JPS62237086A - Variable capacity compressor - Google Patents

Abstract

PURPOSE:To enable wide-range and accurate control of a varying area, by devising a measure in that a throttle valve is actuated, a flow rat of suction coolant is limited, and through utilization of a difference in a pressure between the upper stream and the downstream of the throttle valve, a bypass passage is opened, and a part of compression function is made incompetent. CONSTITUTION:First, a throttle valve means 33 is actuated in response to the pressure of a feedback coolant to control a flow rate of a coolant. Secondly, through utilization of a difference in a coolant pressure between the upper stream and the downstream of the throttle valve 33, a spool valve means 29 is actuated, and by opening a bypass passage, formed by boring a bypass hole 27, communicated with a compression chamber 8F through the large part of a shaft hole 2F, and an escape hole 28, communicated with a cam shaft chamber 5, a part of compression function related to a front cylinder bore 4F is made incompetent. Thirdly, based on a detecting instruction for a coolant load, the valve control means of a delivery valves 19F and 19R releasing mechanism is actuated, and all of compression ability related to a rear cylinder bore 4R is selectively made incompetent. Through accurate correlation with a coolant load produced resulting from combination of three compression volume reducing elements, a wide- range varying area can be controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a compressor suitable for vehicle air conditioning, and more particularly to a variable capacity compressor that can change compression capacity in accordance with cooling load.

[Prior Art] Generally, in a vehicle air conditioning compressor, intermittent operation of the compressor is performed by operating a clutch in order to solve cooling problems caused by excessive cooling or freezing of the evaporator. However, intermittent operation of the compressor not only causes extreme fluctuations in the temperature of the cold air supplied to the passenger compartment, impairing the cooling feeling, but also makes the compressor's power source dependent on the vehicle's driving engine. As fate would have it, premature clutch wear and deterioration of driving feeling were unavoidable problems.

The invention of JP-A-54-31612 focused on this point, in which a relief passage was provided to bypass a part of the refrigerant gas in the compression chamber formed in the bores of the six front and rear cylinders to the low pressure side, thereby changing the compression capacity. A compressor is disclosed.

That is, as shown in FIG. 11, part of the refrigerant gas in the compression chamber a during the compression stroke is transferred to the other compression chamber a during the suction stroke.
A relief passage consisting of a relief hole d1, a horizontal hole e, and a through hole f is provided to bypass the oil sump chamber and the swash plate chamber C to the low pressure side, and this relief passage is opened and closed by a spool 9 that moves laterally within the horizontal hole e. The spool 9 is configured to be operated by the differential pressure between the sealing fluid pressure of the bellows h and the suction pressure acting on both end surfaces of the spool 9. Therefore, when the temperature in the passenger compartment decreases, the cooling load decreases, and the suction pressure decreases, the sealing fluid pressure of the bellows h overcomes the suction pressure and operates the spool 9 to open the relief passage, so that the piston i moves into the relief hole. The compression stroke up to closing d is disabled,
Compression capacity is reduced without reducing the number of effective cylinders.

Furthermore, as seen in the invention of JP-A No. 57-73877, the discharge valve associated with one cylinder bore is floated to a non-operating state by selective loading of the same high and low pressures by switching a solenoid valve, and the compression function is activated. A variable displacement compressor that can reduce the amount by half is also known.

[Problems to be Solved by the Invention] However, since the bellows h in the former invention is arranged in the center of the compressor in close proximity to each bore, the sealing fluid within the bellows h is affected by the discharge temperature. They are susceptible to temperature fluctuations in the compressor, which changes the sealing fluid pressure, which has the disadvantage of weakening the correlation with the cooling load and disrupting accurate control. In addition, both of the above-mentioned known inventions have a narrow variable range because they are limited to two-stage control of full capacity operation and low capacity operation, and cannot perform detailed ilJ III adapted to the cooling load. It was by no means satisfactory.

The present invention aims to solve the technical problem of developing a variable displacement compressor that accurately responds to cooling load regardless of compression vA humidity and temperature fluctuations and has a wide variable range. .

[Means for Solving the Problems] In order to solve the above-mentioned technical problems, the present invention provides a suction chamber and a discharge chamber arranged to face each other in a plurality of cylinder bores that are aligned in the front and back, and a swash plate for driving a piston. a swash plate chamber that is partitioned independently from the suction chamber and discharge chamber that house the refrigerant, a suction passage that guides the return refrigerant to the suction chamber, a compression chamber in the front cylinder bore, and a swash plate chamber or suction chamber. a spool valve means that opens and closes the bypass passage based on the pressure difference between the swash plate chamber and the suction chamber; and a spool valve means that is incorporated in the suction passage and controls the flow rate of the return refrigerant according to the pressure of the return refrigerant. a pressure supply passage communicating the suction passage and the swash plate chamber in an upstream region of the throttle valve means, and a valve control means for selectively disabling the compression function related to the rear cylinder bore. The configuration is adopted.

One form of the valve control means is a discharge valve release groove that can levitate the discharge valve to a non-operating state by selectively applying high and low pressures based on a cooling load detection command, and other forms are similar. This is a suction valve opening mechanism that can be floated to a non-operating state.

[Function] By employing the above configuration, the compressor of the present invention firstly operates the throttle valve means in response to the pressure of the returned refrigerant to limit the flow of the suction refrigerant, and secondly, the throttle valve The spool valve means is actuated using the differential pressure of the refrigerant in the upstream and downstream regions of the valve means, and the bypass passage is opened to partially disable the compression function related to the front cylinder bore, and thirdly, the cooling load is detected. A wide variable range control that accurately correlates with the cooling load by combining three compression capacity reduction elements: activating the valve control means based on commands and selectively disabling all of the compression capacity related to the rear cylinder bore. It can be performed.

[Example] Hereinafter, a first example of a variable capacity compressor according to the present invention will be described.
This will be explained based on FIGS.

In the figure, 1F and 1R are front and rear cylinder blocks, and a drive shaft 3 is supported through bearings in shaft holes 2F and 2R penetrated through the center of the blocks, and the drive shaft 3 is not shown. It is driven to rotate by the power of the engine through the connection of a clutch. A plurality of cylinder bores 4F14R are provided on the outer periphery of the shaft holes 2F, 2R so as to surround the coaxial holes 2F, 2R, and each cylinder bore 4F, 4R serves as a piston drive chamber, which is different from the suction chamber and discharge chamber described later. There is an independently partitioned swash plate chamber 5 in between! 1, and a double-headed piston 6 is fitted in the multiple pairs of cylinder bores 4F14R.

In each cylinder bore 4F, 4R, there is a compression chamber 8F between the head of each piston 6 and a valve plate, which will be described later.
8R is formed. In addition, the drive shaft 3 is provided in the swash plate chamber 5.
A swash plate 9 fixed to the swash plate 9 is housed so as to be swingable and rotatable, and the swash plate 9's swing rotation is transmitted as a reciprocating motion to each moored piston 6 via shoes 10 and balls 11. 12F
, 12R are the front and rear valve plates 7F, respectively.
, 7R in between, and cover the front ends of the cylinder blocks 1F and 1R. They are fastened together. Inside both housings 12F and 12R are the above-mentioned cylinder bores 4F,
4R, suction chambers 14F, 14R on the outer circumferential side, and discharge chambers 15F, 15R on the inner circumferential side are provided concentrically with a substantially annular partition between them. Above suction chamber 14F, 1/I
R indicates suction passages 20F, 2 which are aligned and penetrate through both cylinder blocks 1F, 1R and both valve plates 7F, 7R.
communicates with the opening 22 of the suction flange 21 via the OR,
Similarly, the discharge chambers 15F and 15R are discharge passages 23F and 23R.
The opening 25 of the discharge flange 24 is communicated with the opening 25 of the discharge flange 24 through the opening 25 of the discharge flange 24.

An enlarged diameter portion is provided near the valve plate of the shaft hole 2F, and a pressure action chamber 26 extends between the opening penetrated through the valve plate 7F and the cavity provided in the center of the front housing 12F. is formed. A bypass hole 27 that communicates with the compression chamber 8F and a relief hole 28 that communicates with the swash plate chamber 5 are bored in the enlarged diameter portion to constitute a bypass passage,
The bypass passage is closed by a spool valve 29 slidably fitted within the enlarged diameter portion. The resultant force of the pressure in the suction chamber 14F communicating with the pressure action chamber 26 through the pressure guiding hole 30 and the elasticity of the spring 31 acts on the spool valve 29 in a direction to close the bypass passage, while the relief hole 28 The pressure in the swash plate chamber 5 that passes through acts in a direction to open the bypass passage.

A bottomed cylindrical storage case 32 is fitted into the boss portion 21a of the suction flange 21, and a cylindrical throttle valve 33 is slidably inserted into the through hole 21b formed at the center of the boss portion 21a. There is. A bellows 34 is connected between the base end 33a of the throttle valve 33 and the boss 21a, and a pressure chamber 35 formed between the throttle valve 33 and the bellows 34 is formed in the throttle valve 33. It communicates with the suction passage 20- in the suction flange 21 through a pressure guiding path 33b.

A spring 36 is interposed between the throttle valve 33 and the bottom surface of the storage case 32, and normally biases the throttle valve 33 in the direction of closing the valve hole 37 provided in the middle of the suction passage 20'. That's what I do. The inside of the storage case 32 in which the spring 36 is arranged is an atmosphere v38 that communicates with the outside air through a through hole 32a.

On the other hand, one end of a sweat absorption passage 39 communicating with the swash plate chamber 5 is opened in the suction passage 20' in the upstream region of the valve hole 37, and the throttle valve 33 allows the refrigerant to flow through the valve hole 37.
By restricting the refrigerant in the suction passage 20, which is maintained at a predetermined pressure, is introduced into the swash plate chamber 5.

The above valve plates 7F and 7R have suction ports 16F and 16.
R and discharge ports 18F and 18R are provided through the compression chambers 8F and 8R, and the compression chambers 8F and 8R communicate with the suction chambers 14F and 114R and the discharge chambers 15F and 15R.
Suction valve 1 for 116R and discharge ports 18F and 18R
7F, 17R and discharge valves 19F, 19R are provided. Therefore, the discharge valves 19F and 19R are connected to the presser feet 40 and 4.
1 regulates its opening degree, and is fastened to the front valve plate 7F together with the presser foot 40, but the rear valve plate 7R, together with the presser foot 41, is in a normal operating state and discharge. The outlet 18R can be moved to a non-operating state in which it floats open. That is, in this embodiment, the discharge valve 1m is used as the valve 1iIJ f11 means for selectively disabling the compression function related to the rear cylinder bore 4R.
Equipped with a release mechanism.

To further explain the mechanism, the presser foot 41 is connected to the discharge valve 19R.
almost the same shape, that is, the annular base 41a and each discharge port 18
The discharge valve 19R and the presser foot 41 are formed by a lead portion 41b extending to face the presser foot 41, and a cylindrical spool 42 concentrically abuts against the back surface of the presser foot 41. They are fastened together by bolts 43, and the spool 42 is fitted in a bottomed recess 44 defined in the center of the rear housing 12R so as to be slidable in the axial direction.

The three members fastened together are the rear housing 12R.
Rotation is prevented by a bottle 45 installed in the inner partition wall.

In addition, a cylindrical spring receiver 46 is fitted into a space 47 beyond the shaft end of the drive shaft 3 in the shaft hole 2R, and is held by the rear valve plate 7R. A spring 48 is interposed between the discharge valve 19R and the discharge valve 19R, which urges the discharge valve 19R to always be in a floating, non-operating state. The circumferential surface and bottom surface of the spring receiver 46 include its cylindrical hole and the hollow space 4.
A suitable number of small holes 46a are provided through the rear cylinder block 1R to communicate with the swash plate chamber 5, and a communication passage 49 is formed in the wall between the bores of the rear cylinder block 1R. In the non-operating state where the discharge valve 19R is held in the floating position by these cylinder holes, small holes 45a and communication passage 49, the discharge chamber 15R is communicated with the swash plate seedling 5, but when the discharge valve 19R is normally closed. In the operating state, the communication is cut off. A pressure guiding hole 50 for guiding pressure to the back surface of the spool 42 is bored in the center of the rear housing 12R, and this pressure guiding hole 50 is connected to the first electromagnetic valve 5.
It is connected to the discharge chamber 15F by a high-pressure pipe 52 including a second ffim valve 53, and connected to the suction chamber 14R by a low-pressure pipe 54 including a second ffim valve 53. Opening/closing control of the first solenoid valve 51 and the second solenoid valve 53 is performed in accordance with a cooling load detection command such as the cabin temperature or suction system pressure, and an important operation of a compressor drive clutch (not shown).

Note that 55 is a check valve disposed in a communication passage 56 connecting the discharge passage 23R and the discharge flange 24 to open and close the communication passage 56, and when the discharge valve 19R is floated and opened,
This prevents the high-pressure refrigerant that has passed through the discharge passage 23F and reached the discharge flange 24 from flowing back through the communication passage 56 and the discharge passage 23R to the discharge chamber 15R, which is in a low-pressure state.

The operation of each variable compressor set constructed as described above will be explained.

First, when the compressor is stopped, the pressure inside the machine is balanced, the throttle valve 33 is fully open, the spool valve 29 is fully open, the first solenoid valve 51 is closed, the second solenoid valve 53 is open, and the discharge valve 19R is floating open. Inactive. From this state, the clutch is turned ON.
Then, as detailed later, the rear cylinder bore 4R
The compression function related to this is completely disabled, and in the 10-cylinder compressor shown in the figure, only the front cylinder bore 4F functions effectively and is activated at a low capacity operation of 5 cylinders at 50% capacity, reducing the start-up torque. In other words, the startup shock is skillfully alleviated. Then, after a short period of time, the first solenoid valve 51 is opened and the second solenoid valve 53 is closed by a timer command based on the ON signal of the clutch.

When the cabin temperature is high and the cooling load is high, such as when the compressor starts up, the temperature of the evaporator that performs heat exchange increases, so the saturation pressure of the refrigerant increases, and the refrigerant is sucked into the suction pipe (not shown). As the pressure in the passage 20' increases, the pressure in the pressure chamber 35 increases, and as a result, the throttle valve 33 opens the suction passage 20' against the resultant force of the pressure in the atmospheric chamber 38 and the elasticity of the spring 36. The valve hole 37 is moved in a direction to open it.

Therefore, the pressure of the refrigerant in the downstream region of the valve hole 37 does not change, and the suction chambers 14F, 14R and the swash plate chamber 5 have the same pressure. The outer end side of the spool valve 29 fitted in the shaft hole 2F is connected to the suction chamber 14F through a pressure guiding hole 30.
The pressure in the pressure chamber 26 communicating with the spool valve 29 acts on the pressure chamber 26, and the pressure in the swash plate chamber 5, which has the same pressure as the suction chamber 14F, is released through the relief hole 28 on the inner end side in one direction. Both W4
The fluid pressures acting in the initial direction are balanced, and the two spool valves are pushed in the direction of closing the bypass hole 27 by the elasticity of the spring 31. When the discharge pressure acts on the back surface of the spool 42 through the high pressure pipe 52 due to the normal compression action on the front cylinder bore 4F, the discharge valve 19R resists the elasticity of the spring 48 and moves to the normal closed position, that is, the valve Pressed against the plate 7R, in order to close each discharge port 18R and cut off communication between the discharge chamber 15R and the cylinder hole, a normal compression action is also started for the rear cylinder bore 4R, and the check valve 55 closes the discharge passage 23R. The pressure of the refrigerant discharged through the refrigerant is pushed up to open the communication passage 56, and thus the compressor shifts to 100% full capacity operation. In addition,
The 50% capacity operation immediately after startup and the subsequent 100% full capacity operation explained so far are cases 1 and 2 listed in Table 1.
Applies to.

After that, when the temperature in the city air decreases and the cooling load decreases, the evaporator temperature begins to decrease and the saturation pressure also decreases. At the same time as this saturation pressure decreases, the pressure in the suction passage 20' (suction pipe line) decreases, and the pressure in the pressure chamber 35 also decreases. When the pressure in the pressure chamber 35 decreases beyond a predetermined value, the force relationship of the pressure in the pressure chamber 35 with respect to the resultant force of the internal pressure in the atmospheric chamber 38 and the elasticity of the spring 36 is reversed, and the throttle valve 33 It moves in the direction of closing the hole 37, and the opening degree of flow rate restriction by the throttle valve 33 is maintained in a state where the above-mentioned force relationship is balanced. That is, the compression capacity is appropriately reduced, and at the same time the valve hole 37
The pressure in the suction passage 20'' (suction pipe line) in the upstream region is prevented from decreasing beyond a predetermined value.

As the pressure in the pressure chamber 35 decreases, the throttle valve 33
As the flow rate restriction progresses, the amount of refrigerant introduced into the suction chamber 14F via the suction passage 20F becomes even smaller, and eventually the pressures in the suction ff14F and the pressure action chamber 26 decrease beyond a predetermined value. On the other hand, the flow rate υJilt due to the throttle valve 33
The pressure in the suction passage 20'' located upstream of the valve hole 37, where a predetermined pressure is maintained by The resultant force of the pressure in the pressure acting chamber 26 acting on the side and the elasticity of the spring 31 yields to the pressure in the swash plate chamber 5 acting on the inner end side of the spool valve 29 through the relief hole 28, and the spool valve 29 The refrigerant in the compression chamber 8F during the compression stroke flows from the bypass hole 27 to the shaft hole 2F and other places until the head of the piston 6 touches the bypass hole 27. The compression chamber 8F during the suction stroke and the above-mentioned relief hole 2
8 to the swash plate chamber 5, the compression stroke during that time is disabled, and the effective air is reduced. Shift to low capacity operation with lower compression capacity without reducing the number.

In addition, compression! If the ratio of the same volume when the head of the screw I-ne 6 closes the bypass hole 27 to the maximum volume of the 8F is set to 1/2, the compressor in this case has a capacity of 75% as shown in case 3 of Table 1. It becomes capacity operation.

Even if such 75% capacity operation continues, if the cooling load still decreases, the first solenoid valve 51 is switched to leap and the second solenoid valve 53 is switched to open based on the detection command signal of the vehicle interior temperature, etc. , low suction pressure acts on the back surface of the spool 42, and the discharge valve 19R is operated by the spring 48. As a result, the discharge port 18R is opened and the discharge chamber 15R is communicated with the swash plate chamber 5 through the cylindrical hole and the communication passage 49. Therefore, similarly to the startup described above, the compression function regarding the rear cylinder bore 4R is completely disabled. Note that at this time, the check valve 55 opens the communication passage 56 due to the pressure of the discharged refrigerant regarding the front cylinder 4F.
is closed, and the discharged refrigerant is discharged from the discharge passage 23R'! !
1.5 Prevents backflow to R.

When the compression function related to the rear cylinder bore 4R is disabled and the compression capacity further decreases, the pressure in the pressure chamber 35 increases as the pressure in the suction pipe increases, and the throttle valve 33 is displaced in the direction of increasing the opening degree. As a result, the flow restriction of the refrigerant from the suction passage 20F to the pressure action chamber 26 via the suction chamber 14' is relaxed and the pressure increases, and the resultant force of this pressure and the elasticity of the spring 31 is , overcomes the pressure in the swash plate chamber 5, slides the spool valve 29F, and closes the bypass hole 27. That is, the compression function for the front cylinder bore 4F is restored, and the compression function of the front cylinder bore 4F is restored.
Shift to % capacity operation.

If the cooling load further decreases due to the above-mentioned 50% capacity operation, the opening degree of the throttle valve 33 is reduced and the maximum flow restriction is tightened again as described above, so that the pressure difference between the refrigerant in the upstream and downstream areas is reduced. As the size increases, the spool valve 29 is pushed, and the bypass hole 27 is eventually opened again. In this way, the compressor will shift to each set of 25% capacity listed in Case 5 of Table 1, but even if the cooling load decreases further, the throttle valve 33 will reduce the temperature even further and the suction pipe will be closed. Ensure the air pressure and take measures to prevent overcooling as listed in Case 6 of Table 1.

In addition, if we add the relationship between the opening degree of the spool valve 29 and the characteristics of the spring 31 with respect to the pressure in the upstream and downstream areas of the throttle valve, which is listed for reference in Table 1, the relationship between the pressure in the upstream area of the throttle valve (swash plate chamber) and the pressure in the downstream area of the throttle valve is The spring characteristics are adjusted so that when the differential pressure (ka/am2G) with respect to the basin (suction chamber) pressure is, for example, 0.65 or less, the spool valve is fully closed, and when it is 1.1 or more, the spool valve is fully open. In addition, as in cases 2 and 3 of Table 1, the discharge valve 19R
Even if the compressor is in a normal operating state, when the clutch is turned off and the compressor is stopped, the first solenoid valve 51 is closed and the second solenoid valve 53 is opened to prepare for the next startup. .

(The following is a blank space) Table 1 Next, a second embodiment in which an intake valve opening mechanism is adopted as a valve control means for selectively disabling the compression capacity related to the LC rear cylinder bore 4R is shown in Figures 5 to 5. This will be explained based on FIG.

In the figure, the arrangement of the suction chambers 14F, 14R and the discharge chambers 151:, 151 in both housings 12F, 12R is that, contrary to the first embodiment, the inner peripheral side is the suction chamber 14F.
, 14R1 outer circumferential side is located near discharge chamber 15F, 15r,
The pressure action chamber 26 is configured as a quick suction air 14F. There are individual discharges 018 in the above discharge 'J15F and 15R.
1: Independent discharge valve 19F-, 19 facing 18R
R- and presser foot 40-141' are valve plate 7F,
It is fastened to the outer end surface of valve plate 7R, and the same valve plate 7F.
, 7R are sandwiched with integrally molded suction valves 17F', 17R' having tongue-shaped valve portions 170F, 170R and facing the respective suction ports 16F, 16R. A pushing plate 57 is fastened with bolts 43 to the tip of the spool 42 fitted into the bottomed recess 44 in the rear housing 12R, and the pushing plate 57 is attached to each suction port. It has a radial pushing piece 57a that can enter into the valve portion 16R and mechanically press and open the valve portion 170R.

As shown in FIGS. 7 and 8, the pushing piece 57a opens the suction valve 17 when the suction valve opening mechanism operates.
The valve portion 1.70 of R' is configured so that interference with the piston 6 reaching the top dead center can be absorbed by its own elastic deformation when the valve portion R is being expanded. Note that, in terms of the functionality of this embodiment, the spring receiver 46' is formed in a plate shape, and the pressure guiding hole 3o, check valve 55, and communication passage 49 are omitted, and other configurations are the same as in the first embodiment. Since there is no difference from the embodiment, detailed explanation will be omitted.

Therefore, in this embodiment, the l1dJ control mode of the solenoid valve that operates the suction valve opening mechanism is completely opposite to that of the first embodiment, and the first solenoid valve 51 opens and high discharge pressure is applied to the back surface of the spool 42. When this action is applied, the interposed moving plate 57 moves forward against the elasticity of the spring 48, and its pushing piece 57a pushes against the suction valve 17R'.
Since the suction port 16R is opened by forcibly pressing each valve portion 170R, the suction valve 17R' is kept in an inoperative state, and the compression chamber 8R is simply compressed by repeating the breathing action between it and the suction chamber 14R. The function is completely disabled.

When the first solenoid valve 51 closes and the second N solenoid valve 53 is opened, low suction pressure acts on the back of the spool 42, so the insertion plate 57 retreats together with the spool 42 due to the elasticity of the spring 48. , suction valve 17R released from forced force
' returns to normal operating condition. It is b. In addition, in this embodiment, there is no need to communicate the discharge v15R with the low pressure side, and therefore there is no backflow of the discharged refrigerant related to the front cylinder bore 4F. It has the advantage that it can be omitted.

Although the above description has been made of a configuration in which the throttle valve means is provided in the suction 7 flange 21 portion, it is also possible to adopt a configuration in which the throttle valve means is provided inside the front housing 12F, as shown in FIG. That is, the bellows 134 is attached to the inner wall of the front housing 12F, and the front end of the bellows 134 is connected to the frontage 1 of the valve plate h 7 F, which forms a part of the suction passage 20F.
A plate-like throttle valve 133 facing the 37 and capable of suppressing the rII
is attached, and the interior of the bellows 134 forms an atmospheric chamber 138 that communicates with the outside air through a through hole 132a, and the opening 137 is always closed and the throttle valve 1 is
A spring 136 is interposed to bias 33. In this example, the suction passage 20F located upstream of the throttle valve 133
It is different from the above-mentioned embodiment in that it directly communicates with the swash plate chamber 5 and the intraocular pressure passage 39 is eliminated, but there is no substantial difference in the function of the throttle valve means from the same embodiment, so a detailed explanation will be given. Explanation will be omitted.

Next, a third embodiment is provided in which a bypass passage that allows communication between the compression chamber 8F and the suction chamber 14F is used instead of the bypass passage that allows communication between the compression chamber 8F and the swash plate chamber 5 in the first and second embodiments. An example will be explained based on FIG.

In the figure, the suction chamber 1 in the front housing 12F
The arrangement of the 4F and the discharge chamber 15 is the same as in the second embodiment, with the suction chamber 14F on the inner circumference side and the discharge chamber 15F on the outer circumference side.
The pressure-acting seedling 26 is configured as an immediate suction chamber 14F. The bypass hole 2 is provided in the peripheral wall of the spool valve 29-.
7 and the pressure action chamber 26 are bored, so that the structure corresponding to the relief hole 28 in the first embodiment is the pressure supply hole 2 that operates the spool valve 29- in this embodiment.
8- Only the closure is working. As can be seen from the figure, the spring 31' is interposed between the inner bottom surface of the spool valve 29' and the inner wall surface of the housing 12F.

Therefore, in this embodiment, the suction chamber 14F and the pressure action chamber 26
When the pressure in the compression chamber 8F drops beyond a predetermined value and the spool valve 29' is moved due to the differential pressure with the pressure in the swash plate chamber 5,
A breathing action is produced between the pressure chamber 26 (suction chamber 14F) and the pressure action chamber 26 (suction chamber 14F) through the continuous hole 58 that coincides with the bypass hole 27, and the operation shifts to a low capacity operation similar to that described above.

[Effects of the Invention] As detailed above, the variable displacement compressor according to the present invention has the following features:
It produces the following excellent effects.

(1) Throttle valve means for introducing suction refrigerant into the suction chamber, spool valve means for opening and closing the bypass passage to disable part of the compression stroke for the front cylinder bore, and By cooperating with a valve control means that selectively disables the compression function, the variable range of the compression capacity can be greatly expanded.

(2) Since the throttle valve means and spool valve means are actuated by changes in suction pressure itself, variable capacity control can be performed that accurately correlates with the cold load without being affected by temperature fluctuations of the compressor. .

(3) The throttle valve means opens and closes the spool valve means.
Since ll will also be appointed, the l of the structure! J′a can be achieved.

(4) Control based on changes in suction pressure is correlated with the rotation speed of the compressor as well as the cooling load, so it responds well to sudden acceleration of the vehicle and contributes to reducing the engine load.

(5) When the compressor is started, the discharge valve or suction valve opening tI1m mechanism is opened and the compression function related to the rear cylinder bore is disabled, so that the start-up shock can be sufficiently alleviated.

(6) Particularly, according to the third embodiment, during low capacity operation, the compression chamber creates a breathing action between the compression chamber and the lower pressure suction chamber via the bypass passage, so that compression efficiency is improved.

[Brief explanation of drawings]

FIG. 1 is a sectional front view of a variable capacity compressor showing a first embodiment of the present invention, corresponding to the knee I line section in FIG. FIG. 2 is a cross-sectional side view taken along the line ff-ff in FIG. 1, and FIG. 3 is a side view of I[
[-111 line partial sectional view, FIG. 4 is IV-T in FIG.
5 is a cross-sectional front view of a variable capacity compressor showing a second embodiment of the present invention, corresponding to the v-v line section in FIG. 6; FIG. 6 is a partial sectional view taken along line Vl- Vl line cross-sectional side view, No. 7
8 is a partial sectional view showing details of the operation of the suction valve opening mechanism, and FIG. 9 is a partial sectional view showing a modification of the throttle valve means.
FIG. 10G is a cross-sectional front view of a variable displacement compressor according to a third embodiment of the present invention, and FIG. 11 is a cross-sectional front view of a conventional variable displacement compressor. 4F14R... Cylinder bore 5... Swash plate chamber 6... Screw 1-8F,
8R...Compression chambers 12F, 12R...Housing 14F, 14R...Suction chambers 15F, 15R...Discharge chambers 17F, 17R...Suction valves 19F, 19R...Discharge valves 20F, 2OR, 20 - Suction passage 21 Suction 7 lunge 23F, 23R Discharge passage 26 Pressure action chamber 27 Bypass hole 28 Relief hole 29 Spool valve 30 - Pressure guiding hole 31... Spring 33.133... Throttle valve 34.134... Bellows 35... Pressure chamber 36.136... Spring 37
... Valve hole 38.138 ... Atmospheric air 39.
...Pressure passage 42...Spool 46...Spring receiver 48...Spring 49...Communication passage 5
1...First solenoid valve 53...Second solenoid valve 55...
・Check valve 57...push plate

Claims (3)

[Claims] (1) A double-headed piston that slides in a plurality of pairs of cylinder bores that are aligned in the front and rear, a suction chamber and a discharge chamber that are arranged to face the front and rear cylinder bores, respectively, and a swash plate for driving the piston are accommodated. A swash plate chamber that is partitioned independently from the suction chamber and discharge chamber, a suction passage that guides the return refrigerant to the suction chamber, and a compression chamber in the front cylinder bore can communicate with the swash plate chamber or the suction chamber. spool valve means that opens and closes the bypass passage based on the pressure difference between the swash plate chamber and the suction chamber; and a throttle valve means that is incorporated in the suction passage and controls the flow rate of the return refrigerant according to the pressure of the return refrigerant. a variable displacement compressor comprising: a suction passage communicating the suction passage in an upstream region of the throttle valve means with the swash plate chamber; and a valve control means for selectively disabling the compression function related to the rear cylinder bore. . (2) The valve control means is a discharge valve opening mechanism that can levitate the discharge valve to a non-operating state by selectively applying both high and low pressure based on a cooling load detection command. compressor. (3) The valve control means is a suction valve opening mechanism that can levitate the suction valve to a non-operating state by selectively applying both high and low pressure based on a cooling load detection command. compressor.