JP2017044123A - Screw compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a screw compressor having a pressure resisting function to suppress deformation of oil seals in one set of oil seals and improved in a service life of a seal device and compressor efficiency.SOLUTION: A screw compressor includes a screw rotor having a rotor tooth portion, a suction-side shaft portion and a discharge-side shaft portion, a suction-side bearing, a discharge-side bearing, and a casing. A seal device is disposed to seal the discharge-side shaft portion between a discharge end face side of the rotor tooth portion of the screw rotor and the discharge-side bearing. The seal device includes an oil seal having a lip portion of the V-shaped cross section, and an external lip deformation prevention member for holding the outer face shape of the oil seal. The oil seal has a lip supporting portion for supporting the lip portion, a seal back face portion connected to the lip supporting portion, and a seal outer peripheral portion connected to the seal back face portion, and the external lip deformation prevention member is disposed from a seal back face portion of the oil seal to the lip portion.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a screw compressor, and is particularly suitable as a screw compressor used in an air conditioner or a refrigerator, or a screw compressor that compresses air.

  As a conventional screw compressor, there exists a thing described in Unexamined-Japanese-Patent No. 9-324860 (patent document 1), for example. In this patent document 1, a seal device having a pressure resistance function for holding the pressure generated on the rotor side is provided at the shaft portion between the gear that uses oil and the rotor that generates pressure, like a supercharger. It has been. In addition, the sealing device has a long life and has pressure resistance, and two sets of oil seals are arranged in parallel in the axial direction to form a sealed space between both oil seals. The pressure resistance and sealing performance are ensured.

JP-A-9-324860

  In the thing of the said patent document 1, although the sealing device which has a pressure | voltage resistant function holding the pressure which generate | occur | produces on the rotor side is provided, in order to set it as the sealing device which has a pressure | voltage resistant function, 2 sets of oil seals are used. For this reason, the sealing device becomes longer in the axial direction of the rotor, and the space for installing the sealing device is required twice as much as that in the case where it is constituted by a set of oil seals. Therefore, there is a problem that it cannot be adopted for a case where a sufficient installation space for the sealing device cannot be secured.

  Moreover, in the thing of patent document 1, although it can employ | adopt for the thing with comparatively low pressure like a supercharger (supercharger), when it uses for things with high pressure like a screw compressor, an oil seal will deform | transform. There is a problem that the contact friction with the shaft increases and the life and efficiency are lowered.

  An object of the present invention is to obtain a screw compressor having a pressure resistance function capable of suppressing deformation of an oil seal with a set of oil seals and capable of improving the life of a seal device and the compressor efficiency.

  To achieve the above object, the present invention provides a screw rotor having a rotor tooth portion, a suction side shaft portion and a discharge side shaft portion, a suction side bearing for supporting the suction side shaft portion of the screw rotor, and the discharge side. A screw compressor including a discharge-side bearing and a casing for housing these when supporting the shaft portion, wherein the discharge-side shaft between the discharge end surface side of the rotor tooth portion of the screw rotor and the discharge-side bearing A sealing device that seals the portion, and the sealing device is provided with an oil seal having a lip portion having a V-shaped cross section, and an outer surface shape of the oil seal provided on the outer surface (non-sealing side surface) of the oil seal The oil seal includes a lip support portion that supports the lip portion, a back surface portion of the seal that is connected to the lip support portion, Has a seal perimeter that is connected to the seal back portion, said outer lip deformation preventing member is characterized by being provided from said sealing rear portion of the oil seal to the lip.

  According to the present invention, an effect of obtaining a screw compressor having a pressure resistance function capable of suppressing the deformation of the oil seal with one set of oil seals and improving the life of the seal device and the compressor efficiency is obtained. It is done.

The horizontal sectional view which shows Example 1 of the screw compressor of this invention. FIG. 2 is an essential part cross-sectional view showing, in an enlarged manner, a portion of a sealing device for a discharge side shaft of the male rotor shown in FIG. The expanded longitudinal cross-sectional view of the oil seal with a spring used as an oil seal shown in FIG. FIG. 4 is an enlarged longitudinal sectional view of the oil seal showing a state where the spring is removed from the spring-loaded oil seal shown in FIG. 3. The longitudinal cross-sectional view which expands and shows the external lip deformation | transformation prevention member shown in FIG. The longitudinal cross-sectional view which expands and shows the internal lip deformation | transformation prevention member shown in FIG. FIG. 6 is an enlarged longitudinal sectional view showing another example of the external lip deformation preventing member shown in FIG. 5. The principal part sectional drawing which expands and shows the part of the sealing device in Example 2 of the screw compressor of this invention. The expanded longitudinal cross-sectional view of the oil seal without a spring used as an oil seal shown in FIG. The longitudinal cross-sectional view which expands and shows the internal lip deformation | transformation prevention member shown in FIG. FIG. 9 is an enlarged longitudinal sectional view showing another example of the sealing device shown in FIG. 8.

  Hereinafter, specific examples of the screw compressor of the present invention will be described with reference to the drawings. In each figure, the part which attached | subjected the same code | symbol has shown the part which is the same or it corresponds.

A screw compressor according to a first embodiment of the present invention will be described with reference to FIGS.
First, the overall configuration of the screw compressor according to the first embodiment will be described with reference to FIG. FIG. 1 is a horizontal sectional view of a screw compressor according to the first embodiment. The screw compressor according to the first embodiment is used in a refrigeration cycle apparatus such as a refrigerator or an air conditioner and compresses refrigerant flowing through the refrigeration cycle. And a hermetic screw compressor configured in a hermetic manner.

  The screw compressor 100 is housed in a casing 3 having a suction port 7 and a discharge port (not shown) in a state where a pair of male and female screw rotors (male rotor 1 and female rotor 2) are engaged. . The male rotor 1 and the female rotor 2 have rotor tooth portions 1a and 2a, suction side shaft portions 1b and 2b, and discharge side shaft portions 1c and 2c, respectively, and the suction side shaft portions 1b and 2b are respectively The casing 3 is supported by a male rotor suction side bearing 8 and a female rotor suction side bearing 9 provided in the main casing 3 a of the casing 3, and the discharge side shaft portions 1 c and 2 c are in the D casing (discharge casing) 3 b of the casing 3. Are supported by a male rotor discharge side bearing 10 and a female rotor discharge side bearing 11. A lip seal 12 seals the suction side shaft portion 1 b of the male rotor 1 between the male rotor suction side bearing 8 and the motor 4.

  The end portion of the suction-side shaft portion 1b of the male rotor 1 is directly connected to the motor rotor 4a of the motor 4 provided in the motor casing 3c so as to be directly connected.

  The refrigerant flowing through the refrigeration cycle is sucked into the motor casing 3c through the suction filter 6 provided at the end of the motor casing 3c, passes through the motor 4 and cools the motor 4, and enters the main casing 3a. It flows into the suction port 7 provided. The refrigerant flowing into the suction port 7 flows into the rotor groove (rotor tooth portion 1a) of the pair of male and female screw rotors, is compressed along with the rotation of the screw rotor, and is discharged from the discharge port.

  The compressed refrigerant gas discharged from the discharge port is mixed with lubricating oil. The refrigerant gas containing the lubricating oil flows into an oil separator (not shown) to separate the lubricating oil. Lubricating oil is supplied to the discharge-side bearings 10 and 11 from an oil supply hole 20 provided in the D casing 3b by a differential pressure from an oil tank below the oil separator. Note that the suction side bearings 8 and 9 are supplied with oil supply paths branched from the oil supply holes 20 formed in the D casing 3b in the casing 3b.

The male rotor discharge side shaft portion 1c and the female rotor discharge side shaft portion 2c are disposed in the shaft hole 5 provided in the discharge end surface portion (the portion of the D casing 3b on the rotor tooth portion 1a, 2a side) 33 of the D casing 3b. It penetrates through the gap.
In the conventional screw compressor, oil is supplied between the gap, that is, the gap between the shaft hole 5 in the discharge end face portion 33 and the male rotor discharge side shaft portion 1c and the female rotor discharge side shaft portion 2c. 10 and 11 are lubricated, and the refrigerant is prevented from leaking from the discharge end face side of the rotor tooth portions 1a and 2a to the bearing chamber 51 in which the discharge side bearings 10 and 11 are accommodated.

  However, the pressure of the refrigerant leaking from the discharge end face side of the rotor tooth portions 1a, 2a is the discharge pressure of the screw compressor, and the maximum is about 1 MPa of the discharge pressure. On the other hand, the oil pressure supplied from the oil separator to the discharge-side bearings 10 and 11 through the oil supply pipe and the oil supply path is lower than the discharge pressure by the pressure loss of the oil supply pipe and the oil supply path. About 0.4 MPa.

  Accordingly, even if oil is supplied to the shaft hole 5 in the discharge end surface portion 33, the differential pressure between the discharge end surface side (high pressure side) and the bearing chamber 51 side (low pressure side) of the rotor tooth portions 1a and 2a becomes large. In the conventional screw compressor, the leakage of the compressed refrigerant gas from the discharge end face side to the bearing chamber 51 side cannot be sufficiently suppressed. The refrigerant leaked from the discharge end face side to the bearing chamber 51 side flows into the bearing chamber 51 and then, along with the lubricating oil that lubricates the discharge side bearings 10 and 11, an oil supply passage formed in the casing 3. It passes through the suction port 7 and is collected. As described above, in the conventional screw compressor, the amount of leakage of the compressed refrigerant gas to the suction port 7 side is increased, which is a factor in reducing the performance of the screw compressor.

  Therefore, in the screw compressor 100 of the present embodiment, the discharge-side shaft portions 1c and 2c between the discharge end face side of the rotor tooth portions 1a and 2a of the screw rotor and the discharge-side bearings 10 and 11 are sealed. The sealing device 13 is provided so that the leakage of the compressed refrigerant gas from the discharge end surface side to the bearing chamber 51 side can be sufficiently suppressed. However, if an oil seal as described in Patent Document 1 described above is provided as the sealing device 13, the installation space increases, and the screw compressor becomes large. Further, since a large differential pressure acts on the seal device 13, the oil seal is deformed, and the contact friction with the shaft is increased, causing the life of the oil seal and the efficiency of the screw compressor to be reduced.

  In order to solve such a new problem, in this embodiment, the sealing device 13 is configured as shown in FIG. FIG. 2 is an enlarged cross-sectional view showing a main part of the seal device 13 of the discharge-side shaft portion 1c of the male rotor 1 shown in FIG. In addition, since the part of the sealing device 13 of the discharge side shaft portion 2c of the female rotor 2 has the same configuration, the description thereof is omitted.

  As shown in FIG. 2, the sealing device 13 is provided between the discharge end surface 33 a of the discharge end surface portion 33 in the D casing 3 b and the male rotor discharge side bearing 10. The sealing device 13 includes an oil seal 16 that performs sealing by contacting a bush 19 fitted to the outer peripheral surface of the male rotor discharge-side shaft portion 1c, and an outer surface of the oil seal 16 (the non-sealing side (low pressure in the oil seal) The outer lip deformation preventing member 15 provided on the bearing chamber side surface and retaining the outer surface shape of the oil seal, and the inner surface of the oil seal 16 (the surface on the sealing side (high pressure side) of the oil seal; An inner lip deformation preventing member 17 that is provided on the rotor tooth portion side surface and holds the inner shape of the oil seal. As the material of the outer lip deformation preventing member 15 and the inner lip deformation preventing member 17, it is preferable to use a material having high rigidity such as metal, composite resin, engineering plastic or the like.

The bush 19 is provided at a portion in contact with the oil seal 16 of the discharge side shaft portion 1 c and has a hardness and surface roughness suitable for sliding with the oil seal 16.
The oil seal 16 has a lip portion having a substantially V-shaped cross section, and the lip portion is brought into contact with the bush 19 of the male rotor discharge side shaft portion 1c for sealing. In the example shown in FIG. 2, the oil seal 16 is used in a state (see FIG. 4) excluding the spring of a spring-loaded oil seal (see FIG. 3) used by providing a spring on the outer peripheral side of the lip portion. ing.

  An oil supply groove 18 having a width of about 10 mm formed in the circumferential direction is machined on the inner peripheral surface of the outer lip deformation preventing member 15 and supplied from an oil supply hole 20 (see FIG. 1) provided in the D casing 5. The lubricating oil is supplied to the male rotor discharge-side bearing 10 through the gap between the external lip deformation preventing member 15 and the bush 19. Reference numeral 14 denotes a presser plate for pressing the external lip deformation preventing member 15.

  A detailed configuration of the oil seal 16 will be described with reference to FIGS. 3 and 4. 3 is an enlarged longitudinal sectional view of a spring-loaded oil seal used as the oil seal 16 shown in FIG. 2, and FIG. 4 is an enlarged longitudinal sectional view of the oil seal showing a state where the spring is removed from the spring-loaded oil seal shown in FIG. .

  FIG. 3 shows a general spring-loaded oil seal used as the oil seal 16. The oil seal is standardized by JIS (Japanese Industrial Standard) and is commercially available. In this embodiment, this commercially available spring-loaded oil seal is used, but it is not used as it is, but in a state where the spring is removed. As shown in FIG. 3, the spring-loaded oil seal has a V-shaped lip portion 22, a lip support portion 39 that supports the lip portion 22, and a seal back surface portion 38 that is connected to the lip support portion 39. And a seal outer peripheral portion 37 connected to the seal back surface portion 38.

21 is a spring provided on the outer peripheral side of the lip portion 22 (the inner surface 45 side of the lip portion 22), and improves the sealing performance by pressing the lip portion 22 against the bush 19 of the discharge side shaft portion 1c. is there.
In FIG. 3, 34 is a sealing side (high pressure side; rotor tooth side) of the oil seal, 35 is a non-sealing side (low pressure side; bearing chamber side), 40 is a lip front surface of the lip portion 22, and 41 is a lip portion. The lip rear surface 22, 42 is the lip tip of the lip 22, 43 is the inner surface of the seal outer periphery 37, 44 is the inner surface of the seal back surface 38, and 45 is the inner surface of the lip 22 as described above.

  4 shows a state in which the spring 21 is removed from the spring-loaded oil seal 16 shown in FIG. 3, and the spring-loaded oil seal 16 is in a state where the spring is removed as shown in FIG. Used for the device 13.

  The standard oil seal 16 is formed of a rubber-based elastic material, and the inner diameter of the lip tip portion 42 of the lip portion 22 in the oil seal 16 is outside the discharge-side shaft portion 1c to be inserted. It is configured to be slightly smaller than the diameter (outer diameter of the bush 19), and when inserted into the discharge side shaft 1c, which is a sliding portion, it generates a tightening force (tightening force) to prevent oil leakage. I have to.

  As shown in FIG. 3, the spring-loaded oil seal normally has a spring 21 set on the outer peripheral surface of the lip portion 22 to further prevent oil leakage by increasing the tightening force. However, in this embodiment, even if a minute leak occurs in the sealing device 13, priority is given to suppressing an increase in friction loss of the lip portion 22, and an oil seal is used in a state where the spring is removed. That is, the lip portion 22 of the oil seal 16 is configured to come into light contact with the discharge side shaft 1c (or the bush 19).

  That is, as described above, in the conventional screw compressor, sealing is performed by supplying oil between the shaft hole 5 in the discharge end surface portion 33 and the discharge side shaft portions 1c and 2c. The amount of high-pressure refrigerant leaked from Accordingly, even if the spring of the spring-loaded oil seal 16 is removed and used in the sealing device 13 of the present embodiment, the amount of refrigerant leakage from the sealing device 13 is greatly reduced as compared with the conventional screw compressor. it can.

  Next, the configuration of the external lip deformation preventing member 15 constituting the sealing device 13 shown in FIG. 2 will be described in detail with reference to FIG. FIG. 5 is an enlarged longitudinal sectional view of the external lip deformation preventing member 15 shown in FIG.

  As shown in FIG. 2, the external lip deformation preventing member 15 is provided on the outer surface (the non-sealing side (low pressure side) surface) of the oil seal 16 and maintains the outer surface shape of the oil seal. As shown in FIG. 5, the external lip deformation preventing member 15 includes a lip support for holding a seal back portion outer surface holding portion 31 for holding the outer surface 52 of the seal back portion 38 of the oil seal 16 and an outer surface 53 of the lip support portion 39. A lip rear surface holding portion 47 that holds the outer surface holding portion 46 and the lip rear surface 41 is provided. That is, the external lip deformation preventing member 15 in this embodiment is provided from the seal back surface portion 38 of the oil seal 16 to the lip portion 22.

  Further, the seal back portion outer surface holding portion 31 is adapted to the outer surface shape of the seal back portion 38 of the oil seal 16 shown in FIG. 4, the lip support portion outer surface holding portion 46 is adapted to the outer surface shape of the lip support portion 39, and The lip rear surface holding portion 47 matches the shape of the lip rear surface 41 of the lip portion 22. For this reason, when the external lip deformation preventing member 15 is installed in the sealing device 13, the holding portions 31, 46, 47 that come into contact with the oil seal 16 of the external lip deformation preventing member 15 are connected to the outer surface 52, the oil seal 16. 53 and the lip rear surface 41 are in close contact except for the vicinity of the lip tip 42. Reference numeral 18 denotes an oil supply groove formed in the circumferential direction on the inner peripheral surface of the outer lip deformation preventing member 15.

  Thus, according to the present embodiment, the external lip deformation preventing member 15 is provided from the seal back surface portion 38 to the lip portion 22 of the oil seal 16. Therefore, in the seal device 13 according to the present embodiment, the rotor tooth portion. Even if high pressure pressure by compressed gas acts on the oil seal 16 from the discharge end face side of 1a, 2a, the lip portion 22 can be prevented from being deformed to the non-sealing side (low pressure side).

  Next, the configuration of the internal lip deformation preventing member 17 constituting the sealing device 13 shown in FIG. 2 will be described in detail with reference to FIG. 6 is an enlarged longitudinal sectional view of the internal lip deformation preventing member 17 shown in FIG.

  As shown in FIG. 2, the internal lip deformation preventing member 17 is provided on the inner surface (the surface on the sealing side (high pressure side)) of the oil seal 16 to maintain the inner shape of the oil seal. As shown in FIG. 6, the inner lip deformation preventing member 17 includes a seal outer peripheral portion inner surface holding portion 48 that holds the inner surface 43 of the seal outer peripheral portion 37 of the oil seal 16, and a seal rear surface that holds the inner surface 44 of the seal back portion 38. And a lip portion inner surface holding portion 50 for holding the inner surface (outer peripheral surface) 45 of the lip portion 22.

  Further, the seal outer peripheral portion inner surface holding portion 48 matches the shape of the inner surface 43 of the seal outer peripheral portion 37 of the oil seal 16 shown in FIG. 4, and the seal back portion inner surface holding portion 49 is the shape of the inner surface 44 of the seal rear portion 38. Further, the lip portion inner surface holding portion 50 is matched with the shape of the inner surface 45 of the lip support portion 39. For this reason, when the internal lip deformation preventing member 17 is installed in the seal device 13, the holding portions 48, 49, and 50 that are in contact with the oil seal 16 of the internal lip deformation preventing member 17 are connected to the inner surface 43, the oil seal 16. 44 and 45.

  Therefore, even if high pressure pressure by compressed gas acts on the oil seal 16 from the discharge end face side of the rotor tooth portions 1a, 2a, the oil seal 16 can be prevented from being deformed inward (sealed side). As a result, since the deformation of the lip portion 22 having a V-shaped cross section can be suppressed, an increase in sliding friction loss with the discharge side shaft portions 1c, 2c (or the bush 19) can be suppressed, and the oil The seal 16 can also suppress the leakage of the refrigerant to the bearing chamber 51.

  That is, with the configuration of the present embodiment described above, it is possible to suppress the deformation of the oil seal by providing only one set of oil seals, and to improve the life of the seal device and the compressor efficiency. A screw compressor can be obtained.

  FIG. 7 is an enlarged longitudinal sectional view showing another example of the external lip deformation preventing member 15 shown in FIG. In the example shown in FIG. 7, an axial oil supply groove 26 connecting the oil supply groove 18 formed in the circumferential direction and the lip portion 22 side of the oil seal 16 on the inner peripheral surface of the external lip deformation preventing member 15. It is equipped with. A plurality of the oil supply grooves 26 are formed in the circumferential direction of the inner surface of the outer lip deformation preventing member 15.

  By configuring the external lip deformation preventing member 15 as shown in FIG. 7, the lubricating oil supplied to the oil supply groove 18 can be supplied to the lip portion 22 of the oil seal 16 via the oil supply groove 26. Therefore, the sliding friction loss of the oil seal 16 can be reduced, and the life of the oil seal 16 can be extended. Also, the efficiency of the screw compressor can be improved.

  Next, Embodiment 2 of the screw compressor of the present invention will be described with reference to FIGS. 8 to 11, the parts denoted by the same reference numerals as those in FIGS. 1 to 7 indicate the same or corresponding parts. The description of the same parts as those in the first embodiment is omitted, and different parts are mainly described. explain.

  In the second embodiment, an example in which a springless oil seal 24 without a spring is used as the oil seal constituting the sealing device 13 will be described.

  First, the configuration of the sealing device 13 according to the second embodiment will be described with reference to FIG. FIG. 8 is an enlarged cross-sectional view showing a main part of the sealing device according to the second embodiment of the screw compressor of the present invention. Also in this embodiment, the sealing device 13 provided on the discharge-side shaft portion 1c of the male rotor 1 will be described, and the sealing device 13 provided on the discharge-side shaft portion 2c of the female rotor 2 has the same configuration. The description is omitted.

  Also in the present embodiment, the sealing device 13 is provided between the discharge end surface 33a of the discharge end surface portion 33 and the male rotor discharge side bearing 10 in the D casing 3b, as described in FIG. . As shown in FIG. 8, the sealing device 13 includes an oil seal 24 that performs sealing by contacting the bush 19 fitted to the outer peripheral surface of the male rotor discharge-side shaft portion 1 c, and an outer surface (non-surface) of the oil seal 24. The outer lip deformation preventing member 15 provided on the sealing side surface and the inner lip deformation preventing member 23 provided on the inner surface (sealing side surface) of the oil seal 24 are provided.

In the present embodiment, the oil seal 24 uses a springless oil seal as it is.
The outer lip deformation preventing member 15 provided on the outer surface of the oil seal 24 has the same configuration as that of the first embodiment described with reference to FIG. 5, and the outer lip deformation preventing member 15 has a circular shape on its inner peripheral surface. An oil supply groove 18 formed in the circumferential direction is provided, and as shown in FIG. 1, the lubricating oil supplied from the oil supply hole 20 provided in the D casing 3b is efficiently supplied to the discharge side bearings 10 and 11. It is configured to be able to. The suction side bearings 8 and 9 are also configured so that the lubricating oil can be supplied from the oil supply passage branched from the oil supply hole 20 in the casing 3. Since the other structure regarding the said external lip deformation | transformation prevention member 15 is the same as that of what was demonstrated in Example 1, those description is abbreviate | omitted.

  The configuration of the springless oil seal 24 will be described with reference to FIG. FIG. 9 is an enlarged longitudinal sectional view of a springless oil seal used as the oil seal 24 shown in FIG. The springless oil seal 24 shown in FIG. 9 is also standardized according to JIS and is commercially available. In this embodiment, the commercially available springless oil seal 24 is used as it is. The cross-sectional shape of the springless oil seal 24 has a simpler structure than that of the spring-loaded oil seal 16 described above, but the lip portion 22 has a V-shaped cross-sectional shape in the vicinity of the lip tip portion 42. Like the spring-loaded oil seal 16 described above, it has a convex shape on the circumferential side, and is configured to come into light contact with the discharge-side shaft portions 1c, 2c (or bush 19), and has a narrow range of 1 mm or less. Slide on.

  The configuration of the inner lip deformation preventing member 23 provided on the inner surface (sealing side surface) of the oil seal 24 will be described with reference to FIG. FIG. 10 is an enlarged longitudinal sectional view of the internal lip deformation preventing member 23 shown in FIG.

  As shown in FIG. 8, the inner lip deformation preventing member 23 is provided on the inner surface (sealing side surface) of the oil seal 24 to maintain the inner shape of the oil seal 24. As shown in FIG. 10, the inner lip deformation preventing member 23 includes a seal outer peripheral portion inner surface holding portion 48 that holds the inner surface 43 of the seal outer peripheral portion 37 of the springless oil seal 24 (see FIG. 9), and a seal back portion 38. A seal back portion inner surface holding portion 49 that holds the inner surface 44 and a lip portion inner surface holding portion 50 that holds the inner surface (outer peripheral surface) 45 of the lip portion 22 are provided.

  Further, the seal outer peripheral portion inner surface holding portion 48 matches the shape of the inner surface 43 of the seal outer peripheral portion 37 of the springless oil seal 24 shown in FIG. Further, the lip portion inner surface holding portion 50 is matched with the shape of the inner surface 45 of the lip support portion 39. For this reason, when the internal lip deformation preventing member 23 is installed in the sealing device 13, the holding portions 48, 49, 50 that are in contact with the springless oil seal 24 of the internal lip deformation preventing member 23 are connected to the inner surface of the oil seal 24. It is comprised so that it may closely_contact | adhere to 43,44,45.

  As described above, also in the second embodiment, similarly to the first embodiment described above, it is possible to suppress the deformation of the oil seal by providing only one set of oil seals. The efficiency can be improved. Further, in the present embodiment, since the springless oil seal 24 is used, there is no need to remove the spring as in the case of using a spring-loaded oil seal, and the effect of facilitating manufacture can be obtained.

  FIG. 11 is an enlarged longitudinal sectional view showing another example of the sealing device 13 shown in FIG. The example shown in FIG. 11 is the same as that shown in FIG. 8 in that the springless oil seal 24 is used, but the external lip deformation preventing member 15 is different in the example shown in FIG. That is, the outer lip deformation preventing member 15 shown in FIG. 11 is not only provided with a circumferential oil supply groove 18 on its inner peripheral surface, but also the oil supply groove 18 and the lip portion 22 of the oil seal 24. An oil supply groove 26 in the axial direction connecting the sides is also provided. Also in this example, a plurality of the oil supply grooves 26 are formed in the circumferential direction of the inner surface of the outer lip deformation preventing member 15 as in the example of FIG.

  By configuring the external lip deformation preventing member 15 in this way, the lubricating oil supplied to the oil supply groove 18 is applied to the lip portion 22 of the oil seal 16 in the same manner as that described with reference to FIG. Since the oil can be supplied via the oil supply groove 26, the sliding friction loss can be reduced, the life of the oil seal 24 can be extended, and the compressor efficiency can be improved.

  According to each of the above-described embodiments, it has a pressure resistance function capable of suppressing deformation of the oil seal with only one set of oil seals without using two sets of oil seal devices as in the prior art, A screw compressor capable of improving the compressor efficiency can be obtained.

  In addition, this invention is not limited to the Example mentioned above, Various modifications are included.

Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment.
Further, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described.

DESCRIPTION OF SYMBOLS 1 ... Male rotor, 1b ... Male rotor suction | inhalation side axial part, 1c ... Male rotor discharge | emission side axial part,
2 ... Female rotor, 2b ... Female rotor suction side shaft portion, 2c ... Female rotor discharge side shaft portion,
3 ... casing, 4 ... motor housing,
5 ... D casing, 6 ... Suction filter, 7 ... Suction port,
8 ... Male rotor suction side bearing, 9 ... Female rotor suction side bearing,
10 ... male rotor discharge side bearing, 11 ... female rotor discharge side bearing,
12 ... Lip seal, 13 ... Sealing device, 14 ... Presser plate,
15 ... External lip deformation prevention member, 16 ... Oil seal (spring-loaded oil seal),
17 ... Internal lip deformation preventing member, 18 ... Oil supply groove, 19 ... Bush, 20 ... Oil supply hole,
21 ... Spring, 22 ... Lip part, 23 ... Internal lip deformation prevention member,
24. Oil seal (springless oil seal),
26 ... Oil supply groove, 31 ... Seal back portion outer surface holding portion,
33: Discharge end surface portion of the D casing, 33a: Discharge end surface,
34 ... sealed side (high pressure side), 35 ... non-sealed side (low pressure side),
37 ... outer periphery of the seal, 38 ... back of the seal, 39 ... lip support,
40 ... Lip front, 41 ... Lip rear, 42 ... Lip tip,
43 to 45 ... inner surface, 46 ... lip support portion outer surface holding portion, 47 ... lip rear surface holding portion,
48 ... Seal outer peripheral part inner surface holding part, 49 ... Seal back part inner surface holding part,
50 ... Lip part inner surface holding part, 51 ... Bearing chamber, 52, 53 ... Outer surface.

Claims (9)

A screw rotor having a rotor tooth portion, a suction side shaft portion and a discharge side shaft portion; a suction side bearing supporting the suction side shaft portion of the screw rotor; and a discharge side bearing supporting the discharge side shaft portion; A screw compressor comprising a casing for storing
A seal device for sealing the discharge side shaft portion between the discharge end surface side of the rotor tooth portion of the screw rotor and the discharge side bearing;
The sealing device includes an oil seal having a lip portion having a V-shaped cross section, and an external lip deformation preventing member that is provided on an outer surface of the oil seal and maintains the outer surface shape of the oil seal,
The oil seal has a lip support part for supporting the lip part, a seal back part connected to the lip support part, and a seal outer peripheral part connected to the seal back part,
The screw compressor according to claim 1, wherein the outer lip deformation preventing member is provided from the seal back surface portion to the lip portion of the oil seal.   The screw compressor according to claim 1, further comprising an internal lip deformation preventing member that is provided on an inner surface of the oil seal and maintains an inner surface shape of the oil seal.   2. The screw compressor according to claim 1, wherein the external lip deformation preventing member includes a circumferential oil supply groove provided on an inner peripheral surface thereof, and an axial oil connecting the oil supply groove and the lip portion side. 3. A screw compressor comprising a supply groove.   4. The screw compressor according to claim 3, wherein a plurality of the axial oil supply grooves are provided in a circumferential direction on an inner peripheral surface of the external lip deformation preventing member.   2. The screw compressor according to claim 1, wherein the oil seal is used in a state in which the spring of the spring-loaded oil seal is used by providing a spring on the outer peripheral side of the lip portion. Compressor.   2. The screw compressor according to claim 1, wherein the oil seal uses a springless oil seal without a spring on an outer peripheral side of the lip portion.   3. The screw compressor according to claim 2, wherein the outer lip deformation preventing member and the inner lip deformation preventing member are made of a material having high rigidity such as metal, composite resin, engineering plastic or the like. Machine.   The screw compressor according to claim 1, wherein the screw rotor is configured by meshing a pair of male and female rotors.   The screw compressor according to claim 1, wherein the screw compressor compresses the refrigerant flowing through the refrigeration cycle, and is configured in a hermetically sealed form.

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