JP2001003860A - Variable displacement swash plate compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a variable displacement swash plate compressor capable of improve the reliability of a shaft seal. SOLUTION: A variable displacement swash plate compressor comprises a shaft 5 rotatably equipped to a shell 30 through a radial bearing 26; a crank chamber 8 formed in the shell 30 and storing a swash plate 10 for deciding the stroke amount of a piston 7; a low pressure chamber 70 disposed next to a front side of the crank chamber 8 and storing low pressure refrigerant gas from an outlet side of an evaporator; and a U-ring 73 sealing an interior space of the low pressure chamber 70 and an interior space of the crank chamber 8. A mechanical seal 72 sealing the interior space of the low pressure chamber 70 and outside air is stored in the low pressure chamber 70. Therefore, compared with the case where the mechanical seal 72 is stored in the crank chamber 8, a load applying out the mechanical seal 72 by pressure of the refrigerant gas is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable displacement swash plate type compressor, and more particularly to a variable displacement type swash plate type compressor suitable as a vehicle refrigerant compressor using CO2 as a refrigerant.

[0002]

2. Description of the Related Art FIG. 2 is a longitudinal sectional view showing a conventional variable displacement swash plate type compressor.

The variable displacement type swash plate compressor includes a front head 104, a cylinder block 101, a rear head 1
03, a shaft 105, a thrust flange 140, a swash plate 110, a plurality of pistons 107, and the like.

The front head 104 is fixed to the front end surface of the cylinder block 101, and the rear head 103
Is the cylinder block 10 via the valve plate 102.
1 is fixed to the rear end face. Front head 10
4, a crank chamber 108 for accommodating the swash plate 110 and the like is formed. The rear head 103 includes a compression chamber 12.
Suction chamber 113 containing a low-pressure refrigerant gas to be supplied to fuel cell 2
And a discharge chamber 112 for accommodating the high-pressure refrigerant gas discharged from the compression chamber 122, respectively.

[0005] The cylinder block 101 is provided with a plurality of cylinder bores 106.

[0006] One end of the shaft 105 is a radial bearing 1
The other end of the shaft 105 is rotatably supported by the cylinder block 101 via a radial bearing 125 and a thrust bearing 124.

[0007] The thrust flange 140 is connected to the shaft 10.
5 and rotates integrally with the shaft 105.

The swash plate 110 is attached to the shaft 105 so as to be inclined and slidable. Also, the swash plate 110
The thrust flange 140 is connected to the thrust flange 140 via a link mechanism 141, and integrally rotates as the thrust flange 140 rotates.

[0009] The piston 107 is slidably inserted into the cylinder bore 106. One end of the piston 107 and the peripheral edge of the swash plate 110 are connected via shoes 160 and 161. A pair of shoes 160, 161 is arranged for each piston 107 so as to sandwich the peripheral edge of the swash plate 110, and the shoes 160, 161 are rotatably supported by one end of the piston 107. Shoe 160, 1
Numeral 61 relatively rotates on the sliding surfaces 110a and 110b of the swash plate 110 as the shaft 105 rotates.

When the rotational power of a vehicle-mounted engine (not shown) is transmitted to the shaft 105, the rotational force of the shaft 105 is transmitted from the thrust flange 140 to the swash plate 110 via the link mechanism 141, and the swash plate 110 rotates.

The rotation of the swash plate 110 causes the shoes 160, 1
61 rotates relatively on the sliding surfaces 110a and 11b of the swash plate 110, and the rotational force from the swash plate 110 is converted into a linear reciprocating motion of the piston 107. When the piston 107 reciprocates in the cylinder bore 106, the volume of the compression chamber 122 in the cylinder bore 106 changes, and the suction, compression, and discharge of the refrigerant gas are sequentially performed by the change in the volume. Swash plate 110
The inclination angle of the swash plate 110 changes according to the change in the pressure in the crank chamber 108 in which the swash plate 110 is accommodated, so that high-pressure refrigerant gas having a capacity corresponding to the inclination angle of the swash plate 110 is discharged.

When the pressure in the crank chamber 108 increases, the inclination angle of the swash plate 110 decreases, so that the piston 107
And the discharge amount decreases.

On the other hand, when the pressure in the crank chamber 108 decreases, the inclination angle of the swash plate 110 increases.
The stroke amount of the piston 107 increases and the discharge capacity increases.

[0014]

As described above, the inclination angle of the swash plate 110 changes in accordance with the change in the pressure in the crank chamber 108. However, the space between the internal space of the crank chamber 108 and the atmosphere serves as a shaft seal. Since it is sealed by the mechanical seal 173, the refrigerant does not leak into the atmosphere.

However, when the refrigerant is CO 2, the pressure in the crank chamber 108 is significantly higher (for example, about 60 km / cm 2) than when the refrigerant is Freon, so that the load on the mechanical seal 173 is large, and 173 was easily damaged.

Since the lubricating oil in the refrigerant is not sufficiently supplied to the mechanical seal 173, the mechanical seal 1
The sealability of No. 73 was not good.

The present invention has been made in view of such circumstances, and an object thereof is to provide a variable displacement type swash plate compressor capable of improving the reliability of a shaft seal.

[0018]

According to a first aspect of the present invention, there is provided a variable displacement swash plate type compressor according to the first aspect of the present invention, wherein a shaft rotatably mounted on a housing via a bearing, and a shaft inside the housing. A crank chamber in which a swash plate that determines the stroke amount of the piston is housed, a low-pressure chamber that is arranged adjacent to the front side of the crank chamber and houses a low-pressure refrigerant gas, and an internal space of the low-pressure chamber. A first seal member for sealing an internal space of the crank chamber;
A second sealing member that is housed in the low-pressure chamber and seals an internal space of the low-pressure chamber and the atmosphere.

Since the second seal member is housed in the low-pressure chamber as described above, the second seal member is housed in the low-pressure chamber.
The load on the seal member is reduced.

According to a second aspect of the present invention, there is provided the variable displacement type swash plate type compressor according to the first aspect of the present invention, wherein a part of the bearing faces the internal space of the low pressure chamber. It is characterized by being.

As described above, since a part of the bearing faces the internal space of the low-pressure chamber, the bearing is cooled and lubricated by the low-temperature lubricating oil in the refrigerant gas.

According to a third aspect of the present invention, there is provided a variable displacement type swash plate type compressor according to the first or second aspect, wherein the refrigerant is carbon dioxide.

When the refrigerant is carbon dioxide, the pressure in the crank chamber is significantly higher than when the refrigerant is Freon.
Since the first seal member is housed in the low-pressure chamber, the load on the first seal member due to the pressure of the refrigerant is small.

[0024]

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

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

This variable displacement swash plate compressor is used as one component of a refrigeration system using CO2 (carbon dioxide) as a refrigerant. A rear head 3 is arranged on one end surface of a cylinder block 1 of the variable displacement type swash plate type compressor via a valve plate 2, and a shell (housing) 30 is arranged on the other end surface. The front head 4 is disposed on a front end surface of the shell 30 via a gasket 74. The front head 4, shell 30, cylinder block 1, valve plate 2 and rear head 3
1 and the nut 32 are integrally connected in the axial direction.

A plurality of cylinder bores 6 are formed in the cylinder block 1 at predetermined intervals along a circumference around the shaft 5. A piston 7 is slidably inserted into each cylinder bore 6. At one end of the piston 7, concave portions 51a and 51b that rotatably support a pair of shoes 60 and 61 described later are formed.

The crank chamber 8 for accommodating the swash plate 10 and the thrust flange 40 described later is formed in the shell 30. The rear head 3 has a suction chamber 13 and a discharge chamber 12.
Are formed. 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 has a compression chamber 22.
The high-pressure refrigerant gas discharged from is accommodated.

One end of the shaft 5 is rotatably supported by the shell 30 via a radial bearing (bearing) 26, and the other end of the shaft 5 is rotatable by the cylinder block 1 via a radial bearing 25 and a thrust bearing 24. It is supported by. The radial bearing 26 is a boss 30a of the shell 30.
Located between the inner peripheral surface of the center hole and the outer peripheral surface of the shaft 5,
The U-ring (first seal member) 73 is the radial bearing 26
The space between the internal space of the crank chamber 8 and the internal space of the low-pressure chamber 70 is sealed by the U-ring 73.

The thrust flange 40 is fixed to the shaft 5 and rotates integrally with the shaft 5. The swash plate 10 is attached to the shaft 5 so as to be inclined and slidable. Further, the swash plate 10 is connected to the thrust flange 40 via the link mechanism 41, and integrally rotates as the thrust flange 40 rotates.

The periphery of the swash plate 10 and one end of the piston 7 are connected via shoes 60 and 61. Shoe 6
0 and 61 are convex (spherical) surfaces 60a and 61a and flat surfaces 60b and
61b. The convex surfaces 60a and 61a are in contact with the concave surfaces 51a and 51b at one end of the piston 7, and the flat surfaces 60b and 61b are in contact with the sliding surfaces 10a and 10b of the swash plate 10. A pair of shoes 6 for each piston 7
0 and 61 are arranged so as to sandwich the peripheral edge of the swash plate 10, and the shoes 60 and 61 relatively rotate on the sliding surfaces 10 a and 10 b of the swash plate 10 as the shaft 5 rotates. The rotation of the swash plate 10 causes the piston 7 to reciprocate in the cylinder bore 6.

The valve plate 2 has a discharge port 16 for communicating the compression chamber 22 and the discharge chamber 12, and a suction port 15 for communicating the compression chamber 22 and the suction chamber 13, each having a predetermined interval along the circumferential direction. It is provided every other. The discharge port 16 is opened and closed by a discharge valve 17, and the discharge valve 17 is fixed to a rear head side end surface of the valve plate 2 by a bolt 19 together with a valve retainer 18. The suction port 15 is opened and closed by a suction valve 21, and the suction valve 21 is disposed on a front end surface of the valve plate 2.

A communication path (not shown) is provided between the discharge chamber 12 and the crank chamber 8, and a pressure regulating valve (not shown) which opens and closes in response to a change in suction pressure is provided in the communication path. The pressure in the crank chamber 8 is adjusted by opening and closing the pressure adjusting valve.

A communication passage (not shown) is provided between the suction chamber 13 and the crank chamber 8, and an orifice is provided in the middle of the communication passage.

A thrust flange 40 fixed to the front end of the shaft 5 is rotatably supported on the inner wall surface of the shell 30 via a thrust bearing 33. As described above, the thrust flange 40 and the swash plate 10 are connected to the link mechanism 4.
1, the swash plate 10 can be inclined with respect to a plane perpendicular to the shaft 5. The link mechanism 41 includes the swash plate 10
Bracket 1 provided on the front sliding surface 10a of the vehicle
0c, a linear guide groove 10d formed in the bracket 10c, and a rod 43 screwed to the thrust flange 40. The longitudinal axis of the guide groove 10d is the swash plate 1.
It is inclined at a predetermined angle with respect to the zero sliding surface 10a. The spherical tip portion 43a of the rod 43 is fitted into the guide groove 10d so as to be relatively slidable.

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 winding springs 4.
The biasing force 8 biases the swash plate 10 toward the front.

A low-pressure chamber 70 is formed in the front head 4, and the low-pressure chamber 70 is connected to the suction chamber 11 through a guide passage 71.
Leads to. The low pressure chamber 70 has a low pressure (for example, about 40 km / cm 2) from a suction port 4 a formed in the front head 4.
・ Low-temperature refrigerant gas is stored. The guide passage 71 includes a passage 71 a formed in the shell 30 and the cylinder block 1.
, And a hole 71c formed in the valve plate 2.

A mechanical seal (second seal member) 72 is mounted on the outer peripheral surface of the front end of the shaft 5. The mechanical seal 72 seals the space between the low pressure chamber 70 and the atmosphere.

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

When the rotational power of a 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 via the thrust flange 40 and the hinge mechanism 41, and the swash plate 10 rotates.

The rotation of the swash plate 10 causes the shoes 60 and 61 to relatively rotate on the sliding surfaces 10a and 10b of the swash plate 10, and the rotational force from 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 refrigerant gas is changed according to the inclination angle of the swash plate 10. A volume of high-pressure refrigerant gas 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 the compression chamber 22 is opened.
, The high-pressure refrigerant gas is discharged to the discharge chamber 12. The high-pressure refrigerant gas in the discharge chamber 12 is discharged from the discharge port 3a to a cooler (not shown).

When the heat load is reduced and the pressure regulating valve is opened to increase the pressure in the crank chamber 8, the inclination angle of the swash plate 10 is reduced, so that the stroke of the piston 7 is reduced and the discharge capacity is reduced. . 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. .

During operation of the compressor, low-pressure and low-temperature refrigerant gas at the outlet side of the evaporator (not shown) flows into the low-pressure chamber 70 from the suction port 4a of the front head 4, passes through the guide passage 71, and flows into the suction chamber of the rear head 3. It reaches 13. At this time, the radial bearing 26 is cooled and lubricated by the low-temperature lubricating oil in the refrigerant gas. The pressure in the crank chamber 8 is low.
However, since the space between the internal space of the crank chamber 8 and the internal space of the low-pressure chamber 70 is sealed by the U-ring 73, refrigerant gas escapes from the crank chamber 8 to the low-pressure chamber 70. Absent.

According to the variable displacement type swash plate compressor of this embodiment, since the mechanical seal 72 is housed in the low-pressure chamber 70 as described above, the mechanical seal 72 is housed in the crank chamber 8. In comparison, the load on the mechanical seal 72 due to the pressure of the refrigerant gas is reduced, and the mechanical seal 72 is less likely to be damaged. As a result, the durability of the mechanical seal 72 is improved. Further, since the lubricating oil is sufficiently supplied to the mechanical seal 72, the sealing property of the mechanical seal 72 is improved.

A part of the radial bearing 26 is provided in the low-pressure chamber 7.
0, the radial bearing 26 is cooled and lubricated by low-temperature lubricating oil in the refrigerant gas, and the reliability of the radial bearing 26 is improved.

Further, since the low pressure chamber 70 is provided, the suction port 4
The refrigerant gas flowing from a repeats expansion and contraction before reaching the suction chamber 13, and low-pressure pulsation is reduced. as a result,
There is no need to provide a low-pressure muffler during the refrigeration cycle,
The cost of the refrigeration system can be reduced.

In the above-described embodiment, a swash plate (an annular body whose inclination changes in accordance with a change in the pressure of the crank chamber) is a swash plate compressor (a swash plate compressor) in which a swash plate (an annular body whose inclination changes according to a change in pressure of a crank chamber) rotates integrally with the shaft 5. A so-called one-sided swash plate type compressor was taken as an example. However, as another variable capacity type swash plate type compressor, a swinging plate type compressor in which the swash plate does not rotate integrally with the shaft 5 but swings as the shaft 5 rotates. The present invention can also be applied to a machine.

In the above embodiment, the shoes 60,
The present invention is applied to a variable displacement type swash plate type compressor having a structure in which 61 is directly supported by one end of a piston 7. However, the present invention is applied to a structure in which a connecting rod is interposed between the shoes 60, 61 and the piston 7. The invention can also be applied.

[0049]

As described above, according to the variable displacement type swash plate compressor of the first aspect of the present invention, the load on the second seal member due to the pressure of the refrigerant gas is reduced.
The seal member is less likely to be damaged, and the durability of the second seal member is improved. Further, since the lubricating oil is sufficiently supplied to the second seal member, the sealing property of the second seal member is improved.

According to the variable displacement type swash plate compressor of the second aspect of the present invention, the bearing is cooled and lubricated by the low-temperature lubricating oil in the refrigerant gas, so that the reliability of the radial bearing is improved.

According to the variable displacement type swash plate type compressor according to the third aspect of the present invention, when the refrigerant is carbon dioxide, the pressure in the crank chamber is significantly higher than when the refrigerant is Freon. Since the members are housed in the low pressure chamber,
The load on the second seal member due to the pressure of the refrigerant is not large. As a result, the second seal member is less likely to be damaged,
The durability of the sealing member is improved.

[Brief description of the drawings]

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

FIG. 2 is a longitudinal sectional view showing a conventional variable displacement swash plate type compressor.

[Explanation of symbols]

 Reference Signs List 5 shaft 7 piston 8 crank chamber 10 swash plate 26 radial bearing 30 shell 70 low-pressure chamber 72 mechanical seal 73 U-ring

Claims (3)

[Claims] 1. A crankshaft rotatably mounted on a housing via a bearing, a crank chamber formed in the housing and accommodating a swash plate that determines a stroke amount of a piston, and a front side of the crank chamber. A low-pressure chamber that is disposed adjacently and stores a low-pressure refrigerant gas; a first sealing member that seals an internal space of the low-pressure chamber and an internal space of the crank chamber; and a low-pressure chamber that is stored in the low-pressure chamber. A variable capacity type swash plate type compressor, comprising: a second seal member for sealing an internal space of the above and the atmosphere. 2. The variable displacement swash plate type compressor according to claim 1, wherein a part of said bearing faces an internal space of said low pressure chamber. 3. The variable displacement swash plate type compressor according to claim 1, wherein said refrigerant gas is carbon dioxide.