KR920007053B1 - Capacity variable type compressor - Google Patents

Abstract

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Description

Capacity variable compressor

1 is a cross-sectional view of a variable displacement compressor according to the present invention, showing when the inclination angle of the inclined plate is the maximum.

2 is a cross-sectional view of a variable displacement compressor showing when the inclination angle of the inclined plate is minimum.

Figure 3a is a cross-sectional view of a conventional connection between the piston and the inclined plate.

Figure 3b is a cross-sectional view of a conventional connecting device illustrating a state in which a gap is generated between the inclined plate and the slip shoe due to the change of the inclined angle of the inclined plate.

4 is a cross-sectional view of the connecting device between the piston and the inclined plate according to the present invention.

* Explanation of symbols for main parts of the drawings

1: Cylinder casing 1a: Crankcase

2: Cylinder block 3: Front housing

4: driving shaft 5: radial bearing

8: rotor (rotor) 8a: rotor protrusion

8b: long hole (in the rotor protrusion)

9: spherical surface bush

10: inclined plate 10a: inclined plate protrusion

10b: hole 11 for inclined plate protrusion

12 spring 13: thrust trajectory

14, 16: thrust needle bearing 15: radial needle bearing

17: leaf spring 18: adjustment screw

19: sliding shoe 20: piston rod

21: piston 22: suction hole

23: discharge hole 24: valve plate

25, 29: gasket 26: cylinder head

26a: bulkhead 27: suction chamber

27a: suction port 28: discharge chamber

28a: outlet 30, 30a, 30b, 31a, 33a: hole

31: connecting device 31b: valve seat

32: O-ring 33: stand

34: bellows 34a: needle

40: compressor

The present invention relates to an inclined plate compressor, in particular, a variable displacement compressor for use in a refrigerator.

Compressors for compressing fluid by changing the inclination angle of the inclined plate by the reciprocating motion of the piston have conventionally existed, and there has also been a compressor for converting the amount of compression by changing the stroke length of the piston connected to the inclined plate by changing the inclination angle of the inclined plate.

In the variable displacement compressor as mentioned above, the swash plate comprises a cam rotor and a swash plate. The angle of the cam rotor connected to the rotating shaft can be changed. The swash plate moves together in accordance with the movement of the cam rotor, and its inclination angle changes in accordance with the change of the angle of the cam rotor. The piston is connected to the swash plate through the connecting rod, and its stroke length is changed according to the change of the inclination angle of the swash plate. In this way the compression capacity of the compressor is varied.

However, in such a conventional compressor, the configuration of the bearing configuration for changing the angle of the cam rotor, the swash plate and the support for the cam rotor is very complicated. In addition, a rotation preventing device is necessary to prevent rotation of the swash plate.

In addition, the rotation prevention device cannot use the structure of the bevel gear as used in the fixed capacity compressor because the rotation prevention device must be operated correctly in the variable displacement compressor when the inclination angle of the inclination plate is changed. Accordingly, the rotation preventing device in the variable displacement compressor includes a sliding rod protruding radially from the outer circumference of the swash plate and a guide groove formed axially in the crankcase. Rotation of the swash plate is prevented by sliding of the sliding rod in the guide groove. However, there is a problem in durability because of the rubber part in the anti-rotation device. In addition, since the sliding friction changes according to the movement range of the swash plate, the angular velocity transmitted to the swash plate is not uniform during the change of the inclination angle, and vibration is generated.

It is an object of the present invention to provide a variable displacement compressor having a simple structure and a highly reliable anti-rotation device.

The present invention relates to a variable displacement compressor comprising a housing including a crank chamber, a drive shaft rotatably supported in the housing, and an inclined plate connected to the drive shaft. A plurality of pistons are reciprocated by the rotation of the inclined plate. The connecting device connects the piston to the swash plate, which makes it possible to slide along the circumferential surface of the swash plate. Since the hinge connecting portion connects the inclined plate to the drive shaft, the inclination angle of the inclined plate is varied within a predetermined range. The control means regulates the pressure in the crankcase. The connecting device includes a pair of sliding shoes and a support of a piston for supporting the sliding shoes.

Each shoe has a first surface in contact with the major surface of the inclined plate and a spherical surface opposite thereto. This spherical surface forms an outer surface with a cavity center.

Other objects, features and other forms of the present invention will be understood in accordance with the following description in the preferred embodiments of the present invention with reference to the attached drawings.

1, an embodiment of a variable displacement compressor according to the present invention is shown. The compressor 40 includes a front housing 3, a valve plate 24, a cylinder head 26 attached to an end surface of the front housing 3 and an end surface of the valve plate 24. The cylinder block 2 is formed at the end of the cylinder casing 1, and forms the cylinder bore 2a. In the center of the front housing 3, a hole 3a is formed so that the drive shaft 4 penetrates. A radial bearing 5 is arranged into the hole 3a for rotatably supporting the drive shaft 4.

The sleeve 3b extends from the outer end of the hole 3a of the front housing 3 to surround the drive shaft 4. The sealing device 7 is arranged in the sealing chamber 6 formed between the outer surface of the drive shaft 4 and the inner wall of the sleeve 3b. A crank chamber 1a is formed between the inner wall of the front housing 3 and the end surface of the cylinder block 2. A rotor (rotor) 8 is disposed at one end of the drive shaft 4 in the crank chamber 1a.

At the end of the rotor 8, an ear-shaped protrusion 8a is formed. An elongated hole 8b is formed in this ear-shaped rotor projection 8a.

A spherical surface bush 9 is arranged on the drive shaft 4 at some distance from the rotor 8 and slides on this drive shaft 4. It is arrange | positioned so that it may slide on the spherical bush 9 of the disk-shaped inclination board 10. As shown in FIG. On one end surface of the inclined plate, an ear-shaped protrusion 10a is formed toward the protrusion 8a of the rotor 8, and the protrusion 10 has a hole aligned with the elongated hole 8b of the rotor 8 ( 10b) is formed. The pin 11 is inserted through both the elongated hole 8b of the rotor 8 and the protrusion hole 10b of the inclined plate 10, and the pin 11 is inserted into the elongated hole 8b of the rotor 8. Can slide. As such, the hinge connection portion connecting the inclined plate 10 to the drive shaft 4 has an elongated hole 8b provided in the protrusion 8a of the rotor 8, a protruding hole 10b of the inclined plate 10, and It consists of a pin (11). A spring 12 is provided on the outer side of the drive shaft 4 so as to contact both the rotor 8 and the spherical bush 9 on both sides. A pair of thrust races 13 are arranged on the inner wall surface of the front housing 3 and on the opposite surface of the rotor 8. A thrust needle bearing 14 is arranged between the thrust trajectories 13.

The other end of the drive shaft 4 is rotatably supported by the radial needle bearing 15 in the cylinder block 2. Moreover, the other end of the drive shaft 4 is rotatably supported opposite the leaf spring 17 and the thrust needle bearing 16 by means of an adjusting screw 18.

Sliding shue 19 is provided on both sides of the inclined plate 10, and the major surface of the inclined plate 10 is arrange | positioned between the planes of each sliding shoe 19, respectively. The sliding shoe 19 forms the spherical curved surface on the opposite side to the surface which contact | connects the inclined board. The main surface of the inclined plate 10 in contact with the sliding shoe 19 slides along the plane of the shoe 19. As shown in FIG. 1, the outer curved surfaces of the pair of sliding shoes 19 are arranged to form a sphere of radius R generally. The center of the sphere formed by the outer curved surface of the sliding shoe 19 is located along the plane dividing the inclined plate 10, that is, the center of the thickness of the inclined plate 10. A sliding shoe 19 is supported between the piston rod 20 and the inclined plate 10 formed so that one end thereof is divided into two. The piston 21 is disposed at the other end of the piston rod 20 or integrally formed with the piston rod, and is slidably housed in the cylinder border 2a. Many such piston rods and several phase slip shoes are installed in the compressor.

A suction hole 22 for introducing the fluid and a discharge hole 23 for discharging the fluid are formed through the valve plate 24. One side of the valve plate 24 is connected to the cylinder block 2 via the gasket 25, and the other side of the valve plate 24 is connected to the cylinder head 26 via the gasket 29. The partition 26a of the cylinder head 26 divides the cylinder head 26 into the suction chamber 27 and the discharge chamber 28. The cylinder casing 1 is sealed by attaching the valve plate 24 and the cylinder head 26 to the upper portion of the cylinder block 2. The suction port 27a is provided inside the suction chamber 27, and the discharge port 28a is provided outside the discharge chamber 28.

In order to connect the crank chamber 1a and the suction chamber 27, a hole 30 is formed through the cylinder block 2. The hole 30 consists of the hole 30a which penetrates the valve plate 24 and the gaskets 25 and 29, and the hole 30b in which the bellows 34 is contained.

A connecting device 31 having a hole 31a and a valve seat 31b is disposed on the surface facing the crank chamber 1a in the hole 30b. The O-ring 32 is sandwiched between the connecting device 31 and the cylinder block 2 to prevent leakage of the fluid gas. A pedestal 33 having holes 33a at both upper ends thereof is fixed in the hole 30b. A bellows 34 having a needle 34a at its upper end is arranged on the pedestal 33 and filled with gas under constant pressure. When the upper end of the needle 34a is fitted into the hole 31a, the hole 31a is sealed by the needle 34a and the valve seat 31b of the connecting device 31.

1 and 2, the operation of a compressor as described above for use in a refrigeration circuit system is shown.

When the rotational force from the drive source rotates the drive shaft 4, this rotational force is transmitted to the inclined plate 10 through the rotor 8 and the hinge connection portion, and the inclined plate 10 is rotated. However, since the main surface of the inclined plate 10 is slid between the opposing planes of the pair of slip shoes 19 during the rotation of the inclined plate 10, the rotational force is applied to the piston rod 20 connected to the slip shoes 19. Not delivered. That is, the piston 21 does not move in the up and down direction of the drawing. Therefore, the rotational force of the inclined plate 10 is converted into the reciprocating motion of the piston 21 in the left and right directions of the drawing. Due to the reciprocating motion of the piston 21, the fluid sucked from the suction hole 22 to the cylinder bore 2a is compressed and discharged to the discharge chamber 28 through the discharge hole 23.

Hereinafter, a method of changing the compression capacity of the compressor will be described. When the air regulating load is higher than the set temperature of the air conditioner, and when the freezing capacity is insufficient, the suction pressure of the refrigerant is increased and thus the pressure in the suction chamber is also raised. Therefore, the pressure in the hole 30b connected to the suction chamber 27 also rises.

The gas in the bellows 34 disposed in the hole 30b is sealed so that the pressure of the gas is slightly higher than the suction pressure corresponding to the set temperature in the refrigeration system.

Therefore, when the air control load is higher than the temperature of the air conditioner, the bellows 34 is leveled to the right as shown in FIG. 1, and the needle 34a is separated from the valve seat 31b so that the hole 31a is opened. ). Therefore, the suction chamber 27 is connected to the crank chamber 1a. Since the gas leaked into the crank chamber 1a by the operation of the compressor is returned to the suction chamber 27, the pressure in the crank chamber 1a is almost equal to the pressure in the suction chamber 27.

In this state, the reaction force of the gas compression acts on the inclined plate 10 in the compression cycle by a plurality of pistons arranged at the same angle on the inclined plate 10, and thus acts on the hinge connection portion described above. The moment M ₁ is generated by the reaction force acting on the piston 21, and the moment M ₃ is generated by the pressure difference between the crank chamber 1a and the suction chamber 27. Therefore, when the hole 31a is opened and there is no pressure difference between the crank chamber 1a and the suction chamber 27, only the moment M ₂ is opposed to the moment M ₁ .

Thus, if the restoring force of the coil spring 12 is set such that the moment M ₂ is greater than the moment M ₁ , it moves toward the rotor 8 of the inclined plate 10 and the pin 11 of the hinge connection portion. It is rotated about the pin 11 is dried to the upper end of the elongated hole (8b) of the rotor (8). Therefore, the inclination angle of the inclined plate 10 is maximum with respect to the vertical plane.

This provides the maximum stroke of the piston 21 in the cylinder 2a corresponding to the normal refrigerant capacity of the compressor.

When the air conditioning load is low and the compressor is running at high speed, the compression capacity of the compressor becomes excessive. Therefore, the pressure in the suction chamber 27 is reduced, and the bellows 34 is moved to the left to close the hole 31a by the needles 34a. This state is shown in FIG. In this case, the pressure in the crank chamber 1a gradually increases, and blow-by gas leaking from the cylinder chamber into the crank chamber through the gap between the piston and the cylinder during the compression stroke is introduced into the crank chamber. As it is included, a small pressure difference occurs. While the pressure in the crank chamber 1a increases, the moment M ₃ is generated, and its magnitude increases in response to the increase in the pressure in the crank chamber 1a.

Since this moment M ₃ is opposed to the moment M ₁ , at some point the total size of the moments M ₂ and M ₃ exceeds the moment M ₁ . In this case, since the moment in the counterclockwise direction acts on the inclined plate 10 about the pin 11 of the hinge connection portion, the inclination angle of the inclined plate 10 with respect to the vertical plane is reduced. The reduction of the inclination angle continues until the pin 11 contacts the lower end of the elongated hole 8b of the rotor 8.

As the angle of inclination is reduced, the stroke of the piston in the cylinder is reduced, and the capacity of the compressor is gradually reduced. A complete stop of the piston movement is undesirable because the ejection of refrigerant gas and lubricant is stopped, so some movement of the piston must be maintained to maintain continuous lubrication of the compressor.

The length of the elongated hole 8b of the rotor 8 at the hinge connection is determined so that the minimum compression amount is about 20 to 30 percent of the maximum compression amount.

Referring to FIG. 3A, there is shown a connection device of a piston and an inclined plate conventionally used. A hemispherical sliding shoe 19 having a radius B is arranged on both sides of the inclined plate 10 having a thickness t. The distance A between the spheres of the pair of sliding shoes 19 is as follows. It is represented by the formula (1).

Α is the angle of the vertical axis with respect to the central axis of the inclined plate 10.

As mentioned above, since the inclination angle of the inclined plate 10 changes, the spacing A between the spherical surfaces of the hemispheres shown in formula (1) changes according to the inclination angle of the inclined plate 10. Since the spacing A between the spherical surfaces changes according to the inclination angle of the inclined plate 10, and on the other hand, the spacing C between the supporting portions 35 is fixed, the spacing A between the spherical surfaces is shown in FIG. 3A. Although shown to be the same distance as the spacing (C) between the support portion 35 of the piston rod 20 as shown, as shown in Figure 3b, there is a gap between the sliding shoe 19 and the inclined plate 10 And smooth operation of the piston 21 is hindered.

On the other hand, as shown in FIG. 4, the sliding shoe 19 according to the present invention forms a spherical surface on the inclined plate 10 opposite to the joining plane, respectively. The pair of shoes 19 has a radius with a common center that the outer sphere is centered at a point on the center plane D of the inclined plate 10 (the surface of which is divided equally in half by the outer major surface of the inclined plate). It is arrange | positioned outside the main surface of the inclination board 10 so that the spherical surface of R) may be formed. The spacing A between the spheres is always the same without being constrained by the inclination angle of the inclined plate 10. Therefore, no gap is generated between the sliding shoe 19 and the inclined plate 10, and the piston 21 can always move smoothly.

Although the present invention has been described in detail in accordance with the preferred embodiment, this is not limited to the present invention only, but is only an embodiment. It will be readily understood by those skilled in the art that other changes and modifications can be readily made within the scope of the present invention.

Claims (3)

A housing 1 including a crank chamber 1a, a drive shaft 4 rotatably supported within the housing, an inclined plate 10 connected to the drive shaft, and reciprocating by rotation of the inclined plate. A plurality of pistons 21, a connecting device for connecting the pistons to the inclined plate so as to slide along the circumferential surface of the inclined plate, and the inclined plate to the drive shaft so that the inclination angle of the inclined plate is changed within a predetermined range. A variable capacity compressor comprising a hinge connecting portion (8b, 10b, 11) for connecting and a control means (34) for adjusting the pressure in the crankcase, wherein the connecting device comprises a pair of sliding shoes (19), and the sliding shoes. It consists of a support surface of the piston 21 for supporting the, the pair of sliding shoes 19 has a first surface and the opposite surface in contact with the main surface of the inclined plate 10, respectively Was, the capacity modulation compressor, which forms the outer surface of the spherical radius (R) that has a hollow center Wu the opposite side of the pair of the sliding shoe, respectively. A variable displacement compressor according to claim 1, wherein said control means (34) are bellows. The variable displacement compressor according to claim 1, wherein the cavity center of the spherical outer surface of the sliding shoe (18) lies on a center line (D) that bisects the thickness of the inclined plate (10).

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