JPH03249385A - Variable displacement gas compressor - Google Patents

Abstract

PURPOSE:To simplify a variable displacement gas compressor in structure by forming two damper chambers, filled up each with an incompressible viscous fluid, in the inner part of an unloader piston, while keeping the total volume added with each volume constant, and forming a minute clearance interconnecting these two damper chambers with each other. CONSTITUTION:An unloader piston 10 receives an alternate load and vibrates up and down by pressure fluctuations in a gas compressor 12. When the piston 10 moves upward or downward, volume in a damper chamber 56a increases or decreases and simultaneously volume in a damper chamber 56b increases or decreases as well, therefore oil passes through a minute clearance between an outer circumferential surface of a seal ring 54 and an inner circumferential surface of a small diametral hole 30a and enters the damper chamber where volume is increased. In this case, as both inner and outer diameters of these chambers 56a, 56b are all the same, even if the piston 10 reciprocates, the total volume added with each volume of these chambers 56a, 56b is kept constant, therefore it is unnecessary to do any supply of oil for these chambers 56a, 56b and to let oil in these chambers escape to the other places.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a variable displacement gas compressor.

(Prior Art) The present applicant has already applied for a variable displacement gas compressor shown in FIGS. 2 and 3 in Japanese Patent Application No. 1-86639.

In Figures 2 and 3, 1 is a cylinder, 2 is a piston, 3 is a valve plate, 4 is a throat to the cylinder, 5 is a suction cavity, 6 is a suction valve, 7 is a discharge valve, 8 is a discharge chamber, and 9 is a suction cavity. Unloader cylinder, 10, unloader piston, 25
2 is a piston ring wound around the piston 2, and 26 is a washer fixed to the lower end of the unloader cylinder 9.

The lower end of the unloader cylinder 9 is fixed to the valve plate 3, and the upper end is covered by a cover 20.

Inside this unloader cylinder 9 is an unloader piston 1.
0 is sealed and slidably fitted, and a chamber 19 bounded below the unloader piston 10 communicates with the gas compression chamber 12 through an opening 18.

A two-stage hole 30 consisting of a large-diameter hole 30a and a small-diameter hole 30b extending downward from the top surface of the unloader piston 10 is bored along the axis of the unloader piston 10. The upper end of the rod 31 is fastened to the center of the cover 20 by a bolt 32.

A seal ring 34 is fitted on the outer peripheral surface of a flange 33 formed at the lower part of this rod 31.
A minute gap is formed between the outer circumferential surface of No. 4 and the inner circumferential surface of the small diameter hole 30b. Further, a ring 35 that is vertically movably fitted into the middle of the rod 31 is connected to the unloader piston 10 by a snap ring 36 that is fitted into the large diameter hole 30a.
Fixed. The inner peripheral surface of this ring 35 and the rod 3
A minute gap 35a is formed between the outer circumferential surface of the ring 35 and the inner circumferential surface of the large diameter hole 30a. has been done.

Thus, the damper chamber 39 is located below the seal ring 34.
A damper chamber 40 is defined between the seal ring 34 and the ring 35, and an operating chamber 41 is defined above the ring 35.
These damper chambers 39 and 40 are filled with incompressible viscous fluid, such as oil.

The working chamber 41 communicates with the discharge chamber 8 through a throttle hole 42 formed in the cover 20, and also includes a gas passage 43 formed in the cover 20, a gas pipe 44, and a gas passage 45 formed in the valve plate 3. , a gas pipe 46, and a control valve 47 to communicate with a low pressure source such as a gas suction pipe.

On the other hand, an oil supply hole 48 is drilled through Lot 31 along its axis, and the upper end of this oil supply hole 48 is connected to an oil supply pipe 49a, which is connected to an oil supply hole 49a drilled in the valve plate 3. It communicates with the oil tank 50 via the hole 49b and the oil pipe 49c. Further, the lower end of the oil supply hole 48 is opened and closed by a check valve 51 disposed on the lower end surface of the lower flange 33. This check valve 51 is connected to a holding guide 53 fixed to the lower end surface of the lower flange 33.
The lower flange 3
It is pressed against the lower end surface of 3.

When the piston 2 moves back, gas passes through the suction passage 11 formed in the valve plate 3 from the suction cavity 5, pushes open the suction valve 6, and is sucked into the gas compression chamber 12.

When the piston 2 moves forward, the gas in the gas compression chamber 12 is compressed, pushes the discharge valve 7 open, enters the discharge chamber 8 through the passage 13, and is discharged from there through a discharge pipe (not shown).

When the compressor is in operation, the high pressure gas in the discharge chamber 8 flows into the working chamber 41 through the throttle hole 42, and at the same time, the high pressure gas compressed in the gas compression chamber 12 passes through the opening 1B and the chamber 19 into the unloader. It flows through a small gap between the inner peripheral surface of the cylinder 9 and the outer peripheral surface of the unloader piston 10. Then, the gas in this working chamber 41 is converted into gas ii! i road 4
3. The gas is released to a low pressure source through a gas pipe 44, a gas passage 45, a bypass pipe 46, and a control valve 47, and the control valve 47 controls the flow rate of the gas passing therethrough.

In this way, by increasing or decreasing the pressure in the working chamber 41 with respect to the average pressure of the gas acting in the chamber 19, the unloader piston 10 is moved up and down and its vertical position can be arbitrarily changed. Then, the top clearance volume consisting of the chamber 19 and the opening 18 changes, and the capacity of the compressor changes steplessly.

On the other hand, since the pressure in the chamber 19 fluctuates as the pressure in the gas compression chamber 12 fluctuates, the unloader piston IO receives an alternating load and vibrates up and down.
Vibration of the unloader piston 10 is suppressed by the oil flowing in and out.

That is, when the unloader piston 10 moves upward, the oil pressure inside the chamber 39 decreases, and the oil pressure inside the chamber 39 increases, and this oil flows into a small amount between the outer circumferential surface of the seal ring 34 and the inner circumferential surface of the small diameter hole 30b. The oil enters the damper chamber 40 through the gap, and further flows into the working chamber 41 through the minute gap between the outer circumferential surface of the loft 31 and the inner circumferential surface of the ring 35, and when the oil passes through these minute gaps, The upward movement of the unloader piston 10 is suppressed by the flow resistance.

Conversely, when the unloader piston 10 moves downward, the oil pressure in the damper chamber 40 increases as the internal volume decreases, and this oil flows between the outer circumferential surface of the seal ring 34 and the inner circumferential surface of the small diameter hole 30b. At the same time as it enters the damper chamber 39 through the minute gap, it is about to be pushed out into the working chamber 41 through the minute gap between the outer circumferential surface of the rod 31 and the inner circumferential surface of the ring 35.

However, if the flow resistance due to the former minute gap is greater than that due to the latter minute gap, the oil in the damper chamber 40 is pushed out only to the working chamber 41 and does not enter the damper chamber 39. Then, as the unloader piston 10 moves downward, the pressure in the damper chamber 39 decreases, and the pressure difference between the pressure in the damper chamber 39 and the pressure in the oil supply hole 48 becomes greater than the pressing force by the presser spring 52. When it becomes large, the check valve 51
opens. Then, the oil in the oil tank 50 enters the holding guide 53 through the oil pipe 49c, oil hole 49b, oil supply pipe 49a, oil supply hole 48, and check valve 51, and enters the oil outflow hole 53a formed therein. It flows into the damper chamber 39 through the damper chamber 39 to stop a vacuum region from being generated in the damper chamber 39.

(Problem B to be solved by the invention) In the above conventional compressor, the unloader piston 10
When the damper chamber 39 moves up and down under an alternating load, a difference occurs between the volume change amount of the damper chamber 39 and the volume change amount of the damper chamber 40. That is, the volume of the damper chamber 39 and the damper must be replenished with oil, and for this purpose, the oil supply hole 48, the oil supply pipe 49a, the oil hole 49c, the oil pipe 49c, the oil tank 50, the check valve 51, Holding spring 52, holding guide 5
An oil supply mechanism consisting of three components is required, and as a result,
There was a problem that not only the structure became complicated but also the cost increased.

(Means for Solving the Problems) The present invention has been proposed to solve the above problems, and its gist is to seal an unloader piston in an unloader cylinder communicating with a gas compression chamber. In a variable capacity gas compressor that is movably fitted and controls the capacity by changing the output volume by moving the unloader piston, each of the unloader pistons is filled with an incompressible viscous fluid. The volume of each of the damper chambers changes as the unloader piston moves, but the total volume of the sum of the volumes remains constant.A micro gap is formed that interconnects the plurality of damper chambers. A variable capacity gas compressor is characterized in that it has the following features:

(Function) Since the present invention has the above configuration, as the unloader piston reciprocates, the viscous fluids filled in the plurality of damper chambers are exchanged with each other through the minute gaps, resulting in resistance to flow when passing through the minute gaps. This suppresses the reciprocating movement of the unloader piston.

(Example) One embodiment of the invention is shown in FIG.

An annular flange 55 is formed in the middle of the rod 31,
Seal ring 5 fitted on the outer peripheral surface of this flange 55
A minute gap is formed between the outer peripheral surface of the hole 4 and the inner peripheral surface of the large diameter hole 30a.

On the other hand, a gasket 6 is provided on the upper end surface of the unloader piston 10.
A sleeve 63 is placed through the sleeve 63.
is fastened to the unloader piston 10 by a bolt 64. Seal rings 62a and 62b for sealing the gap between the sleeve 63 and the outer circumferential surface of the rod 31 are embedded in the inner circumferential surface of the sleeve 63, and the upper seal ring 6
2a seals the gas above it, and the lower seal ring 62b seals the oil below it. .

Seal rings 60a and 60b are embedded in the lower outer circumferential surface of the rod 31 to seal the gap with the inner circumferential surface of the small diameter hole 30b, and the upper seal ring 60a seals oil above it, and the lower seal ring 60b soles the gas below it.

Thus, an annular damper chamber 56a is formed above the flange 55, which is defined by the upper surface of the flange 55, the lower surface of the sleeve 63, the outer peripheral surface of the rod 31, and the inner peripheral surface of the large diameter hole 30a. Below the flange 55, the shoulder 30c of the double hole 30 and the rod 31.
An annular damper chamber 56b is defined by the outer peripheral surface of the large diameter hole 30a and the inner peripheral surface of the large diameter hole 30a. These damper chambers 56a and 56b are filled with an incompressible viscous fluid, such as oil, and as the unloader piston 10 moves up and down, the oil contacts the outer peripheral surface of the seal ring 54 and the inner peripheral surface of the large diameter hole 30a. They are designed to communicate with each other through a minute gap formed between them.

A gas chamber 66 is defined above the unloader piston 10 by the upper surface of the sleeve 63, the lower surface of the cover 20, the inner peripheral surface of the unloader cylinder 9, and the outer peripheral surface of the rod 31.
This gas chamber 66 is connected to a high pressure source 7 through a through hole 69 formed in the unloader cylinder 9, a gas pipe 46, and a pressure control valve 47.
1. For example, the gas chamber 66 communicates with a discharge chamber where discharged gas is stored, and this gas chamber 66 is connected to a gas chamber bounded by the lower end surface of the rod 31 and the small diameter hole 30b through a through hole 67 bored in the loft 31. 61 is always in contact.

A coil spring 68 is interposed in a compressed state between the inner lower surface of the unloader cylinder 9 and a shoulder 70 formed on the middle outer circumference of the unloader piston 10, and the coil spring 68 pushes the unloader piston 10 upward. It is being

The rest of the structure is similar to the conventional one shown in FIGS. 2 and 3, and corresponding members are given the same reference numerals.

Therefore, when controlling the capacity of the compressor, the high pressure source 71
The high-pressure gas is reduced to an appropriate control pressure by the pressure control valve 47, and this control pressure is introduced into the gas chamber 66 through the gas pipe 46 and the through hole 69. The downward force generated by the control pressure introduced into the gas chamber 66 and the upward force generated by the average pressure in the gas compression chamber 12 introduced into the chamber 19 and the elastic force of the coil spring 68. The unloader piston 10 is moved up and down within the unloader cylinder 9 according to the difference, and the top clearance volume is changed, thereby steplessly controlling the capacity of the compressor. In addition,
As the unloader piston 10 moves up and down, gas in the chamber 61 moves in and out through the gas passage 67, and the pressure in the chamber 61 is maintained at the same pressure as the pressure in the chamber 66.

Due to pressure fluctuations within the gas compression chamber 12, the unloader piston 10 receives an alternating load and vibrates up and down.

When the unloader piston 10 moves upward, i.e.
During forward movement, the volume of the damper chamber 56b decreases and at the same time the volume of the damper chamber 56a increases. Then, the damper chamber 56
The oil pressure in a increases, and this oil enters the damper chamber 56a through a minute gap between the outer peripheral surface of the sole ring 54 and the inner peripheral surface of the small diameter hole 30a, and due to the flow resistance at this time, the unloader piston 10 vibration is suppressed.

When the unloader piston 10 moves downward, i.e.
During the return movement, the volume of the damper chamber 56a decreases and at the same time the volume of the damper chamber 56b increases. Then, the damper chamber 56
The oil pressure in a increases, and this oil enters the damper chamber 56b through a minute gap between the outer peripheral surface of the sole ring 54 and the inner peripheral surface of the small diameter hole 30a, and due to the flow resistance at this time, the unloader piston 10 vibration is suppressed.

Since the inner and outer diameters of the damper chambers 56a and 56b are the same, even if the unloader piston 10 reciprocates, the increase or decrease in the volume of the damper chamber 56a and the volume of the damper chamber 56b are the same. The total volume of the volume of the chamber 56a and the volume of the damper chamber 56b is always constant regardless of the movement of the unloader piston 10. Therefore, even if the unloader piston lO reciprocates, the volume of the damper chambers 56a and 56b remains constant.
The oil in the damper chamber 56 is simply replaced.
Replenishment of oil to damper chambers 56a, 56b and damper chambers 56a, 56b.
There is no need to release the oil in the passage 6b to another place.
7 acts to increase the effective pressure receiving area of the unloader piston 10, so the unloader piston 10 can be made smaller.

(Effect of the invention) In the present invention, even if the unloader piston moves, the total volume of the volumes of the plurality of damper chambers is always constant and does not change. Replaced.

Therefore, there is no need to replenish viscous fluid to these damper chambers or to discharge the viscous fluid inside these damper chambers, so unlike conventional systems, a mechanism for replenishing viscous fluid into the damper chambers can be omitted. As a result, the structure can be simplified and costs can be significantly reduced.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional view showing one embodiment of the present invention. Second
31 and 31 show an example of a conventional variable capacity gas compressor, FIG. 2 is a longitudinal sectional view, and FIG. 3 is a partially enlarged view of FIG. 2. Gas compression chamber-42, unloader cylinder 9, unloader 1
Figure 2

Claims (1)

[Claims] In a variable capacity gas compressor, an unloader piston is fitted in an unloader cylinder that communicates with a gas compression chamber in a sealed and slidable manner, and the top clearance volume is changed by moving the unloader piston to control the capacity. Each of the unloader pistons is filled with an incompressible viscous fluid, and each volume changes as the unloader piston moves, but the total volume of each damper chamber remains constant. 1. A variable displacement gas compressor characterized in that a small gap is formed between the damper chambers and the plurality of damper chambers to communicate with each other.