JPH02218881A - Scroll type compressor - Google Patents

Abstract

PURPOSE:To reduce the load applied to a swing scroll at the time of restarting the compressing operation by disposing a release valve for reducing a differential pressure between the inlet port side and the back pressure chamber side on at least one of the both sides. CONSTITUTION:When a driving shaft 6 is rotated to rotate a swing scroll 8, the air is sucked from an inlet port 2A through an intake opening 4, compressed in a compression chamber 10 formed between a fixed scroll 3 and the swing scroll 8, and then discharged from a discharge opening 5. In this case, an exhaust port 21 communicated with a back pressure chamber 11 is formed on the major diameter cylinder part 1B of a casing. Also, an electromagnetic release valve 22 for releasing the compressed air in the back pressure chamber 11 to the outside is disposed on the exhaust port 21. The release valve 22 is opened only for a determined time at the time of restarting the compressing operation. Hence, the pressure in the back pressure chamber 11 is reduced to reduce the differential pressure with the compression chamber 10 side, whereby the load applied to the swing scroll 8 is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a scroll compressor suitable for use in compressing a gas such as air or a refrigerant (hereinafter referred to as air).

[Conventional technology]

In FIG. 7 and FIG. 8, which shows a conventional scroll compressor, l is a casing, and the casing l includes a small-diameter cylindrical bearing part IA, a large-diameter cylindrical part IB, and a large-diameter cylindrical bearing part IB. The inside of part IB is composed of a joint receiving part IC that projects radially inward, and an intake passage 2 is formed on the outside of the casing 1, with an intake boat 2A on the upper side and a communication boat 2B on the lower side. There is. In addition, if necessary, the intake boat 2
A suction throttle valve or check valve (not shown) that opens only during suction is provided on the A side.

Reference numeral 3 denotes a fixed scroll fixed to the end surface of the large-diameter cylindrical portion IB of the casing 1, and the fixed scroll 3 includes an end plate 3A;
An involute or a spiral-shaped wrap portion 3B close to the involute is provided upright on the end plate 3A, and the wrap portion 3B
It is composed of a cylindrical portion 3C erected on the outer circumferential side of the cylindrical portion 3C. A suction port 4 having a suction boat 4A connected to the communication boat 2B of the intake passage 2 is formed in the cylindrical portion 3C, and a discharge port 5 is bored in the center of the end plate 3A.

Reference numeral 6 denotes a drive shaft located on the same axis 0101 as the fixed scroll 3 and provided in the casing 1. The drive shaft 6 is rotatably supported by a bearing portion IA via a bearing 7.

The upper end side of the drive shaft 6 in the figure becomes the boob attachment part 6A, and the lower end side has the axis 02-0□ of the fixed scroll 3. The axis 01-8 of the fixed scroll 3 is an orbiting scroll, and the orbiting scroll 8 is an end plate 8A. An involute or a spiral-shaped wrap portion 8B close to an involute, which is provided upright on the front surface 8Al of the end plate 8A and rotates while overlapping the wrap portion 3B of the fixed scroll 3, and a rear surface 8A of the end plate 8A protrudes from the center. The orbiting scroll 8 is rotatably supported by the crankshaft 6B via an orbiting bearing 9 fitted to the boss section 8C. And mirror plate 8
A plurality of compression chambers io, io are formed between the wrap portion 8B on the front side of A and the wrap portion 3B of the fixed scroll 3,
Inside each compression chamber 10, the suction port 4 side becomes a low pressure section 10A, the discharge port 5 side becomes a high pressure section 10B, and the middle thereof becomes an intermediate pressure section 10G.

In addition, the orbiting scroll 8 and the large diameter portion IB of the casing 1
A back pressure chamber 11 is defined on the rear surface 8A of the end plate 8A, and a back pressure introduction hole 12 is bored in the end plate 8A to communicate the back pressure chamber 11 with the intermediate pressure section 10C of the compression chamber 10. It is set up.

Furthermore, in the figure, 13 is an Oldham joint provided between the end plate 8A and the joint receiving part IC of the casing 1 to prevent rotation of the orbiting scroll 8, and 14 is an Oldham joint located in the back pressure chamber 11 and connected to the drive shaft 6. The installed counterweight is shown.

The conventional technology is configured as described above, and when compressing air, the drive shaft 6 is rotated to revolve the orbiting scroll 8, and the air is sucked from the intake boat 2A through the intake path 2 and the intake port 4. A compression chamber 10 formed between the fixed scroll 3 and the orbiting scroll 8 is sealed, and air is compressed by gradually contracting the compression chamber 10 while the orbiting scroll 8 revolves, and air pressure is released from the discharge port 5. Compressed air is discharged to the equipment side.

During the compression operation described above, due to the pressure of the air that is sealed in the compression chamber 1O and gradually compressed, a separating force in the thrust direction that separates the orbiting scroll 8 from the fixed scroll 3 acts on the orbiting scroll 8. A phenomenon occurs in which . Therefore, the pressure in the intermediate pressure section 10G of the compression chamber 1O is introduced into the back pressure chamber 11 through the back pressure introduction hole 12, and is applied to the back side of the orbiting scroll 8 to balance the pressure. It is designed to prevent it from rising.

[Problems to be Solved by the Invention] By the way, during compression operation, the suction port 4 side of the compression chamber lO is in a state close to atmospheric pressure, whereas the vicinity of the discharge port 5 is in a high pressure state of, for example, 8 kgf/cod". Become.

However, after the compression operation is stopped, the compressed air in the tank leaks from the discharge port 5 through the gap between the lap parts 3B and 8B, and the intermediate pressure part 10C of the compression chamber 10 increases the pressure in the back pressure chamber 11. A phenomenon occurs in which the pressure becomes the same as the tank pressure.

However, at the time of restart, as shown in FIG. 8, the pressure on the suction port 4 side decreases due to the suction action, and the pressure on the back pressure chamber 11 side increases, so that the differential pressure ΔP increases. For this reason, the orbiting scroll 8
An excessive pressing force is applied to the fixed scroll 3 side, and the tooth tips of the lap portion 8B may cause a galling phenomenon with the end plate 3A of the fixed scroll 3, and there is a possibility that the orbiting scroll 8 may become unable to rotate.

The present invention has been made in view of the above-mentioned drawbacks of the prior art, and it is an object of the present invention to provide a scroll compressor that maintains the pressure balance between the compression chamber and the back pressure chamber and can be started smoothly.

[Means to solve the problem]

The feature of the means of the present invention configured to solve the above-mentioned problems is that the differential pressure between the suction port side and the back pressure chamber side is applied to at least one of the suction port side and the back pressure chamber side. The reason is that an on-off valve is provided to reduce the amount of water.

[Effect]

With this configuration, when the differential pressure between the suction port side and the back pressure chamber side becomes large (when it becomes large, the on-off valve is operated to release the compressed air on the back pressure chamber side to the atmosphere, or By introducing it to the suction port side, the differential pressure is reduced.

[Example 1] Hereinafter, an example of the present invention will be described in detail based on FIGS. 1 to 6. Note that the same reference numerals are given to the same components as those of the prior art described above, and the explanation thereof will be omitted. Furthermore, since the basic operation of compressing air by rotating the orbiting scroll 8 in each embodiment is substantially the same as that of the prior art, a description of the operation will be omitted.

First, FIG. 1 shows a first embodiment of the present invention, and the feature of this embodiment is that an exhaust port 21 is provided in the large diameter cylindrical portion IB of the casing 1 and communicates with the back pressure chamber 11. The opening 21 is provided with an electromagnetic release valve 22 for releasing the compressed air in the back pressure chamber 11 to the outside. Note that the release valve 22 is opened only for a predetermined period of time after starting, for example, by a starting switch, a timer, or the like.

According to this embodiment, when the compression operation is restarted, the release valve 22 is opened for a predetermined period of time, and the compressed air in the back pressure chamber 11 is discharged to the outside to lower the pressure, thereby increasing the differential pressure with the compression chamber 10 side. can be reduced, and the load on the orbiting scroll 8 at the time of restart can be reduced.

FIG. 2 shows a second embodiment of the present invention, and the feature of this embodiment is that a back pressure chamber 1 is provided in the large diameter cylindrical portion IB of the casing 1.
1, an air supply port 32 that communicates with the intake path 2, and an electromagnetic release valve 34 in the middle of a pipe 33 connecting the exhaust port 31 and the air supply port 32. It is in.

According to this embodiment, the release valve 34 is opened for a predetermined period of time when the compression operation is restarted, and the compressed air in the back pressure chamber 11 is sequentially passed through the exhaust port 31, the piping 33, and the air supply port 32 to the intake path 34. supply within. As a result, the pressure inside the back pressure chamber 11 can be lowered, and by sending compressed air from the intake path 2 to the suction port 4 side, a drop in pressure due to the suction action can be prevented.
It can reduce the differential pressure on both sides.

Note that instead of the electromagnetic release valves 22 and 34 in the first and second embodiments described above, a check valve 41 having a valve body 42 and a spring 43 as shown in FIG. 3 may be used (in this case, The boat 44 on one side is connected to the exhaust port 21 on the back pressure chamber 11 side.
．． 31, and the boat 44 on the other side is opened to the atmosphere in the case of the first embodiment, and connected to the air supply port 32 side in the case of the second embodiment.

In this case, a predetermined residual pressure can be maintained in the back pressure chamber 11 by the load of the spring 43 of the check valve 41.

Next, FIG. 4 shows a third embodiment of the present invention.

The feature of this embodiment is that an air supply port 51 that opens to the intake path 2 is provided in the large diameter cylindrical portion IB of the casing 1, and an air tank 53 is connected to the air supply port 51 via a pipe 52. An electromagnetic release valve 54 is provided in the middle of the piping 52, and an electromagnetic cutoff valve 55 is provided in the intake/air boat 2A of the intake path 2.

According to this embodiment, when restarting the compression operation, the cutoff valve 55 is kept closed for a predetermined period of time, the release valve 54 is opened, and the compressed air in the air tank 53 is passed through the piping 52 to the intake passage 52. By supplying air into the suction port 4 from above, a pressure drop on the suction chamber 4 side is prevented and smooth startup of the orbiting scroll 8 is ensured.

Furthermore, FIGS. 5 and 6 show a fourth embodiment of the present invention,
The feature of this embodiment is that a ventilation hole 61 on one side that opens to the suction port 4 is bored in the fixed scroll 3, and a ventilation hole 61 on the other side that opens to the back pressure chamber 11 is provided in the large diameter cylindrical portion IB of the casing 1. This is because a port 62 is bored and a differential pressure regulating valve 64 is provided in the middle of a pipe 63 that communicates the minus side vent 61 and the other side vent 62.

Here, the differential pressure regulating valve 64 is shown in FIG. In the figure, 65 is a valve casing, and the inside of the valve casing 65 is a pilot valve chamber 66 between two partition walls 65A and 65B.
, an intermediate chamber 67 and a stop valve chamber 68. 69 is a cylinder located in the pilot valve chamber 66 and formed in the valve casing 65, and inside the cylinder 69 is an action chamber 6 of a valve head 80A of a pilot valve body 80, which will be described later.
9A, and there is a valve seat 7 on the periphery of the cylinder 69.
0 is formed protrudingly in an annular shape. 71 is the valve casing 6
m connection boats provided on the negative side connection boat 7.
1 communicates with the working chamber 69A via an orifice 72. In the figure, 73 is a vent hole for opening the inside of the pilot valve chamber 66 to the atmosphere.

On the other hand, reference numeral 74 indicates the other side connection boat that opens into the stop valve chamber 68 and is formed in the valve casing 65, and 75 indicates an intermediate connection boat that opens into the intermediate chamber 67 and is formed in the valve casing 65. 68 and the intermediate chamber 67 communicate with each other through an orifice 76 bored in the partition wall 65B. Further, 77 indicates a rod sliding hole formed in one partition wall 65A of the valve casing 65, and 78 indicates a ventilation hole formed in the other partition wall 65B. A valve seat 79 is formed along the edge of the ventilation hole 78.

Next, 80 is a pilot valve body, and the pilot valve body 80
has a collar 80A on the outer periphery, and the lower end in the axial direction is the valve head 80A.
It consists of a large diameter valve body 80A having a shape of , and a small diameter rod portion 80B which is formed protruding from the upper end side of the valve body 80A and whose tip end surface is a contact surface 80B1. The pilot valve body 80 is slidably provided in the valve casing 65 with the valve head 80A3 inserted into the cylinder 69 and the rod portion 80B inserted into the rod sliding hole 77. 8
Reference numeral 1 denotes a spring tensioned between the one side partition wall 65A of the valve casing 65 and the flange 80A of the pilot valve body 80.
A is always biased in the direction of seating on the valve seat 70.

Reference numeral 82 denotes a ball valve body disposed within the stop valve chamber 68, and the ball valve body 82 is normally seated on the valve seat 79 by a spring 83.

The differential pressure regulating valve 64 of this embodiment is constructed as described above, with the - side connection boat 71 being connected to the one side ventilation hole 61 via the piping 63A, and the other side connection boat 74 being connected to the piping 63B.
is connected to the other side vent 62 via the intermediate connection boat 7.
5 is connected to one side ventilation hole 61 via piping 63G. Therefore, next, the adjustment of the pressure balance when the differential pressure adjustment valve 64 is used will be explained.

After the compression operation is stopped, the suction throttle valve installed on the suction boat 2A of the intake passage 2 closes, and both the suction chamber 4 and the back pressure chamber 11 are at the same high pressure close to the tank pressure. The pilot valve body 80 is pushed toward the stop valve chamber 68 against the spring force of the spring 81 due to the pressure receiving area difference between the valve head 80A2 and the contact surface 80B of the rod portion 80B, and The surface 80B pushes the ball valve body 82 up and away from the valve seat 79, and the stop valve chamber 68 and the intermediate chamber 67 are in communication with each other.

When the compression operation is resumed in this state, the suction action of the compression chamber 10 causes the piping 63B to flow from the back pressure chamber 11.

Differential pressure regulating valve 64. Suction port 4 flll via piping 63C
An air flow is generated in the back pressure chamber 11, and no pressure rise occurs in the back pressure chamber 11. On the other hand, as time passes after the restart, the pressure inside the suction port 4 decreases due to the suction action, so the pilot valve body 80 is moved in the direction in which the flange 80 A + is seated on the valve seat 70 by the spring force of the spring 81. Although it is energized, the action chamber 69A
Since the m connecting boats 71 are in communication with each other through the orifice 72, the pilot valve body 80 is gradually seated.

When the pilot valve element 80 is completely seated, the ball valve element 82 is also seated, the ventilation hole 78 is blocked, and normal operation begins in this state. Since the pressure is lower than that on the back pressure chamber ll side,
The pilot valve body 80 remains seated on the valve seat 70.

According to this embodiment, the pilot valve body 80 is operated using differential pressure, and when the back pressure chamber 11 side becomes high pressure, the ball valve body 82 is opened and compressed air is introduced into the suction port 4 side. As a result, the valve mechanism has excellent durability, and it is possible to prevent the compressed air containing oil in the back pressure chamber 11 from contaminating the outside air.

[Effects of the Invention] As described above, the present invention is constructed so that the differential pressure can be reduced by providing an on-off valve on at least one of the suction chamber side and the back pressure chamber side. It is possible to prevent an excessive pressing force from acting on the orbiting scroll at the time of startup, so that the scroll compressor can be started smoothly, and abnormal wear of the lap portion and end plate can be prevented.

[Brief explanation of the drawing]

1 to 6 show embodiments of the present invention, FIG. 1 is a longitudinal sectional view showing the overall configuration of a scroll compressor according to the first embodiment, and FIG. FIG. 3 is a longitudinal cross-sectional view of a check valve that can be used in the first and second embodiments, and FIG. 4 is a cross-sectional view of a check valve that can be used in the third embodiment. FIG. 5 is a cross-sectional view of main parts showing the overall structure of a scroll compressor according to the fourth embodiment. FIG. 6 is a cross-sectional view of main parts showing the overall structure of a scroll compressor according to the fourth embodiment. FIG. An enlarged vertical cross-sectional view of the regulating valve, Figures 7 and 8 show the prior art, Figure 7 is a vertical cross-sectional view of the scroll compressor, and Figure 8 is the suction part side and back pressure chamber side at the time of restart. FIG. 3 is a diagram showing changes in pressure. 1...Casing, 3...Fixed scroll, 4...
・Suction port, 6... Drive shaft, 8... Orbiting scroll,
10... Compression chamber, 11... Back pressure chamber, 22, 34.4
1...Opening valve, 54...Shutoff valve, 64...Differential pressure regulating valve.

Claims (1)

[Claims] a casing, a fixed scroll fixed to the casing, having a spiral wrap portion formed on the end plate, having a suction port located on the outer peripheral side of the end plate, and having a discharge port located on the center side of the end plate; a drive shaft rotatably provided on the casing; and a spiral-shaped drive shaft rotatably provided on the drive shaft, the end plate overlapping the wrap portion of the fixed scroll to form a compression chamber while rotating. In a scroll compressor comprising an orbiting scroll in which a wrap portion is erected, and a back pressure chamber located on the back side of the end plate of the orbiting scroll and defined in the casing, the suction port side and the back pressure chamber A scroll compressor characterized in that an on-off valve is provided on at least one of the sides to reduce the differential pressure between the suction port side and the back pressure chamber side.