JPH03182693A - Multiple stage rotary compressor - Google Patents

Abstract

PURPOSE:To reduce a cost through the common use of a part by a method wherein a rotation angle range in which a rotary compressor of a next stage performs a compression process is made smaller than that of a rotary compressor of a preceding stage. CONSTITUTION:In a rotary compression mechanism 4 of a next stage, a rolling piston 19 loosely engaged with a crank pin 6b formed such that its phase is displaced by 180 deg. to a crank pin 6a is contained in a cylinder chamber 22. The lower end of a cylinder block 17 is notched throughout a range extending in a 180 deg. arc from a position near a blade 20 along the rotation direction of the rolling piston 19 to form a notch groove 30, which is communicated with a lower muffler chamber 27 through a gas passage 31. Since, in the rotary mechanism 4 of a next stage, a compression stroke is not started before the rolling piston 19 is rotated approximately 180 deg. based on the phase of the blade 20 to reach the terminal end of the notch groove 30, displacement VH of the rotary compression mechanism 4 of the next stage is made smaller than approximate a half of displacement VL of a rotary compressor of a preceding stage.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a multistage rotary compressor suitable for being installed in an air conditioner, a refrigeration system, etc.

(Prior art and its secrets 8) When a conventional single-stage rotary compressor is used as a low-temperature refrigeration compressor, the salinity of the discharged refrigerant increases, resulting in deterioration of lubricating oil, seizure of sliding parts, and damage to motor coils. It may cause problems such as burnout.

To cope with this, liquid refrigerant is injected into the compression chamber of the rotary compressor, but this brings about problems such as a decrease in volumetric efficiency and an increase in power consumption.

Therefore, a two-stage rotary pressure ms was proposed, but in a two-stage rotary compressor, the amount of geometric displacement of the high-stage rotary compression mechanism must be smaller than that of the lower-stage rotary compression mechanism. , For this purpose, Japanese Patent Application Laid-open No. 1289/1989
As shown in Japanese Utility Model No. 90, the cylinder height of the high-stage rotary compression mechanism is made smaller than that of the low-stage rotary compression mechanism, and as shown in Japanese Utility Model Application Laid-Open No. 58-46886, The rotational eccentricity of the rolling piston of the side rotary compression mechanism was made smaller than that of the lower stage rotary compression mechanism, but these are all components of the rotary compression mechanism such as the cylinder, rolling piston, blade, and rotating shaft. Since the basic dimensions of the parts had to be changed between the high-stage side and the low-stage side, the 11 parts could not be made common, resulting in a problem of increased costs.

(Means for Solving the Problems) The present invention was invented to solve the above problems, and the gist thereof is to provide a plurality of rotary compression mechanisms of the same size that are simultaneously driven by one motor. Equipped with
In a multi-stage rotary compressor that guides the gas compressed by the previous stage rotary compression mechanism to the next stage rotary compression mechanism for further compression, the rotation angle range in which the next stage rotary compression mechanism performs the compression stroke is determined by the rotation angle range in which the next stage rotary compression mechanism performs the compression stroke. This multi-stage rotary compressor is characterized by a smaller mechanism than that of the conventional rotary compressor.

(Function) Since the present invention has the above configuration, the amount of geometric displacement of the next-stage rotary compression mechanism is smaller than that of the previous-stage rotary compression mechanism.

Embodiment One embodiment of the present invention is shown in FIGS. 1-7.

As shown in FIGS. 1 to 5, a motor 2, a previous stage rotary compression mechanism 3 and a next stage rotary compression mechanism 4 which are simultaneously rotationally driven by the motor 2 are housed in the housing 1. .

The motor 2 includes a stator 5 fixed to a housing 1 and a rotor 7 fixed to a shaft 6.

The rotary compression mechanism 3 at the front stage consists of a cylinder block 8, a lower bearing 9, a partition plate 10, a rolling piston 11, a blade 12, a pressing spring 13, etc. A rolling piston 11 loosely fitted into the crank bin 6a of the shaft 6 is housed in the limited cylinder chamber 14 so as to be eccentrically rotatable, and a blade 12 supported by the cylinder block 8 so as to be freely retractable is pushed from behind by a roller 13. A compression chamber 15 is created on one side of this blade 12 by pushing the blade 12 and sliding its tip against the outer peripheral surface of the rolling piston 11.
and a suction chamber 16 on the other side.

The next stage rotary compression mechanism 4 is a cylinder pro, ri 17,
Upper bearing 18, partition plate 10, and rolling piston 1
A rolling piston 19 is housed in a cylinder chamber 22 and is loosely fitted into a crank bin 6b which is formed 180'' out of phase with respect to the crank bin 6a. , blade 20
A compression chamber 23 is delimited on one side and a suction chamber 24 is delimited on the other side.

The shaft 6 passes through the partition plate IO and is rotatably supported by a lower bearing 9 and an upper bearing 1H.

The lower bearing 9, cylinder block 8, partition plate 10, cylinder block 17, and upper bearing 19 are integrally fastened by a plurality of ports 25 passing through them.

By fixing the cover 26 to the lower end of the rib 9a extending downward from the outer peripheral edge of the lower bearing 9, the lower muffler chamber 27
An upper muffler chamber 29 is formed by covering the upper surface of the upper bearing 18 with a cover 28.

As shown in FIG. 3, extend the lower end of the cylinder block 17 along its inner peripheral surface from the vicinity of the blade 20 for approximately 180 degrees along the rotational direction (indicated by the arrow) of the rolling piston 19.
A notch groove 30 is formed by notching across ”,
This cutout groove 30 communicates with the lower muffler chamber 27 via one or more gas passages 31 passing through the partition plate lO, the cylinder block 8, and the lower bearing 9.

When the motor 2 is started, the shaft 6 rotates, and the rolling piston 11 loosely fitted in the crank pin 6a moves eccentrically in the direction of the arrow in the cylinder chamber 14.
Rolling piston 19 loosely fitted into crank bin 6b
rotates eccentrically within the cylinder chamber 22.

Then, the gas is sucked into the suction chamber 15 of the rotary compression mechanism 3 in the previous stage through the suction pipe 32, and at the same time, the gas in the compression chamber 16 is compressed. When the gas pressure in the compression chamber 16 reaches a predetermined value, the gas passes through the discharge port 33 provided in the lower bearing 9, pushes open the discharge valve (not shown), enters the lower muffler chamber 27, and is discharged there. Pulsations in the gas are alleviated.

Next, this discharged gas passes through the gas passage 31 and enters the suction chamber 23 through the notched groove 30 of the rotary compression mechanism 4 at the next stage. However, the rolling piston 19
Since the suction chamber 23 and the compression chamber 24 are in communication via the notch groove 30 until the suction chamber 23 and the compression chamber 24 reach the end of the notch groove 30 through eccentric rotation, the gas is not compressed.

When the rolling piston 19 reaches the end of the notched groove 30, the compression chamber 24 is cut off from the suction chamber 23, a compression stroke begins, and the gas in the compression chamber 24 is compressed. When the gas pressure in the compression chamber 24 reaches a predetermined value, the gas passes through the discharge port 34 provided in the upper bearing 19, pushes open a discharge valve (not shown), enters the upper muffler chamber 29, and enters the upper muffler chamber 29. Pulsations in the discharged gas are alleviated.

Next, this gas flows out from an outlet (not shown) into the space 35 formed between the motor 2 and the next-stage rotary compression mechanism 4, where the pulsation component is further removed and the gap between the stator 5 and rotor 7 of the motor 2 is removed. and a gas passage 3 penetrating the stator 5
6, enters a space 37 formed above the motor 2, further removes pulsating components, and is discharged to the outside of the housing l via a discharge pipe 38. Then, after circulating through the condenser, expansion valve, evaporator, accumulator, etc. of the refrigeration system, it is sucked in again from the suction pipe 32.

The mist of lubricating oil contained in the discharged gas flows through spaces 35 and 3.
7 and separated by a plurality of holes 38 passing through the cylinder block 17 and a plurality of holes 39 passing through the cylinder block 8.
The liquid then falls and is stored at the bottom of the housing 1.

In addition, 40 is a liquid injection tube for injecting liquid refrigerant into the compression chamber 16 of the rotary compression mechanism 3;
is a liquid injection tube that injects liquid refrigerant into the compression chamber 24 of the rotary compression mechanism 4 of the next stage.

The gas pressure sucked into the rotary compression mechanism 3 in the previous stage is P5.
, if the gas pressure discharged from the next-stage rotary compression mechanism 4 is P, then the optimal intermediate pressure, that is, the gas pressure discharged from the previous-stage rotary compression mechanism 3 and the gas pressure sucked into the next-stage rotary compression mechanism 4. The resulting gas pressure P is expressed as P, = q2.

Then, in the next stage rotary compression mechanism 4, the rolling piston 19 rotates about 1800 times based on the phase of the blade 20 until it reaches the end of the notched groove 35, that is, the cutoff point of the suction stroke or the start point of the compression stroke. does not start the compression stroke, the displacement VH of the rotary compression mechanism 4 in the next stage is approximately half of that vL of the rotary compression mechanism 3 in the previous stage, and the in-cylinder pressure P of the rotary compression mechanism 4 in the next stage
C, I and the cylinder pressure P of the rotary compression mechanism 3 in the previous stage, 18
changes as shown in FIG. 6 in accordance with the rotation of the shaft 6.

Note that the end position of the notch groove 30 is set to the rolling piston 11.
The cutoff point of the suction stroke, that is, the rotation angle range of the compression stroke can be arbitrarily adjusted by moving the rotation direction of the suction stroke.

The volume of the next-stage rotary compression mechanism 4 before suction is closed, that is, the sum of the volumes of the suction chamber 23 and the compression chamber 24, which communicate with each other via the notch groove 35, acts as a buffer volume, and the volume of the rotary compression mechanism 4 of the previous stage is This helps to alleviate pressure pulsations in the gas discharged from the compression mechanism 3.

Furthermore, when the liquid refrigerant is injected into the compression chamber 16 of the rotary compression mechanism 3 in the previous stage through the liquid injection pipe 40, the temperature T5 of the refrigerant gas sucked into the rotary compression mechanism 4 in the next stage increases.
, becomes lower than the temperature T1 of the refrigerant gas discharged from the rotary compression mechanism 3 at the previous stage, and accordingly, the temperature T of the gas discharged from the rotary compression mechanism 4 at the next stage. can be kept low. If this is expressed in a Mollier diagram, it will be as shown in FIG. 7.

In Fig. 7, SL is the suction port DL of the rotary compression mechanism 3 in the previous stage, discharge port SN of the rotary compression mechanism 3 in the previous stage is the suction port DH of the rotary compression mechanism 4 in the next stage, and SL is the suction port DL of the rotary compression mechanism 3 in the previous stage. The discharge port In is the outlet port Ex for the injected liquid refrigerant, and each position of the inlet of the expansion valve is shown.

A second embodiment of the invention is shown in FIGS. 8 and 9.

By erecting a rib 42 rising upward from the outer peripheral edge of the upper bearing 1, and erecting a rib 43 extending in the diametrical direction above the blade 20, and fixing a cover 44 to the upper surface of these ribs 42,43. An upper muffler chamber 45 is formed on one side of the rib 43, that is, the discharge port 34 side, and an intermediate chamber 46 is formed on the other side of the rib 43.

This intermediate chamber 46 includes the upper bearing 18 and the cylinder block 17.
It communicates with the lower muffler chamber 27 via a gas passage 47 passing through the partition plate lO, the cylinder block 8, and the lower bearing 9, and also via two gas ill passages 48 and 49 bored in the upper bearing 18. It communicates with the compression chamber 24 of the rotary compression mechanism 4 at the next stage. One gas passage 48 opens at a position close to the blade 20, and the other gas passage 48 opens at a position close to the blade 20.
Reference numeral 9 opens at a position offset from the blade 20 by approximately 180''. Reference numeral 50 indicates a discharge valve, and 51 indicates a gas passage 48.4.
9 to the cylinder chamber 24 smoothly.

The other configurations are the same as those of the first embodiment except that the notch Y1430 and the gas ill passage 31 are not provided, and corresponding members are given the same reference numerals.

Thus, the gas discharged from the rotary compression mechanism 3 in the previous stage enters the intermediate chamber 46 through the lower muffler chamber 27 and the gas passage 47, and passes through the gas passages 48 and 49 into the cylinder chamber 22 of the rotary compression mechanism 4 in the next stage. inhaled into the body. However, the rolling piston 19 eccentrically rotates and the gas i
After reaching the opening position of the Il passage 49, that is, a position approximately 180'' out of phase with the blade 20, and cutting off the cylinder chamber 22 from the intermediate chamber 46 to stop gas intake, the compression stroke is started. The gas passes through the discharge boat 34, pushes open the discharge valve 50, enters the upper muffler chamber 45, and is discharged into the space 35 through an outlet (not shown).Gas passage 4
By moving the opening position of the piston 9 along the rotation direction of the rolling piston 19, the suction cut-off position, that is, the rotation angle range of the compression stroke can be arbitrarily adjusted.

Although an example in which the present invention is applied to a two-stage rotary compressor has been described above, it goes without saying that the present invention can also be applied to a multi-stage rotary compressor having three or more stages.

(Effect of the invention) In the present invention, the rotation angle range in which the next-stage rotary compression mechanism performs the compression stroke is made smaller than that of the previous-stage rotary compression mechanism, so that the geometric displacement of the next-stage rotary compression mechanism is can be made smaller than that of the previous stage rotary compression mechanism.

As a result, there is no need to change the dimensions of the main parts constituting a large number of rotary compression mechanisms, so parts can be made common, and costs can therefore be reduced significantly.

[Brief explanation of drawings]

1 to 7 show one embodiment of the present invention, FIG. 1 is a longitudinal sectional view, and FIGS. 2 to 5 are the tr-n line, m-rM line, and ■-N line in FIG. 1. a cross-sectional view along the line V-vvA;
FIG. 6 is a diagram showing changes in cylinder pressure with respect to shaft rotation angle, and FIG. 7 is a Mollier diagram of a refrigeration cycle equipped with this multistage rotary compressor. 8 and 9 show a second embodiment of the present invention, and FIG.
The figure is a partial vertical cross-sectional view, and FIG. 9 is a cross-sectional view taken along line D (-1) of FIG. 4R Enclosed

Claims (1)

[Claims] A multistage rotary compressor is equipped with a plurality of rotary compression mechanisms of the same size that are simultaneously driven by one motor, and guides the gas compressed by the previous stage rotary compression mechanism to the next stage rotary compression mechanism for further compression. A multi-stage rotary compressor, characterized in that the rotation angle range in which the rotary compression mechanism of a stage performs a compression stroke is smaller than that of the rotary compression mechanism of the preceding stage.