JP4256197B2 - Scroll decompression machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
According to the present invention, a fixed wrap in a fixed scroll provided in a housing and a turning wrap in a turning scroll pivotally supported on an eccentric shaft integrally formed with a drive shaft are engaged with each other, and the turning scroll has a constant eccentric amount with the drive shaft. The present invention relates to a scroll decompression machine including a scroll vacuum pump that is configured to compress and discharge gas sucked from an outer peripheral portion of a housing as it goes in the center direction.
[0002]
[Prior art]
The scroll decompression machine itself as described in the previous section is well known to those skilled in the art.
[0003]
In such a scroll decompression machine, when the operation time is extended for a long time, the temperature of the eccentric shaft integrated with the drive shaft, and the bearings and packings supporting the shafts rises, and eventually the bearings and packings are damaged. , May endure use.
[0004]
Therefore, in order to increase the durability of the scroll decompression machine, it is an essential requirement that the eccentric shaft integrated with the drive shaft does not become excessively high temperature even if it is operated for a long time.
[0005]
In order to meet such demands, the following measures have been taken in the past, and it is well known to those skilled in the art, not to mention references.
[0006]
(1) Low temperature or normal temperature air or nitrogen is introduced into the compression part of the scroll decompression machine to cool this part and dilute the toxicity of the gas in the compression part.
[0007]
(2) An axial ventilation hole was made in the drive shaft, and air of low temperature or normal temperature or nitrogen was discharged from the ventilation hole, passed through the bearing part, then sent into the compression part, and this part was cooled. Then, it is discharged together with the discharge gas.
[0008]
(3) The eccentric shaft integrated with the drive shaft is made hollow, and cold or normal temperature air is fed into it to cool the eccentric shaft.
[0009]
[Problems to be solved by the invention]
However, the above-described conventional technical means have the following problems.
In order to introduce low-temperature or normal-temperature air or nitrogen into the compression section, it is necessary to provide an introduction path for the inside and a means for supplying them to the outside. For this reason, the structure becomes complicated, the entire apparatus becomes larger, and the price increases.
[0010]
When the drive shaft is rotated, low-temperature or normal-temperature air or nitrogen is discharged from the vents provided in the drive shaft by centrifugal force, and the bearings and the like are cooled, but when the drive shaft is stopped, the compression unit In some cases, gas containing toxic gas or impurities flows backward and is released into the atmosphere through the vent hole, so that the surroundings are contaminated.
[0011]
In view of such problems in the prior art, the present invention utilizes a low-pressure region generated in a scroll decompression machine including a scroll vacuum pump in which a low-pressure region is generated in a housing during operation. The purpose is to improve the durability by cooling the eccentric shaft integrated with the drive shaft and its bearings and other peripheral members by automatically sucking the air. Is as follows.
[0012]
[Means for Solving the Problems]
(1) The fixed lap of the fixed scroll provided in the housing and the orbiting wrap of the orbiting scroll pivotally supported by the eccentric shaft integrated with the drive shaft are meshed with each other, and the orbiting scroll is revolved with a certain eccentric amount by the drive shaft. In the scroll decompression machine in which the gas sucked from the outer peripheral portion of the housing is compressed and discharged as it goes in the central direction, the drive shaft has a vent hole facing the axial direction, and the vent hole The valve hole is provided with a check valve that extends in the radial direction and is closed when the drive shaft is not rotating, but opens when the drive shaft rotates due to the centrifugal force associated therewith. The outer end of the direction is opened to a low pressure region in the compression chamber formed by meshing the fixed scroll and the orbiting scroll.
[0013]
(2) In the above item (1), the orbiting end plate of the orbiting scroll has a radially inner end interlocking with the radially outer end of the valve hole, and the radially outer end is a low pressure in the compression chamber. Air supply holes are provided in the region.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
In FIG. 1, the orbiting scroll is revolved with a certain amount of eccentricity in the housing, so that the gas sucked from the outer periphery of the housing is sucked into the compression part formed by combining the orbiting scroll and the fixed scroll, It is a vertical side view showing an example in which the present invention is applied to a scroll vacuum pump or a scroll decompression machine that is compressed from the center and then discharged from the center.
[0015]
(1) is a housing provided with a sealed disk-shaped compression chamber (2), which comprises a housing (3) and a lid (4), and is provided with a suction hole (1a) on the outer periphery. .
[0016]
Each of the housing (3) and the lid (4) has fixed end plates (3a) (4a) positioned opposite to both sides of the compression chamber (2). On the facing surface, spiral fixed wraps (3b) and (4b) are erected, and fixed scrolls (3c) and (4c) are formed.
[0017]
Between the fixed end plates (3a) and (4a), a turning scroll (5) is provided in the compression chamber (2) so as to be able to turn around the axis of the compression chamber (2).
[0018]
The orbiting scroll (5) is provided with upright orbiting wraps (5b) and (5b) that engage with and engage with the fixed scrolls (3c) and (4c) at 180 ° on both sides of the orbiting end plate (5a). The shaft (8a) of the drive shaft (8) fitted to the center of the housing (1) via bearings (6) and (7) is pivotally supported via bearings (9) and (10). Yes.
[0019]
The swivel end plates (5a) are arranged on the same circumference at equal intervals, and are connected to fixed end plates (3a) via three known pin crank type anti-rotation mechanisms not shown in FIG. When the drive shaft (8) rotates, the revolving end plate (5a) makes an eccentric revolving motion in the compression chamber (2), and the fixed wrap (3b) (4b) and the revolving wrap (5b ) In the radial direction of the space between them.
[0020]
As shown in FIG. 2, the pin crank type rotation prevention mechanism pivotally supports the main shaft (11a) of the pin crank (11) on the fixed end plate (3a) via the ball bearing (12), and Similarly, the crankshaft (11b) is pivotally supported by an appropriate bearing (14) fitted in a support hole (13) drilled near the outer periphery of the turning end plate (5a).
[0021]
At a location close to the center of the casing (4), the axial direction is directed, the inner end opens to a location near the center of the compression chamber (2), and the outer end is closed with a plug (15). A hole (16) is provided.
[0022]
The casing (4) is provided with a radial lead-out hole (17) extending from the outer peripheral surface to the through hole (16), and an exhaust joint is provided at the radial outer end of the lead-out hole (17). (18) is fitted.
The drive shaft (8) is driven by a motor (not shown), and at the position close to the outside of the housing (3) and the lid (4), the drive shaft (8) has a cooling fan ( 19) (20) is installed.
[0023]
Further, appropriate cooling fins (3d) and (4d) are projected from the outer surfaces of the housing (3) and the lid (4).
Further, in this embodiment, as a novel feature of the present invention, a vent hole (21) extending through the entire length of the drive shaft (8) and communicating with the outside air is penetrated at the center of the drive shaft (8) and driven. A valve hole (22) extending from the vent hole (21) to the outer peripheral surface is formed at the center in the axial direction of the thick portion of the eccentric shaft (8a) integrally formed with the shaft (8).
[0024]
Further, the revolving end plate (5a) extends in the radial direction from the outer end in the radial direction of the vent hole (21) via the annular communication path (24a), and the fixed wrap (3b) (4b) and the revolving wrap An air supply hole (24) that opens through a small-diameter outlet hole (23) is provided in a low-pressure region that is an intermediate portion in the radial direction of the compression chamber (2) formed by meshing (5b).
[0025]
In the valve hole (22), an appropriate check valve (25) that opens outward in the radial direction but does not open inward is fitted.
[0026]
Although the form of the check valve (25) is arbitrary, an example thereof is shown in FIG.
A small-diameter valve seat (22a) is formed at the radially inner end of the valve hole (22), and a step hole (22b) whose outer diameter is larger is provided at the outer end.
[0027]
A disc valve (26) is provided outside the valve seat (22a) in the valve hole (22), and a receiving plate (27) having an appropriate discharge hole (27a) is engaged outside the step hole (22b). It has stopped.
[0028]
The valve shaft (28) projecting radially outward from the center of the disc valve (26) is loosely fitted to the center of the receiving plate (27), and the disc valve (26) and the receiving shaft are supported. A compression cost spring (29) is fitted to the valve shaft (28) between the plates (27).
[0029]
In the scroll pressure reducing machine having such a configuration, the strength of the compression coil spring (29) of the check valve (25) is determined so as to achieve the purpose described later, and the disc valve (26) is closed. In this state, the suction hole (1a) is connected to a sealed container (not shown) to be evacuated or vacuumed, and the vent hole (21) provided in the drive shaft (8) is in communication with the outside air. Drive the drive shaft (8).
[0030]
Along with the rotation of the drive shaft (8), the orbiting scroll (5) pivotally supported by the drive shaft (8) revolves with a fixed amount of eccentricity while meshing with the fixed scrolls (3c) and (4c). The inside of the sealed container connected to the suction hole (1a) is successively depressurized, and a low pressure region is generated in a portion near the center of the meshing portion of the scroll (3c) (4c) (5) in the housing (1). .
[0031]
At this time, if the rotational speed of the drive shaft (8) becomes a certain value or more, the disc valve (26) of the check valve (25) provides a centrifugal force to resist the compression coil spring (29). Then move in the radial direction and open.
[0032]
Accordingly, the outside air is sucked into the low pressure region generated in the meshing part of the fixed / revolving scrolls (3c) (4c) (5) in the housing (1), and the vent hole (21) and the check valve (25). And through the annular communication passage (24a), the air flows into the air supply hole (24) and is discharged from the outlet hole (23) at the end thereof.
[0033]
Accordingly, the eccentric shaft (8a) of the drive shaft (8) and the bearings (9), (10), packings, etc. provided on the outer periphery thereof are cooled, and the durable life thereof becomes longer.
[0034]
Further, when the operation is stopped, the check valve (25) is automatically closed, so that there is no possibility that harmful gas accumulated in the low pressure region is released to the outside and pollutes the environment.
[0035]
Although the fixed scroll and the orbiting scroll in the embodiment are of the double-sided type, it goes without saying that the present invention can be equally applied to a single-sided type of scroll.
[0036]
【The invention's effect】
With the operation, the check valve opens, the outside air at low or normal temperature is automatically sucked into the low pressure area in the compression chamber, and the drive shaft and its surrounding bearings and other members are effectively cooled, so the service life is Extend.
[0037]
When the operation is stopped, the check valve (25) is automatically closed, so that no harmful gas accumulated in the low pressure region is released to the outside and the environment is not polluted.
[0038]
Furthermore, there is also an advantage that moisture in the compression chamber, grinding powder generated by operation, and the like are discharged together with the compressed gas by the gas flowing into the compression chamber through the check valve.
[Brief description of the drawings]
FIG. 1 is a longitudinal side view showing an embodiment of the present invention.
FIG. 2 is a longitudinal sectional view schematically showing the pin crank type rotation prevention mechanism in an exploded manner.
FIG. 3 is an enlarged longitudinal sectional view illustrating a check valve.
[Explanation of symbols]
(1) Housing
(1a) Suction hole
(2) Compression chamber
(3) Housing
(3a) Fixed end plate
(3b) Fixed wrap
(3c) Fixed scroll
(3d) Cooling fin
(4) Lid
(4a) Fixed end plate
(4b) Fixed wrap
(4c) Fixed scroll
(4d) Cooling fin
(5) Orbiting scroll
(5a) Revolving end plate
(5b) Swivel lap
(6) (7) Bearing
(8) Drive shaft
(8a) Eccentric shaft
(9) (10) Bearing
(11) Pin crank
(11a) Spindle
(11b) Crankshaft
(12) Ball bearing
(13) Support hole
(14) Bearing
(15) Embolization
(16) Through hole
(17) Lead hole
(18) Exhaust joint
(19) (20) Cooling fin
(21) Vent
(22) Valve hole
(22a) Valve seat
(22b) Step hole
(23) Outlet hole
(24) Air supply hole
(24a) Communication passage
(25) Check valve
(26) Disc valve
(27) Supporting plate
(27a) Discharge hole
(28) Valve stem
(29) Compression coil spring

Claims (2)

By meshing the fixed lap of the fixed scroll provided in the housing with the orbiting wrap of the orbiting scroll pivotally supported by the eccentric shaft that is integral with the drive shaft, and turning the orbiting scroll with a fixed eccentric amount with the drive shaft. In a scroll decompression machine that compresses and discharges the gas sucked from the outer periphery of the housing toward the center thereof, the drive shaft has a vent hole that faces in the axial direction, and a radial direction from the vent hole. The valve hole is provided with a check valve that is closed when the drive shaft is not rotating, but opens when the drive shaft rotates. An end is opened to a low pressure region in a compression chamber formed by meshing the fixed scroll and the orbiting scroll. Le vacuum machine. The orbiting end plate of the orbiting scroll is provided with an air supply hole whose inner end in the radial direction communicates with the outer end in the radial direction of the valve hole and whose outer end in the radial direction opens into a low pressure region in the compression chamber. The scroll decompression machine according to claim 1.

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