TW201627577A - Screw compressor - Google Patents

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 compressors

The present invention relates to a screw compressor, and more particularly to a screw compressor having a sliding valve.

The prior screw compressor has a casing body and a spiral rotor that is rotatably housed in a cylinder chamber formed in the casing body. Further, in the screw compressor, some have a slide valve which controls a part of the refrigerant introduced into the compression chamber to bypass the low pressure space during the compression stroke to control the operation capacity (for example, refer to the patent document) 1). This sliding valve is disposed on the outer circumference of the spiral rotor and is movable in the axial direction of the spiral rotor.

As described above, the slide valve is provided in the outer circumference of the spiral rotor so as to be movable in the axial direction of the spiral rotor, between the casing body side of the slide valve (hereinafter referred to as the back side) and the sliding valve side of the casing body. A gap is created.

Further, the surface of the spiral rotor side of the sliding valve (hereinafter, referred to as an inner peripheral surface) is disposed so as to be located radially outward of the inner peripheral surface of the cylinder chamber in order to prevent mutual contact between the sliding valve and the spiral rotor. . Therefore, the gap between the inner circumferential surface of the slide valve and the outer circumferential surface of the spiral rotor is larger than the gap between the inner circumferential surface of the cylinder and the outer circumferential surface of the spiral rotor.

As described above, in the screw compressor, a gap necessary for the structure is provided on the back side and the inner peripheral surface side of the slide valve. Through these gaps, no The method avoids the refrigerant from the discharge pressure (high pressure) side, and does not leak to the suction pressure (low pressure) side, and the leakage causes the performance to be degraded.

In the technique of suppressing leakage of the refrigerant from the inner peripheral surface of the sliding valve, a covering member that fills a gap with the outer peripheral surface of the spiral rotor is provided on the inner peripheral surface of the sliding valve (see, for example, Patent Document 2).

[First technical literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2004-316586

Patent Document 2: Japanese Patent No. 4103709

As described above, in the above-described Patent Document 2, the covering member is provided on the inner circumferential surface of the sliding valve to reduce the gap with the outer peripheral surface of the spiral rotor, or to eliminate the gap to suppress leakage of the refrigerant from the inner peripheral surface side of the sliding valve. . However, it does not inhibit the leakage of the refrigerant from the gap in the back side of the sliding valve.

The casing body is formed with a partition wall separating the discharge pressure (high pressure) side and the suction pressure (low pressure) side (hereinafter referred to as a high and low pressure partition wall), and the inner peripheral side of the high and low pressure partition walls facing the back side of the slide valve . Further, between the back surface of the slide valve and the inner peripheral surface of the high-low pressure partition wall, a gap is provided in order to avoid contact with each other, and since this gap, a self-discharge pressure (high pressure) due to the high-low pressure partition wall is taken as a boundary The refrigerant leaks due to the pressure difference between the suction pressure (low pressure). In particular, the pressure difference of the high-pressure refrigerant such as R410A is likely to be large, and the performance degradation caused by leakage of the refrigerant from the back side of the sliding valve becomes remarkable.

The present invention has been developed in view of the above problems, and its object is to Provided is a screw compressor that suppresses leakage of a refrigerant from a gap between a back surface of a sliding valve and an inner peripheral surface of a high-low pressure partition wall.

The screw compressor of the present invention comprises: a casing body; a spiral rotor configured to rotate within the casing body; a sliding valve movably disposed between the casing body and the spiral rotor; and a high and low pressure partition wall formed and slid The back side of the valve faces each other to separate the casing body into a discharge pressure space and a suction pressure space, and an injection mechanism that supplies oil to a gap between the high and low pressure partition walls and the back side of the slide valve to seal the gap.

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

1‧‧‧ screw compressor

2‧‧‧Compression Department

3‧‧‧Motor

3a‧‧‧stator

3b‧‧‧Motor rotor

4‧‧‧ oil separator

5‧‧‧Condenser

6‧‧‧Expansion valve

7‧‧‧Evaporator

8‧‧‧Shell body

9‧‧‧Spiral rotor

10‧‧‧ screw

11‧‧‧Compression room

11a‧‧‧ screw groove

12‧‧‧Spit room

13‧‧‧Exporting

14‧‧‧Sliding valve

14a‧‧‧ valve body

14b‧‧‧Guidance

14c‧‧‧Connecting Department

14d‧‧‧Exhaust end

14e‧‧‧ inner circumference

14f‧‧‧back side

14g‧‧‧ oil hole

14h‧‧‧Spiral rotor supply port

14i‧‧‧Spiral rotor oil supply port

14j‧‧‧ oil hole

14k‧‧‧Slide valve rear part oil supply port

14l‧‧‧Sliding valve rear oil supply port

14m‧‧‧ oil trap

15‧‧‧ rod body

15a‧‧‧connection hole

16‧‧‧ drive

17‧‧‧High and low pressure dividing wall

17a‧‧‧ inner circumference

17b‧‧‧ Oil hole

17c‧‧‧Slide valve back port

18‧‧‧ oil groove

18a‧‧‧ oil groove

20‧‧‧Injection mechanism

80‧‧‧ shell body

90‧‧‧ spiral rotor

140‧‧‧Sliding valve

140a‧‧‧Back

170‧‧‧High and low pressure dividing wall

170a‧‧‧ inner circumference

S‧‧‧ sealing surface

Fig. 1 is a schematic block diagram showing a refrigeration system including a screw compressor according to a first embodiment of the present invention.

Fig. 2 is a schematic configuration diagram of a screw compressor according to a first embodiment of the present invention.

Fig. 3 is an explanatory view of the operation of the prior screw compressor which is a comparison object of the first embodiment.

Fig. 4 is a view showing a refrigerant leakage path viewed from the back side of the prior screw compressor as a comparison object of the first embodiment.

Fig. 5 is an explanatory view of the operation of the screw compressor according to the first embodiment of the present invention.

Fig. 6 is a perspective view showing an oil path viewed from the back side of the slide valve of the screw compressor according to the first embodiment of the present invention.

Figure 7 is a view showing the sliding valve of the screw compressor according to Embodiment 1 of the present invention. A three-dimensional view of the face.

Fig. 8 is a plan view showing the slide valve of the screw compressor according to the first embodiment of the present invention as viewed from the back side.

Figure 9 is a view in which the slide valve of Fig. 6 is reversed up and down to be viewed from the direction of the arrow X (the direction of the oil trap 14m can be seen).

Figure 10 is a cross-sectional view taken along line A-A of Figure 9.

Figure 11 is a cross-sectional view taken along line B-B of Figure 9.

Fig. 12 is a schematic view showing an important part of a screw compressor according to a second embodiment of the present invention.

Fig. 13 is a perspective view of the slide valve of the screw compressor according to the second embodiment of the present invention as viewed from the back side.

Figure 14 is a perspective view of a slide valve of a screw compressor according to a third embodiment of the present invention.

Fig. 15 is an explanatory view showing the positional relationship between the high and low pressure partition walls and the spiral groove of the stop position of the corresponding sliding valve of the screw compressor according to the third embodiment of the present invention.

Figure 16 is a perspective view of a slide valve of a screw compressor according to a fourth embodiment of the present invention.

Fig. 17 is a view showing the structure of a slide valve of a screw compressor according to a fifth embodiment of the present invention.

Embodiment 1

Fig. 1 is a schematic block diagram showing a refrigeration system including a screw compressor according to a first embodiment of the present invention. As shown in Fig. 1, the refrigeration system includes a screw compressor 1, a condenser 5, an expansion valve 6, an evaporator 7, and the like. Also, the screw compressor 1 includes: The compression unit 2; the motor 3 is connected in series to the compression unit 2, drives the compression unit 2; and the oil separator 4. In the screw compressor 1, the refrigerant discharged from the compression unit 2 is mixed with refrigerating machine oil (hereinafter referred to as oil), so that the refrigerant separator 4 separates the refrigerant and the oil. The separated oil is returned to the compression unit 2 by the pressure difference. In the first drawing, although the oil separator 4 is housed in the form of the screw compressor 1, the oil separator 4 may be additionally placed outside the screw compressor 1.

Fig. 2 is a schematic configuration diagram of a screw compressor according to a first embodiment of the present invention.

As shown in the schematic configuration of Fig. 2, the screw compressor includes a case body 8 in a cylindrical shape, a spiral rotor 9 housed in the case body 8, and a motor 3 that rotationally drives the spiral rotor 9. The motor 3 is composed of a stator 3a and a motor rotor 3b. The stator 3a is internally fixed to the case body 8. The motor rotor 3b is disposed inside the stator 3a. The spiral rotor 9 and the motor rotor 3b are arranged to be fixed to the screw 10 on the same axis.

Further, the spiral rotor 9 is formed with a plurality of spiral grooves (spiral grooves) 11a formed on the outer peripheral surface thereof, and is coupled to the motor rotor 3b fixed to the screw 10 to be rotationally driven. Further, the space in the spiral groove 11a is surrounded by the inner cylinder surface of the casing body 8 and a pair of gate rotors (not shown) to form the compression chamber 11. The pair of shutter rotors are engaged with the spiral groove 11a to engage. Further, the inside of the casing body 8 is partitioned between the discharge pressure side and the suction pressure side by the high and low pressure partition walls 17. The high and low pressure partition walls 17 are formed on the case body 8 so as to face the case body 8 side of the slide valve 14 described later. Further, on the discharge pressure side of the casing body 8, a discharge port 13 is formed in one of the openings in the discharge chamber 12.

Further, a slide valve 14 is provided in the case body 8. Sliding valve 14 It is coupled to the rod body 15 of the drive unit 16 and is movable in the axial direction of the spiral rotor 9. The slide valve 14 forms a part of the discharge port 13 and changes the position of the discharge opening to change the internal volume ratio by changing the position at which the discharge of the high-pressure gas after the compression chamber 11 is compressed (end compression).

Here, the internal volume ratio is the ratio of the volume of the compression chamber 11 at the time of ending the suction (starting compression) to the volume of the compression chamber 11 immediately before the discharge. Further, although the slide valve 14 may have two or more, the illustration is omitted. In the slide valve 14, the side of the casing body 8 is referred to as "back side", and the side of the spiral rotor 9 is referred to as "inner peripheral surface side".

Hereinafter, a prior screw compressor which is a comparison target of the first embodiment will be described.

Fig. 3 is an explanatory view of the operation of the prior screw compressor which is a comparison object of the first embodiment. In addition, Fig. 4 is a view showing a refrigerant leakage path viewed from the back side of the prior screw compressor as a comparison object of the first embodiment.

Previously, as described above, the slide valve 140 provided in the case body 80 is regarded as being movable in the axial direction of the spiral rotor 90, so that the back surface 140a of the slide valve 140 and a part of the case body 80 are used. There is a gap between the inner peripheral faces 170a of the high and low pressure partition walls 170. Here, the high-low pressure partition wall 170 is located at a position separating the discharge pressure (high pressure) side and the suction pressure (low pressure) side. Therefore, as indicated by an arrow a in FIG. 3, the refrigerant leaks from the gap, and the performance deteriorates. Question.

On the other hand, in the first embodiment, the following configuration is adopted.

Fig. 5 is an explanatory view of the operation of the screw compressor according to the first embodiment of the present invention. Further, Fig. 6 is a sliding view of the screw compressor of the first embodiment of the present invention. A perspective view of the oil path from the back side of the valve.

As shown in FIGS. 5 and 6 , the slide valve 14 of the first embodiment has injection oil to a gap formed between the back surface side 14 f of the slide valve 14 and the inner peripheral surface 17 a of the high and low pressure partition wall 17 . The injection mechanism 20 of the sealing surface S.

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 the first embodiment of the present invention as viewed from the inner surface side. Fig. 8 is a plan view showing the slide valve of the screw compressor according to the first embodiment of the present invention as viewed from the back side. Figure 9 is a view in which the slide valve of Fig. 6 is reversed up and down to be viewed from the direction of the arrow X (the direction of the oil trap 14m can be seen). Figure 10 is a cross-sectional view taken along line A-A of Figure 9. Figure 11 is a cross-sectional view taken along line B-B of Figure 9. In Figs. 10 and 11, arrows indicate oil paths.

Here, first, the basic structure of the slide valve 14 will be described, and thereafter, the injection mechanism 20 will be described. As shown in these figures, the slide valve 14 has a valve body 14a, a guide portion 14b, and a coupling portion 14c that connects these. A gap communicating with the discharge port 13 is formed between the valve body 14a and the guide portion 14b to form a portion of the discharge port 13. Further, in the valve 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 of discharging the compressed refrigerant. That is, the moving slide valve 14 is moved in the axial direction of the spiral rotor 9, and the discharge port end portion 14d is also moved in the axial direction of the spiral rotor 9, whereby the internal volume ratio is changed. Further, the guide portion 14b is provided with a connection hole 15a. As shown in Fig. 2, the rod 15 is coupled to the connection hole 15a.

As shown in Fig. 11, the slide valve 14 of the first embodiment is formed with oil that ejects high pressure to the oil supply hole 14g of the spiral rotor 9. Oil hole 14g The spiral rotor portion 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 is a spiral rotor portion oil supply port 14h which is an opening on the oil outflow side, and is located on the inner peripheral side 14e of the slide valve 14. . Regardless of the shape and number of holes of the oil supply hole 14g.

Further, in the slide valve 14 of the first embodiment, as shown in Fig. 5, Fig. 8, Fig. 9, and Fig. 10, the injection oil is formed between the high and low pressure partition walls 17 and the back side 14f of the slide valve 14. The oil supply hole 14j of the gap (sealing surface S). The oil supply hole 14j is a slide valve rear surface oil supply port 14l which is an opening of the oil inlet side of the oil supply hole 14j, and is located on the back side 14f of the slide valve 14. Further, the slide valve rear surface oil supply port 14k, which is an opening for the oil outflow side of the oil hole 14j, is located in the back side 14f of the slide valve 14 and faces the high and low pressure partition wall 17 as shown in Fig. 5. That is, it is located within the range of the sealing surface S. Regardless of the shape and number of holes of the oil supply hole 14j. Further, the oil supply hole 14j constitutes the first oil supply hole of the present invention.

Further, an oil trap 14m having a recess is formed on the back side 14f of the slide valve 14, and as shown in Fig. 9, the spiral rotor portion oil supply port 14i and the slide valve rear portion oil supply port 14l are located here. Oiler 14m.

Hereinafter, the flow of oil will be described.

In the screw compressor 1 of the first embodiment, the inner peripheral side 14e and the back side 14f of the slide valve 14 and the portion facing the same are provided from the viewpoint of suppressing leakage of the refrigerant from the spiral rotor 9 and preventing the melting. Between, spray high pressure oil.

Here, first, the injection of the inner peripheral side 14e of the slide valve 14 will be described. First, as shown in Fig. 1, the high-pressure oil in the oil separator 4 is supplied to the slide valve through a flow path (not shown) in the casing main body 8 by a pressure difference. 14 oil sump 14m. As a result, the oil supplied to the oil trap 14m flows into the oil supply hole 14g from the spiral rotor portion oil supply port 14i provided in the oil trap 14m by the pressure difference, and passes through the oil supply hole 14g from the spiral rotor portion. At the oil supply port 14h, high pressure oil is injected to the spiral rotor 9.

Next, the ejection of the back side 14f of the slide valve 14 will be described. In the first embodiment, the high-pressure oil is injected from the back side 14f to the sealing surface S as a feature. First, the oil in the aforementioned oil trap 14m to which the oil separator 4 is distributed is used. The high-pressure oil in the oil trap 14m flows into the oil supply hole 14j from the oil supply port 14l of the sliding valve rear surface provided in the oil trap 14m by the pressure difference, and passes through the oil supply hole 14g, and the oil is supplied from the back of the sliding valve. The portion of the oil supply port 14k is sprayed to the sealing surface S. Further, the oil supply hole 14g provided in the slide valve 14 constitutes the injection mechanism 20 of the present invention.

Further, in the first embodiment, the spiral rotor portion oil supply port 14i and the slide valve rear surface portion oil supply port 14l are located in the same oil trap 14m. However, the configuration is not necessarily required, and the configuration may be different. The oil trap is inside 14m. Further, the object of the first embodiment is of course to reduce the leakage of the refrigerant on the back side of the slide valve 14, and the oil supply hole 14j can be applied to the slide valve 14 having no oil supply hole 14g. Further, the high and low pressure partition walls 17 may be made thicker so that the oil supply holes 14j are disposed in the high and low pressure partition walls 17 even after the slide valve 14 is moved.

As described above, according to the first embodiment, since the injection mechanism 20 that injects the oil to the sealing surface S to be sealed is provided, the refrigerant can be prevented from leaking from the discharge pressure (high pressure) side to the suction pressure (low pressure) side. As a result, the efficiency of the screw compressor 1 can be improved, and energy saving can be expected.

The injection mechanism 20 has an oil supply hole 14j penetrating the slide valve 14, The oil that has flowed into the oil supply port 14l of the sliding valve rear surface of the self-priming oil hole 14j is supplied to the sealing surface S from the oil supply port 14k of the sliding valve back surface. It can be said that only the hole is opened in the slide valve 14, so that it can be configured inexpensively.

Embodiment 2

In the second embodiment, in comparison with the first embodiment, only the portion where the oil is supplied to the oil supply hole of the sealing surface S is different.

Fig. 12 is a schematic view showing an important part of a screw compressor according to a second embodiment of the present invention. Fig. 13 is a perspective view of the slide valve of the screw compressor according to the second embodiment of the present invention as viewed from the back side. Further, in the second embodiment, the difference from the first embodiment will be described, and the configuration that is not described in the second embodiment is the same as that of the first embodiment.

In the second embodiment, the oil supply hole 14j provided in the slide valve 14 is disposed in the first embodiment, and the oil supply hole 17b is provided in the high-low pressure partition wall 17 constituting a part of the casing body 8. Further, the slide valve back surface oil supply port 17c which is the opening of the oil supply port 17b on the oil outflow side is provided on the inner peripheral surface 17a of the high and low pressure partition wall 17, so that the high pressure oil flowing into the oil supply hole 17b is self-sliding from the back of the slide valve The portion of the oil supply port 17c is sprayed to the sealing surface S.

The position of the opening to the oil inflow side of the oil hole 17b is not particularly limited, and may be provided at a position where the oil in the screw compressor 1 is acceptable. Further, regardless of the shape and number of holes of the oil supply hole 17b. Further, the oil supply hole 17b constitutes the second oil supply hole of the present invention.

As described above, according to the second embodiment, the self-sealing surface S is suppressed from the oil supply port 17c to the sealing surface S of the sliding valve rear surface provided on the inner peripheral surface 17a of the high and low pressure partition wall 17 by the high pressure oil. Spit pressure (high On the pressure side, leakage of refrigerant to the suction pressure (low pressure) side improves the efficiency of the screw compressor 1.

Embodiment 3

In the third embodiment, the point at which the oil groove is provided only on the back side 14f of the slide valve 14 is different from that in the first embodiment.

Figure 14 is a perspective view of a slide valve of a screw compressor according to a third embodiment of the present invention. Further, in the third embodiment, the difference from the first embodiment is intended to be described, and the configuration that is not described in the first embodiment is the same as that of the first embodiment.

In the third embodiment, in the first embodiment, the oil injected into the sealing surface S is efficiently entered into the sealing surface S, and the circumferential side 14f of the valve body 14a of the slide valve 14 is formed in the circumference. An oil groove 18 extending in the direction. The processing position of this oil groove 18 is within the range of the sealing surface S. Moreover, the oil groove 18 constitutes the first oil groove of the present invention. Regardless of the cross-sectional shape and number of the aforementioned oil grooves 18.

Fig. 15 is an explanatory view showing the positional relationship between the high and low pressure partition walls and the spiral groove of the stop position of the corresponding sliding valve of the screw compressor according to the third embodiment of the present invention. As shown in Fig. 15, by the sliding position of the slide valve 14, the position of the oil groove 18 sometimes spans between the spiral grooves 11a. The pressures in the respective spiral grooves 11a are different from each other, so that when the oil grooves 18 straddle the spiral grooves 11a, the spiral groove 11a on the high pressure side and the spiral groove 11a on the low pressure side are borrowed. The oil groove 18 is connected, and it is possible 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 leakage passage of the refrigerant, the oil groove 18 is not limited to the entire circumferential direction of the back side 14f of the slide valve 14, and may be configured. In the back side 14f, the portion where the groove processing is not applied remains.

In this way, by providing the oil groove 18, the oil injected from the oil supply port 14k of the sliding valve back portion to the sealing surface S enters the sealing surface S efficiently.

The oil groove 18 is provided not only on the back side 14f of the slide valve 14, but also on the inner peripheral surface 17a of the high-low pressure partition wall 17 on which the sealing surface S is formed, or both. Further, when the oil groove is provided on the inner circumferential surface 17a of the high and low pressure partition wall 17, it extends in the circumferential direction like the oil groove 18. As a result, the oil groove provided on the inner peripheral surface 17a of the high and 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, from the back side 14f of the slide valve 14, the oil injected to the sealing surface S passes through the oil groove 18, and it is easy to enter the entire circumference of the back surface of the slide valve. Therefore, in the third embodiment, the oil groove 18 is provided in comparison with the case where the configuration of the first embodiment (the configuration of the spool valve rear surface oil supply port 14k is provided), and the refrigerant self-sealing surface S can be suppressed. Leakage pressure (high pressure) side, leakage to the suction pressure (low pressure) side. As a result, the efficiency of the screw compressor 1 can be further improved.

Embodiment 4

The fourth embodiment corresponds to the configuration in which the second embodiment and the third embodiment are combined. In other words, the oil groove 18 is provided on the slide valve 14 of the screw compressor 1 of the second embodiment which is characterized in that the injection oil is applied to the sealing surface S from the high and low pressure partition wall 17 side. Further, the shape and formation position of the oil groove 18 are the same as those in the third embodiment.

Figure 16 is a perspective view of a slide valve of a screw compressor according to a fourth embodiment of the present invention. Furthermore, in the fourth embodiment, it is intended to describe the embodiment and the embodiment. The difference between 2 and 2 is the same as that of the second embodiment.

As indicated by the hollow arrow in Fig. 16, from the side of the high and low pressure partition wall 17, the oil sprayed to the sealing surface S flows along the oil groove 18 as indicated by a solid arrow, and enters the sealing surface S efficiently.

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, from the side of the high and low pressure partition wall 17, the oil sprayed to the sealing surface S passes through the oil groove 18, and it is easy to enter the entire circumference of the back surface of the sliding valve. Therefore, in the fourth embodiment, the refrigerant can be suppressed by the action of the oil groove 18 as compared with the case where the configuration of the second embodiment (the configuration of the injection oil to the sealing surface S from the high and low pressure partition wall 17 side) is separately performed. Leakage on the suction pressure (low pressure) side from the discharge pressure (high pressure) side in the self-sealing surface S. As a result, the efficiency of the screw compressor 1 can be further improved.

Embodiment 5

In the fifth embodiment, the oil sump 14m and the oil groove 18 are characterized.

Fig. 17 is a view showing the structure of a slide valve of a screw compressor according to a fifth embodiment of the present invention.

The sliding valve 14 of the first embodiment shown in the above-mentioned ninth embodiment is configured such that the oil in the oil trap 14m is supplied to the oil hole 14j and passes through the valve body 14a, and the injected oil is sealed from the rear surface of the sliding valve to the oil supply port 14k. Face S.

On the other hand, in the configuration of the fifth embodiment, the oil flows along the back side (outer peripheral surface) of the slide valve 14 and is ejected to the sealing surface S. Specifically, the oil supply hole 14j of the first embodiment is cut, and the oil groove 18a is connected to the oil accumulator 14m so that the high-pressure oil in the oil trap 14m passes through the oil groove 18a. Sprayed to the sealing surface S. The oil groove 18a of the fifth embodiment differs from the oil groove 18 of the third embodiment in that it only communicates with the oil accumulator 14m, and the other is the same as the oil groove 18 of the third embodiment. Further, the oil groove 18a constitutes the second oil groove of the present invention.

As described above, according to the fifth embodiment, the oil supply hole 14j penetrating the slide valve 14 can be provided without passing through the first to fourth embodiments, and the high-pressure oil of the oil trap 14m can be caused to enter the sealing surface S. Therefore, the leakage of the refrigerant can be suppressed by a simpler configuration, and the efficiency of the screw compressor 1 can be improved.

Further, Embodiments 1 to 5 can be combined as appropriate. In the first embodiment and the second embodiment, for example, the oil may be sprayed onto the sealing surface S from both the back side 14f of the slide valve 14 and the inner peripheral surface 17a of the high and low pressure partition wall 17.

Further, the first to fifth embodiments 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, a single-stage screw compressor having one compression unit 2 is exemplified, but a multi-stage screw compressor having two or more compression units 2 may be used. Further, the present invention can be applied not only to a screw compressor of a certain speed specification but also to a screw compressor driven by an inverter.

Further, in the first to fifth embodiments, the slide valve 14 is a slide valve whose internal volume ratio is variable. However, the slide valve of the present invention is not limited to the case where the internal volume ratio is variable. For example, a slide valve for capacity control that allows a part of the refrigerant gas to bypass the suction side (low pressure) may be used, or may be fixed to the case body 8 and the slide valve that is not movable.

1‧‧‧ screw compressor

2‧‧‧Compression Department

3‧‧‧Motor

4‧‧‧ oil separator

5‧‧‧Condenser

6‧‧‧Expansion valve

7‧‧‧Evaporator

Claims (9)

A screw compressor comprising: a casing body; a spiral rotor configured to rotate within the casing body; a sliding valve movably disposed between the casing body and the spiral rotor; and a partition wall formed to be slid The back side of the valve faces to separate the casing body into a discharge pressure space and a suction pressure space, and an injection mechanism that supplies oil to a gap between the inner peripheral surface of the partition wall and the back side of the slide valve to seal the gap . The screw compressor according to claim 1, wherein the injection mechanism includes one or more first oil supply holes formed through the sliding valve, and an opening on one end side of the first oil supply hole is formed The partition walls face each other and supply oil from the opening to the gap. The screw compressor according to claim 2, wherein the injection mechanism further includes a first oil groove, and the first oil groove is disposed on a back side of the slide valve and is disposed to face the partition wall There is an oil that is supplied to the aforementioned gap. The screw compressor according to claim 3, wherein the first oil groove is provided on the back side of the slide valve in the circumferential direction. The screw compressor according to any one of claims 2 to 4, wherein the back side of the slide valve has an oil trap formed by a recess, and the other end side of the first oil supply hole is tied to The aforementioned oil trap is open. The screw compressor according to claim 1, wherein the injection mechanism includes an oil trap, and a back side of the slide valve And a second oil groove provided on the back side of the sliding valve facing the partition wall; the oil trap and the second oil groove are connected to each other to make the oil trap The oil is supplied from the second oil groove to the gap. The screw compressor according to any one of claims 1 to 4, wherein the injection mechanism has one or more second oil supply holes formed in the partition wall, the first The opening of the one end side of the oil supply hole is opened on the inner peripheral surface of the partition wall so that oil is supplied to the gap. The screw compressor according to any one of claims 1 to 4, wherein the injection mechanism further has a third oil groove, and the third oil groove is provided in the partition wall. The inner peripheral surface of the oil flows through the oil supplied to the gap. The screw compressor according to claim 8, wherein the third oil groove is circumferentially provided on an inner circumferential surface of the partition wall.