DRIVING PART FOR VARIABLE-CAPACITY COMPRESSOR

Abstract

The drive unit has an effect of maintaining controllability and preventing a hunting problem caused under low flow conditions since it includes a friction ring module.

Description

TECHNICAL FIELD

The present invention relates to a drive unit for a variable capacity compressor, and more particularly, to a drive unit for a variable capacity compressor, which has a simplified structure.

BACKGROUND ART

In general, a compressor applied to air conditioning systems sucks refrigerant gas having passed through an evaporator to compress the same to high temperature and high pressure, and then discharges the compressed refrigerant gas to a condenser. As this compressor, there are used various types of compressors such as a reciprocating compressor, a rotary compressor, a scroll compressor, and a swash plate compressor.

The swash plate compressor includes a disc-shaped swash plate that is obliquely installed to a drive shaft rotated by power transmitted from an engine to be rotated by the drive shaft. In addition, the principle of the swash plate compressor is to suck or compress and discharge refrigerant gas by rectilinearly reciprocating a plurality of pistons within cylinders along with the rotation of the swash plate. By way of example, a variable capacity-type swash plate compressor disclosed in Korean Patent Application Publication No. 2012-0100189 includes a swash plate, which is installed to a drive shaft and has an angle of inclination varied with the thermal load, in order to regulate the discharge rate of refrigerant in such a manner that the feed rates of pistons are changed while the angle of inclination of the swash plate is varied.

Typically, a drive unit for a conventional variable capacity-type swash plate compressor has a structure in which a hinge pin fixedly positioned to a hub slides relative to a rotor fixed to a rotary shaft to adjust an angle of inclination of a swash plate through a shaft bush sliding about the rotary shaft.

However, this hinge mechanism requires the process of press-fitting the rotor to the rotary shaft, thereby causing complexity of work processes and product structures. Hence, the drive unit is disadvantageous in terms of weight, process, or price competitiveness. In addition, the drive unit is disadvantageous in that the gap between components is relatively large due to the clearance of the high mechanism.

DISCLOSURE

Technical Problem

Accordingly, the present invention has been made in view of the above-mentioned problems, and an object thereof is to provide a drive unit for a variable capacity compressor, which has a simplified structure.

Technical Solution

In accordance with one aspect of the present invention, a drive unit for a variable capacity compressor includes a drive shaft (100), one end of which is connected to a pulley of an engine, so that a driving force is transmitted from the engine to the drive shaft (100), a support balance (300) coupled to a pulley-side end of the drive shaft (100) to support a thrust bearing, a swash plate (500) spaced apart from the support balance (300) and allowing a discharge rate and a pressure of refrigerant to be regulated according to an angle of inclination of the swash plate (500), a hinge part (700) configured to connect the support balance (300) to the swash plate (500) and transmit a rotational force of the drive shaft (100) to the swash plate (500), and a friction ring module configured to control the angle of inclination of the swash plate (500) under low flow conditions by a frictional force generated between the drive shaft (100) and the friction ring module.

The friction ring module may include a polygonal pipe-shaped ring body (1000) fitted to the drive shaft (100) in its longitudinal direction, and a support spring (1100) fitted onto the ring body (1000).

Alternatively, the friction ring module may include a cylindrical ring body (1000a) fitted to the drive shaft (100) in its longitudinal direction, and a support spring (1100) fitted onto the ring body (1000a).

The ring body (1000, 1000a) may have an inner diameter smaller than an outer diameter of the drive shaft (100).

The ring body (1000, 1000a) may have an opening (1002, 1002a) formed in its longitudinal direction.

The drive unit may further include a circular or semicircular retainer (1300) disposed at one side of the drive shaft (100) facing the connected pulley to restrict movement of the friction ring module.

The ring body (1000, 1000a) may include a plurality of hooks (1004, 1004a) extending outward from one end thereof facing the swash plate (500) and bent toward the retainer (1300).

The support spring (1100) may be inserted between the hooks (1004, 1004a) and the ring body (1000, 1000a).

The support spring (1100) may have an inner diameter greater than an outer diameter of the ring body (1000, 1000a).

A distance between the ring body (1000, 1000a) and each of the hooks (1004, 1004a) may be larger than a thickness of the support spring (1100).

The ring body (1000, 1000a) may move along the drive shaft (100) when the angle of inclination of the swash plate (500) is changed, and be stopped by coming into contact with the retainer (1300) when the swash plate (500) is inclined at a minimum angle.

The ring body (1000a) may have a plurality of friction protrusions (1006a) protruding from its inner peripheral surface to the drive shaft (100).

In accordance with another aspect of the present invention, in a variable capacity compressor includes a drive shaft (100) rotatably supported in a housing and a swash plate (500) allowing a discharge rate of refrigerant to be variably controlled according to an angle of inclination of the swash plate (500) while a driving force transmitted to the drive shaft (100) is transmitted to the swash plate (500), the variable capacity compressor includes a friction member (1000, 1000a) coupled to the drive shaft (100) to be axially movable, positioned between the swash plate (500) and a support spring (1100) for applying a force in a direction of increasing the angle of inclination of the swash plate in an initial stage of operation, and configured to have a centrifugal force, wherein the friction member (1000, 1000a) restricts a rapid change in the angle of inclination of the swash plate (500) under low flow conditions by a frictional force generated between the friction member (1000, 1000a) and the drive shaft (100).

The friction member (1000, 1000a) may be modularized with the support spring (1100) to be axially coupled to the drive shaft (100).

Advantageous Effects

A drive unit for a variable capacity compressor according to exemplary embodiments of the present invention has an effect of maintaining controllability and also preventing a hunting problem caused under low flow conditions since it includes a friction ring module.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an assembled perspective view illustrating a drive unit for a variable capacity compressor at a maximum angle of inclination according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view illustrating the drive unit for a variable capacity compressor according to FIG. 1.

FIG. 3 is a perspective view illustrating a friction ring of the drive unit for a variable capacity compressor according to FIG. 1.

FIG. 4 is a perspective view illustrating a friction ring of a drive unit for a variable capacity compressor according to another embodiment of the present invention.

FIG. 5 is a top view illustrating a coupled state of the friction ring according to FIG. 4.

BEST MODE FOR INVENTION

Hereinafter, a drive unit for a variable capacity compressor according to exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is an assembled perspective view illustrating a drive unit for a variable capacity compressor at a maximum angle of inclination according to an embodiment of the present invention. FIG. 2 is an exploded perspective view illustrating the drive unit for a variable capacity compressor according to FIG. 1. FIG. 3 is a perspective view illustrating a friction ring of the drive unit for a variable capacity compressor according to FIG. 1.

As illustrated in FIGS. 1 and 2, the drive unit for a variable capacity compressor, which is designated by reference numeral 10, according to the embodiment of the present invention is inserted into a compressor consisting of a cylinder block and front and rear housings. The drive unit 10 includes a pulley (not shown) that is powered by an engine, a drive shaft 100 that is coupled to the pulley to be rotated by the pulley, and a support balance 300 and a swash plate 500 that are coupled to the drive shaft. The support balance 300 and the swash plate 500 are interconnected by a hinge part 700. A coil spring 910 and a bush 900 are coupled between the swash plate 500 and the drive shaft 100 to help initially operate the swash plate 500. The drive unit 10 includes a friction ring module that is formed at the opposite end of the pulley connection portion of the drive shaft 100, thereby maintaining controllability and also preventing hunting under low flow conditions.

One end of the drive shaft 100 is connected to the pulley to be rotatably supported by the front housing, and the other end thereof is rotatably supported by the rear housing. The drive shaft 100 has a hinge connection portion 110 that is in contact with the support balance 300.

The hinge connection portion 110 serves to prevent the support balance 300 from moving to the swash plate 500 while connecting the hinge part 700 to the drive shaft 100. To this end, the hinge connection portion 110 has a through-hole that is formed through the drive shaft 100 in the direction leading both ends of a counter weight 330 of the support balance 300 in FIG. 1 (the direction is defined on the basis of the support balance since the support balance is fixedly coupled to the drive shaft so as not to rotate for itself). The through-bole formed in the hinge connection portion 110 may affect the stiffness of the drive shaft 100. Therefore, it is preferable to prevent a reduction in stiffness of the drive shaft 100 by reinforcing the thickness of the drive shaft 100 in the vicinity of the through-hole. Accordingly, the hinge connection portion 110 is formed to protrude outward from the outer peripheral surface of the drive shaft 100.

The support balance 300 is coupled to the pulley-side end of the drive shaft 100, and the swash plate 500 is fitted to the drive shaft 100 in the state in which the swash plate 500 is spaced apart from the support balance 300 by a predetermined distance.

The support balance 300 is substituted for a conventional rotor formed integrally with lug plates, and serves to support a thrust bearing (not shown). The conventional rotor is disposed opposite to the swash plate in order to transmit rotational force to the swash plate and balance the drive unit (static balance function) since yawing is generated due to imbalance of weight when a mass is provided on the drive shaft 100. Although the conventional rotor formed integrally with lug plates is performed for the above functions, it is difficult to reduce the size of the drive unit due to the large size and weight of the rotor and the complicated hinge structure. In addition, the drive shaft 100 or the peripheral parts thereof may be deformed in the process of press-fitting the rotor to the drive shaft 100. Accordingly, the present invention is intended to propose the support balance 300 as a substitute for the rotor.

The support balance 300 includes a disc-shaped bearing support 310, a stepped portion 312 that protrudes toward the connected pulley and has a smaller diameter than the bearing support 310, and a ring-shaped counter weight 330 that is provided on one side of the outer peripheral surface of the bearing support 310 and has a greater radius than the bearing support 310.

The stepped portion 312 is formed integrally with the bearing support 310, and each of the bearing support 310 and the stepped portion 312 has a hollow formed at the center thereof for insertion of the drive shaft 100.

The counter weight 330 is preferably disposed at the lower side of the bearing support 310 in the arrangement of the drive unit illustrated in FIGS. 1 and 2. The support balance 300 has an eccentric load by the one-sided counter weight 330 thereto. The counter weight 330 serves to prevent an eccentricity of weight due to the structure of the hinge part 700 for adjusting the angle of the swash plate, and is thus disposed opposite to the weighted portion of the swash plate 500 and the hinge part 700.

Unlike the conventional rotor coupled by press-fit, the support balance 300 has an eccentric structure at the hollow thereof into which the drive shaft 100 is inserted. Thus, the support balance 300 is maintained in the coupled state without rotating on the drive shaft 100.

The swash plate 500 is connected to a piston (not shown) inserted into a cylinder bore formed in the cylinder block. The piston reciprocates in the cylinder bore along with the rotation of the swash plate 500 to thereby suck refrigerant or compress the refrigerant in the cylinder bore. The discharge rate and pressure of the refrigerant is regulated by adjusting the angle of inclination of the swash plate 500.

The swash plate 500 has a swash plate arm 510 and a hub 530 that protrude from the flat surface thereof facing the support balance 300. The swash plate arm 510 is relatively disposed at the upper side of the swash plate 500 whereas the hub 530 is relatively disposed at the lower side of the swash plate 500 in the state in which the hub 530 is spaced apart from the swash plate arm 510, in FIGS. 1 and 2.

The swash plate arm 510 consists of a pair of swash plate arms that face each other and are made of a sheet of metal, and the swash plate arms 510 have respective through-holes formed therein for insertion of a second hinge pin 770 to be described later. The hinge part 700 is inserted between the swash plate arms 510 to be rotatably coupled to the swash plate arms 510 by the second hinge pin 770.

The hub 530 has a substantially semi-cylindrical shape, and protrudes further than the swash plate arms 510 toward the support balance 300. The hub 530 serves to restrict the movement of the swash plate 500 such that the swash plate 500 is not inclined above a predetermined angle when the angle of inclination of the swash plate 500 is adjusted. To this end, the hub 530 preferably protrudes enough to come into contact with the support balance 300 when the swash plate 500 is inclined at a maximum angle.

The support balance 300 is connected to the swash plate 500 by the hinge part 700.

The hinge part 700 includes a pair of first hinge arms 710 disposed at both sides of the hinge connection portion 110 of the drive shaft 100, a second hinge arm 730 protruding toward the swash plate arms 510, a first hinge pin 750 coupled to the first hinge arms 710, and a second hinge pin 770 coupled to the second hinge arm 730.

The first hinge arms 710 are connected to the second hinge arm 730. The first hinge arms 710 face each other and are made of a sheet of metal. The first hinge arms 710 grasp the hinge connection portion 110 at both sides thereof and have respective through-holes formed therein for insertion of the first hinge pin 750, in FIG. 3. The first hinge pin 750 is coupled to the first hinge arms 710 by passing through the through-hole of the hinge connection portion 110 through one of the first hinge arms 710 and then passing through the other of the first hinge arms 710. The first hinge arms 710 are rotatably coupled to the hinge connection portion 110 by the first hinge pin 750. If the hinge connection portion 110 has a curved outer peripheral surface according to the shape of the outer peripheral surface of the drive shaft 100, the hinge connection portion 110 does not come into surface contact with the first hinge arms 710 but a gap is formed therebetween. Thus, the contact surface of the hinge connection portion 110 coming into contact with the first hinge arms 710 is preferably flat rather than curved such that the first hinge arms 710 are able to stably grasp the hinge connection portion 110.

The second hinge arm 730 has a thickness corresponding to the distance between the pair of swash plate arms 510, and has a through-hole formed therein for insertion of the second hinge pin 770. The second hinge pin 770 is inserted into one of the swash plate arms 510, passes through the second hinge arm 730, and is then inserted into the other facing swash plate arm 510. The swash plate arms 510 are rotatably coupled to the second hinge arm 730 by the second hinge pin 770.

As illustrated in FIG. 2, the bush 900 has a cylindrical shape and is inserted between the swash plate 500 and the drive shaft 100. The coil spring 910 is inserted between the bush 900 and the drive shaft 100. The bush 900 is elastically supported by the coil spring 910 and slides along the drive shaft 100. The bush 900 slides together with the swash plate 500 when the angle of inclination of the swash plate 500 is changed, with the consequence that the swash plate 500 is smoothly movable along the drive shaft 100.

Meanwhile, the friction ring module is provided to prevent a hunting phenomenon in which noise occurs when the angle of the swash plate is not maintained small due to too low friction under low flow conditions.

As illustrated in FIGS. 2 and 3, the friction ring module includes a ring body 1000 and a support spring 1100. A retainer 1300 is fitted to the opposite end of the pulley connection portion of the drive shaft 100 to restrict the movement of the friction ring module. The retainer 1300 has a circular or semicircular ring shape, and serves as a stopper.

The ring body 1000 has a polygonal pipe shape. A portion of the ring body 1000 is cut to form an opening 1002, and the ring body 1000 is fitted to the drive shaft 100 in the longitudinal direction thereof. Since the ring body 1000 is not cylindrical, the ring body 1000 is coupled to the drive shaft 100 with a gap therebetween in some sections without entirely surrounding the outer peripheral surface of the drive shaft 100. The opening 1002 is formed in the longitudinal direction of the drive shaft 100. Preferably, the ring body 1000 has an inner diameter smaller than the outer diameter of the drive shaft 100 in the state in which the opening 1002 is not formed in the ring body 1000. This is to generate a force in the central direction of the drive shaft 100 and thus generate a frictional force between the ring body 1000 and the drive shaft 100. There is no problem in the assembly of the ring body 1000 because the ring body 1000 has the opening 1002 even though the inner diameter of the ring body 1000 is smaller than the outer diameter of the drive shaft 100. The ring body 1000 has a plurality of hooks 1004 formed at one end thereof facing the swash plate 500 so that the support spring 1100 is coupled to the hooks 1004.

The hooks 1004 extend outward from one end of the ring body 1000 facing the swash plate 500 and are bent toward the retainer 1300. Preferably, the distance between each of the hooks 1004 and the outer peripheral surface of the ring body 1000 is larger than the thickness of the support spring 1100 so as not to interfere with the operation of the support spring 1100. The support spring 1100 is inserted between the hooks 1004 and the ring body 1000.

One end of the support spring 1100 is inserted between the hooks 1004 and the ring body 1000, and the other end thereof extends toward the retainer 1300. The support spring 1100 has an inner diameter slightly greater than the outer diameter of the ring body 1000.

The reason that the hooks 1004 are formed in the ring body 1000 despite the greater inner diameter of the support spring 1100 than the outer diameter of the ring body 1000 is to smoothly assemble the support spring 1100. That is, the hooks 1004 serve to temporarily fix the support spring 1100 in the assembly thereof to prevent the support spring 1100 from moving to the swash plate 500. However, the hooks 1004 does not interfere with the movement of the support spring 1100 to the retainer 1300.

As illustrated in FIGS. 4 and 5, a friction ring module of a drive unit according to another embodiment of the present invention includes a cylindrical ring body 1000a having an opening 1002a formed at one side thereof. The ring body 1000a has a plurality of hooks 1004a formed on the outer peripheral surface thereof, and may further have a plurality of friction protrusions 1006a protruding from the inner peripheral surface thereof to the drive shaft 100 (the same components as those of the previous embodiment will not be described in detail).

The friction protrusions 1006a serve to increase a frictional force between the drive shaft 100 and the ring body 1000a, and to increase a force generated in the central direction of the drive shaft 100, as illustrated in FIG. 5.

The shape of the ring body 1000a is not restricted. However, in the case where the ring body 1000a is configured to have a cylindrical shape and support the drive shaft 100 at three points by the friction protrusions 1006a and uses a multiple press as in the present embodiment, it is possible to enhance productivity.

If the frictional force is too high, there is a problem in that pressure does not change at all due to fixation of the friction ring module to the drive shaft 100. On the other hand, if the frictional force is too low, there is a problem in that noise occurs (hunting) since it is difficult to keep the angle of the swash plate small under low load conditions.

In the present invention, the ring body 1000a has an inner diameter smaller than the outer diameter of the drive shaft 100 or has the friction protrusions 1006a to properly maintain the frictional force. Therefore, the drive unit has an effect of maintaining controllability and also preventing hunting under low flow conditions.

In the above-mentioned embodiments, the ring body 1000 or 1000a moves between the bush 900 and the retainer 1300 that are inserted between the swash plate 500 and the drive shaft 100, and the movement of the ring body is stopped while the ring body is pushed by the bush 900 at the minimum angle of the swash plate 500 to come into contact with the retainer 1300. Accordingly, the length of the ring body 1000 or 1000a in the longitudinal direction of the drive shaft 100 is varied depending on the position of the retainer 1300 when the swash plate 500 is inclined at a minimum angle.

Meanwhile, the ring body 1000 may be coupled to the drive shaft 100 to be axially movable, may be positioned between the swash plate 500 and the support spring 1100 for applying a force in the direction of increasing the angle of inclination of the swash plate in the initial stage of operation, and may be configured to have a centrifugal force. Thus, since the ring body 1000 serves to restrict a rapid change in the angle of inclination of the swash plate 500 under low flow conditions by the frictional force generated between the ring body 1000 and the drive shaft 100, the ring body 1000 may be defined as a friction member. In addition, the ring body 1000 may be modularized with the support spring 1100 to be axially coupled to the drive shaft 100.

Since the drive unit includes the friction ring module having the above-mentioned structure, it is possible to maintain controllability and prevent a hunting problem caused under low flow conditions.

INDUSTRIAL APPLICABILITY

The present invention can be applied to a drive unit for a variable capacity compressor, which has a simplified structure.

Claims

1.-14. (canceled)

15. A drive unit for a variable capacity compressor, comprising:

a drive shaft, one end of which is connected to a pulley of an engine, so that a driving force is transmitted from the engine to the drive shaft;

a support balance coupled to a pulley-side end of the drive shaft to support a thrust bearing;

a swash plate spaced apart from the support balance and allowing a discharge rate and a pressure of refrigerant to be regulated according to an angle of inclination of the swash plate;

a hinge part configured to connect the support balance to the swash plate and transmit a rotational force of the drive shaft to the swash plate; and

a friction ring module configured to control the angle of inclination of the swash plate under low flow conditions by a frictional force generated between the drive shaft and the friction ring module.

16. The drive unit according to claim 15, wherein the friction ring module comprises a ring body fitted to the drive shaft in its longitudinal direction, and a support spring fitted onto the ring body.

17. The drive unit according to claim 16, wherein the ring body is polygonal pipe shape or cylindrical shape.

18. The drive unit according to claim 16, wherein the ring body has an inner diameter smaller than an outer diameter of the drive shaft.

19. The drive unit according to claim 16, wherein the ring body has an opening formed in its longitudinal direction.

20. The drive unit according to claim 16, further comprising a circular or semicircular retainer disposed at one side of the drive shaft facing the connected pulley to restrict movement of the friction ring module.

21. The drive unit according to claim 20, wherein the ring body comprises a plurality of hooks extending outward from one end thereof facing the swash plate and bent toward the retainer.

22. The drive unit according to claim 21, wherein the support spring is inserted between the hooks and the ring body.

23. The drive unit according to claim 22, wherein a distance between the ring body and each of the hooks is larger than a thickness of the support spring

24. The drive unit according to claim 16, wherein the support spring has an inner diameter greater than an outer diameter of the ring body.

25. The drive unit according to claim 20, wherein the ring body moves along the drive shaft when the angle of inclination of the swash plate is changed, and is stopped by coming into contact with the retainer when the swash plate is inclined at a minimum angle.

26. The drive unit according to claim 16, wherein the ring body has a plurality of friction protrusions protruding from its inner peripheral surface to the drive shaft.

27. A variable capacity compressor, which comprises a drive shaft rotatably supported in a housing and a swash plate allowing a discharge rate of refrigerant to be variably controlled according to an angle of inclination of the swash plate while a driving force transmitted to the drive shaft is transmitted to the swash plate, the variable capacity compressor comprising:

a friction member coupled to the drive shaft to be axially movable, positioned between the swash plate and a support spring for applying a force in a direction of increasing the angle of inclination of the swash plate in an initial stage of operation, and configured to have a centrifugal force,

wherein the friction member restricts a rapid change in the angle of inclination of the swash plate under low flow conditions by a frictional force generated between the friction member and the drive shaft

28. The variable capacity compressor according to claim 27, wherein the friction member is modularized with the support spring to be axially coupled to the drive shaft.