JPH02275084A - Scroll vacuum pump - Google Patents

Abstract

PURPOSE:To aim at simplification for clearance control and low-unit cost of production by combining a rocking scroll eccentrically with a fixed scroll with an inlet port and an exhaust port at central and peripheral parts each, while interposing a seal ring between both these scrolls. CONSTITUTION:A fixed scroll 21 with a base plate 22 and a spiral body 23 is locked to the inside of an unillustrated pump casing via a bearing support 24, while an inlet port 24 and an exhaust port 25 are set up each to both the central and peripheral parts. Likewise, a rocking scroll 26 with a base plate 27 and a spiral body 28 is eccentrically combined with the fixed scroll 21, and combinedly installed in the bearing support 24 via a thrust receiver 29, while a ring groove for installing a seal ring 30 extending in the circumferential direction is formed in the peripheral edge. Then, a sealed space 32 moving toward an outer circumferential part from an inner circumferential apart is formed by the rocking scroll 26 and the fixed scroll 21.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a scroll vacuum pump equipped with a fixed scroll and an oscillating scroll.

[Conventional technology]

Conventionally, this type of scroll vacuum pump was developed in 1986.
It is disclosed in Japanese Patent No. 73577 and is configured as shown in FIG. This will be explained based on the same figure. In the same figure, the one indicated by reference numeral 1 is fixed to a bearing support 2 in the pump casing (not shown), and has a suction boat 3 and a discharge boat 4 at the outer circumference and the center, respectively. 5 is an oscillating scroll that is eccentrically combined with the fixed scroll 1 to form a closed space 6; 7 is a drive connected to the oscillating scroll 5 and provided on the bearing support 2 via a bearing 8; The shaft 9 is a balancer fixed to the drive shaft 7 and housed within the bearing support 2. Also, l
O is a pin crank that regulates the horizontal position of the swinging scroll 5 to prevent it from rotating, and 11 to 14 are thrust receivers that regulate the axial position of the swing scroll 5.

In the scroll vacuum pump configured in this way, the rotation of the drive shaft 7 causes the swinging scroll 5 to swing relative to the fixed scroll l.

At this time, the gas sucked between the scrolls 1 and 5 from the suction boat 3 is compressed in the closed space 6, and the gas is sucked into the discharge boat 4.
spit out from

By the way, in this type of scroll vacuum pump,
The thrust receivers 11 to 14 support the thrust force acting on the swinging scroll 5, and the swinging scroll 5
Stabilize the operating posture of the This is the oscillating scroll 5
This is because the back side of the scroll is maintained at suction pressure (vacuum pressure), so the swinging scroll 5 moves in a direction away from the fixed scroll 1. Furthermore, since bearings, bin cranks, etc. are installed in a vacuum, non-lubricated bearings and non-lubricated sliding members are used.

[Problem to be solved by the invention]

However, in the conventional scroll vacuum pump, the thrust receivers 11 to 14 are interposed between the fixed star roll 1 and the five swinging scrolls, and between the swinging scroll 5 and the bearing support 2. In addition to the function of supporting thrust loads against
It was necessary to maintain a function that would eliminate unstable operation. As a result, it is necessary to strictly set the clearance between each member, which poses a problem of complicating clearance management. In addition, since the fluid suction method employs a suction method in which the sealed space 6 moves from the outer circumference of the scroll toward the inner circumference of the scroll, when used as a dry scroll vacuum pump, the sliding members are not lubricated. There is also the problem that it needs to be formed using members, which increases costs.

Therefore, by setting the discharge pressure (atmospheric pressure) on the plywood back side of the oscillating scroll 5, the oscillating scroll 5 is pressed against the fixed scroll 1 side, and the posture of the oscillating scroll 5 during operation is stabilized. It is conceivable to use a lubricating member for the sliding part, but in this case a vacuum seal would be required between the fixed scroll 1 and the oscillating scroll 5.
This has the disadvantage of complicating the structure and increasing costs.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a scroll vacuum pump that can simplify clearance management and reduce costs.

[Means to solve the problem]

The scroll vacuum pump according to the present invention includes two scrolls that are provided in a casing and form a sealed space that moves from the inner circumference toward the outer circumference. It is composed of a fixed scroll having an exhaust port and an oscillating scroll eccentrically engaged with the fixed scroll, and a seal ring extending along the periphery is interposed between the two scrolls.

[For production]

In the present invention, fluid can be sucked in from the inner circumference of the scroll and discharged from the outer circumference of the scroll.

〔Example〕

EMBODIMENT OF THE INVENTION Hereinafter, the structure etc. of this invention will be explained in detail by the Example shown in the figure.

FIG. 1 is a sectional view showing a scroll vacuum pump according to the present invention, and FIGS. 2(a) and (bl) are plan views showing a fixed scroll and an oscillating scroll of the scroll vacuum pump according to the present invention. , 21 is a fixed scroll having a base plate 22 and a spiral body 23, which is fixed in a pump casing (not shown) via a bearing support 24, and has an intake boat at the center and outer circumference, respectively. 24 and an exhaust boat 25 are provided. 26 is an oscillating scroll having a base plate 27 and a spiral body 28, which is eccentrically combined with the fixed scroll 21 and is mounted on the bearing support 24 via a thrust receiver 29. An annular groove 31 is formed on the periphery to which a seal ring 30 extending in the circumferential direction is fitted.
The swinging scroll 26 is configured to form a sealed space 32 that moves together with the fixed scroll 21 from the inner circumference of the scroll toward the outer circumference of the scroll. 33 is a drive shaft having an oil supply passage 34 extending in the axial direction and a balance weight 35 protruding in the outer diameter direction;
It is rotatably provided in the pump casing (not shown) and inserted into the bearing support 24 via the main bearing 36, and the protrusion 26a of the swinging scroll 26 is attached to the swinging bearing 37 on the tip surface. A recessed portion 32a is provided to fit through the recessed portion 32a.

Further, 38 is an Oldham joint that prevents rotation of the oscillating scroll 26, and 39 is a base plate 2 of the fixed scroll 21.
2 and an end face seal interposed between the 28 spiral bodies of the oscillating scroll 26, the volute 23 of the fixed scroll 21, and the plywood 27 of the oscillating scroll 26; and 40, an end seal provided below the bearing support 24. A bearing support 41 is a sub-thrust support for supporting the drive shaft 33 on the bearing support 40, and 42 is an oil return hole provided in the bearing support 24. Note that the spiral body 23 of both scrolls 21°26
．． 28 prevents the flow rate from decreasing by removing about one round of the central part of the spiral body of a conventional scroll vacuum pump.

As shown in FIGS. 4(a) to 4(d), the scroll vacuum pump configured in this manner swings in the opposite direction to that of the conventional scroll vacuum pump, and draws fluid from the suction boat 24 on the inner circumference of the scroll. can be sucked in and discharged from the exhaust port 25 on the outer circumference of the scroll.

Therefore, in this embodiment, since the plywood back side of the oscillating scroll 26 can be maintained at the discharge pressure (atmospheric pressure) during operation, the spiral body side that receives this pressure and suction pressure (vacuum) or intermediate pressure The oscillating scroll 26 is pressed against the fixed scroll 21 by the differential pressure generated between the pressures,
It is possible to perform the swinging operation in a stable posture, and it is also possible to improve the oil sealing property between the fixed scroll 21 and the swinging scroll 26.

Further, the thrust receiver 29 used in this embodiment is
At the beginning of operation, axial fluid pressure and oscillating scroll 2
6, and also to position the swinging scroll 26 in the axial direction.
becomes unnecessary if both are combined.

Furthermore, in this embodiment, the inner and outer sides of the seal ring 3° (
Since the pressures (near the seal ring) are the same, the vacuum seal that was conventionally required when setting the back side of the oscillating scroll base plate to the discharge pressure is no longer necessary, and the seal ring 30 functions as an oil seal. It is good to have the following.

Although this embodiment shows an example in which the seal ring 30 is attached to the swinging scroll 26 side, the present invention is not limited to this, and even if the seal ring 30 is attached to the fixed scroll 21 side, the same applies to the embodiment. It has a similar effect.

〔Effect of the invention〕

As explained above, according to the present invention, the two scrolls are provided in the pump casing and form a sealed space that moves from the inner circumference toward the outer circumference. It consists of a fixed scroll each having an intake port and an exhaust port, and an oscillating scroll that engages eccentrically with the fixed scroll, and a seal ring extending along the periphery is interposed between these scrolls, so that from the intake port to Fluid can be sucked in and expelled through the exhaust port. Therefore, it is possible to maintain the plywood back side of the oscillating scroll at the discharge pressure during operation and eliminate unstable operation of the oscillating scroll, making it possible to strictly set the clearance between each member that was previously required. This is no longer necessary, and clearance management can be simplified.

In addition, the ability to transfer fluid from the inner circumference of the scroll toward the outer circumference of the scroll means that an oil seal can be used as a seal ring and a lubricating member can be used as a sliding member, which reduces costs. It is also possible to aim for

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a scroll vacuum pump according to the present invention, FIGS. ~(d) are diagrams for explaining its operating principle, and Figure 4 is a sectional view showing a conventional scroll vacuum pump. 21...Fixed scroll, 24...Intake hoard, 25... ...exhaust port, 26...oscillating scroll, 30...seal ring, 32...closed space. Agent Masuo Oiwa Figure 3 (d) (C) 270 deg 180 deg (b) 1. Request for flat display of the case @1-9374Ljt- 2. Name of the invention, Sufudare Vacuum Pump 3. Person making the amendment Representative 4, Representative 5. Details of the invention in the specification to be amended. Explanation Column 6, Contents of Amendment (1) “Figure 4” on page 7, line 15 of the specification has been changed to “Figure 3”
and correct it. (2) In the same book, p. 8, lines 12 to 16, "the function becomes unnecessary" is changed to "it is sufficient if the function is fulfilled, and the oscillating scroll 26 is always pressed against the fixed scroll 21 during steady operation." In other words, since the time when the function of the thrust receiver 29 is required is limited, the ring portion of the Oldham joint 39 may be made to have this function. Thrust receiver 2
9 can also be omitted.''that's all

Claims (1)

[Claims] Two scrolls are provided in the pump casing and form a sealed space that moves from the inner circumference toward the outer circumference, and these scrolls are replaced by a fixed scroll having an intake port and an exhaust port at the center and the outer circumference, respectively. , a scroll vacuum pump comprising an oscillating scroll eccentrically assembled with the fixed scroll, and a seal ring extending along the periphery is interposed between the two scrolls.