JPH03225099A - Variable displacement compressor - Google Patents

Abstract

PURPOSE:To enable minute displacement change corresponding to load so as to obtain high operating efficiency by opening by-pass holes communicated with the cylinder chamber of a compressor only by the required number so as to determine the displacement of the compressor stepwise. CONSTITUTION:A cylinder hole 30A is disposed to be approximately opposed to the upper part of one cylinder chamber 11A of a cylinder 11, and communicated, approximately at its center part, with the inside of the cylinder 11 by plural by-pass holes P3, P4, P5 formed at a rear plate 13 along the axis of the cylinder hole 30A. In the same way as the cylinder hole 3A, a cylinder hole 3A' is communicated, at its center part, with the inside of the cylinder 11 by three by-pass holes P3', P4', P5'. With the rotation of a roller 24, the communication between the cylinder chamber 11a and the by-pass holes P3, P4, P5 opened to the cylinder chamber 11A is cut off by the rotor 24 in turn starting from the inner by-pass hole P5, whereas the by-pass holes P3', P4', P5' are opened to a cylinder chamber 11B.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a compressor equipped with a variable capacity mechanism.

(Prior art) As a conventional variable capacity compressor of this type, there is a
There is one described in Japanese Patent No. 157084. As shown in FIG. 13, this conventional variable capacity compressor compresses refrigerant gas sucked in from a suction pipe 3 by a rotor 2 eccentrically rotating within a cylinder 1 and discharges the compressed gas from a discharge hole 9 (not shown).

When compressing refrigerant gas at full load, a bypass hole 4 is formed to open into the cylinder 1.
is closed by the valve 5, but when the compressor is operated under the retracted condition, the solenoid valve 6 is energized and the bypass hole 4 is opened by the valve 5, and the compressed refrigerant gas is passed through the bypass hole 4 and the bypass pipe. The water is refluxed to the suction pipe 3 via 7.

(Problem to be Solved by the Invention) However, in the conventional i■ variable displacement compressor as described above, the bypass pipe 7 for circulating the compressed refrigerant gas back to the suction pipe 3 is long when operating in unload mode. Therefore, when the rotation of the rotor 2 becomes high, there is a drawback that the unloading operation cannot be carried out efficiently due to the flow resistance of the refrigerant gas.

In addition, in this conventional variable capacity compressor, even though the capacity is variable, it is only possible to select either full load or unload capacity by turning the solenoid valve 6 on and off. It was not possible to make sufficient capacity changes to accommodate this.

This invention has been made in order to eliminate the drawbacks of the conventional variable displacement compressor described above. That is, it is an object of the present invention to provide a nI bag capacity compressor that has high operating efficiency in any variable capacity and can change the capacity sufficiently in accordance with the load.

(Means for Achieving the Object) In order to achieve the above object, the present invention provides a plurality of bypass holes opened in the cylinder chamber on the side whose volume is reduced as the rotor rotates, and a number of stages of bypass holes. It has a spool valve that opens and closes sequentially by sliding in the axial direction, and the discharge pressure from the cylinder chamber introduced into the first chamber formed on one side of the spool valve creates a bypass hole for the spool valve. A bypass that acts in a direction to close the spool valve, and suction pressure into the cylinder chamber introduced into a second chamber formed on the other side acts in a direction to open the bypass hole with respect to the spool valve and communicate with the second chamber. a control valve connected to the first chamber of the bypass valve and configured to reduce the discharge pressure introduced into the first chamber when the differential pressure between the suction pressure to the cylinder chamber and the atmospheric pressure is below a predetermined value. It is characterized by the presence of

In the second invention, the control valve has a third chamber communicating with the first chamber of the bypass valve, a fourth chamber into which suction pressure is introduced, and a difference between the suction pressure in the fourth chamber and atmospheric pressure. The device is characterized in that it includes communication means that cuts off communication between the third chamber and the fourth chamber when the pressure is above a predetermined value, and communicates between the third chamber and the fourth chamber when the pressure is below the predetermined value.

(effect) The variable displacement compressor has a bypass valve.

The spool valve is slid in the axial direction based on the difference between the discharge pressure and the suction pressure that act in opposite directions, and the number of bypass holes corresponding to the differential pressure, which are formed in the axial direction of the spool valve, is inserted into the spool valve. Open and close.

This bypass hole is communicated with the cylinder chamber on the side where the volume of the compressor is reduced as the rotor rotates, and when the cylinder chamber starts to be reduced, the fluid (for example, refrigerant gas) in this cylinder chamber is The fluid is discharged to the outside of the cylinder chamber through the open bypass hole, and the open bypass hole is blocked from communicating with the cylinder chamber by the rotating rotor, stopping the fluid from being discharged from the cylinder chamber. After that, compression of the fluid in the cylinder chamber starts. Therefore, until fluid compression starts in the cylinder chamber, the capacity of the compressor is reduced by the amount of discharged fluid, that is, by the amount corresponding to the number of bypass holes in the opened bypass valve. .

Then, the control valve operates according to the differential pressure between the suction pressure and atmospheric pressure.
When this differential pressure is large, the discharge pressure acting on the bypass valve is maintained as it is. As a result, the spool valve of the bypass valve is biased in the direction of closing the bypass hole, increasing the capacity of the compressor. Further, when the differential pressure between the suction pressure and the atmospheric pressure is small, the discharge pressure acting on the bypass valve is reduced to the suction pressure. As a result, the spool valve of the bypass valve is biased in the direction of opening the bypass holes, and the capacity of the compressor is reduced by the number of bypass holes that are opened.

(Example) Hereinafter, the present invention will be described in further detail based on an example shown in one drawing. Note that the following examples show two examples in which the present invention is implemented as a compressor for a car air conditioner.

In FIG. 1, a front plate 12 and a rear plate 13 are fixed to both sides of cylinder II. A front housing 14 is fixed to the opposite side of the front plate 12 from the cylinder 11. 4 and the front plate 12 between the suction chamber CI
is formed. Further, a rear housing 15 is fixed to the opposite side of the rear plate 13 from the cylinder 11.
A suction pressure chamber C2 is formed between the rear housing 15 and the rear plate 13. Furthermore, the rear housing 15 has a rear cover 1 on the side opposite to the rear plate 13.
6 is fixed, and a control pressure passage C3 is formed between it and the rear plate 15.

In the center of the front plate 12 is a bearing! A drive shaft 18 is rotatably supported by 7 so as to be coaxial with the cylinder 11, and furthermore, this drive shaft 1B is connected to the suction chamber C1.
It penetrates the front housing 14 and is sealed with the front housing 14 by a sealing material 19.

At the end of the drive shaft 18 on the cylinder 11 side, the cylinder 1
An eccentric shaft 18A that is eccentric from the axis of the cylinder 1 is integrally molded, and the end of the eccentric shaft 18A on the rear plate 13 side is connected to a shaft portion 18B that is rotatably supported on the rear plate I3 so as to be coaxial with the cylinder 11. Fitted and supported. Further, a front balancer 20 is attached to the drive shaft 18 in the suction chamber CI so as to rotate integrally with the drive shaft 18, and a rear balancer 21 is attached to the shaft portion 18B in the suction pressure chamber C2. installed,
It is configured to rotate integrally with the shaft portion 18B.

A discharge chamber C4 is formed in the upper and lower parts of the cylinder 11, and an I]L outlet hole P1 is formed in the outer wall of the cylinder 11 in the axial direction of the cylinder H. A number of (in this embodiment, three each) are formed.

8. A discharge valve 2 fixed in the discharge chamber C4 is provided in the 8 leaf outlet hole P1.
2 and the retainer 23 are arranged in correspondence with each other (the second
(see figure).

Further, the inside of the cylinder 11 and the suction chamber C1 are communicated through a suction hole P2 formed in the front plate 12.

Furthermore, as can be seen from FIG. 2, inside the cylinder 11,
A rotor 24 is disposed through the center of which is rotatably attached to the eccentric shaft 18A, and has the same width as the axial width of the cylinder 11. As the drive shaft 18 rotates, the eccentric shaft 18A
Due to the action of the rotor 24, its outer peripheral surface is aligned with the cylinder 1
The rotor 24 is configured to revolve within the cylinder 11 while contacting the inner circumferential surface of the rotor 24, and a parallel link mechanism (not shown) interposed between the rib 24a of the rotor 24 and the front play is regulated so that it does not rotate.

A pair of ribs 24 connect the central hub 24b and the outer peripheral wall 24c of the rotor 24 and oppose each other in the radial direction.
A pair of grooves 24e and 24e are formed in the grooves d and 24d, respectively, extending from the outer peripheral surface of the rotor 24 toward the center and having the same width as the axial width of the cylinder 11 along the axial direction. A pair of vanes 25, 25, each having the same width as the axial width of the cylinder 11, are fitted so as to be slidable in the radial direction.

The vane spring 2 disposed within the rotor 24
Both ends of the vanes 25 and 25 are inserted into the grooves 24e and 24e, respectively, and fit into the inner ends of the vanes 25 and 25, respectively.
5 radially outward. As a result, when the rotor 24 revolves, the outer ends of the vanes 25, 25 slide against the inner peripheral surface of the cylinder 11 while being pressed.
A space between the inner wall surface of the cylinder 11 and the outer peripheral surface of the rotor 24 is partitioned to form two cylinder chambers 11A and IIB.

As shown in FIG. 3, a pair of bypass valves 30 are provided on the outer periphery of the rear brake (rear brake) 13, each having cylinder holes 30A and 30A' extending perpendicularly to the axial direction of the cylinder 11.
and 30' are formed at symmetrical positions with respect to the axis of the rear plate 13.

The one cylinder hole 30A is arranged to almost face the upper part of the one cylinder chamber 11A of the cylinder 11, and as particularly shown in FIG. Rear plate 13
A plurality of (three in this embodiment) bypass holes P3. P4. It communicates with the inside of the cylinder 11 through P5, and further communicates with the suction pressure chamber c2 through a pressure guiding hole P6 formed in the rear plate 13 at the deepest part of the cylinder hole 30A. In addition, in FIG. 4, C5 is a discharge gas passage formed between the rear housing 15 and the rear cover 16.

Similarly to the one cylinder hole 30A, the other cylinder hole 30A' is connected to the cylinder 11 by three bypass holes P3', P4', and P5' in its center.
The innermost part thereof is connected to the suction pressure chamber C2 through a pressure guiding hole.

In FIGS. 3 and 4, a spool valve 3 (IB) is slidably inserted into the cylinder hole 30A, and a spring 30C interposed between the spool valve 30B and the cylinder hole 30A moves the opening direction. A plug 30 is inserted into the opening of the cylinder hole 30A.
D is fitted to prevent the spool valve 30B from popping out. Further, in a state where the spool valve 30B is biased by the spring 30C and in contact with the plug 300, a chamber C6 (first chamber) is formed between the spool valve 30B and the plug 30D; The spool valve 30B is connected to the bypass hole P3 located closest to the plug 30D.
7 (second chamber) is formed.

The other cylinder hole 30A' has the same structure as the cylinder hole 30A, and a spool valve 30B', a spring 300' and a plug 30D' are fitted therein.

A control valve 3I as shown in FIG. 5 is attached to an arbitrary position within the rear housing 15.
An inner cylinder 31C, which is fixed integrally with a plug 31B, is fitted into the cylinder hole 31A. The space formed between the inner wall of the cylinder hole 31A and the outer circumference of the inner cylinder 31C is airtightly divided into two chambers by the O-ring 31D attached to the outer circumference of the inner cylinder 31C. A chamber C8 (third chamber) is formed on the front end side of the inner cylinder 31C, and a chamber C9 is formed on the rear end side.

One of the chambers C8 communicates with the discharge chamber C4 formed in the cylinder 11 via a control pressure passage C3 and an orifice 32 formed between the rear housing 15 and the rear cover 16, and is connected to the discharge chamber C4 formed in the cylinder 11 through a control pressure passage C3 and an orifice 32. is being introduced.

The other chamber C9 includes a suction pressure chamber C2 formed in the rear housing 15 by the boat P8 and a bypass valve 3.
0.30' pressure guiding hole P6. P6' and chamber C7,
07'.

A long hole 31 extending in the axial direction is provided at the tip of the inner cylinder 31C.
E is formed, and the plug 31 of the inner cylinder 31C is
A cavity is formed in the B side fuselage, and the communication hole 3 is connected to each other.
It is connected by 1F. A ball 31G is movably inserted into the elongated hole 31E.
A plug 311 having a communication hole 31H in the axial direction is screwed into the tip opening of the spring 3 inserted between the plug 311 and the ball 31G in the elongated hole 31E.
1J, the ball 31G is urged in a direction to close the communication hole 31F.

A bellows 31K is installed in the cavity of the body of the inner cylinder 31C.
A bushing rod 31L is attached to the plug 31B so as to be movable in the axial direction.The bushing rod 31L is disposed with its tip end loosely fitted into the communication hole 31F. The inside and outside of the bellows 31 are airtightly divided, and a chamber Cl0 (
The fourth chamber) is connected to the inner cylinder 31 via the boat P9.
A communication hole 3 formed in the axial direction in the plug 31B is in communication with the chamber C9 outside C, and inside the bellows 31.
It is connected to the atmosphere by 1M. In addition, the communication hole 31
F also communicates with chamber C9 through hole 31N.

When the bushing rod 31L moves forward (leftward in the drawing), its tip presses the ball 31G and the spring 3
1J, the communication hole 31F is opened.

Also, the plug 30D of the bypass valve 30.30'.

30D' and the spool valves 30B, 30B' are connected to a discharge chamber C4 via a control pressure passage C3 and an orifice 32 formed between the rear housing 15 and the rear cover 16, respectively. The discharge pressure is introduced through the boat PIO.

Next, the operation of the variable displacement compressor will be explained with reference to FIGS. 6 to 12.

In the state shown in FIG. 6, one cylinder chamber 11A has the maximum volume,
The other cylinder chamber 11B is in the middle of suction, the cylinder chamber 11A has completed suction of gas from suction chamber C1 and has started compression, and the cylinder chamber 11B has completed compression and started suction of gas from suction chamber C1. Indicates the starting state. Note that in the state shown in FIG. 6, one row of bypass holes P3.
P4. P5 are all opened to the cylinder chamber 11A, and the bypass holes P3', P4', and P5' in the other row are all blocked from communicating with the cylinder chamber 11B by the rotor 24.

When the rotor 24 revolves in the clockwise direction (arrow X in the drawing) due to the rotation of the drive shaft 18 and the eccentric shaft 18A, the cylinder chamber l
When the volume of IA is reduced and the gas in the cylinder chamber 11A is compressed and the pressure rises to a predetermined pressure or higher, the discharge valve 22 installed in the discharge chamber C4 opens and gas is discharged from the cylinder chamber 11A. It is discharged into the discharge chamber C4 through the hole P1.

Further, the cylinder chamber 11B increases its volume and sucks gas from the suction chamber C1 through the suction hole P2.

Also, as the rotor 24 revolves, the cylinder and chamber 11
Bypass hole P3 which was open to A. P4. Communication with the cylinder chamber 11A is cut off by the rotor 24 in order from the inner bypass hole P5, and conversely, the rotor 24
The bypass holes P3' and P4' were cut off from communicating with the cylinder chamber 11B by the bypass holes P3' and P4'.

P5' opens into the cylinder chamber 11B in order from the outer bypass hole P3'.

Then, as shown in FIG. 12, when the rotor 24 revolves 180 degrees from the state shown in FIG. 6, contrary to the state shown in FIG.
The cylinder chamber JIB reaches its maximum capacity and gas suction is completed, and the bypass hole P3. P4 and P5 are all blocked from communicating with the cylinder chamber 11A by the rotor 24, and on the contrary, bypass holes P3' and P4'.

P5' are all opened to the cylinder chamber 11B.

In the course of revolution of the rotor 24 as described above.

After the discharge gas in the discharge chamber C4 has its flow rate restricted by the orifice 32, it passes through the control pressure passage C3 to the control valve 31.
and into chambers C6 and C6' of each of the bypass valves 30 and 30'.

In the control valve 3I, the chamber C in the inner cylinder 31C
Since suction pressure is introduced into the IO via boats P8 and P9, the outside of the bellows 31 is maintained at the suction pressure, and the inside of the bellows 31 is communicated with the atmosphere, so it is greatly reduced. It is maintained at atmospheric pressure.

Therefore, when the suction pressure is high, that is, when the evaporation temperature of the refrigerant gas is high and a high cooling capacity is required, the difference between the suction pressure and the atmospheric pressure becomes large.

The bellows 31K is compressed and the bushing rod 31L is moved in the direction in which it is pulled out from the communication hole 31F (to the right in the drawing). As a result, the ball 31G is biased by the spring 31J and closes the communication hole 31F, so that the discharge pressure is maintained in the chamber C8, and the bypass valve 30.
Each channel/(C6, C6') of 30' is also maintained at the discharge pressure.

In each bypass valve 30.30', chamber C7,
Since suction pressure is introduced into C7' from the suction pressure chamber C2, the discharge pressure in chambers C6 and C6' is equal to the value of the predetermined pressure device, that is, (discharge pressure)>(suction pressure)+(spring 30C) , 30C'), the spool valves 30B and 30B' are slid from the state shown in Fig. 3 or 4 in the compression direction of the springs (towards the right in the figure) against the springs 30C and 30C', and the bypass is activated. Hole P3
．． P4. P5゜P3', P4', P5' are closed in order, (discharge n force) - (suction pressure) + (spring force), ! : It stops when it becomes balanced.

Therefore, the spool valves 30B, 30B' are connected to the chamber C.
Close the bypass holes by the number corresponding to the magnitude of Il + control pressure in 8, and when the suction pressure is at the specified level (close all bypass holes P3, P4, P5, P3', P4', P5' .

Also, when the suction pressure in the control valve 31 is low.

In other words, when the evaporation temperature of the refrigerant gas is low and the cooling capacity is excessive, the differential pressure between the suction pressure and atmospheric pressure is small, so the bellows 3
1K expands due to its elasticity, the tip of the bushing rod 31L advances inside the communication hole 31F, and presses the ball 31G against the spring 31J to open the communication hole 31F.

As a result, the discharge pressure in the chamber C8 flows out to the chamber CIO through the communication hole 31F, so that the pressure in the chamber C8 decreases to near the suction pressure in the chamber C8. The chamber C8 of this control valve 31 and the control pressure passage C3
The pressure in the chambers C6, C6' of the bypass valve 30, 30' communicated through the spool valve 30B also decreases to near the suction pressure.

30B' is spring 30C, 30C' 1.1m
The plugs are biased and slid toward the plugs 30D and 30D' (leftward in FIG. 5), and are inserted into the bypass hole P3. P4. P5. P
3'.

P4' and P5' are all opened.

As mentioned above, the evaporation temperature of 9 refrigerant gas is low.

Bypass hole P3 of each bypass valve 30.30'. P4゜P
5. In a state where P3', P4', and P5' are all open, for example, when the volume of the cylinder chamber 11A is reduced from the state shown in FIG. ．． P4. Bypass valve 30 from P5
suction pressure chamber C2 through chamber C7 and pressure guiding hole P6.
fleeing to and.

Bypass hole P3. P4. As the communication between P5 and the cylinder chamber 11A is sequentially cut off, the compression ratio increases, but the compression ratio increases as the communication between bypass hole P3. P4. The compression capacity of the cylinder chamber 11A is reduced by the amount of refrigerant gas that escaped from P5, and the refrigerant capacity is reduced.

In addition, the evaporation temperature of the refrigerant gas is high, and each bypass valve 30.
30' bypass hole P3. P4. P5゜P3', P
4' and P5' are all closed, the 6th
Even if the volume of the cylinder chamber 11A decreases from the state shown in the figure, the refrigerant gas within the cylinder chamber 11A is compressed without being discharged to the suction pressure chamber C2.

It is discharged from the discharge hole P1 into the discharge chamber C4. Therefore, the compression capacity of the cylinder chamber 11A at this time becomes maximum, and the cooling capacity is increased.

When the evaporation temperature is an intermediate value between the above two cases, the bypass holes of each bypass valve 30, 30' are opened by the number corresponding to the discharge pressure as described above, and the number of bypass holes that have been opened is Correspondingly cylinder chambers A and IIB
Since the compression capacity of the compressor is determined, the compressor is operated at a capacity that corresponds to the required cooling capacity.

In addition, in the above embodiment, the number of bypass holes of each bypass valve was three, but it is not limited to this.
Needless to say, the larger the number, the more detailed control can be achieved.

Further, in the above embodiment, the present invention is applied to a compressor for a car air conditioner, but it can also be applied to other compressors, vacuum pumps, air pumps, etc.

(Effects of the Invention) As described above, according to the present invention, the capacity of the compressor is determined in stages by opening a required number of bypass holes communicating with the cylinder chamber of the compressor.

Capacity can be changed in detail according to load, resulting in high operating efficiency. In addition, since a spool valve is used to open and close the bypass hole, it is easy to manufacture and has high processing accuracy.
High reliability with little leakage.

[Brief explanation of drawings]

1 is a side sectional view taken along line II in FIG. 2 showing an embodiment of the present invention, FIG. 2 is a sectional view taken along line ■-■ in FIG. 4 is a sectional view taken along line IV--IV in FIG. 3, FIG. 5 is a circuit diagram showing the connection state of the bypass valve and control valve in the same embodiment, and FIGS. 6 to 12 13 is an explanatory view showing the compressed state of the cylinder chamber as the rotor rotates, and FIG. 13 is a sectional view showing a conventional example. 11... Cylinder 11A, IIB... Cylinder chamber 18 A... Eccentric shaft 30.30'... Bypass valve 30B, 30B'... Spool valve 30C, 3
0C'...Spring 31...Control valve 31C...Inner cylinder 3
1G...Ball 31J...Spring 31
K...Bellows 31L...Butsch rod P
3. P3', P4. P4', P5゜P5'... Bypass hole C3... Control pressure passage C6, C6'... Chamber (first chamber) C7, C
7'...Chamber (2nd chamber) C8...Chamber (3rd chamber) CIO...Chamber (4th chamber) Fig. 2 1 D1'' @7:A Fig. 9 East 8I! ! ! No.+01i1

Claims (1)

[Claims] 1. The inside of the cylinder is airtightly divided into a plurality of cylinder chambers by the rotor, and as the rotor revolves within the cylinder, the volumes of the plurality of cylinder chambers alternately increase and contract, thereby supplying compressed fluid. A discharge compressor includes a plurality of bypass holes opened in a cylinder chamber on a side whose volume is reduced as the rotor rotates, and a spool valve that opens and closes sequentially by sliding the plurality of bypass holes in the axial direction. The discharge pressure from the cylinder chamber introduced into the first chamber formed on one side of the spool valve acts on the spool valve in the direction of closing the bypass hole, and the first chamber formed on the other side acts on the spool valve in the direction of closing the bypass hole. a bypass valve in which suction pressure into the cylinder chamber introduced into the second chamber acts on the spool valve in a direction to open a bypass hole and communicate with the second chamber; and a cylinder connected to the first chamber of the bypass valve. A variable capacity compressor comprising: a control valve that reduces the discharge pressure introduced into the first chamber when the differential pressure between the suction pressure into the chamber and the atmospheric pressure is below a predetermined value. 2. The control valve has a third chamber that communicates with the first chamber of the bypass valve, a fourth chamber into which suction pressure is introduced, and a differential pressure between the suction pressure and atmospheric pressure in the fourth chamber. 2. The variable displacement compressor according to claim 1, further comprising communication means for cutting off communication between the third chamber and the fourth chamber when the value is above a predetermined value, and communicating between the third chamber and the fourth chamber when the value is below a predetermined value.