JPS6245993A - Volume control mechanism for variable delivery compressor - Google Patents

Abstract

PURPOSE:To obtain the stable delivery switching control by connecting a deliv ery pipe passage and a pressure working chamber when the load for a cooler is high and disconnecting the said connection when the said load is low. CONSTITUTION:When the load for a cooler is high, a spool valve 33 is opened so that the after-intake-and-throttling pressure on the intake flange (7) side becomes equal to the before-intake-and-throttling pressure on the evaporator (E) side. After this, a seal valve 41 is opened by a spool valve 39, and the deliv ery pressure in a delivery pipe passage 32 is sent to a pressure working chamber 29. At the same time, a bypass passage 26 is closed to let the compressor run into 100% capacity operation. On the other hand, when the load for a cooler is low, the reversed operation is carried out. With this contrivance, a stable capacity switching control can be obtained without being affected by the varia tion of differential pressure between the intake pressure and the delivery pres sure, which is caused by the factors other than the load for the cooler.

Description

[Detailed Description of the Invention] Purpose of the Invention (Field of Industrial Application) This invention relates to a variable capacity rotary compressor, and more specifically, to capacity control of a variable capacity rotary compressor that accurately switches the capacity according to the cooling load. It is about the mechanism.

(Prior art) Conventionally, variable capacity compressors have been used as variable capacity compressors that automatically control compression capacity in accordance with changes in indoor cooling load.
In Japanese Patent Application Laid-open No. 58-222994, the applicant of the present application has proposed a method using the change in the differential pressure that occurs between the suction side pressure during the suction stroke in the suction chamber or compression chamber and the compression side pressure during the compression stroke in the compression chamber. A capacity switching valve is installed so that it can be opened and closed automatically, and by automatically opening and closing this control valve, part of the refrigerant gas is released to the suction chamber when the cooling load decreases.
We are proposing something that adjusts the compression capacity of the compression chamber.

(Problems to be Solved by the Invention) However, in the conventional variable capacity compressor described above, the capacity switching valve is opened and closed based on the pressure difference within the compressor body, so factors other than the cooling load, such as sudden acceleration,
There is a problem in that it is easily affected by pressure fluctuations due to sudden changes in the engine speed and the suction of high-temperature fluid, making it prone to malfunction.

Structure of the Invention (Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a bypass 1ffi! ? &, and an on-off valve is formed in the suction chamber by a valve body that is always biased in a direction to open the bypass passage by a biasing means, and a pressure action chamber provided on the back side of the valve body. Furthermore, in a variable displacement rotary compressor, the suction pipe from the evaporator to the compressor is equipped with a throttle valve to maintain the evaporation pressure of the evaporator above a set value. A spool valve consisting of a large-diameter disk portion and a pair of small-diameter rod portions extending in both directions from the large-diameter disk portion is inserted into an insertion hole consisting of a pair of small-diameter hole portions extending in both directions, and the spool valve is ”
1. Of the pre-throttling pressure chamber and the post-throttling pressure chamber formed below, the post-throttling pressure chamber is communicated with the post-throttling part of the suction pipe, and the pre-throttling pressure chamber is connected to the pre-throttling part of the suction pipe or the atmosphere. and communicate the small diameter hole on the post-throttling pressure chamber side with the pressure action chamber via the pressure guiding passage, and the small diameter hole on the pre-throttling pressure chamber side with the discharge pipe line via the pressure guiding passage, A configuration is adopted in which both the impulse pressure 1ffl paths are communicated, and furthermore, a seal valve that always closes both the small-diameter holes and is selectively pushed open by the small-diameter rod is provided so as to be movable forward and backward.

(Function) By employing the above-mentioned means, the present invention functions as follows.

When the cooling load in the vehicle interior is large, the pressure before and after the throttle in the suction pipe becomes almost the same, so the pressures in the pre-throttling pressure chamber and the post-throttling pressure chamber become balanced.
The seal valve on the side of the discharge pipe is pushed open by the small diameter rod portion of the spool valve, the discharge pipe and the pressure action chamber are communicated with each other, and discharge pressure is sent into the pressure action chamber. As a result, the valve body of the on-off valve closes the bypass passage, and 100% capacity operation is performed.

As the cooling load in the vehicle interior decreases, the pressure before the throttle in the suction pipe decreases, and the pressure difference between before and after the throttle increases, causing the seal valve on the discharge pipe side, which was in the open state, to is closed. Therefore, communication between the pressure chamber and the discharge pipe is cut off, but since both seal valves are closed at this time, the pressure chamber is maintained at the discharge pressure, and the valve body closes the bypass passage. 100% capacity operation is maintained.

Furthermore, when the cooling load in the passenger compartment decreases and the pressure difference between before and after the throttle reaches the set value, the seal valve on the suction pipe side is pushed open by the small diameter rod of the spool valve, so that the pressure difference between the before and after throttle ends. and the pressure action chamber are communicated with each other, and the pressure after throttling is sent into the pressure action chamber. Therefore, the valve body opens the bypass passage and the operation is switched to small capacity operation.

When the small-capacity operation continues and the cooling load increases, the pressure difference between before and after the throttle decreases, and the seal valve on the suction pipe side is accordingly closed. As a result, communication between the pressure chamber and the post-throttle portion of the suction pipe is cut off, but since both seal valves are closed at this time, the pressure chamber is maintained at the post-throttle pressure state, and the valve body is bypassed. Keep aisles open
Small capacity operation is maintained.

(Embodiment) Hereinafter, a first embodiment in which the present invention is embodied in a vane compressor will be explained with reference to FIGS. 1 to 7. A disc-shaped front side plate 2 and a rear side plate 3 are joined together to form an elliptical cylindrical space for accommodating a rotor. A front housing 4 having a suction chamber 5 is provided on the front side of the front side plate 2.
The suction chamber 5 is communicated with an external circuit via a suction port 6 and a suction flange 7. A rear housing 8 is joined to the rear surface of the front side plate 2 so as to surround the outer periphery of the barrier side plate 3 and the cylinder 1, and the rear side of the rear housing 8 has an oil sump chamber 10 at the bottom, which contains the gas in the discharged gas. An oil separation chamber 9 for separating oil is formed, and the intermediate separation chamber 9 communicates with an external circuit via a discharge port 11.

A rotary shaft 2 passes through the center of the front side plate 2 and the rear side plate 3 so as to be able to rotate positively, and as shown in FIG. cylindrical rotor 13 formed in
is accommodated in the cylinder 1 so that its outer circumferential surface is in contact with two minor diameter portions of its inner circumferential surface, thereby forming two crescent-shaped chambers 14. On the circumference of the rotor 13, a plurality of vane grooves 15 (in this example, five grooves are shown) are formed with a required depth over the entire width, and each vane groove 15 is slidably fitted. The tips of the vanes 16 abut against the inner circumferential surface of the cylinder 1, thereby dividing the crescent-shaped chamber 14 into a plurality of compression chambers 17, respectively. The compression chamber 17 includes a communication hole 18 formed through the front side plate 2, a suction passage 19 formed through the cylinder 1, and a suction port formed so as to communicate the suction passage 19 and the compression chamber 17. 20 communicates with the suction chamber 5. Further, the compression chamber 17 communicates with a discharge chamber 22 formed between the outer peripheral surface of the cylinder 1 and the inner peripheral surface of the rear housing 8 via a discharge port 21 provided through the cylinder 1. 22 communicates with the oil separation chamber 9 via a communication hole 23 formed through the rear side plate 3. Note that the discharge port 21 is provided with a discharge valve 24 and a valve holder 25.

At positions corresponding to the symmetrical compression chambers 17 of the front side plate 2, as shown in FIG. The capacitors are perforated so that in the open state, the capacity can be reduced as will be described later.

Accommodation recess 2 formed on the inner wall surface of the front housing 4
7 includes a valve body 2 for opening and closing the bypass passage 26.
A pressure chamber 29 is formed on the back side of the valve body 28. Further, the bypass passage 2 is provided between the valve body 28 and the front side plate 2.
A spring 30 is interposed as a biasing means for biasing 6 in the direction in which it is normally opened (toward the left in FIG. 1). An on-off valve B for the bypass passage 26 is formed by the valve body 28, the pressure action chamber 29, and the spring 3o.

On the other hand, a suction pipe line 31 is communicated with the suction flange 7, and a discharge pipe @32 is communicated with the discharge port 11.

A condenser C1, an expansion valve D1, and an evaporator E are connected in series to the discharge pipe line 32, and the suction pipe line 31 is connected to the evaporator E.
are being communicated.

Further, the suction pipe line 31 is provided with a suction throttle valve F located at an arbitrary intermediate portion thereof. A spool valve 33 is fitted into the suction throttle valve F so as to be movable forward and backward, facing the opening on the side of the evaporator E, and an atmospheric pressure chamber 34 communicating with the atmosphere is provided at one end on the bottom side of the spool valve 33. A spring 35 is interposed in the atmospheric pressure chamber 34, and a suction pressure chamber 36 is provided on the opposite side of the spool valve 33 from the spring 35. The spool valve 33 of the suction throttle valve F moves back and forth in response to changes in the differential pressure generated between the two pressure chambers 34 and 36 to keep the evaporation pressure of the evaporator E constant.

A fitting insertion hole 38 for the spool valve 39 is bored in the valve body 37 of the control valve G, and the fitting insertion hole 38 extends from the large diameter hole 38a along the center line of the large diameter hole 38a. It consists of a pair of small diameter holes 38b drilled in both directions. At both ends of both the small diameter holes 38b, 38b, a boat 40.40 is interposed between them, and holes 4-2.42 for fitting a seal valve 41.41, which will be described later, are formed so as to face each other. .

The spool valve 39 is formed by a large-diameter disk portion 39a and a pair of small-diameter rod portions 39b, 39b extending from the large-diameter disk portion 39a in both directions along its center line, and includes a large-diameter m portion 39a. is fitted into the large-diameter hole 38a, and the small-diameter rod portions 39b, 39b are fitted into the small-diameter holes 38b, 38b so as to be freely retractable. In the large diameter hole 38a of the insertion hole 38, a pre-throttling pressure chamber 43 and a post-throttling pressure chamber 44 with a spring 45 interposed therein are formed on both sides of the large diameter disc part 39a below the "1". This pressure chamber 44 and the post-throttling portion of the suction throttle valve F of the suction pipe line 3 are communicated through a pressure guiding passage 46. Further, a pressure guiding passage 47 is connected to the pre-throttling pressure chamber 43, and its tip portion communicates with an opening in the pre-throttling portion of the suction throttle valve F.

A seal valve 41.4 is provided in both the fitting holes 42, 42 facing the small diameter rod portions 39b, 39b of the spool valve 39.
1 is inserted so that it can move forward and backward.

A spring 48.48 is interposed in both fitting insertion holes 42.42, and both seal valves 41, 4.1 are always connected to small diameter holes 38b, 38b.
is biased in the direction of blocking it. In addition, both the boats 40.
40 are connected to pressure guiding passages 49 and 50, and the pressure guiding passage 49 on the post-throttling pressure chamber 44 side is connected to the pressure acting chamber 29 to the compressor.
It is connected to the.

The other pressure guiding passage 5o is connected to the discharge pipe line 32. In addition, an O-ring 51 is interposed near the base of the small diameter hole 38b of the 43 examples of pre-throttle pressure chambers, and a pressure guiding passage 52 is provided extending from an arbitrary position from the tip. It is connected to the pressure guiding passage 49 on the post-throttle pressure chamber 44 side. The diameter holes 38b and 38b of both vehicles are formed to also serve as a pressure guiding passage, and the small diameter hole 38b of the pre-throttle pressure chamber 43 communicates the boat 40 and the pressure guiding passage 52.

Next, the operation of the vane compressor constructed as described above will be explained.

When the cooling load in the vehicle interior is large, that is, when Q and Do in the graph shown in FIG. 5 are exceeded, the pressure in the evaporator E is high. Therefore, a large pressure difference occurs between the suction throttle pressure Pe of the suction throttle valve F on the evaporator E side and the pressure obtained by adding the biasing force of the spring 35 to the atmospheric pressure in the atmospheric pressure chamber 34, and this pressure The difference causes the spool valve 33 to be in a wide open state, and the post-intake throttling pressure Ps on the suction flange 7 side of the suction pipe 31 and the suction pre-throttling pressure Pe on the evaporator E side become approximately the same pressure state.

The suction pre-throttling pressure Pe enters the pre-throttling pressure chamber 43 of the control valve G via the pressure guiding passage 47, and the suction post-throttling pressure Ps passes through the pressure guiding passage 46 into the post-throttling pressure chamber 4.
As mentioned above, the pressures Pe and Ps before and after the suction throttle are almost the same, so the spool valve 39 is biased by the spring 45 in the direction of opening the seal valve 41, and the small diameter rod part Seal valve 41 by 39b
is pushed open against the biasing force of the spring 48. The seal valve 41 is pushed open and the pressure guiding passage 50 and the pressure guiding passage 52 are brought into communication, and the discharge pressure in the discharge pipe line 32 is reduced to the pressure guiding passage 50.
0, boat 40. Small diameter hole 38b, pressure guiding passage 52.49
It is fed into the pressure action chamber 29 through various parts. Then, the valve body 28 is pressed toward the front side plate 2. That is, as shown in FIG. 1, the discharge pressure acting on the back surface of the valve body 2B is equal to the suction pressure acting on the front surface of the valve body 28 (suction pressure in the compression chamber 17 + biasing force of the spring 30).
, the bypass passage 26 is closed and 100% capacity operation is achieved.

Then, by continuing the 100% capacity operation as described above for a certain period of time, the cooling load in the vehicle interior gradually decreases to a state below Q and ω in the graph shown in FIG. As a result, the pressure in the evaporator E gradually decreases, but when the pressure in the evaporator E decreases in this way, the pre-intake throttle pressure Pa of the suction throttle valve F and the atmospheric pressure in the atmospheric pressure chamber 34 are affected by the spring 35. The pressure difference between the pressure and the pressure added to the biasing force gradually decreases, and the amount of opening of the spool valve 33 gradually decreases. Accordingly, a pressure difference ΔP is generated between the suction throttle pre-throttle pressure Pe and the suction throttle post-throttle pressure Ps in the suction pipe 3I, and the pressure difference ΔP gradually increases. As a result, the spool valve 39 of the control pulp G, which had been biased toward the pre-squeezing pressure chamber 43, gradually retreats toward the post-squeezing pressure chamber 44 against the biasing force of the spring 45. Then, the boat 40, which had been opened by the small diameter rod portion 39b, is closed by the seal valve 41, and the two pressure impulse passages 50, 52 are cut off. In this way, the discharge pipe 3
Even if the seal valve 41 on the second side is closed, the seal valve 41 on the suction pipe 31 is not immediately opened and remains closed for a period of time. When both seal valves 41, 41 are closed, the back side of the valve body 28 is kept in a biased state by the discharge pressure. Therefore, the cooling load in the vehicle interior gradually decreases, and a differential pressure ΔP occurs between the suction throttle pre-throttling pressure Pa and the suction post-throttling pressure Ps in the suction pipe 31.
100% capacity operation is maintained in a state in which Q gradually increases, that is, in a state below Q4oo in the graph shown in FIG.

Then, a state in which the cooling load in the vehicle interior is further reduced and the differential pressure ΔP in the suction pipe 31 exceeds the set value;
That is, in the graph shown in FIG. 5, when the cooling load becomes Qd and the differential pressure ΔP becomes ΔPd, the seal valve 4 on the suction pipe 31 side
1 is pushed open by the small diameter rod portion 39b. and,
When the pressure guiding passage 46 and the pressure action chamber 29 are communicated with each other, the suction throttled pressure Ps in the suction pipe line 31 is reduced to the pressure guiding passage 46,
After throttling, it is fed into the pressure action chamber 29 through the pressure chamber 44, the small diameter hole 38b, the boat 40, and the pressure guiding passage 49. Since the suction throttling pressure Ps becomes lower than the pressure in the compression chamber 17 acting on the front side of the valve body 28, the valve body 28 is moved by the spring 30 in the direction of opening the bypass passage 26.

As shown in FIG. 3, when the bypass passage 26 is opened,
It enters a small capacity operation state.

By switching to small capacity operation, the differential pressure ΔP becomes smaller while the cooling load remains the same. In other words, the differential pressure ΔP decreases from ΔPd to ΔP1 in the graph shown in FIG. 5 while the cooling load remains Qd, and the control valve The G spool valve 39 is again moved toward the pre-throttling pressure chamber 43 by the urging force of the spring 45, and the seal valve 41 on the suction pipe line 31 side is closed as shown in FIG. At this time, both seal valves 41.41
is closed, the pressure chamber 29 is maintained at the suction pressure, and the valve body 28 is maintained apart from the front side plate 2. Then, the cooling load becomes even smaller.

On the other hand, when the cooling load is at its minimum (Qmln) and the air conditioner is operated at a small capacity, the differential pressure ΔP gradually decreases as the cooling load increases, as shown in the graph of Figure 5. When the cooling load increases to Qd0, the differential pressure ΔP between the pressure chambers 43 and 44 is almost O (
ΔPo), the seal valve 41 on the pre-throttling pressure chamber 43 side is pushed open, the discharge pipe line 32 and the pressure guiding passage 49 are brought into communication, and the discharge pressure is sent to the pressure action chamber 29. As shown in the figure, the small capacity operation is switched to 100% capacity operation.

In this case, when switching to 100% capacity operation with the cooling load Qd0, the differential pressure ΔP increases from ΔPo to ΔPu, the spool valve 39 retreats to the post-throttling pressure chamber 44 side, and the spool valve 39 retreats to the pre-throttling pressure chamber 43 side. The seal valve 41 of is closed. and,
Since both seal valves, 11.41, are closed,
The pressure application chamber 29 is maintained at the discharge pressure state, and 100% capacity operation is maintained.

In addition, in the graph of Figure 5, Qloo has a compressed hidden A of 100.
The cooling capacity is Q5o when the compressor is in a small capacity operation state and the suction throttle pressure is Pe - the pressure after the suction throttle is Ps general constant pressure constant pressure o. Front pressure Pe - Post-suction throttling pressure Ps Shows the cooling capacity in a state of general constant pressure and constant pressure o. In addition, the set pressure Peo
indicates the pressure just before the spool valve operates in the closing direction from when it is fully open.

Next, the second embodiment will be explained with reference to FIG. 8. A pre-throttling pressure chamber 43' and a post-throttling pressure chamber 44 are formed on both sides of the large-diameter disk portion 39a of the spool valve 39 of the control valve G. The post-throttling pressure chamber 44 is connected to the suction pipe 31 of the suction throttle valve F through a pressure guiding passage 46, and a spring 45 is interposed in the pre-throttling pressure chamber 43'.
It is in direct communication with the atmosphere via 7'.

In this embodiment, the biasing force of the spring 45 is added to the pressure in the post-throttling pressure chamber 44 of the control valve G, that is, the post-throttling pressure Ps in the suction pipe 31, and the pressure in the pre-throttling pressure chamber 43', that is, atmospheric pressure. As in the first embodiment, it is possible to switch between small capacity operation and 100% capacity operation through a change in the differential pressure ΔP generated between the two pressures.

Next, the third embodiment of this invention is a scroll compressor.
The embodiment will be described with reference to FIGS. 9 and 10. At both ends of the center housing 61, there are front housings 62. A rear housing 63 is integrally provided.

A rotary shaft 64 is rotatably supported on the front housing 62, and an eccentric shaft 65 is connected to the inner end of the rotary shaft 64. A movable scroll member 6 is mounted on the eccentric shaft 65.
6 is mounted so that it can only revolve due to an anti-rotation mechanism.

On the other hand, a fixed scroll member 67 is attached to the inner circumferential surface of the rear housing 63, and both scroll members 66 and 67 are formed on disk-shaped substrates 66a and 67a and their front surfaces, and are always connected to each other at two or more locations. a spiral portion 66b in contact with the
67b. The rear housing 6
A suction chamber 68 and a discharge chamber 69 are defined in the center and the outer circumference of the pump 3, respectively. Further, suction passages 70 are provided in two places through the base plate 67a of the fixed scroll member 67, and a discharge iJl passage 72 is provided through the base plate 67a to communicate the discharge chamber 69 and the compression chamber 71. A valve 73 and a valve holder 74 are attached. Similarly, two bypass passages 75 (or one is possible) are formed in the substrate 67a to communicate the compression chamber 71 and the suction chamber 68, and the on-off valves shown in the first embodiment correspond to both passages 75. B are provided respectively.

In this embodiment, as in the previously described embodiment, the bypass passage 75 in the suction chamber 68 is opened and closed, and the cooling capacity is automatically switched in accordance with the cooling load.

In the first embodiment, a Bosch type variable displacement vane compressor with two bypass passages was described, but the present invention was applied to a yoke type variable displacement vane compressor with only one bypass passage. It's okay.

Effects of the Invention As detailed above, according to the present invention, it is not affected by differential pressure fluctuations between suction pressure and discharge pressure caused by factors other than cooling load, such as sudden acceleration, and is not affected by pressure changes due to cooling load. This has the excellent effect of opening and closing the bypass passage and performing accurate and stable capacity switching control.

[Brief explanation of drawings]

, Fig. 1 to Fig. 7 show a first embodiment embodying the present invention, Fig. 1 is a sectional view of the compressor, suction throttle valve, and control valve incorporated in the refrigeration circuit, and Fig. 2 is a sectional view of each part. is a sectional view taken along the line X-X of the compressor shown in Fig. 1, Fig. 3.4 is a sectional view of each part showing the operating state, Figs. 5 to 7 are graphs showing changes in pressure after suction throttling, and Fig. Figure 8 shows the second embodiment, and is a sectional view of the compressor, suction throttle valve, and control valve incorporated in the refrigeration circuit, and Figure 9 shows the third embodiment, which shows the compressor incorporated in the refrigeration circuit. 10 is a sectional view taken along the line Y--Y of the compressor shown in FIG. 9.

Claims (1)

[Claims] 1. A bypass passage is provided in a partition wall that partitions a compression chamber and a suction chamber of a compressor that rotationally moves a compression chamber to compress and discharge suctioned fluid, and the suction chamber is always provided with a bypass passage by a biasing means. A valve body that is biased in the direction of opening the passage and a pressure chamber provided on the back side of the valve body form an on-off valve, and a suction pipe from the evaporator to the compressor is connected to the evaporator. In a variable capacity rotary compressor equipped with a throttle valve that maintains the evaporation pressure above a set value, in a fitting hole consisting of a large diameter hole and a pair of small diameter holes extending in both directions from the large diameter hole, A spool valve consisting of a large-diameter disc part and a pair of small-diameter rod parts extending in both directions from the large-diameter disc part is inserted into the spool valve. The pressure chamber is communicated with the post-throttling part of the suction pipe, and the pre-throttling pressure chamber is made to communicate with the pre-throttling part of the suction pipe or the atmosphere, and the small diameter hole on the post-throttling pressure chamber side is connected to the The pressure action chamber and the small-diameter hole on the pre-throttling pressure chamber side are communicated with the discharge pipe via the pressure passage, and both pressure passages are communicated with each other, and both of the small-diameter holes are always closed, Further, a capacity control mechanism for a variable capacity rotary compressor is provided with a seal valve that is selectively pushed open by the small diameter rod portion and can be moved back and forth.