JPH09170552A - Mutually facing piston type compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a small-sized gas compressor having a low cost, stabilized performance and small amounts of noise and mechanical vibration, by arranging two pieces of projecting type movable piston given reciprocating motions synchronously by a reciprocating means on the concentric shafts to be opposite to each other on the concentric shafts and composing the reciprocating means of a linear motor. SOLUTION: The main body 12 of a compressor 1 encloses a suction part plug 14, a medium pressure suction valve 16, and a high pressure part plug 20 and a high pressure ejection valve 19 in diametral direction symmetrically with respect to the part in which a fixed cylinder 4 is composed. Two pieces of projecting type movable piston 2 are formed to be movable piston parts fitted in a fixed cylinder 4 at their top end parts and the outer peripheral parts of the bottom end parts are constituted as amateur parts of a linear motor. And the outer diametral parts of 2 pieces of protecting type fixed piston 3 are fittingly inserted in the inner diametral part of the movable piston which is the large diametral bottom end part of the projecting type movable piston 2 and thereby a medium pressure compressed space part 6, a fixed cylinder side back space 24 and a fixed piston side back space 25 are partitioned from each other in this way.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compressor for compressing a gas fluid, and more particularly to a microminiature Joule-Thomson expansion type refrigerator or an opposed piston type compressor used for portable painting or the like. .

[0002]

2. Description of the Related Art Conventionally, crankshaft driven piston type gas compressors and linear motor driven one stage compression type gas compressors are commercially available. A multistage compressor for obtaining a higher gas pressure by connecting a plurality of piston type gas compressors and the like is also known. However, all of them have relatively large capacities, and there are not many examples of portable or ultra-small ones. The reason for this is that in the former, it is difficult to configure the crankshaft mechanism to be relatively small, the shape of the piston itself is difficult to downsize due to the relationship with the connecting rod small end, and noise and mechanical vibration are large. Also,
This is because in the latter case, it is difficult to achieve high pressure.

[0003]

A commercially available linear motor drive type one-stage compression type gas compressor is compact, but even if the working fluid (hereinafter referred to as fluid) is air, atmospheric pressure to 3 atm ( It was difficult to compress more efficiently than the absolute pressure. In particular, the discharge pressure is low and it cannot be used for paint coating, air supply for automobile tires and air brakes. Further, the flow rate tends to be insufficient even in a septic tank requiring a long pipe, and since it is a single cylinder, mechanical vibration and noise are very large. The present invention is a compressor that eliminates the above-mentioned defects, in which two convex pistons of the same size are arranged in opposition to each other, and both of them synchronously perform compression work in each double action, so that a mechanical balance is achieved. Good and extremely low vibration (around 2 to 3 microns on the side of the body)
・ Low noise (60db or less), high reliability, simple structure with few parts, composed of almost two sets of common parts, and parts are machined and assembled on a concentric shaft, resulting in high machine accuracy. The purpose is to provide a small gas compressor that is inexpensive and has stable performance and low noise and mechanical vibration because it can be made high.

[0004]

SUMMARY OF THE INVENTION The present invention provides two convex movable pistons which are synchronously reciprocated by a reciprocating means on a concentric shaft. And a high pressure compression space for compressing medium pressure to high pressure is formed by a portion surrounded by the top end portion and a fixed cylinder into which the top end portion is fitted, and Two medium pressure cylinders are formed inside the bottom ends of the two convex movable pistons having a relatively large diameter, and medium pressure compression space portions for compressing low pressure to medium pressure are formed by the medium pressure cylinders. Therefore, two convex fixed pistons that are respectively fitted to the intermediate pressure cylinders are provided, and the two convex fixed pistons have a low pressure suction valve and a one-way valve for medium pressure discharge port that are connected to the low pressure suction port. Each has a medium pressure discharge port, and one for the medium pressure discharge port A suction port plug having a medium pressure buffer tank for collecting the medium pressure fluid flowing through the medium pressure passage communicating with the medium pressure passage, and the medium pressure fluid introduced into the medium pressure buffer tank to the high pressure compression space portion. An opposed piston type compression characterized by comprising a high pressure discharge valve for discharging a high pressure fluid from the high pressure compression space section, and a high pressure section plug having a high pressure buffer tank and a high pressure discharge port. The machine is trying to solve this.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The structure of the present invention is mainly composed of a main body, 2
Convex convex movable pistons 2, 2 convex fixed pistons 3,
The suction part plug 14, the high pressure part plug 20, the reciprocating means, the elastic supporting means, and various valves, which form two medium pressure compression space portions 6 and one high pressure compression space portion 5 and a fluid passage communicating with them. However, the two-stage compression type high-efficiency gas compressor is constituted by the intermediate-pressure compression space portion and the high-pressure compression space portion.

The details of the structure of the present invention will be described below with reference to FIGS. 1, 2, 3, 4 and 5 which are sectional views of an embodiment of the present invention. The main body 12 of the compressor 1 has a cooling fin 3 on its outer peripheral portion.
4, the fixed cylinder 4 is formed at the center of the longitudinal center, and the suction plug 14 and the intermediate pressure suction valve 16 and the intermediate pressure suction valve 16 are provided at diametrically symmetrical positions of the portion 121 that constitutes the fixed cylinder 4. The high-pressure part plug 20 and the high-pressure discharge valve 19 are built in, and the inner diameters 123 on both sides in the axial direction constitute a back space part that is concentrically opened to the outside. Inner diameter 12
3 is provided with a sleeve or coating 122 made of an oil-free sliding material. In addition, the fixed cylinder 4 penetrates the inner diameter 123 and the sleeve or coating 122.
Fluid passages 17 and 18 are provided to connect the medium pressure suction valve 16 and the high pressure discharge valve 19 with each other. When the reciprocating means is a linear motor, the stator portion of the linear motor is fixed to the inner diameter 123. The medium pressure suction valve 16 and the high pressure discharge valve 19 may be any one-way valves that are compact, but those using a reed valve, those using a ball / spring, etc. are suitable. Al alloy is mainly used as the material of the main body 12.

The two convex movable pistons 2 have a top end 201 having a relatively small diameter and a bottom end 202 having a relatively large diameter, and the top ends are fitted to the fixed cylinder 4. The movable piston portion 203, and the bottom end portion 2
The inside of 02 forms a movable cylinder portion 204. Further, when the reciprocating means is a linear motor, the outer peripheral portion 205 of the bottom end portion is configured as an armature portion of the linear motor. Al alloy is mainly used as the material of the convex movable piston. Further, the problem of gas tightness in each compression portion directly affects the efficiency of the present invention, and is between the piston and the cylinder, particularly the piston portion 20 of the convex movable piston 2.
It is necessary that the clearance between the fixed cylinder 1 and the fixed cylinder 4 is minimized. For this, the piston part 2
01 and the fixed cylinder 4 are required to have a precise fitting accuracy.
The fitting clearance needs to be accurately finished to about 0.005 to 0.015 mm. It is also possible to improve the gas tightness by providing the labyrinth seal or the seal ring groove 30 in the piston portion 201 and inserting the seal ring 31. In this case, the seal ring is an oil-free type seal ring, and as the material, a tetrafluoroethylene resin containing a filler, a polyimide resin, a polyamide resin, or the like is used.

The two convex fixed pistons 3 are composed of a fixed piston portion 301 and a flange portion 302, and the outer circumference of the fixed piston portion 301 is fitted to the inner diameter of the movable cylinder portion 204 of the convex movable piston 2. ing. Inside the fixed piston portion 301, there are provided a low pressure suction port 9 for supplying a fluid to the intermediate pressure compression space portion 6 and an intermediate pressure discharge port 10 for guiding the intermediate pressure fluid compressed and pressurized in the intermediate pressure compression space portion 6. Has been. The medium pressure discharge port 10 is communicated with the suction plug 14 through the medium pressure discharge port one-way valve 11 and the passages 308 and 310 connected to the medium pressure discharge port 10. The medium pressure outlet one-way valve 11 may be any one-way valve that is compact, but one using a ball / spring is suitable. The low-pressure inlet 9 is connected to an external filter (not shown), a surge tank, and a low-pressure fluid pipe via a one-way valve. 309 is the passage 308
It is a blind plug with a hole for processing. The fitting portion 30 is provided so that the body 12 is sufficiently sealed by the O-ring 26.
It is fitted by 6 and is engaged by a screw or the like. Reference numeral 313 is a hermetic seal for the lead wire 312 to the coil of the linear motor.

An electromagnetic induction type or synchronous type linear motor is most suitable as the reciprocating means. The stator portion 7 composed of a coil for a linear motor, a yoke, a permanent magnet, etc. is fixed to the inner diameter 123 of the main body 12, and the coil 23 or the like is attached to the outer peripheral portion 205 of the bottom end portion of the convex movable piston 2 at a position corresponding thereto. The convex movable piston 2 is reciprocally moved with respect to the stator portion 7 by winding an alternating current in the armature portion of the linear motor, that is, in the intermediate pressure compression space portion 6 and the high pressure compression space portion 5. Gives a compressive movement. The alternating frequency depends on the compression ratio and the specific heat ratio of the fluid, but when He gas is expected to have a pressure of 20 atm or higher, the frequency is set to about 20-30 Hz by the inverter, but normally 50 or 60 Hz by a commercial power source is used Further, as a reciprocating means, it is also possible to use a method in which two electromagnetic magnets are used, and an electric current is alternately supplied to the electromagnetic magnets to reciprocate the convex movable piston 2.

In order to give the reciprocating motion smoothly, the convex movable piston 2 is supported by elastic supporting means. It is important that the elastic support means does not apply an unbalanced thrust load to the axial center of the convex movable piston 2.
A concentric shaft-shaped disc spring made of metal, plastic, composite material or the like as shown in FIGS. 7 and 8 is suitable.
In the case of the corrugated plate spring as shown in FIG. 8, it is necessary to prevent loss work due to the reciprocating motion of the convex movable piston 2 between the fixed cylinder side back space 24 and the fixed piston side back space 25. Therefore, a communication passage 36 is provided, and a fluid is allowed to flow in and out of the communication passage 36, thereby preventing the loss work. In FIG. 8, the communication passage 36 is provided in the disk-shaped spring, but it may be provided anywhere as long as it connects only the back spaces 24 and 25.

Further, the disc-shaped spring shown in FIG. 7 is a spiral disc-shaped spring which is usually used in the cone portion of a dynamic speaker for acoustics and whose center axis is hard to be displaced in the circumferential direction. This is a disc-shaped spring material in which three slits are spirally formed, and has higher flexibility than a corrugated spring. In this case, the communication passage 36 is replaced by the slit.

It is economical and preferable to use a coil spring as the elastic supporting means. The coil spring is composed of a coil spring 28 on the top end side and a coil spring 29 on the bottom end side of the convex movable piston 2, and the coil springs 28 are arranged in a balanced form. Seats 281, 282 and 2
Reference numerals 91 and 292 denote seats for fixing the coil spring 28 and the coil spring 29 at respective positions. In this case, it is desirable to provide a detent to prevent the convex movable piston 2 from rotating in the circumferential direction.

With reference to FIGS. 10 and 1, the operation of the present invention will be described focusing on the flow of fluid. In FIG. 1, the convex movable piston 2 is located at the top dead center, that is, the end of compression, and the volume of the high-pressure compression space 5 is minimum. The gap between the two convex movable pistons in this state is about 0.1.
~ 1 mm, compression specifications (fluid type, working pressure,
Flow rate). At this top dead center, the high-pressure fluid ends the discharge process and then goes to the suction process. At the position of this top dead center, the volume of the medium-pressure compression space 6 formed on the opposite side of the two convex movable pistons is the maximum, and the position where the suction of the low-pressure fluid is completed and the compression process is completed is set. Shows.

By the reciprocating means, the two convex movable pistons 2 are synchronously moved in the separating directions to increase the volume of the high-pressure compression space 5 and suck the medium-pressure fluid, and at the same time, the medium-pressure compression space 6 is drawn. Is reduced to compress the low-pressure fluid, and the medium-pressure fluid whose pressure has been set in advance by the medium-pressure outlet one-way valve is discharged. This process ends at the final amplitude position of the reciprocating motion.

As shown in FIG. 10, the low-pressure fluid has two low-pressure inlets of the compressor of the present invention from a pipe a branched from a filter a and a surge tank b separately provided from the outside. 9 intake valve d (not shown)
Is introduced into the compression section e, which is the compression section e, and is compressed. The medium-pressure fluid compressed in advance to the pressure set by the one-way valve f is radiated by the radiator g by the cooling fins of the main body 12 through the pipe and accumulated in the medium-pressure buffer tank i provided in the suction plug 14. One-way valve j
And is compressed by the high-pressure compression space part 16 which is one compression part k. The compressed fluid is discharged to the outside as a high pressure fluid whose pressure is preset by the one-way valve 1.

That is, the two intermediate-pressure compression spaces 6 are sucked,
The compression and discharge are performed in the same phase, and the one high-pressure compression space 5 and the intermediate-pressure compression space 6 perform suction, compression, and discharge processes with a phase difference of 180 degrees. For this reason, the two convex movable pistons 2 perform the same work in a balanced manner on the concentric shafts in a synchronously and double-acting manner, so that the contact pressure with which the piston portion 201 contacts the fixed cylinder 4 is extremely small, and vibration does not occur. Extremely small. In addition, by using a linear motor that is simple and has the same shape and has a small number of parts, vibration noise is extremely reduced.

The main specifications of the present invention for carrying out the above operation are as follows. a) Working fluid: Air, nitrogen, argon, helium, neon and other mixed gases b) Discharge pressure: 3 to 20 atm c) Reciprocating frequency: 10 to 60 Hz d) Reciprocating amplitude: 3 to 10 mm e) Convex movable piston Top end diameter: 10 to 25 mm In addition, about the reciprocating frequency, about 20 Hz is required for the specification of 20 atm with helium, and the commercial frequency is 5
It is given by the inverter from 0 and 60 Hz. Also 2
The amount of clearance at the top dead center between the two convex movable pistons is 0.1 to 1 mm in design.

In the compressor of the present invention, it is necessary to accurately measure the amplitude of the convex movable piston and the amount of clearance at the top dead center due to the influence of various resistances. For this reason,
The amount of reciprocating motion is measured in advance by an experiment using an actual machine using an electromagnetic displacement measuring device as shown in FIG. Reference numeral 32 is a magnetic pin for an electromagnetic displacement measuring device attached to the bottom portion 208 of the convex movable piston, and 33 is the top portion 3 of the convex fixed piston.
This is a solenoid for the electromagnetic displacement measuring instrument built in 04. In practical use, this electromagnetic displacement measuring device is removed.

[0019]

The opposed piston type compressor of the present invention has an extremely smaller number of parts than the conventional crankshaft type two-stage compressor, and has a simple structure in which two sets of parts having the same shape and size are used. Therefore, it is easy to process and assemble with high precision and can be manufactured at low cost. Two convex pistons of the same size are arranged in the opposite type, and both sides perform double-compression work, resulting in a mechanical balance. Good, extremely low vibration (2 on the side of the body
It has the effect of guaranteeing high reliability with low noise (60db or less).

[Brief description of the drawings]

FIG. 1 is a sectional view of one embodiment of the present invention.

FIG. 2 is a side view showing an embodiment of the present invention.

FIG. 3 is a sectional view of a convex movable piston according to an embodiment of the present invention.

FIG. 4 is a sectional view of a convex fixed piston according to an embodiment of the present invention.

FIG. 5 is a cross-sectional view of a main body portion according to an embodiment of the present invention.

FIG. 6 is a plan view of one elastic supporting means used in the present invention.

7a is a plan view of another elastic supporting means used in the present invention. FIG. b A sectional view taken along line AA of another elastic supporting means used in the present invention.

FIG. 8 is a partial cross-sectional conceptual view of a case where a coil spring is used as the elastic support means and a seal ring is applied to the convex fixed piston portion in the present invention.

FIG. 9 is a partial cross-sectional conceptual view showing a state in which a reciprocating displacement measuring device is attached to the present invention.

FIG. 10 is an explanatory diagram showing an operation flow of a compressed fluid in the present invention.

[Explanation of symbols]

 1 Opposed Piston Compressor 2 Convex Movable Piston 3 Convex Fixed Piston 4 Fixed Cylinder 5 High Pressure Compression Space 6 Medium Pressure Compression Space 7 Linear Motor Stator 8 Elastic Support Means 9 Low Pressure Suction Port (Suction Valve Not Shown) 10 Medium Pressure Discharge Port 11 Medium Pressure Discharge Port One-way Valve 12 Main Body 13 Medium Pressure Passage 14 Suction Port Plug 15 Medium Pressure Buffer Tank 16 Medium Pressure Suction Valve 17 Medium Pressure Suction Passage 18 High Pressure Discharge Passage 19 High Pressure Discharge Valve 20 High Pressure Plug 21 High Pressure Buffer tank 22 High-pressure discharge port 23 Electromagnetic coil for linear motor 24 Fixed cylinder side backspace 25 Fixed piston side backspace 26 O-ring 27 O-ring 28 Coil spring (1) 29 Coil spring (2) 30 Seal ring groove 31 Seal Ring 32 Magnetic pin for displacement measurement 33 Detection for displacement measurement 34 cooling fins 35 setscrew 36 communicating path

Claims (6)

[Claims] 1. Two convex movable pistons, which are synchronously reciprocated by a reciprocating means on a concentric shaft, are arranged such that their top ends having relatively small diameters face each other on the concentric shaft. Then, a high pressure compression space portion for compressing an intermediate pressure to a high pressure is formed by a portion surrounded by the top end portion and a fixed cylinder into which the top end portion is fitted, and the two convex movable pistons The medium pressure cylinders are formed inside the bottom end portion having a relatively large diameter, and the medium pressure cylinders are used to form the medium pressure compression spaces for compressing low pressure to medium pressure. Two convex fixed pistons that are fitted to each other are provided, and each of the two convex fixed pistons is provided with a low pressure suction valve connected to the low pressure suction port and a medium pressure discharge port having a one-way valve for medium pressure discharge port. Flow through a medium pressure passage communicating with the one-way valve for medium pressure discharge port. A medium-pressure buffer tank for collecting the medium-pressure fluid, and a medium-pressure suction valve for introducing the medium-pressure fluid introduced into the medium-pressure buffer tank into the high-pressure compression space. An opposed-piston compressor, further comprising a high-pressure discharge valve for discharging a high-pressure fluid from the high-pressure compression space, and a high-pressure plug having a high-pressure buffer tank and a high-pressure discharge port. 2. An armature of a linear motor, wherein the reciprocating means has a coil or / and a permanent magnet attached to a portion having a relatively large diameter of the two convex movable pistons.
2. The opposed piston type compressor according to claim 1, which is a linear motor having a solenoid or / and a permanent magnet provided concentrically on the inner surface side of the main body so as to face the armature, as a stator portion of the linear motor. 3. The opposed piston type compressor according to claim 1, wherein the two convex movable pistons are supported by elastic supporting means. 4. The diameter of the two convex movable pistons is 1
It is 0-25 mm, The opposed piston type compressor of any one of Claim 1 thru | or 3 characterized by the above-mentioned. 5. The number of reciprocating cycles is 10 to 60.
The opposed piston compressor according to any one of claims 1 to 4, wherein Hz and amplitude are 3 to 10 mm. 6. The opposed piston type compressor according to claim 3, wherein the elastic supporting means is a disk spring.