JPH11173274A - Variable displacement type swash plate compressor without clutch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a variable displacement type swash plate compressor without clutch which can facilitate seal management to outside air, restrain noise, and improve reliability. SOLUTION: A delivery control valve 30 is placed on the way of a delivery passage 39 guiding refrigerant gas from a delivering chamber 12 to a delivery port 1a, and when pressure difference in between a suction chamber 13 and the delivering chamber 12 is less than a given value, the delivery control valve 30 cuts off the delivery passage 39. As a result, flow out of refrigerant gas from the delivery port 1a to a capacitor 84 is prevented, and the refrigerant gas circulates internally. Since a mechanism for internally circulating the refrigerant gas is not required to be mounted to a shaft 5, the suction chamber 13 can be placed outside of the delivering chamber 12 in rear head 3. In addition, since sufficient preload can be loaded on the shaft 5, the shaft 5 stabilizes axially.

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 clutchless compressor, and more particularly to a variable displacement swash plate type clutchless compressor to which the driving force of an engine is constantly transmitted.

[0002]

2. Description of the Related Art As a conventional clutchless compressor, there is a variable displacement swash plate type clutchless compressor. In this clutchless compressor, the inclination angle of the swash plate changes according to the suction pressure, and the stroke of the piston changes.
The discharge amount increases or decreases.

When a variable displacement swash plate type clutchless compressor in which the minimum discharge capacity does not become zero is adopted as the clutchless compressor, the evaporator is cooled by the refrigerant when the heat load is reduced (when the clutch with the clutch is turned off). In some cases, frost is formed on the surface of the evaporator, and the evaporator freezes to make ventilation difficult, thereby impairing the cooling function.

[0004] As a technique for preventing this, there is a technique that circulates a refrigerant inside a compressor when the heat load is reduced to make the amount of discharge to the outside of the compressor zero (Japanese Patent Laid-Open No. 7-253080).

In this clutchless compressor, the inclination angle of the swash plate decreases as the thermal load decreases, and the swash plate pushes the transmission cylinder to the rear side, and the transmission cylinder pushes the breaker to the rear side. When the swash plate is most inclined, the shut-off body closes the suction passage, and the inflow of low-pressure refrigerant gas from the evaporator is prevented. On the other hand, the discharge chamber and the crank chamber are communicated by the control valve, and the high-pressure refrigerant gas in the discharge chamber flows to the crank chamber, and the refrigerant gas hardly flows to the condenser side. Thus, when the inclination angle of the swash plate is minimum (at the time of the minimum piston stroke), most of the refrigerant gas circulates inside the compressor, and the refrigeration capacity can be made zero. Further, since the refrigerant gas circulates internally, the sliding portion is sufficiently lubricated and cooled.

[0006]

However, since a structure is employed in which a transmission cylinder and a blocking member for closing the suction passage are mounted on the rotating shaft, the discharge chamber (high-pressure chamber) is provided in the cylinder head. (Low-pressure chamber), it must be arranged outside, and the management of the seal with the outside air becomes strict. For example, higher processing accuracy and a proper tightening amount of bolts (bolts for connecting the cylinder block and the head) are required.

Further, since a structure is employed in which a preload is applied to the rotary shaft by a spring via a transmission cylinder, a bearing, and a blocking body, a sufficient preload cannot be applied to the rotary shaft due to its structure. As a result, the rotating shaft and the rotating support are not stabilized in the axial direction, and noise due to vibration increases. In particular, when the load is large under a high load, the spring for urging the breaker is elongated, and the noise is further increased.

Further, since the blocking body rotates with the rotation of the rotating shaft, the spring for urging the blocking body rotates together with the blocking body to cut off the thread, so that the suction passage cannot be opened and closed.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and its object is to make it easy to manage the seal against the outside air, to suppress noise, and to improve the reliability. An object of the present invention is to provide a plate-type clutchless compressor.

[0010]

According to a first aspect of the present invention, there is provided a variable displacement type swash plate type clutchless compressor which is slidably and tiltably mounted on a rotating shaft and integrated with the rotating shaft. A swash plate, a crank chamber containing the swash plate, a suction chamber containing refrigerant gas to be sent to the compression chamber, a first passage communicating the crank chamber with the suction chamber, and the compression chamber. A discharge chamber for accommodating the refrigerant gas discharged from the discharge chamber, a discharge port for sending the refrigerant gas from the discharge chamber to the condenser side, a discharge passage for guiding the refrigerant gas in the discharge chamber to the discharge port, the discharge chamber and the discharge chamber. A variable displacement type inclined valve comprising: a second passage communicating with the crank chamber; and a pressure control valve provided in the middle of the second passage and shutting off the second passage when a thermal load increases. Plate type clutchless compressor In, provided in the middle of the discharge passage, characterized in that the differential pressure between the suction chamber and the discharge chamber is provided with said discharge passage is closed discharge control valve when it is below a predetermined value.

When the pressure difference between the suction chamber and the discharge chamber becomes equal to or less than a predetermined value, the discharge passage is shut off by the discharge control valve.
As a result, the refrigerant gas is prevented from flowing out from the discharge port to the condenser, and the refrigerant gas circulates internally.

According to a second aspect of the present invention, there is provided a variable displacement type swash plate type clutchless compressor according to the first aspect, wherein the discharge control valve is a spool valve. The pressure of the suction chamber and the urging force of the urging member act on one of the spool valves, and the pressure of the discharge chamber acts on the other of the spool valves.

The spool valve linearly reciprocates according to the difference between the pressure in the suction chamber, the biasing force of the biasing member and the pressure in the discharge chamber, and opens and closes the discharge passage.

[0014]

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 swash plate type clutchless compressor according to an embodiment of the present invention.
FIG. 2 is an arrow view along the line II-II in FIG.

A rear head 3 is fixed to one end surface of a cylinder block 1 of the variable displacement type swash plate type clutchless compressor via a valve plate 2, and a front head 4 is fixed to the other end surface. The cylinder block 1 is provided with a plurality of cylinder bores 6 at predetermined intervals in a circumferential direction around a shaft (rotating shaft) 5. A piston 7 is slidably accommodated in each of the cylinder bores 6. The cylinder block 1 is provided with a discharge port 1a communicating with the inlet of the condenser 84.

A crank chamber 8 is provided in the front head 4.
A swash plate 10 is accommodated in the crank chamber 8. A shoe 50 that supports the spherical end portion 11a of the connecting rod 11 so as to be relatively rotatable is held by a retainer 53 on the sliding surface 10a of the swash plate 10. A bearing 55 is mounted on the boss 10b of the swash plate 10,
The retainer 53 is connected to the boss 10 of the swash plate 10 via a bearing 55.
b, the retainer 53 is rotatable relative to the swash plate 10. The bearing 55 is prevented from coming off by a stopper 54 fixed to the boss 10b. The other end 11 b of the connecting rod 11 is fixed to the piston 7.

The shoe 50 is connected to the connecting rod 11.
A shoe body 51 that supports the tip end surface of one end 11a of the connecting rod 11 so as to be able to relatively roll, and one end 11 of the connecting rod 11
a and a washer 52 that supports the rear end surface of the a.

A discharge chamber 12 and a suction chamber 13 are formed in the rear head 3. The suction chamber 13 is arranged so as to surround the discharge chamber 12 (see FIG. 2). The rear head 3 has a suction port 3a leading to an outlet of an evaporator (not shown).
Is provided. Rear head 3 and valve plate 2
Is provided with a discharge passage 39 communicating between the discharge port 1a and the discharge chamber 12.

FIG. 3 is an enlarged longitudinal sectional view showing a state in which the discharge passage 39 is open, and FIG. 4 is an enlarged longitudinal sectional view showing a state in which the discharge passage 39 is closed.

A discharge control valve 30 is provided in the middle of the discharge passage 39. The discharge control valve 30 includes a bottomed cylindrical spool valve 31, a spring (biasing member) 32, and a stopper 5.
6 is provided. The stopper 56 is fixed to the rear head 3 with a cap 59, the spring 32 is housed in the spool valve 31, one end of the spring 32 contacts the stopper 56, and the other end of the spring 32 contacts the bottom surface of the spool valve 31. . The internal space 33 of the spool valve 31 communicates with the suction chamber 13 via a cap 59 and a passage 83 provided in the rear head 3.

The biasing force of the spring 32 and the pressure of the suction chamber 13 act on one of the spool valves 31 in the valve closing direction (the direction in which the valve opening decreases). The pressure in the discharge chamber 12 acts on the other side of the spool valve 31 in the opening and closing valve direction (the direction in which the valve opening increases).

FIG. 3 is an enlarged longitudinal sectional view showing a state in which the discharge passage is opened.

The discharge chamber 12 and the crank chamber 8 communicate with each other through a passage (second passage) not shown. A control valve (pressure control valve) 81 is provided in the middle of the passage. The control valve 81 closes only when the heat load is large.

The suction chamber 13 and the crank chamber 8 pass through a passage (first
(Path 58). The passage 58 includes an orifice 58a formed in the valve plate 2 and a passage 58b formed in the cylinder block 1.

The valve plate 2 has a discharge port 16 for communicating the compression chamber 82 and the discharge chamber 12 and a suction port 15 for communicating the cylinder bore 6 and the suction chamber 13 at predetermined intervals in the circumferential direction. Is provided.
The discharge port 16 is opened and closed by a discharge valve 17, and the discharge valve 1
7 is a valve retainer 1 on the end face of the valve plate 2 on the rear head side.
8 together with bolts 19 and nuts 20. The suction port 15 is opened and closed by a suction valve 21, and the suction valve 21 is disposed between the valve plate 2 and the cylinder block 1.

The radial bearing 24 and the thrust bearing 25 support the rear side of the shaft 5, and the front side of the shaft 5 is rotatably supported by a radial bearing 26. An internal thread 1b is provided at the center of the cylinder block 1, and an adjust nut 83 is screwed into the internal thread 1b. By tightening the adjustment nut 83, a preload is applied to the shaft 5 via the thrust bearing 25. A pulley 90 is fixed to a front end of the shaft 5 with bolts 92, and a belt 91 is hung on the pulley 90.

The shaft 5 is rotated by the swash plate 1.
The thrust flange 40 for transmitting to zero is fixed,
The thrust flange 40 is supported on the inner wall surface of the front head 4 via a thrust bearing 33. The thrust flange 40 and the swash plate 10 are connected via a hinge mechanism 41, and the swash plate 10 can be inclined with respect to a plane perpendicular to the shaft 5.

The swash plate 10 is mounted on the shaft 5 so as to slide and tilt.

The hinge mechanism 41 includes a bracket 10e provided on the front surface 10c of the swash plate 10 and a bracket 1
0e and a rod 4 screwed into the swash plate side end surface 40a of the thrust flange 40.
3 is comprised. The longitudinal axis of the guide groove 10f is inclined at a predetermined angle with respect to the front surface 10c of the swash plate 10.
The spherical portion 43a of the rod 43 is fitted into the guide groove 10f so as to be relatively slidable.

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

The rotational power of the vehicle-mounted engine (not shown) is constantly transmitted to the pulley 90 and the shaft 5 via the belt 91, and the rotational force of the shaft 5 is transmitted to the swash plate 10 via the thrust flange 40 and the hinge mechanism 41. 10 rotates.

The rotation of the swash plate 10 causes the shoe 50 to move to the swash plate 1.
The rotation of the piston 7 is converted to a linear reciprocating motion of the piston 7 because the rotation is relatively performed on the rear surface 10a of the zero. The piston 7 reciprocates in the cylinder bore 6, and as a result, the volume of the compression chamber 82 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 is changed. A refrigerant gas having a corresponding capacity is discharged. At the time of suction, the suction valve 21 opens, and low-pressure refrigerant is sucked from the suction chamber 13 into the compression chamber 82 in the cylinder bore 6, and at the time of discharge, the discharge valve 17 opens, and high-pressure refrigerant gas flows from the compression chamber 82 to the discharge chamber 12. Discharged.

When the heat load is reduced (corresponding to the clutch-off state of the compressor with a clutch), the control valve 81 is opened, high-pressure refrigerant gas flows from the discharge chamber 12 to the crank chamber 8, and the pressure in the crank chamber 8 increases. Then, the force applied to the front surface of the piston 7 during the compression stroke increases, and the sum of the forces applied to the front surface of the piston 7 exceeds the sum of the forces applied to the rear surface of the piston 7.
The inclination angle of the swash plate 10 becomes smaller.

The pressure difference between the suction chamber 13 and the discharge chamber 12 becomes equal to or less than a predetermined value (for example, 1.5 MPa) P 1, and the pressure of the suction chamber 13 acting on the spool valve 31 of the discharge control valve 30 and the urging force of the spring 32 When the resultant force overcomes the pressure of the discharge chamber 12 by the spool valve 31, the spool valve 31 moves in the valve closing direction to close the discharge passage 39 (see FIG. 3). As a result, the discharge port 1a
The refrigerant gas is prevented from flowing out to the condenser 84.

When the inclination angle of the swash plate 10 is at a minimum,
The refrigerant gas returns to the suction chamber 13 through the suction chamber 13, the compression chamber 82, the discharge chamber 12, the control valve 81, the crank chamber 8, and the passage 58 in order.

On the other hand, when the heat load increases, the control valve 81 closes, and the inflow of the high-pressure refrigerant gas from the discharge chamber 12 to the crank chamber 8 is prevented.
Pressure is lower. Then, the force applied to the front surface of the piston 7 during the compression stroke becomes smaller, and the sum of the forces applied to the front surface of the piston 7 becomes smaller than the sum of the forces applied to the rear surface of the piston 7, so that the inclination angle of the swash plate 10 becomes smaller. growing.

When the pressure in the suction chamber 13 decreases and the pressure difference between the suction chamber 13 and the discharge chamber 12 exceeds a predetermined value P2, the pressure in the discharge chamber 12 acting on the spool valve 31 increases. Overcoming the resultant force of the acting pressure of the suction port chamber 13 and the urging force of the spring 32, the spool valve 31 moves in the valve opening direction, and the discharge passage 39 opens. As a result, the discharge chamber 12
Is sent out from the discharge port 1a to the inlet of the condenser 84.

According to the variable displacement type swash plate type clutchless compressor of this embodiment, there is no need to mount a mechanism for opening and closing the suction passage (such as a conventional transmission cylinder or blocker) on the shaft 5. In this case, the suction chamber 13 can be disposed outside the discharge chamber 12, and the management of the seal with the outside air becomes easy. Furthermore, since the spring for applying a preload to the shaft 5 rotates with the rotation of the shaft 5 and is cut off, the opening and closing of the suction passage cannot be prevented.
The reliability of the compressor is improved.

Further, since a sufficient preload can be applied to the shaft 5 by tightening the adjusting nut 83, the shaft 5 and the thrust flange 40 are stabilized in the axial direction, and noise due to vibration can be suppressed.

Further, since the structure of the cylinder block 1 and the like is not complicated, parts can be shared with the variable displacement type swash plate type compressor with clutch.

Since the spool valve 31 is employed as the discharge control valve, the structure can be simplified.

In the above embodiment, the discharge control valve 3
Although the case where the spool valve 31 is used as 1 has been described, a valve other than the spool valve such as a rotary valve may be used.

[0044]

As described above, according to the variable displacement type swash plate type clutchless compressor according to the first aspect of the present invention, it is not necessary to mount a mechanism for opening and closing the suction passage on the rotating shaft by employing the discharge control valve. Since the suction chamber can be arranged outside the discharge chamber in the housing, the management of the seal with the outside air is facilitated. Further, the spring for applying a preload to the rotary shaft is not twisted due to the rotation of the rotary shaft and cannot be opened and closed, so that the reliability of the compressor is improved.

Further, since a sufficient preload can be applied to the rotating shaft, the rotating shaft is stabilized in the axial direction, and noise due to vibration can be suppressed.

According to the variable displacement type swash plate type clutchless compressor according to the second aspect of the present invention, since the spool valve is employed as the suction control valve, the structure can be simplified.

[Brief description of the drawings]

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

FIG. 2 is a view taken along line II-II in FIG.

FIG. 3 is an enlarged vertical sectional view showing a state in which a discharge passage is opened.

FIG. 4 is an enlarged longitudinal sectional view showing a state in which a discharge passage is closed.

[Explanation of symbols]

 1a Discharge port 5 Shaft 8 Crank chamber 10 Swash plate 12 Discharge chamber 13 Suction chamber 30 Discharge control valve 31 Spool valve 32 Spring 58 Passage 39 Discharge passage 81 Control valve 82 Compression chamber 84 Condenser

Claims (2)

[Claims] 1. A slidable and tiltably mounted rotating shaft,
A swash plate that rotates integrally with the rotating shaft, a crank chamber that stores the swash plate, a suction chamber that stores a refrigerant gas to be sent to a compression chamber, and a first communication port that connects the crank chamber to the suction chamber.
, A discharge chamber accommodating the refrigerant gas discharged from the compression chamber, a discharge port for sending the refrigerant gas from the discharge chamber to the condenser side, and a discharge passage for guiding the refrigerant gas of the discharge chamber to the discharge port. A second passage for communicating the discharge chamber with the crank chamber, a pressure control valve provided in the middle of the second passage, and shutting off the second passage when a thermal load increases. A variable displacement swash plate type clutchless compressor comprising: a discharge control valve provided in the middle of the discharge passage to close the discharge passage when a differential pressure between the suction chamber and the discharge chamber becomes equal to or less than a predetermined value. A variable displacement swash plate type clutchless compressor characterized by comprising: 2. The discharge control valve is a spool valve, and the pressure of the suction chamber and the urging force of an urging member act on one of the spool valves, and the pressure of the discharge chamber acts on the other of the spool valves. 2. The variable displacement swash plate type clutchless compressor according to claim 1, wherein said compressor operates.