JPH0442553Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a scroll-type fluid machine that can be used as a compressor, an expander, a motor, a pump, etc.

(Prior Art) An example of a conventional scroll type fluid machine is shown in FIGS. 7 to 10. In FIGS. 7 and 8, a housing 10 is composed of a front end plate 11 and a cup-shaped portion 12 fastened to the front end plate 11 by bolts 4. In FIG. Bearing 1 arranged in the center hole of front end plate 11
3 rotatably supports a main shaft 14 passing through this center hole.

A fixed scroll 15 and a movable scroll 16 are disposed within the housing 10. The fixed scroll 15 includes a side plate 151 and a spiral body 152 erected on the inner surface thereof, and the side plate 151 is fixed to the cup-shaped portion 12. The movable scroll 16 includes a side plate 161 and a spiral body 162 erected on the inner surface thereof, and the spiral bodies 152 and 162 have substantially the same shape.

The movable scroll 16 and the fixed scroll 15 are engaged with each other as shown in the figure with the spiral bodies 162 and 152 facing inward, respectively, with an angular deviation of 180 degrees, thereby forming a pair of closed chambers 251 and 252 at the target positions. is formed.

The movable scroll 16 is connected to the drive mechanism 6 and the rotation prevention mechanism 7, and revolves around a predetermined circular orbit as the main shaft 14 rotates. When the movable scroll 16 revolves on a predetermined circular orbit, the line contact portion between the spiral bodies 152 and 162 moves toward the center of the spiral along the surface of each spiral body 152, 162, and as a result, Both scrolls 1
Closed chamber 2 formed by meshing of 5 and 16
51 and 262 move toward the center of the spiral while decreasing their volume.

Therefore, the fluid flowing into the suction chamber 18 from the external fluid circuit through the suction port (not shown) is taken into the respective closed chambers 251, 252 from the outer end openings of the spirals of both the spiral bodies 152, 162, and is compressed. After that, the through hole 15 bored in the side plate 151 of the fixed scroll 15 is opened from the discharge small chamber 253 in the center.
4 into the discharge chamber 19 and from there exits via the discharge port 22 to the external fluid circuit.

When this scroll compressor is used as a compressor for a car cooler, the driving force from the car engine is transmitted to the main shaft 14 via the belt and clutch pulley 5, so the refrigerating capacity of the car cooler is proportional to the engine speed. It increases almost linearly in proportion to the increase. This increases the work of the compressor, which reduces the running efficiency of the vehicle, or causes the vehicle to become too cold due to excessive refrigerating capacity.

In order to solve such problems, a capacity control mechanism is provided. That is, the fixed scroll 15
Bypass holes 30a, 30c, 30b, 30d of the same diameter pass through the side plate 151 of the movable scroll 16 and are simultaneously closed by the tip end surface of the spiral body 162 of the movable scroll 16.
is drilled. 30a and 30c are spiral bodies 1
The bypass hole 30 opens into the closed chamber 251 on the ventral side of the spiral body 152.
b and 30d are provided on the back side of the spiral body 152 and open to the closed chamber 252 on the back side of the spiral body 152. Bypass holes 30a, 3 are provided on the outside of the side plate 151.
Actuator 32b that opens and closes 0c and actuator 32 that opens and closes bypass holes 30b and 30d.
a is arranged.

A control valve 34 is installed on the back of these actuators 32b and 32a during full load operation.
By guiding the high pressure gas in the discharge chamber 19 through the actuators 32b and 32a, the actuators 32b and 32a are simultaneously moved to the left, and the bypass holes 30a, 30c, 30
b and 30d, and during unloading operation, gas at an intermediate pressure between the suction pressure and the discharge pressure is introduced through the control valve 34 to
Spring 3 with 2b and 32a arranged behind them
5b and 35a are moved to the right at the same time by the elastic force, thereby allowing the gas in the closed chamber 251 to communicate with the communication hole 42b via the bypass holes 30a and 30c, and at the same time, the gas in the closed chamber 252 is bypassed. It communicates with the communication hole 42a through the holes 30b and 30d. The communication hole 42a communicates with the suction chamber 18 through a groove 46 bored in the inner circumference of the housing 10,
The communication hole 42b communicates with the suction chamber 18 via a groove 47.

The amount of rightward movement of the actuators 32a, 32b depends on the gas pressure acting on their back surfaces, and the lower the gas pressure, the greater the amount of movement.
The opening area of the communicating holes 42a and 42b is increased,
The amount of gas escaping during compression in the closed chambers 252, 251 increases.

(Problems to be solved by the invention) In the conventional scroll compressor described above, there are variations in processing between the springs 35a and 35b, a difference in sliding resistance between the actuators 32a and 32b, bypass holes 30a and 30c, Due to processing variations in the positions of 30b and 30d, a difference occurs in the amount of movement of actuators 32a and 32b during unloading operation.

As a result, when the pressure on the ventral side of the spiral body 162 of the movable scroll 16 becomes higher than the pressure on the back side, as shown in FIG. A rotational force F is generated. Note that Δp is the pressure difference between the dorsal side and the ventral side of the spiral body 162, l is the groove width of the spiral body 162, and h is the height of the spiral body 162.

However, in order to maintain good operation of this scroll type compressor, a pair of sealed small chambers 251 and 252 are arranged facing each other so that clockwise rotational force is always applied to the movable scroll 16 even during full load operation. Since the pressure is set and the rotation prevention mechanism 7 has a structure corresponding to this pressure, no particular problem occurs.

However, when the pressure on the dorsal side of the spiral body 162 becomes higher than the pressure on the ventral side, a clockwise rotational force F of l×h×Δp is generated in the movable scroll 16, as shown in FIG. . As a result, the movable scroll 16 receives a counterclockwise rotational force during its rotation, and often the rotation prevention mechanism 7 and the spiral winding body 15
2 and 162, and the spiral body 1
Problems such as vibrations occur due to sudden leakage of compressed gas between adjacent closed chambers separated by line contact between 52 and 162.

(Means for Solving the Problems) The present invention has been proposed to solve the above problems, and its gist is to provide fixed scrolls each having a spiral shape that is substantially the same. A pair of closed chambers is formed at the target position by engaging the movable scroll with these spiral bodies facing inward, and as the closed chambers move toward the center of the scroll, the volume increases. In a scroll-type fluid machine, the scroll-type fluid machine is equipped with a capacity control mechanism that controls the capacity by moving the scrolls relative to each other so as to reduce the amount of gas in the closed chamber, and bypassing the gas in the closed chamber to the suction side through a bypass path during compression. The capacity control mechanism is configured to bypass the fluid in both sealed chambers so that the pressure in the closed chamber on the ventral side of the spiral body of the fixed scroll is always lower than the pressure in the sealed chamber on the back side during unloading. A scroll type fluid machine characterized by the following configuration.

(Function) In this invention, when unloading, the pressure in the closed chamber on the ventral side of the fixed scroll spiral body is always lower than the pressure in the closed chamber on the back side, so the spiral body of the movable scroll is always clockwise. The movable scroll receives rotational force in the direction, but no counterclockwise rotational force acts on the movable scroll.

(Embodiment) An embodiment of the present invention is shown in FIG. The position of the communication hole 42b that communicates the bypass holes 30a, 30c that open on the ventral side of the spiral body 152 of the fixed scroll 15 with the suction chamber 18 is the same as the position of the communication hole 42b that communicates the bypass holes 30b, 30d that open on the back side of the spiral body 152 with the suction chamber. 18 is installed to the left of the position of the communication hole 42a that communicates with the communication hole 42a. Other configurations are shown in Figures 7 and 8.
It is similar to the conventional one shown in the figure, and corresponding members are given the same reference numerals.

However, when unloading, the actuator 32
The gas pressure acting on the back surfaces of actuators 32a and 32b is reduced, and accordingly, each actuator 32a and 32b
When 2b moves to the right at the same time, the bypass hole 3
The timing at which 0a and 30c communicate with the communication hole 42b is always earlier than the timing at which the bypass holes 30b and 30d communicate with the communication hole 42a. Therefore,
The pressure in the closed chamber 251 on the ventral side of the spiral body 152 of the fixed scroll 15 is always kept lower than the pressure in the closed chamber 252 on the back side of the spiral body 152. As a result, since no counterclockwise rotational force acts on the movable scroll 16, the rotation prevention mechanism 7
No collision noise is generated between the spiral winding bodies 152 and 162, and no leakage of compressed gas occurs between the closed chambers adjacent to each other at the contact line between the spiral winding bodies 152 and 162.

A second embodiment of the invention is shown in FIGS. 2 and 3.

As shown in FIG. 2, the bypass hole 30a opening on the ventral side of the spiral body 152 of the fixed scroll 15 is bored at a position shifted inward from the position of the bypass hole 30b opening on the back side. A bypass hole 30c opens on the ventral side of the spiral body 152.
is bored at a position shifted toward the outside of the spiral from the position of the bypass hole 30d that opens on the dorsal side. The rest of the structure is similar to the conventional one shown in FIGS. 7 and 8, and corresponding members are given the same reference numerals.

Thus, at the time of unloading, the bypass hole 30c opens into the closed chamber 251 at the time point A, as shown in FIG. 3, and the bypass hole 30a is closed at the time point B.
Thus, the bypass holes 30a and 30c that open on the ventral side of the spiral body 152 open into the closed chamber 251 during periods a and c, but the bypass hole 30d opens into the closed chamber 252 at the time of c, and the bypass hole 30d
is occluded at point D, thus the spiral body 15
Bypass holes 30b and 30d opening on the back side of 2 are
The closed chamber 252 is opened during the bd period.

Thus, the spiral body 15 of the fixed scroll 15
The closed chamber 251 on the ventral side of 2 is the closed chamber 25 on the dorsal side.
1 opens into the bypass holes 30b, 30d and communicates with the bypass holes 30a, 30c for a long time, so the pressure inside the closed chamber 251 is always lower than the pressure inside the closed chamber 252, and therefore, No counterclockwise rotational force is applied to the movable scroll 16.

4 to 6 show a third embodiment of the present invention.

As shown in FIGS. 4 and 6, bypass holes 30b and 30d opening on the back side of the spiral body 152 of the fixed scroll 15 or a communication hole 4 communicating therewith
The cross-sectional area of the passage 2a is smaller than the cross-sectional area of the bypass holes 30a and 30c opening on the ventral side of the spiral body 152 or the communication hole 42b communicating with the bypass holes 30a and 30c. The rest of the structure is similar to the conventional one shown in FIGS. 7 and 8, and corresponding members are given the same reference numerals.

However, when unloading, fixed scroll 15
The flow rate characteristics of the gas bypassed from the closed chamber 251 on the ventral side of the spiral body 152 through the bypass holes 30a, 30c and the communication hole 42b are as shown by the solid line in FIG. The flow rate characteristics of the gas bypassed from the closed chamber 252 through the bypass holes 30b, 30d and the communication hole 42a are as shown by the broken line in FIG. As a result. The pressure in the closed chamber 251 is always lower than the pressure in the closed chamber 252, so no counterclockwise rotational force is applied to the movable scroll.

Although not shown, the spring constant of the spring 35b disposed behind the actuator 32b that opens and closes the bypass holes 30a and 30c that open to the closed chamber 251 on the ventral side of the spiral body 152 of the fixed scroll 15 is determined by the spiral constant. A spring 35 is disposed behind the actuator 32a that opens and closes the bypass holes 30b and 30d that open to the sealed small chamber 252 on the back side of the housing 152.
It is possible to set the spring constant to be smaller than the spring constant of a, so that the pressure in the closed chamber 251 on the ventral side of the spiral body 152 is always lower than the pressure in the closed chamber 252 on the back side during unloading operation.

(Effect of the invention) In the present invention, the capacity control mechanism is double-sealed so that the pressure in the closed chamber on the ventral side of the spiral body of the fixed scroll is always lower than the pressure in the closed chamber on the dorsal side when unloading the mechanism. Since the structure is configured to bypass the fluid in the small chamber, the spiral body of the movable scroll receives clockwise rotational force during unloading, and no counterclockwise rotational force acts on the movable scroll, so the rotation prevention mechanism and No impact noise is generated between the spiral coils, and no gas leaks between adjacent closed chambers across the contact line between the spiral coils.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of main parts showing a first embodiment of the present invention, FIGS. 2 and 3 show a second embodiment of the present invention, and FIG. 2 is a cross-sectional view corresponding to FIG. 8. The top view and FIG. 3 are diagrams showing the timing of opening and closing of the bypass hole. 4 to 6 show a third embodiment of the present invention, in which FIG. 4 is a vertical sectional view of the main part, FIG. 5 is a diagram showing the flow rate characteristics of gas bypassed from the closed chamber, and FIG. The figure is a cross-sectional view taken along the - line in FIG. 4. 7 to 10 show an example of a conventional scroll compressor, in which FIG. 7 is a longitudinal cross-sectional view, FIG. 8 is a cross-sectional view taken along the line - in FIG. 7, and FIGS. 9 and 10 are The figure is an explanatory diagram for explaining the rotational force acting on the spiral body of the movable scroll. Fixed scroll...15, Spiral body...15
2. Movable scroll...16, Spiral body...16
2. Bypass path...30a, 30b, 30c, 3
0d, 42a, 42b, 46, 47, suction side...
18. Ventral closed chamber...251, Dorsal closed chamber...252.

Claims (1)

[Scope of utility model registration request] By meshing a fixed scroll and a movable scroll, each having a spiral body with substantially the same shape, with the spiral bodies facing inward, a pair of closed chambers is formed at the target position, and these closed chambers are The scrolls are moved relative to each other so that the volume decreases as the scroll moves toward the center, and the gas in the closed chamber is bypassed to the suction side through the bypass path during compression, thereby increasing the volume. In a scroll type fluid machine equipped with a capacity control mechanism,
When the capacity control mechanism is unloaded, the fluid in both sealed chambers is bypassed so that the pressure in the closed chamber on the ventral side of the spiral body of the fixed scroll is always lower than the pressure in the closed chamber on the back side. A scroll type fluid machine characterized by the following configuration.