JPH02286891A - Rotary compressor - Google Patents

Abstract

PURPOSE:To enable a stable operation for a long period of time by forming at least one of the slide parts of a rotary sleeve and vanes from porous silicon carbide filled with lubricant. CONSTITUTION:With rotation of an eccentric rotor 3 the fluid sucked in from a suction hole 5 boosts the fluid pressure in a chamber 7 while continuously decreasing its capacity gradually, wherein the compression chamber 7 is formed from a rotary sleeve 2, a rotor 3 and vanes 4. It is then exhausted from a fluid exhaust port 6 as a compressed fluid. Centrifugal force due to rotation of the rotor 3 protrudes the vanes 4 from the rotor 3 to cause their contacting the sleeve 2, and the friction force in between will rotate the sleeve 2. Therein at least the sleeve 2 and vanes 4 are made of porous silicon carbide, and voids in them are filled with lubricant to provide self-lubricating property. This enhances resistance against wear and thermal shock, and wear due to friction is lessened at starting, under high load operation, and at transient until single- piece rotation is attained with sleeve 2 and vanes 4.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a vane-type rotary compressor used in vehicle air conditioners, combustion pressure pumps, blowers, vacuum pumps, portable compressors, etc. of diesel automobiles.

[Conventional technology]

A vane-type rotary compressor has multiple vanes inserted into and out of a rotor that rotates eccentrically within a casing. Each vane moves in and out sequentially as the rotor rotates, producing compressed fluid. It is.

Therefore, among the parts constituting the compressor, the casing and vanes, which are the parts that directly compress the compressed fluid, are important, and wear of the casing and vanes causes a reduction in compression capacity. For this reason, the casings and vanes have conventionally been made of special alloys such as high-tensile steel or manganese steel, which have excellent wear resistance, or have been made of graphite material.

Furthermore, as one measure against wear, a structure has been disclosed in which a rotary sleeve of cylindrical shape is provided in the casing so as to be freely rotatable so as to be in contact with the tip of the vane, thereby reducing wear. That is, since this rotating sleeve is made of wear-resistant metal like the casing and is arranged to be rotatable, it rotates with the rotation of the vanes attached to the rotor, so sliding wear is reduced. It has a structure.

In addition, in order for the rotating sleeve to rotate integrally with the rotor, it is necessary to reduce the resistance between the casing and the rotating sleeve, so lubricating oil is introduced into the gap between the casing and the rotating sleeve, or a gas bearing is used. things were being done.

[Problem that the invention seeks to solve]

However, even in such a structure, the rotating sleeve and vane cannot rotate completely as one unit at all times, but rather rotate relative to each other, especially during startup, high load, or from startup to steady state. Under operating conditions such as during transient periods, wear cannot be completely prevented, and these parts are still required to have wear resistance and lubricity.

On the other hand, in the case of the method of introducing lubricating oil between the casing and the rotating sleeve, the gap between the rotating sleeve and the casing is filled, which increases the resistance of the lubricating oil itself and may cause oil leakage. Ta. Also,
For example, if grooves are formed on the outer surface of the rotating sleeve and a gas bearing is used, the effect of the gas bearing will be reduced during steady operation, but the gas bearing will not function sufficiently during startup, high loads, or transient situations. As a result, the rotating sleeve comes into abnormal contact with the casing or vane, causing heat generation and seizure, resulting in a reduction in compression capacity and even damage.

From the above, the problem to be solved by the present invention is not the wear or contact resistance during steady operation, but rather the problem of
The present invention is based on the fact that reduction in compressor performance due to wear and tear or resistance caused by contact during high loads or transient periods from startup to steady operation has a negative impact on the long-term performance and life of the compressor. The purpose of this invention is to prevent the wear, seizure, or increase in resistance even if abnormal contact occurs, and to provide a compressor that can operate stably for a long period of time.

[Means for solving problems]

In order to solve the above-mentioned problems, the means taken by the present invention is such that the rotary sleeve is rotatably fitted into a cylindrical casing and the eccentric rotor is retractably inserted into the rotary sleeve so that the inner surface slides into contact with the rotary sleeve. In the rotary compressor, at least one of the sliding contact portions between the rotary sleeve and the vanes is formed of a porous silicon carbide body filled with a lubricant.

Furthermore, in the rotary compressor, at least one of the opposing surfaces of the rotary sleeve and the casing is formed of a porous silicon carbide body filled with a lubricant.

That is, the present invention is designed to prevent the vanes inscribed in the rotating sleeve or the rotating sleeve and the casing from coming into abnormal contact particularly at startup, under high load, or during transient conditions, thereby preventing deterioration of compressor performance due to repeated heat generation, seizure, and wear resistance. A silicon carbide porous body with excellent wear resistance is used for the casing, rotating sleeve, or vane instead of a metal one, and the pores of the silicon carbide porous body are filled with a lubricant, and the lubricant is added as appropriate. The structure allows for supply of just the right amount to the sliding contact area.

In particular, in order to supply lubricant to the sliding contact area between the rotating sleeve and the vane, the pores are filled in advance by controlling the pore diameter and porosity of the porous body, paying attention to the pressure difference during the pressurization process of the compressor, which will be described later. They discovered that the lubricant can be smoothly supplied to the sliding contact area by a pumping action.

Next, its effect will be explained in detail.

FIG. 1 is a sectional view showing a rotary compressor having a rotary sleeve according to the present invention.

FIG. 1 shows a rotating sleeve (2) fitted into a casing (1) and four vanes (4) which are in sliding contact with the rotating sleeve (2) which is retractably inserted into an eccentric rotor (3). It is equipped with

In the figure, (5) is a fluid inlet, and (6) is a fluid outlet. The fluid sucked through the fluid suction port (5) rotates (arrow) of the eccentric rotor (3) and flows through the rotating sleeve (2).
), the eccentric rotor (3), and the vane (4) while successively decreasing the volume of the compression chamber (7).
) in the fluid outlet (6) as compressed fluid.
).

When the rotor (3) rotates, the vanes (4) of the rotating sleeve (2) are projected outward from the rotor (3) due to centrifugal force, contact the rotating sleeve (2), and the rotating sleeve (2) is rotated by the frictional force. will be rotated.

Therefore, in the rotary compressor of the present invention, at least the sliding contact portion between the rotary sleeve (2) and the vane (4) is formed of a porous silicon carbide material. The reason for this is that, as mentioned above, the rotating sleeve (2) rotates while slidingly contacting the vane (4), and the sliding contact portion is required to have wear resistance and airtightness. That is, during startup, high load, and transient times, considerable wear due to friction occurs until the rotary sleeve (2) and vane (4) rotate integrally. Also, during startup, between the casing (1) and the rotating sleeve (2),
During high loads and transients, abnormal contact occurs and friction occurs.
The rotating sleeve (2) is required to be wear resistant since it will be subject to resistance. For this reason, it is advantageous to use ceramics as a wear-resistant material in the compressor of the present invention, which has higher hardness and wear resistance than metals or plastics, and has particularly good wear resistance and thermal shock resistance. Silicon carbide is used because it has excellent properties and has low attackability against opposing materials. Furthermore, in the present invention, it is preferable that the silicon carbide is made into a porous material and the pores are filled with a lubricant. Although it has excellent wear resistance by itself, it has the disadvantage of a relatively large wear coefficient, so it can be made self-lubricating by making the ceramic porous and filling the open pores with a lubricant. It is from. Moreover, by making the rotary sleeve (2) a porous material, the weight of the rotary sleeve (2) can be reduced, and the power loss of the compressor can be reduced.

The reason why the silicon carbide porous body filled with the lubricant is used in the rotary sleeve (2) or vane (4) of the rotary compressor of the present invention is that This is because when this is used, the lubricant contained in the porous body is subjected to an appropriate pressure difference during operation, so-called pumping action, and seeps into the sliding portion, allowing smooth rotation.

That is, as shown in the figure, the inflow fluid satisfies P + < P z < P 3 < P 1 in the compression chamber (7).
Since the pressure increase and decrease are repeated in sequence, at least the inner surfaces of the members constituting the compression chamber, such as the rotating sleeve (2) @ rotating rotor (3) and vane (4), are covered with the P+, Pg, and P.
The member is subjected to a pressure of s at each stage, and the member is constantly subjected to a pumping action in response to pressure changes at each stage. From this, lubricant can be appropriately and continuously supplied to the sliding parts without impairing lubricity.

Further, it is preferable that at least one of the opposing surfaces of the rotating sleeve and the casing is formed of a porous silicon carbide body filled with a lubricant.

The reason for this is that, as mentioned above, the casing and the rotating sleeve are also required to have wear resistance, impact resistance, and lubricity, just like the sliding contact portion between the rotating sleeve and the vane.

Further, in the compressor of the present invention, it is preferable that a dynamic pressure groove is formed on one of opposing surfaces of the rotating sleeve and the casing.

In other words, if the casing or the rotating sleeve is made of a silicon carbide porous body filled with lubricant and dynamic pressure grooves are formed on either of the opposing surfaces, the contact ratio due to vibration (shaking) during steady operation can be reduced. is reduced by the generation of dynamic pressure, allowing stable operation over a longer period of time.

From the above, it is obvious that in the present invention, the silicon carbide porous body may be used for the casing, the rotating sleeve, or the vane. There is no problem even if they are integrated by joining etc.

In particular, if the rotating sleeve is made of the silicon carbide porous material, it acts on both the surface facing the casing (outer peripheral surface of the rotating sleeve) and the surface facing the vane (inner peripheral surface of the rotating sleeve), and is also easy to manufacture. It is easy and preferable.

Next, a silicon carbide porous body filled with a lubricant will be described.

The porosity of the silicon carbide porous body used in the present invention is 10 to
Preferably, it is 60% by volume. The reason for this is that when the porosity is less than 10% by volume, even when filled with lubricant, the sliding area of the ceramic is larger than the area of the pores that have lubricating properties, so the lubricant is not sufficiently effective. This is because they cannot perform to their full potential.

On the other hand, if the porosity is greater than 60% by volume, the lubricity effect is sufficient, but the strength of the ceramic porous body decreases and the load bearing capacity decreases. It is suitable that it is 20 to 50% by volume.

It goes without saying that the pores are open pores because they are filled with lubricant.

Moreover, it is preferable that the average pore diameter of the porous body is 4 μm or less.

The reason for this is that if the diameter is larger than 4 μm, the lubricant will be discharged from the pores more than necessary due to the above-mentioned bombing effect, which will have an adverse effect and shorten the lubrication life.

The lubricant filled in the open pores of the ceramic porous body is at least one selected from fluorine-based oil, silicone-based oil, mineral oil, animal and vegetable oil, paraffin-based oil, and naphthenic oil. Can be used. These can be easily filled into the pores of the ceramic, react sensitively to slight frictional heat during startup, have a low viscosity, and are supplied to the sliding contact surface between the rotating sleeve and the vane by a pumping effect, This is to significantly reduce the starting torque, and among them, at least L type selected from fluorine oil, silicone oil, paraffin oil, or naphthene oil is more effective.

In addition to the lubricants filled in the open pores of the ceramic porous body as described above, polyacetal resin, polyamide resin, polyethylene resin, polycarbonate resin, polybutylene terephthalate resin, styrene acrylonitrile resin, polypropylene resin, polyurethane At least one selected from resins, silicone resins, and fluorine resins may be used.

The reason why these lubricants can be used is that these resins are solid lubricants with excellent self-lubricating properties, and because they are present in the pores of the ceramic porous body, there is extremely little loss, and they are excellent over a long period of time. This maintains the same sliding properties.

Among these, at least one selected from polyacecool resin, polyamide resin, polyethylene resin, polycarbonate resin, and fluororesin is more effective.

Note that any of the above lubricants may of course be used alone, or oil and resin may be made to coexist in the pores of the ceramic at the same time.

The lubricant contains at least one lubricant in the pores of the ceramic.
Preferably, the filling is 0% by volume.

The reason for this is that if it is less than 10% by volume, it will be difficult to fully exhibit its lubricating effect, and in particular, a content of 30% by volume or more is more effective.

The lubricant can be filled into the pores by heating and melting the lubricant, by dissolving it in a solvent, by filling it with a monomer or a reaction raw material, and then reacting the lubricant by filling the pores with fine particles. There is a method in which the lubricant is suspended or emulsified in a dispersion medium and then dried to remove the dispersion medium. Two or more methods can be used in combination, and it is also possible to charge the lubricant in several batches. You can also do it.

Next, a method for manufacturing a rotary sleeve made of a porous silicon carbide body used as an example in the rotary compressor of the present invention will be described.

In addition, a rotary sleeve in which dynamic pressure grooves are formed on the outer circumference will be described.

After molding the silicon carbide fine powder into a desired ring shape, the resulting formed body was fired at normal pressure and high temperature to form a porous body.

Next, the surface of this porous body was made smooth and flat with few undulations by lamp finishing.

Next, the ring-shaped porous body was washed with trichlene, then washed with a NaOH aqueous solution, and neutralized with dilute sulfuric acid.

Next, in order to form dynamic pressure grooves on the outer periphery, a liquid photosensitive resin is applied after adjusting the viscosity with a solvent, and preliminary curing (100'C) is repeated to form a photosensitive resin film of the desired thickness on the surface. A pattern film with a pattern was applied and exposed, the uncured portions (grooves) were removed with a developer, and grooves were formed by shot blasting. Incidentally, when performing shot blasting, it is a matter of course that areas other than the desired portions (grooves) are covered with a mask material to prevent blasting.

Next, the resin film was removed with a stripping solution to complete the formation of the dynamic pressure grooves. The dynamic pressure groove formed in this manner has a sharp uneven pattern and can function highly as a gas bearing.

The ring-shaped porous body formed as described above was filled by immersing it in fluorinated oil whose viscosity had been reduced by heating. The fluorine oil filling amount accounted for about 40% of the open pores in the porous body.

〔Effect of the invention〕

The rotary compressor of the present invention uses a silicon carbide porous body filled with lubricant on the opposing surfaces of the casing and the rotary sleeve and the sliding contact portions of the vane and the rotary sleeve, so that when starting up,
Even if the casing, rotating sleeve, and vane come into abnormal contact during high loads or during transitions from startup to steady state, wear can be prevented, and the lubricant can also reduce resistance.

Further, by forming a dynamic pressure groove on one of the facing surfaces of the casing and the rotating sleeve to form a gas bearing, smoother operation can be achieved.

In addition, the lubricant controls the porosity and pore diameter of the silicon carbide porous body and defines the filling amount, and also exerts a lubricating effect in just the right amount during operation by utilizing the pumping effect due to the pressure difference within the compressor. This can prevent abnormal heat generation and burn-in.

As a result of the above, wear resistance and lubricant are not lost from the time of start to the time of stop (compared to conventional compressors, there are fewer rotational failures and it is stable over a long period of time).

[Brief explanation of drawings]

The figure is a sectional view of a main part of a rotary compressor according to an embodiment of the present invention. Rotating sleeve 3 made of porous silicon carbide filled with casing lubricant - Rotating rotor 4 - - - 1111 - Vane 5 - - 111 Fluid Inflow port 6 ----1...Fluid discharge lower ----1---Compression chamber 8------1---Dynamic pressure groove

Claims (1)

[Scope of Claims] 1) A rotary compressor comprising: a rotating sleeve rotatably fitted into a cylindrical casing; and a vane inserted retractably into an eccentric rotor so as to be in sliding contact with the inner surface of the rotating sleeve. In the rotary compressor, at least one of the sliding contact portions between the rotary sleeve and the vane is formed of a porous silicon carbide body filled with a lubricant. 2) The rotary compressor according to claim 1, wherein at least one of the opposing surfaces of the rotary sleeve and the casing is formed of a porous silicon carbide body filled with a lubricant. 3) The rotary compressor according to claim 1 or 2, wherein a dynamic pressure groove is formed on one of opposing surfaces of the rotary sleeve and the casing. 4) The silicon carbide porous body has a porosity of 10 to 60% by volume,
The rotary compressor according to claims 1 and 2, wherein the pore diameter is 4 μm or less.