JPH08114188A - Dust seal device for scroll vacuum pump - Google Patents

Abstract

PURPOSE: To prevent a sealant of self-lubricity resin from being worn in a short time as a result of water or a solvent is a vacuum pump entering a dust seal device. CONSTITUTION: A resinous seal ring 32a having water resistance, and solvent resistance is fitted in the outer side of a groove 32c in the outer peripheral wall 11 of a fixed scroll and a resinous seal ring 32b having self-lubricity is fitted in the outside thereof. The seal rings 32a and 32b are pressed against the end plate 20a, with which the seal rings are brought into slide contact, of a revolving scroll 20 through the force of a rubber resilient body 32d inserted in the groove 32c.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a seal structure provided on the outer circumference of a pair of spiral wraps in an oilless scroll type vacuum pump.

[0002]

2. Description of the Related Art Conventionally, a technique for making a container vacuum is a vacuum pack used for packaging foods, a page (2) a vacuum car for sucking sludge and the like, and preventing heat conduction due to convection of air. For thermos, or medical,
It is widely used from general life to low-temperature technology such as industrial or experimental cooling and vacuumization of a container for storing a refrigerant. Further, a vacuum pump is used as a drying means after cleaning of a cleaning device that cleans using a hydrocarbon solvent, pure water, etc. as a measure against CFC regulations. That is, after washing with water or a hydrocarbon-based solvent, the object to be cleaned is placed in a closed container, and the inside of the closed container is evacuated to 100 ° C. or less in the closed container under negative pressure. Since the cleaning agent such as water is easily vaporized and discharged to the outside of the closed container together with air and other gases, the vacuum pump is also used as a drying means. Therefore, the number of cases where water and solvent enter the vacuum pump is increasing.

Therefore, recently, an oilless scroll type has attracted attention as a vacuum pump which is hardly affected by moisture and solvents. The operation of this oilless scroll type vacuum pump will be described with reference to FIG. It comprises a fixed scroll 10 having a first wrap 13 formed in a concave space surrounded by a peripheral wall 11, and an orbiting scroll 20 having a second wrap 21 which can be fitted into the first wrap 13. Without rotating the scroll 20
By revolving with respect to the fixed scroll 10, the volume of the closed space 22 formed between the both laps 13 and 21 is variable. Therefore, the orbiting scroll 20 is rotated at a constant radius around the center of the first wrap 13 of the fixed scroll 10 so that the contact points between the both wraps forming the closed space 22 functioning as a compression chamber sequentially move toward the center. By revolving the orbit, suction port 1
The gas taken in from 6 is taken into the closed space 22 formed by the both wraps 13 and 21 while wrapping around the winding end of the second wrap 21, and the volume thereof is successively reduced as the orbiting scroll 20 revolves. While being moved toward the center, the pressure is increased and the outer closed space 2
2 is discharged to the outside when conducting with the discharge port 17.

Page (3) In the above structure, it is extremely important to ensure the sealed state of the space 22 formed between the wraps 13 and 21 in order to improve the compression efficiency and the vacuum degree. Therefore,
A chip seal 31 made of a resin material having a self-lubricating property is interposed between sliding surfaces facing the axial end surface of the wrap. That is, the involute-shaped wrap 13 is provided on the opposite side of the disk-shaped end plate of the scroll member 10 (20) that functions as a fixed scroll or an orbiting scroll.
In addition to projecting (21), a lap groove 13a (21a) communicating from the central portion to the peripheral side is recessed on the end face side, and the tip seal 31 is continuously installed and fitted in this lap groove. . And the end plate 20 of the orbiting scroll 20
By a dust seal device 32 in which a dust seal member, which is a ring-shaped self-lubricating sealing member, is fitted in a groove portion that is provided on the outer peripheral wall 11 of the fixed scroll and is in contact with the outer periphery of a. The airtightness is maintained and the inhalation of air and dust from the outside is prevented.

In the scroll-type air compressor, the dust seal device 32 has a suction port on the outer circumference of the scroll, so that the differential pressure from the outside air pressure is very small, and a slight suction causes air compression. Therefore, it is mainly arranged to suppress the suction of impurities such as dust floating in the outside air. However, in the vacuum pump, as the airtightness of the closed container becomes equal to or lower than the atmospheric pressure, the suction port 16 also has the same negative pressure, and the pressure difference from the external pressure increases, so that the high sealing performance of the dust seal device is important. Is coming. Even if there is a slight leak, there is a problem that the degree of vacuum in the closed container cannot be obtained. Therefore, conventionally, as described above, it faces the outer peripheral portion of the end plate of the orbiting scroll 20,
A groove is formed on the outer peripheral wall 11 of the fixed scroll 10, only a self-lubricating seal member is fitted into the groove, and the end plate of the orbiting scroll is formed by an elastic member such as a spring inserted in the bottom of the groove. It is pressed against the sliding surface of to achieve a perfect seal. On the other hand, as for the water remaining in the vacuum container, when the pressure in the vacuum container decreases, for example page (4), if the water evaporated at 100 ° C and atmospheric pressure of 760 Torr is 20 ° C, It vaporizes at 17.5 torr to become water vapor, which is sucked into the vacuum pump. Then, by being compressed in the vacuum pump or cooled by a cooling fin, the vacuum pump remains in the state of condensed water or steam,
There is a lot of water.

[0006]

In the oilless scroll type vacuum pump described above, the condensed water or water vapor present in the vacuum pump is provided on the back surface of the end plate 20a provided with the wrap 21 of the orbiting scroll 20. The end plate surface is cooled by the fins 23, and condensed and adheres to the cooled end plate surface as water droplets. The attached water droplets are caused by the centrifugal force of the revolving scroll 20 or by the gravity of the water droplets on the end plate surface where the vacuum pump is placed horizontally and becomes vertical.
Penetrate into the dust seal device 32. The water or solvent that infiltrates the dust seal portion infiltrates the sliding surface of the self-lubricating seal material, promotes wear of the seal member, and causes a problem of poor sealing in a short time. The present invention is to shield this invading water or solvent with a resin having water resistance and solvent resistance so as not to directly enter the sliding surface of the self-lubricating seal member.

[0007]

SUMMARY OF THE INVENTION According to the present invention, an orbiting scroll that meshes with a fixed scroll at an angular displacement of about 180 degrees is revolved around a closed space formed between both scrolls while revolving. In an oilless scroll type vacuum pump that performs exhaust while sequentially reducing and moving from the suction port provided on the center to the discharge port provided on the center side, on the peripheral wall of the fixed scroll corresponding to the outer periphery of the end plate of the orbiting scroll. The seal member that fits into the groove of the pump is shielded with water- and solvent-resistant ring-shaped resin on the inside in order to shield water or solvent that enters from the inside of the pump, and the outer periphery is composed of a self-lubricating seal member. A dust seal device for a scroll vacuum pump, characterized in that a two-component seal ring fitted in the groove is integrally formed. And Page (5) which is constituted by two sealing rings separate each.

Then, in order to uniformly press the two-component seal ring fitted in the groove against the end plate surface of the orbiting scroll, an elastic member is inserted in the groove bottom portion to form a dust seal device for a scroll vacuum pump. Is.

[0009]

In the dust seal device of the scroll vacuum pump configured as described above, the water vapor or solvent vapor taken in from the closed container for vacuum drying or the like is liquefied in the vacuum pump, and is laid on the outer peripheral wall of the fixed scroll. A resin seal ring having water resistance and solvent resistance is provided inside the groove on the outer peripheral wall of the fixed scroll in order to prevent penetration of the provided dust seal portion and promotion of wear of the seal member. Water that intrudes from the inside of the vacuum pump by integrating a resin seal ring having self-lubricating properties on its outer peripheral side or by fitting as two seal ring members,
Alternatively, the solvent is sealed with a water-resistant and solvent-resistant resin seal ring to prevent the water and the like from entering the resin seal ring portion having self-lubricating property on the outer peripheral portion.

The water-resistant and solvent-resistant resin seal ring has relatively high hardness and excellent wear resistance, but the sealability is not perfect. That is, there is a drawback that the sealability against liquids such as water is maintained, but the sealability against gases such as air is incomplete. On the other hand, the characteristic of the self-lubricating resin seal ring fitted on the outer peripheral side is that it is relatively soft and is completely pressed against the end plate surface of the orbiting scroll to completely seal gas such as air, A material with low dynamic resistance.

A ring-shaped rubber elastic body having the two-component resin seal ring inserted in the bottom of the circumferential groove on the outer peripheral wall of the fixed scroll is uniformly pressed on the end plate surface of the orbiting scroll. Then, the liquid (such as water) from the inside of the vacuum pump is prevented from entering the sliding surface (6), and the suction of gas such as air from the outside is completely sealed, resulting in a durable dust seal device. Is.

[0012]

EXAMPLES The present invention will be described in detail below with reference to the examples shown in the drawings. However, the dimensions, materials, shapes, relative positions, etc. of the components described in this embodiment are merely examples of explanations, not the intention to limit the scope of the present invention thereto, unless otherwise specified. .

FIG. 3 is a basic configuration diagram according to the present invention.
In the figure, the vacuum pump 1 is connected to a rotating shaft of a motor 5 via a pulley 42 and a belt 34, and the rotation of the motor 5 drives the orbiting scroll in the vacuum pump body 1 to seal it via a pipe 4. The gas in the container 7 is sucked out and the closed container 7 is evacuated.

FIG. 1 shows an oilless scroll type vacuum pump according to the present invention, which comprises a fixed scroll 10, an orbiting scroll 20, and a frame 40 which supports these at a predetermined position or rotatably as described above. .
The fixed scroll 10 is fixed to the end surface of the frame,
A spiral wrap 13 is formed upright in a concave space surrounded by a peripheral wall 11 having a port 16 functioning as a suction port, and a discharge port 17 for discharging compressed gas is provided at the substantially center thereof. There is. The orbiting scroll 20 is housed in the recessed space in the frame 40,
An end plate 20 in which a spiral wrap 21 having substantially the same shape as the wrap 13 of the fixed scroll 10 abuts on the peripheral wall 11.
The wrap 1 is formed upright on one surface of a.
3, 21 are fitted together.

Cooling fins 33 and 23 are formed on the back sides of the scrolls 10 and 20, respectively, so that the inside of the scrolls can be cooled by air cooling. Page (7) The wraps 13 and 21 of each scroll are provided with groove portions 13a and 21a, which are recessed in the end faces that come into contact with the scrolls on the other side,
A self-lubricating seal member 31 is fitted therein so that it can slide without lubrication. The end plate 20a of the orbiting scroll 20 and the fixed scroll 1 that abuts on the outer circumference of the end plate 20a.
Dust seal device in which a ring-shaped sealing member made of two components, a resin having water resistance and solvent resistance inside the groove formed on the outer peripheral wall 11 of 0 and a resin having self-lubricity outside the groove, is fitted. 32 is provided to achieve airtightness between the inside of the concave space 12 and the outside, and prevents the inhalation of gas such as air from the outside.

On the other hand, the frame 40 has a pulley 42 at one end.
The main drive crankshaft 41 attached with the shafts is pivotally supported along the central axis, and the driven crankshaft 43 is pivotally supported at positions displaced by 120 degrees about the main drive crankshaft 41 (three locations). I am letting you. Each of these crankshafts 41, 43 is rotatably supported by a housing body 25 integrated with the orbiting scroll 20.
The orbiting scroll 20 is configured to be able to revolve around the wrap center of the fixed scroll 10 at a constant radius while being prevented from rotating by the drive rotation of the main drive crankshaft 41. A pipe 4 is connected to the suction port 16, and its tip is connected to the closed container 7 shown in FIG.

FIG. 2 is a detailed sectional view of the dust seal device 32 having a ring-shaped sealing member fitted therein, which is also the subject matter of the present invention. In the figure, A indicates the inside of the vacuum pump, and B
Indicates the atmosphere side. Reference numeral 32c is a groove that is circumferentially recessed on the outer peripheral wall 11 of the fixed scroll 10. 32b is a seal ring disposed inside the vacuum pump, and a seal ring 32b
Is a resin having water resistance and solvent resistance, and in one example, it is a high-density polyethylene resin molded into a ring having a rectangular cross section. Reference numeral 32a denotes a self-lubricating seal ring disposed on the outside of the groove, that is, on the atmosphere side.
Page (8) Molded into a ring with a rectangular cross section. The seal rings 32a and 32b can be integrally formed and fitted by adhesion, fitting, or the like, or can be fitted individually as separate bodies. An elastic body 32d for pressing the seal rings 32a and 32b against the end plate 20a surface of the orbiting scroll 20 is inserted in the groove bottom. The elastic body 32d is formed by a tubular ring having a hollow inside. With this elastic body 32d, the end plate 2
0a surface to seal the sliding surface and to leak through the inner wall of the groove and the seal rings 32a and 32b.
The fixed portion of the contact surface between the elastic body 32d and the elastic body 32d is sealed. Here, as the elastic body 32d, a rubber elastic material is used as an example, but the elastic material is not limited to the rubber material as long as it is an elastic material. Reference numeral 32 denotes the entire structure of the dust seal device including the above members.

[0018]

As described above, in a scroll vacuum pump used for applying a vacuum to the inside of a closed container to perform drying, the vapor accompanying the gas to be sucked is liquefied in the vacuum pump to form water or a solvent. When it enters the dust seal device, it is shielded by the water-resistant and solvent-resistant seal ring 32b, and prevents the self-lubricating seal ring 32a from entering, thereby maintaining the original sealability of the seal ring 32a for a long time. Thus, the durability of the dust seal device is improved by several steps.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a scroll vacuum pump according to the present invention.

FIG. 2 is a detailed cross-sectional view of a main part of a dust seal device according to the present invention.

FIG. 3 is a schematic diagram showing an example of a basic configuration of the present invention.

[Explanation of symbols]

1 Oilless scroll type vacuum pump main body Page (9) 7 Closed container 10 Fixed scroll 11 Fixed scroll peripheral wall 16 Suction port 17 Discharge port 20 Orbiting scroll 20a End plate 31 Self-lubricating seal member 32 Dust seal device 32a Seal ring (self-lubricating) Resin) 32b Seal ring (water resistant, solvent resistant resin)

Claims (3)

[Claims] 1. A closed space formed between both scrolls while revolving a revolving scroll engaged with a fixed scroll at an angle of approximately 180 degrees is centered from an intake port provided on the outer peripheral side. In the oilless scroll type vacuum pump that performs exhaust while sequentially reducing and moving toward the discharge port provided on the side, a seal member that fits into a groove on the peripheral wall of the fixed scroll corresponding to the outer circumference of the end plate of the orbiting scroll is provided. , Water resistant inside, to shield water or solvent entering from inside the vacuum pump,
A dust seal device for a scroll vacuum pump, characterized in that it is shielded by a solvent-resistant ring-shaped resin, and its outer periphery is constituted by a self-lubricating seal member. 2. A seal member fitted into a groove on a peripheral wall of a fixed scroll corresponding to the outer circumference of an end plate of the orbiting scroll is made of a water-resistant and solvent-resistant ring-shaped resin, and the outer circumference is self-lubricating. 2. A dust seal device for a scroll vacuum pump according to claim 1, wherein said two seal rings are ring-shaped resin. 3. An elastic member is inserted at the bottom of the groove in order to press the seal member fitted into the groove on the peripheral wall of the fixed scroll corresponding to the outer circumference of the end plate of the orbiting scroll against the end plate surface. 1. A dust seal device for a scroll vacuum pump according to 1.