JPH064066Y2 - Rotary compressor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a rotary compressor using helium gas as a gas to be compressed.

(Prior Art) A helium refrigeration system using helium as a refrigerant is
Since cryogenic temperatures of 200 ° C or lower can be easily obtained, it has been used for cryogenic temperatures.

In this helium refrigeration system, a rotary compressor having a structure as shown in FIGS. 6 and 7 has been used.

That is, the rotary compressor main body 2 is arranged in a casing 1 that serves as a high-pressure dome. The compressor body 2
Is a cylindrical cylinder 3, cylinder heads 4 and 4 that cover both sides of the cylinder 3, a rotor 6 that eccentrically rotates inside the cylinder 3 by a driving force of a motor 5, an inner peripheral surface of the cylinder 3, and a rotor 6. A helium gas X that is provided with a blade 9 that divides the space between the outer peripheral surface into an intake chamber 7 and a discharge chamber 8 and is drawn from an intake port 10 that opens to the intake chamber 7.
Is compressed and then discharged into the casing 1 from a discharge port 11 opening to the discharge chamber 8. Reference numeral 17 is a discharge valve, and 19 is a blade groove.

On the other hand, since the thermal insulation coefficient of helium gas is K = 1.66, which is higher than that of chlorofluorocarbon gas, etc., when used at a compression ratio of 2 to 4, the helium gas sucked at 30 ° C will cause 200 ° C on the discharge side. More than that.

As a result, in a compressor that uses helium gas as a gas to be compressed, problems such as poor lubrication due to a decrease in oil viscosity due to high temperature, deterioration of oil due to a high temperature, and breakage of a compressor discharge valve occur.

Therefore, oil injection is performed to cool the helium gas during compression. That is, heat is exchanged with the oil coil 12 in the process of flowing the oil coil 12 wound around the outer surface of the casing 1 with lubricating oil A (hereinafter abbreviated as oil) in a high pressure atmosphere stored in the oil reservoir 20 at the bottom of the casing 1. Cooling water coil wound around the outer surface of the casing 1 if possible
After cooling from about 100 ° C. to about 30 ° C. by 13 and by injecting into the helium gas in the suction pipe 15 through the orifice 14, the temperature on the discharge side of the compressor is 120 to 130.
It was designed so that the temperature could be lowered to about ℃ (Application No. 59-18451).
No.).

In the rotary compressor used for air conditioning and using Freon gas as the compressed gas, as shown in FIG.
On the inner peripheral surface of the cylinder 3, the discharge port 11 and the blade 9
It is known that a recess 16 for preventing oil confinement (that is, oil compression) in the final stage of the discharge stroke is provided between the above and the above (see, for example, Japanese Utility Model Laid-Open No. 58-66195).

(Problems to be solved by the invention) When the rotary compressor having the above-mentioned configuration is used for helium gas compression, oil is injected into the intake helium gas, so that the amount of oil supply increases and the end of the discharge stroke increases. In the stage, oil compression occurred, and the collision speed of the discharge valve 17 against the valve seat (the speed at which the valve opened and then closed rapidly) increased abnormally, possibly causing valve cracking. Since the amount of oil supplied to the helium gas as the refrigerant is much larger than that of the ordinary chlorofluorocarbon gas, the oil compression cannot be prevented by the accommodation amount of the recess 16 disclosed in the known example.

Further, as shown in FIG. 9, the crank rotation angle θ = 330 ° ± 10 ° at the crank rotation angle θ = 330 ° ± 10 °, as is apparent from the changes in the internal pressure Pc of the cylinder 3, the valve speed V of the discharge valve 17, and the valve behavior H with respect to the crank rotation angle θ. Oil compression is occurring.

The present invention has been made based on the above facts, and an object of the present invention is to prevent oil compression in a rotary compressor by allowing the oil in the discharge chamber to escape to the suction chamber at the final stage of the discharge stroke. It is what

(Means for Solving Problems) As a means for solving the above problems, the present invention provides a rotary compressor that uses helium gas as a compressed gas, and a discharge port formed on the inner peripheral surface of the cylinder 3. Rotor 6 to 11
Rotation angle θ of the rotor 6 before the sliding contact
A groove-shaped oil escape passage 18 extending in the inner peripheral direction of the cylinder (3) that connects the discharge chamber 8 and the suction chamber 7 at = 330 ° ± 10 ° is provided.

(Operation) In the present invention, the following operations can be obtained by the above means.

That is, in the final stage of the discharge stroke, the gas cooling oil sucked together with the sucked helium gas is discharged from the discharge chamber 8 side to the suction chamber 7 side through the groove-shaped oil escape passage 18 before being compressed. , Prevent oil compression from occurring.

Embodiments Hereinafter, some preferred embodiments of the present invention will be described with reference to the accompanying drawings.

Example 1. FIG. 1 is an enlarged view of a main part of a compressor according to a first embodiment of the present invention.

The entire structure of the rotary compressor of this embodiment is the same as the sixth embodiment described above.
Since it is the same as that shown in FIG. 7 and FIG. 7, detailed description thereof will be omitted to avoid duplication.

In the present embodiment, the oil escape passage 18 that connects the discharge chamber 8 and the suction chamber 7 is formed in the cylinder 3 at the final stage of the discharge stroke.

That is, the oil escape passage 18 is formed between the discharge port 11 and the crank rotation angle θ = 330 ° ± 5 ° before the rotor 6 slidably contacts the discharge port 11 in the cylinder 3. It is composed of a notch groove 18d. Then, when the rotation of the rotor 6 is at the crank rotation angle θ = 330 ° ± 5 °, that is, at the final stage of the discharge process when the discharge of the helium gas is almost completed, the end of the cutout groove 18d is moved to the suction chamber 7
The oil remaining in the discharge chamber 8 is discharged to the suction chamber 7 through the discharge port 11 and the cutout groove 18d.

Therefore, in the final stage of the discharge process, oil compression that may have occurred is prevented in advance.
The collision speed of 17 is greatly reduced. This is clear by comparing FIG. 9 (conventional example) and FIG. 10 (this embodiment) showing changes in the cylinder internal pressure Pc, the discharge valve speed V and the discharge valve behavior H with respect to the crank rotation angle θ. Let's do it. In particular, comparing V _{1 in} FIG. 9 with V _{1 in} FIG. 10 shows that the collision speed is greatly reduced.

Example 2. In the case of the second embodiment illustrated in FIGS. 3 and 4, the oil release passage 18 has a crank rotation angle θ = before the rotor 6 is slidably contacted with the discharge port 11 on the inner peripheral surface of the cylinder 3.
It is constituted by a notch groove 18e formed between the discharge port 11 and the blade 9 and a recess 16 formed at a position of 330 ° ± 5 °. In this case, when the rotation of the rotor 6 exceeds the crank rotation angle θ = 330 ° ± 5 °, the end of the cutout groove 18e is opened to the suction chamber 7 side, and the oil remaining in the discharge chamber 8 is dented. Suction chamber 7 through place 16 and notch groove 18e
Is discharged to.

Example 3. In the case of the third embodiment shown in FIG. 5, the oil escape passage 18 is provided on the inner surface of the cylinder head 4 at the discharge port 11 and at the rotor 6.
Crank rotation angle θ = 330 ° ±
Notch groove 18 formed between the 5 ° position and the discharge port 11
It is composed of f. In this case, when the rotation of the rotor 6 exceeds the crank rotation angle θ = 330 ° ± 5 °, the cutout groove 1
The end of 8f is opened to the suction chamber 7 side, and the oil remaining in the discharge chamber 8 is discharged to the suction chamber 7 through the discharge port 11 and the cutout groove 18f.

It should be noted that the present invention is not limited to each of the above-described embodiments, and it goes without saying that the design can be changed without departing from the scope of the invention, and in each of the above-described embodiments, the oil escape passage 18 has the crank rotation angle θ. Although it has been described that it is provided at the most preferable angle of 330 ° ± 5 °, even if the crank rotation angle θ is set at 330 ° ± 10 °, the same operation as the former is achieved.

(Effect of the Invention) As described above, according to the present invention, in the rotary compressor in which helium gas is used as the gas to be compressed and the helium gas is cooled by the oil injection to the suction side, the discharge port 11 Before the rotor 6 is slidably contacted with, the oil release passage 18 that connects the discharge chamber 8 and the suction chamber 7 is attached at the crank rotation angle θ = 330 ° ± 10 °, and at the final stage of the discharge stroke. Since the gas cooling oil sucked with the suction helium gas is discharged from the discharge chamber 8 side to the suction chamber 7 side before the oil compression is performed, the oil compression is prevented in advance, and as a result, the discharge valve There is a practical effect that the collision speed of 17 is greatly reduced, and a highly reliable rotary compressor that is free from the risk of failure such as valve cracking can be provided.

Further, since the oil on the discharge chamber 8 side is allowed to escape to the suction chamber 7 side via the oil escape passage 18 before the rotor 6 slidably contacts the discharge port 11, the oil is discharged promptly and the residual oil is left. There is also an effect that oil compression by oil can be effectively prevented.

Further, since the oil is to be discharged into the suction chamber 7, most of it is discharged as gas and the amount of residual oil can be reduced and the dead space can be reduced. Therefore, there is also an advantage that the compression efficiency is not deteriorated.

Further, since the oil escape passage 18 is a groove-like passage extending in the inner circumferential direction of the cylinder 3, the oil in the discharge chamber 8 is continuously sent to the suction chamber 7 side as the rotor 6 rotates, so that the oil amount is increased. At most, you can surely release the oil.

[Brief description of drawings]

FIG. 1 is an enlarged view of essential parts of a rotary compressor according to Embodiment 1 of the present invention, and FIG. 3 is an enlarged view of essential parts of a rotary compressor according to Embodiment 2 of the present invention, FIGS. 1 is a perspective view of a cylinder portion in FIGS. 1 and 3, FIG. 5 is an inner view of a cylinder head in a rotary compressor according to a third embodiment of the present invention, and FIGS. 6 and 7 are general views. FIG. 8 is a longitudinal sectional view and a transverse sectional view of the rotary compressor for helium, FIG. 8 is a view corresponding to FIG. 1 of a conventionally known rotary compressor, and FIGS. 9 and 10 are conventional examples and embodiments of the present invention. FIG. 7 is a characteristic diagram showing changes in cylinder internal pressure Pc, discharge valve valve speed V, and valve behavior H with respect to a crank rotation angle θ of a rotor. 3 ... Cylinder 4 ... Cylinder head 6 ... Rotor 7 ... Suction chamber 8 ... Discharge chamber 9 ... Blade 18 ... Oil escape passage

 ─────────────────────────────────────────────────── ─── Continuation of the front page Judge Naoki Iizuka (56) References JP-A-55-98687 (JP, A) SAIKAI 58-66195 (JP, U)

Claims (1)

[Scope of utility model registration request] 1. A cylindrical cylinder (3), and a pair of cylinder heads (4) covering both sides of the cylinder (3).
(4) and the rotor (6) that eccentrically rotates inside the cylinder (3), and the space between the inner peripheral surface of the cylinder (3) and the outer peripheral surface of the rotor (6) into a suction chamber (7) and a discharge chamber (8). ) And a blade (9) for partitioning the helium gas into the cylinder (3) or the cylinder head (cylinder head (3) to cool the helium gas used as a compressed gas by oil injection to the suction side. 4) On the inner surface, the discharge port (1) formed on the inner peripheral surface of the cylinder (3).
A cylinder for communicating the discharge chamber (8) with the suction chamber (7) at a crank rotation angle θ = 330 ° ± 10 ° of the rotor (6) before the rotor (6) is slidably contacted with the rotor (6). (3)
A rotary compressor having a groove-shaped oil escape passage (18) extending in the inner peripheral direction of the rotary compressor.