JPS59176483A - Scroll fluid machine - Google Patents

Abstract

PURPOSE:To prevent the contact of scroll plates due to thermal expansion and improve the reliability by constituting a scroll fluid machine so that the height of at least one scroll side plate is made lower at the inner side than at the peripheral side. CONSTITUTION:(a) is a stationary scroll 1, and is molded so that the height of a scroll side plate 1a is made continuously lower toward the inner side from the peripheral side. (b) is a swayable scroll 2, and the height of a scroll side plate 2a is made continuously lower toward the inner side from the peripheral side in the same way as shown for the stationary scroll 1. That is, when the operating fluid is compressed, a temperature gradient is generated between the scroll side plates 1a, 2a and bottom plates 1b, 2b with the inner side temperature being higher, but the height of the scroll side plates 1a, 2a is made lower at the inner side in advance, thereby the height becomes almost equal at both sides after the deformation due to thermal expansion.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a compression section of a scroll fluid machine such as a scroll compressor.

Before entering into the description of this invention, the principle of a scroll compressor will be described.

The basic elements of a scroll compressor are shown in Figure 1 (,1~(di
In Fig. 1, 1 is a fixed scroll, 2 is an oscillating scroll, 3 is a discharge port, 4 is a compression chamber,
0 is a fixed point on the fixed scroll 1, and 0/ is a fixed point on the swinging scroll 2.

The fixed scroll 1 and the swinging scroll 2 are composed of spirals having the same shape, and the shape is a combination of an involute or a circular arc, as is conventionally known.

Next, the operation will be explained. The fixed scroll 1 is stationary with respect to space, and the swinging scroll 2 is combined with the fixed scroll 1 as shown in the figure, and performs rotational movement, that is, swinging, without changing its attitude relative to space. Figure 1 (-), (b).

O', 90°, 180°, 2 shown in (c) and (d)
Move like 70°. As the swinging scroll 2 moves, the crescent-shaped compression chamber 4 formed between the fixed scroll 1 and the swinging scroll 2 gradually reduces its volume.
The gas that is suitable for the compression chamber 4 is compressed and discharged from the discharge port 3. During this time, the distance o-o' in FIG. 1 is kept constant, and if the interval between the spirals is a and the thickness is t, then oo'=3-4. a corresponds to the pitch of the spiral.

The outline of the device known as a scroll compressor is as above.

Next, the configuration and operation of a specific embodiment of the scroll compressor will be described.

FIG. 2 shows an example of a conventional scroll compressor.

In FIG. 2, reference numeral 1 denotes a fixed scroll, including a scroll side plate 1a having an involute shape, a bottom plate 1b supporting the scroll side plate 1a, and a discharge port 3.
．． It is constituted by an inlet 5. 2 is a scroll side plate 211 which is an oscillating scroll and has the same shape as the fixed side but has the opposite winding direction. It is composed of a bottom plate 2b and a boss 11 that support the scroll side plate 2a. 4 is a fixed scroll side plate 1&, a bottom plate 1b, and an oscillating scroll side plate 2.
a, a compression chamber formed by the bottom plate 2NC, 3 a discharge port,
4 is a compression chamber, 5 is a suction port, 6 is a bearing support, 7 is a thrust bearing, 8 is a crankshaft having an eccentric hole 12, 9 is an anti-rotation device that prevents the orbiting scroll 2 from rotating, and 10 is a balancer. . The above are the main components. The orbiting scroll 2 is fitted with the fixed scroll 1 and the scroll side plates 1a and 2a facing each other, and the boss portion 11 of the orbiting scroll 2 is connected to the eccentric hole 14 of the crankshaft 8.

The crankshaft 8 is fitted into the bearing support 6, and the bearing support 6 and the fixed scroll 1 are connected with bolts or the like (not shown). Further, the thrust bearing 7 formed on the bearing support 6 and the surface of the bottom plate 2b of the swinging scroll 2 opposite to the side where the scroll side plate 2a is formed are assembled so as to be in contact with each other.

Further, a balancer 10 is fixed to the crankshaft 8 by being press-fitted or screwed.

Next, the operation of this scroll compressor will be described. Rotational torque transmitted from a drive unit (not shown) such as an electric motor rotates the crankshaft 8. Then, the oscillating scroll 2 starts to rotate via the boss portion 11 of the oscillating scroll 2, but since the rotation is prevented by the rotation prevention device 9, the fixed scroll 1 and the oscillating scroll 2 are rotated as shown in FIG. According to the compression principle, the working fluid is compressed. Here, the oscillating scroll 2 performs an eccentric revolution movement, and its static and dynamic balance is performed by a balancer 10.

In the scroll compressor described above, the temperature of the working fluid increases during the compression process from the suction port 5 to the discharge port 3. If this compression process is adiabatic compression, the temperature rise ΔT of the working fluid from the inlet 5 to the outlet 3 is expressed as ΔT-TS ((pa/pg) kl).

Here, T8 is the temperature of the working fluid at the suction port, Ps is the pressure at the suction port, Pd is the pressure at the discharge port, and k is the adiabatic index. Such temperature rise of the working fluid causes the scroll side plates 1 of the fixed scroll 1 and the oscillating scroll 2 to
a, 2a and bottom plate 1b.

2b, the temperature is lowest at the outer circumferential side where the suction port 5 is located, and the temperature is higher toward the center where the discharge port 3 is located, 1/Cfx.

Therefore, the fixed scroll 1 and the oscillating scroll 2 are forced to deform due to thermal expansion, respectively.
As shown by broken lines in bl, the scroll side plates la and 2a become more convex toward the center. Figure 3 (,) shows the defined scroll, and (b) shows the oscillating scroll, and the solid lines in these figures indicate the state when not in operation, that is, there is no temperature gradient in the fixed scroll 1 and the oscillating scroll 2. Indicates the state at the time. Fixed scroll 1 during such operation
The deformation due to thermal expansion of the oscillating scroll 2 occurs at the tips of the scroll side plates 1a and 2a and the bottom plate 2b.

1b, resulting in increased mechanical loss and damage to the compressor such as seizure.

This invention attempts to eliminate the above-mentioned drawbacks of the conventional scrolls, and the height of the scroll side plate of at least one of the fixed scroll and the oscillating scroll is set so that the height of the scroll side plate is lower on the outer circumferential side than on the inner circumferential side. The purpose of this invention is to prevent a scroll side plate from coming into contact with a mating scroll bottom plate due to thermal expansion, thereby providing a highly reliable scroll fluid machine such as a scroll compressor.

An embodiment of the present invention will be described below with reference to FIGS.
I will explain about it.

FIG. 4(-) shows a fixed scroll 1 in which the height of the scroll side plate 1a is continuously lowered from the outer circumferential side toward the inner circumferential side. In addition, in FIG. 4(a), the height is lowered linearly from the outer circumference toward the inner circumference, but it may be curved. The difference in height between the outer and inner scroll side plates 1a is set in consideration of the aforementioned thermal expansion and the deflection of the bottom plate 1b due to the working fluid pressure. FIG. 4(b) shows an oscillating scroll 2, which is also similar to the fixed scroll 1 shown in FIG. It is low and low.

With such a structure, when the scroll compressor is operated and the working fluid is compressed, the scroll side plates 1a and 2 of the fixed scroll 1 and the oscillating scroll 2 are compressed as the working fluid is compressed.
a and the bottom plate 1b.

2b, a temperature gradient occurs, and the temperature on the inner circumferential side is higher than on the outer circumferential side, but since the height of the scroll side plates 1g and 2a is set lower on the inner circumferential side than on the outer circumferential side, The heights after deformation due to thermal expansion are approximately equal. Therefore,
The surfaces formed by the tips of the scroll side plates 1a, 2a are uniformly flat without any convex portions, and contact with the bottom plates 2b, 'lb can be avoided.

Note that the unevenness of the plane created by the tips of these scroll side plates during operation is determined by the above-mentioned amount of thermal expansion and the deflection of the bottom plate due to gas pressure. If the above-mentioned structure has the larger unevenness, contact between the tip of the scroll side plate and the bottom plate can be avoided.

FIG. 5 shows another embodiment of the present invention, in which (,) indicates a fixed scroll 1 and (b) indicates an oscillating scroll 2. The fixed scroll 1 shown in FIG. The tip of the scroll side plate 1a near the outlet 3 is cut over a certain range so that it is lower than the height of the outer circumferential side. This difference in height takes into consideration the thermal expansion described above and the deflection of the bottom plate 1b due to the working fluid pressure. With this structure, it is possible to avoid contact between the tip of the scroll side plate 1a near the discharge port 3 where thermal expansion is maximum and the bottom plate 2b of the oscillating scroll 2. The cutting range is determined by the difference in thermal expansion of the scroll side plate 1m due to the temperature distribution that occurs during operation of the fixed scroll 1, and the area where the tip of the scroll side plate 1a and the bottom plate 2b of the oscillating scroll 2 come in contact with each other based on the gap set during assembly. You should try to avoid it.

Fig. 5 (bl is the swinging scroll 2; Fig. 5 (a)
This is similar to the fixed scroll 1 of No. 1, and the height of the scroll side plate 2a on the inner circumference side is cut within a certain range so that it is lower than the height on the outer circumference side.

With such a structure, the same effect as in the embodiment shown above can be obtained, and the temperature on the inner circumferential side of the fixed scroll l and the oscillating Shumir 2 is not higher than the temperature on the outer circumference 911j by p during operation. Even if the amount of thermal expansion of the scroll side plates 1a and 2a on the inner circumference side becomes larger than that on the outer circumference side, the scroll IJt
Contact between the tips of the plates ia and 2a and the bottom plates 2b and lb can be avoided.

Note that configurations other than those described above in both of the above embodiments.

Since the operation is similar to the conventional one shown in FIG. 2, the explanation will be omitted.

Further, the present invention is widely applicable not only to compressors such as refrigerant compressors and air compressors, but also to scroll fluid machines such as fluid bongs, turbine expanders, and superchargers.

As explained above, the present invention has the advantage that the height of the scroll side plate of at least one of the fixed scroll and the oscillating scroll is made lower on the inner circumferential side than on the outer circumferential side, so that even if the scroll side plate thermally expands during operation, Since the tips of the scroll side plates form a nearly uniform horizontal surface, they do not come into contact with the bottom plate (which eliminates problems such as increased mechanical loss and seizure caused by conventional contact between the scroll side plates and the bottom plate, and improves reliability. This has the advantage that it is possible to provide a scroll fluid machine with high performance.

[Brief explanation of the drawing]

Figures 1F, 1, (b), (c), and (d) are diagrams of the operating principle of a scroll compressor shown in the order of operation, Figure 2 is a longitudinal sectional view of a conventional scroll compressor, and Figure 3 (, )
, (b) is a vertical cross-sectional view showing thermal deformation of a fixed scroll compressor and an oscillating scroll, respectively, and FIG.
). (b) is a longitudinal sectional view showing a fixed scroll and an oscillating scroll according to an embodiment of the present invention, and FIG. 5 is a longitudinal sectional view showing a fixed scroll and an oscillating scroll according to another embodiment of the invention. 1...Fixed scroll, 1a...Scroll side plate,
1b...bottom plate, 2...oscillating scroll, 2a...
Scroll side plate, 2b...bottom plate, 3...discharge port, 5
...Inhalation port. Note that the same reference numerals in the figures indicate the same or corresponding parts. Agent Shin Kuzuno - (1 other person) 71r! lJ O 2 @? a Figure (a-)

Claims (1)

[Claims] In a scroll fluid machine such as a scroll compressor that combines a fixed scroll and an oscillating scroll having a pair of spirals having the same shape and opposite winding directions, such as an involute, at least one of the fixed scroll and the oscillating scroll. A scroll fluid machine characterized in that the height of the side plate is lower on the inner circumferential side than on the outer circumferential side.