JPS63140877A - Vane back pressure applying device for sliding vane type compressor - Google Patents

Abstract

PURPOSE:To prevent the malfunction phenomenon of a vane by communicating or shutting a gas passage communicating a vane back pressure chamber and a high-pressure case with a sliding body energized by a spring. CONSTITUTION:A sliding body 35 is provided in a sliding chamber 33 opened to a high-pressure chamber 14 to one end and communicated to the intake side portion of a working chamber 8 via a passage 34. When the pressure difference between the high-pressure side and the low-pressure side becomes small, the sliding body 35 is separated from a valve seat 36 against a spring 37. A gassy fluid is fed into a vane back pressure chamber 17 from a high-pressure chamber 14 via gas passages 26, 27. Accordingly, the malfunction phenomenon of a vane can be prevented effectively.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a vane backpressure applying device used in a sliding vane compressor used in automobile air conditioners and the like.

As is well known in the art, in a sliding vane compressor, high-pressure lubricating oil is applied to the rear end of the vane by a pressure difference so that the vane rotates and slides with the tip of the vane in contact with the inner wall of the cylinder as the rotor rotates. feeding structures are widely used.

An example of a vane back pressure applying device for the above-mentioned conventional sliding vane compressor will be described below with reference to the drawings.

4 to 6 show the specific structure of a sliding vane compressor having a conventional differential pressure oil supply type vane back pressure applying device. In the figure, 1 is a cylinder having a cylindrical inner wall, 2 is a rotor whose outer periphery partially forms a minute gap with the inner wall of the cylinder 1, 3 is a plurality of vane slots provided in the rotor 2, and 4 is inside the vane slot 4. 5 is a drive shaft formed integrally with the rotor 2 and rotatably supported; 6 and 7 respectively close both ends of the cylinder 1 to form a working chamber 8 therein; The front side plate and the rear side plate form the front side plate and the rear side plate.

9 is a suction port that communicates with the working chamber 8 on the low pressure side, 1o is a discharge port that communicates with the working chamber 8 on the high pressure side, 11 is a discharge valve disposed at the discharge port, and 12 is a high pressure chamber that communicates with the high pressure passage 13. This is a high-pressure case provided with a screen 15 that separates and captures lubricating oil in the compressed high-pressure fluid. Reference numeral 16 denotes a vane back pressure applying device body disposed on the rear side plate 7, which supplies lubricating oil from an oil reservoir below the high pressure chamber 14 to the vane back pressure chamber 17. 18 is an oil supply passage that communicates the oil reservoir below the high pressure chamber 14 and the vane back pressure chamber 17, 19 is a passage that limits the amount of oil supply due to differential pressure, 2o is a ball seat provided in the middle of the oil supply passage 18, and 21 is a A sphere that contacts or separates from the ball seat 2o to interrupt communication with the oil supply passage 18, 22 is a plunger chamber that opens into the ball seat 20, and 23 is slidably disposed inside the plunger chamber 22 and moves toward the ball seat 20. When the sphere 21 is the sphere 2
The plunger 24 is a pressure introduction path that communicates the lower plunger chamber 25 at the lower end of the plunger with the working chamber 8 immediately in front of the discharge valve 11.

The operation of the vane back pressure applying device for a sliding vane compressor configured as described above will be described below.

When the drive shaft 5 and rotor 2 rotate clockwise in FIG. 5 due to power transmission from a drive source such as an engine,
Accordingly, low pressure fluid flows into the working chamber 8 from the suction port 9. The high-pressure fluid compressed as the rotor 2 rotates pushes up the discharge valve 11 from the discharge port 1o, flows into the high-pressure chamber 14 through the high-pressure passage 13, and the lubricating oil is separated and captured by the screen 15. On the other hand, from the pressure introduction path 24, the overcompressed gas in the working chamber 8, which has enough pressure to overcome the pressure of the high-pressure fluid and push up the discharge valve 11, flows into the lower plunger chamber 25.
The plunger 23 moves toward the spherical seat 20 and releases the spherical body 21 from the spherical seat 2o. Therefore, the oil supply passage 18 is communicated with the lubricating oil separated from the high pressure fluid and stored below the high pressure chamber 14, and is supplied from the passage 19 and the oil supply passage 18 to the vane back pressure chamber 17 due to the differential pressure, and the It is subjected to suppression and flows into the working chamber 8 through the gap between the rotor 2 and the front side plate 6 and rear side plate 7. Furthermore, when the compressor stops, the pressure in the working chamber 8 rapidly drops to the pressure of the low-pressure side fluid, so the pressure in the lower plunger chamber 25 also drops to the pressure of the low-pressure side fluid, and the pressure at the lower end of the plunger 23 decreases. Since the pressure at the upper end of the plunger 23 is smaller than the pressure at the upper end of the plunger 23, the plunger 23
Move to the side. Therefore, the sphere 21 comes into contact with the sphere seat 20, and the oil supply passage 18 is blocked. Therefore, since no more lubricating oil is supplied, it is possible to prevent the liquid from being compressed when the compressor is started due to lubricating oil remaining in the working chamber 8.

Problems to be Solved by the Invention However, in the conventional vane backpressure applying device described above, the pressure of the fluid on the low-pressure side and the pressure of the fluid on the high-pressure side become equal, such as when a certain period of time has passed after the compressor has stopped. When the compressor is started in this condition, the vanes 4 rotate as the rotor 2 rotates, and even if the vane 4 attempts to extend and retract into the vane slot a, there is no differential pressure to supply lubricating oil, the water head of the lubricating oil, Since the resistance at the beginning of the flow due to viscosity and inertia is large, as a result, a sufficient amount of lubricating oil cannot be supplied to cope with the volume fluctuation of the vane back pressure chamber 17 that occurs when the vane 4 expands and retracts. For this reason, especially when the rotational speed at the time of starting the compressor is low, the pressure in the vane back pressure chamber 17 decreases, causing the well-known malfunction phenomenon in which the vane 4 separates from the inner wall of the cylinder 1 and collides with it again, and the compression failure phenomenon in which the fluid is not compressed. There was a problem.

In addition, expanding the passage area of the passage 19 in order to secure the amount of lubricating oil means that the vane 4 is moved excessively to the cylinder 1 during steady operation.
This causes increased wear on the tip of the vane 4 and the inner wall of the cylinder 1 and increases input to the compressor, which deteriorates the durability and efficiency of the compressor. There was a problem in that centrifugal force further aggravated this tendency.

In view of the above-mentioned problems, the present invention is capable of preventing vane malfunction or poor compression even when the compressor is started at low speed when there is no or small pressure difference between the high and low pressures of the compressor, and does not impair durability or efficiency. A vane back pressure applying device for a sliding vane compressor is provided.

Means for Solving the Problems In order to solve the above problems, the vane back pressure applying device for a sliding vane compressor of the present invention has a gas passage communicating between the vane back pressure chamber and the high pressure case, and a high pressure case at one end. A sliding body is provided at the other end of the sliding body that receives the pressure inside the case and moves under the pressure lower than the pressure inside the high-pressure case and the biasing force of a spring during steady operation to communicate and cut off the gas passage.

With the above configuration, the present invention has the above-mentioned configuration, so that even when the compressor is started with no or a small pressure difference, the sliding body moves by the biasing force of the spring and communicates the gas passage, so the rotation of the rotor is prevented. Gaseous fluid can be instantly supplied from the gas passage to respond to volume fluctuations in the vane back pressure chamber that occur when the vane rotates and expands and retracts into the vane slot. Therefore, since no pressure drop occurs in the vane back pressure chamber, it is possible to prevent vane malfunction and compression failure. In addition, when the pressure in the high pressure chamber increases after startup, the sliding body moves and blocks the gas passage, so the appropriate amount of lubricating oil is supplied to the vane back pressure chamber from the oil supply passage, without compromising durability or efficiency. .

Embodiment Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 3 of the accompanying drawings.

1 and 2 show a first embodiment of the present invention, and in the figures, parts having the same functions and effects as the vane back pressure applying device of the conventional sliding vane compressor are the same. The description will be omitted by writing the symbol.

In the figure, 26 is a first gas passage communicating with the oil supply passage 18, 27 is a second gas passage communicating with the high pressure chamber 14, and 33 is a second gas passage communicating with the high pressure chamber 14.
is a sliding chamber whose one end is open to the high pressure chamber 14 and whose other end is connected to the suction side portion of the working chamber 8 through a passage 34; 35 is a sliding body slidably disposed within the sliding chamber a3; 36 is the sliding body 3
A valve seat 37 blocks the first gas passage 26 and the second gas passage 27 only when the valve seat 5 is in contact with the valve seat 37, and a spring 37 urges the sliding body 35 in a direction away from the valve seat 36.

The operation of the vane backpressure applying device for a sliding vane compressor configured as described above will be described below.

When the compressor stops, the pressure within the working chamber 8 drops rapidly and the pressure at the lower end of the plunger 23 also drops.

Therefore, the plunger 23 moves toward the lower plunger chamber 25 and comes into contact with the sphere 20, so that the oil supply passage 18 is blocked, as in the conventional vane backpressure applying device.

On the other hand, while the pressure in the high pressure chamber 14 is high, the sliding body 35 remains in contact with the valve seat 36, but when a certain period of time passes after the compressor stops, the pressure difference between the high pressure side and the low pressure side becomes small. The sliding body 35 is released from the valve seat 36 by the biasing force of the spring 37. As a result, the first gas passage 26 and the second gas passage 27 are brought into communication.

Next, a case will be described in which the compressor is started when there is no pressure difference between the high pressure side and the low pressure side. When the vane 4 rotates with the rotation of the rotor 2 and expands and retracts inside the vane slot 3, the pressure inside the vane back pressure chamber 17 decreases due to volume fluctuations in the vane back pressure chamber 17.
Since the gaseous fluid is instantaneously supplied to the vane back pressure chamber 17 via the second gas passage 27 and the first gas passage 26, a pressure drop in the vane back pressure chamber 17 can be prevented.

Further, after starting, the pressure in the high pressure chamber 14 that the finger body 35 receives increases, and the pressure in the suction side portion of the working chamber 8 increases.
When the urging force is overcome, the sliding body 35 comes into contact with the valve seat 36, so that an appropriate amount of lubricating oil can be supplied to the vane back pressure chamber 17 from the oil supply passage 18 in the same manner as in the conventional vane back pressure applying device.

As described above, according to this embodiment, the oil supply passage that communicates with the vane back pressure chamber and the first and second gas passages that communicate with the high pressure chamber, the pressure of the high pressure chamber at one end, and the suction of the working chamber at the other end. By providing a sliding body that receives pressure from the side portions and a spring that biases the sliding body in the direction of communicating the first and second gas passages, even when the compressor is started from a high and low pressure equalized state, it can be used immediately after starting. The pressure drop in the vane backpressure chamber that occurs in the vane can be prevented by supplying gaseous fluid from the first and second gas supply passages to exert the necessary suppression on the expansion of the vane.
Vane malfunctions and compression failures can be prevented. Furthermore, since an appropriate amount of lubricating oil can be supplied to the vane back pressure chamber even during normal operation, durability and efficiency are not compromised.

FIG. 3 shows a second embodiment of the present invention, and in this figure, the same reference numerals as in FIGS. 1 and 2 showing the first embodiment have the same functions and effects. It is something.

The difference from the first embodiment is that the valve seat 36 is disposed on the side of the sliding chamber 33 that communicates with the high pressure chamber 14, and the sliding chamber 33 communicates with the high pressure chamber 14 via a second gas passage 27. When the sliding body 35 is in contact with the valve seat 36, the pressure in the oil supply passage 18 is introduced into the sliding chamber 33 on the communication side of the high pressure chamber 14 via the first gas passage 26. However, when the pressure difference between the high and low pressures becomes smaller after the compressor is stopped, the first gas passage 26 and the second gas passage 27 are brought into communication by the urging force of the spring 37, and when the compressor is started, the second gas passage 27 is connected to the vane back pressure chamber. The gaseous fluid in the high pressure chamber 14 can be supplied to the vane back pressure chamber, and after startup, the pressure in the high pressure chamber 14 increases and the sliding body 35 comes into contact with the valve seat 36, so that an appropriate amount of lubricating oil is supplied to the vane back pressure chamber. Because we can supply
It is clear that this embodiment has the same effect as the first embodiment.

Note that in the first and second embodiments, the first gas supply passage 26 is communicated with the oil supply passage 18, but the first gas supply passage 26 may be communicated with the vane back pressure chamber 17 independently of the oil supply passage 18. good. Furthermore, in these two embodiments, the sliding vane type compressor is of a perfect circular type having only one suction port 9 and one discharge port 10, but it may be of a type having a plurality of suction ports 9 and multiple discharge ports 10. Although the number of vanes shown is four, any number of vanes may be used.

Further, in the first and second '15 examples, the passage 34 opens to the suction side portion of the working chamber 8, but the sliding body 35 receives the pressure in the high pressure chamber 14 at one end in the steady operating state of the compressor. If the combination has a pressure difference sufficient to overcome the biasing force of the spring 37 and the pressure introduced by the passage 34 and come into contact with the valve seat 36, it will be possible to receive the pressure not only in the compressor but also in any part of the refrigeration cycle. It may be configured as follows.

Effects of the Invention As described above, the present invention can reduce the pressure drop at the back of the vane that occurs immediately after starting even when the compressor is started when there is no or small pressure difference between the high and low pressures of the compressor. In addition, under steady operating conditions, the appropriate amount of lubricating oil can be supplied to the back of the vane by shutting off the gas passage. It is possible to prevent defective phenomena.

[Brief explanation of the drawing]

FIG. 1 is an enlarged cross-sectional view of essential parts of a vane back pressure applying device according to a first embodiment of the present invention, and FIG. 2 is a sliding vane type compressor equipped with a vane back pressure applying device according to a first embodiment of the present invention. 3 is an enlarged sectional view of the main part of the vane back pressure applying device in the second embodiment of the present invention, and FIG. 4 is a sectional view of the machine.
The figure is a longitudinal sectional view of a sliding vane compressor equipped with a conventional vane back pressure applying device, and Figure 5 is taken along the line X-X in Figure 4.
FIG. 6 is an enlarged sectional view of essential parts of a conventional vane back pressure applying device. 14...High pressure chamber, 17...Bain back pressure chamber, 18...Refueling passage, 26...First gas passage, 27...Mark・Second gas passage, 35...
...Sliding body, 37... Spring. Name of agent: Patent attorney Toshio Nakao Haga 1/4
- Takashi's room lε - Initial soak 26 - 1st case passage 27 - - 2nd force application 3s - Sliding body 4 - Hehn Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 f3

Claims (1)

[Claims] A cylinder having a cylindrical inner wall, a rotor that rotates eccentrically within the cylinder and has a vane slot, a vane that is slidably inserted into the vane slot, and a working chamber that is closed at both ends of the cylinder. a side plate forming a suction port and a discharge port opening into the working chamber; a discharge valve provided at the discharge port; a high-pressure case communicating with the discharge port and having an oil reservoir portion at a lower portion; an oil supply passage that communicates a vane back pressure chamber formed by a slot and the end of the vane with the oil reservoir; an oil passage opening/closing means for disconnecting communication between the oil supply passage; and the high pressure case and the vane back pressure chamber. and a gas passage that communicates with the high pressure case at one end and moves under pressure lower than the pressure inside the high pressure case and the biasing force of a spring during steady operation at the other end to communicate and cut off the gas passage. A vane back pressure application device for a sliding vane compressor, which is equipped with a sliding body that