JP2577125Y2 - Scroll compressor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a scroll compressor, and more particularly, to a scroll compressor provided with a load reduction device at the time of starting.

(Prior Art) Conventionally, this kind of scroll compressor is disclosed in
It was configured as disclosed in Japanese Patent No. 62093.
That is, as shown in FIG. 3, the scroll compressor disclosed in the above-mentioned publication discloses an orbiting scroll 1 in which a spiral wall 1b is formed upright on a base plate 1a and a spiral wall 2b upright on a base plate 2a. The fixed scroll 2 thus formed is combined with the spiral walls 1b and 2b so as to mesh with each other, and the orbiting scroll 1 is sandwiched between the fixed scroll 2 and the frame 3. On the back surface of the base plate 1a of the orbiting scroll 1, an orbiting bearing 1c is formed and a rotation preventing mechanism (not shown) is provided. A drive shaft (not shown) is connected to the swing bearing 1c.

A suction pipe 2c is connected to the base plate 2a of the fixed scroll 2 and communicates with a compression chamber formed between the base plates of the scrolls. A discharge hole 2d is formed at a substantially central portion of the base plate 2a. I have. Various components such as the orbiting scroll 1, the fixed scroll 2 and the frame 3 are arranged in a casing 4, and an upper portion communicating with the compression chamber through a discharge hole 2d is provided between the upper portion of the fixed scroll 2 and the casing 4. A space 4a is formed, and the upper space 4a is normally maintained at a discharge pressure. The casing 4 is provided with a discharge pipe 5 communicating with the upper space 4a.

In such a scroll compressor, if the oscillating scroll 1 is caused to oscillate (revolve) without rotating, the base plates 1a and 2a of the oscillating scroll 1 and the fixed scroll 2 and the spiral wall 1b as already known. , 2b, the volume thereof is reduced as it moves toward the center of the scroll, and the fluid sucked from the suction pipe 2c is compressed and discharged to the upper space from the discharge hole 2d.

When the scroll compressor as described above is used for an air conditioner or a refrigerator, a phenomenon called "stagnation" occurs in which the refrigerant is condensed in the compression chamber C during stoppage, and the air conditioner or the refrigerator is started in this state. And the liquid compression occurs, causing the bearing to become in a constrained state or the seizure of the bearing due to abnormal pressure rise in the compression chamber C or the spiral wall 1
There were problems such as breakage of b and 2b. In order to reduce the pressure in the compression chamber due to the liquid compression, in the conventional scroll compressor, a relief port 7 is formed on the base plate 2a of the fixed scroll 2 as shown in FIG. When a pressure higher than the pressure generated in the compression chamber C during normal operation acts on the relief valve 7a, the relief valve 7a is opened to release the pressure into the upper space 4a of the casing 4. That is, during normal operation, since the relief valve 7a is closed, the fluid in the compression chamber C is compressed as the compression chamber C moves toward the center, and is discharged from the discharge hole 2d. However, when the pressure in the compression chamber C rises abnormally during liquid compression or the like and becomes higher than the relief valve operation set pressure, the relief valve 7a opens, and the abnormally risen pressure is released to the upper space 4a.
The pressure is reduced to escape.

(Problems to be Solved by the Invention) However, in the conventional scroll compressor having such a relief means, a sufficient depressurizing effect cannot be obtained depending on the installation position of the relief means, and the above-described problem occurs. was there.

The purpose of the present invention is to solve such a conventional problem. An abnormal increase in the pressure in the compression chamber, which occurs during a so-called slewing start, is reliably released to the high pressure side, and the pressure in the compression chamber that has abnormally increased is most effective. An object of the present invention is to provide a scroll compressor that can reduce the size of the scroll compressor.

(Means for Solving the Problems) The scroll compressor according to the present invention combines a fixed scroll and an orbiting scroll each having a spiral wall formed on a base plate, and turns the orbiting scroll to rotate the orbiting scroll. In a scroll compressor, a compression chamber surrounded by a base plate and the spiral wall is moved to the center of the scrolls to reduce the volume of the compression chamber and communicate with a discharge hole provided at the center of the fixed scroll. A relief means for allowing the compressed fluid in the compression chamber to escape to a discharge space on the base plate of the fixed scroll, wherein the relief means comprises:
Compression of the middle part except for a pair of symmetrical compression chambers that are in communication with the discharge hole for the first time in the radially innermost part and a pair of symmetrical compression chambers formed by a spiral wall formed by 360 ° from the radially outer end. Among the chambers, a pair of outer symmetrical compression chambers respectively adjacent to the radially innermost compression chamber that communicates with the discharge hole for the first time, and the fixed scroll table on the side closest to the radially innermost compression chamber. It is formed of a pair of symmetric holes provided in the plate and a valve provided when the pressure is higher than a set pressure provided in the pair of holes.

(Operation) According to the scroll compressor of the present invention, the relief means does not operate during normal compression (gas compression), and the fluid taken into the compression chamber is compressed and discharged from the discharge hole as high-pressure fluid. However, when liquid enters the compression chamber and causes liquid compression, the pressure in the compression chamber abnormally increases. In this case, the compression chamber is in a state of being applied to the relief port. Therefore, when the pressure of the compression chamber becomes higher than the preset operating pressure of the relief means, the relief valve opens, and the high-pressure fluid passes through the relief port to the external space. leak.

(Embodiment) Hereinafter, the scroll compressor of the present invention will be described in more detail with reference to the embodiment shown in the accompanying drawings.

FIGS. 1 (a) to 1 (d) are principle explanatory diagrams showing a compression operation in a scroll compressor according to an embodiment of the present invention. 1 (a) to 1 (d), reference numeral 1 denotes an orbiting scroll, 2 denotes a fixed scroll, 2d denotes a discharge hole provided in the fixed scroll 2, and 10 denotes a relief means provided in the fixed scroll 2. A pair of relief ports,
C indicates a compression chamber formed between the scrolls 1 and 2 respectively.

Oscillating scroll 1 and fixed scroll 2 are
A spiral wall 1b, 2b having the same shape is provided on one surface of a, 2a, and the form of the spiral wall 1b, 2b is a combination of an involute or an arc as well known. The fixed scroll 2 is stationary with respect to the space, and the oscillating scroll 1 is combined with the fixed scroll 2 as shown in the figure to perform a rotation motion that does not change its attitude with respect to the space, that is, a predetermined oscillating radius. 0 (a) in FIG. 1 (a), 90 ° in FIG. 1 (b), 180 ° in FIG. 1 (c), and 2 in FIG. 1 (d).
Exercise like 70 °. With the movement of the orbiting scroll 1, the crescent-shaped compression chamber C formed between the fixed scroll 2 and the orbiting scroll 1 sequentially reduces its volume, and the gas taken into the compression chamber C is compressed. It is discharged from the discharge hole 2d.

A pair of relief ports 10 constituting the relief means,
The radially innermost compression chamber C ₁ (FIG. 1 (b)) communicating with the discharge hole 2d and the compression chamber C ₃ formed by the spiral walls 1b and 2b at an angle of 360 ° from the radially outer end. provided in the first diagram (a)) the base plate 2a at a position which communicates with compression chamber C ₂ of the intermediate portion discharge space or the upper space section 4a (FIG. 3) except for these ports 10 at a predetermined pressure It is closed by an open relief valve (not shown).

According to such a scroll compressor, FIG. 1 (a)
1 (d), as the rotation angle of the orbiting scroll 1 advances to 0 °, 90 ° and 180 °, the volume of the orbiting scroll 1 decreases, and the pressure in the compression chamber increases. . In normal compression (gas compression), the relief means does not operate as described in the conventional example, and the fluid taken into the compression chamber C is compressed and discharged from the discharge hole 2d as a high-pressure fluid. But,
When the liquid enters the compression chamber C and causes liquid compression, the pressure in the compression chamber abnormally increases. In this case, the pressure in the compression chamber C is applied to the relief port 10. Therefore, when the pressure in the compression chamber becomes higher than the preset operating pressure of the relief means, the relief valve opens, and high-pressure fluid passes through the relief port 10. Outflow to the outside space.

FIG. 2 shows the relationship between the installation position of the relief means, the pressure in the compression chamber, and the restraint time. The horizontal axis indicates the position where the relief means is provided (the rotation angle, the rotation angle at the start of compression is the origin), and the vertical axis. The axis represents a test value which is a product (hereinafter, referred to as PT) of a pressure in the compression chamber at the time of start of sleep at each rotation angle and a measured value of the restraint time at that time. The greater the PT, the greater the pressure in the compression chamber and the longer the constraint time. Θ ^* is a rotation angle at which the compression chamber communicates with the discharge time. As shown in FIG. 2, the reduction effect of PT increases as the rotation angle increases, that is, as the relief means is placed closer to the center. Therefore, as shown in FIG. 1, the radially innermost compression chamber C ₁ (FIG. 1 (b)), which communicates with the discharge hole 2d, and the compression chamber formed by a spiral wall at an angle of 360 ° from the radially outer end. If the relief means is installed at a position communicating with the compression chamber in the middle part except for C ₃ (FIG. 1 (a)), the abnormal rising pressure and the restraining time in the compression chamber can be reduced more effectively. That is, it is possible to minimize the load at the time of starting.

In the above-described embodiment, the radially innermost compression chamber that communicates with the discharge hole and the compression chamber formed by a spiral wall formed at an angle of 360 ° from the radially outer end are the most intermediate positions. Although the case where the relief means is provided at a position close to the discharge space is shown, the relief means is connected to the radially innermost compression chamber C ₁ (FIG. 1 (b)) and the radially outer end which communicate with the discharge hole 2d.
Except for the compression chamber C ₃ (FIG. 1 (a)) formed by a spiral wall of 360 °, that is, if it is installed at a position that does not communicate with these compression chambers, abnormal pressure in the compression chamber during liquid compression or the like will occur. Needless to say, the rise and restraint time can be effectively reduced.

Although FIG. 1 does not show the state of the innermost compression chamber in the radial direction that just communicates with the discharge hole for the first time,
Looking at the movement of the four figures showing the compression process for each °, (c)
It can be seen that the compression chamber is generated during the transition from (d) to (d).

In (d), assuming that the inner compression chamber adjacent to the hatched compression chamber C2 has just communicated with the discharge port for the first time, the outer diagonal compression chamber C2 is the radially innermost part that communicates with the discharge hole for the first time. It can be seen that the relief port 10 is provided on the fixed scroll base plate on the side closest to the innermost compression chamber in the radial direction, substantially corresponding to the outer compression chamber adjacent to the first compression chamber. The compression chamber provided with the relief port 10 follows the compression process in the order of (d), (a), (b), and (c), and determines the position of the relief port 10 in the corresponding compression chamber. (D) from the time of forming the outer compression chamber adjacent to the innermost compression chamber in the radial direction for the first time communicating with the discharge hole, the minimum immediately before communicating with the discharge hole as shown in (c). It continues to communicate with the relief port until the volume is reached, indicating that it always communicates with the relief port at the time of maximum compression such as liquid compression.

(Effects of the Invention) As described above, according to the scroll compressor of the present invention, the discharge hole in the middle compression chamber that does not communicate with the low-pressure side and does not communicate with the high-pressure space. By providing a relief hole in the fixed scroll base plate closest to the radially innermost compression chamber in the outermost compression chamber adjacent to the radially innermost compression chamber that first communicates with the Communicates with the relief hole from the time of formation of the outer compression chamber adjacent to the innermost compression chamber in the radial direction that communicates with the hole for the first time until it reaches the minimum volume immediately before communication with the discharge hole. It will be in communication with the hole, and there is no recompression, even if liquid compression occurs,
Abnormal pressure increase can be reliably prevented.

[Brief description of the drawings]

1 (a) to 1 (d) are explanatory views showing the principle of a compression operation in a scroll compressor according to an embodiment of the present invention.
FIG. 2 is a characteristic diagram showing the relationship between the product of the abnormally rising pressure and the restraint time in the scroll compressor and the position of the relief means installed, and FIG. 3 is a cross-sectional view showing a compression mechanism in the conventional scroll compressor. 1 ... oscillating scroll, 1a ... base plate, 1b ... spiral wall, 2
…… Fixed scroll, 2a …… Base plate, 2b …… Swirl wall, 10…
... relief port, C ... compression chamber. In the drawings, the same reference numerals indicate the same or corresponding parts.

Continuation of front page (72) Inventor Yasuyuki Suzuki 6-5-66 Tehira, Wakayama-shi, Wakayama Mitsubishi Electric Corporation Wakayama Works (56) References JP-A-2-19678 (JP, A) JP-A-1 −294984 (JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) F04C 18/02

Claims (1)

(57) [Scope of request for utility model registration] 1. A fixed scroll having a spiral wall formed on a base plate and an orbiting scroll are combined, and the orbiting scroll is turned to compress the two scrolls surrounded by the base plate and the spiral wall. In a scroll compressor, the volume of the compression chamber is reduced by moving the chamber to the center of the two scrolls, and the compression chamber communicates with a discharge hole provided at the center of the fixed scroll. A relief means for releasing the compressed fluid to the discharge space, the relief means being a pair of radially innermost symmetrical compression chambers communicating with the discharge holes for the first time and 360 ° from the radially outer end. Out of the compression chambers at the intermediate portion except for a pair of symmetrical compression chambers formed by the spiral wall, the outermost compression chambers adjacent to the radially innermost compression chambers communicating with the discharge holes for the first time, respectively. A pair of symmetrical compression chambers, a pair of symmetrical holes provided in the fixed scroll base plate closest to the radially innermost compression chamber and a set pressure provided in the pair of holes are higher than the set pressure provided in the pair of holes. A scroll compressor formed from an open valve.