JP2997333B2 - Oil-cooled screw compressor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil-cooled screw compressor, and more particularly, to an improvement in a rotor of an oil-cooled screw compression engine.

[0002]

2. Description of the Related Art An oil-cooled screw compressor that drives a male rotor without using a timing gear supplies oil to the suction side or between the rotors to cool the compression heat. At the same time, the oil that has entered the engagement surface with the rotor prevents direct contact between the rotor tooth surfaces. However, the rotor tooth has a tooth shape,
There are errors in indexing, indexing, etc., meshing is not performed smoothly, and oil is diluted by refrigerant depending on operating conditions, so oil on the rotor tooth surface runs out, It is inevitable that noise will occur due to direct contact between metal surfaces.

In order to prevent this noise, for example, Japanese Utility Model Laid-Open No. 51-62110 and Japanese Utility Model Laid-Open No. 52-14221
No. 8 discloses a resin core having heat resistance and abrasion resistance.
A screw compressor is described in which a coating or the like is applied to the tooth surface of the rotor, and a small gap between the tooth surfaces is filled by coating to prevent direct contact between metal surfaces. Have been.

[0004]

However, in such a motor, the coating is easily peeled off due to the relative slip of the rotor, and the effect is lost within a short period of time.
Noise increases.

An object of the present invention is to provide an oil-cooled screw compressor that can suppress generation of noise for a long period of time.

[0006]

Means for Solving the Problems To achieve the above object, the present invention relates to a refueling screw compressor,
A plurality of hemispherical teeth are provided on the tooth surface,
Forming depressions and retaining the oil by these depressions
It was to so.

[0007]

[0008]

[Action] When oil is supplied between the suction port and the rotor,
The supplied oil cools the compression heat while entering the intermeshing surfaces of the rotors to form an oil film on the rotor surface, thereby preventing the rotor from coming into direct contact. The formed oil film retains the oil that has entered between the rotor and the rotor, so that it is maintained even if there is an error in tooth profile, lead, indexing error or the like.

When the depression has a hemispherical shape, the depression can be processed by the shot blast method. At this time, if the depression is provided only on the tooth surface of the female rotor, the projected shot is prevented from escaping from the tooth surface by the peaks forming the tooth surface.
Processing can be performed easily. In addition, if the recess is provided only in the area which becomes the advancing surface in the female side rotor, not only can it be processed by the shot blast method, but also a rolling roller having a complementary shape to the female side rotor. As a result, the depression can be formed, so that the processing can be performed in a shorter time and the depression of an arbitrary form can be obtained.

Further, if the recess is provided including a region on the discharge side and a region on the suction side of the rotor, for example, the entire tooth surface of the female side rotor or the female side rotor is provided. If the oil film is provided in the region of the rotor on the advance side and the suction side of the tooth surface, or in the region of the female rotor on the advance side and the discharge side of the tooth surface, an oil film is formed on the discharge side and the rotor side of the rotor. Also formed on the suction side, it is possible to prevent the gas compressed by the rotor from these parts from leaking, so that the compression performance can be improved.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an oil-cooled screw compressor according to the present invention will be described below with reference to FIGS.

As shown in FIG. 1, the oil-cooled screw compressor includes a compressor body 10, a condenser 11, an expansion valve 12, and an evaporator 13.

The compressor body 10 includes a casing body 20, an inner cover 21 and two outer covers 2 for casing.
2, 23. The casing body 20 has an inner cover 21 at one end and an outer cover 22 at the other end. The other outer cover 23 is disposed so as to cover the inner cover 21 and is attached to the casing body 20.

Inside the casing 20, a rotor 24 for compressing the refrigerant gas and a motor 26 for rotating the rotor 24 are incorporated. The outer cover 22 has a rotor 2
A suction port 27 for taking in refrigerant gas from the outside is provided for the inner cover 21 with the rotors 24, 25.
A passage 28 for introducing the refrigerant gas compressed by the inside into the external cover 23, and a discharge port 29 for introducing the refrigerant gas to the outside are provided in the external cover 23, respectively. External inlet 27 and
The compressed refrigerant gas is discharged from the discharge port 29 through the passage 28 to the outside through the passage 26.

The rotor 24 is a male-side rotor. As shown in FIG. 2, the female-side rotor 25 and the slide valve 3 are provided.
Along with 0, it is accommodated in a hole or groove formed in the casing body 20, and a compression chamber 31 is formed between them. Returning to FIG. 1, the male rotor 24 is the shaft 3
2 is held by a radial bearing 33 in the casing 20, a radial bearing 34 and a thrust bearing 35 in the inner cover 21. In the figure, the radial bearing 3
4 and the thrust bearing 35 are different from the internal cover 21 in cross-sectional position, so only one side is shown. The shaft of the female rotor 25 is also held by bearings in the casing body 20 and the inner cover 21 similarly to the male rotor. Of these shafts, only the shaft 32 of the male rotor is connected to the rotating shaft of the motor 26,
By rotating the male rotor 24 by the motor 26, the female rotor 25 is driven to rotate. The slide valve 30 is slid by a hydraulic cylinder. The hydraulic cylinder is incorporated in the inner cover 21, and the piston 36 is connected to the slide valve 30 by the rod 37, moves the piston 36, and moves the slide valve 30 to discharge the refrigerant gas to the outside. Is opened and closed so that the load on the compressor body can be changed.

Further, a port for cooling the refrigerant gas and discharging oil for lubricating the rotors 24 and 25 is provided on the casing body 20 with a suction side of the rotors 24 and 25 or a rotor. Oil from an external oil tank is provided between the oil passages 24 and 25 and passes through these oil passages.
It is found inside the shing body 20 and is compressed by the rotors 24 and 25 together with the refrigerant gas.
An oil separator 3 is provided inside the outer cover 23.
9, the casing body 20 has a rotor 24,
An oil reservoir 40 is provided at a lower portion of the outer cover 25, and an oil passage 41 connected to the oil reservoir is provided at a lower portion of the outer cover 23 at a lower portion of the flange. The oil passage 41 is separated from the refrigerant gas by an oil separator 39. The collected oil passes through the oil passage 41 into the oil sump 40 and is collected from the oil sump 40 to the oil tank.

The condenser 11 has a suction side connected to a discharge port 29 in the outer cover 23 of the compressor body 10 and a discharge side connected to the expansion valve 12. The evaporator 13 has an inlet connected to the expansion valve and an outlet connected to a suction port 27 in the outer cover 22 of the compressor body 10.

In this screw compressor, the compressor body 1
When 0 operates, the low-temperature, low-pressure refrigerant gas heat-exchanged in the evaporator 13 is sucked into the inside of the compressor main body 10 from the suction port 27 to cool the motor 26, and then to the rotors 24, 25. Inhaled. The high-temperature, high-pressure refrigerant gas compressed by these rotors is sent through the passage 26 to the inside of the external cover 22, and is discharged from the discharge port 29 through the oil separator 39. The high-temperature and high-pressure refrigerant gas from which the oil has been separated is cooled and condensed into a medium-temperature and high-pressure refrigerant liquid in the condenser 11, and this refrigerant liquid is expanded in the expansion valve 12, and then heated in the evaporator 13. It is exchanged and becomes low-temperature and low-pressure refrigerant gas. The refrigerant gas leaving the evaporator 13 is again sucked through the suction port 2 of the compressor body 10, cools the motor 26, and then is sucked into the rotors 24 and 25. Is performed.

On the other hand, when the compressor main body 10 operates, the oil from the oil tank in which the oil is disposed outside is discharged from the casing main body 2.
The oil is supplied to the suction side of the rotors 24, 25 or between the rotors through an oil passage at zero. The hot oil is mixed with the refrigerant gas, passes through the passage 26, is passed through the oil separator 39, is separated from the refrigerant gas by the demister in the oil separator, and is discharged from the discharge port 29. The separated oil is
Along with the oil supplied to the bearings holding the shafts of the motors 24 and 25, the oil is collected in an oil reservoir 40 at the bottom of the casing 20, and then collected in an oil tank.

However, in the screw compressor according to the present invention, the rotor tooth surface is provided with a plurality of fine recesses for retaining oil.

The recess is indicated by reference numeral 41 in FIG. 3 and is provided on the entire tooth surface of the female rotor 25.

Each of the depressions 42 has a hemispherical shape, and one size is irregularly or
As shown in FIG. 4, a plurality of sizes are irregularly provided on the rotor. The ratio between the diameter of the depression and the depth is, for example, 0.001 to 1 so that the ratio between the diameter of one depression and the pitch of the depression adjacent to the depression is 1 to 6.

The rotor 24 having such recesses 42,
25, the rotor 2
Even if the engagement between the rotor 24 and the rotor 25 is not smooth due to errors in the tooth profile, lead, indexing, etc. of 4 and 25, the surface of each rotor is Since the formed oil film can be maintained and the contact between metals can be avoided, the generation of noise can be reduced over a long period of time. explain in detail.

In the oil-cooled screw compressor, the oil sucked from the rotor suction side or between the rotor and the rotor at the same time as the operation is supplied to the outer peripheral surface of the rotor and the hole into which the rotor is inserted. Because there is a slight gap between the inner circumference of
Entering into this gap, as the rotor rotates,
The rotor spreads on the wall surface of the hole in which the rotor is inserted, and an oil film is formed between the tip of the rotor tooth and the hole. However, the oil that has entered the contact surface or meshing surface of each rotor tooth surface, as the rotor rotates,
Since the oil film is hardly formed on the contact surface or meshing surface of each rotor tooth surface due to the centrifugal force, the metal surfaces come into direct contact with each other and generate noise.

In the screw compressor according to the present invention, oil for cooling the refrigerant gas is supplied to the rotor 24 and the rotor.
When supplied between the suction side of the rotor 25 or the rotors 24, 25, the supplied oil is supplied to these rotors 24, 25.
As the rotors 24 and 25 rotate, the rotors 24 and 25 enter the meshing surfaces of the rotors, and are held in the respective recesses 42 on the tooth surfaces.
3 and the oil film 43 is maintained. For this reason, the generation of sound based on the direct contact of the rotors 24 and 25 between the tooth surfaces can be suppressed, and the noise can be reduced. The oil film 43 formed in the region on the discharge side and the region on the suction side in the tooth surfaces of the rotors 24 and 25 prevents leakage of the refrigerant gas or reduces leakage of the refrigerant gas, thereby improving the compression performance. You can also do.

The recess 42 is processed by, for example, a shot blast method. Since the depression 42 is provided on the tooth surface of the female rotor 25 as described above, the shot is projected on a valley portion forming the tooth surface, and the projected shot is formed on a mountain portion forming the tooth surface. Processing can be performed easily and in a short time.

Further, the recess 42 may be provided only on the advance surface of the tooth surface of the female rotor 25, which is indicated by reference numeral 44 in FIG.

The recesses 42 arranged in this manner are not only made to have a hemispherical shape by processing by a shot blast method, but also rolled by a female side rotor and a roller having a complementary shape. The shape, size, and arrangement of the depressions can be arbitrarily selected by performing processing by forming, for example, the depressions 42 are not only formed in a hemispherical shape but also in a semi-elliptical shape as shown in FIGS. As shown in FIGS. 7 and 8, the conical shape is used, and any one of a cylindrical shape is used as shown in FIGS. 9 and 10, and a staggered shape is used as shown in FIG. 11 and a lattice shape is used as shown in FIG. , Or, as shown in FIG. 13, regularly arranging a plurality of cavities, or arranging cavities of a plurality of shapes and sizes regularly or irregularly. Door can be. Also at this time, each of the depressions 42 has a ratio of diameter to depth of 0.001 to 1,
The recesses are arranged on the rotor such that the ratio of the diameter of one recess to the pitch of the adjacent recess is 1-6.

In this case, the recess 42 is formed on the female side row.
By providing it not only in the advance surface of the tooth flank but also in the area on the suction side or the area on the discharge side,
An oil film is formed on the suction side and / or the discharge side of the rotor to reduce the leakage of gas compressed by the rotor from the suction side and / or the discharge side of the rotor. Therefore, the compression performance of the compressor can be improved. In this case, the depressions in the areas on the suction side and the discharge side have a hemispherical shape and are irregularly arranged by the shot blast method, but each of the depressions has a ratio of diameter to depth of 0. .001 to 1, the ratio of the diameter of a given cavity to the pitch of the neighboring cavity is 1 to 6
It is made to become.

[0030]

As described above, in the oil-cooled screw compressor of the present invention, the recess provided in the rotor tooth surface holds oil such as waste oil in the oil injection and suction side bearings, Since the oil film on the rotor engagement surface is maintained, noise from the rotor engagement surface can be reduced for a long period of time.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of an oil-cooled screw compressor according to the present invention.

FIG. 2 is an enlarged sectional view around a rotor taken along line AA of FIG. 1;

FIG. 3 is an enlarged sectional view of a rotor surface.

FIG. 4 is an explanatory view showing an arrangement state of depressions.

FIG. 5 is an enlarged plan view showing another form of the depression.

6 is a sectional view of the depression shown in FIG.

FIG. 7 is an enlarged plan view showing still another form of the depression.

FIG. 8 is an enlarged sectional view of the depression shown in FIG. 7;

FIG. 9 is an enlarged plan view showing still another form of the depression.

FIG. 10 is an enlarged sectional view of the depression shown in FIG. 9;

FIG. 11 is an explanatory view showing another arrangement state of the depressions.

FIG. 12 is an explanatory view showing still another arrangement state of the depressions.

FIG. 13 is an explanatory view showing still another arrangement state of the depressions.

[Explanation of symbols]

25: Male rotor, 26: Female rotor, 41: Recess, 42: Oil film.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-3-100390 (JP, A) JP-A-54-67210 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F04C 18/16

Claims (1)

(57) [Claims] 1. A lubrication type screw compressor in which oil is supplied to a suction side or a rotor to cool compression heat and lubricate contact surfaces of rotors, a tooth serving as a female advance surface of the rotor. Hemisphere on surface
An oil-cooled screw compressor, wherein a plurality of shaped depressions are formed, and the oil is retained by these depressions.