JPH03260390A - scroll compressor - Google Patents

Abstract

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

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention is characterized by meshing a fixed scroll and an orbiting scroll, each having a spiral wrap, and causing the orbiting scroll to orbit relative to the fixed scroll without rotating. , a pair of sealed chambers formed between the spiral wraps of these scrolls gradually reduces the volume, so that the sucked gas is compressed and discharged from the central discharge port of the fixed scroll. The present invention relates to a compressor, and more specifically, relates to capacity control of a scroll compressor for changing the discharge capacity.

[Prior Art] Scroll compressors whose discharge capacity can be controlled as described above are disclosed in, for example, Japanese Unexamined Patent Publications No. 64-45987 and No. 64-4.
It is disclosed in Japanese Patent No. 5988 and the like. Unexamined Japanese Patent Publication 1986-45
In order to control the discharge capacity, the scroll compressor No. 987 has a turning angle position that is advanced by a predetermined turning angle commensurate with unloading operation (capacity reduction operation) from the turning angle of the turning scroll at which the closed chamber has the maximum volume. wherein at least one pair of bypass holes are provided in the end plate of the fixed scroll, the bypass holes communicating with the suction chamber being closed simultaneously by the orbiting motion of the orbiting scroll for each of the sealed chambers forming the pair; Each bypass hole is provided with a respective piston for simultaneously opening and closing the communication between the suction chamber and each sealed chamber via each of these bypass holes, and gas pressure for opening and closing the piston is provided on the back surface of each piston. A gas introduction path is provided for the action of the gas.

Furthermore, in order to similarly control the capacity, JP-A No. 64-45988 discloses a capacity control type in which each bypass hole is connected by a bypass pipe on the outside of the fixed scroll hole, and these bypass pipes are provided with on-off valves. This relates to a scroll compressor.

In the scroll compressor configured as described above, if these bypass holes are shut off by pushing down the piston or closing the on-off valve, there is no gas to bypass, so gas compression is stopped from the beginning when the maximum volume compression chamber is formed. The compressor starts and operates at full load like a conventional compressor.

On the other hand, when the bypass hole is opened and communicated with the piston or on-off valve, from the time when the maximum volume compression chamber is formed until the orbiting scroll rotates to the position where the bypass hole is closed,
The gas is bypassed to the suction chamber and is not compressed; only subsequent turns of the orbiting scroll compress the gas. Therefore, the discharge capacity also decreases, resulting in an unload operation.

[Problems to be Solved by the Invention] By the way, in the former scroll compressor, during unload operation, the working gas to be compressed is as follows.

The biasing force of the spring causes a bypass between the wraps of the fixed scroll, but by bypassing, the pressure in the sealed chamber between the wraps approaches the suction pressure, and the piston is then pushed by the spring in the direction of closing the bypass hole. As a result, the working gas cannot be bypassed efficiently and losses increase. In addition, the end point of the wrap outer line of the fixed scroll is at or slightly beyond the point where the sealed chamber between both scroll wraps has the maximum volume, that is, the wrap outer line of the fixed scroll reaches such a point. When the fixed scroll has a wrapped spiral shape that extends only a short distance (in the case of a fixed scroll wrapped shape as shown in Fig. 2), the suction chamber and the sealed chamber are communicated through the wrap as described in the publication. A pair of bypass holes cannot be provided in the fixed scroll end plate.

On the other hand, in the latter type of scroll compressor, since a bypass pipe is provided, during full-load operation, the bypass pipe is filled with working gas, and there is interference due to re-expansion of this gas, resulting in a decrease in volumetric efficiency. There are also problems such as a decrease in capacity due to the increase in temperature of the working space, an increase in the temperature of the discharged gas, and an increase in the temperature of the motor windings.

SUMMARY OF THE INVENTION An object of the present invention is to solve the various problems mentioned above in the known capacity control scroll compressor, particularly the problem of unnecessary losses. That is, an object of the present invention is to provide a scroll compressor in which working gas can be reliably bypassed without pressure loss during unload operation, and there is no interference with the working gas due to a bypass pipe during full load operation.

[Means for Solving the Problems] In order to solve the above problems, the present invention provides a scroll compressor as set forth in each claim.

[Function] When the pressure for actuating the control piston valve is applied to the back surface of the control piston valve, the piston valve closes all bypass holes.

Therefore, there is no gas to bypass and full load operation is possible.

In this case, since a bypass pipe as in the conventional case is not provided, there is no interference due to re-expansion of the working gas as described above.

When the pressure for actuating the control piston is reduced or eliminated, the control piston valve opens and the bypass passage opens. Therefore, it becomes an unload operation.

[Example] The present invention will be explained in detail below.

FIG. 1 shows a sectional view of the entire structure of a hermetic scroll compressor embodying the present invention.

In FIG. 1, a compressor section 2 is disposed above and an electric motor 3 is disposed below inside a closed container 1, and an oil reservoir 4 for lubrication is formed at the bottom of the closed container 1. The compressor section 2 includes a fixed scroll 5 having a spiral wrap 5a on the end plate, and a spiral wrap 6 on the end plate.
The rotating scroll 6 has a frame 7 that is integrated with the fixed scroll 5 and supports the orbiting scroll 6, and the lamps of the fixed scroll 5 and the orbiting scroll 6 are engaged with each other. Further, an Oldham mechanism 8 is provided between the orbiting scroll 6 and the frame 7 to prevent rotation of the orbiting scroll 6'. The electric motor 3 is press-fitted into the closed container 1 and rotates the orbiting scroll 6 via the crankshaft 9. The crankshaft 9 is supported by an upper main bearing 10 and a lower main bearing 11 provided on the frame 7, and its crank pin is fitted into an orbiting bearing 12 provided on the back surface of the orbiting scroll 6.

Inside the crankshaft 9 is an upper main bearing 10. A lubricant passage 13 is provided to guide lubricating oil to the lower main bearing 11 and the swing bearing 12, and at the lower end of the shaft (crankshaft) 9 of the electric motor 3, a lubricant is provided to suck up the lubricating oil from the oil reservoir 4 and send it to the lubricant passage 13. A device 14 is provided.

In the compressor section 2, when the orbiting scroll 6 is rotated via a crankshaft 9 driven by an electric motor 3, a symmetrical pair of closed spaces formed by the orbiting scroll 6 and the fixed scroll 5 are formed. As the compression chamber moves toward the center of the scroll, its volume decreases to compress the sucked refrigerant gas. The compressed refrigerant gas is discharged from a discharge port 16 provided at the center of the end plate of the fixed scroll to an upper space 17 within the closed container.

Furthermore, an intermediate pressure chamber 15 is formed on the back surface of the orbiting scroll to which refrigerant gas for the compression stroke is guided. Intermediate pressure chamber 1
The pressure No. 5 is an intermediate pressure between the suction pressure and the discharge pressure of the refrigerant gas, and oil supply to the m moving part of the scroll is performed using the differential pressure between the discharge pressure and the intermediate chamber pressure. The lubricating oil passes through the oil supply passage 13 by the oil supply device 14, lubricates the lower main bearing 11, the upper main bearing 10, and the swing bearing 12, and then flows into the compression chamber via the intermediate pressure chamber 15, where it is mixed with refrigerant gas. The liquid is discharged from a discharge port 16 provided at the center of the fixed scroll 5 into an upper space 17 within the closed container l.

A groove 18 extending in the axial direction (vertical direction) is provided between the frame 7 and the inner wall of the airtight container 1 on the outer periphery of the frame 7, so that the refrigerant gas in the upper space 17 can be transferred to the compressor section 2. It is designed to lead to the space below.

In FIG. 1, reference numeral 20 denotes a suction pipe for penetrating the closed container 1 and guiding refrigerant gas from the outside of the closed container 1 to the suction side of the compressor section 2. Reference numeral 21 denotes a discharge pipe connected to a space between the compressor section 2 and the electric motor 3 in the closed container 1, and compressed refrigerant gas flows out of the closed container 1 from this discharge pipe.

Furthermore, in this embodiment, as shown in FIGS. 1 and 2, the end plate of the fixed scroll 5 is provided with a pair of bypass holes 5b and 5b' and a pair of bypass holes 5c and 5c'.

These bypass holes are located at a rotation position where the orbiting scroll has advanced by a predetermined rotation angle commensurate with the unloading operation from the orbiting scroll rotation angle at which the sealed chamber reaches its maximum capacity. A pair of first bypass holes 5b and 5C are provided along the inner line and outer line of the fixed scroll wrap 58, respectively, so that they can be closed simultaneously by the turning movement of the fixed scroll. A second bypass hole 5b' corresponding to the bypass hole 5b along the inner line of the fixed scroll wrap 5a is provided along the inner line of the fixed scroll wrap, and a second bypass hole 5b' corresponding to the bypass hole 5c along the outer line of the fixed scroll wrap 5a is similarly provided.
A bypass hole 5c' is provided along the outer line of the fixed scroll wrap 5a. Bypass holes 5b' and 5c' are respectively.

The winding angle of the fixed scroll wrap is provided at a position advanced by 2π radians or approximately 2π radians from the bypass holes 5b and 5c, respectively. These holes 5b.

A plurality of 5b', 5c, and 5c' are formed along the inner and outer lines of the wrap. Note that the diameter of the bypass hole is set smaller than the thickness S of the wrap 6a.

FIG. 3 is a sectional view taken along arrow A-A in FIG. 2. As shown in the figure, a pair of bypass holes 5
b, 5b' are communication holes 5d that are opened and closed by one control piston valve 22 in the fixed scroll end plate.
are tied together. That is, a communication hole 5d for communicating the bypass holes 5b, 5b' is provided in the fixed scroll end plate, and a control piston valve 22 for simultaneously opening and closing the bypass holes 5b, 5b' is provided in the hole 5d. There is.

Each spring 23 that presses the piston 22 in the opening direction is interposed between the control piston valve 22 and a pedestal provided on the fixed scroll 5. Also control piston valve 2
A gas passage pipe 24 is provided for applying pressure gas for the second operation to the back surface of the control valve 22. Another pair of bypass holes 5c.

5c' is also provided with a control piston valve, a spring, and a gas passage pipe having the same structure as described above. In the first embodiment, these gas passage pipes 24 are communicated with the suction side and the discharge side of the compressor via on-off valves 25 and 26, respectively, as shown in FIG.

Next, the operation of the above embodiment will be explained.

When the electric motor 3 causes the orbiting scroll to orbit through the crank #lI9, the gas sucked from the suction pipe 2o, such as refrigerant gas, is transferred to the fixed scroll 5 and the orbiting scroll 6.
After being compressed by the action of the fixed scroll 5, it is discharged from the discharge port 16 provided at the center of the fixed scroll 5 into the upper space 17 above the closed container. This discharged refrigerant gas passes through the passage 18 provided in the frame 7 and enters the space below the compressor section, i.e.
It flows into the space between the frame 7 and the electric motor 3, and the discharge pipe 2
1 to the outside of the closed container 1.

Now, during full load operation (full load operation), the on-off valve 25 connected to the suction side is closed, and the on-off valve 26 connected to the discharge side is kept open. By doing this, the control valve 22
Since the discharge pressure gas acts on the back side of the control valve, the control valve is pushed down to the large bypass side, and the bypass holes 5b and 5b' and 5c and 5c' are not communicated with each other. This puts the compressor into full load operation.

On the other hand, in the case of unloading operation, the on-off valve 25 is opened,
By closing the on-off valve 26, suction pressure gas is introduced to the back side of the control valve 22. In this case, the control valve 22 is pushed up by the force of the spring 23 and the gas pressure in the sealed chamber, and the bypass holes 5b, 5b', and 5c
and 5c' are in communication with each other. This causes the compressor to enter unload operation. That is, the refrigerant gas in the sealed chamber flows from bypass hole 5b to 5b' and from 5c to 5c'.
The system is bypassed and unloaded.

Referring to FIG. 4B, the relationship between the crank angle and gas pressure in the above embodiment will be explained in more detail. The volume of the sealed chamber is a function of the crank angle of the crankshaft 9 that causes the orbiting scroll 6 to orbit, ie, the orbit angle of the orbiting scroll.

In a scroll compressor whose capacity cannot be controlled, the relationship between the crank angle and the pressure change of the gas until the gas is discharged from the discharge port until it is discharged from the discharge port is shown in a diagram as shown in Fig. 4. The line will look like ABC.

α1 is the crank angle when the sealed chamber is at its maximum volume, that is, at the time of starting compression, and the gas pressure in the sealed chamber at this time is the suction pressure Ps in the suction chamber. Also α2
is the crank angle at which the sealed chamber reaches its minimum volume, that is, immediately before the compressed gas is discharged, and the gas pressure in the sealed chamber at this time is called the set pressure. α3 is discharge port 1
This is the crank angle at which the discharge of compressed gas to 6 is completed.

From crank angle α2 to α3, the volume of the central region formed by the wraps of both scrolls is reduced while communicating with the discharge port 16, and the gas pressure in the central region is equal to the gas pressure at the discharge port 16 (referred to as operating pressure). )ph.

During full load operation, as shown by the solid line in Fig. 4,
)B→C-)D, the gas is compressed and discharged.

On the other hand, in the unloading operation of the above embodiment, the volume of the sealed chamber starts to decrease from the maximum volume formed at the crank angle α (compression start point) as indicated by the two-dot chain line in the figure, and the volume of the closed chamber starts to decrease. From the crank angle α at which b'y5c' communicates with the suction side, the fluid in the working chamber flows through the bypass hole 5b.
The working fluid is bypassed from the bypass 5b' to the suction side from the bypass 5c to the bypass hole 5c', and the crank angle α. reach. At the position of this crank angle α4, the wrap of the orbiting scroll finishes closing the bypass hole.

In this case, due to the pressure loss in the bypass passage system, the pressure at the position of the crank angle α becomes Ps + β, which is the sum of the suction pressure Ps and the pressure loss β in the bypass passage system.

Compression of the gas starts from the position of the crank angle α, where the volume of the sealed chamber is smaller than the maximum volume formed at the crank angle α1, and! The gas pressure inside the closed chamber at the crank angle α2 position immediately before the closed chamber communicates with the discharge port, that is, the set pressure during unload operation, is the operating pressure Ph (this is the same during unload operation as during full load operation). ) is a lower pressure than Ph'. Therefore, the gas pressure within the central region formed by both scroll wraps communicating with the discharge port 16 immediately after the position of the crank angle α2 becomes equal to the operating pressure Ph instantaneously due to the backflow of gas from the discharge port 16, and this operation The discharge of the compressed gas ends at the position of the crank angle α at the pressure ph. Therefore, in the unloading operation, the gas is compressed and discharged following the sequence of A-+E-LA'→F→B-+C4D.

In the above embodiment, opening the valve 25 and closing the valve 26 during the startup period helps reduce the startup load.

The embodiment shown in FIG. 5 is the same as the embodiment shown in FIG. 1 except for the gas pressure supply path acting on the back surface of the control piston valve 22. That is,
The gas passage 24 is connected only to the discharge side of the compressor via an on-off valve 26.

Therefore, by opening the on-off valve 26, the discharge pressure gas acts on the back surface of the control piston valve 22, and the control valve 22 is pushed down, resulting in a full load operating state. Furthermore, when the on-off valve 26 is closed, the discharge pressure gas acting on the back surface of the control valve 22 is transferred to the bypass holes 5b, 5b', 5c, and 5c'.
It leaks little by little.

As a result, the operating pressure gas on the back side of the control valve 22 decreases,
When the force of the spring 23 increases, the control valve 22 is pushed up and enters an unload operation state.

In addition, in FIG. 5, by keeping the valve 26 closed during the startup period, the effect of reducing the startup load can be obtained.

The embodiment shown in FIG. 6 is different from the embodiment shown in FIG.
The gas passage 24 is connected only to the suction side of the compressor via an on-off valve 25, and the wall of the chamber housing the control piston valve 22 has a throttle hole or A capillary 27 is bored. Therefore, by opening the on-off valve 25, low-pressure suction pressure gas acts on the back surface of the control valve 22, and the control valve 22 is pushed up by the force of the spring 23, resulting in an unload operation state.

Furthermore, when the on-off valve 25 is closed, high-pressure discharge pressure gas acts on the back side of the control piston valve 22 from the throttle hole 27 that opens and closes in the upper space 17, and the control piston valve 22 is thereby pushed down, allowing full load operation. state.

In addition, in FIG. 6, the starting load can be reduced by keeping the valve 25 open during the starting period.

In the embodiment shown in FIG. 7, the back side of the control piston valve 22 communicates with the upper space 17 through a pore 28. When the compressor is started, the pressure in the upper space [7] is low, so the piston valve 22 is pushed up, and the pressure in the compression chamber is bypassed to the suction chamber. Thereafter, as the pressure in the upper space 17 increases, the pores 2
The discharge pressure gas acts on the back side of the control valve 22 through 8, and the control valve 22 is pushed down, resulting in full load operation.

In this way, it is possible to reduce the load upon startup.

[Effects of the Invention] As described above, in the scroll compressor of the present invention, a control piston valve that straddles the pair of bypass holes and opens and closes them simultaneously is provided on the fixed scroll end plate, and the control piston valve is closed and closed. By changing the state or open state,
Both full load operation and unload operation can be performed. Moreover, unlike conventional bypass pipes that connect the bypass holes, there is no need for a bypass pipe to connect the bypass holes, so there is no re-expansion of the working gas during full load operation, and the control piston valve can be operated reliably during unload operation. The pressure loss of the working gas is also small, and no unnecessary loss occurs.

In addition, in contrast, the bypass communication passages via the paired bypass holes are closed or opened simultaneously by their respective control valves, resulting in an undesirable pressure difference between the paired sealed spaces, and the resulting load. There will be no imbalance.

Further, the present invention is also applicable to a compressor in which the fixed scroll wrap outer line extends only to a point where the sealed chamber between both scroll ramps has a maximum volume or a point slightly beyond that.

Further, by providing a plurality of first and second bypass holes, there is an effect that the pressure loss in the bypass path during unloading operation is further reduced.

[Brief explanation of drawings]

Figure 1 is a sectional view showing one embodiment of the present invention.
), (0) is a plan sectional view showing different states of engagement of both the fixed and orbiting scrolls in the same embodiment, and FIG. 3 is a detailed view of the part related to the control piston valve, and FIG. FIG. 4 is a diagram showing the relationship between crank angle and gas pressure; FIG. 6th. FIG. 7 is a sectional view showing further different embodiments of the present invention. 5. Fixed scroll 5a... Wrap 5b, 5b,
5c, 5c"...Bypass hole 5d...Communication hole
6... Orbiting scroll 22... Control piston valve 23
... Spring 24 ... Gas passage pipe 25.2
6... Open/close valve (1 other person) Figure 3 Figure 2 Figure 6 Figure 7

Claims (1)

[Scope of Claims] 1. A fixed scroll formed by vertically forming a spiral wrap on an end plate having a discharge port opening into a discharge chamber near the center position, and a fixed scroll having a spiral wrap formed on the end plate with the same curve as the spiral wrap of the fixed scroll. Means for engaging an orbiting scroll formed by standing upright spiral wraps, forming a suction chamber in the outer periphery of the engaged spiral wrap, and preventing rotation of the orbiting scroll; an orbiting scroll drive means for making an orbiting motion without rotating, and the scroll is symmetrically formed between a spiral wrap of the orbiting scroll and a spiral wrap of the fixed scroll during the orbiting motion of the orbiting scroll. In the scroll compressor, a pair of sealed chambers are moved toward the discharge port while successively decreasing their volumes, and suction gas from the suction chamber is discharged from the discharge port as compressed gas, wherein the sealed chamber is A pair of closed chambers are closed at the same time by the orbiting movement of the orbiting scroll, with respect to the pair of closed chambers at a rotation position advanced by a predetermined orbit angle commensurate with the unloading operation from the orbit angle of the orbiting scroll that has the maximum volume. No. 1 bypass holes (5b, 5c) are provided in the end plate of the fixed scroll along the inner and outer wrap lines of the fixed scroll, respectively, and bypass holes (5b, 5c) are provided in the end plate of the fixed scroll along the inner and outer wrap lines of the fixed scroll, and bypass holes (5b, 5c) are provided in the end plate of the fixed scroll along the inner and outer wrap lines of the fixed scroll, and bypass holes (5b, 5c) are provided in the end plate of the fixed scroll along the inner and outer wrap lines of the fixed scroll. A second bypass hole (5b') corresponding to the first bypass hole (5b) is provided in the end plate of the fixed scroll along the inner wrap line of the fixed scroll; A second bypass hole (5c') corresponding to the bypass hole (5c) is provided in the end plate of the fixed scroll along the wrap outer line of the fixed scroll.
The bypass holes (5b', 5c') are the first bypass holes (5b, 5c).
), the wrap angle of the fixed scroll is advanced by 2π radians or approximately 2π radians, respectively, and the end plate of the fixed scroll has these first bypass holes (5
b, 5c) and the corresponding second bypass hole (5b'
, 5c') and for simultaneously opening and closing the first and second bypass holes thereof, and applying pressure for opening and closing the valves to the back surfaces of these control piston valves. A scroll compressor characterized by comprising a pressure introduction passage. 2. The scroll compressor according to claim 1, wherein the fixed scroll end plate is provided with a spring that biases the control piston valve in the opening direction. 3 The first and second bypass holes (5b, 5b'
, 5c, 5c') are formed in plural numbers along the inner and outer lines of the wrap.