JPH0756259B2 - Variable capacity mechanism of compressor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a compressor suitable for vehicle air conditioning, and more particularly to a variable capacity mechanism of a compressor capable of changing the compression capacity according to a cooling load. .

[Prior Art] Generally, in a vehicle air-conditioning compressor, an intermittent operation of the compressor is performed by a clutch operation in order to prevent cooling failure due to excessive cooling or freezing of an evaporator. However, the intermittent operation of the compressor not only impairs the cooling feeling due to the extremely large temperature fluctuations of the cold air supplied to the passenger compartment, but also that the power source of the compressor depends on the vehicle driving engine. Due to fate, early wear of the clutch and deterioration of driving feeling were also inevitable problems.

In the invention of Japanese Patent Laid-Open No. 54-31612 focused on this point, a relief passage for bypassing a part of the refrigerant gas in the compression chambers formed in the front and rear 6 cylinders to the low pressure side is provided to change the compression capacity. A compressor adapted to do so is disclosed. That is,
As shown in FIG. 7, a relief hole d for bypassing a part of the refrigerant gas in the compression stroke of the compression chamber a to the low pressure side of the other compression chamber a, the oil reservoir chamber b, the swash plate chamber c, etc., during the suction stroke. , A lateral hole e, and a through hole f are provided, and the escape passage is opened and closed by a spool g that laterally moves in the lateral hole e, and the spool g is a bellows acting on both end surfaces thereof. It is configured to operate by the differential pressure between the sealed fluid pressure of h and the suction pressure. Therefore, when the temperature in the vehicle interior decreases, the cooling load decreases, and the suction pressure decreases, the sealing fluid pressure of the bellows h overcomes the suction pressure and activates the spool g to open the relief passage, so that the piston i has a relief hole. The compression stroke until the valve d is blocked is disabled, and the compression capacity is reduced without reducing the number of effective cylinders.

[Problems to be Solved by the Invention] However, since the bellows h described above is arranged in the central portion of the compressor in proximity to the respective bores, the sealed fluid in the bellows h depends on the discharge temperature of the compressor. Is susceptible to temperature fluctuations, and this changes the sealed fluid pressure, weakening the correlation with the cooling load and disturbing accurate control. Moreover, since the spool g operates only by the balance between the suction pressure and the sealing fluid pressure, in addition to the fluctuation of the suction pressure and the influence of the fluctuation of the sealing fluid pressure which is unrelated to this, it is easy to repeat unnecessary fine movement, There is also a problem that this causes abnormal noise.

An object of the present invention is to solve the problem of reliably operating the spool irrespective of the fluctuation of the compressor temperature and developing a variable displacement mechanism having good response to a cooling load.

[Means for Solving the Problems] In order to solve the above technical problems, the present invention provides a cylinder block in which a plurality of cylinder bores are arranged around a shaft hole penetrating the center portion, a suction chamber, and A housing having a discharge chamber for closing the opening end of the cylinder block, a drive shaft fitted and supported in the shaft hole, a swash plate for driving a piston fixed to the drive shaft, and the swash plate. A compressor having a swash plate chamber that is housed and formed separately from the suction chamber and the discharge chamber, the bypass hole communicating the shaft hole of the cylinder block with the compression chamber in each cylinder bore. And a spool which is fitted in the shaft hole to always close the bypass hole, and communicates the bypass hole with either one of the suction chamber and the swash plate chamber in response to a pressure difference between the swash plate chamber and the suction chamber. The valve means, the discharge chamber and the swash plate chamber can be communicated A structure comprising a pressure supply passage and opening / closing valve means for opening / closing the pressure supply passage according to a cooling load is adopted.

One form of the on-off valve means is a solenoid valve, which is operated by a detection command signal of a factor directly connected to a change in a cooling load such as a vehicle compartment temperature or a suction refrigerant temperature or pressure.

Another form of the on-off valve means is a spherical valve body which is built in the compressor and opens and closes the pressure supply passage, and the differential pressure of the suction chamber pressure sensitive to the fluctuation of the cooling load with respect to the resultant force of the pressure in the atmosphere chamber and the elastic force of the spring. Operated by.

[Operation] By adopting the above-described configuration, the present invention opens and closes the spool valve means for partially reducing the compression capacity of each cylinder by loading the discharge pressure through the independently existing swash plate chamber, that is, one end of the spool valve. High pressure is selectively applied to the
Moreover, the opening and closing of the pressure supply passage for loading this discharge pressure is not easily affected by the temperature of the compressor even if it is built in the solenoid valve or the compressor that operates directly by the command signal that detects the limit value of the cooling load. Since it is performed by the spherical valve element that operates by the differential pressure of the suction chamber pressure with respect to the combined force of the atmospheric chamber pressure and the spring elasticity, it does not cause unnecessary fine movement in the spool valve, and it is a compression capacity with few malfunctions that accurately correlates with the cooling load. The conversion of can be automatically revealed.

[Embodiment] A first embodiment in which the present invention is embodied in a swash plate compressor will be described below with reference to FIGS. 1 to 3.

In the figure, 1F and 1R are front and rear cylinder blocks, and a drive shaft 3 is supported via a bearing in shaft holes 2F and 2R penetrating the center of the cylinder block. It is driven to rotate by the power of the engine through the connection. A plurality of cylinder bores 4F, 4R are provided on the outer peripheral portion of the shaft holes 2F, 2R so as to surround the coaxial bores 2F, 2R, and each cylinder bore 4F, 4R is a piston driving chamber, which will be described later as a suction chamber and a discharge chamber. And swash plate chambers 5 which are formed separately from each other are provided so as to be aligned front and back, and a double-headed piston 6 is fitted in each pair of cylinder bores 4F, 4R. And each piston 6 in each cylinder bore 4F, 4R
Compression chamber 8F between the head and the valve plate described later,
8R is formed. Further, a swash plate 9 fixed to the drive shaft 3 is housed in the swash plate chamber 5 so as to be swingably rotatable.
The oscillating rotation of is transmitted as reciprocating motion to each piston 6 moored via the shoe 10 and the ball 11. 12F and 12R are front and rear housings that cover the open ends of the cylinder blocks 1F and 1R with the front and rear valve plates 7F and 7R sandwiched between them. Both housings 12F and 12R have an appropriate number of through bolts 13 Through both cylinder blocks 1F,
It is tightened together with 1R. In both housings 12F and 12R, suction chambers 14F and 14 are provided on the outer peripheral side corresponding to the cylinder bores 4F and 4R.
Discharge chambers 15F and 15R are provided concentrically on the inner peripheral side with a substantially annular partition wall therebetween. Then, suction valves 17F and 17R for opening and closing the suction ports 16F and 16R corresponding to the suction chambers 14F and 14R are provided on the inner end surfaces of both valve plates 7F and 7R, and the discharge chambers 15F and 15R are also provided on the outer end surfaces. Discharge valves 19F and 19R for opening and closing the discharge ports 18F and 18R are mounted, respectively. The suction chambers 14F and 14R are communicated with the opening 22 of the suction flange 21 through a suction passage 20 penetrating the cylinder blocks 1F and 1R and the valve plates 7F and 7R in alignment with each other, and the discharge chambers 15F and 1R.
5R similarly has the opening 25 of the discharge flange 24 through the discharge passage 23.
It is in communication with.

An expanded diameter portion is provided near each valve plate of the shaft holes 2F, 2R, and an opening formed through the valve plates 7F, 7R and a void provided in the center of both housings 12F, 12R. Pressure action chambers 26F and 26R are formed over the range. Bypass holes 27F, 2 communicating with the compression chambers 8F, 8R for the expanded diameter portion.
Evacuation holes 28F and 28R communicating with the 7R and the swash plate chamber 5 are provided,
The bypass holes 27F and 27R are opened and closed by spool valves 29F and 29R that are slidably fitted in the expanded diameter portion. The spool valves 29F and 29R are connected to the pressure acting chambers 26F and 26R through the pressure guiding holes 30F and 30R, and the pressure of the suction chambers 14F and 14R and the spring 31.
The resultant force with the elasticity of F and 31R acts in the direction of closing the bypass holes 27F and 27R, while the pressure of the swash plate chamber 5 via the relief holes 28F and 28R is in the direction of opening the bypass holes 27F and 27R. To work. Reference numeral 32 is a pressure supply passage that connects the discharge chamber 15F and the swash plate chamber 5, and 33 is an electromagnetic valve that opens and closes the pressure supply passage 32 in response to a command signal that detects a limit value of a cooling load such as a vehicle compartment temperature. In addition, 34 always indicates the pressure in the swash plate chamber 5 as the suction chamber 14
Swash plate chamber 5 and suction chamber 14R so that the pressure is controlled to be equal to the pressure inside R
It is a throttle passage communicating with and.

The operation of the variable displacement mechanism of the swash plate compressor configured as described above will be described.

When the vehicle compartment temperature is high and the cooling load exceeds the upper limit value as in the initial stage of starting the compressor, the solenoid valve 33 that opens and closes the pressure supply passage 32 is in the closed state and flows into the swash plate chamber 5. The blow-by gas that flows through the throttle passage 34 to the suction chamber 14R,
The pressure in the swash plate chamber 5 is controlled to be substantially the same as the pressure in the suction chamber 14R. Then, pressure acting chambers 26F, 26R are formed on the outer ends of the spool valves 29F, 29R fitted in the shaft holes 2F, 2R at the same pressure as the suction chambers 14F, 14R via pressure guiding holes 30F, 30R. On the other hand, the pressure of the swash plate chamber 5, which is controlled to approximately the same pressure as the pressure of the suction chamber 14R as described above, acts on the inner end side through the relief holes 28F and 28R. Valve 29F, 29R
The fluid pressures acting in both sliding directions are balanced and the spool valve 29
F and 29R are bypass holes 27F and 2 due to the elasticity of springs 31F and 31R.
It is pushed to the position where 7R is closed. That is, in this state, the compressor operates at full capacity.

After that, when the passenger compartment temperature decreases and the cooling load reaches the preset lower limit value, the solenoid valve is activated by a command signal from a sensor that detects the passenger compartment temperature or the temperature or pressure of the suction refrigerant.
33 is switched to the open state, and the pressure supply passage 32 is opened. When the pressure supply passage 32 is opened, the high-pressure refrigerant in the discharge chamber 15F is introduced into the swash plate chamber 5, and the pressure in the swash plate chamber 5 that has increased in pressure is released through the escape hole 28.
It acts on the inner ends of the spool valves 29F and 29R via F and 28R. At this time, a part of the high-pressure refrigerant introduced into the swash plate chamber 5 escapes to the suction chamber 14R via the throttle passage 34, but the escape amount is extremely small compared to the introduction amount via the pressure supply passage 32. Therefore, it does not hinder the pressurization of the swash plate chamber 4,
Also, this pressure is much higher than the combined force of the pressure action chambers 26F and 26R acting on the outer ends of the spool valves 29F and 29R and the elastic forces of the springs 31F and 31R, so that the combined force is overcome and the spool valve Steadily push 29F and 29R to open bypass holes 27F and 27R. Therefore, the refrigerant in the compression chambers 8F, 8R during the compression stroke is kept from the bypass holes 27F, 27R to the shaft holes 2F, 2R and other bypass holes 27F, 27R until the head of the piston 6 closes the bypass holes 27F, 27R. Since it flows to the swash plate chamber 5 through the compression chambers 8F and 8R during the intake stroke and the relief holes 28F and 28R, the compression work during that period is disabled, and the compression capacity is reduced without reducing the number of effective cylinders. Shift to low capacity operation.

When the cooling load gradually increases and reaches the upper limit value due to the continuation of such a low capacity operation, the electromagnetic valve 33 is switched to the closed state to close the pressure supply passage 32 by the detection command signal such as the vehicle compartment temperature. The pressure in the swash plate chamber 5 decreases due to the outflow of high-pressure cooling through the throttle passage 34, and the spool valves 29F and 29R are urged by the resultant force of the pressure in the pressure action chambers 26F and 26R and the elasticity of the springs 31F and 31R. The bypass holes 27F and 27R slide to a position where they are closed. Thus, the compressor returns to the full capacity operation again.

Next, the pressure supply passage 32 and the solenoid valve 33 for opening and closing the pressure supply passage 32 described above.
A second embodiment in which an on-off valve consisting of is built in a compressor will be described with reference to FIGS. 4 and 5.

In the figure, a pressure supply passage 32 connecting the swash plate chamber 5 and the discharge chamber 15R
Is the rear cylinder block 1R and rear valve plate 7R
Through the main passage 32a and sub-passages 32b and 32c formed in the rear housing 12R, and the sub-passages 32b and 32c are connected to each other in the lateral hole 35. , 32c are connected to and blocked from the valve seat 37 so that the spherical valve body 36 can be seated on the valve seat 37. The spherical valve element 36 is provided in the rear housing 12R.
A control mechanism 38 for controlling opening and closing is incorporated. Explaining this, a bellows 40 is accommodated in a recess 39 formed corresponding to the lateral hole 35 and opened to the outside of the machine, and a lid plate 41 to which the base end is attached has an O-ring 42. Is fitted to the inner peripheral wall of the recess 39 via the stop ring 43.
Is held in place by. A sealing plate 44 that seals the tip of the bellows 40 is inserted into the lateral hole 35 through an O-ring 45, and the spherical valve body 36 is opened in the opening direction against the elastic force of the return spring 46. An operating rod 47 for pushing the operating rod 47 is attached, and a bellows 40 is extended between the cover plate 41 and the sealing plate 44 to urge the operating rod 47 toward the spherical valve body 36 side. Is installed. Further, the lid plate 41 is formed with a through hole 50 that communicates the internal space of the bellows 40 with the outside air to form an atmospheric chamber 49, and the external space of the bellows 40 in the recess 39 is the atmospheric chamber 49. A pressure sensitive chamber 51 for expanding and contracting the bellows 40 against the pressure is formed, and the pressure sensitive chamber 51 is connected by a passage 52 to the suction chamber 14R.

Therefore, in this embodiment, when the vehicle compartment temperature is high and the cooling load is high, the temperature of the evaporator for heat exchange rises,
As the saturation pressure of the refrigerant rises and the pressure in the suction chamber 14R rises, the pressure in the pressure-sensitive chamber 51 communicating with the passage 52 also rises, which is the sum of the pressure in the atmosphere chamber 49 and the elasticity of the spring 48. Since the bellows 40 contracts, that is, the actuating rod 47 is biased in the direction to retract, the spherical valve body 36 is seated on the valve seat 37 by the return spring 46, and the communication between the sub passages 32b and 32c is cut off. The pressure supply passage 32 is closed. In this state, the blow-by gas flowing into the swash plate chamber 5 flows into the suction chamber 14F via the throttle passage 34, and the pressure in the swash plate chamber 5 is controlled to be substantially the same as the pressure in the suction chamber 14F. Then, pressure guide holes are provided on the outer ends of the spool valves 29F and 29R fitted in the shaft holes 2F and 2R.
The pressure in the pressure action chambers 26F and 26R, which are made the same pressure as the suction chambers 14F and 14R, act via 30F and 30R, while the pressure is sucked to the inner end side through the relief holes 28F and 28R as described above. Since the pressure of the swash plate chamber 5 controlled to be almost the same as the pressure of the chamber 14F acts,
The fluid pressures acting in both sliding directions of the spool valves 29F and 29R are balanced, and the spool valves 29F and 29R are pushed to the positions where the bypass holes 27F and 27R are closed by the elasticity of the springs 31F and 31R. That is, in this state, the compressor operates at full capacity.

After that, when the vehicle interior temperature decreases and the cooling load decreases, the saturation pressure decreases with the evaporator temperature, and the intake chamber 14
The pressure in the pressure sensing chamber 51 communicating with R also gradually decreases. When the cooling load reaches the set lower limit value, the spring 48 adjusted in advance for the pressure inside the pressure-sensitive chamber 51 at that time is set.
Since the resultant force of the elasticity of the pressure chamber 51 and the pressure in the atmosphere chamber 49 overcomes the pressure in the pressure sensing chamber 51, the bellows 40 is extended, that is, the operating rod 47 is urged in the forward direction, so that the spherical valve element 36 is weak. Return spring 46
The secondary passages 32b and 32c are communicated with each other by separating from the valve seat 37 against the resilience. Therefore, the pressure supply passage 32 formed by the sub passages 32b and 32c and the main passage 32a is opened, and the discharge chamber 15R
The high-pressure refrigerant inside is introduced into the swash plate chamber 5, and the pressure is increased.
Pressure acts on the spool valves 29F, 29R via the relief holes 28F, 28R and pushes the spool valves 29F, 29R in the direction to open the bypass holes 27F, 27R, resulting in a skillful reduction of the compression capacity and a low compression capacity. The shift to capacity operation is the same as in the first embodiment described above. After that, when the cooling load reaches the upper limit value due to continued low capacity operation, the bellows 40
Is contracted, and the spherical valve body 36 closes the pressure supply passage 32 accordingly, so that the process of restoring the compression capacity overlaps with the description of the first embodiment, so a detailed description thereof will be omitted.

In the case of the present embodiment, the atmospheric chamber 49 that opposes the internal pressure of the pressure sensitive chamber 51 that fluctuates depending on the suction pressure is formed in the rear housing 12R that is separated from the cylinder bore 4R, and is literally in a state of communicating with the outside air. Therefore, the influence of the fluctuation of the compressor temperature is less likely to occur, and the spherical valve element 36 operates in proper correlation with the cooling load through the change of the suction pressure.

Further, as a modified example of the present embodiment, the illustrated throttle passage 34 is abolished, and the pressure supply passage 32 is not used as a throttle passage communicating from the swash plate chamber 5 to the suction chamber 14R via the pressure sensing chamber 51 and the passage 52. The valve seat 37 of the spherical valve body 36 provided inside is formed in the opposite direction, and when the bellows 40 expands due to the reduction of the cooling load, the spherical valve body 36 is seated on the valve seat 37 and the throttle is formed. If the passage is closed, the completely closed swash plate chamber 5 is pressurized by blow-by gas, and the spool valves 29F, 29R can be operated by this pressure.

Subsequently, instead of the bypass mode in which the compression chambers 8F, 8R and the swash plate chamber 5 can communicate with each other, the compression chambers 8F, 8R are connected to the suction chamber 14
A third embodiment in which F and 14R can be communicated with each other will be described with reference to FIG.

In the drawing, the suction chamber 14 in both housings 12F and 12R
The arrangements of F, 14R and discharge chambers 15F, 15R are opposite to those of the first and second embodiments, the suction chambers 14F, 14R on the inner peripheral side and the discharge chambers on the outer peripheral side.
15F and 15R, and pressure action chambers 26F and 26R are suction chambers 14 immediately.
It is configured as F and 14R. And spool valve 29
Communication holes 53F, 53R capable of communicating the bypass holes 27F, 27R with the pressure action chambers 26F, 26R are formed in the peripheral walls of F ', 29R'.
Thus, the structures corresponding to the relief holes 28F and 28R of the first and second embodiments act only as the pressure supply holes 28F 'and 28R' for operating the spool valves 29F 'and 29R' in this embodiment. As can be seen from the figure, the springs 31F 'and 31R' are the spool valve.
It is interposed between the inner bottom surfaces of 29F 'and 29R' and the inner wall surfaces of the housings 12F and 12R.

Therefore, in this embodiment, the on-off valve opens the pressure supply passage 32,
When the spool valves 29F 'and 29R' are pushed by the high pressure load via the swash plate chamber 5 and the pressure supply holes 28F'28R ', the compression chambers 8F and 8R are connected to the bypass holes 27F and 27R. 53F, 53R
Through the pressure action chambers 26F and 26R (intake chambers 14F and 14R), a low capacity operation similar to that described above is performed.

The above description has been made on the embodiment in which the present invention is embodied in the swash plate type compressor including the cylinder bores aligned front and rear and the double-headed piston sliding in the bores. Of course, it can be applied to a swash plate compressor.

[Effects of the Invention] As described in detail above, the variable displacement mechanism of the compressor according to the present invention has the following excellent effects.

(1) The conversion of the compression capacity by opening / closing the bypass hole, particularly the conversion to a low capacity, does not depend on the delicate pressure imbalance acting on both side ends of the spool piece, and the conversion valve means provided separately can be used. High pressure is applied to one end via the plate chamber to forcibly operate the spool valve, and reliable operation can be expected without generating abnormal noise due to unnecessary fine movement of the spool valve.

(2) In particular, according to the first embodiment, the high pressure load on the spool valve is performed by switching the solenoid valve based on the detection command signal such as the vehicle interior temperature, so that the variable displacement control is accurately correlated with the cooling load. Can be realized.

(3) In particular, according to the second embodiment, since the high pressure load on the spool valve is performed by the spherical valve body and the valve control mechanism built in the housing, it is relatively inexpensive and the fluctuation of the compressor temperature is suppressed. By avoiding the influence, it is possible to realize the variable displacement control that responds accurately to the change in the suction pressure correlated with the cooling load.

(4) In particular, according to the third embodiment, since the compression chamber causes a breathing action between the compression chamber and the low-pressure suction chamber via the bypass hole, the compression efficiency is improved.

(5) Since the control based on the change of the suction pressure correlates with the cooling load as well as the rotation speed of the compressor, it responds well to sudden acceleration of the vehicle and contributes to the reduction of the engine load.

[Brief description of drawings]

FIG. 1 shows a swash plate type compressor according to the first embodiment of the present invention.
A sectional front view corresponding to a section taken along line I-I of the drawing, and FIG.
II-II sectional side view of the drawing, FIG. 3 is a III-III partial sectional view of FIG. 2, FIG. 4 is a sectional front view of a swash plate type compressor showing a second embodiment of the present invention, and FIG. Similarly, FIG. 6 is an enlarged sectional view showing the on-off valve and the control mechanism of the second embodiment, FIG. 6 is a sectional front view of a swash plate compressor showing a third embodiment of the present invention, and FIG. 7 is a conventional swash plate type. It is a cross-sectional front view of a compressor. 4F, 4R ... Cylinder bore, 5 ... Swash plate chamber, 6 ... Piston, 8F8R ... Compression chamber, 12F, 12R ... Housing, 14F, 1
4R ... Suction chamber, 15F, 15R ... Discharge chamber, 26F, 26R ... Pressure action chamber, 27F, 27R ... Bypass hole, 28F28R ... Escape hole,
29F, 29R …… Spool valve, 30F, 30R …… Pressure guide hole, 31F, 3
1R ... Spring, 32 ... Pressure passage, 33 ... Solenoid valve, 34 ... Throttle passage, 36 ... Spherical valve body, 38 ... Valve control mechanism, 40 ... Bellows, 49 ... Atmosphere chamber, 51 ...... Pressure sensitive chamber

Claims (3)

[Claims] 1. A cylinder block in which a plurality of cylinder bores are arranged around an axial hole penetrating through the center, and a housing having a suction chamber and a discharge chamber for closing the open end of the cylinder block. , A drive shaft fitted and supported in the shaft hole, a swash plate for driving a piston fixed to the drive shaft, the swash plate, and a partition formed independently of the suction chamber and the discharge chamber And a bypass hole communicating the shaft hole of the cylinder block with the compression chamber in each cylinder bore, and the compressor is fitted into the shaft hole and always has the bypass hole. Spool valve means that closes and communicates the bypass hole with either the suction chamber or the swash plate chamber in response to the pressure difference between the swash plate chamber and the income chamber, and the pressure supply that enables the discharge chamber and the swash plate chamber to communicate with each other. Passage and on-off valve hand that opens and closes the pressure supply passage according to the cooling load Variable displacement mechanism of the compressor consisting of a. 2. The variable displacement mechanism according to claim 1, wherein the on-off valve means is an electromagnetic valve which operates by a command signal which detects a limit value of a cooling load. 3. The on-off valve means comprises a spherical valve body which can be seated on a valve seat in the pressure supply passage, a pressure sensing chamber which communicates with the suction chamber via a pressure guiding passage, and a pressure sensing chamber which opposes the pressure sensing chamber. 2. The bellows according to claim 1, which is constituted by a bellows which is formed by partitioning an atmosphere chamber containing a compression spring, and an operating rod which is attached to the bellows to open and close the spherical valve body. Variable capacity mechanism.