JPS6325192B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a compressor for vehicle air conditioning.

FIG. 12 shows a refrigeration cycle of the vapor compression refrigeration method, and the operation of this refrigeration cycle is as follows. That is, high-pressure compressed gas (refrigerant) exiting the compressor 101 is cooled and liquefied in the condenser 102 and then stored in the receiver 103 . The flow rate of the liquefied refrigerant is controlled by the expansion valve 104, and the pressure is lowered to a state where it can easily evaporate, and then it evaporates in the evaporator 105, and the heat of evaporation at this time causes the surrounding environment to be Cools the air (air inside the vehicle). The refrigerant vaporized in the evaporator 105 is then sucked into the compressor 101, and the above operation is repeated thereafter. In the vapor compression refrigeration method that performs such a refrigeration cycle, when the cooling load is small, that is, when the temperature inside the vehicle decreases, the evaporator 1
As the pressure and temperature of the refrigerant in the evaporator 105 decreases, icing may occur on the evaporator 105, resulting in a problem that the performance deteriorates. Therefore,
Conventionally, the following measures have been taken to eliminate such problems.

Clutch cycle method This method detects the temperature of the air after passing through the evaporator and turns the pressure switch 106 on and off, thereby connecting and disconnecting the electromagnetic clutch 107 of the compressor 101 in response to the air temperature. In other words, when the cooling load becomes small, compressor 1
However, in this method, the electromagnetic clutch 107 is used frequently, so the life of the electromagnetic clutch 107 is easily shortened, and when the electromagnetic clutch 107 is connected, the shock There are problems such as poor running feeling.

EPR (Evaporation Pressure Regulator) Cycle Method In this method, an evaporation pressure regulator 108 is installed at the outlet of the evaporator 105, and when the cooling load becomes small, the evaporation pressure regulator 108 throttles the flow rate of refrigerant into the evaporator 105. Adjust the refrigerant pressure to the set pressure (approximately 2
kg/cm ² ). That is, FIG. 13 shows the evaporation pressure regulator 108. When the cooling load is large and the pressure inside the evaporator 105 is relatively high, the throttle valve 110 increases the pressure of the passage hole 109 due to the pressure difference before and after the passage hole 109. Since it is open, the refrigerant coming out of the evaporator 105 flows through the through hole 10.
9 to the compressor 101 side. However, when the cooling load becomes smaller and the pressure inside the evaporator 105 decreases, the spring 111 moves the throttle valve 110 in a direction to close the through hole 109. The pressure inside 105 is controlled so as not to fall below a set value. However, a bypass passage 112 is provided so that the circuit is not completely cut off even when the throttle valve 110 is closed, and a small amount of refrigerant flows.

However, in the case of the above method, the evaporation pressure regulator 1
Since the flow rate of the refrigerant is only restricted by 08, the refrigerant is flowing, albeit slightly. Therefore,
The refrigerant flowing from the evaporation pressure regulator 108 to the compressor 101 has a very low pressure and temperature.
From the evaporator pressure regulator 108 near 05 to the compressor 1
01, and when flowing through the suction passage in the compressor 101, it easily receives heat, and the degree of superheating increases. That is, the refrigerant sucked into the compression chamber of the compressor 101 has a very high degree of superheat. As a result, the discharge temperature increases, and at the same time, the compressor temperature also increases, making it easy to cause seizure, and the temperature difference between the suction side and the discharge side of the compressor 101 becomes extremely large, causing problems such as distortion. There is.

The present invention provides a novel compressor that can change its capacity depending on the size of the cooling load and can prevent the pressure and temperature of the refrigerant in the evaporator from decreasing especially when the cooling load is small. This is an attempt to eliminate the problems of the conventional method.

Hereinafter, illustrated embodiments embodying the present invention will be described in detail. First, a first embodiment implemented in a vane type compressor will be described with reference to FIGS. 1 to 5. In the diagram, 1F is the front housing, 1C
indicates the center housing, and 1R indicates the rear housing. 2F and 2R are disk-shaped front and rear end plates, and both end plates 2F and 2R are in close contact with the end surface of the center housing 1C, and their boss portions are inside the front housing 1F and rear housing 1R. is rotatably supported via a bearing 3, and
It is fitted onto a drive shaft 4 inserted through the housing at a position appropriately eccentric from the center of the housing. In a circular space surrounded by the center housing 1C and both end plates 2F and 2R, a hollow cylindrical rotor 5 is mounted against the housing so that a part of its outer circumference is in contact with a part of the inner circumference of the center housing 1C. The rotor 5 is housed eccentrically (the end plate and the drive shaft are concentric), and the outer peripheral surface of the rotor 5 and the center housing 1
A space surrounded by the inner peripheral surface of C and both end plates 2F and 2R is a compression chamber 6 for refrigerant gas.
Note that the rotor 5 is fixed to the end plates 2F and 2R with through bolts (not shown).

In this embodiment, four vanes 7 are provided on the rotor 5 in a radial and slidable manner at equal intervals, and each vane 7 has an outer end that is in close contact with the inner circumferential surface of the center housing 1C. The inner end portion is elastically supported by an elastic ring 8 housed in the cylindrical hole 5a of the rotor 5. 9 is a low pressure chamber surrounded by the front housing 1F and the front end plate 2F; 10 is a low pressure chamber surrounded by the rear housing 1R and the rear end plate 2R;
Both low pressure chambers 9 and 10 are located in the center housing 1, respectively.
It communicates with a suction chamber 12 formed in the shape of C and having a suction hole 11 for return refrigerant through a communication hole 13 . Further, the suction chamber 12 includes the compression chamber 6 and the suction port 1.
4. 15 indicates a discharge valve, and 16 indicates a discharge hole. Note that the blow-by gas in the compression chamber 6 flows out into the cylindrical hole 5a of the rotor 5 through the sliding surface of the vane 7 as shown by the arrow in the figure, and then flows into one of the fitting surfaces of the end plates 2F and 2R with the drive shaft 4. Flows into the front and rear low pressure chambers 9, 10 through the passage groove 17 formed in the
Furthermore, after that, it passes through the communication hole 13 to the suction chamber 12.
Therefore, the pressures in the low pressure chambers 9, 10 and the suction chamber 13 are almost equal.

18, a part of the refrigerant gas in the compression chamber 6 is transferred to the suction chamber 1.
This is a relief passage provided in the center housing 1C in order to enable the air to escape to the center housing 1C, and is provided near the start point of the compression stroke. Escape passage 18
A circular horizontal hole 19 is provided to communicate between the low pressure chambers 9 and 10 on the front side and the rear side, and a relief hole 20 that communicates the horizontal hole 19 with the compression chamber 6;
It consists of a through hole 21 that communicates the horizontal hole 19 with the suction chamber 13, and the relief hole 20 and the through hole 21 are arranged on the same line. In the horizontal hole 19 of the relief passage 18, there is a suction pressure regulator 22 for changing the capacity of the compressor, in other words, the cooling capacity, by opening and closing the passage 18 according to the cooling load.
is included. That is, the suction pressure regulator 22 has a screw 23 at one end, and a telescopic bellows 24 fixed to the center housing 1C by the screw 23, and a bellows 24 that is slidably fitted into the horizontal hole 19 and has a screw 23 at one end. It is composed of a spool 25 which is in contact with or fixed to the other end and whose other end faces the rear low pressure chamber 10, and the suction pressure, that is, the pressure in the low pressure chamber 10, is set to the set pressure (approximately 2 kg /cm ² ), the spool 25 contracts the bellows 24 and moves to the left in the figure, closing the relief hole 20 and the through hole 21 with its large diameter portion 25a, and the suction pressure reaches the set pressure. In the following cases, the bellows 24 moves to the right in the figure due to its extension, and the small diameter portion 25b opens the relief hole 2.
0 and the through hole 21 are set to be open. In addition, as a means for expanding the bellows 24, gas at a constant pressure may be sealed in the bellows 24, or the bellows itself may be given a restoring force and the inside thereof may be vacuumed. Further, the extension force of the bellows 24 relative to the suction pressure can be easily adjusted by adjusting the screwing amount of the screw 23. The amount of movement of the spool 25 is regulated by a sleeve 26a interposed between the screw 23 and the spool 25, and a stopper 26b provided at the end of the horizontal hole 19.

This embodiment is configured as described above,
The effect will be explained below. When the end plates 2F, 2R, rotor 5, and vane 7 are rotated together with the drive shaft 4, the refrigerant gas that has returned to the suction chamber 12 from the evaporator 105 is sucked into the compression chamber 6 through the suction port 14, and is sucked into the compression chamber 6 by the vane 7. It is compressed and sent out from the discharge hole 16 to the condenser 102 side as a high-pressure compressed gas.

In this case, when the cooling load is large and the suction pressure is equal to or higher than the set pressure, the pressure inside the low pressure chamber 10 is also higher than the set pressure, so the spool 25 closes the relief hole 20 and the through hole 21 as described above. The compressor is then operated normally and fully utilizes its capacity.

However, when the cooling load decreases and the suction pressure decreases to below the set pressure,
Since the pressure inside the low pressure chamber 10 also drops below the set pressure, the bellows 24 expands and the spool 25 moves to the right in the figure, opening the relief hole 20 and the through hole 21 (see FIGS. 4 and 5). . Therefore, the compression chamber 6 and the suction chamber 12 are communicated with each other, and a portion of the refrigerant gas in the compression chamber 6 escapes to the suction chamber 12 at an early stage of the compression stroke. Therefore, the capacity of the compressor decreases, the amount of refrigerant gas sucked from the evaporator 105 side decreases, and a drop in suction pressure is prevented.

That is, in the compressor of this embodiment, the compression chamber 6 and the suction chamber 12 are communicated through the relief passage 18, and the communication 18 is opened and closed according to the magnitude of the suction pressure by the suction pressure regulator 22, thereby providing cooling. The capacity of the compressor is changed according to the load to prevent the suction pressure from dropping more than necessary, and the opening degree of the relief hole 20 is adjusted to prevent the suction pressure from falling significantly below the set pressure when the cooling load is small. It will be automatically balanced so that it does not.

In addition, in the above-mentioned embodiment, the end plate 2F,
Although a vane compressor in which the 2R and rotor 5 are integrally formed has been described, it is of course applicable to a separate type.

Next, we will discuss a second example in which the present invention is implemented in a swash plate compressor.
Examples will be described with reference to FIGS. 6 to 9. First, to briefly explain the swash plate compressor, 31 and 31 in the figure are front side and rear side cylinder blocks, and the outer ends of both cylinder blocks 31 and 31 have suction chambers 3 and 31, respectively.
2, 32 and discharge chambers 33, 33 are connected to valve plates 35, 3.
It is attached via 5. The cylinder blocks 31, 31 are arranged at equal intervals in the circumferential direction.
cylinder bore 36 and this cylinder bore 36
It has a suction passage 37, a discharge passage 38, and an oil reservoir chamber 39 formed therebetween, and although not shown, the suction passage 37 communicates with the suction chambers 32, 32, and the discharge passage 38 communicates with the discharge chambers 33, 33. The oil reservoir chamber 39 is also communicated with the suction chambers 32, 32 through a hole 40. A piston 41 is slidably fitted into each of the cylinder bores 36, and each piston 41 is connected to a drive shaft 4 that passes through the center of the cylinder blocks 31, 31 and is supported by bearings 42, 42.
The ball 4 is attached to the swash plate 44 attached to the
5, 45 and shoes 46, 46, and as the swash plate 44 rotates, the cylinder bore 3
It moves back and forth within 6. Note that 47 and 47 are suction ports, and 48 and 48 are discharge ports.

In the swash plate compressor configured as above,
Shaft support portion 31 of cylinder blocks 31, 31
a, 31a, a part of the refrigerant gas in the compression chamber (in this embodiment, the compression stroke side of the cylinder bore 36) is transferred to the suction chamber (in this embodiment, the suction stroke side of the cylinder bore 36, the oil reservoir chamber 39, and the swash plate chamber). Escape passages 50, 50 are provided to allow the air to escape to the low pressure side (e.g., 49). This escape passage 5
0 and 50 are horizontal holes 5 of appropriate sizes formed in the fitting surfaces of the cylinder blocks 31 and 31 with the drive shaft 43 at the front and back positions sandwiching the swash plate 44, respectively.
1, 51, relief holes 52, 52 that connect both the horizontal holes 51, 51 to the cylinder bore 36, and a through hole 5 that connects both the horizontal holes 51, 51 to the oil reservoir chamber 39.
3 and 53, and the relief holes 52 and 52 communicate with the swash plate chamber 49 when the piston 41 is in the top position. Note that the swash plate chamber 49 is communicated with the oil reservoir chamber 39 through an oil guide hole 54. Therefore, in the horizontal holes 51, 51 in the relief passages 50, 50,
As in the first embodiment described above, the relief passages 50, 5
suction pressure regulators 57, 5 consisting of bellows 55, 55 and spools 56, 56 for opening and closing 0;
7 is incorporated, and the spools 56, 56 receive the pressure of the suction chambers 32, 32 on their end faces through the gap between the fitting surfaces of the cylinder blocks 31, 31 and the drive shaft 43. However, in this embodiment, the spools 56, 56 are formed in an annular shape, and the amount of movement thereof is determined by the amount of movement of the sleeve 56, which is interposed between the screws 58, 58 of the bellows 55, 55 and the spools 56, 56.
9, 59 and stoppers 60, 60 integrally formed on the cylinder blocks 31, 31.

This embodiment is configured as described above,
Therefore, when the cooling load is large and the pressure inside the suction chambers 32, 32, that is, the suction pressure is higher than the set pressure,
Due to the pressure, the spools 56, 56 compress and move the bellows 55, 55, respectively, and close the relief holes 52, 52 and the through holes 53, 53 with their large diameter portions 56a, 56a, as shown in FIG. Therefore, the compressor is operated normally and its capacity is fully demonstrated.

However, when the cooling load decreases and the suction pressure drops below the set pressure, the bellows 55, 55 expand to overcome the pressure, and the spools 56, 56 move accordingly, reducing their diameter as shown in FIG. Relief holes 52, 52 by portions 56b, 56b
and open the through holes 53, 53. As a result, the relief holes 52, 52 and the through holes 53, 53 communicate with each other on the front side and the rear side, respectively, but in this case, the respective positional relationships of the pistons 41 within the three cylinder bores 66 are as follows. When one is in the top position, the other one is in the compression stroke and the other one is in the suction stroke, so one of the relief holes 52, 52 on the front side and the rear side, respectively, is in the cylinder bore 36A in the compression stroke. The other one communicates with the cylinder bore 36B of the suction stroke, and the other one communicates with the swash plate chamber 4.
It will lead to 9. Therefore, as shown by the arrow in FIG. 7, the cylinder bore 36 during the compression stroke
A portion of the refrigerant gas in A escapes into the cylinder bore 36B in the suction stroke, the swash plate chamber 49, and into the oil reservoir chamber 39, thereby reducing the capacity of the compressor and preventing a drop in suction pressure.

Next, a third embodiment in which the present invention is applied to a crank type compressor will be described with reference to FIGS. 10 and 11. This embodiment shows a vertical two-cylinder cylinder, and the upper end surface of the cylinder block 61 (or crankcase) has a suction chamber 62 and a discharge chamber 6.
3 is fixed via a valve plate 65, and a piston 67 fitted into a cylinder bore 66 formed in the cylinder block 61 so as to be movable up and down is connected to a connecting rod 69 by rotation of a crankshaft 68. is reciprocated through the A suction chamber 70 is formed in the cylinder block 61 so as to surround the cylinder bore 66, and this suction chamber 70 communicates with the suction chamber 62 of the cylinder housing 64 through a hole 71. 72 is a suction port that connects the suction chamber 62 and the cylinder bore 66, and 73 is a discharge port that connects the discharge chamber 63 and the cylinder bore 66.

In the crank type compressor configured as described above, a portion between the bores in the cylinder block 61 is provided to allow a portion of the refrigerant gas in the cylinder bore 66 to escape to the suction chamber side during the compression stroke. A relief passage 74 is provided, and this relief passage 74 includes a vertical hole 75 that vertically penetrates the cylinder block 61, a relief hole 76 that communicates the vertical hole 75 with both cylinder bores 66, and a vertical hole 7.
5 and a through hole 77 that communicates with the suction chamber 70. In the vertical hole 75, a suction pressure regulator 80 consisting of a bellows 78 and a spool 79 for opening and closing the relief passage 74 according to the suction pressure is incorporated, similar to the embodiment described above. receives the pressure of the suction chamber 62 through a hole 81 in its upper surface. The amount of movement of the spool 79 is regulated by a sleeve 83 interposed between the spool 79 and a screw 82 fixing the bellows 78, and a sleeve 84 fitted into the upper part of the vertical hole 75.

This embodiment is configured as described above,
Therefore, when the cooling load is large and the suction pressure in the suction chambers 62, 70 is higher than the set pressure, the bellows 78 is compressed by the pressure as shown in the figure, and the large diameter portion 79a of the spool 79 closes the relief holes 76 and 78. Since the through hole 77 is closed, the compressor operates normally and exhibits sufficient capacity.

However, as the cooling load becomes smaller, the suction chamber 6
When the suction pressure inside 2, 70 falls below the set pressure, the bellows 78 overcomes the suction pressure and expands, and accordingly the spool 79 moves upward from the illustrated state and its small diameter portion 79a closes the relief hole 76 and Since the through hole 77 is open, a portion of the refrigerant gas in the cylinder bore 66 during the compression stroke escapes into the suction chamber 70 or into the other cylinder bore 66 during the suction stroke, which reduces the capacity of the compressor. A drop in suction pressure is prevented.

In each of the above-mentioned examples, the degree of decrease in compressor capacity when the cooling load decreases is as follows:
It depends on where the relief holes 20, 52, 76 are selected, and the closer they are to the top of the cylinder bore, the greater the capacity can be reduced, but the closer they are to the top, the higher the pressure in the relief passages 18, 50, 74. Due to this, sufficient care must be taken in selecting the positions of the relief holes 20, 52, and 76, since gas leakage is likely to occur during normal operation. Also,
Instead of escaping from the relief holes 20, 52, 76 to the suction chamber side, the refrigerant gas may be configured to bypass other parts and flow to the suction chamber without directly reaching the end surfaces of the spools 25, 56, 79. Desirably, this makes it possible to reduce pressure fluctuations (pulsations) acting on the end faces of the spools 25, 56, 79.

As described in detail above, the present invention communicates a compression chamber and a suction chamber through a refrigerant gas relief passage, and uses a suction pressure regulator built into this relief passage to ensure that the suction pressure is equal to or higher than a set pressure. The relief passage is sometimes closed, and when the suction pressure is lower than the set pressure, the relief passage is opened to release a part of the refrigerant gas in the compression chamber to the suction chamber. Therefore, according to the present invention, the cooling load is reduced. Since the capacity of the compressor can be automatically changed according to The frequency of use of the refrigerant is greatly reduced, extending its lifespan, and the high superheat state caused by the low pressure and temperature of the refrigerant gas between the evaporator and the suction chamber of the compressor can be prevented. This has the effect of preventing seizure and distortion caused by abnormal overheating of the compressor, which occurs in the EPR cycle system.

Furthermore, since the present invention is a system in which the compressed gas in the process of being compressed in the compression chamber is released to the suction chamber, it is possible to reduce power loss and to Decrease in efficiency can be prevented.

Further, the present invention provides a suction pressure regulator configured to open and close the passage by sliding a spool using an elastic member and suction pressure in the relief passage,
In other words, the suction pressure regulator itself directly detects the cooling load and opens and closes the passage, which simplifies the structure compared to a system in which the cooling load detection means and passage opening/closing means are configured separately. This will greatly help reduce costs.

[Brief explanation of the drawing]

FIG. 1 is a front cross-sectional view of a vane compressor showing a first embodiment of the present invention, and FIG. 2 is an A--
3 is a sectional view taken along the line A-B in FIG. 1, FIG. 4 is a front sectional view showing when the relief passage is open, and FIG. 5 is a side sectional view showing the same when the relief passage is open. , FIG. 6 is a side sectional view of a swash plate type compressor showing a second embodiment of the present invention, FIG. 7 is a front sectional view of the same swash plate type compressor (however, the piston is omitted), and FIGS. 8 and 9. The figure is an enlarged sectional view showing the main parts (however, the drive shaft is omitted), FIG. 10 is a longitudinal sectional view of a crank type compressor showing a third embodiment of the present invention, and FIG. 11 is a C-- 12 is an explanatory diagram showing a refrigeration cycle of vapor compression refrigeration method, and FIG. 13 is a sectional view showing an evaporation pressure regulator. 6... Compression chamber, 9, 10... Low pressure chamber, 12...
Suction chamber, 18, 50, 74... Relief passage, 19,
51...Horizontal hole, 75...Vertical hole, 20, 52, 76
...Escape hole, 21,53,77...Through hole, 22,
57, 80... Suction pressure regulator, 24, 55, 7
8... Bellows, 25, 56, 79... Spool, 36... Cylinder bore, 39... Oil sump chamber, 4
9... Swash plate chamber, 62, 70... Suction chamber, 66...
cylinder bore.

Claims (1)

[Claims] 1. The compression chamber and the suction chamber are communicated by a relief passage that allows part of the refrigerant gas in the compression chamber to escape to the suction chamber during the compression stroke, and this relief passage includes a passageway for opening and closing. A suction pressure regulator is provided, which consists of a sliding spool and an elastic member that always presses the spool toward the passage open side, and when the cooling load is large and the suction pressure exceeds a set pressure, the suction pressure moves the spool. The compressor changes the compression capacity by moving the spool using the elastic member and opening the relief passage when the cooling load is small and the suction pressure falls below the set pressure.