JP4044311B2 - Air-cooled scroll fluid machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an air-cooled scroll fluid machine such as a scroll compressor and a scroll vacuum pump.
[0002]
[Prior art]
When the scroll compressor is used as an air compressor, the fixed and orbiting scroll becomes high temperature due to the compression heat of air generated between the fixed lap and the orbiting lap, and the durability is impaired.
[0003]
In order to deal with this problem, an air-cooled scroll compressor has been proposed as described in, for example, Japanese Utility Model Publication No. 7-38717, Japanese Patent Application Laid-Open No. 2001-123969, and the like.
[0004]
These are formed between adjacent cooling fins by arranging a plurality of cooling fins at predetermined intervals on the outer surface of the fixed end plate of the fixed scroll and the inner surface of the orbiting scroll. By forcibly sending outside air to the cooling passage communicating from one side to the other by a cooling fan or the like, heat is exchanged between the cooling air and each cooling fin so as to suppress the temperature rise of the fixed and orbiting scroll. ing.
[0005]
[Problems to be solved by the invention]
However, in the air-cooled scroll compressor as described above, the following problems may occur.
That is, the scroll compressor has a characteristic that the compression ratio becomes higher toward the center of the fixed and swirl lap, so that the central portion becomes high temperature. For this reason, the temperature of the air passing through the cooling passage between the cooling fins is low on the upstream side, but gradually increases due to heat exchange with the cooling fins from the central portion toward the downstream side.
Therefore, since the fixed and orbiting scroll located on the upstream side is effectively cooled, the coefficient of thermal expansion of the fixed and orbiting wrap is small, and there is no possibility of causing any problems.
[0006]
However, since the fixed and orbiting scroll located on the downstream side is cooled by the cooling air having a high temperature after heat exchange, the cooling effect is small, and the thermal expansion coefficient of the fixed and orbiting wrap is smaller than that of the upstream side. Also grows. This phenomenon is particularly likely to occur during installation in summer and in places with high ambient temperatures.
[0007]
In this case, in order to increase the compression efficiency, the gap between the fixed wrap and the swirl wrap is usually made as small as possible. It may reduce the compression efficiency and damage the wrap.
[0008]
The present invention has been made in view of the above problems, and even if the cooling effect of the fixed and orbiting scroll is small on the downstream side of the cooling passage, the fixed wrap and the orbiting wrap can be brought into contact by thermal expansion. An object of the present invention is to provide an air-cooled scroll type fluid machine that is excellent in durability and reliability.
[0009]
[Means for Solving the Problems]
According to the present invention, the above problem is solved as follows.
(1) A fixed scroll fixed in the housing and having a suction hole and a discharge hole in the outer peripheral portion and the central portion, respectively, and a spiral fixed wrap projecting on one side surface, and opposed to the fixed scroll And a revolving scroll having a spiral revolving wrap protruding on one side surface and fitted to the fixed wrap, and the housing is provided with a ventilation opening facing each other. A cooling passage formed between the two ventilation openings is disposed on at least one of the other side surfaces of the fixed scroll and the orbiting scroll, and the inside of the cooling passage is fed from the one ventilation opening. An air-cooled scroll type that cools at least one of the fixed scroll and the orbiting scroll by circulating the cooling air. In the body machine, the radial gap between the fixed wrap and the swirl wrap is reduced by slightly reducing the thickness of the fixed wrap or swirl wrap located downstream of the discharge hole in the cooling passage. The gap is slightly larger than the gap between the fixed wrap and the swivel wrap located on the upstream side of the hole.
[0010]
(2) In the above item (1), the radial gap between the fixed wrap located on the downstream side and the turning wrap is made 30 to 50 μm larger than the gap between the upstream fixed wrap and the turning wrap.
[0011]
(3) In the above item (1) or (2), the radial gap between the fixed wrap located on the downstream side and the turning wrap is maximized in the vicinity of the central portion of the cooling passage.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a longitudinal side view of a main part of a single-roll two-stage scroll type air compressor which is an example of an air-cooled scroll type fluid machine of the present invention, and FIG. 2 is a longitudinal rear view taken along line II-II in FIG. 3 is a longitudinal rear view taken along the line III-III in FIG.
[0013]
In FIG. 1, the scroll body (1) includes a fixed scroll (2) and a turning scroll (3) driven by a motor (not shown) housed outside or inside, and the fixed scroll (2) is a disc. A plurality of cooling fins (5) for allowing cooling air to pass through the front surface (which will be described below with the left side of FIG. 1 as the front) as one side surface of the fixed end plate (4) having a suitable shape. In addition, a spiral (involute) fixed wrap (6) is formed on the rear surface which is the other side surface so as to project in the axial direction.
[0014]
On the front surface of the disc-shaped orbiting end plate (7) in the orbiting scroll (3), the involute-shaped low-pressure orbiting wrap (8) and the high-pressure orbiting wrap (9) are centered on the high-pressure orbiting wrap (9). The concentric and discontinuous projections are positioned at the center, and both swirl wraps (8) and (9) are engaged with the fixed wrap (6).
[0015]
As shown in FIG. 3, a plurality of corrugated cooling fins (10) facing in the left-right direction for allowing cooling air to pass therethrough are provided at the rear surface of the swivel end plate (7) with appropriate intervals in the vertical direction. Projecting.
[0016]
The cooling fins (5) projecting from the fixed end plate (4) are also oriented in the same direction as the cooling fins (10), and the left and right side surfaces of the fixed scroll housing (11) and the drive shaft housing (12). A cooling passage (A) is formed between the air outlet and the ventilation hole (not shown) on the fixed scroll housing (13). Both cooling fins (5) and (10) are cooled by blowing with a cooling fan or the like from one of the ventilation openings (13), for example, from the left side in FIG.
[0017]
A bearing plate (14) is bolted to the rear end surface of the orbiting scroll (3), and an eccentric shaft of a drive shaft (15) linked to a rotating shaft (not shown) such as a motor is centrally located on the rear surface. A cylindrical boss (18) fitted through a bearing (17) protrudes from the part (16).
[0018]
Between the orbiting scroll (3) and the housing (12) in which it is housed, three known crankpin type anti-rotation mechanisms (19) for preventing the orbiting scroll (3) from rotating. The orbiting scroll (3) can be rotated clockwise with a predetermined amount of eccentricity relative to the fixed scroll (2).
[0019]
At the time of this turning, between the turning scroll (3) and the fixed scroll (2), that is, the outer peripheral surface of the low pressure turning wrap (8) and the inner peripheral surface of the fixed wrap (6), and the high pressure turning wrap (9 ) Between the outer peripheral surface and the inner peripheral surface of the fixed wrap (6), the two-stage compression chambers of the low-pressure compression chamber (20) and the high-pressure compression chamber (21) whose volume gradually decreases toward the center. Is formed. Each of these compression chambers (20) and (21) is partitioned by a partition wall (22) provided at an intermediate portion of the fixed wrap (6).
[0020]
The outer periphery of the fixed scroll (2) is provided with an air suction hole (23) so that outside air that has passed through a filter (not shown) is sucked into the low-pressure compression chamber (20).
[0021]
A discharge hole (24) communicating with the high-pressure compression chamber (21) is formed in the center of the fixed end plate (4), and this discharge hole (24) is not shown via the discharge pipe (25). It is connected to an air tank or air tool.
[0022]
Further, on both sides of the fixed end plate (4) across the partition wall (22), a low pressure side discharge port (26) communicating with the low pressure compression chamber (20) and a high pressure side suction port communicating with the high pressure compression chamber (21). (27) is drilled.
[0023]
As shown in FIG. 1, the low-pressure side discharge port (26) is connected to the inlet side of the intermediate cooler (29) via a conduit (28), and the high-pressure side suction port (27) is connected to a conduit ( It is connected to the outlet side of the intercooler (29) via 30).
[0024]
The fixed scroll (2) has a pressing plate (31) secured to the front surface thereof with bolts (32), and the fixed scroll housing (11) has a tightening screw (33) at the front end opening of the drive shaft housing (12). By being fixed, it is integrally assembled on the orbiting scroll (3) side.
[0025]
The low-pressure swirl wrap (8) on the downstream side of the cooling passage (A) in the swirl roll (3), that is, the right-half swivel wrap (8) centered on the discharge hole (24) formed in the center in FIG. In the wrap (9), the thickness (t) of the portion located near the center of the cooling passage (A) is the thickness of the other portion, particularly the left half (upstream of the cooling passage (A)) ( It is slightly larger than t ₀ ).
[0026]
As a result, the radial gap between the outer peripheral surface of the low-pressure swirl wrap (8) and the high-pressure swirl wrap (9) and the inner peripheral surface of the fixed wrap (6) is thinner than the other parts. It is slightly larger (exaggerated in the figure).
[0027]
This is because the temperature of the air passing through the cooling passage (A) increases as it goes from the center toward the downstream side, as described in the above section “Problems to be Solved by the Invention”. This is to cope with the problem of thermal expansion of the fixed wrap (6) and the orbiting wraps (8) and (9) caused by the reduced cooling effect of the fixed scroll (2) and the orbiting scroll (3).
[0028]
That is, if the low-pressure swirl wrap (8) on the downstream side having a large coefficient of thermal expansion and the gap between the high-pressure swirl wrap (8) and the fixed wrap (6) are increased in advance by an amount corresponding to the thermal expansion coefficient. , They can solve the problem of contact.
[0029]
For example, when the upstream gap is 40 to 50 μm in a general compressor having high versatility, the gap is preferably 30 to 50 μm larger than that and preferably 70 to 100 μm. If it is less than 70 μm, the thermal expansion cannot be completely absorbed, and the swirl wrap (8) (9) may come into contact with the fixed wrap (6). If it exceeds 100 μm, the swirl wrap (8) (9) ) And the fixed wrap (6) is too large to reduce the compression efficiency by experiments.
[0030]
The compression temperature of the air is highest in the vicinity of the discharge hole (24), which is the central portion, and the temperature of the cooling air passing through that portion is also high, so that the thickness of the swirl wrap (8) (9) ( t) is gradually thinned so as to be minimized at the center of the cooling passage (A), and the radial gap between the fixed wrap (6) and the swirling wrap (8) (9) is the center of the cooling passage (A). It is better to make it as large as the part.
[0031]
As in the above embodiment, the wall thickness of the swirl wraps (8) and (9) located on the downstream side of the cooling passage (A) having a small cooling effect and a high thermal expansion coefficient is made thin over a required range and fixed. If the radial gap with the wrap (6) is set to be slightly larger than the regular gap, even when the compressor is used under a high ambient temperature condition, both the swirl wraps (8) (9 ) And the fixed wrap (6) can be prevented from contacting each other on the downstream side of the cooling passage (A).
[0032]
Therefore, they are worn out to increase the gap, thereby preventing the compression efficiency from being lowered and the wrap from being damaged.
[0033]
Further, since the contact between the swivel wraps (8) and (9) and the fixed wrap (6) is prevented, it becomes possible to reduce the amount of cooling air blown by a cooling fan or the like, and the consumption of the motor for driving the same. Economical effects such as saving electric power and using a small motor can be obtained.
[0034]
The present invention is not limited to the above embodiment.
In the above embodiment, the low-pressure and high-pressure swirl wraps (8) and (9) are thin, and the clearance between the fixed wrap (6) is large. You may make it the thickness of the side thin, and make the clearance gap of radial direction between it and a turning wrap (8) (9) slightly large.
[0035]
Further, in the above embodiment, the cooling passage (A) is directed to the left and right sides of the compressor casings (11) and (12) by opening the vent holes (13) so that the cooling passages (A) face the left and right directions. 3 is made to flow from the left to the right in FIG. 3, but on the contrary, the cooling air is made to flow from the right to the left, or the position of the vent (13) is changed. The direction of the cooling passage (A) may be changed. In any case, the swirl wrap (8) (9) or the fixed wrap (6) located on the downstream side of the cooling air is made thin, What is necessary is just to make the clearance gap between them large.
[0036]
The present invention is not limited to the above-described single-winding two-stage scroll air compressor, but a single-wrap scroll (one-stage) compressor, or a double-wrap scroll having swirl wraps on both sides of an end plate of the orbiting scroll. The present invention can also be applied to a (single stage, multistage) type compressor or the like.
[0037]
【The invention's effect】
According to the present invention, the following effects can be achieved.
(A) According to the first aspect of the present invention, the cooling effect of the fixed scroll or the orbiting scroll is small on the downstream side of the cooling passage, and even if the fixed wrap or the orbiting wrap thermally expands, there is no fear that they contact. Both wraps are prevented from being worn or damaged.
In addition, since it is possible to reduce the air volume by a cooling fan or the like, it is possible to save power consumption of the drive motor or the like, and to reduce the size of the motor, which is economical.
[0038]
(B) According to the invention of claim 2, the thermal expansion of the fixed or swirling wrap can be effectively absorbed without reducing the compression efficiency.
[0039]
(C) According to the invention described in claim 3, for example, even if the atmospheric temperature is high and the temperature of the air passing through the central portion of the cooling passage becomes high, the fixed wrap and the swirl wrap are in the central portion of the cooling passage. Is prevented from touching.
[Brief description of the drawings]
FIG. 1 is a central longitudinal side view of a main part showing an embodiment of the present invention.
2 is an enlarged longitudinal rear view taken along the line II-II in FIG.
3 is an enlarged vertical rear view taken along line III-III in FIG.
[Explanation of symbols]
(1) Scroll body
(2) Fixed scroll
(3) Orbiting scroll
(4) Fixed end plate
(5) Cooling fin
(6) Fixed wrap
(7) Revolving end plate
(8) Low-pressure swirl wrap
(9) High-pressure swirl wrap
(10) Cooling fin
(11) Fixed scroll housing
(12) Drive shaft housing
(13) Ventilation opening
(14) Bearing plate
(15) Drive shaft
(16) Eccentric shaft
(17) Bearing
(18) Cylindrical boss
(19) Automatic prevention mechanism
(20) Low pressure compression chamber
(21) High pressure compression chamber
(22) Bulkhead
(23) Suction hole
(24) Discharge hole
(25) Discharge pipe
(26) Low pressure side outlet
(27) High pressure side inlet
(28) Conduit
(29) Intermediate cooler
(30) Conduit
(31) Press plate
(32) Bolt
(33) Tightening screw
(A) Cooling passage

Claims (3)

A fixed scroll which is fixed in the housing and has a suction hole and a discharge hole in the outer peripheral portion and the central portion, respectively, and a spiral fixed wrap projecting on one side surface, and so as to face this fixed scroll A swivel scroll provided in a swivel manner and provided with a swirl-shaped swirl wrap that fits with the fixed wrap on one side surface, and the housing is provided with ventilation openings facing each other; A cooling passage formed between these ventilation openings is disposed on at least one of the other side surfaces of the fixed scroll and the orbiting scroll, and the cooling air is supplied from the one ventilation opening in the cooling passage. An air-cooled scroll fluid machine that cools at least one of the fixed scroll and the orbiting scroll In,
By making the wall thickness of the fixed wrap or swirl wrap positioned downstream of the discharge hole in the cooling passage slightly thinner, the radial gap between the fixed wrap and swirl wrap is made smaller than the discharge hole. An air-cooled scroll type fluid machine characterized in that it is slightly larger than the gap between the fixed wrap and the swivel wrap located on the upstream side. The air-cooled scroll type fluid machine according to claim 1, wherein a radial gap between the fixed wrap and the swivel wrap located on the downstream side is made 30 to 50 µm larger than a gap between the fixed wrap and the swirl wrap on the upstream side. . The air-cooled scroll fluid machine according to claim 1 or 2, wherein a radial gap between the fixed wrap and the swirl lap located on the downstream side is maximized in the vicinity of the center portion of the cooling passage.

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