Variable capacity swash plate type compressor

The present invention relates to a variable capacity swash plate type compressor, and more particularly, to a variable capacity swash plate type compressor, which has an elastic member mounted on a driving shaft located between a rotor and a swash plate for pushing a swash plate in a direction that an inclination angle is decreased to always contact and support a side of the swash plate to the rotor when the inclination angle of the swash plate is varied, thereby preventing a vibration of the swash plate and reducing noise during operation.

In general, a compressor constituting an air conditioning device of an automobile is a device for selectively receiving driving power from a power source by a restricting action of an electromagnetic clutch, compressing refrigerant gas by a straight reciprocating motion of pistons after absorbing the refrigerant gas from an evaporator, and discharging it toward a condenser. Such a compressor is classified into various kinds according to compression methods and structures, and out of the compressors of the various kinds, a variable capacity compressor, which can vary a compression volume, has been widely used.

Hereinafter, referring to FIGS. 1 and 2, a prior art variable capacity swash plate type compressor will be described as an example.

The variable capacity swash plate type compressor 1 includes: a cylinder block 10 having a plurality of cylinder bores 11 formed inside the cylinder block 10 axially along a concentric circle; a front housing 20 mounted in front of the cylinder block 10 and having a crank chamber 21 formed therein; a rear housing 30 mounted at the back of the cylinder block 10 and having a suction chamber 31 and a discharge chamber 32 formed therein; a plurality of pistons 40 reciprocatingly inserted into each of the cylinder bores 11 of the cylinder block 10 and having a bridge 41 at the rear end portion thereof; a driving shaft 50 having an end portion rotatably passing through the front housing 20 and the other end portion rotatably inserted and mounted into the center of the cylinder block 10; a rotor 60 combined to the driving shaft 50 inside the crank chamber 21 and rotating with the driving shaft 50; a swash plate 70 mounted on the circumference of the driving shaft 50 by slidably combining a sleeve 65 thereto, having an edge rotatably mounted to an insertion space of the piston bridge 41 by interposing a shoe 45 between the insertion space and the edge of the swash plate 70, and connected with the rotor 60 via hinge means 75 so as to adjust its inclination angle against the driving shaft 50 while rotating together with the rotor 60; and a valve unit 80 mounted between the cylinder block 10 and the rear housing 30 to inhale refrigerant from the suction chamber 31 into the cylinder bores 11 during a suction stroke and discharge compressed refrigerant from the cylinder bores 11 into the discharge chamber 32 during a compression stroke.

In addition, the inclination angle of the swash plate 70 against the driving shaft 50 can be adjusted according to a pressure change inside the crank chamber 21 by a control valve 90 mounted in the rear housing 30.

Furthermore, the compression coil spring 55 interposed on the driving shaft 50 between the rotor 60 and the swash plate 70 elastically supports the sleeve 65, to which the swash plate 70 is rotatably combined, against the rotor 60, so that the swash plate 70 can be returned to its original position.

Meanwhile, the hinge means 75 for connecting the rotor 60 and the swash plate 70 with each other includes a first hinge arm 61 formed on a side of the rotor 60 and having a slot 62, and a second hinge arm 71 formed on a side of the swash plate 70 and having a hinge pin 72 movably combined to the slot 62 of the first hinge arm 61.

As described above, in the variable capacity swash plate type compressor 1, a plurality of the pistons 40 arranged along the concentric circle of the cylinder block 10 perform the and backward reciprocating motion in order by the rotation of the swash plate 70.

Here, during the suction stroke of the pistons 40, a suction valve (not shown) of the valve unit 80 is opened by a drop of pressure inside the cylinder bores 11, whereby the cylinder bores 11 and the suction chamber 31 are fluidically communicated with each other and the refrigerant is induced from the suction chamber 31 into the cylinder bores 11.

Additionally, during the compression stroke of the pistons 40, a discharge valve (not shown) of the valve unit 80 is opened while the refrigerant is compressed by a rise of pressure inside the cylinder bores 11, whereby the cylinder bores 11 and the discharge chamber 32 are fluidically communicated with each other and the compressed refrigerant is discharged from the cylinder bores 11 into the discharge chamber 32.

In addition, the swash plate 70 adjusts its inclination angle in correspondence to a difference between pressure inside the crank chamber 21 and suction pressure inside the cylinder bores 11, whereby a discharge volume of the compressor 1 is varied.

Meanwhile, the slot 62 formed on the first hinge arm 61 of the rotor 60 guides the swash plate 70 when the inclination angle of the swash plate 70 is varied, and in this instance, keeps a fixed interval from the hinge pin 72 combined to the second hinge arm 71 of the swash plate 70 for a smooth operation.

Therefore, when the compressor 1 is in a condition of the largest angle, the inclination angle of the swash plate 70 is varied to the largest angle, and in this instance, the compression coil spring 55 is compressed.

During the process that the inclination angle the swash plate 70 is varied into the smallest angle or the largest angle, the hinge pin 72 guides an inclination motion of the swash plate 70 while moving along the slot 62.

However, while the compressor 1 is operated, particularly, operated on the variable condition, the swash plate 70 is vibrated by the interval (S) formed between the hinge pin 72 and the slot 62, and so, noise is generated.

The vibration of the swash plate 70 can reduce vibration and noise somewhat since the hinge pin 72 is at least in close contact with a side of the slot 62 in the condition of the smallest angle or the largest angle of the swash plate 70. However, since there is not structure for supporting the swash plate 70 in a section between the smallest angle and the largest angle, namely, since the hinge pin 72 is not in close contact with the inner circumference of the slot 62 but shakes, the swash plate 70 is vibrated and generates noise.

Meanwhile, the compression coil spring 55 for restoring the swash plate 70 to its initial position applies elasticity only to the sleeve 65 rotatably mounted on the swash plate 70, and so, the swash plate 70 is freely moved in directions that the inclination angle is increased and decreased, whereby the hinge pin 72 also shakes inside the slot 62.

Accordingly, it is an object of the present invention to provide a variable capacity swash plate type compressor, which has an elastic member mounted on a driving shaft between a rotor and a swash plate for pushing a swash plate in a direction that an inclination angle is decreased to always contact and support a side of the swash plate to the rotor when the inclination angle of the swash plate is varied, thereby preventing vibration of the swash plate and reducing noise during operation.