JPS5836196B2 - rotary compressor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a rotary compressor, and more particularly to a rotary compressor in which the refrigerating capacity can be changed in the same model.

[Technical background of the issue and its problems] Generally, when changing the refrigerating capacity of a rotary compressor, the size of the cylinder remains constant and the amount of eccentricity of the eccentric part of the rotating shaft is changed. There are many.

In this case, the radial end face width of the rotating body changes as the eccentricity of the eccentric portion changes, and the rotation The radial end face widths of the bodies were largely different.

This change in the width in the radial direction may reduce or increase the ability to supply oil to the rotating body, or there is a risk that refrigerant may leak from between the rotating bodies or the like.

As a result, the refrigerant capacity did not meet the intended purpose or mechanical galling occurred, making it impossible to obtain a rotary compressor with good characteristics.

In other words, this type of rotary combustor includes a cylinder chamber and a frame lower end plate (cylinder side plate) that covers the upper and lower ends of the cylinder.
The refrigerant is compressed by eccentrically rotating a rotating body fitted to an eccentric portion of a rotating shaft within a cylinder chamber.

The lubricating oil is supplied from an oil reservoir at the bottom of the sealed case to the crank chamber, which is a space created between the rotary body and the rotary shaft, by utilizing the rotation of the rotary shaft, and then from the crank chamber to the crank chamber, which is a space created between the rotary body and the rotary shaft. Oil is supplied into the cylinder chamber through the gap between the end surface of the rotating body under the ground, the frame, and the lower end plate by the pressure difference.

The amount of oil supplied into the cylinder chamber can be considered by applying a general formula for fluid flowing between parallel plates.

That is, a fluid flowing through a rectangular cross section as shown in FIG. 6 is expressed by the following equation.

However, Q2 flow rate 2a: Long side length 2b: Short side length p1: Inlet side pressure p2: Outlet side pressure
U: Viscosity coefficient t2 Distance from inlet to outlet From the above formula (1) ■ Flow rate Q is inversely proportional to the distance t from inlet to outlet ■ Flow rate Q is proportional to the length of the long side 2a ■ Flow rate Q is short It can be understood that the flow rate Q is proportional to the cube of the side length 2b.It can be understood that the flow rate Q is proportional to the pressure difference p1-p2.

Applying this to the rotary compressor, Q: Oil supply amount 2a: Circumferential length of the rotating body 2b = Gap between the end face of the rotating body, frame, and lower end plate p1: Pressure inside the crank chamber p2: Pressure inside the cylinder chamber t This is the radial end face width of the two rotating bodies, and it can be seen that the amount of oil supplied is proportional to the radial end face width of the rotating body.

Therefore, as mentioned above, if the end face width of the rotating body becomes larger than the appropriate value, the amount of oil supplied into the cylinder chamber will decrease, and the sealing performance between the outer circumferential surface of the rotating body and the inner circumferential surface of the cylinder will be impaired. The high-pressure refrigerant on the compression side of the cylinder chamber flows back to the low-pressure side (suction side), reducing the refrigerating capacity and lowering the coefficient of performance, as well as causing phenomena such as mechanical galling and seizure.

On the other hand, if the width of the end face is larger than the appropriate value, the amount of oil supplied will increase and lubrication will be good, but this lubricating oil will be mixed with the high-pressure refrigerant in the crank chamber, causing a large amount to enter the cylinder chamber. When the high-pressure refrigerant flows into the cylinder chamber and expands in the low-pressure cylinder chamber, it prevents the refrigerant from being sucked into the cylinder chamber from the suction hole, reducing the refrigerating capacity and the coefficient of performance.

FIG. 7 shows the results of an experiment conducted by the applicant, and is a characteristic diagram when the end face width of the rotating body was varied while keeping the following conditions constant.

[Experimental conditions]

Cylinder chamber diameter: f54 Cylinder thickness = 25 Circumferential diameter of rotating body: f30 Eccentricity of eccentric part: 3.1 Blade thickness: 5.2 Gap between end face of rotating body, frame, and lower end plate: 24μ Discharge pressure: 2 1.0 8kg/cy4 (gauge pressure) (
Condensation temperature 54.4°C) Suction pressure: s. 4kg/c4 (gauge pressure) (evaporation temperature 7.2°C) Suction gas temperature = 35°C Degree of supercooling: 8.3°C Power supply: Single phase 100V 60Hz From this result, the radial end face width of the rotating body It is clear that the performance changes with changes in .

[Purpose of the invention]

The present invention aims to improve the above-mentioned problems and to obtain a rotary compressor that can be used with optimal characteristics even when the refrigerating capacity is changed in rotary compressors of the same mechanism.

[Summary of the invention]

The present invention maintains the radial end face width of the rotating body constant even when the refrigerating capacity of the rotary compressor is changed, thereby increasing the radial contact width between the end face of the rotating body and the cylinder side plate (frame and lower end plate). The rotary compressor is designed to maintain a constant value, and a rotary compressor with optimal characteristics can be obtained even when the refrigerating capacity is changed.

[Embodiments of the invention]

An embodiment of the present invention will be described in detail below with reference to the drawings.

In FIG. 1, the rotary compressor shown as a whole by 1 has an electric motor 3 disposed above the inside of the sealed case 2, and a compressor 4 rotatably driven by the front electric motor 3 below the inside 1 of the sealed case 2. .

Although not shown, the electric motor 3 is composed of a stator and a rotor, and the rotor has a rotary shaft 7 which protrudes through a frame 5 fixed to the sealed case 2 and has an eccentric rotating part 6, which is rotatably attached to the rotor. establish.

The compressor 4 also includes a cylinder 8 having a cylindrical inner surface, the frame 5 which is a cylinder side plate covering the upper and lower ends of the cylinder 8, and a lower end plate 9 that constitute a cylinder chamber 10. The rotating body 11 is fitted and held by the eccentric portion 6 of the rotating shaft 7 and rotates while being inscribed in the cylinder chamber 10.

In such a rotary compressor, the refrigerating capacity is, for example, 1750 Katl/h with the same model configuration.
When changing from 3000 Km/h to 3000 Km/h, it is necessary to change the amount of eccentricity of the eccentric portion 6 of the rotating shaft 7.

Cylinder interior diameter 54mm. When the cylinder thickness is 25 mm and the minimum refrigerating capacity is 1750 Kcal/h, the minimum eccentricity is 2.5 mm. At a maximum refrigerating capacity of 3000 Km/h, it is necessary to set the maximum eccentricity to 4.4.

For this reason, the radial end face width of the rotary body, which is the radial contact width between the end face of the rotary body 11 fitted and held by the eccentric portion 6 and the subgrade end plate, becomes different. In order to make the contact widths in the radial direction between the end surface of the rotating body 11 and the upper and lower end plates 5 and 9 substantially the same, the upper and lower inner end surfaces are chamfered at the C portion as shown in FIG. As shown in Figure 3, the part e is machined to provide relief so that even if the contact widths are b and d, they are maintained at a, respectively.

In Fig. 1, reference numeral 12 designates an oil supply hole for supplying oil stored in the lower part of the sealed case 2 into the cylinder chamber 10 or to the rotating shaft, and reference numeral 13 designates a fixing bolt for fixing the upper and lower end plates 5, 9 and the cylinder. .

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

To compress the refrigerant, the rotating shaft 7 is rotated by the electric motor 3, and the eccentric portion 6 thereof is rotated, for example, in a clockwise direction.

This rotation causes the rotating body 11 fitted to the eccentric part 6 to rotate clockwise, sucking refrigerant through a suction hole (not shown), compressing it in the cylinder chamber 10, and supplying the compressed refrigerant to the refrigeration cycle via a discharge valve (not shown). Let's send it in.

In a compressor that performs this function, in order to change the refrigerating capacity from a small capacity to a large capacity with the same structure, the eccentricity of the eccentric part 6 of the rotating shaft 7 should be changed from f1 to f2, f2, f2, etc., as shown in FIG.
Increase the size sequentially.

However, if the eccentricity of the lever is changed, the upper and lower end plates 5,
The upper and lower inner end surfaces of the rotating body 11 are chamfered or recessed so that the radial contact width a with the rotating body 9 is constant.

Therefore, the contact conditions between the end surface of the rotating body 11 and the upper and lower end plates 5, 9 of the cylinder body 10 are approximately the same, and the refrigerating capacity is changed to Q1, Q2 - Qa, etc., as shown in FIG. Even if the characteristics are changed, the compressor can be operated under the same characteristic conditions.

Therefore, the oil supply conditions between the rotating body 11 and the cylinder chamber 10 become uniform, refrigerant leakage and mechanical operating conditions become the same, and the compressor can always be operated under optimal conditions.

In the above embodiments, chamfering and the like are used to process the upper and lower inner end surfaces of the rotating body, but the present invention is not limited to this, and it goes without saying that arc-shaped cutting or the like may also be performed.

As described above, the present invention makes it possible to obtain a rotary body with a constant radial end face width even when the refrigerating capacity is changed using the same mechanism, so a rotary compressor that always has optimal characteristics can be obtained. It has practical effects that can be provided.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, in which FIG. 1 is a longitudinal sectional side view of the main part of the main body, FIGS. 2 and 3 are longitudinal sectional side views of the rotating body according to the invention, and FIG. Explanation of the amount of eccentricity with respect to the eccentric part, Figure 5 is a characteristic curve diagram showing the relationship between refrigerating capacity and rotor end face width, Figure 6 is an explanatory diagram of the formula for determining the flow rate of fluid flowing through a rectangular cross section, Figure 7 1 is a characteristic diagram showing the experimental results of the relationship between the radial end face width of a rotating body and the performance of a rotary compressor. 3...Electric motor, 5...Frame, 6.
... Eccentric part, 7 ... Rotating shaft, 8 ...
...Cylinder, 9...Lower end plate, 10...
...Cylinder chamber, 11...Rotating body.

Claims (1)

[Claims] 1. An electric motor, a rotating shaft that is rotated by the electric motor and has an eccentric part, a cylinder chamber that surrounds the eccentric part of the rotating shaft and has upper and lower side plates and an inner surface formed in a cylindrical shape, and a cylinder chamber that surrounds the eccentric part of the rotating shaft, and It consists of a rotating body that is fitted into the cylinder chamber and rotates within the cylinder chamber to suck in and compress refrigerant, and even when the refrigerating capacity is changed, the end face of the rotating body and the side plate of the cylinder remain in contact with each other in the radial direction. A rotary compressor characterized by a constant width.