JP2813496B2 - Scroll type fluid machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scroll type fluid machine.

[0002]

2. Description of the Related Art FIG. 3 shows an example of a conventional scroll compressor.
Describing a longitudinal sectional view, the inside of the sealed housing 8 is partitioned into a high-pressure side 44 and a low-pressure side 45 by the discharge cover 31. Inside the low-pressure side 45, a scroll-type compression mechanism C is disposed at an upper part thereof, and an electric motor M is disposed at a lower part thereof. The electric motor M includes a rotor Ma and a stator Mb. The rotor Ma is fixed to the rotating shaft 5, and the stator Mb is fixed by press-fitting the sealed housing 8. The scroll-type compression mechanism C has a fixed scroll 1 and an orbiting scroll 2. The fixed scroll 1 has an end plate 11 and a spiral wrap 12 erected on its inner surface.
A discharge port 13 is provided at a central portion of 1. The orbiting scroll 2 includes an end plate 21 and a spiral wrap 22 erected on the inner surface of the end plate 21, and a drive bush 54 is provided with a slewing bearing 73 in a boss 23 erected on the outer surface of the end plate 21.
The drive bush 5 is rotatably fitted through the
An eccentric pin 53 projecting from the upper end of the rotating shaft 5 is slidably fitted in a slide hole 55 formed in the rotary shaft 4. The fixed scroll 1 and the orbiting scroll 2 are eccentric to each other by a predetermined distance, and are engaged with each other at an angle of 180 degrees to form a plurality of closed spaces 24. The orbiting scroll 2 is slidably supported on a casing 6 fixed in a sealed housing 8, and allows the orbiting scroll 2 to revolve orbit between the orbiting scroll 2 and the casing 6, but prevents the orbiting scroll from rotating. A rotation prevention mechanism 3 including an Oldham link is provided. The fixed scroll 1 is supported by the casing 6 so as to be able to float via a support spring 32 disposed on the outer periphery of the end plate 11. Cylindrical flanges 15 and 16 project upward, and a cylindrical flange 39 projecting downward on the lower surface of the discharge cover 31 is sealed between the inner and outer seal members 37 therebetween. A back pressure chamber 40 surrounded by these is formed by tightly slidable fitting, and this back pressure chamber 40 is closed through a pressure guiding hole 41 formed in the end plate 11 while gas is being compressed. It communicates with the space 24. Here, the pressure guiding hole 41 is the wrap 1
2 is located at a point in contact with the inner diameter side. (FIG. 4). A high-pressure chamber 42 is provided on the inner peripheral side of the back pressure chamber (also called an intermediate pressure) 40.
Are formed, and a low-pressure chamber 43 is formed on the outer peripheral side. The upper end of the rotating shaft 5 is supported by an upper bearing 71 provided on the casing 6, and the lower end is supported by a lower bearing 72. In such a structure, by driving the electric motor M, the rotating shaft 5, the eccentric pin 53,
The orbiting scroll 2 is driven by an orbiting drive mechanism including the drive bush 54, the boss 23, and the like. . Then, the gas enters the low-pressure chamber 45 via the suction pipe 82 and is sucked into the closed space 24 via a path (not shown). Then, as the volume of the closed space 24 decreases due to the revolving orbiting motion of the orbiting scroll 2, the gas reaches the central portion while being compressed, and flows from the discharge port 13 to the high pressure chamber 42.
Through the high pressure side 44, from which the discharge pipe 83 and the check valve 84 contained therein are pushed open to be discharged to the outside. At this time, the fixed scroll 1 is pressed against the orbiting scroll 2 by the gas pressure in the high-pressure chamber 42 and the back-pressure chamber 40, thereby suppressing gas leakage from the closed space 24. When the liquid is sucked into the closed space 24, the fixed scroll 1 floats and escapes the liquid, thereby preventing the scroll-type compression mechanism from being damaged. In the upper figure, the high-pressure chamber 42, the back-pressure chamber 40, and the low-pressure chamber 43 are formed on the back side of the fixed scroll 1, respectively.
Orbiting scroll 2 by back pressure load based on 40 and 43
Can be pressed against the fixed scroll 1.

[0003]

In this type of scroll type compressor, the volume in the closed space 24 formed by the wraps 12, 22 meshing with each other during the orbiting movement of the orbiting scroll 2 decreases. Accordingly, the pressure increases. By the way, since the pressure guiding hole 41 opened on the inner surface of the end plate 11 is located in contact with the inner diameter side of the wrap 12, the pressure of the back pressure chamber 40 communicated with the pressure guiding hole 41 is Pressurized in the same way, wrap 22
Is at a maximum pressure just before contact with the wrap 12 at the point where the pressure guiding hole 41 is located, and then when the wrap 22 moves further toward its center, the pressure guiding hole 41 is closed under the minimum pressure. Since the pressure belongs to the space 24, the pressure in the back pressure chamber 40 becomes minimum, and the pressure fluctuates greatly as shown in FIG. Therefore, since the pressure in the back pressure chamber 40 greatly fluctuates, a stable back pressure load cannot be applied to the end plate 11, and there is a possibility that gas leaks from the closed space 24.

[0004] The present invention has been proposed in view of such circumstances, and is formed between the two wraps by minimizing pressure fluctuations in the back pressure chamber and applying a stable back pressure load to the end plate. It is an object of the present invention to provide a high performance scroll type fluid machine that prevents gas leakage from a closed space.

[0005]

For this purpose, the present invention provides a closed space formed by interlocking a fixed scroll and an orbiting scroll in which spiral wraps are provided upright on the inner surface of each end plate. The fixed scroll or the orbiting scroll is pressed against the orbiting scroll or the fixed scroll by a fluid pressure introduced from the sealed space through a pressure guiding hole into a back pressure chamber formed on the back side thereof. In the type fluid machine, the pressure guiding hole opened on the inner surface of the one end plate is separated from the position in contact with the inner diameter side or the outer diameter side of the one wrap by a dimension smaller than the width of the other wrap. It is characterized by being located.

[0006]

According to this structure, the pressure in the back pressure chamber rises as the volume of the closed space to which the pressure guiding hole belongs decreases in the process of the orbiting scroll revolving orbiting. When the pressure becomes small, the pressure guide hole is blocked by the orbiting scroll or the fixed scroll wrap, and the closed space and the back pressure chamber are shut off. When the wrap does not rise and the wrap moves further toward its center, the pressure-guiding hole opens into another enclosed space and the back pressure chamber communicates with the enclosed space, the volume of the enclosed space has already been reduced to some extent. The pressure in the back room does not decrease so much. That is, since the period in which the pressure guiding hole is shielded by the wrap is prolonged, the pressure fluctuation in the back pressure chamber is reduced as compared with that in the closed space.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing a scroll portion, and FIG. 2 is a diagram showing pressure changes in a closed space and a back pressure chamber according to FIG. In the upper drawing, the same reference numerals as those in FIGS. 3 and 4 denote the same members, respectively. First, in FIG. 1, the wrap 12 and the orbiting scroll 2 erected on the inner surface of the end plate 11 of the fixed scroll 1 are shown. And a pressure guiding hole 41 for communicating between the closed space 24 and the back pressure chamber 40 (FIG. 3) is opened in the inner surface of the end plate 11. The pressure guiding hole 41 is opened from a point A in contact with the inner diameter side of the wrap 12 to a point inward, and in this example, on a tangent line L in contact with the base circle Q, and the wrap of the orbiting scroll 2. 2
When the wrap 22 abuts on the point A, the pressure guide hole 41 is shielded by the wrap 22 so as not to protrude from the point A. The other structure is the same as the conventional structure shown in FIGS.

According to such a structure, as shown in FIG. 2, as the volume of the closed space 24 to which the pressure guiding hole 41 belongs decreases during the orbiting movement of the orbiting scroll 2, the back pressure chamber 40 is provided. Although the pressure inside increases, the pressure guiding hole 41 is shielded by the wrap 22 of the orbiting scroll 2 at the point a where the closed space 24 has a certain volume, so that the closed space 24 and the back pressure chamber 40 are shut off. Even if the pressure in the closed space 24 further increases as shown by the broken line, the pressure in the back pressure chamber 40 does not increase as shown by the solid line. Further, as the wrap 22 of the orbiting scroll further moves toward its center, the pressure guiding hole 41 belongs to another closed space 24, and at the point b where the back pressure chamber 40 communicates with the closed space 24, the closed space 24 is already closed. The pressure in the back pressure chamber 40 does not decrease so much because the volume of the pressure chamber 24 is reduced to some extent and the pressure is increased. That is, since the period in which the pressure guiding hole 41 is shielded by the wrap 22 of the orbiting scroll is lengthened, the pressure fluctuation in the back pressure chamber 40 is reduced as compared with the inside of the closed space 24, and accordingly, the end plate 11 The longer the pressure guiding hole 41 that is opened on the inner surface of the back cover 40 is away from the point A, the longer the period in which the pressure guiding hole 41 is shielded by the wrap 22 of the orbiting scroll, so that the pressure fluctuation in the back pressure chamber 40 decreases as indicated by the solid line. . In this embodiment, the pressure guiding holes 4
1 is located at a point inward from a point A contacting the inner diameter side of the wrap 12 of the fixed scroll 1, and the width of the wrap 22 from the point contacting the outer diameter side of the wrap 12 outward. In a compressor having a back pressure chamber on the back surface of the orbiting scroll 2, the pressure-guiding hole 41 is located at the end plate 2 of the orbiting scroll 2.
In this case, it is located between the point in contact with the inner or outer diameter side of the wrap 22 of the orbiting scroll 2 and the width of the wrap 12 of the fixed scroll 1.

[0009]

According to such a structure, the pressure-guiding hole opened on the inner surface of the end plate of the fixed scroll or the orbiting scroll is positioned from the point where it comes into contact with the inner or outer diameter side of the wrap of the fixed scroll or the orbiting scroll. Since it is located up to the width dimension of the other wrap, the period in which the pressure guiding hole is blocked by the wrap becomes longer and the pressure fluctuation in the back pressure chamber decreases, so that a stable back pressure load is applied to the fixed scroll or the orbiting scroll. Can be loaded and prevent gas leakage from enclosed space

In short, according to the present invention, the fixed scroll and the orbiting scroll, each having a spiral wrap standing on the inner surface of each end plate, are engaged with each other to form a closed space, and the fixed scroll or the orbiting scroll is formed. A scroll-type fluid machine configured to press a scroll toward the orbiting scroll or the fixed scroll by a fluid pressure introduced from the sealed space through a pressure guiding hole into a back pressure chamber formed on a back side thereof, By positioning the pressure guiding hole opened on the inner surface of the one end plate by a distance smaller than the width of the other wrap from a position in contact with the inner diameter side or the outer diameter side of the one wrap, High performance that minimizes pressure fluctuations in the back pressure chamber, applies a stable back pressure load to the end plate, and prevents gas leakage from the enclosed space formed between both wraps. The present invention from getting a scroll type fluid machine is extremely beneficial in industry.

[Brief description of the drawings]

FIG. 1 is a horizontal sectional view showing a scroll unit according to an embodiment of the present invention.

FIG. 2 is a diagram showing pressure changes in a closed space and a back pressure chamber in FIG. 1;

FIG. 3 is an overall vertical sectional view showing a conventional scroll compressor.

FIG. 4 is a horizontal sectional view showing a scroll section of FIG. 3;

FIG. 5 is a diagram showing pressure changes in a closed space and a back pressure chamber in FIG. 4;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 fixed scroll 2 orbiting scroll 11 end plate 12 lap 21 end plate 22 lap 24 closed space 40 back pressure chamber 41 pressure guiding hole

Claims (1)

(57) [Claims] 1. A fixed scroll having a spiral wrap standing on the inner surface of each end plate and an orbiting scroll are meshed with each other to form a closed space, and the fixed scroll or the orbiting scroll is disposed on the back side thereof. A scroll-type fluid machine configured to press against the orbiting scroll or the fixed scroll by a fluid pressure introduced from the closed space through a pressure guiding hole into a back pressure chamber formed at the one end plate. A scroll-type fluid, wherein the pressure-guiding hole opened on the inner surface of the scroll-type fluid is spaced apart by a dimension smaller than the width of the other wrap from a position in contact with the inner diameter side or the outer diameter side of the one wrap. machine.