JP3717731B2 - Variable capacity gas compressor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a variable capacity gas compressor used in a car air conditioner system and the like, and more particularly enables control of a more optimal refrigerant discharge capacity without incurring complexity and cost increase.
[0002]
[Prior art]
FIG. 2 is a sectional view showing an example of a conventional variable capacity gas compressor (hereinafter also abbreviated as “compressor”). The compressor shown in FIG. 2 has a cylinder 2 having a substantially elliptical inner periphery in a one-end opening type casing 1, and a columnar rotor 3 is rotatably mounted in the cylinder 2.
[0003]
As shown in FIG. 3, a plurality of vanes 4, 4,... Are provided from the outer peripheral surface of the rotor 3 toward the inner surface of the cylinder 2. A crescent-shaped cylinder inner space 5 is formed from the relationship between the two shapes, and the cylinder inner space 5 is divided 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 repeats the change in volume by the rotation of the rotor 3, and the refrigerant (low-pressure refrigerant gas) from the intake chamber 7 side by the volume change. Then, after confining and compressing, the compressed refrigerant (high-pressure refrigerant gas) is discharged to the discharge chamber 8 side.
[0004]
In the variable capacity gas compressor shown in FIG. 2, the refrigerant is discharged to the discharge chamber 7 side by changing the capacity of the refrigerant confined in the compression chamber 6 (hereinafter referred to as “refrigerant confinement capacity”). The cooling capacity is adjusted by changing the capacity of the compressed refrigerant (hereinafter referred to as “refrigerant discharge capacity”), but the 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.
[0005]
The operation of the control plate 9 will be described with reference to FIG. 5. When the control plate 9 rotates to the maximum clockwise (clockwise), the refrigerant confinement capacity becomes the minimum (MIN). This is because part of the refrigerant once sucked into the compression chamber 6 passes through the notch 10 on the outer periphery of the control plate 9 while the compression chamber 6 starts to shift from the maximum volume to the minimum volume. It is because it is discharged back to the side.
[0006]
On the other hand, when the control plate 9 is rotated counterclockwise (counterclockwise) from the position where the control plate 9 is rotated to the maximum clockwise as described above, the intake chamber 7 side through the notch 10 on the outer periphery of the control plate 9 as described above. As a result, the amount of refrigerant discharged to the refrigerant decreases, and as a result, the refrigerant confinement capacity increases. Then, when the control plate 9 rotates counterclockwise to the maximum, the refrigerant confinement capacity becomes 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 arranged so that it can slide back and forth within a sleeve 14 formed inside the front head 1a. . When the drive shaft 12 slides in the sleeve 14, the linear slide motion of the drive shaft 12 is converted into the rotational motion of the control plate 9 by the drive pins 11, and the control plate 9 rotates. For example, when the drive shaft 12 slides in the direction indicated by arrow A in FIG. 5, the control plate 9 rotates counterclockwise in conjunction with this, and as a result, the refrigerant confinement capacity increases. Further, when the drive shaft 12 slides in the direction indicated by the arrow C in FIG. 5, the control plate 9 rotates clockwise in conjunction with this, and the refrigerant confinement capacity decreases.
[0008]
In the following description, the sliding direction of the drive shaft 12 toward the side where the refrigerant confinement capacity increases as described above (the direction indicated by arrow A in the figure) is referred to as “MAX transition direction”, and the refrigerant confinement capacity decreases. The sliding direction of the drive shaft 12 to the side (the direction indicated by the arrow C in the figure) is referred to as “MIN transition direction”. Therefore, when the drive shaft 12 slides in the MAX transition direction, the refrigerant confinement capacity increases. On the other hand, when the drive shaft 12 slides in the MIN transition direction, the refrigerant confinement capacity decreases.
[0009]
By the way, whether the drive shaft 12 slides in the MAX transition direction or the MIN transition direction is determined by a relationship of forces applied to the drive shaft 12. That is, the refrigerant suction pressure Ps in the intake chamber 7 and the spring force Fs of the compression spring 21 are applied to the one end surface 12 a of the drive shaft 12, while the other end surface 12 b of the drive shaft 12 is in the control pressure chamber 17. The control pressure Pc is applied. Among these, the suction pressure Ps and the spring force Fs act so as to face the same direction as the MIN transition direction of the drive shaft 12. The control pressure Pc is formed by squeezing the oil acting on the refrigerant discharge pressure Pd, that is, the oil in the oil reservoir 19 stored at the bottom of the discharge chamber 8 with the control valve 13, and the drive shaft 12. Acting in the same direction as the MAX transition direction.
[0010]
By the way, when the refrigerant discharge capacity of the compressor is increased, the valve opening degree of the control valve 13 may be increased. Then, the amount of oil flowing from the control valve 13 to the control pressure chamber 17 increases, the control pressure Pc increases, the force for sliding the drive shaft 12 in the MAX shift direction increases, and the drive shaft 12 moves in the MAX shift direction. Move to. In conjunction with this, the control plate 9 rotates counterclockwise, and the refrigerant confinement capacity increases.
[0011]
Further, 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 to the intake chamber 7. Can flow to the side.
[0012]
Therefore, the control pressure Pc in the control pressure chamber 17 is determined by the difference between the oil inflow amount from the control valve 13 side to the control pressure chamber 17 side and the oil outflow amount from the control pressure chamber 17 via the drive shaft clearance G.
[0013]
Here, considering the case where this type of compressor is mounted on a vehicle as a part of a car air conditioner system, the drive shaft clearance G may be reduced when the engine rotational speed of the vehicle rapidly decreases. This is because when the engine 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 is increased in order to keep the cooling capacity constant. For this purpose, the control pressure Pc may be increased 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 has restrictions on the valve mechanism, the control pressure Pc is increased by reducing the drive shaft clearance G.
[0014]
On the other hand, when the engine speed of the vehicle suddenly increases, 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 because when the engine rotational speed of the vehicle increases rapidly, the cooling capacity becomes too large contrary to the decrease, and the control pressure Pc in the control pressure chamber 17 needs to be rapidly decreased. This is because, 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 contributes to the decrease in the control pressure Pc.
[0015]
However, when the drive shaft clearance G is variable as described above, a new variable mechanism is required, which causes problems such as a complicated mechanism, a decrease in reliability and an increase in cost. There is.
[0016]
If the compromise of the drive shaft clearance G under these two situations is set in consideration of both the case where the engine speed of the vehicle suddenly increases and the case where it decreases as described above, the control pressure Pc However, it is difficult to increase the control pressure Pc because the oil in the control pressure chamber 17 flows out in a large amount through the drive shaft clearance G. Despite the fact that it takes time to obtain the refrigerant confinement capacity, or when it is desired to reduce the refrigerant confinement capacity by reducing the control pressure Pc, the oil in the control pressure chamber 17 hardly flows out through the drive shaft clearance G. However, it is difficult to reduce the control pressure Pc, and it takes time to obtain the minimum refrigerant confinement capacity. Under these two conditions, the increase or decrease in the cooling capacity is restored. It is not become to control the optimum refrigerant containment capacity can.
[0017]
[Problems to be solved by the invention]
The present invention has been made to solve the above-described conventional problems, and an object of the present invention is to control the refrigerant confinement capacity more optimally without complicating the equipment and increasing the cost, that is, the compressor. It is an object of the present invention to provide a variable capacity gas compressor that can appropriately control the refrigerant confinement capacity with respect to fluctuations in the cooling capacity.
[0018]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the present invention repeatedly compresses the volume, sucks the refrigerant from the intake chamber side by the volume change, confines and compresses the refrigerant, and then discharges the compressed refrigerant And a control plate that is rotatably provided between the compression chamber and the intake chamber, and that adjusts the rotation angle to increase or decrease the refrigerant confinement capacity of the compression chamber, and the control plate is rotated by sliding the drive shaft A control plate drive mechanism that moves, 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, and the suction pressure of the refrigerant in the intake chamber and the spring In a variable capacity gas compressor having a structure that slides according to the force relationship between the force and the control pressure in the control pressure chamber, the drive shaft and the slidable housing are accommodated. A gap for oil outflow forming a control pressure applied to the drive shaft is provided between the sleeve and the sleeve, and the entire drive shaft or only the gap forming portion of the drive shaft forming the gap is The sleeve is made of a material having a higher thermal expansion coefficient than the constituent material of the sleeve.
[0019]
The present invention is characterized in that the entire 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.
[0020]
In the present invention, the temperature of the drive shaft and the sleeve changes due to the temperature change of the refrigerant sucked in the intake chamber, and the gap between the drive shaft and the sleeve (drive shaft clearance) due to the difference in thermal expansion coefficient between the drive shaft and the sleeve. Thus, the refrigerant confinement capacity can be appropriately adjusted with respect to fluctuations in the cooling capacity of the compressor by changing the magnitude of the drive shaft clearance.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of a variable capacity gas compressor according to the present invention will be described in detail with reference to FIG.
[0022]
The basic structure of the compressor, for example, FIG. 2 to FIG. 3, will be described. The compression chamber 6 and the control plate 9 are provided inside the device. The change is repeated and the volume change 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 with respect to 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, and the rotational movement of the control plate 9 is controlled by the control plate driving mechanism. What is performed, that is, when the drive shaft 12 slides back and forth, the control plate 9 is rotated to the left and right in conjunction with this, and the refrigerant confinement capacity is increased or decreased. Since the slide is based on the relationship between the refrigerant suction pressure Ps, the spring force Fs, and the control pressure Pc, etc., the same members are denoted by the same reference numerals, and detailed description thereof is omitted. To do.
[0023]
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 is driven into the sleeve 14. The shaft 12 is disposed so as to be slidable back and forth. A drive shaft clearance G is provided between the drive shaft 12 and the sleeve 14. In order to make the drive shaft clearance G variable, the entire drive shaft 12 has a coefficient of thermal expansion greater than that of the constituent material of the sleeve 14. It is made of a large material.
[0024]
That is, in the compressor of the present embodiment, the constituent materials of the drive shaft 12 and the sleeve 14 are different, and the drive shaft clearance G changes depending on the difference in thermal expansion coefficient between the drive shaft 12 and the sleeve 14 based on the difference in the constituent materials. The mechanism is adopted. In short, the drive shaft clearance G can be varied, but the variable mechanism is not mechanical, and is due to the physical properties of the material such as the difference in thermal expansion coefficient between the drive shaft 12 and the sleeve 14.
[0025]
Further, the one end surface 12 a side (the side to which the refrigerant suction pressure Ps and the spring force Fs of the compression spring 21 are applied) of the drive shaft 12 protrudes from the opening end of the sleeve 14 and is exposed in the intake chamber 7. On the other hand, the other end surface 12 b (side to which the control pressure Pc is applied) of the drive shaft 12 is provided so as to face the control pressure chamber 17.
[0026]
The temperature of the drive shaft 12 is greatly affected by the temperature of a refrigerant (hereinafter referred to as “intake refrigerant”) that is led 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 itself that houses the drive shaft 12 is in the intake chamber 7 as described above, and the drive shaft one end surface 12 a side is exposed in the intake chamber 7. Accordingly, when the temperature of the intake refrigerant in the intake chamber 7 increases, the temperature of the drive shaft 12 and the sleeve 14 also increases accordingly, and conversely, when the temperature of the intake refrigerant in the intake chamber 7 decreases, the drive is driven accordingly. The temperature of the shaft 12 and the sleeve 14 is also lowered.
[0027]
Here, since the thermal expansion of the drive shaft 12 and the sleeve 14 is larger in the drive shaft 12, the drive shaft 12 is more thermally expanded than the sleeve 14 when the temperature of the sucked refrigerant is increased. G decreases, so that the amount of oil flowing from the control pressure chamber 17 to the intake chamber 7 via the drive shaft clearance G decreases, and the control pressure Pc in the control pressure chamber 17 tends to increase. . On the other hand, when the temperature of the suction refrigerant is lowered, the drive shaft 12 contracts more than the sleeve 14, so that the drive shaft clearance G becomes larger. Therefore, the oil from the control pressure chamber 17 via the drive shaft clearance G is increased. The amount of outflow increases and the control pressure Pc in the control pressure chamber 17 tends to be low.
[0028]
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.
[0029]
Also in the compressor of the present embodiment, for example, when the engine rotational speed of the vehicle rapidly decreases, the refrigerant discharge capacity of the compressor decreases and the cooling capacity decreases accordingly, so the refrigerant discharge capacity of the compressor is increased. Want to. The time when the refrigerant discharge capacity is desired to be increased is when the cooling capacity is insufficient and the refrigerant cannot be cooled, that is, when the temperature of the air ejected from the evaporator of the air conditioner system is the highest. The temperature of becomes higher. Therefore, due to the difference in thermal expansion coefficient between the drive shaft 12 and the sleeve 14, the drive shaft 12 is thermally expanded more than the sleeve 14, and thus the gap between the drive shaft 12 and the sleeve 14 is narrowed. That is, as shown in FIG. 1A, the drive shaft clearance G is reduced. Accordingly, 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 arrow A in the figure), and in conjunction with this, the control plate 9 rotates counterclockwise, and as a result, the refrigerant confinement capacity increases. Therefore, in this case, the refrigerant discharge capacity is increased, the cooling capacity of the compressor is increased, and it is possible to cool well early.
[0030]
Contrary to the above case, when it is desired to reduce the refrigerant discharge capacity of the compressor, that is, when the cooling capacity is excessive and the cooling is excessive, the temperature of the refrigerant sucked in the intake chamber 7 becomes low. Due to the difference in the coefficient of thermal expansion of 14, the drive shaft 12 contracts more than the sleeve 14 as shown in FIG. For this reason, the amount of oil flowing out from the control pressure chamber 17 to the intake chamber side via the drive shaft clearance G increases, and the control pressure Pc of the control pressure chamber 17 decreases in a short time. As a result, the drive shaft 12 is pushed back in the MIN transition direction (in the direction of arrow C in the figure) by the total force of the spring force Fs and the suction pressure Ps, and the control plate 9 rotates clockwise in conjunction with this, 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.
[0031]
As is clear from the above description, in the compressor according to the present embodiment, the entire drive shaft 12 is made of a material having a thermal expansion coefficient larger than that of the constituent material of the sleeve 14. Therefore, the drive shaft clearance G between the drive shaft 12 and the sleeve 14 is increased or decreased only by the physical property of the material, ie, the difference in thermal expansion coefficient between the drive shaft 12 and the sleeve 14 without using any mechanical mechanism. In addition, by changing the size of the drive shaft clearance G, it is possible to adjust the refrigerant confinement capacity appropriately for fluctuations in the cooling capacity of the compressor. Therefore, it is possible to control the refrigerant confinement capacity more optimally without causing deterioration in performance and cost increase.
[0032]
In the above embodiment, the entire drive shaft 12 is formed of a material having a higher thermal expansion coefficient than the sleeve 14, but a part of the drive shaft 12, specifically, the drive shaft clearance G is formed. Only the gap forming portion 12c of the drive shaft 12 may be formed of a material having a thermal expansion coefficient larger than that of the constituent material of the sleeve 14, specifically, the outer peripheral portion of the drive shaft. Since the drive shaft clearance G changes depending on the difference in thermal expansion coefficient between the gap forming portion 12c and the sleeve 14, the same effect as in the above embodiment can be obtained.
[0033]
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 forming the drive shaft clearance G is used. If the 12 gap forming portions 12c are formed of a plastic material and the sleeve 14 side is formed of an iron material, the effects of the above-described embodiment can be obtained due to the difference in coefficient of thermal expansion.
[0034]
【The invention's effect】
In the present invention, as described above, the coefficient of thermal expansion of the entire drive shaft or only the drive shaft gap forming portion forming the gap between the drive shaft and the sleeve (drive shaft clearance) is greater than that of the constituent material of the sleeve. It is composed of a large material. For this reason, without using any mechanical mechanism, the drive shaft clearance can be changed in size only by the physical properties of the material such as the difference in thermal expansion coefficient between the drive shaft and the sleeve. The change in the shaft clearance can quickly adjust the refrigerant confinement capacity appropriately for fluctuations in the cooling capacity of the compressor, leading to equipment complexity, resulting in lower reliability and higher costs. Therefore, it is possible to provide a variable capacity gas compressor that can control the refrigerant confinement capacity more optimally.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of a refrigerant confinement capacity control mechanism that 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 is reduced due to the difference in thermal expansion coefficient.
FIG. 2 is a cross-sectional view of a conventional variable displacement gas compressor.
3 is a cross-sectional view taken along line AA in FIG.
4 is a cross-sectional view taken along line BB in FIG.
5 is an explanatory diagram of a control mechanism for refrigerant confinement capacity in the conventional variable capacity gas compressor shown in FIG. 2; FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Casing 1a Front head 2 Cylinder 3 Rotor 4 Vane 5 Crescent cylinder inner space | gap 6 Compression chamber 7 Intake chamber 8 Discharge chamber 9 Control plate 10 Notch part 11 of control plate outer periphery Drive pin 12 Drive shaft 12a Drive shaft one 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)

By repeatedly changing the size of the volume, the refrigerant is sucked in from the intake chamber side, confined and compressed, and then the compression chamber for discharging the compressed refrigerant,
A control plate that is rotatably provided between the compression chamber and the intake chamber, and that changes the refrigerant confinement capacity of the compression chamber by adjusting the rotation angle;
A control plate drive mechanism for rotating the control plate by sliding the drive shaft,
The drive shaft is provided such that one end surface side thereof is exposed to the intake chamber and the other end surface faces the control pressure chamber, and the refrigerant suction pressure, the spring force, and the control pressure in the control pressure chamber are provided. In the variable capacity gas compressor with a structure that slides by the force relationship with
Between the drive shaft and a sleeve for slidably storing the drive shaft, an oil outflow gap that forms a control pressure applied to the drive shaft is provided,
The variable displacement gas compressor according to claim 1, 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 thermal expansion coefficient than the constituent material of the sleeve. 2. The variable capacity gas compressor according to claim 1, wherein the entire 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.

Images