JPS6287680A - Control valve for variable discharge compressor - Google Patents

Abstract

PURPOSE:To promply decrease a discharge of a compressor so as to improve an acceleration characteristic of an engine when it is rapidly accelerated at a high temperature of the outside air in midsummer or the like, by controlling communication of a crank chamber with a suction side and discharge side through means responsively sensing both suction pressure and discharge temperature. CONSTITUTION:A pin-shaped value unit 30, which controls communication of a suction chamber 2 with a crank chamber 8, is driven by a bellows 24 responsively sensing a suction pressure. Said pin-shaped valve unit 30 is actuated so as to open a spool valve 50, which controls communication of a discharge chamber 6 with the crank chamber 8, against a spring 52. Further a means 51a, having a built-in wax temperature-sensing plate 51 and respectively sensing a temperature of the outside air, acts on said spring 52. And if the temperature of the outside air increases to a high degree, said means 51a acts so as to decrease a preset spring pressure of the spool valve 50 by the spring 52.

Description

[Detailed Description of the Invention] (Field of Industrial Application) This invention relates to a control valve for a variable displacement compressor used in a vehicle air conditioner, and more specifically to a control valve that is sensitive to suction pressure and discharge temperature. This relates to a control valve that controls the discharge amount.

(Prior Art) As a variable displacement compressor used in a vehicle air conditioner, there is one disclosed in, for example, Japanese Patent Application Laid-open No. 158382/1982. As shown in FIG. 3, the compressor disclosed in JP-A-58-158382 has a refrigeration cycle including an accumulator 1, a condenser 14, an orifice pipe 11, an evaporator 9, and an accumulator 1. Suction chamber 2 into which refrigerant at bottom pressure is sent
As the piston 3 moves forward and backward, the compressed high-pressure refrigerant enters the working chamber from the suction chamber 2 through the suction valve 4 and enters the discharge valve 5.
It has a discharge chamber 6 through which the discharge is discharged. The suction chamber 2 communicates with the crank chamber 8 via channels 7a and 7b and a hole in the control valve 16, which will be described later, and the discharge chamber 6 also communicates with the crank chamber 8.
It communicates with the crank chamber 8 via 0a, 10b and a hole in the control valve 16.

A swash plate 12 is provided in the crank chamber 8 and moves the piston 3 forward and backward as the drive shaft 13 rotates. This swash plate 1
2, when the pressure in the crank chamber 8 becomes approximately equal to the pressure in the suction chamber 2, the angle of inclination becomes maximum, increasing the stroke of the piston 3, maximizing the amount of refrigerant discharged, and increasing the pressure in the crank chamber 8. When the pressure in the suction chamber 2 becomes higher than the pressure in the suction chamber 2, the angle of inclination is decreased to reduce the stroke of the piston 3 and the discharge amount. Control of the discharge amount, that is, adjustment of the pressure in the crank chamber 8, is performed by a control valve 16 provided in the head 15, in which the suction chamber 2 and the discharge chamber 6 are formed. The control valve 16 switches and controls the communication between the suction chamber 2 and the crank chamber 8 and the communication between the discharge chamber 6 and the crank chamber 8 in response to the pressure in the suction chamber 2 (suction pressure) and the pressure in the discharge chamber 6 (discharge pressure). The pressure in the crank chamber 8 is thereby changed. FIG. 4 shows the configuration of the control valve 16 in detail, and 18 in the figure is a bellows fitted and fixed into one end (large diameter end) 19a of the stepped valve hole 19 formed in the head 15. The valve body 20 is fitted into the valve hole 19 from the middle to the other end 19b, and one end of which is connected to one end of the bellows cover 18. A gap between the inner wall surface of the valve hole 19 and the outer peripheral surfaces of the bellows cover 18 and the valve body 20 is sealed by a sealing member 22 . Reference numeral 23 denotes a hole that communicates between the shaft hole 18a of the bellows cover 18 and one end 19a of the valve hole 19. It communicates with the suction chamber 2. A bellows 24 is provided in the shaft hole 18a of the bellows cover 18 and has one end closed.

One closed end of the bellows 24 is fixed to the bottom of the shaft hole 18a, and the other end (open end) is unrestricted and sealed by the end member 25. The interior space of the bellows 24 is evacuated. 26 is a coil spring that is contracted in the internal space of the degassed bellows (hereinafter referred to as degassed bellows) 24 and always biases the degassed bellows 24 in the direction of expansion; 27 is the end member 2;
5, and one end of which has a pointed head 27a protrudes from the end member 25. 28 is the valve body 20 and the end member 2
This is a coil spring that is compressed between the degassing bellows 24 and the degassing bellows 24 and is always biased in the direction of contracting the degassing bellows 24. Pointed head 27
The position of a is determined by the sum of the loads of the springs 26 and 28 and the suction pressure load acting on the degassing bellows 24. 30
is a bottle-shaped valve body fitted into a stepped shaft hole 31 of the valve body 20 so as to be slidable in the axial direction. A pointed head 27a at one end of the output rod 27 is fitted into a blind hole 32 drilled in the rear end surface of the bottle-shaped valve body 30, and by this engagement, the output rod 27 and the bottle-shaped valve body 30 are connected. can move together towards the top of the diagram.

34 is a hole through which the shaft hole 31 of the valve body 20 and a portion 19c of the valve hole 19 communicate with each other. This hole 34, one end 3 of the shaft hole 31
The shaft hole 18a of the bellows cover 18 and the crank chamber 8 communicate with each other via 1a, a portion 19c of the valve hole 19, and the flow path 7b, and as a result, the suction chamber 2 and the crank chamber 8 communicate with each other. Become. 35 is a valve seat provided at one end 31a of the shaft hole 31, and when the bottle-shaped valve body 30 moves upward in the figure and the shoulder portion 30a of the bottle-shaped valve body 30 comes into close contact with this valve seat 35, One end 31a of the shaft hole 31 is closed, and the suction chamber 2
Communication between the crank chamber 8 and the crank chamber 8 is cut off. 37 is the other end 31b of the shaft hole 31 and the one end 1 of the valve hole 19.
9d, and 38 is a hole communicating with the other end 3 of the shaft hole 31.
It is a fitting member fitted to 1b. The shaft hole 38a of the fitting member 38, the other end 19b of the valve hole 19, the flow path 10a, the other end 311 of the shaft hole 31), the hole 37, and the part 19 of the valve hole 19.
d, the discharge chamber 6 and the crank chamber 8 communicate with each other via the flow path 10b. The tip end portion 30b of the bottle-shaped valve body 30 is loosely inserted into the shaft hole 38a of the fitting member 38 from one end thereof. Reference numeral 39 denotes a ball valve body housed in the shaft hole 38a of the fitting member 38, and the ball valve body 39 is in close contact with a valve seat 40 formed in the shaft hole 38a toward the other end. It is possible to close the hole 38a and cut off communication between the discharge chamber 6 and the crank chamber 8. 41 is a fitting member 38
A spring seat 42 formed in the opening on the other end side of the shaft hole 38a.
This is a coil spring that is compressed between the ball valve body 39 and the ball valve body 39, and always urges the ball valve body 39 to come into close contact with the valve seat 4o.

Note that 43 is a filter.

The control valve 16 having the above configuration operates as follows.

When the rotation speed of the compressor, in other words, the engine speed of the vehicle, increases or the heat load conditions (for example, outside temperature) are relaxed, the pressure in the suction chamber 2 (suction pressure) decreases, so the suction chamber 2 and i The pressure in the shaft hole 18a of the bellows cover passing through it also decreases, and when this pressure falls below a predetermined value, the degassing bellows 24 expands and the output rod 27 pushes the bottle-shaped valve body 3o upward in the figure. As a result, the shoulder portion 30a of the bottle-shaped valve body 3o comes into close contact with the valve seat 35, and the suction chamber 2 and crank chamber 8
At the same time, the tip end rond part 30b of the bottle-shaped valve body 3o presses the pawl valve body 39, and resists the biasing force of the coil spring 41 and the discharge pressure acting on the pawl valve body 39. 39 is separated from the valve seat 4o.

Therefore, the shaft hole 38a of the fitting member 38, which had been closed until then, is opened, and the crank chamber 8 is communicated with the discharge chamber 6.
Since the pressure in the crank chamber 8 increases, the angle of inclination of the swash plate 12 decreases, and the amount of refrigerant discharged decreases.

The advantage of the control valve 16, which operates in response to suction pressure and discharge pressure, is that when the outside temperature is high, the temperature (pressure) of the evaporator 9 (see Figure 3) of the refrigeration cycle can be adjusted to the freezing temperature ( If the temperature is maintained at a temperature slightly higher than the pressure), the temperature (pressure) of the evaporator 9 will be relatively high when the outside air temperature is low, and the power consumption will be reduced accordingly. It is.

(Problem to be solved by the invention) By the way, when a vehicle running at low speed while operating the compressor at its maximum discharge capacity when the outside temperature is high, such as in the middle of summer, suddenly accelerates, the load on the engine reaches its maximum, causing the vehicle to accelerate. Bad sex. Therefore, it is necessary to quickly reduce the discharge amount of the compressor of the air conditioner, which uses the engine as the drive source, to reduce its operating capacity, thereby reducing the load on the engine and improving acceleration performance. control valve 1
6, the discharge pressure acts directly on the pawl valve body 39, so when the discharge pressure increases, the pawl valve body 3
9 has the characteristic that the force with which it comes into pressure contact with the valve seat 40 becomes stronger. Therefore, in order to resist this strong force and separate the ball valve body 39 from the valve seat 40 and communicate the crank chamber 8 with the discharge chamber 6 to reduce the capacity of the compressor, the bottle-shaped valve body 30 is The force with which the body 39 is pressed must be strong enough to withstand the strong force caused by this high discharge pressure. In other words, the pressure in the suction chamber 2 (suction pressure) must be reduced to a low pressure commensurate with the high discharge pressure to increase the stretching force of the degassing bellows 24. However, during rapid acceleration, a decrease in suction pressure and an increase in discharge pressure occur simultaneously, so the suction pressure decreases enough to apply a large stretching force to the degassing bellows 24, causing the bottle-shaped valve body 3o to adjust to the discharge pressure. It takes time to resist and separate the ball valve body 39 from the valve seat 4o. Therefore, it was not possible to improve acceleration.

(Means and effects for solving the problems) The present invention was made by focusing on the problems of the prior art as described above. There is a suction pressure sensitive means that operates to cause the control valve to communicate between the crank chamber and the discharge chamber when the pressure in the suction chamber falls below a predetermined value, and a suction pressure sensitive means that operates in response to the discharge temperature, and as the discharge temperature increases, the control valve operates in response to the discharge temperature. and a discharge temperature sensitive means for operating the suction pressure sensitive means at a suction chamber pressure lower than the predetermined value, and the difference between the upper limit rate of the discharge pressure and the discharge temperature, that is, the discharge temperature is the discharge pressure The above-mentioned problem is solved by utilizing the time delay until the temperature corresponding to the temperature is reached, and the time delay due to the heat mass of the discharge temperature sensitive means.

(Example) Hereinafter, this invention will be explained based on examples.

FIG. 1 is a front sectional view of a variable discharge rate compressor provided with an embodiment of a control valve according to the present invention, and FIG. 2 is an enlarged view of the control valve of FIG. 1. First, the configuration will be explained, and the same parts as before will be given the same reference numerals and their explanation will be omitted.
Only the different parts will be explained. In the control valve 46 shown in FIG. 2, reference numeral 48 denotes a fitting member fitted into the other end 19b of the valve hole 19 and the other end 3ib of the shaft hole 31 of the valve body 20 at its step-shaped outer circumference. It is. This fitting member 4
The tip rod portion 30b of the bottle-shaped valve body 30 is loosely inserted into one end side of the shaft hole 48a. Further, a sleeve 49 is fitted into the shaft hole 48a, and the shaft hole 4 of the sleeve 49
A spool valve body 50 is slidably fitted into 9a. Then, this spool valve body 50 presses the front end surface of the tip rod portion 30b with its tip and moves the bottle-shaped valve body 30 downward in the figure, so that it comes into close contact with the valve seat 53 formed in the shaft hole 48a, and the shaft Hole 48a can be closed.

A wax temperature-sensitive pellet 51 is fitted into the other end of the shaft hole 48a of the fitting member 48 and serves as a discharge temperature sensing means. The main body (temperature sensing part) 51a of the wax temperature-sensitive pellet 51 in which wax is sealed is located in the discharge chamber 6, and its piston rod 51b, which protrudes and retreats as the wax expands and contracts, is inserted into the shaft hole of the sleeve 49. 49a so that it can move forward and backward. And this piston rod 5
A coil spring 52 is compressed between the front end surface of the spool valve body 1b and the rear end surface of the spool valve body 50.
The tip of the valve body 30 is biased in such a direction that the tip thereof is always in contact with the tip surface of the tip portion 30b of the bottle-shaped valve body 30. S5 is a hole that is formed in the fitting member 48 and communicates the shaft hole 48a of the fitting member 48 with the discharge chamber 6, and 56 is a hole that is formed in the fitting member 48 and connects the part 19d of the valve hole 19 with the shaft of the sleeve 49. Hole 49a
It is a hole that communicates with the As a result, the discharge chamber 6 and the crank chamber 8 are connected to the hole 55, the shaft hole 48a, and the other end 31b of the shaft hole 31.
, the hole 37, a portion 19d of the valve hole 19, and the flow path 10b. The configuration of the other parts of the control valve 46 and the configuration of the compressor are the same as those of the prior art.

Next, the operation of the control valve 46 will be explained. When the heat load conditions are relaxed, such as when the rotational speed of the compressor, that is, the engine of the vehicle increases, or when the outside air temperature decreases, the discharge amount decreases due to the same effect as described in the related art.

That is, as the pressure in the suction chamber 2 (suction pressure) decreases, the pressure in the shaft hole 18a of the bellows cover 18 that communicates with the suction chamber 2 also decreases, and when this pressure falls below a preset value, the suction pressure decreases. The degassing bellows 24 as a sensitive means expands and the output rod 27 pushes the bottle-shaped valve body 30 upward in the figure. As a result, the shoulder portion 30a of the bottle-shaped valve body 30 comes into close contact with the valve seat 35 to cut off communication between the suction chamber 2 and the crank chamber 8, and at the same time, the tip loft portion 3 of the piston-shaped valve body 30
0b presses the spool valve body 50 against the biasing force of the coil spring 52 and separates it from the valve seat 53.

Therefore, the shaft hole 48a of the fitting member 48, which had been closed by the spool valve body 50, is opened and the crank chamber 8 communicates with the discharge chamber 6, and the pressure inside the crank chamber 8 increases, so that the swash plate 12 The inclination angle decreases and the amount of refrigerant discharged decreases. Note that at this time, the heat load conditions are gentle, such as the outside temperature being low, so the discharge temperature is also relatively low, and the wax temperature-sensitive pellet 51 has a low wax expansion rate, so the piston rod 51b thereof does not protrude very much. Therefore, the force pressing the spool valve body 50 against the valve seat 53 is not very strong, and the crank chamber 8 can be brought into communication with the discharge chamber 6 even if the suction pressure becomes slightly lower than a predetermined value. On the other hand, when the outside air temperature becomes high and the heat load conditions become severe, the discharge pressure and discharge temperature become high. Thermal expansion causes the piston rod 51b to protrude. The protruding piston rod 51
In order to further compress the coil spring 52, the spool valve body 50 is urged with a strong force. Therefore, the crank chamber 8 and the discharge chamber 6 communicate with each other only after the suction pressure is reduced to a low pressure commensurate with the high spring load. As described above, the control valve 46 according to the present invention, which operates in response to suction pressure and discharge temperature, has a By maintaining the temperature (pressure) of the evaporator 9 of the refrigeration cycle at a temperature slightly higher than the freezing temperature (pressure) as shown in Figure 3, maximum effectiveness can be achieved when the outside temperature is high. It is also possible to reduce power consumption when the outside temperature is low.

Furthermore, the control valve 46 according to the present invention can improve acceleration when a vehicle running at low speed suddenly accelerates while operating the air conditioner to its maximum capacity when the outside temperature is high, such as in the middle of summer. can. In other words, during sudden acceleration, a decrease in suction pressure and an increase in discharge pressure occur simultaneously, but there is a difference in the rate of increase in discharge pressure and discharge temperature, and the discharge temperature reaches a temperature corresponding to the discharge pressure. There will be a time delay. Furthermore, a time delay occurs due to the heat mass of the discharge temperature sensitive means. Therefore, the time required for the piston rod 51b to protrude due to thermal expansion of the wax in the wax temperature-sensitive pellet 51 due to a one-point increase in the discharge temperature, and for the force that presses the spool valve body 50 against the valve seat 53 to increase,
As the suction pressure decreases, the degassing bellows 24 expands, bringing the shoulder 30a of the pin-shaped valve body 30 into pressure contact with the valve seat 35, cutting off communication between the crank chamber 8 and the suction chamber 2, and opening the tip and throat. Since the time required for the portion 30b to press the spool valve body 50 to separate it from the valve seat 53 and communicate the crank chamber 8 and the discharge chamber 6 is shorter, the suction pressure decreases and the discharge pressure increases at the same time. Even though they occur in parallel, the pressure within the crank chamber 8 is quickly switched. As a result, the discharge amount of the compressor is quickly reduced, in other words, the operating capacity of the compressor is reduced quickly, the load on the engine is reduced, and a margin is created, which improves acceleration.

(Effects of the Invention) As explained above, according to the present invention, when the outside temperature is high, the discharge amount of the compressor can be maximized to obtain a sufficient cooling effect, and when the outside temperature is low, the discharge amount can be maximized. It is possible to reduce the amount and power consumption. Furthermore, various effects can be obtained, such as being able to improve the acceleration performance when a vehicle running at low speed suddenly accelerates while operating the air conditioner to the maximum extent when the outside temperature is high.

[Brief explanation of drawings]

Fig. 1 is a front sectional view of a variable discharge rate compressor equipped with an embodiment of the control valve according to the present invention, Fig. 2 is an enlarged view of the control valve portion of Fig. 1, and Fig. 3 is a conventional control valve. FIG. 4 is a front sectional view of a variable discharge rate compressor provided with a valve, and FIG. 4 is an enlarged view of the control valve portion of FIG. 3. 2... Suction chamber, 3... Piston, 6... Discharge chamber, 8... Crank chamber, 12... Swash plate, 24 ...Deaeration bellows (suction pressure sensitive means), 4
6... Control valve, 51... Wax temperature sensitive pellet (discharge temperature sensitive means). 24 Part 3 ahead I\Rokyu (5 steps to 1 sense of kori) 4
6jo II jYl'l dialect

Claims (2)

[Claims] (1) In a variable displacement compressor that controls the pressure in the crank chamber through communication between the crank chamber and the suction side and/or the discharge side, and controls the discharge rate by adjusting the inclination angle of the swash plate based on the pressure. . A control valve for a variable discharge rate compressor, characterized in that the communication is performed by means sensitive to both suction pressure and discharge temperature. (2) The control valve for a variable discharge rate compressor according to claim 1, wherein the discharge temperature sensitive means is a wax temperature sensitive pellet.