JP2002031058A - Reciprocating refrigerant compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reciprocating refrigerant compressor capable of enhancing the compressor efficiency. SOLUTION: The reciprocating refrigerant compressor is equipped with a cylinder block having a cylinder bore, a compression chamber formed in the cylinder bore for compression of the refrigerant, a rear head fixed to one end of the cylinder block and furnished with a discharge chamber into which refrigerant from the compression chamber flows in, a valve plate positioned between the cylinder block and rear head and furnished with a discharge port for putting the compression chamber in communication with the discharge chamber and a discharge valve 17 positioned between the rear head and valve plate for opening and closing of the compression chamber, and works with a refrigerant as working fluid which is carbon dioxide, wherein the discharge valve 17 is furnished with a guide projection 92 in approximately a hemispherical shape to guide the refrigerant to the discharge chamber when the discharge valve 17 is opened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a reciprocating refrigerant compressor, of a preferred reciprocating refrigerant compressor, especially CO ₂ as a refrigerant compressor of a vehicle air conditioner used as a refrigerant.

[0002]

2. Description of the Related Art A reciprocating refrigerant compressor has a cylinder block having a cylinder bore, a piston reciprocating linearly in the cylinder bore, a compression chamber formed in the cylinder bore, and a discharge from which refrigerant gas flows from the compression chamber. A cylinder head in which a chamber is formed, and a valve plate in which a discharge port for guiding refrigerant gas in the compression chamber to the discharge chamber is formed.
And a discharge valve for opening and closing the discharge port.

A valve plate, a discharge valve, and a cylinder head are fixed on one end surface of a cylinder block so as to be sequentially stacked.

[0004] When the piston moves from the bottom dead center position to the top dead center position, the refrigerant gas in the compression chamber is compressed. When a certain pressure difference occurs between the compression chamber and the discharge chamber, the discharge valve opens, and the refrigerant gas in the compression chamber flows out to the discharge chamber through the discharge port.

[0005]

The discharge capacity of a compressor using CO ₂ as a refrigerant is about ６ of that of a compressor using CFC as a refrigerant.

However, the pressure difference between the high pressure and the low pressure is significantly larger than that of a compressor using chlorofluorocarbon as a refrigerant (about 12).
MPa). Correspondingly, compressor efficiency was relatively low.

[0007] The present invention has been made in view of such circumstances, and an object thereof is to provide a reciprocating refrigerant compressor capable of improving compressor efficiency.

[0008]

According to a first aspect of the present invention, there is provided a reciprocating refrigerant compressor comprising: a cylinder block having a cylinder bore; and a refrigerant block formed in the cylinder bore to compress the refrigerant. A compression chamber, a cylinder head fixed to one end of the cylinder block and having a high-pressure chamber into which refrigerant from the compression chamber flows, and disposed between the cylinder block and the cylinder head; A valve plate provided with a discharge port communicating with the high-pressure chamber; and a discharge valve disposed between the cylinder head and the valve plate to open and close the compression chamber. In the reciprocating refrigerant compressor made of carbon, the discharge valve has a substantially hemispherical guide protrusion for guiding the refrigerant to the high-pressure chamber when the discharge valve is opened. Wherein the but has been formed.

As described above, since the discharge valve is formed with a substantially hemispherical guide protrusion for guiding the refrigerant to the high-pressure chamber when the discharge valve is opened, the guide function of the guide protrusion works.
The refrigerant in the compression chamber easily flows out to the high-pressure chamber.

According to a second aspect of the present invention, there is provided a reciprocating type refrigerant compressor according to the first aspect, wherein the discharge port is provided at a periphery of a high pressure chamber side opening of the discharge port when the discharge valve is closed. It is characterized in that a hole is formed in which the guide projection is in surface contact.

As described above, a hole (a dead volume) in the discharge port is formed at the periphery of the high pressure chamber side opening of the discharge port so that the guide projection is in surface contact when the discharge valve is closed. It is smaller than when no hole is formed in the periphery of the discharge port.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a longitudinal sectional view of a variable displacement swash plate type compressor according to an embodiment of the present invention, FIG. 2 (a) is a plan view of a valve plate, and FIG. 2 (b) is that of FIG. 3 (a) is a plan view of the discharge valve, FIG. 3 (b) is a partially enlarged cross-sectional view along the line III-III of FIG. 3 (a), and FIG. 4 is a discharge valve. 4A is a partially enlarged cross-sectional view, FIG. 4A is a diagram illustrating a state where the discharge valve is closed, and FIG. 4B is a diagram illustrating a case where the discharge valve is open.

The variable displacement type swash plate compressor is used as a component of a refrigeration cycle using CO ₂ (carbon dioxide) as a refrigerant. A rear head (cylinder head) 3 is disposed on one end surface of a cylinder block 1 of the compressor via a valve plate 2, and a front head 4 is disposed on the other end surface. The front head 4, the cylinder block 1, the valve plate 2, and the rear head 3 are integrally connected in the axial direction with a through bolt 31 and a nut 32.

The front head 4 has a crank chamber 8 for accommodating a thrust flange 40, a swash plate 10, and the like.

The thrust flange 40 is fixed to the shaft 5 and rotates integrally with the shaft 5.

The thrust flange 40 is rotatably supported on the inner peripheral surface 4a of the front head 4 via a thrust bearing 33. The swash plate 10 is mounted so as to be slidable with respect to the shaft 5 and tiltable with respect to an imaginary plane perpendicular to the shaft 5.

The swash plate 10 is connected to a thrust flange 40 via a link mechanism 41, and rotates integrally with the rotation of the thrust flange 40. Both sliding surfaces 10 of the swash plate 10
Hemispherical shoes 60, 61 are arranged on the swash plate 10 so as to sandwich the swash plate 10, and can relatively rotate on the sliding surfaces 10 a, 10 b of the swash plate 10 as the shaft 5 rotates.

The cylinder block 1 has a shaft 5
A plurality of cylinder bores 6 are formed at predetermined intervals along a circumference centered at. A piston 7 is slidably housed in the cylinder bore 6.

The piston 7 has a cylindrical portion 72 and a concave portion 7.
1, 70 and a bridge portion 7 connecting the concave portions 71, 70
And 3. The cylindrical portion 72 slides in the cylinder bore 6.

The concave portion 71 is formed at one end of the cylindrical portion 72, and holds the shoe 61 so as to roll.

The concave portion 70 is disposed to face the concave portion 71,
The shoe 60 is held so as to roll.

A suction chamber 13 and a discharge chamber (high-pressure chamber) 12 are formed in the rear head 3.

The suction chamber 13 is located around the discharge chamber 12. The suction chamber 13 contains a low-pressure refrigerant gas to be supplied to the compression chamber 22. The discharge chamber 12 contains the high-pressure refrigerant gas discharged from the compression chamber 22.

An insertion hole 81 for the bolt 19 is formed at the center of the valve plate 2, and a discharge port 1 for communicating the compression chamber 22 and the discharge chamber 12 around the insertion hole 81.
6 and suction ports 15 for communicating the compression chamber 22 and the suction chamber 13 are provided at predetermined intervals along the circumferential direction. The suction port 15 and the discharge port 16 are respectively located inside the opening edge 6a of the cylinder bore 6, and the suction port 15 is located outside the discharge port 16 (radially outside the valve plate 2). The suction port 15 is opened and closed by a suction valve 21.
Are arranged on the front end face of the vehicle. The discharge port 16 is opened and closed by a discharge valve 17, and the discharge valve 17 is fixed to the rear head side end surface 2 a of the valve plate 2 by a bolt 19 together with a valve retainer 18. As shown in FIG. 2A, a hole 80 of a perfect circle larger than the cross-sectional area of the discharge port 16 is formed at the periphery of the opening of the discharge port 16 on the rear head side of the valve plate 2. The hole 80 has a mortar shape (see FIG. 2B), guides the refrigerant gas in the discharge port 16 to the discharge chamber 12, and discharges the gas from the discharge valve 17 to be described later.
(See FIGS. 1 and 3).

An insertion hole 91 for a bolt 19 is formed in the center of the discharge valve 17 to open and close the discharge port 16.
0 is formed radially around the insertion hole 91 (see FIGS. 2 and 3). A substantially hemispherical guide protrusion 92 for guiding the refrigerant gas in the discharge port 16 to the discharge chamber 12 is formed at the tip of the opening / closing portion 90 (see FIGS. 1 and 3).

The number of the opening / closing portion 90 of the suction valve 21, the discharge valve 17, the suction port 15, the discharge port 16, and the number of the compression chambers 22 are as follows.
Each is equal to the number of cylinder bores 6 (7 in this embodiment).

One end of the shaft 5 is rotatably supported by the front head 4 via a radial bearing 26, and the other end of the shaft 5 is a radial bearing 25 and a thrust bearing 24.
And is rotatably supported by the cylinder block 1 via the.

A communication passage (not shown) is provided between the suction chamber 13 and the crank chamber 8, and an orifice (not shown) is provided in the middle of the communication passage. The discharge chamber 12
A communication path (not shown) is provided between the motor and the crank chamber 8, and a pressure adjusting valve (not shown) is provided in the middle of the communication path, and the pressure in the crank chamber 8 is adjusted by the pressure adjusting valve. The communication passage is opened and closed.

A winding spring 47 is mounted between the thrust flange 40 and the swash plate 10, and the swash plate 10 is urged rearward by the urging force of the winding spring 47. A winding spring 48 is mounted between the swash plate 10 and the thrust bearing 24, and the swash plate 10 is urged toward the front side by the urging force of the winding spring 48.

Next, the operation of the variable displacement type swash plate type compressor will be described.

When the rotational power of the vehicle-mounted engine (not shown) is transmitted to the shaft 5, the rotational force of the shaft 5 is transmitted to the swash plate 10 through the thrust flange 40, and the swash plate 10 rotates. Due to the rotation of the swash plate 10, the shoes 60 and 61 relatively rotate on the sliding surfaces 10a and 10b of the swash plate 10,
Is converted into a linear reciprocating motion of the piston 7.

When the piston 7 reciprocates in the cylinder bore 6, the volume of the compression chamber 22 in the cylinder bore 6 changes, and the suction, compression and discharge of the refrigerant gas are sequentially performed by this volume change, and the inclination angle of the swash plate 10 The high-pressure refrigerant gas having a capacity corresponding to the pressure is discharged. At the time of suction, the suction valve 21 is opened, low-pressure refrigerant is sucked from the suction chamber 13 into the compression chamber 22 in the cylinder bore 6, and at the time of discharge, the discharge valve 17 is opened, and high-pressure refrigerant gas flows from the compression chamber 22 to the discharge chamber 12. Discharged.
The high-pressure refrigerant gas in the discharge chamber 12 is discharged from the discharge port 3a to a cooler (not shown).

In the suction stroke, as the piston 7 moves to the bottom dead center side, a large pressure difference is generated between the compression chamber 22 and the suction chamber 13, and the suction valve 21 is bent toward the compression chamber 22 and the suction port 15 is closed. open.

In the compression stroke, as the piston 7 moves to the top dead center, the volume of the compression chamber 22 gradually decreases,
The pressure in the compression chamber 22 increases. At this time, the guide projection 92 of the discharge valve 17 comes into surface contact with the mortar-shaped hole 80 and the discharge port 16 is closed by the discharge valve 17 as shown in FIG. Does not flow out to the discharge chamber 12. Discharge port 16 when discharge valve 17 is closed
The inner volume is smaller than when the mortar-shaped hole 80 is not formed in the discharge port 16, so that the dead volume is smaller.

In the discharge stroke, the volume of the compression chamber 22 is minimized, and the pressure in the compression chamber 22 is maximized. When a certain pressure difference occurs between the compression chamber 22 and the discharge chamber 12, the discharge valve 17 bends toward the discharge chamber 12, and the discharge port 16 is opened. At this time, the refrigerant gas in the compression chamber 22 passes through the discharge port 16 as shown in FIG. 4B, and is radially guided on the surface of the substantially hemispherical guide projection 92 of the discharge valve 17 to be discharged.
Fell out.

When the heat load decreases and the pressure regulating valve opens to increase the pressure in the crank chamber 8, the inclination angle of the swash plate 10 decreases, so that the stroke amount of the piston 7 decreases and the discharge capacity decreases. . On the other hand, when the heat load increases and the pressure regulating valve closes and the pressure in the crank chamber 8 decreases, the inclination angle of the swash plate 10 increases, so that the stroke amount of the piston 7 increases and the displacement increases. .

According to this embodiment, when the refrigerant is discharged, the refrigerant gas is guided to the guide projection 92 of the discharge valve 17 and flows out to the discharge chamber 12. Since the discharge resistance of the refrigerant gas decreases,
Compressor efficiency can be improved.

Further, since the dead volume is reduced, the volume efficiency can be improved.

In the above-described embodiment, the variable displacement type swash plate type refrigerant compressor has been described as an example of the reciprocating type refrigerant compressor. The present invention can be applied.

[0041]

As described above, according to the reciprocating refrigerant compressor of the first aspect of the invention, the discharge resistance of the refrigerant gas is reduced, so that the compressor efficiency can be improved.

According to the reciprocating refrigerant compressor of the second aspect of the present invention, the dead volume is reduced, so that the volume efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a variable displacement swash plate type compressor according to an embodiment of the present invention.

FIG. 2 is a diagram for explaining a valve plate.

FIG. 3 is a diagram for explaining a discharge valve.

FIG. 4 is a diagram for explaining the operation of a discharge valve.

[Explanation of symbols]

 Reference Signs List 1 cylinder block 2 valve plate 3 rear head (cylinder head) 6 cylinder bore 12 discharge chamber (high-pressure chamber) 16 discharge port 17 discharge valve 22 compression chamber 80 hole 92 guide projection

Claims (2)

[Claims] 1. A cylinder block having a cylinder bore, a compression chamber formed in the cylinder bore and compressing a refrigerant, and a high-pressure chamber fixed to one end of the cylinder block and through which the refrigerant from the compression chamber flows. And a valve plate disposed between the cylinder block and the cylinder head and having a discharge port communicating the compression chamber and the high-pressure chamber. A reciprocating refrigerant compressor, wherein a refrigerant as a working fluid is carbon dioxide, wherein the refrigerant is supplied to the discharge valve when the discharge valve is opened. A reciprocating refrigerant compressor having a substantially hemispherical guide projection for guiding to a high-pressure chamber. 2. The reciprocating device according to claim 1, wherein a hole is formed in a peripheral edge of the high pressure chamber side opening of the discharge port so that the guide protrusion comes into surface contact when the discharge valve is closed. Type refrigerant compressor.