JP2002310064A - Variable displacement compressor for air conditioning - Google Patents

Abstract

PROBLEM TO BE SOLVED: To quickly change the capacity of a compressor to the maximum capacity in starting a compressor. SOLUTION: A cylinder block 1 is provided with a by-pass passage 13 communicating an intake port 31 with a crank chamber 20, and a bi-metal valve 16 is fitted to the end of the passage. Immediately after the compressor starts, when the temperature in the crank chamber 20 is low, the bi-metal valve 16 is opened, so that a liquid refrigerant in the crank chamber 20 is sucked in the intake port 31 through the passage 13. With a temperature rise in the crank chamber 20, the bi-metal valve 16 is closed so that the compressor is controlled to the capacity corresponding to the operation of a control valve 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioning variable displacement compressor suitable for use in a vehicle air conditioner.

[0002]

2. Description of the Related Art Conventionally, the suction pressure of refrigerant flowing into a compressor or the discharge pressure flowing out of a compressor is guided to a crank chamber through a control valve, whereby the pressure in the crank chamber is controlled to control the swash plate in the crank chamber. There is known an air conditioning variable displacement compressor in which the discharge angle is controlled by changing the inclination angle of the air conditioner.
No. 8382).

[0003]

When the vehicle is parked (leaved), the engine cools down and a temperature difference is generated between the engine room and the interior of the vehicle. Refrigerant accumulates in the crankcase. The accumulated refrigerant condenses and liquefies in the crankcase when the ambient temperature around the compressor is low. When the compressor is operated in this state, the suction pressure or the discharge pressure is guided to the crank chamber through the control valve. That is, compared to when the refrigerant is not liquefied,
The pressure in the crankcase increases. As a result, the swash plate cannot be immediately inclined to an appropriate state, and sufficient cooling capacity may not be obtained. This phenomenon is continued until the temperature of the crank chamber rises and the liquid refrigerant remaining in the crank chamber is gasified and absorbed by the suction pressure, and continues until the pressure in the crank chamber drops to an appropriate value, during which the cooling capacity is insufficient.

[0004] It is an object of the present invention to provide an air conditioning variable displacement compressor which can quickly obtain an optimum cooling capacity at the start of the compressor even when the refrigerant is condensed and liquefied in the crank chamber.

[0005]

An embodiment will be described with reference to the accompanying drawings. (1) The invention of claim 1 guides the suction pressure from the suction chamber 31 or the discharge pressure from the discharge chamber 32 to the crank chamber 20, and controls the discharge capacity of the compressor according to the refrigerant pressure in the crank chamber 20. Applied to variable displacement compressors for air conditioning. The above-described object is achieved by providing the bypass passage 13 that connects the crank chamber 20 and the suction chamber 31 and the valve device 16 that opens and closes the bypass passage 13 according to the temperature in the crank chamber 20. (2) The invention according to claim 2 is the air-conditioning variable displacement compressor according to claim 1, wherein the valve device is a bimetal 16
It is constituted by (3) The invention of claim 3 is the variable displacement compressor for air conditioning according to claim 2, wherein the bypass passage 13 is opened when the bimetal 16 is at a temperature at which the refrigerant in the crank chamber 20 liquefies. It is formed so as to close the bypass passage 13 when the temperature of the refrigerant in the inside is gasified. (4) The invention according to claim 4 is the variable displacement compressor for air conditioning according to claim 2 or 3, wherein
Is mounted so as to cover the end of the bypass passage 13 in the crank chamber 20. (5) The invention of claim 5 is the variable displacement compressor for air conditioning according to any one of claims 1 to 4, wherein the bypass passage 13 is provided near the lower end of the crank chamber 20 and the suction chamber 3.
1 is formed so as to communicate therewith.

[0006] In the section of the means for solving the above-mentioned problems, which explains the configuration of the present invention, the drawings of the embodiments are used to make the present invention easier to understand. However, the present invention is not limited to this.

[0007]

According to the present invention, the following effects can be obtained. (1) According to the first aspect of the present invention, the crank chamber and the suction chamber are connected by the bypass passage, and the bypass passage is opened and closed according to the temperature in the crank chamber. Therefore, the refrigerant condensed and liquefied in the crank chamber. Is flowed into the suction chamber via the bypass passage, and the optimum cooling capacity can be obtained quickly when the compressor is started. (2) According to the second aspect of the invention, since the bypass passage is closed by the bimetal, the configuration is easy. (3) According to the third aspect of the invention, the bypass passage is opened when the temperature of the refrigerant in the crankcase is liquefied, and the bypass passage is closed when the temperature of the refrigerant is gasified. The liquefied refrigerant can be reliably guided to the intake chamber. (4) According to the invention of claim 4, since the bimetal is attached so as to cover the end of the bypass passage in the crank chamber, when the bypass passage is closed by the temperature, the bimetal member closes the passage by a pressure difference. Since the above force acts, the sealing performance is improved. (5) According to the fifth aspect of the invention, since the bypass passage is formed so as to communicate the vicinity of the lower end of the crank chamber with the suction chamber, more liquefied refrigerant accumulates near the lower end of the crank chamber due to gravity. It can lead to the suction chamber.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a sectional view of an air conditioning variable displacement compressor according to an embodiment of the present invention. The variable displacement compressor includes a cylinder block 1 (see FIG. 3) having a plurality of cylinders 10 arranged at substantially equal intervals in a circumferential direction, and a casing 2 that forms a crank chamber 20 by covering one end surface of the cylinder block 1. And a cylinder head 3 attached to the other end face of the cylinder block 1 and having a suction port 31 and a discharge port 32 corresponding to each cylinder 10.

A rotary shaft 4 is pivotally supported at the center of the cylinder block 1 and the casing 2, and the rotary shaft 4 is driven to rotate by an engine (not shown) via a V pulley 5 on the outer peripheral portion of the casing 2. A drive lug 41 that rotates integrally with the rotary shaft 4 is mounted on the rotary shaft 4, and a rotary plate 43 is attached to the drive lug 41 via a journal pin 42.
(Swash plate) is attached. The journal pin 42 can move in the cam groove 44, and with this movement, the rotary plate 43 tilts, and the tilt angle changes. The non-rotary wapple 21 is attached to the rotary plate 43 via a thrust bearing 45 and a ball bearing 46, and the non-rotary wapple 21 swings in the axial direction with the rotation of the rotary plate 43.

[0010] The rod 1 is
A piston 12 that is slidable in the cylinder 10 is connected to the piston 1 via the first piston 1. The piston 12 reciprocates with an operation stroke corresponding to the tilt angle of the rotary plate 43 with the swing of the rotary whip 21, that is, with the rotation of the rotary plate 43. Thus, the refrigerant sucked from the suction port 31 is compressed and compressed, and is discharged from the discharge port 32. The tilt angle of the rotary plate 43 is controlled by a control valve 6 inserted in the cylinder head 3.

FIG. 2 is a sectional view of the control valve 6. The control valve 6 includes a suction-side valve 61, a discharge-side valve 62, and a control unit 63 including a pressure-responsive bellows for switching and controlling these two valves 61, 62 according to a set pressure. The control valve 6 has openings 64 to 66. As shown in FIG. 1, the opening 64 is formed in the passage 3 formed in the cylinder head 3.
3, the opening 65 communicates with the crank chamber 20 through the passages 34, 35 formed in the cylinder head 3 and the passage 47 formed in the rotating shaft 4, and the opening 66 Passage 3 formed in cylinder head 3
6 and communicate with the discharge port 31.

When the suction pressure of the compressor becomes equal to or higher than the set pressure, the discharge valve 62 is closed and the suction valve 61 is opened by the control of the control unit 63 as shown in FIG. Is introduced into the suction port 31 through the openings 65 and 66. Thereby, the crankcase 2
0, and a pressure difference is generated before and after each piston 12, in other words, between the piston chamber and the casing chamber. This pressure difference increases the inclination angle of the rotary plate 43, and causes the piston 12 to discharge refrigerant. The amount increases. On the other hand, when the suction pressure falls below the set pressure, FIG.
As shown in (b), the suction valve 61 is closed and the discharge valve 62 is opened in response to the control of the control unit 63, and the discharge pressure is introduced into the crank chamber 20 through the openings 64 and 65. As a result, the pressure in the crank chamber 20 increases, and the pressure difference between the front and rear of each piston 12 causes the rotary plate 4 to rotate.
3 becomes small, and the refrigerant discharge amount decreases. In this manner, the casing chamber 20 is controlled by the control valve 6.
The inclination angle of the rotary plate 43 is automatically adjusted by selectively introducing the suction pressure or the discharge pressure therein.

FIG. 3 is a front view and a side view (partially sectional view) showing the shape of the cylinder block 1. A bypass passage 13 penetrating in the axial direction is provided in a lower phase of the cylinder block 1, and an end 14 of the passage 13 is chamfered. A bimetal valve 16 is attached to the entrance of the bypass passage 13 by a bolt 15. The bimetal valve 16 is formed by joining two metal plates having different coefficients of thermal expansion. As shown in FIG. 4 which is an enlarged view of a part a in FIG. The seal member 17 is formed of a material having a relatively low hardness (for example, brass). In the drawing, the right plate 16R has a larger coefficient of thermal expansion than the left plate 16L, whereby the bimetal valve 16 is deformed as the temperature rises as shown in FIG. 17 is the bypass passage 1
3 abuts the inlet end 14. The bimetal valve 16 is formed so as to be deformed as shown in the diagram (a) at the temperature at which the refrigerant is liquefied, and as shown in the diagram (b) at the temperature at which it is gasified.

Next, the characteristic operation of this embodiment will be described. When the compressor operates, if the amount of heat absorbed by the amount of refrigerant gas passing through the evaporator is large (for example, when driving at low speed or when the outside temperature is high), the suction pressure of the refrigerant gas rises above the set pressure. Then, as shown in FIG. 2A, the suction side valve 61 of the control valve 6 is opened. As a result, the pressure in the crank chamber 20 increases
7, 35, 34, are introduced into the suction port 31 via the control valve 6 (arrows in FIG. 1). At this time, when the temperature in the crankcase 20 is low (for example, when the engine is first started in the morning), the bimetal valve 16 is deformed as shown in FIG. Is in communication with Therefore, the crankcase 20
Even if refrigerant condensed and liquefied accumulates, the refrigerant quickly moves to the suction port 31 in the liquid phase via the bypass passage (arrow). As a result, the crankcase 20
Is responsively reduced to a value corresponding to the response of the control valve 6, the inclination angle of the rotary plate 43 is increased, and the operating stroke of the piston 12 is maximized.

The operation of the compressor causes the crank chamber 20
When the internal temperature rises, the bimetal valve 16 is deformed as shown in FIG. 4B, and the seal member 17 contacts the inlet end 14 of the bypass passage 13. The temperature difference in the crank chamber 20 before and after the operation of the compressor is about 20 degrees or more. In this case, the crankcase 2
Since the pressure of 0 is higher than the suction pressure, the pressure difference pushes the bimetal valve 16 against the passage end 14, and the sealing performance of the seal member 17 is improved.

On the other hand, when the amount of heat absorbed relative to the amount of the refrigerant gas passing through the evaporator is small (for example, when traveling at high speed or when the outside air temperature is low), the suction pressure of the refrigerant gas becomes low. When the suction pressure falls below the set pressure, FIG.
As shown in (b), the discharge side valve 62 of the control valve 6 is opened. As a result, the discharge pressure is controlled through the control valve 6 and the passages 34, 35, 47 through the crank chamber 20.
(Arrow), and into the crank chamber 20 through the piston bore gap (arrow). At this time, as described above, the bypass passage 13 is closed by the bimetal valve 16 except when the temperature is low, and the outflow from the bypass passage 13 is prevented. As a result, the pressure in the crank chamber 20 increases, the difference from the discharge pressure decreases, and the operating stroke of the piston 12 decreases.

As described above, according to the present embodiment, the bypass passage 13 is formed in the cylinder block 1 and its inlet is closed by the bimetal valve 16, so that when the liquefied refrigerant is accumulated in the crank chamber 20, The liquefied refrigerant flows to the suction port 31 via the bypass passage 13.
As a result, the rotary plate 43 can be quickly tilted to the maximum tilt angle, and the optimum cooling capacity can be immediately obtained. In addition, since the bimetal valve 16 is deformed as the temperature rises and the bypass passage 13 is closed, excess refrigerant is prevented from flowing from the crank chamber 20 to the suction port 31, and the compressor is operated in response to the control valve 6. The capacity can be controlled.
In this case, since the passage 13 is closed when the temperature of the refrigerant in the crank chamber 20 is gasified, the liquefied refrigerant in the crank chamber 20 can be reliably guided to the suction port 31. At this time, the bimetal valve 16 is connected to the inlet end 1 of the passage 13 on the surface of the bimetal valve 16.
Since a pressure is applied to the bimetal valve 4, the sealing performance of the bimetal valve 16 is ensured. Further, since the bypass passage 13 is provided so as to connect the vicinity of the lower end of the crank chamber 20 with the suction port 31, more liquefied refrigerant accumulated near the lower end of the crank chamber 20 is guided to the suction port 31 by gravity. be able to.

In the above-described embodiment, the bimetal valve 16 is used as a member for opening and closing the bypass passage 13. However, the present invention is not limited to this, and various structures that open and close according to the temperature in the crank chamber 20 are employed. it can. For example, a temperature sensor may be used to detect the temperature in the crank chamber 20 and a valve driven according to the detected value may be used. Also,
The shape of the bypass passage 13 is not limited to the embodiment.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a configuration of an air conditioning variable displacement compressor according to an embodiment of the present invention.

FIG. 2 is a sectional view of a control valve included in the air conditioning variable displacement compressor according to the embodiment.

FIG. 3 is a front view and a side view of a cylinder block constituting the air conditioning variable displacement compressor according to the present embodiment.

FIG. 4 is an enlarged view of a bimetal valve attached to a cylinder block.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Cylinder block 6 Control valve 13 Bypass passage 16 Bimetal 20 Crank chamber 31 Suction port 32 Discharge port 43 Rotary plate

Claims (5)

[Claims] 1. A variable displacement compressor for air-conditioning, which guides a suction pressure from a suction chamber or a discharge pressure from a discharge chamber to a crank chamber and controls a discharge capacity of the compressor in accordance with a refrigerant pressure in the crank chamber. A variable displacement compressor for air conditioning, comprising: a bypass passage that communicates between a chamber and a suction chamber; and a valve device that opens and closes the bypass passage according to the temperature in the crank chamber. 2. The variable displacement compressor for air conditioning according to claim 1, wherein the valve device is made of a bimetal. 3. The variable displacement compressor for air conditioning according to claim 2, wherein the bimetal opens the bypass passage at a temperature at which the refrigerant in the crank chamber liquefies, and the refrigerant in the crank chamber gasifies. A variable displacement compressor for air conditioning, which is formed so as to close the bypass passage at a temperature. 4. The variable displacement compressor for air conditioning according to claim 2, wherein the bimetal is attached so as to cover an end of the bypass passage in the crank chamber. . 5. The variable displacement compressor for air conditioning according to claim 1, wherein the bypass passage is formed so as to communicate a vicinity of a lower end of the crank chamber with a suction chamber. A variable displacement compressor for air conditioning characterized by the following.