JP2003097462A - Air-cooled scroll fluid machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the contact of a mutual fixed lap and a turning lap even if cooling effects of fixed and turning scrolls are small in the downstream of a cooling passage. SOLUTION: In an air-cooled scroll compressor, each thickness of the turning laps 8 and 9 positioned on the downstream of a discharge hole 24 in the cooling passage is thinned a little so that a radial directional clearance between the fixed lap 6 and the turning laps 8 and 9 is formed a little larger than a clearance between the fixed lap 6 and the turning laps 8 and 9 positioned on the upstream of the discharge hole 24.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air-cooled scroll type fluid machine such as a scroll type compressor or a scroll type vacuum pump.

[0002]

2. Description of the Related Art When a scroll type compressor is used as an air compressor, the heat of compression of air generated between a fixed wrap and an orbiting wrap causes the fixed and orbiting scrolls to become hot and impairs their durability.

In order to deal with this problem, an air-cooled scroll type compressor has been proposed as described in, for example, Japanese Utility Model Publication No. 7-38717 and Japanese Patent Laid-Open No. 2001-123969.

In these devices, a plurality of cooling fins are juxtaposed at predetermined intervals on the outer surface of the fixed end plate of the fixed scroll and the inner surface of the orbiting end plate of the orbiting scroll, and between adjacent cooling fins. By forcing the outside air into the formed cooling passage that communicates from one side to the other with a cooling fan or the like, heat is exchanged between the cooling air and each cooling fin to increase the temperature of the fixed scroll and the orbiting scroll. I try to keep it down.

[0005]

However, the following problems may occur in the air-cooled scroll type compressor as described above. That is, the scroll-type compressor has a characteristic that the compression ratio becomes higher toward the center of the fixed and orbiting wraps, so that the central portion becomes hot.
Therefore, the temperature of the air passing through the cooling passage between the cooling fins is low on the upstream side, but gradually rises due to heat exchange with the cooling fins from the central portion toward the downstream side. Therefore, since the fixed and orbiting scrolls located on the upstream side are effectively cooled, the coefficient of thermal expansion of the fixed and orbiting laps of that portion is small, and there is no possibility of causing any problems.

However, since the fixed and orbiting scrolls located on the downstream side are cooled by the cooling air having a high temperature after heat exchange, the cooling effect is small, and the coefficient of thermal expansion of the fixed and orbiting wraps is It becomes larger than the upstream side. This phenomenon is likely to occur especially in summer or when installed in a place where the ambient temperature is high.

In this case, the gap between the fixed wrap and the orbiting wrap is usually made as small as possible in order to improve the compression efficiency. It can wear and reduce compression efficiency and damage the wrap.

The present invention has been made in view of the above problems, and even if the cooling effect of the fixed scroll and the orbiting scroll is small on the downstream side of the cooling passage, the fixed wrap and the orbiting wrap contact each other due to thermal expansion. It is an object of the present invention to provide an air-cooled scroll type fluid machine which is excellent in durability and reliability.

[0009]

According to the present invention, the above problems can be solved as follows. (1) A fixed scroll that is fixed in the housing, has a suction hole and a discharge hole in the outer peripheral portion and the central portion, and has a spiral fixed wrap projecting from one side surface, and faces the fixed scroll. And a swirl scroll provided on one side with a spiral swirl wrap that fits with the fixed wrap in a protruding manner, and the housing has a ventilation port facing each other. And a cooling passage formed between these two ventilation openings is disposed on at least one of the other side surfaces of the fixed scroll and the orbiting scroll, and the cooling passage is fed from the one ventilation opening. An air-cooled scroll type in which at least one of the fixed scroll and the orbiting scroll is cooled by circulating cooling air. In the body machine, by slightly reducing the wall thickness of the fixed wrap or the swivel wrap located on the downstream side of the discharge hole in the cooling passage, the radial gap between the fixed wrap and the swirl wrap is discharged. It is slightly larger than the gap between the fixed wrap and the swivel lap located upstream of the hole.

(2) In the above item (1), the radial gap between the fixed wrap located on the downstream side and the swivel lap is 30 times smaller than the gap between the fixed wrap on the upstream side and the swivel lap.
Increase by ~ 50 μm.

(3) In the above item (1) or (2), the radial gap between the fixed wrap and the swirling lap located on the downstream side is maximized near the center of the cooling passage. .

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a vertical sectional side view of a main part of a single-winding two-stage scroll type air compressor which is an example of the air-cooled scroll type fluid machine of the present invention, and FIG. 2 is a vertical sectional rear view taken along line II-II of FIG. Similarly, FIG. 3 is a vertical cross-sectional rear view taken along the line III-III of FIG. 1.

In FIG. 1, the scroll body (1) comprises a fixed scroll (2) and an orbiting scroll (3) driven by a motor (not shown) housed outside or inside, and the fixed scroll (2) is , A plurality of cooling fins for passing cooling air to a front surface (which will be described below with the left side of FIG. 1 as the front), which is one side surface of the disk-shaped fixed end plate (4).
(5) is provided so as to project at an appropriate interval, and a spiral wrap (fixing wrap) is provided on the other side, the rear surface.
(6) is formed by projecting in the axial direction.

On the front surface of the disk-shaped orbiting end plate (7) of the orbiting scroll (3), there are an involute-shaped low-voltage orbiting wrap (8) and a high-voltage orbiting wrap (9).
Concentric and discontinuously projecting forward with the (9) positioned in the center, and both turning laps (8) and (9) are fixed wraps as described above.
It is engaged with (6).

As shown in FIG. 3, a plurality of corrugated plate-shaped cooling fins (10) oriented in the left-right direction for passing cooling air are vertically provided on the rear surface of the swirling end plate (7). It is projected at intervals.

The cooling fins (5) projecting from the fixed end plate (4) are also oriented in the same direction as the cooling fins (10).
Fixed scroll housing (11) and drive shaft housing (1
The cooling passage is formed between the ventilation holes (not shown on the fixed scroll housing side) formed on both left and right sides of (2) so as to face each other.
(A) is formed. One of the ventilation openings (13), for example, FIG.
Both cooling fins (5) and (10) are cooled by blowing air from the left side of the cooling fan or the like.

A bearing plate is provided on the rear end surface of the orbiting scroll (3).
(14) is bolted, and at the center of its rear surface, through a bearing (17), to an eccentric shaft portion (16) of a drive shaft (15) linked to a rotary shaft (not shown) of a motor or the like. The fitted cylindrical boss (18) is projected.

Between the orbiting scroll (3) and the housing (12) in which it is housed, three sets of known crankpin type antirotation mechanisms for preventing the orbiting scroll (3) from rotating. (19) is incorporated, orbiting scroll (3)
Can rotate clockwise with respect to the fixed scroll (2) with a predetermined eccentric amount when viewed from the rear.

At the time of this turning, the turning scroll (3)
And the fixed scroll (2), that is, the outer peripheral surface of the low pressure orbiting wrap (8) and the inner peripheral surface of the fixed wrap (6), and the outer peripheral surface of the high pressure orbiting wrap (9) and the fixed wrap (6). A two-stage compression chamber including a low-pressure compression chamber (20) and a high-pressure compression chamber (21), each having a volume gradually decreasing toward the center, is formed between the inner peripheral surfaces of the. Each of these compression chambers (20) (21) has a fixed wrap
It is partitioned by a partition wall (22) provided in the middle of (6).

An air suction hole (23) is provided on the outer peripheral portion of the fixed scroll (2) so that the outside air having passed through a filter (not shown) is sucked into the low pressure compression chamber (20).

A discharge hole (24) communicating with the high pressure compression chamber (21) is formed in the center of the fixed end plate (4).
The (24) is connected to an air tank (not shown), an air tool or the like via a discharge pipe (25).

Further, on both sides of the fixed end plate (4) sandwiching the partition wall (22), the low pressure side discharge port (2) communicating with the low pressure compression chamber (20) is formed.
6) and a high-pressure side suction port (27) communicating with the high-pressure compression chamber (21) are provided.

As shown in FIG. 1, the low pressure side discharge port (26) is connected to the inlet side of the intercooler (29) via the conduit (28), and the high pressure side suction port (27) is , Is connected to the outlet side of the intercooler (29) via the conduit (30).

The fixed scroll (2) has a pressing plate on its front surface.
Fix the fixed scroll housing (11) to the front end opening of the drive shaft housing (12) with the tightening screw (33) while the (31) is fixed with the bolts (32). It is assembled together.

Cooling passage (A) in the swiveling roll (3)
The downstream low pressure swirl wrap (8) and the high pressure swirl wrap (9) on the right half centered on the discharge hole (24) formed in the central portion in FIG. The thickness (t) of the portion located near the center is different from that of other portions, especially the cooling passage.
It is slightly larger than the wall thickness (t ₀ ) of the left half which is the upstream side of (A).

As a result, the thin-walled low-voltage swirl wrap
(8) and high pressure swivel wrap (9) outer peripheral surface and fixed wrap
The radial gap between the inner peripheral surface (6) and the inner peripheral surface is slightly larger than the other portions (illustrated in an exaggerated manner).

This is because the temperature of the air passing through the cooling passage (A) becomes higher from the central portion toward the downstream side as described in the above-mentioned "Problems to be Solved by the Invention" This is to deal 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) located on the side.

That is, the low pressure swirl wrap (8) and the high pressure swirl wrap (8) having a large coefficient of thermal expansion and the fixed wrap.
If the gap between (6) is made large in advance by an amount corresponding to the coefficient of thermal expansion, the problem of contact between them can be solved.

The above-mentioned gap is, for example, 30 to 50 μm larger when the upstream gap is set to 40 to 50 μm in an ordinary compressor having high versatility, and 70 to 100 μm.
It is preferably in the range of m. If the thickness is less than 70 μm, the swirl wraps (8) and (9) may come into contact with the fixed wrap (6) without absorbing the thermal expansion.
This is because it has been confirmed by experiments that the clearance between the orbiting wraps (8) and (9) and the fixed wrap (6) becomes too large and the compression efficiency decreases when the value exceeds.

The compression temperature of air is highest near the discharge hole (24), which is the central part, and the temperature of the cooling air passing through that part is also high. Therefore, the swirling wraps (8) and (9) The wall thickness (t) is gradually thinned so as to become the minimum in the central portion of the cooling passage (A), and the fixed wrap (6) and the swivel wrap (8) (9)
It is preferable that the radial gap between them becomes larger toward the center of the cooling passage (A).

As in the above-described embodiment, the 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 large coefficient of thermal expansion is reduced over a required range. However, if the radial gap between the fixed wrap (6) and the regular lap is set to be slightly larger than the regular gap, both swirling wraps will be used even when the compressor is used especially under high ambient temperature conditions.
(8) There is no possibility that the fixed wrap (6) and the fixed wrap (6) will contact each other on the downstream side of the cooling passage (A).

Therefore, it is prevented that they wear and the gap becomes large, and the compression efficiency is deteriorated and the wrap is damaged.

The swivel wraps (8) and (9) and the fixed wrap
By preventing contact with (6), it is also possible to reduce the amount of cooling air blown by a cooling fan or the like, and it is possible to save the power consumption of the motor that drives it or use a small motor. And so on, economic effect can be obtained.

The present invention is not limited to the above embodiment. In the above-mentioned embodiment, the low pressure and high pressure swirl wraps (8) and (9) are made thin so that the gap between the swivel wraps (6) and the fixed wrap (6) is large. Decrease the thickness of the side, and swirl wrap (8) (9)
The radial gap between and may be set to be slightly large.

Further, in the above embodiment, the cooling passage
(A) is oriented in the left-right direction by opening ventilation openings (13) on the left and right side surfaces of the compressor casings (11), (12), and the cooling air flows from left to right in FIG. The cooling air is made to flow from the right to the left, or the ventilation port (13) is provided.
The direction of the cooling passage (A) may be changed by changing the position of the swirl wrap (8) (9) or the fixed wrap (6) located on the downstream side of the cooling air in any case. It may be thin and the gap between them may be large.

The present invention has a single-wrap, two-stage scroll type air compressor as described above, a single-wrap scroll (one-stage) type compressor, and orbiting wraps on both sides of the end plate of the orbiting scroll. It can also be applied to a double-wrap scroll (single-stage, multi-stage) compressor or the like.

[0037]

According to the present invention, the following effects can be obtained. (A) According to the invention described in claim 1, 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 possibility of contact between them. , Both wraps are prevented from being worn or damaged. Further, since it is also possible to reduce the air volume by the cooling fan or the like, it is possible to save the power consumption of the drive motor or the like and to downsize the motor, which is economical.

(B) According to the second aspect of the present invention, the thermal expansion of the fixed or swivel wrap can be effectively absorbed without lowering the compression efficiency.

(C) According to the third aspect of the invention, for example, even if the ambient 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 swirling wrap are provided with the cooling passage. Contact is prevented at the center of the.

[Brief description of drawings]

FIG. 1 is a central longitudinal side view of a main part showing an embodiment of the present invention.

FIG. 2 is likewise an enlarged vertical rear view of line II-II of FIG.

FIG. 3 is likewise an enlarged vertical rear view of line III-III in FIG. 1.

[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) Swivel wrap for low pressure (9) Swivel wrap for high pressure (10) Cooling fin (11) Fixed scroll housing (12) Drive shaft housing (13) Ventilation port (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) Partition wall (23) Suction hole (24) Discharge hole (25) Discharge pipe (26) Low pressure side discharge port (27) High pressure side inlet (28) conduit (29) Intercooler (30) conduit (31) Press plate (32) Bolt (33) Tightening screw (A) Cooling passage

Claims (3)

[Claims] 1. A fixed scroll fixed in a housing, having a suction hole and a discharge hole in an outer peripheral portion and a central portion, respectively, and having a spiral fixed wrap projecting from one side surface, and the fixed scroll. An orbiting scroll provided in the housing so as to be opposed to the housing and having a spiral orbiting wrap protruding from one side and fitted to the fixed wrap, and facing the housing. A ventilation port is provided, and a cooling passage formed between these ventilation ports is disposed on at least one of the other side surfaces of the fixed scroll and the orbiting scroll,
In the cooling passage, an air-cooled scroll type fluid machine configured to cool at least one of the fixed scroll and the orbiting scroll by circulating the cooling air sent from the one ventilation port, By making the thickness of the fixed wrap or the swirl wrap located on the downstream side of the discharge hole in the cooling passage slightly thin, the radial gap between the fixed wrap and the swirl wrap is made upstream of 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 orbiting wrap located on the side. 2. The air cooling according to claim 1, wherein the radial gap between the fixed wrap located on the downstream side and the swivel wrap is made larger by 30 to 50 μm than the gap between the fixed wrap located on the upstream side and the swivel lap. Type scroll type fluid machinery. 3. The air-cooled scroll type fluid according to claim 1, wherein the radial gap between the fixed wrap and the orbiting lap located on the downstream side is maximized near the center of the cooling passage. machine.