WO2016121021A1

WO2016121021A1 - Screw compressor

Info

Publication number: WO2016121021A1
Application number: PCT/JP2015/052275
Authority: WO
Inventors: 克也前田; 雅章上川; 伊藤　健
Original assignee: 三菱電機株式会社
Priority date: 2015-01-28
Filing date: 2015-01-28
Publication date: 2016-08-04
Also published as: EP3252310B1; TW201627577A; EP3252310A4; TWI579464B; CN207333184U; EP3252310A1

Abstract

A screw compressor is provided with: a casing body (8); a screw rotor (9) disposed so as to rotate within the casing body (8); a slide valve (14) provided in a movable manner between the casing body (8) and the screw rotor (9); a high-low pressure partition wall (17) formed so as to face the rear surface side (14f) of the slide valve (14) and dividing the inside of the casing body (8) into a discharge pressure space and a suction pressure space; and an injection mechanism (20) for supplying oil to the gap between the high-low pressure partition wall (17) and the rear surface side of the slide valve (14), thereby sealing the gap.

Description

Screw compressor

The present invention relates to a screw compressor, and particularly to a screw compressor provided with a slide valve.

A conventional screw compressor includes a casing main body and a screw rotor rotatably accommodated in a cylinder chamber formed in the casing main body. Some screw compressors further include a slide valve that controls the operating capacity by bypassing a part of the refrigerant introduced into the compression chamber to the low pressure space in the middle of the compression stroke (for example, Patent Documents). 1). This slide valve is disposed on the outer periphery of the screw rotor and is movable in the axial direction of the screw rotor.

As described above, the slide valve is provided on the outer periphery of the screw rotor so as to be movable in the axial direction of the screw rotor. The slide valve has a casing body side (hereinafter referred to as a back side) and a slide valve side of the casing body. There is a gap between them.

In general, the surface on the screw rotor side of the slide valve (hereinafter referred to as the inner peripheral surface) is radially outward from the inner peripheral surface of the cylinder chamber in order to avoid mutual contact between the slide valve and the screw rotor. It is arranged to be located. Therefore, the clearance between the inner peripheral surface of the slide valve and the outer peripheral surface of the screw rotor is larger than the clearance between the inner peripheral surface of the cylinder and the outer peripheral surface of the screw rotor.

As described above, in the screw compressor, a gap necessary for the structure is provided on each of the back surface side and the inner peripheral surface side of the slide valve. Through these gaps, it is inevitable that the refrigerant leaks from the discharge pressure (high pressure) side to the suction pressure (low pressure) side, and there is a problem that this leakage causes a decrease in performance.

As a technique for suppressing refrigerant leakage from the inner peripheral surface of the slide valve, there is one in which a covering member is provided on the inner peripheral surface of the slide valve so as to fill a gap between the outer peripheral surface of the screw rotor (for example, see Patent Document 2). .

JP 2004-316586 A Japanese Patent No. 4103709

In Patent Document 2, as described above, the covering member is provided on the inner peripheral surface of the slide valve to reduce the gap between the outer peripheral surface of the screw rotor or eliminate the gap, so that It suppresses refrigerant leakage. However, it did not suppress refrigerant leakage from the gap on the back side of the slide valve.

The casing body is formed with a partition wall (hereinafter referred to as a high and low pressure partition wall) that separates the discharge pressure (high pressure) side and the suction pressure (low pressure) side, and the inner peripheral side of the high and low pressure partition wall is on the back side of the slide valve. Facing. A gap is provided between the back surface of the slide valve and the inner peripheral surface of the high and low pressure partition wall so as to avoid mutual contact. From this clearance, the discharge pressure (high pressure) with the high and low pressure partition wall as a boundary is provided. The refrigerant leaks due to the pressure difference from the suction pressure to the suction pressure (low pressure). In particular, the high pressure refrigerant such as R410A has a problem that the differential pressure tends to increase, and the performance deterioration due to refrigerant leakage from the back side of the slide valve becomes significant.

The present invention has been made to solve the above-described problems, and suppresses refrigerant leakage from the gap between the back surface of the slide valve and the inner peripheral surface of the high and low pressure partition wall, and provides a highly efficient screw compressor. The purpose is to provide.

A screw compressor according to the present invention includes a casing main body, a screw rotor arranged to rotate within the casing main body, a slide valve provided movably between the casing main body and the screw rotor, Oil is supplied to the gap between the partition wall, which is formed facing the back side and separates the inside of the casing body into a discharge pressure space and a suction pressure space, and between the inner peripheral surface of the partition wall and the back side of the slide valve. And an injection mechanism for sealing.

According to the present invention, refrigerant leakage from the gap between the back surface of the slide valve and the inner peripheral surface of the high and low pressure partition wall can be suppressed, and the performance of the screw compressor can be improved.

It is a figure which shows schematic structure of the freezing apparatus provided with the screw compressor which concerns on this Embodiment 1 of this invention. It is a schematic block diagram of the screw compressor which concerns on this Embodiment 1 of this invention. FIG. 3 is an operation explanatory diagram according to a conventional screw compressor shown as a comparison target of the first embodiment. It is the figure which showed the refrigerant | coolant leak path | route at the time of seeing the conventional slide valve shown as a comparison object of Embodiment 1 from the back side. It is operation | movement explanatory drawing of the screw compressor which concerns on Embodiment 1 of this invention. It is the perspective view which showed the oil path | route at the time of seeing the slide valve of the screw compressor which concerns on Embodiment 1 of this invention from the back side. It is the perspective view which looked at the slide valve of the screw compressor which concerns on Embodiment 1 of this invention from the inner surface side. It is the top view which looked at the slide valve of the screw compressor concerning this Embodiment 1 of the present invention from the back side. It is the figure which turned the slide valve of FIG. 6 upside down, and was seen from the arrow X direction (direction which can see the oil sump 14m). FIG. 10 is a sectional view taken along line AA in FIG. 9. FIG. 10 is a sectional view taken along line BB in FIG. 9. It is the schematic which showed the principal part of the screw compressor which concerns on Embodiment 2 of this invention. It is the perspective view which looked at the slide valve of the screw compressor which concerns on Embodiment 2 of this invention from the back part side. It is a perspective view of the slide valve of the screw compressor which concerns on Embodiment 3 of this invention. It is explanatory drawing of the positional relationship of the high-low pressure partition according to the stop position of the slide valve of the screw compressor which concerns on Embodiment 3 of this invention, and a screw groove. It is a perspective view of the slide valve of the screw compressor which concerns on Embodiment 4 of this invention. It is a figure which shows the structure of the slide valve of the screw compressor which concerns on Embodiment 5 of this invention.

Embodiment 1 FIG.
FIG. 1 is a diagram showing a schematic configuration of a refrigeration apparatus including a screw compressor according to Embodiment 1 of the present invention. As shown in FIG. 1, the refrigeration apparatus includes a screw compressor 1, a condenser 5, an expansion valve 6, an evaporator 7, and the like. The screw compressor 1 includes a compression unit 2, a motor 3 connected in series to the compression unit 2, and driving the compression unit 2, and an oil separator 4. In the screw compressor 1, since the refrigerant discharged from the compression unit 2 contains refrigeration oil (hereinafter referred to as oil), the oil separator 4 separates the refrigerant into oil. The oil after separation is returned to the compression section 2 using differential pressure. In FIG. 1, the specification in which the oil separator 4 is built in the screw compressor 1 is shown. However, the oil separator 4 may be separately provided outside the screw compressor 1.

FIG. 2 is a schematic configuration diagram of the screw compressor according to the first embodiment of the present invention.
As shown schematically in FIG. 2, the screw compressor includes a cylindrical casing body 8, a screw rotor 9 accommodated in the casing body 8, and a motor 3 that rotationally drives the screw rotor 9. I have. The motor 3 includes a stator 3a that is inscribed and fixed to the casing body 8, and a motor rotor 3b that is disposed inside the stator 3a. The screw rotor 9 and the motor rotor 3 b are arranged on the same axis line, and both are fixed to the screw shaft 10.

The screw rotor 9 has a plurality of spiral grooves (screw grooves) 11a formed on the outer peripheral surface thereof, and is driven to rotate by being connected to a motor rotor 3b fixed to the screw shaft 10. Further, the space in the screw groove 11a is surrounded by the inner cylindrical surface of the casing body 8 and a pair of gate rotors (not shown) engaged with and engaged with the screw groove 11a to form the compression chamber 11. Further, the inside of the casing body 8 is separated by a high and low pressure partition wall 17 into a discharge pressure side and a suction pressure side. The high / low pressure partition wall 17 is formed on the casing body 8 so as to face the casing body 8 side of the slide valve 14 described later. A pair of discharge ports 13 that open to the discharge chamber 12 are formed on the discharge pressure side of the casing body 8.

Furthermore, a slide valve 14 is provided in the casing body 8. The slide valve 14 is connected to the rod 15 of the driving device 16 and is movable in the axial direction of the screw rotor 9. The slide valve 14 forms a part of the discharge port 13, and changes the discharge opening timing by changing the discharge start (compression completion) position of the high-pressure gas compressed in the compression chamber 11, thereby changing the internal volume ratio. It is a mechanism to change.

Here, the internal volume ratio is a ratio between the volume of the compression chamber 11 at the time of completion of suction (start of compression) and the volume of the compression chamber 11 just before the discharge. Although two or more slide valves 14 may be provided, the illustration is omitted. In the following, in the slide valve 14, the casing body 8 side is referred to as “rear side” and the screw rotor 9 side is referred to as “inner peripheral surface side”.

Hereinafter, a conventional screw compressor will be described as a comparison object of the first embodiment.

FIG. 3 is an operation explanatory view according to a conventional screw compressor shown as a comparison target of the first embodiment. FIG. 4 is a diagram showing a refrigerant leakage path when a conventional slide valve shown as a comparison target of the first embodiment is viewed from the back side.
Conventionally, as described above, the slide valve 140 provided in the casing main body 80 is movable in the axial direction of the screw rotor 90, so that the back surface 140 a of the slide valve 140 and a part of the casing main body 80 are high. There is a gap between the inner peripheral surface 170a of the low-pressure partition wall 170a. Here, since the high / low pressure partition 170 is located at a position separating the discharge pressure (high pressure) side and the suction pressure (low pressure) side, refrigerant leakage occurs from this gap as shown by an arrow a in FIG. It was a challenge.

On the other hand, the first embodiment has the following configuration.

FIG. 5 is an operation explanatory diagram of the screw compressor according to Embodiment 1 of the present invention. FIG. 6 is a perspective view showing an oil path when the slide valve of the screw compressor according to Embodiment 1 of the present invention is viewed from the back side.
As shown in FIGS. 5 and 6, the slide valve 14 of the first embodiment has a seal surface S formed by a gap between the back side 14 f of the slide valve 14 and the inner peripheral surface 17 a of the high-low pressure partition wall 17. An injection mechanism 20 for injecting oil is provided.

Hereinafter, the injection mechanism 20 will be described in detail.

FIG. 7 is a perspective view of the slide valve of the screw compressor according to Embodiment 1 of the present invention as viewed from the inner surface side. FIG. 8 is a plan view of the slide valve of the screw compressor according to the first embodiment of the present invention as viewed from the back side. FIG. 9 is a view of the slide valve of FIG. 6 turned upside down as seen from the direction of the arrow X (the direction in which the oil sump 14m can be seen). 10 is a cross-sectional view taken along the line AA in FIG. 11 is a cross-sectional view taken along the line BB in FIG. In FIGS. 10 and 11, the arrows indicate the oil paths.

Here, first, the basic structure of the slide valve 14 will be described, and then the injection mechanism 20 will be described. As shown in these drawings, the slide valve 14 includes a valve main body 14a, a guide portion 14b, and a connecting portion 14c for connecting them. A gap communicating with the discharge port 13 is formed between the valve main body 14a and the guide portion 14b, and a part of the discharge port 13 is formed. Further, in the valve main body 14a, the inner peripheral side 14e of the discharge port end portion 14d of the discharge port 13 forms a part of the discharge port 13 and determines the timing for discharging the compressed refrigerant. That is, the internal volume ratio is changed by moving the slide valve 14 in the axial direction of the screw rotor 9 and simultaneously moving the discharge port end portion 14 d in the axial direction of the screw rotor 9. Further, a connecting hole 15a is provided in the guide portion 14b, and the rod 15 is coupled to the connecting hole 15a as shown in FIG.

In the slide valve 14 of the first embodiment, an oil supply hole 14g for injecting high-pressure oil into the screw rotor 9 is formed so as to penetrate therethrough as shown in FIG. In the oil supply hole 14g, the screw rotor part oil supply port 14i which is an opening on the oil inflow side is located on the back side 14f of the slide valve 14, and the screw rotor part oil supply port 14h which is an opening on the oil outflow side is inside the slide valve 14. It is located on the circumferential side 14e. The hole shape and number of the oil supply holes 14g are not limited.

Further, the slide valve 14 according to the first embodiment includes a gap (seal surface S) between the high / low pressure partition wall 17 and the back side 14f of the slide valve 14 as shown in FIGS. ) Is formed with an oil supply hole 14j for injecting oil. The oil supply hole 14j has a slide valve back surface oil supply port 14l that is an opening on the oil inflow side of the oil supply hole 14j and is located on the back side 14f of the slide valve 14. Then, as shown in FIG. 5, the slide valve back surface oil supply port 14k, which is the opening on the oil outflow side of the oil supply hole 14j, is opposed to the high / low pressure partition wall 17 on the back surface 14f of the slide valve 14, that is, the seal surface S. Located within range. The hole shape and the number of the oil supply holes 14j are not limited. The oil supply hole 14j constitutes the first oil supply hole of the present invention.

An oil sump 14m composed of a depression is formed on the back side 14f of the slide valve 14. As shown in FIG. 9, the screw rotor part oil supply port 14i and the slide valve back part are formed in the oil sump 14m. An oil supply port 14l is located.

Hereinafter, the flow of oil will be described.
In the screw compressor 1 according to the first embodiment, each of the inner peripheral side 14e and the rear side 14f of the slide valve 14 from the viewpoint of suppressing refrigerant leakage from the screw rotor 9 and preventing seizure, and the portions facing the respective sides. High pressure oil is injected between the two.

Here, first, the injection of the inner peripheral side 14e of the slide valve 14 will be described. First, as shown in FIG. 1, high-pressure oil in the oil separator 4 is supplied to an oil reservoir 14m provided in the slide valve 14 through a flow path (not shown) in the casing body 8 by differential pressure. Thereby, the oil supplied to the oil reservoir 14m flows into the oil supply hole 14g from the screw rotor oil supply port 14i provided in the oil reservoir 14m by the differential pressure, passes through the oil supply hole 14g, and is supplied to the screw rotor oil supply. High pressure oil is injected into the screw rotor 9 from the opening 14h.

Next, the injection on the back side 14f of the slide valve 14 will be described. The first embodiment is characterized in that high-pressure oil is injected from the back side 14 f to the seal surface S. First, the oil in the oil reservoir 14m distributed from the oil separator 4 is used. The high pressure oil in the oil reservoir 14m flows into the oil supply hole 14j from the slide valve rear surface oil supply port 14l provided in the oil reservoir 14m by the differential pressure, passes through the oil supply hole 14g, and passes through the oil supply hole 14g. Oil is injected into the sealing surface S from 14k. The oil supply hole 14g provided in the slide valve 14 constitutes the injection mechanism 20 of the present invention.

In the first embodiment, the screw rotor oil supply port 14i and the slide valve back surface oil supply port 14l are positioned in the same oil sump 14m. It is good also as a structure located in the oil sump 14m. The first embodiment is intended only to reduce refrigerant leakage on the back side of the slide valve 14, and the oil supply hole 14j can be applied to the slide valve 14 that does not include the oil supply hole 14g. Further, the high / low pressure partition wall 17 may be thick so that the oil supply hole 14j is disposed in the high / low pressure partition wall 17 even when the slide valve 14 moves.

As described above, according to the first embodiment, since the injection mechanism 20 that seals the seal surface S by injecting oil is provided, refrigerant leakage from the discharge pressure (high pressure) side to the suction pressure (low pressure) side is prevented. Can be suppressed. As a result, the efficiency of the screw compressor 1 can be improved, which can contribute to energy saving.

The injection mechanism 20 has an oil supply hole 14j that passes through the slide valve 14, and supplies oil that has flowed in from the slide valve back surface oil supply port 14l of the oil supply hole 14j to the seal surface S from the slide valve back surface oil supply port 14k. In other words, since it has a configuration in which a hole is formed in the slide valve 14, it can be configured at low cost.

Embodiment 2. FIG.
The second embodiment is different from the first embodiment only in the portion where the oil supply hole for supplying oil to the seal surface S is provided.

FIG. 12 is a schematic view showing a main part of a screw compressor according to Embodiment 2 of the present invention. FIG. 13: is the perspective view which looked at the slide valve of the screw compressor which concerns on Embodiment 2 of this invention from the back part side. In the second embodiment, differences from the first embodiment will be described, and configurations not described in the second embodiment are the same as those in the first embodiment.
In the second embodiment, the oil supply hole 14j provided in the slide valve 14 in the first embodiment is abolished, and the oil supply hole 17b is provided in the high / low pressure partition wall 17 constituting a part of the casing body 8. . Then, a slide valve back surface oil supply port 17c, which is an opening on the oil outflow side of the oil supply hole 17b, is provided on the inner peripheral surface 17a of the high and low pressure partition wall 17, and the high pressure oil flowing into the oil supply hole 17b is supplied to the slide valve back surface oil supply port 17c. To the sealing surface S.

The position of the opening on the oil inflow side of the oil supply hole 17b is not particularly limited as long as it is provided at a position where the oil in the screw compressor 1 can be received. Further, the hole shape and the number of the oil supply holes 17b are not limited. The oil supply hole 17b constitutes the second oil supply hole of the present invention.

As described above, according to the second embodiment, high-pressure oil is injected into the seal surface S from the slide valve back surface oil supply port 17 c provided on the inner peripheral surface 17 a of the high-low pressure partition wall 17, thereby discharging on the seal surface S. Refrigerant leakage from the pressure (high pressure) side to the suction pressure (low pressure) side can be suppressed, and the efficiency of the screw compressor 1 can be improved.

Embodiment 3 FIG.
The third embodiment is different from the first embodiment only in that an oil groove is provided on the back side 14f of the slide valve 14.

FIG. 14 is a perspective view of a slide valve of the screw compressor according to Embodiment 3 of the present invention. In the third embodiment, differences from the first embodiment will be described, and configurations not described in the first embodiment are the same as those in the first embodiment.
In the third embodiment, the oil groove 18 extending in the circumferential direction on the back surface side 14f of the valve body 14a of the slide valve 14 in order to efficiently spread the oil injected to the seal surface S in the first embodiment to the seal surface S. Is formed. The processing position of the oil groove 18 is within the range of the seal surface S. The oil groove 18 constitutes the first oil groove of the present invention. The cross-sectional shape and the number of the oil grooves 18 are not limited.

FIG. 15 is an explanatory diagram of the positional relationship between the high and low pressure partition walls and the screw grooves according to the stop position of the slide valve of the screw compressor according to Embodiment 3 of the present invention. As shown in FIG. 15, depending on the slide position of the slide valve 14, the position of the oil groove 18 may straddle between the screw grooves 11a. Since the pressure in each screw groove 11a is different from each other, when the oil groove 18 straddles between the screw grooves 11a in this way, the oil groove 18 causes the screw groove 11a on the high pressure side and the screw groove 11a on the low pressure side to be separated. There is a possibility that the refrigerant leaks from the high pressure side to the low pressure side. Therefore, in order to prevent the oil groove 18 from becoming a refrigerant leakage passage in this way, the oil groove 18 is not limited to the configuration provided in the entire circumferential direction of the back side 14f of the slide valve 14, and the groove processing is performed on the back side 14f. You may leave a part that does not.

Thus, by providing the oil groove 18, the oil injected from the slide valve back surface oil supply port 14 k toward the seal surface S efficiently spreads over the seal surface S.

The oil groove 18 may be provided not only on the back side 14f of the slide valve 14 but also on the inner peripheral surface 17a forming the seal surface S of the high / low pressure partition wall 17, or both. In the case where an oil groove is provided on the inner peripheral surface 17 a of the high / low pressure partition wall 17, the oil groove 18 is formed so as to extend in the circumferential direction as with the oil groove 18. Thus, the oil groove provided on the inner peripheral surface 17a of the high / low pressure partition wall 17 constitutes the third oil groove of the present invention.

As described above, according to the third embodiment, the same effects as those of the first embodiment can be obtained, and the following effects can be obtained. That is, the oil injected from the back surface side 14 f of the slide valve 14 to the seal surface S easily reaches the entire periphery of the slide valve back surface through the oil groove 18. For this reason, in the third embodiment, the oil groove 18 is further provided on the seal surface S as compared with the case where the configuration of the first embodiment (the configuration in which the slide valve rear surface oil supply port 14k is provided) is further implemented. Refrigerant leakage from the discharge pressure (high pressure) side to the suction pressure (low pressure) side can be suppressed. As a result, the efficiency of the screw compressor 1 can be further improved.

Embodiment 4 FIG.
The fourth embodiment corresponds to a combination of the second embodiment and the third embodiment. That is, the oil groove 18 is provided in the slide valve 14 of the screw compressor 1 according to the second embodiment, in which oil is injected from the high / low pressure partition wall 17 into the seal surface S. Note that the shape, formation position, and the like of the oil groove 18 are the same as those in the third embodiment.

FIG. 16 is a perspective view of a slide valve of a screw compressor according to Embodiment 4 of the present invention. In the fourth embodiment, differences from the second embodiment will be described, and configurations not described in the second embodiment are the same as those in the second embodiment.
As indicated by the white arrows in FIG. 16, the oil injected from the high / low pressure partition wall 17 side to the seal surface S flows along the oil grooves 18 as indicated by the solid line arrows, and efficiently spreads to the seal surface S.

As described above, according to the fourth embodiment, the same effects as those of the second embodiment can be obtained, and the following effects can be obtained. That is, the oil injected into the seal surface S from the high / low pressure partition wall 17 side easily reaches the entire periphery of the slide valve back surface through the oil groove 18. For this reason, compared with the case where the configuration of the second embodiment (the configuration in which oil is injected into the seal surface S from the high / low pressure partition wall 17 side) is performed alone, the discharge pressure (high pressure) on the seal surface S is further increased by the action of the oil groove 18. ) Side refrigerant leakage from the suction pressure (low pressure) side can be suppressed. As a result, the efficiency of the screw compressor 1 can be further improved.

Embodiment 5 FIG.
The fifth embodiment is characterized in that the oil reservoir 14m and the oil groove 18 are communicated with each other.

FIG. 17 is a view showing the structure of the slide valve of the screw compressor according to Embodiment 5 of the present invention.
The slide valve 14 according to the first embodiment shown in FIG. 9 passes the oil in the oil reservoir 14m through the valve body 14a through the oil supply hole 14j, and supplies the oil from the slide valve rear surface oil supply port 14k to the seal surface S. The configuration was to inject.

On the other hand, the fifth embodiment is configured such that oil flows along the back side (outer peripheral surface) of the slide valve 14 and is injected into the seal surface S. Specifically, the oil supply hole 14j of the first embodiment is deleted, the oil groove 18a is provided so as to communicate with the oil reservoir 14m, and the high-pressure oil in the oil reservoir 14m is applied to the seal surface S through the oil groove 18a. It is configured to inject. The oil groove 18a of the fifth embodiment is the same as the oil groove 18 of the third embodiment except that the oil groove 18a is different from the oil groove 18 of the third embodiment in that it communicates with the oil reservoir 14m. The oil groove 18a constitutes the second oil groove of the present invention.

As described above, according to the fifth embodiment, the high pressure oil in the oil sump 14m is removed from the seal surface S without providing the oil supply hole 14j penetrating the slide valve 14 as in the first to fourth embodiments. Can be spread over. Therefore, refrigerant leakage can be suppressed with a simpler configuration, and the efficiency of the screw compressor 1 can be improved.

Note that Embodiments 1 to 5 can be appropriately combined. For example, oil may be injected into the sealing surface S from both the back surface side 14f of the slide valve 14 and the inner peripheral surface 17a of the high / low pressure partition wall 17 by combining the first embodiment and the second embodiment.

Further, Embodiments 1 to 5 are applicable to all screw compressors having a mechanism having a gap between the back side 14f of the slide valve 14 and the inner peripheral surface 17a of the high / low pressure partition wall 17. For example, in the above description, the single-stage screw compressor including one compression unit 2 is illustrated, but a multi-stage compressor including two or more compression units 2 may be used. Further, the present invention is useful not only for a constant speed specification screw compressor but also for an inverter driven screw compressor.

In the first to fifth embodiments, the slide valve 14 is a slide valve having a variable internal volume ratio. However, the slide valve to which the present invention is applied is not limited to a valve having a variable internal volume ratio. For example, a slide valve for capacity control that can bypass part of the refrigerant gas to the suction side (low pressure) may be used, or a slide valve that is fixed to the casing body 8 and is not movable may be used.

1 Screw compressor, 2 compression section, 3 motor, 3a stator, 3b motor rotor, 4 oil separator, 5 condenser, 6 expansion valve, 7 evaporator, 8 casing body, 9 screw rotor, 10 screw shaft, 11 compression Chamber, 11a Screw groove, 12 Discharge chamber, 13 Discharge port, 14 Slide valve, 14a Valve body, 14b Guide portion, 14c Connection portion, 14d Discharge port end, 14e Inner peripheral side, 14f Back side, 14g Oil supply hole, 14h Screw rotor part oil supply port, 14i Screw rotor part oil supply port, 14j Oil supply hole, 14k Slide valve rear part oil supply port, 14l Slide valve rear part oil supply port, 14m Oil reservoir, 15 Rod, 15a connection hole, 16 Drive unit, 17 High / low pressure partition, 17a Inner peripheral surface, 17b Oil supply hole, 17c Slide valve rear surface oil supply port, 18 oil groove, 18a oil groove, 20 injection mechanism, 80 casing body, 90 screw rotor, 140 slide valve, 140a rear surface, 170 high / low pressure partition wall, 170a inner peripheral surface, S seal surface.

Claims

A casing body;
A screw rotor arranged to rotate within the casing body;
A slide valve movably provided between the casing body and the screw rotor;
A partition that is formed to face the back side of the slide valve and separates the inside of the casing body into a discharge pressure space and a suction pressure space;
The screw compressor provided with the injection mechanism which supplies oil to the clearance gap between the internal peripheral surface of the said partition, and the back side of the said slide valve, and seals the said clearance gap.
The injection mechanism has one or more first oil supply holes formed through the slide valve, and an opening on one end side of the first oil supply hole is formed to face the partition, The screw compressor according to claim 1, wherein oil is supplied to the gap.
The screw compressor according to claim 2, wherein the injection mechanism further includes a first oil groove provided on the back side of the slide valve so as to face the partition wall and through which oil supplied to the gap flows.
The screw compressor according to claim 3, wherein the first oil groove is provided in a circumferential direction on a back side of the slide valve.
The back side of the slide valve has an oil sump constituted by a recess, and the other end side of the first oil supply hole opens into the oil sump. Screw compressor.
The injection mechanism includes an oil sump formed of a depression on the back side of the slide valve, and a second oil groove provided on the back side of the slide valve so as to face the partition wall, and the oil sump 2. The screw compressor according to claim 1, wherein the screw compressor is provided in communication with the second oil groove and supplies oil in the oil reservoir from the second oil groove to the gap.
The injection mechanism has one or more second oil supply holes formed in the partition wall, and an opening on one end side of the second oil supply hole opens on an inner peripheral surface of the partition wall to supply oil to the gap. The screw compressor according to any one of claims 1 to 6, wherein the screw compressor has the configuration as described above.
The screw compression according to any one of claims 1 to 7, wherein the injection mechanism further includes a third oil groove that is provided on the inner peripheral surface of the partition wall and through which oil supplied to the gap flows. Machine.
The screw compressor according to claim 8, wherein the third oil groove is provided on an inner peripheral surface of the partition wall in a circumferential direction.