JP2001165076A - Variable displacement gas compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a variable displacement gas compressor capable of controlling the optimum refrigerant sealing capacity without making the equipment complex and increasing the cost. SOLUTION: A driving shaft 12 is made of a material having a coefficient of thermal expansion higher than that of a material of a sleeve 14 for making a driving shaft gap G variable on the basis of the difference in the coefficient of thermal expansion between the driving shaft 12 and the sleeve 14. For example, when refrigerant discharging capacity of a compressor is increased, the driving shaft gap G is reduced on the basis of the difference in the coefficients of thermal expansion between the driving shaft 12 and the sleeve 14, an oil feeding-out amount from a control pressure chamber 17 to an intake chamber 7 side through the driving shaft gap G is reduced, and the control pressure Pc of the control pressure chamber 17 is increased in a short time. Thereby, the driving shaft 12 slides in the MAX moving direction, a control plate 9 turns counterclockwise interlocking with this sliding so as to enlarge containment capacity of a refrigerant, and refrigerant discharge is increased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable displacement gas compressor used in a car air conditioner system and the like, and more particularly, to a more optimal control of a refrigerant discharge capacity without complicating equipment and increasing costs. It was done.

[0002]

2. Description of the Related Art FIG. 2 is a sectional view showing an example of a conventional variable displacement gas compressor (hereinafter also referred to as "compressor"). The compressor shown in FIG. 2 includes a cylinder 2 having a substantially elliptical inner circumference in a casing 1 having an open end, and a cylindrical rotor 3 is rotatably mounted in the cylinder 2.

As shown in FIG. 3, a plurality of vanes 4, 4... Are provided so as to be able to protrude and retract from the outer peripheral surface of the rotor 3 toward the inner surface of the cylinder 2. Between them, a crescent-shaped cylinder inner space 5 is formed due to the relationship between the two shapes, and the cylinder inner space 5 is partitioned into a plurality of small chambers by vanes 4, 4,. Each of the partitioned small chambers is a compression chamber 6, 6,..., And the compression chamber 6 repeatedly changes in volume due to the rotation of the rotor 3, and the refrigerant (low-pressure refrigerant gas) flows from the intake chamber 7 side due to the volume change. After confining and compressing the compressed air, the compressed refrigerant (high-pressure refrigerant gas) is discharged to the discharge chamber 8 side.

In the variable displacement gas compressor shown in FIG. 2, the capacity of the refrigerant confined in the compression chamber 6 (hereinafter, referred to as "refrigerant confinement capacity") is changed as described above to thereby discharge the discharge chamber 7. The cooling capacity is adjusted by changing the capacity of the compressed refrigerant discharged to the side (hereinafter referred to as the “refrigerant discharge capacity”). A means for increasing or decreasing the refrigerant confinement capacity is the control plate 9 ( (See FIG. 4),
The control plate 9 is rotatably mounted between the compression chamber 6 and the intake chamber 7.

The operation of the control plate 9 will be described with reference to FIG. 5. When the control plate 9 rotates clockwise (clockwise) to the maximum, the refrigerant confinement capacity becomes minimum (MIN). This is because, while the compression chamber 6 starts to shift from the maximum volume to the minimum volume, a part of the refrigerant once sucked into the compression chamber 6 is removed through the cutout 10 on the outer periphery of the control plate 9. This is because they are returned to the side.

On the other hand, when the control plate 9 rotates clockwise (counterclockwise) from the position where the control plate 9 rotates clockwise to the maximum as described above, the intake air passes through the notch 10 on the outer periphery of the control plate 9 as described above. The amount of refrigerant discharged and returned to the chamber 7 decreases, and as a result, the refrigerant confinement capacity increases. And
When the control plate 9 rotates counterclockwise to the maximum, the refrigerant confinement capacity reaches the maximum (MAX).

[0007] The rotational movement of the control plate 9 as described above is performed by a control plate driving mechanism. That is, the control plate 9 is connected to the drive shaft 12 via the drive pin 11, and the drive shaft 12 is disposed so as to be able to slide back and forth in a sleeve 14 formed inside the front head 1a. . Then, the drive shaft 12 is
When the control plate 9 is slid inside, the linear movement of the drive shaft 12 is converted into the rotational movement of the control plate 9 by the drive pin 11, and the control plate 9 rotates. For example, when the drive shaft 12 slides in the direction indicated by the arrow A in FIG. 5, the control plate 9 rotates counterclockwise in conjunction with this, and as a result, the refrigerant confinement capacity increases. When the drive shaft 12 slides in the direction indicated by the arrow C in FIG.
In conjunction with this, the control plate 9 rotates clockwise, and the refrigerant confinement capacity decreases.

In the following description, the direction in which the drive shaft 12 slides toward the side where the refrigerant confinement capacity increases as described above (the direction indicated by the arrow A in the figure) is referred to as the “MAX transition direction”, and the refrigerant confinement capacity The direction in which the drive shaft 12 slides toward the side where the value decreases (the direction indicated by the arrow C in the figure) is referred to as the “MIN transition direction”. Therefore, when the drive shaft 12 slides in the MAX transition direction, the refrigerant confinement capacity increases, while
When the drive shaft 12 slides in the MIN transition direction, the refrigerant confinement capacity decreases.

The direction in which the drive shaft 12 slides in the MAX transition direction or the MIN transition direction is determined by the force applied to the drive shaft 12. That is, the suction pressure Ps of the refrigerant in the suction chamber 7 and the spring force Fs of the compression spring 21 are applied to one end surface 12a of the drive shaft 12, while the control pressure chamber 1 is applied to the other end surface 12b of the drive shaft 12.
The control pressure Pc in 7 is applied. Among them, the suction pressure Ps and the spring force Fs act so as to be directed in the same direction as the MIN shift direction of the drive shaft 12. The control pressure Pc is controlled by the oil on which the refrigerant discharge pressure Pd acts, that is, the discharge chamber 8.
It is formed by squeezing the oil in an oil sump 19 stored at the bottom by the control valve 13, and
No. 2 acts in the same direction as the MAX transition direction.

Incidentally, when the refrigerant discharge capacity of the compressor is increased, the valve opening of the control valve 13 may be increased.
Then, the amount of oil flowing into the control pressure chamber 17 from the control valve 13 increases, and the control pressure Pc increases.
Force to slide in the MAX transition direction increases,
The drive shaft 12 moves in the MAX transition direction. In conjunction with this, the control plate 9 rotates counterclockwise, and the refrigerant confinement capacity increases.

A gap G (hereinafter referred to as "drive shaft clearance") is provided between the drive shaft 12 and the sleeve 14, and the oil in the control pressure chamber 17 passes through the drive shaft clearance G. It can flow out to the intake chamber 7 side.

Accordingly, the control pressure Pc in the control pressure chamber 17 is equal to the difference between the oil inflow from the control valve 13 to the control pressure chamber 17 and the oil outflow from the control pressure chamber 17 via the drive shaft clearance G. Is determined by

Considering a case where this kind of compressor is mounted on a vehicle as a part of a car air conditioner system, if the engine speed of the vehicle suddenly decreases,
The drive shaft clearance G may be reduced. This is because when the engine rotation speed of the vehicle suddenly decreases, the refrigerant discharge capacity of the compressor decreases and the cooling capacity decreases accordingly, so the refrigerant discharge capacity of the compressor increases to keep the cooling capacity constant. It is necessary to increase the control pressure Pc by increasing the amount of oil flowing into the control pressure chamber 17 and reducing the amount of oil flowing out of the control pressure chamber 17 via the drive shaft clearance G. . However, since the opening area of the control valve 13 is restricted by the valve mechanism, the control pressure Pc is increased by reducing the drive shaft clearance G.

On the other hand, when the engine rotational speed of the vehicle is rapidly increased, the opening area of the control valve 13 may be set to the minimum "0" and the drive shaft clearance G may be increased. this is,
When the engine speed of the vehicle suddenly increases, the cooling capacity becomes too large contrary to the case of the decrease.
It is necessary to sharply reduce the control pressure Pc of the control pressure chamber 17. In this case, when the opening area of the control valve 13 is set to “0”, only the oil outflow amount from the control pressure chamber 17 via the drive shaft clearance G becomes This is because it contributes to a decrease in the control pressure Pc.

However, when the drive shaft clearance G is made variable as described above, a new mechanism for changing the drive shaft clearance is required, which complicates the mechanism, lowers the reliability and increases the cost. There is a problem.

In consideration of both the case where the engine speed of the vehicle rapidly increases and the case where the engine speed decreases, as described above,
When the compromise between the drive shaft clearances G is set in such two situations, the control pressure chamber 17 is increased despite the case where the control pressure Pc is increased to increase the refrigerant discharge capacity.
A large amount of oil flows out through the drive shaft clearance G, so that it is difficult to increase the control pressure Pc, it takes time to obtain the maximum refrigerant confinement capacity, and the control pressure Pc is reduced to confine the refrigerant. Despite the case where it is desired to reduce the capacity, it is difficult for the oil in the control pressure chamber 17 to flow through the drive shaft clearance G, to reduce the control pressure Pc, and to obtain the minimum refrigerant confinement capacity. However, under the above two conditions, it is impossible to control the optimum refrigerant confinement capacity that can restore the increase or decrease in the cooling capacity.

[0017]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide a more optimal device without complicating the equipment and increasing the cost. An object of the present invention is to provide a variable displacement gas compressor capable of controlling the refrigerant confinement capacity, that is, controlling the refrigerant confinement capacity appropriately in response to an increase or decrease in the cooling capacity of the compressor.

[0018]

In order to achieve the above-mentioned object, the present invention is directed to a method of repeatedly changing the size of a volume, sucking a refrigerant from an intake chamber side by the volume change, confining the refrigerant, and compressing the refrigerant. A compression chamber that discharges the compressed refrigerant, a control plate that is rotatably provided between the compression chamber and the intake chamber, and that increases or decreases the refrigerant confinement capacity of the compression chamber by adjusting the rotation angle thereof; A control plate drive mechanism for rotating the control plate by sliding a drive shaft, wherein the drive shaft is provided such that one end surface thereof is exposed to the intake chamber and the other end surface faces the control pressure chamber. In the variable displacement gas compressor having a structure that slides by a force relationship among a suction pressure of a refrigerant in a chamber, a spring force, and a control pressure in the control pressure chamber, A gap is provided between the shaft and a sleeve that slidably accommodates the shaft so as to allow oil to flow out to form a control pressure applied to the drive shaft, and the entire drive shaft or the drive shaft that forms the gap Is characterized in that only the gap forming portion is made of a material having a higher coefficient of thermal expansion than the constituent material of the sleeve.

The present invention is characterized in that the entirety of the drive shaft or only the gap forming portion of the drive shaft forming the gap is made of a plastic material, and the sleeve is made of an iron material.

In the present invention, the temperature of the drive shaft and the sleeve changes due to the change in the temperature of the refrigerant sucked in the intake chamber, and the gap between the drive shaft and the sleeve (drive) varies due to the difference in the coefficient of thermal expansion between the drive shaft and the sleeve. The shaft clearance) changes so that the change in the drive shaft clearance makes it possible to appropriately adjust the refrigerant confinement capacity with respect to fluctuations in the cooling capacity of the compressor.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a variable displacement gas compressor according to the present invention will be described in detail with reference to FIG.

When the basic structure of the compressor is described with reference to FIGS. 2 and 3, for example, a compression chamber 6 and a control plate 9 are provided inside the apparatus. In addition to repeating the change in the volume, the change in the volume causes the refrigerant to be sucked in from the intake chamber 7 side, confined and compressed, and then the compressed refrigerant is discharged. It is provided so as to be rotatable between the chamber 6 and the intake chamber 7, and is configured to increase or decrease the refrigerant confinement capacity of the compression chamber 6 by adjusting the rotation angle. This is performed by the drive mechanism, that is, when the drive shaft 12 slides back and forth, the control plate 9 rotates left and right in conjunction with this, and the refrigerant confinement capacity increases and decreases, and Since the slide of the drive shaft 12 is based on the force relationship between the refrigerant suction pressure Ps, the spring force Fs, and the control pressure Pc as in the conventional case, the same members as those are denoted by the same reference numerals. Detailed description is omitted.

In the compressor of the present embodiment shown in FIG. 1, an intake chamber 7 is provided inside the front head 1a (see FIG. 2), and a sleeve 14 is formed in the intake chamber 7, and the sleeve 14 is formed. Inside, a drive shaft 12 is slidably disposed back and forth. The drive shaft 12 and the sleeve 14
A drive shaft clearance G is provided between the sleeve 14 and the sleeve 14. In order to make the drive shaft clearance G variable, the entire drive shaft 12 is formed of a material having a higher coefficient of thermal expansion than the material of the sleeve 14. .

In other words, in the compressor of the present embodiment, the constituent materials of the drive shaft 12 and the sleeve 14 are different, and the difference between the thermal expansion coefficients of the drive shaft 12 and the sleeve 14 based on the difference in the constituent materials causes the drive shaft clearance G to be reduced. It employs a mechanism that changes in size. In short, the drive shaft clearance G is variable, but the variable mechanism is not mechanical, but is due to the difference in the thermal expansion coefficient between the drive shaft 12 and the sleeve 14 due to the physical properties of the material.

The one end face 12a of the drive shaft 12 (the side to which the suction pressure Ps of the refrigerant and the spring force Fs of the compression spring 21 are applied) protrudes from the open end of the sleeve 14 and is exposed in the intake chamber 7. The other end surface 12b of the drive shaft 12
(The side to which the control pressure Pc is applied) is the control pressure chamber 1
7 are provided.

The temperature of the drive shaft 12 is greatly affected by the temperature of the refrigerant (hereinafter referred to as "intake refrigerant") which is guided from the evaporator side of the air conditioner system (not shown) into the intake chamber 7 of the compressor and is full. This is because the sleeve 14 for accommodating the drive shaft 12 itself is in the intake chamber 7 as described above, and the drive shaft one end surface 12a side is exposed in the intake chamber 7. Therefore, when the temperature of the suction refrigerant in the intake chamber 7 increases, the temperature of the drive shaft 12 and the sleeve 14 also increases, and conversely, when the temperature of the suction refrigerant in the intake chamber 7 decreases, the drive Axis 12
Also, the temperature of the sleeve 14 decreases.

Here, since the thermal expansion of the drive shaft 12 and the sleeve 14 is larger in the drive shaft 12, when the temperature of the suction refrigerant becomes higher, the drive shaft 12 thermally expands more than the sleeve 14. The drive shaft clearance G becomes smaller, so that the amount of oil flowing out from the control pressure chamber 17 to the intake chamber 7 via the drive shaft clearance G decreases, and the control pressure chamber 1
The state in which the control pressure Pc in 7 tends to increase is brought about. Conversely, when the temperature of the suction refrigerant decreases, the drive shaft 12 contracts more than the sleeve 14, so that the drive shaft clearance G increases, and therefore the oil from the control pressure chamber 17 via the drive shaft clearance G The outflow amount increases, and the control pressure Pc in the control pressure chamber 17 tends to decrease.

Next, the operation when the compressor of the present embodiment configured as described above is mounted on a vehicle as a part of a car air conditioner system will be described with reference to FIG.

In the compressor of the present embodiment, for example, if the engine speed of the vehicle suddenly decreases,
As a result, the refrigerant discharge capacity of the compressor is reduced and the cooling capacity is reduced, so it is desired to increase the refrigerant discharge capacity of the compressor. When it is desired to increase the refrigerant discharge capacity in this way, when the cooling capacity is insufficient and cooling cannot be performed, that is, when the temperature of the air ejected from the evaporator of the air conditioning system is the highest,
At this time, the temperature of the suction refrigerant in the suction chamber 7 increases. Therefore, the difference between the thermal expansion coefficients of the drive shaft 12 and the sleeve 14 causes the drive shaft 12 to thermally expand more than the sleeve 14, so that the gap between the drive shaft 12 and the sleeve 14 is reduced. That is, as shown in FIG.
Becomes smaller. Therefore, the amount of oil flowing out from the control pressure chamber 17 to the intake chamber 7 via the drive shaft clearance G decreases, and the control pressure Pc of the control pressure chamber 17 increases in a short time. As a result, the drive shaft 12 slides in the MAX transition direction (the direction of the arrow A in the figure), and in conjunction with this, the control plate 9 rotates counterclockwise, thereby increasing the refrigerant confinement capacity. Therefore, in this case, the refrigerant discharge capacity increases, the cooling capacity of the compressor increases, and the compressor can be cooled well early.

Contrary to the case described above, when it is desired to reduce the refrigerant discharge capacity of the compressor, that is, when the cooling capacity is excessive and the temperature is too low, the temperature of the refrigerant sucked in the intake chamber 7 decreases.
Due to the difference in the coefficient of thermal expansion between the drive shaft 12 and the sleeve 14, FIG.
As shown in (b), since the drive shaft 12 contracts more than the sleeve 14, the drive shaft clearance G increases. Therefore, the amount of oil flowing out from the control pressure chamber 17 to the intake chamber via the drive shaft clearance G increases, and the control pressure chamber 17
Control pressure Pc decreases. As a result, the drive shaft 12 is pushed back in the MIN transition direction (the direction of arrow C in the figure) by the total force of the spring force Fs and the suction pressure Ps, and in conjunction with this, the control plate 9 rotates clockwise, and the refrigerant The confinement capacity is reduced. Therefore, in this case, the refrigerant discharge capacity is reduced, the cooling capacity of the compressor is reduced, and excessive cooling can be avoided at an early stage.

As is apparent from the above description, in the compressor of the present embodiment, the entire drive shaft 12 is
Is made of a material having a higher coefficient of thermal expansion than that of the above material. Therefore, the drive shaft clearance G between the drive shaft 12 and the sleeve 14 can be increased or decreased only by the physical property of the material, that is, the difference in the coefficient of thermal expansion between the drive shaft 12 and the sleeve 14 without using any mechanical mechanism. Can be changed, and by the change of the drive shaft clearance G,
Appropriate adjustment of the refrigerant confinement capacity can be performed in response to fluctuations in the cooling capacity of the compressor, without complicating the equipment and reducing its reliability and cost.
More optimal control of the refrigerant confinement capacity can be achieved.

In the above embodiment, the entire drive shaft 12 is formed of a material having a higher coefficient of thermal expansion than the sleeve 14. However, the drive shaft 12 is not part of the entire drive shaft, specifically, a drive shaft clearance G. Only the gap forming portion 12c of the drive shaft 12 forming the drive shaft 12, specifically, the outer peripheral portion of the drive shaft may be formed of a material having a higher coefficient of thermal expansion than the material of the sleeve 14; Due to the difference in the thermal expansion coefficient between the gap forming portion 12c of the shaft 12 and the sleeve 14, the drive shaft clearance G
Changes in magnitude, the same effect as in the above embodiment can be obtained.

Various combinations of materials having different coefficients of thermal expansion are conceivable. For example, a combination of a plastic and an iron material may be employed. In this case, the entire drive shaft 12 or the drive shaft clearance G is formed. The gap forming portion 12c of the drive shaft 12 is formed of a plastic material,
If the sleeve 14 is formed of an iron material, the effects of the above-described embodiment can be obtained due to the difference in the coefficient of thermal expansion.

[0034]

According to the present invention, as described above, only the gap forming portion of the drive shaft, which forms the gap (drive shaft clearance) between the drive shaft and the sleeve, constitutes the sleeve. It is made of a material having a higher coefficient of thermal expansion than the material. Therefore, without using any mechanical mechanism, the drive shaft clearance can be changed in size only by the physical property of the material, that is, the difference in the coefficient of thermal expansion between the drive shaft and the sleeve. Due to the change in the shaft clearance, it is possible to quickly adjust the refrigerant confinement capacity appropriately in response to fluctuations in the cooling capacity of the compressor, resulting in equipment complexity, resulting in reduced reliability and increased costs. Thus, it is possible to provide a variable displacement gas compressor that can control the refrigerant confinement capacity more optimally.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a control mechanism of a refrigerant confinement capacity which is a main part of the present invention. FIG. 1 (a) shows a state in which a drive shaft clearance is reduced due to a difference in thermal expansion coefficient. FIG. 2B shows a state in which the drive shaft clearance becomes small due to the difference in the coefficient of thermal expansion.

FIG. 2 is a sectional view of a conventional variable displacement gas compressor.

FIG. 3 is a sectional view taken along line AA of FIG. 2;

FIG. 4 is a sectional view taken along line BB of FIG. 2;

FIG. 5 is an explanatory diagram of a control mechanism of a refrigerant confinement capacity in the conventional variable displacement gas compressor shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Casing 1a Front head 2 Cylinder 3 Rotor 4 Vane 5 Crescent shaped cylinder inner space 6 Compression chamber 7 Intake chamber 8 Discharge chamber 9 Control plate 10 Notch on control plate outer periphery 11 Drive pin 12 Drive shaft 12a Drive shaft end surface 12b Drive shaft other end surface 12c Drive shaft gap forming portion 13 Control valve 14 Sleeve 17 Control pressure chamber 19 Oil reservoir 21 Compression spring Pc Control pressure Pd Discharge pressure Ps Suction pressure Fs Spring force

Claims (2)

[Claims] 1. By repeating a change in volume,
After sucking the refrigerant from the intake chamber side, confining and compressing the refrigerant, a compression chamber that discharges the compressed refrigerant, and a rotatably provided between the compression chamber and the intake chamber, the rotation angle of which is adjusted. A control plate for increasing or decreasing the refrigerant confinement capacity of the compression chamber; and a control plate drive mechanism for rotating the control plate by sliding a drive shaft, wherein the drive shaft has one end surface exposed to the intake chamber, The other end face is provided so as to face the control pressure chamber, and the variable displacement gas compressor has a structure in which the end face slides according to the force relationship between the suction pressure of the refrigerant in the suction chamber, the spring force, and the control pressure in the control pressure chamber. In the above, a gap for oil outflow forming a control pressure applied to the drive shaft is provided between the drive shaft and a sleeve for slidably storing the drive shaft. The variable displacement gas compressor, wherein the entire drive shaft or only the gap forming portion of the drive shaft forming the gap is made of a material having a higher coefficient of thermal expansion than the material of the sleeve. 2. The variable capacitor according to claim 1, wherein the entirety of the drive shaft or only a gap forming portion of the drive shaft forming the gap is made of a plastic material, and the sleeve is made of an iron material. Type gas compressor.