JPS63205482A - Discharge bypass valve for scroll compressor - Google Patents

Abstract

PURPOSE:To maintain high efficiency under extensive pressure ratio conditions, by installing a bypass port, letting over compression escape to the discharge side, at the center of groove between laps, and also installing a check valve in this bypass port. CONSTITUTION:In this scroll compressor, a compressor part 1 and an electric motor part 2 are housed in a hermetically sealed vessel 3. A compression space of this compressor part 1 is made up of having a fixed scroll member 5 and a turning scroll member 7 engaged with each other. In a fixed scroll end plate 5a, there is provided with a bypass port 21, interconnecting the compression space to a discharge space 3a, at the groove center. In this bypass port 21, there is provided with a check valve 22, leading to only the direction of the discharge space 3a or the inside of a discharge pipeline from the compression space. Thus, high efficiency is maintainable under extensive pressure ratio conditions.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a refrigeration and air conditioning system using a scroll compressor, and particularly to a structure suitable for a scroll compressor that controls capacity by controlling the rotation speed.

[Conventional technology]

The conventional device described in JP-A-57-137677, Positive Displacement Scroll Type Gas Compressor, was designed to reduce the torque generated at startup, and the position of the hole in the bus valve was not specified. I haven't.

Furthermore, the scroll compressor of JP-A-58-128485 also shows a structure in which compressed gas is bypassed when the pressure in the compression space becomes higher than the discharge pressure, but the position of the hole in the bypass valve is not specified. do not have.

[Problem that the invention seeks to solve]

゛ The above prior art does not address the location of the bypass holes and is not necessarily designed to optimize efficiency. The present invention focuses on the fact that the pressure ratio during operation is most often in the range of 0.5 to 0.75 of the set pressure ratio in a refrigeration air conditioner that controls capacity by changing the rotation speed of an inlet. By operating the bypass valve at this pressure ratio, the energy saving effect can be maximized.

[Means to solve all problems]

The above purpose is achieved by providing a bypass hole in the center of the groove between the wraps and installing a check valve to release overcompression pressure to the discharge side.
Pressure ratio 0.5 to 1 for the most common set pressure ratio during operation
．． In the range of 0, many efficiency-enhancing effects are obtained and achieved.

[Effect]

The discharge bypass valve has a bypass hole provided in the end plate at the center of the groove between laps and a reverse valve that communicates only from the compression chamber to the discharge chamber or the discharge piping. When the pressure becomes higher than the internal pressure, the check valve operates to open the passage, and the working fluid in the compression chamber flows out from the bypass hole into the discharge chamber or the discharge pipe before reaching the discharge hole provided in the center of the wrap. However, when the pressure in the compression chamber becomes lower than the pressure in the discharge chamber or the discharge pipe, the check valve, which had been open, closes and closes the passage in the discharge bypass valve. As mentioned above, the check valve uses an automatic valve that is operated by a pressure difference acting before and after the cell.

Furthermore, by providing two bypass holes at the center of the inter-wrap groove, facing each other at 180 degrees, the two bypass holes open into the compression chamber in sequence during the process from the start of compression to the completion of discharge. Therefore, the bypass hole can be left open for a longer period of time than when the bypass hole is provided in the wrap side wall, and this has the effect of reducing overcompression pressure over a wide pressure ratio range.

〔Example〕

゛゛Hereinafter, one embodiment of the present invention will be explained with reference to FIGS. 1 to 3.

The scroll compressor shown in FIG. 1 includes a compressor section 1 and a motor section 2 housed in a closed container 3. The scroll compressor shown in FIG. In the compressor section 1, a fixed scroll member 5 and an orbiting scroll member 6 are engaged with each other to form a compression chamber (sealed space). The fixed scroll member 5 consists of a disc-shaped end plate 5a and a wrap 5b standing upright on the end plate and formed in an impolied curve or a curve similar to this. A suction port 11 is provided. The orbiting scroll member 6 is composed of a disk-shaped end plate 6a, a wrap 6b standing upright thereon and formed in the same shape as the wrap of the fixed scroll, and a boss 6C formed on the opposite surface of the end plate. The frame 7 has a bearing part 7a formed in the center, and the rotating shaft 4 is supported by this bearing part, and the eccentric shaft 4aV-1 at the tip of the rotating shaft, the boss 6C mentioned above.
It is inserted in such a way that it can be rotated. Further, in the frame 71C, the fixed scroll member 5 is fixed by a plurality of bolts, and is supported on the frame 7 by an Oldham machine 9 consisting of an Oldham ring and an Oldham key with six orbiting scroll members, and the orbiting scroll member 6 is fixed to the fixed scroll member 5. On the other hand, it is formed so that it can rotate without rotating. The rotating shaft 4 has an electric motor section 2 at the bottom.
are directly connected. A suction pipe a is connected to the suction port 11 of the fixed scroll member 5 through the closed container 3, and a discharge chamber 3ail':1' passage (14
It communicates with the lower chamber 3b via a), and further communicates with a discharge pipe 32 that penetrates the closed container 3.

On the other hand, a space 8 (this is called a "back pressure chamber") surrounded by the back surface of the orbiting scroll member 6 and the frame 7,
Suction pressure is applied to counter the gas force in the thrust direction due to the gas pressure in the plurality of sealed spaces formed by both fixed scrolls (this force becomes a separation force that tries to push down the orbiting scroll member 6). (low pressure side pressure) and the pressure between the discharge pressure acts. This intermediate pressure is set by providing a pore 16 in the end plate 6a of the orbiting scroll 6.
The gas inside the scroll is introduced into the back pressure chamber 8 through the scroll, and the gas is applied to the back surface of the orbiting scroll.

,So,.

- The rotating shaft 4 and the eccentric shaft 4a are provided with oil supply holes 4C for supplying oil to each bearing part from the lower end of the rotating shaft 4 to the upper end surface of the eccentric shaft 4a, and the lower end 4d of the rotating shaft is located at the bottom of the closed container 3. immersed in lubricating oil.

In addition, a balance weight is formed in the lower part of the eccentric shaft part 4a to be engaged with and integrated with the rotating shaft at the upper part of the main bearing which is opposed to the tip end surface of the orbiting scroll boss part 6C.

As shown in Figures 2 and 3 of the imperial edict, the fixed scroll end plate 5
A has a bypass hole 2 that communicates the compression chamber and the discharge chamber 3a.
1 is provided in the center of the groove, and a discharge bypass valve 25 comprising a reed valve 22 for closing the bypass hole 21, a retainer 23, and a bolt 24 is mounted.

Next, the mounting position of the bypass hole will be specifically explained. The center coordinates (x, y) of the bypass hole are expressed by the following equation using the basic circle radius a of the spiral line, the wrap thickness t1, the turning radius ε, and the winding angle λ.

x = a (House λ + (λ + and Sn) smλ) a ε + t y = a (Kun λ - (λ + ) Ning λ) This means that the beginning of winding of the spiral outer line, which is the formula for the spiral line at the center of the groove between laps, is λ, Let the end of the winding be λ.

If the winding end of the extension wire is λ8+π in the case of FIG.

The compression chamber is formed separately with inner and outer spiral lines, and moves to the center as the crankshaft rotates. Therefore, in order to obtain the same effect as each compression chamber, two or more are required at positions 180 degrees opposite to each other. In the case of Figure 2, there are two. The winding position of the bypass hole near the beginning of winding is λ
It is preferably between 5 and λ, +2π. Furthermore, it is preferable that the thickness of the bypass hole be approximately equal to the thickness of the wrap.

The characteristics of the discharge bypass valve 25 configured as described above are described in the fourth section.
This will be explained using Figure 5. While the compression chamber moves from the start of compression to the completion of discharge as the crankshaft rotates, that is, while the compression chamber moves from the outside toward the center, the outer bypass hole (the one with the larger winding angle position) is first opened. One end opens into the compression chamber. At this time, if the pressure in the compression chamber is greater than the pressure in the discharge chamber, the valve is pushed up, the bypass hole communicates with the discharge chamber, and the compressed gas flows out from the compression chamber to the discharge chamber. When the crankshaft further rotates, the bypass hole no longer communicates with the compression chamber, but instead, one end of the inner bypass hole (the one with the smaller winding angle position) opens into the compression chamber. In this way, since the two bypass holes open sequentially, the compression chamber can communicate with the bypass holes over a wide range.

Therefore, low efficiency can be maintained over a wide range of pressure ratios as shown in FIG.

On the other hand, the conventional technique in which the bypass hole is provided near the side wall of the lap is shown by the dotted line, but only one bypass hole can be effectively used for the compression chamber, and the efficiency decreases when the pressure ratio becomes low. descend.

〔Effect of the invention〕

According to the present invention, since the bypass hole can be communicated over a long section while the compression chamber moves from the start of compression to the completion of discharge, high efficiency can be maintained under a wide range of pressure ratio conditions even under conditions lower than the design pressure ratio. There is an effect that can be done.

[Brief explanation of the drawing]

Fig. 1 is a vertical sectional view of a scroll compressor showing an embodiment of the present invention, Fig. 2 is a bottom view of the fixed scroll in Fig. 1, Fig. 3 is an enlarged sectional view of the bypass valve portion, and Fig. 4 is Diagram showing the relationship between crank rotation angle and bypass hole opening area, 5th
The figure is a diagram showing the relationship between bypass hole position and efficiency. 5... First scroll member 6... Second scroll member 13... Discharge hole 21... Bypass hole 22... Check valve.

Claims (1)

[Claims] 1. A first scroll member and a second scroll member each having a spiral wrap standing upright on an end plate are provided, the pair of scroll members are assembled with each other with the wraps inside, and the first scroll member is On the other hand, in a device that compresses gas by rotating the second scroll member so that it does not rotate relative to its axis, the compression space and the discharge chamber or the inside of the discharge piping before communicating with the discharge hole provided in the center of the first scroll member are One or several bypass holes are provided in the end plate at the center of the inter-lap groove, and a check valve is provided in each bypass hole to communicate only from the compression chamber to the discharge chamber or the inside of the discharge pipe. scroll compressor. 2. The wraps of the first scroll member and the second scroll member have a symmetrical wrap shape with the same wrap length,
A plurality of pairs of bypass holes are provided in the center end plate of the inter-lap groove facing each other at 180°, and a check valve is provided in each bypass hole. scroll compressor. 3. It is an asymmetrical wrap shape in which the first scroll member and the second scroll member have different wrap lengths, and the two symmetrical compression chambers have the same compression start position. A scroll compressor according to claim 1, wherein a stop valve is provided at one location. 4. The wrap thickness of the scroll member is t, the turning radius is Σ,
When the basic circle radius of the spiral line is a and the winding angle is λ, the center position of the bypass hole is expressed by the following x and y coordinates, x=a[cosλ+{λ+(2Σ+t)/2a}sin
λ]y=a[sinλ−{λ+(2Σ+t)/2a}c
osλ] The range of the winding angle λ is from the winding starting angle λ_1 to λ_
Scroll compressor according to claim 1, wherein 1+2π.