JPH0286979A - scroll compressor - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a scroll compressor used for refrigeration and air conditioning.

[Conventional technology]

In FIG. 3, it is used in a scroll compressor. In conventional scroll compressors.

Both scrolls are made of the same material, and the spiral teeth of both scrolls have the same shape. As shown in the cross-sectional view in Figure 4, one of them is rotated by 180 degrees, and the distance between the centers of the basic circles of the spiral teeth of both scrolls is P/2.
-t (P is the involute pitch, t is the tooth thickness), and theoretically there are four locations ((a), (b),
(c), (d) are in contact at l.

FIG. 5 is an explanatory diagram of the compression operation of the scroll compressor.

In FIG. 5, in synchronization with the left rotation of the crankshaft, the oscillating scroll (2) revolves in left rotation without rotating. It can be seen that the volume of the compression chamber in the shaded area decreases in the order of (a) → (b) → (c) → (d). At that time, each compression chamber is 2. For example, taking Fig. 4 as an example, (a) to (d)
It is divided by four contact points (contact points formed by the fixed scroll spiral tooth (1) and the oscillating scroll spiral tooth (2).Actually, it is a tangent line extending in the front and back directions of the page), and these contact points moves toward the center on an involute curve as the crankshaft rotates.

Based on the above principle, low-pressure gas taken in at the outer periphery is slowly compressed into high-pressure gas and guided to the central chamber.

[Problem to be solved by the invention]

In the past, iron-based materials were often used for both fixed scrolls and oscillating scrolls, but in recent years, as compressors have become faster, lightweight materials such as aluminum and resin are often used for oscillating scrolls. It is becoming. In other words, the materials used for fixed scrolls and orbiting scrolls are sometimes different. If the materials of the spiral teeth of both scrolls are different, if both scrolls with the same spiral shape at room temperature are operated, the difference in thermal expansion coefficient will be the main difference because both scrolls will be exposed to high temperature scum during operation and will become hot. As a result, the spiral tooth shapes of both scrolls are no longer the same. The situation is shown in FIG. FIG. 6 shows the shape of the spiral teeth of a cast iron fixed scroll, the shape of the spiral teeth of an aluminum oscillating scroll having the same shape, and their shape when the temperature increases. Therefore, when one combination is made, contact points are not formed at four locations as shown in Figure 4, and teeth interfere with each other at certain locations as shown in Figure 7. (a), (c) ) In other areas, large leaky gaps may occur between the teeth.

f(b), (d)1 This invention was made to reduce the "interference" and "leakage gap" during the above operation, and achieves high efficiency by suppressing mechanical loss due to interference and loss due to leakage. At the same time, it is an object of the present invention to provide a scroll compressor that reduces noise and vibration caused by interference and avoids deterioration in reliability caused by interference.

[Means to solve the problem]

A scroll compressor according to the present invention includes a fixed scroll and an oscillating scroll that have spiral teeth and are made of different materials, and the shape of the spiral teeth of the scroll having a larger coefficient of thermal expansion is smaller by a predetermined amount than the other scroll. It is something.

[Effect]

In the scroll compressor of this invention, since the shape of the spiral teeth of the scroll whose material has a larger coefficient of thermal expansion is relatively small, when both scrolls become hot during operation, the shape of the spiral teeth of the nine scrolls becomes close to the ideal (same shape), and interference and gaps between teeth are reduced.

〔Example〕

Two embodiments of the present invention will be described below with reference to FIGS. 1 and 2. This embodiment assumes that cast iron is used for the fixed scroll (1) and aluminum is used for the oscillating scroll (12). In Fig. 1, the spiral teeth (1) of the fixed scroll made of cast iron and the spiral teeth (I2) of the oscillating scroll made of aluminum are shown overlapped for convenience, with the center and phase of the upper scroll aligned. .

If a certain point on the inward surface of the spiral tooth (1) of a cast iron fixed scroll is (1a), then the distance L from the center of (la) is
Ia is expressed as L + a = 810,017 η7 (a is a constant, α is a constant, and φ is a certain real number).

On the other hand, if the point corresponding to (la) on the inward surface of the spiral tooth (12) of the aluminum oscillating scroll is (12a), then the distance from the center of (12a) is L11! a is L
+ 2a"" a + 2, η] quantity ")' (a
12 is a constant). here.

a,,<a.

Therefore, the spiral teeth (12) of the aluminum oscillating scroll are the same as the spiral teeth (12) of the cast iron fixed scroll.
), it has a relatively small shape.

Now, the fixed scroll and oscillating scroll during operation are as follows:
It becomes high temperature because it is exposed to high temperature and high pressure gas. When the temperature rises, the nine scrolls expand thermally almost in proportion to their temperature rise and coefficient of thermal expansion. Figure 2 shows the spiral teeth (12
b) and the spiral teeth (2b) of the cast iron oscillating scroll used in pair therewith when the temperature rises are shown with the centers and phases of both scrolls aligned. In addition, those at room temperature are also shown.

As is clear from comparing Figure 2 with Figure 6.

When the temperature rises, the spiral teeth (12b) of the aluminum oscillating scroll according to the second embodiment have almost the same shape as the spiral teeth (2b) of the cast iron oscillating scroll. Even though it is a scroll, during operation, that is, when the temperature rises, differences in the spiral shape that cause tooth interference and tooth leakage gaps are largely corrected. According to the present invention, a fixed scroll and an oscillating scroll having spiral teeth and made of different materials are provided, and the shape of the spiral tooth of the scroll having a larger coefficient of thermal expansion is made smaller by a predetermined amount than that of the other scroll.

Teeth interference and leakage gaps are reduced, and as a result, a scroll compressor with high efficiency, low noise and vibration, and high reliability can be obtained.

[Brief explanation of drawings]

Figure 1 shows the shape of the spiral teeth of an aluminum oscillating scroll according to an embodiment of the present invention, and the shape of the spiral teeth of a fixed cast iron scroll used in a pair. FIG. 2 is an explanatory diagram of the same two operations, FIG. 3 is a perspective view of essential parts of a scroll compressor, and FIGS. 4 and 7 are explanatory diagrams of a conventional scroll compressor. In the figure, (1) and (12) are spiral teeth, U, =)
is a fixed scroll, and (1,) is an oscillating scroll. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A scroll compressor comprising a fixed scroll and an oscillating scroll having spiral teeth and made of different materials, wherein the shape of the spiral tooth of the scroll having a larger coefficient of thermal expansion is made smaller by a predetermined amount than that of the other scroll.