant circulation pump capable of performing

  In order to achieve the above object, the present invention is a pump for circulating a liquid refrigerant in a refrigeration cycle, comprising a cylindrical gear housing chamber having a bottom, and an intake port and a discharge port that open to the gear housing chamber. A main body having an inner tooth, an outer gear rotatably disposed in the gear housing chamber, and an outer tooth meshing with an inner tooth of the outer gear, the rotation axis of which rotates the outer gear An inner gear provided to be eccentric from the axis, a motor that discharges liquid refrigerant from the suction port to the discharge port by rotating the outer gear, and a magnet that connects the outer gear and the drive shaft of the motor The outer gear is located between adjacent inner teeth of the outer gear, and penetrates between the inner surface and the outer surface of the outer gear at the lower portion of the outer gear. Characterized in that it comprises a hole.

  According to the present invention, since the through-hole penetrating between the inner surface and the outer surface of the outer gear is provided between adjacent inner teeth of the outer gear and at the lower portion of the outer gear, A part of the liquid refrigerant sucked into the gap between the inner teeth and the outer teeth of the inner gear flows out from the lower portion of the outer gear through the through hole of the outer gear. As a result, the pressure of the liquid refrigerant retained at the bottom in the gap can be released, and the pressure difference between the refrigerant discharge side opening of the outer gear and the bottom of the outer gear corresponding to the opening can be kept small. Can do. As a result, it is possible to effectively prevent the outer gear from being inclined, and it is also possible to discharge the wear powder of the inner gear, dust, slime and the like that have entered the gap to the outside of the gear housing chamber.

  In the liquid refrigerant circulation pump, the tooth surfaces of the outer gear and the inner gear can be formed so as to have a cycloid tooth profile, and by using the cycloid tooth profile, the discharge capacity can be increased as compared with the case where an involute tooth profile is used. Can be bigger.

  The refrigeration cycle is used in a vehicle air-conditioning system, can cool a heating element of the vehicle with the liquid refrigerant, and can provide a pump with good vehicle mountability.

  As described above, according to the present invention, even an outer gear or the like formed in a bottomed cylindrical shape is prevented from being tilted during operation, and wear, vibration, and noise associated with an increase in the coefficient of friction of the gear. It is possible to provide a liquid refrigerant circulation pump capable of preventing the occurrence of the above.

It is a whole lineblock diagram showing the refrigerating cycle system provided with the liquid refrigerant circulation pump concerning the present invention. It is a front view which shows the pump for liquid refrigerant circulation which concerns on this invention. It is a top view which shows the pump for liquid refrigerant circulation which concerns on this invention. It is a bottom view which shows the pump for liquid refrigerant circulation which concerns on this invention. It is the sectional view on the AA line of the liquid refrigerant circulation pump shown in FIG. It is a BB sectional view of the liquid refrigerant circulation pump shown in FIG. It is CC sectional view taken on the line of the liquid refrigerant circulation pump shown in FIG. It is a perspective view which shows the outer gear of the pump for liquid refrigerant circulation which concerns on this invention, Comprising: (a) shows the state seen from the downward | lower direction, (b).

   Next, embodiments for carrying out the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows a refrigeration cycle system provided with a liquid refrigerant circulation pump (hereinafter referred to as “pump”) according to the present invention. This system 101 includes a compressor 102, a condenser 103, an expansion valve 104, An evaporator 105 and the pump 1 according to the present invention are provided, and the pump 1 is used to cool a heating element 107 such as an electric motor or an inverter of an electric vehicle or a hybrid vehicle.

  The compressor 102, the condenser 103, the expansion valve 104, and the evaporator 105 are connected by a pipe 109, and the refrigerant circulates between them. Further, the liquid refrigerant flows through the bypass pipe 110 that connects the pipe 109 between the condenser 103 and the expansion valve 104 and the pipe 109 between the compressor 102 and the condenser 103.

  The pump 1 is an inscribed gear pump, and as shown in FIGS. 2 to 7, the main body 2 having the gear housing chamber 2a and the inner side of the gear housing chamber 2a are substantially slidably disposed so as to be rotatable. The outer gear 4 has outer teeth that mesh with the inner teeth of the outer gear 4, rotates eccentrically from the rotation axis of the outer gear 4, and rotates the outer gear 4 via the magnetic coupling 5. The motor 6 etc. to be made up.

  In the main body 2, an outer gear 4 and an inner gear 3 are accommodated in an internal gear accommodating chamber 2a, and an O-ring 12 for ensuring airtightness when a cover (not shown) is attached is disposed on the upper portion. . Further, an O-ring 13 is mounted between the lower surface of the main body 2 and the partition plate 20 to ensure airtightness inside the main body 2, and the main body 2, the partition plate 20 and the motor mounting portion 8 are connected to the bolts 14. Bound by ~ 17. Partition plate 20 constitutes the bottom of gear housing chamber 2a.

  The main body 2 is formed with a refrigerant inlet 2b, a suction port 2d communicating with the refrigerant inlet 2b, a discharge port 2e, and a refrigerant outlet 2c communicating with the discharge port 2e, which communicate with the gear housing chamber 2a. To do. The refrigerant inlet 2b is connected to the pipe 109 side of FIG. 1 through a cover, the refrigerant outlet 2c is connected to the heating element 107 side, and the cover is fixed to a bracket or the like.

  The main body 2 includes a support shaft 2g extending from the top toward the bottom surface of the gear housing chamber 2a. The support shaft 2g has two rotational axes that are eccentric, and supports the inner gear 3 rotatably at the upper part and supports the outer gear 4 via a bearing 9 at the lower part. The upper and lower structures of the support shaft 2g are reversed, and the support shaft 2g extends from the bottom of the gear housing chamber 2a toward the lower surface of the main body 2 by disposing the bearing 9 on the upper portion of the gear housing chamber 2a. It can also be established.

  In this example, the refrigerant inlet 2b is opened on the upper surface of the main body 2, and the refrigerant outlet 2c is opened on the side surface of the main body 2. However, the refrigerant inlet 2b is opened on the side surface of the main body 2, and the refrigerant outlet 2c is opened on the upper surface of the main body 2. Even if it carries out, both the refrigerant | coolant inlet 2b and the refrigerant | coolant outlet 2c can also be provided in the upper surface of the main body 2, or can also be provided in a side surface.

  The inner gear 3 has an external tooth profile formed by a cycloid curve, and a hole formed in the center thereof is rotatably inserted into the upper portion (large diameter portion 2x) of the support shaft 2g of the main body 2.

  The outer gear 4 has an inner tooth profile formed by a cycloid curve, and is rotatably supported by a bearing 9 formed of resin at a lower portion thereof. The bearing 9 is press-fitted into a hole formed in the bottom center of the outer gear 4 and is rotatably inserted into the lower end portion (small diameter portion 2y) of the support shaft 2g of the main body 2, whereby the outer gear 4 has a small diameter. The part 2y is rotatably supported. The outer gear 4 includes a magnet 4b on the bottom surface of the bottomed cylindrical main body 4a. The outer gear 4 forms a magnetic coupling 5 together with the magnet 6b on the motor 6 side, and rotates within the gear housing chamber 2a. The magnet 4b is caulked and fixed by the claw portion 4e of the lower protruding portion 4d shown in FIG.

  Further, as clearly shown in FIG. 8, a through hole 4c is formed in the lower part of the main body 4a between adjacent inner teeth of the outer gear 4, and the inside of the gear housing chamber 2a is formed through the through hole 4c. Communicates with the outside. In this example, the through hole 4c is formed so as to open to the inside of the main body 4a and its lower side surface and bottom surface, but only the inside of the main body 4a and its lower side surface, or only the inside and bottom surface of the main body 4a. You may make it open to.

  As described above, the inner gear 3 and the outer gear 4 are inscribed gears whose teeth are formed by a cycloid curve. Since the central axes of these gears 3 and 4 are eccentric, the relative rotation of these gears 3 and 4 causes the gap G generated between the two gears 3 and 4 in the gear housing chamber 2a to repeatedly expand and contract.

  Here, as shown in FIG. 7, if the outer gear 4 is rotated in the direction of the arrow R, the suction port 2d opens into the expansion region of the gap G between the inner gear 3 and the outer gear 4, while the discharge port 2e is opened to the contraction region of the gap G, so that the refrigerant is sucked into the gap G between the gears 3 and 4 through the refrigerant inlet 2b and the suction port 2d by the relative rotation of both the gears 3 and 4. The sucked refrigerant is discharged from the discharge port 2e and the refrigerant outlet 2c. In addition, the tooth profile of the inner gear 3 and the outer gear 4 can also be formed by an involute curve.

  The motor 6 is attached to the motor attachment portion 8 via a bolt 21 and a magnet 6b is attached to the drive shaft 6a. In this state, the motor attachment portion 8 and the main body 2 are fastened by bolts 15 and 16. Thereby, the magnet 6b and the magnet 4b face each other with the partition plate 20 interposed therebetween, and the magnetic coupling 5 that connects the outer gear 4 and the motor 6 is configured.

  When the motor 6 rotates, the pump 1 having the above configuration rotates around the support shaft 2g while the outer gear 4 meshes with the inner gear 3 via the magnetic coupling 5. The engagement between the inner gear 3 and the outer gear 4 changes the volume of the gap G between the two gears 3 and 4 in the gear housing chamber 2a as clearly shown in FIG. The liquid refrigerant sucked from the pipe 109 shown in FIG. 1 flows into the gear housing chamber 2a through the port 2d and flows to the refrigerant outlet 2c through the gear housing chamber 2a and the discharge port 2e. The liquid refrigerant discharged from the refrigerant outlet 2 c is supplied to the heating element 107 in FIG. 1 to cool the heating element 107.

  Here, due to the expansion and contraction of the gap G formed between the rotating outer gear 4 and the inner gear 3, fluid is sucked into and discharged from the gap G. The refrigerant in the suction port 2d and the discharge port 2e Corner force acts on the outer gear 4 due to the pressure difference. However, since the outer gear 4 is supported by the small diameter portion 2y of the support shaft 2g via the bearing 9, it is possible to prevent the outer gear 4 from being inclined due to corner force. As a result, it is possible to prevent the occurrence of wear, vibration, and noise associated with increased friction of the outer gear 4 and the inner gear 3.

  Further, as clearly shown in FIG. 5, since the discharge port 2e is a narrow refrigerant flow path, the flow rate of the refrigerant passing through the discharge port 2e from the gap G increases and the refrigerant pressure decreases. A plurality of through holes 4c are formed in the lower part of the gear 4, and the refrigerant in the gap G is also discharged from the through holes 4c, so that the refrigerant of the outer gear 4 is compared with the case where the through holes 4c are not formed. Pressure difference generated between the upper side and the lower side on the discharge side (that is, the opening on the discharge port 2e side of the rotating outer gear 4 and the opening opposite to the opening in a direction parallel to the central axis of the outer gear) (Corresponding pressure difference with the bottom) is reduced, and this can also prevent the outer gear 4 from tilting.

  Further, since the through-hole 4c is provided, it becomes possible to discharge the abrasion powder of the inner gear 3, dust, slime, and the like that have entered the gap G to the outside of the gear housing chamber 2a.

  In the above description, the outer gear 4 is rotatably supported by the lower end portion of the support shaft 2g via the bearing 9 provided at the bottom thereof, but the present invention is particularly limited to this. However, the outer gear 4 may be disposed so as to be rotatable in contact with the inner side of the gear housing chamber 2a without using a bearing.

  Moreover, in the said embodiment, although the inner gear 3 and the outer gear 4 were supported by the one support shaft 2g, the support shaft of the inner gear 3 and the outer gear 4 can also be provided separately.

  Further, the pump 1 has been described as supplying the liquid refrigerant in the refrigeration cycle to the heating element in order to cool the heating element such as an electric motor or an inverter of an electric vehicle or a hybrid vehicle. In particular, it is not limited to this, and it can be used for the circulation of the refrigerant itself to the condenser, evaporator, etc. of the refrigeration cycle.

DESCRIPTION OF SYMBOLS 1 Liquid refrigerant circulation pump 2 Main body 2a Gear accommodation chamber 2b Refrigerant inlet 2c Refrigerant outlet 2d Suction port 2e Discharge port 2g Support shaft 2x Large diameter part 2y Small diameter part 3 Inner gear 4 Outer gear 4a Main body 4b Magnet 4c Through-hole 4d Lower protrusion Part 4e Claw part 5 Magnetic coupling 6 Motor 6a Drive shaft 6b Magnet 8 Motor mounting part 9 Bearing 12, 13 O-ring 14-17 Bolt 20 Partition plate 21 Bolt 101 Refrigeration cycle system 102 Compressor 103 Condenser 104 Expansion valve 105 Evaporation 107 Heating element 109 Piping 110 Bypass pipe

Claims (3)

A pump for circulating liquid refrigerant in the refrigeration cycle,
A cylindrical gear housing chamber having a bottom, and a main body having a suction port and a discharge port that open to the gear housing chamber;
An outer gear having inner teeth and rotatably disposed in the gear housing chamber;
An outer gear having external teeth meshing with the inner teeth of the outer gear, and an inner gear provided such that its rotational axis is eccentric from the rotational axis of the outer gear;
A motor that discharges liquid refrigerant from the suction port to the discharge port by rotating the outer gear;
A magnetic coupling for connecting the outer gear and the drive shaft of the motor;
The outer gear is provided with a through-hole that passes between an inner surface and an outer surface of the outer gear at a lower portion of the outer gear between adjacent inner teeth of the outer gear. Circulation pump.   The liquid refrigerant circulation pump according to claim 1, wherein tooth surfaces of the outer gear and the inner gear have a cycloid tooth profile.   3. The liquid refrigerant circulation pump according to claim 1, wherein the refrigeration cycle is used in an air conditioning system for a vehicle, and a heating element of the vehicle is cooled by the liquid refrigerant.

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