JPS60142082A - Suction counterflow preventing device in vane type rotary compressor - Google Patents

Abstract

PURPOSE:To aim at preventing inferior compression upon starting in a low rotational speed range, by providing such an arrangement that a valve member is abutted against a valve seat under the urging force of a spring when a difference in pressure of a compressor is small so that a suction port is maintained to be blocked to surely press a vane against the inner wall of a cylinder. CONSTITUTION:When a compressor is started in such a condition that a difference in pressure of the compressor is zero or low since the compressor is rested for a long time, the pressure in a space 30 becomes equal to the pressure in a suction passage 19. Accordingly, a valve element 23 is abutted against a valve seat 22 under the resilient force of a spring 29 to hold the blocking of the suction passage 19. Therefore, the pressure in a suction side working chamber 8 lowers due to increase in the volume of the working chamber 8 accompanied with rotation of a vane 3 so that a force acting upon the tip end of the vane 3 to introduce the vane 3 into a vane slot 4 become remarkably small. As a result, the vane 3 is pressed against the inner wall of a cylinder 1 so that bad affection of the vane may be prevented to sustain normal operation.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a suction backflow prevention device for a vane rotary compressor used in automobile air conditioners and the like.

The structure of the conventional example and the in-between (Sk points) As is well known, in vane rotary compressors, high pressure is constantly applied to the bottom of the vane so that as the rotor rotates, the vane rotates and slides with its tip in contact with the inner wall of the cylinder. A mechanism that applies lubricating oil is used.

11. Generally speaking, the two methods of drying the compressor are the forced lubrication method, which uses a pump installed on the drive shaft of the compressor, and the other, which uses the pressure of the high-pressure fluid compressed by the compressor into a compressed bag. A differential pressure lubrication system that supplies oil by differential pressure is widely used.

However, in the forced lubrication type, as the rotation speed of the compressor increases, the amount of lubrication also increases, which, combined with the centrifugal force acting on the vanes, causes the vanes to be pushed into excessive contact with the cylinder inner wall, resulting in increased wear on the vane tips and the cylinder inner wall. This results in an increase in input power to the compressor, which has the disadvantage of deteriorating the durability and efficiency of the compressor.

On the other hand, in the differential pressure lubrication type, the above-mentioned phenomenon is alleviated by eliminating excessive lubrication, which causes the same drawbacks as in the case of the forced lubrication type, and by providing a mechanism in the lubrication passage to limit the lubrication. .

Figures 1 and 2 show a conventional differential pressure oil supply system.
This figure shows the structure of a vane rotary compressor.

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 cylinder 1, and 3 is slidably inserted into a vane slot 4 provided in rotor 2. The plurality of vanes 5 formed integrally with the rotor 2 are a drive shaft rotatably supported.

Reference numerals 6 and 2 are a front side plate and a rear side plate, respectively, which close both ends of the cylinder 1 to form a working chamber 8 therein, 9 is an inlet port communicating with the working chamber on the low pressure side, and 10 is an inlet connected to the working chamber 8 on the high pressure side. 11 is a discharge valve disposed in the discharge port 10, and 12 is a case, in which a high pressure passage 1 is connected.
3, and a high pressure chamber 14 equipped with a screen 15 that separates and captures lubricating oil in the compressed high pressure fluid, and a low pressure passage 1 whose both ends communicate with the suction pipe connection port 20 and the suction port 9.
9. Reference numeral 16 indicates an oil supply passage that communicates the oil reservoir below the high pressure chamber 14 with the vane bottom space 17, and 18 indicates a passage that limits the oil supply.

The operation of the vane rotary compressor oil supply system constructed as described above will be described below.

When the drive shaft 5 and rotor 2 rotate clockwise in FIG. 2 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 through the discharge port 10 and 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. The lubricating oil separated from the high-pressure fluid is stored below the high-pressure chamber 14, and is supplied to the vane bottom space 17 from the oil supply passage 16 and the passage 18 due to the differential pressure, and is used to suppress the vane 73.

However, when the compressor is started after a certain period of time has passed since the compressor stopped and the pressure of the fluid on the low-pressure side and the pressure of the fluid on the high-pressure side become equal, the differential pressure immediately after the compressor starts will be Because of its small size, the conventional lubricating system described above is known to cause insufficient pressure on the vanes, especially when the rotational speed at the start of the compressor is low, causing the vanes to separate from the inner wall of the cylinder and collide again, a well-known malfunction phenomenon in which the fluid is not compressed. There was a drawback that a phenomenon occurred.

OBJECTS OF THE INVENTION The present invention has been made in view of the drawbacks of the conventional oil supply system described above, and can be used together with the conventional oil supply system to operate the compressor at low speed when there is no pressure difference between the high and low pressures of the compressor. To provide a suction backflow prevention device for a vane rotary compressor, which can prevent vane malfunction and compression failure even when the compressor is started, and does not impair durability or efficiency.

Structure of the Invention In order to achieve this object, the present invention provides a valve body that communicates with and shuts off a suction passage in a suction passage of a vane rotary compressor, and a valve in which the valve body is slidably held through a small gap. a holding body;
A spring is provided in the space formed by the valve body and the valve holding body to urge the valve body to shut off the suction passage.

With this configuration, when the compressor is stopped for a long time and there is no or small pressure difference between the high and low pressures of the compressor, the valve body blocks the suction passage, and immediately after the compressor starts, the valve body blocks the suction passage. In order to continue, the pressure in the working chamber on the suction side decreases due to the increase in volume of the working chamber due to the rotation of the vane.
Therefore, the force acting on the tip of the vane to force the vane into the vane slot 17 is significantly reduced, so that the vane can be reliably brought into contact with the inner wall of the cylinder 17.

In addition, after a certain period of time has passed after startup, the pressure in the space formed by the valve body and the valve holding body decreases, and the valve body gradually attempts to communicate with the suction passage, so the pressure in the working chamber of the suction 11411 The pressure increases gradually, and therefore the force acting on the tip of the vane does not increase dramatically, so the vane is pressed against the inner wall of the cylinder and normal operation can be continued. .

Even if the compressor is started at a low rotation speed when there is no or a small pressure difference between the high and low pressures of the pressure knitting machine, as shown in FIG.

DESCRIPTION OF EXAMPLES An embodiment of the present invention will be described below with reference to the drawings.

Figures 3, 4 & J: Show a vane rotary compressor equipped with a suction check valve according to an embodiment of the present invention.
) 0. Parts that are the same as those of a vane rotary compressor equipped with a conventional differential pressure oil supply system and that have the same effects 1-11 are designated by the same reference numerals 1 to 1, and their explanations will be omitted.

In the figure, 21 is a hole connected to the suction pipe connection port 20.
1. A suction pipe 22 has a passage 21a, a valve seat 22 has a passage 22a which is provided at the pipe connection port 20 and communicates with the passage 21a and the suction passage 19 at both ends thereof, and a valve seat 23 contacts and separates from the valve seat 22 to communicate with the passage 22a. 24 is a valve holding body that slidably holds the valve body 23 through a minute gap 25; 26 is a valve holding body that is integrally fixed to the valve holding body and its outer periphery; A holding fitting 29 has a large number of openings 27 in the valve body 23 and a plurality of claws 28 are retained by being engaged with grooves of the valve seat 22;
This spring is disposed within the space 30 formed by the valve body 4 and the valve body 23 and biases the valve body 23 in a direction to bring the valve body 23 into contact with the valve seat 22.

The operation of the vane rotary compressor equipped with the suction check valve configured as described above-1-4 will be explained below.

If a certain period of time has passed since the compressor stopped and the pressure of the fluid on the low pressure side and the pressure of the fluid on the high pressure side are different, the space 3
Is the pressure inside 0 equal to the pressure inside the suction passage 19?
The valve body 23 is brought into contact with the valve seat 22 by the force of the spring 29.

In this state, compression a'fO: When starting, the fluid in the suction passage 19 is sucked into the working chamber 8 and discharged due to the increase in volume of the working chamber 8 on the first and passenger sides as the bay 73 rotates. .

At this time, at the same time, the vane bottom space 17 is filled with the vane bottom space 1.
Due to the slight pressure difference caused by the increase in the volume of the high pressure chamber 14
Although only a small amount of lubricating oil is supplied through the passage 18 and the oil supply passage 16 (r), the volume of the suction d passage 19 is small, and the pressure within the inter-vehicle space 30 does not change instantly after starting. Therefore, the valve body 23 is a lever that is brought into contact with the valve seat 22. This J'1. As a result, the pressure inside the suction passage 19 drops instantly after starting, and the pressure inside the working chamber 8 also drops correspondingly to the pressure drop, and the tip of the vane 3,
The force acting on the 7Hj4 that causes the vane 3 to be thrown into the 7Hj4 is also reduced. Therefore, the vane 3 is pressed against the inner wall of the cylinder 1 and normal operation can be continued.

Further, the operation is continued to check whether the pressure in the space 3o or the minute gap 2
5, and when the pressure in the 4th passage 22a finally overcomes the j pressure in the space 30 and the 4λJ force of the spring 29, the valve body 23 separates from the valve seat 22 and moves into the passage 22.
The gas in a gradually flows into the suction passage 19, is sucked into the working/auxiliary chamber 8, is compressed and discharged, and the pressure in the high pressure chamber 14 also rises. As a result, the amount of lubricating oil supplied to the vane bottom space 17 also increases, so that the vane 73 is pressed against the inner wall of the cylinder 1 and can continue normal operation.

When further time passes and the valve body 23 moves to the position shown by the two-dot chain line in FIG. 4, its operation is no different from that of the conventional vane rotary compressor.

In this way, even if the compressor is stopped for a long time and the compressor is started to check whether there is a difference in high or low pressure,
Since the valve body 23 contacts the valve seat 22 and tries to continue blocking the suction passage 19, the pressure in the working chamber 8 on the suction side decreases due to the increase in the volume of the working chamber 8 as the vane 3 rotates. ,
Therefore, the force acting on the tip of the vane 3 to force the vane 3 into the vane throttle I□4 also becomes significantly smaller. As a result, the vane 3 can be reliably pressed against the inner wall of the cylinder 1, and even after a certain period of time has passed after the compressor is started, the pressure in the space formed by the valve body 23 and the holder 24 will drop. Then, the valve body 23 is connected to the valve seat 22.
Try to withdraw more gradually. Therefore, the pressure in the working chamber 8 on the suction side gradually increases, and therefore the force acting on the tip of the vane 73 does not increase suddenly, so the vane 3id is pressed against the inner wall of the cylinder 1 and operates normally. Even if the compressor is started at a low rotation speed when there is no or small pressure difference between the high and low pressures of the compressor, it is possible to prevent the vane from malfunctioning.

In this embodiment, when the valve body 23 is in contact with the valve seat 22, it blocks the suction passage 19 and the passage 22a, but only the suction passage 19 and the passage 22a i have a small cross-sectional area that communicates with the passage 21a. It is clear that even if a bypass passage is provided, the same effects as in the above embodiment can be obtained.

Furthermore, in the previous embodiment, a minute gap was provided between the valve body 23 and the valve holding body 24, but a minute gap was provided between the valve body 23-1: or the valve holding body 24 to communicate the suction passage 19 and the space 30. It is clear that even if a through hole having a cross-sectional area is provided, the same effect as in the above embodiment can be obtained.

Effects of the Invention As is clear from the above description, the present invention provides a valve body for communicating and blocking a suction passage in a suction passage of a vane rotary compressor;
A valve holder is provided in which the valve element is slidably held through a small gap, and a spring is provided in a space formed by the valve element and the valve holder to urge the valve element to block the suction passage. If the compressor has stopped for a long time and there is no or small pressure difference between the high and low pressures of the compressor, even if the compressor is started, the force acting on the tip of the vane to force the vane into the vane slot is The vane is extremely small and the vane can be reliably pressed against the inner wall of the cylinder. - After a certain period of time has passed after startup, the pressure in the space formed by the valve body and the valve holder decreases, and the valve body gradually attempts to communicate with the suction passage, but the suction side operation The pressure in the chamber gradually rises, and the force acting on the tip of the vane does not suddenly increase, so that the vane can be pressed against the inner wall of the cylinder and normal operation can be continued. In this way, even if the compressor is started at a low rotation speed when there is no or a small pressure difference between the high and low pressures of the compressor, it is possible to prevent vane malfunction or poor compression.

4. The first part of the drawing! Figure 1 is a longitudinal sectional view of a conventional vane rotary compressor, Figure 2 is a plan view of the same compressor with the front side plate removed, and Figure 3 is a diagram of an embodiment of the present invention. FIG. 4 is a vertical cross-sectional view of a rotary vane compressor equipped with suction backflow prevention + Aii'i, and FIG. 4 is an enlarged cross-sectional view of the main part taken along the line Y--Y in FIG. 3.

1- cylinder, 2... rotor, 3-... vane, 4 vane slot, 6... drive shaft, 6...
Front side plate, 7 ・Rear side plate, 8 ... Working chamber, 19
... Suction passage, 23 ... Valve body, 24 ... Valve holder, 25 ... Minute gap, 29 - ... Spring.

Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure B 16 Figure 2 Σ! H 6J ＼

Claims (1)

[Claims] A cylinder having a U-shaped inner wall, a rotor disposed inside the cylinder and having a part of its outer periphery forming a minute gap with the cylinder inner wall, and the rotor being slidably inserted into a vane slot provided therein. Ta4! a number of vanes, 1 drive shaft formed integrally with the rotor and rotatably supported; a front side plate and a rear side plate that close both ends of the cylinder to form a working chamber therein; Supplementary Note: A vane rotary compression mechanism is constructed, which consists of a suction straight path and a discharge passage connected to the working chamber across the portion where the rotor outer periphery and the cylinder inner wall are close, and a suction passage is provided in the suction 1 path. 1Il
s vm g Vfr, a valve holder that slidably holds the valve element through a small gap, and the valve element blocks the suction passage in the space formed by the valve element and the valve holder. A spring that biases the
Machine suction backflow prevention device.