JPS6123393B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A conventional rotary compressor is shown in FIGS. 1 and 2, in which 1 is a main shaft, 2 is a cylinder,
3 is a lower bearing, 4 is an upper bearing, 5 is a rotor, 6 is a blade, 7 is a spring, 8 is a motor rotor, 9 is a stator, 10 is a casing, 11 is an upper cover, 12 is a lower cover, 13 is a stator An end coil, 14 a terminal, 15 a discharge pipe, 16 a suction pipe, 17 a discharge port, and 18 a discharge valve.

The main shaft 1 has an eccentric part where the rotor 5 fits, and as the main shaft 1 rotates in the direction of the arrow, the rotor 5
moves in the cylinder 2, and the gas sucked into the crescent-shaped gap defined by the rotor 5 and the cylinder 2 through the suction pipe 16 is stopped by the blade 6 and compressed. Then, the discharge valve 18 is pushed up and discharged from the discharge port 17.

This type of rotary compressor discharges gas from the discharge valve 18 once per rotation of the main shaft 1. The energy added to the compressed gas is provided by the eccentric rotor 5 forcing the high pressure gas.

Therefore, the shaft torque is 1 as shown in Figure 3.
The torque fluctuates according to the rotation period, and the maximum torque is 200 to 250% of the average torque. In other words, in a rotary compressor, as shown in Fig. 5, when gas pressure P acts, the product of the eccentricity e of the rotor center O' from the center O of the main shaft 1 and the component force of the component perpendicular to the eccentric direction of the gas pressure P. A torque corresponding to is applied to the main shaft 1. This torque becomes zero when the center O' of the rotor 5 is exactly in the direction of the blades 6 (directly above in Figure 2), as the gas pressure P becomes entirely equal to the suction pressure. indicates the lowest value. However, as the center O' of the rotor 5 rotates and compresses the gas, the gas pressure P increases, the torque increases, and reaches its maximum when the center O' of the rotor 5 rotates about 200 degrees from the position of the blades 6.

For this reason, the starting torque becomes large, especially when driving with a single-phase electric motor.In order to increase the starting torque, the capacity of the starting capacitor must be increased.
Not only does the shape of the squirrel cage groove of the rotor 8 of the electric motor require special consideration, but it is also necessary to sacrifice efficiency during rated operation.

In addition, large torque fluctuations may cause compressor noise.

In view of the above, the present invention has been proposed to level out fluctuations in shaft torque, and will be specifically explained below with reference to FIGS. 4 to 6.

In Fig. 4, 101 is a balance piston;
102 is a spring, 103 is a set screw, and the others are the same as the above-mentioned conventional one. This balance piston 1
01 is desirably located at a position of 135° as measured along the rotational direction of the rotor 5 from the position of the blade 6, as shown, but it can be located within the range of 135°±90°. The tip of the piston 101 is in contact with the outer peripheral surface of the rotor 5 and is pressed toward the center of the main shaft 1 by a spring 102.

When the rotor 5 rotates to compress the gas, a force shown by F in FIG. 5 is applied to the balance piston 101 by the spring 102, so that
A torque corresponding to the product of the eccentricity e and the component of the force F perpendicular to the eccentric direction is generated.

In the example shown in Fig. 4, the balance piston 101 is provided at a position 135° from the position of the blade 6, so it acts in a direction that helps the torque of the electric motor in the range of 135±91°, but in other ranges, It acts in the direction of absorbing the torque of the electric motor. The dotted line in FIG. 6 shows the torque due to the balance piston 101. Therefore, the sum of the torque curve shown in FIG. 3 and the torque curve shown by the dotted line in FIG. 6 is shown as a solid line, and this becomes the torque curve of a rotary compressor equipped with a balance piston.

As can be seen from FIG. 6, by providing a balance piston, the maximum torque can be reduced to about 1/2.

In addition, in the example of FIG. 4, the balance piston 101
The installation position of the balance piston is set at 135 degrees from the blade position, but the optimal position of the balance piston changes depending on the pressure ratio of the compressor, so it is set in the range of 40 to 180 degrees depending on the application.

Further, although one balance piston is shown in the example of FIG. 4, a large balance force can be generated by providing a plurality of balance pistons at different angles. Furthermore, although the balance piston 101 is pressed by a spring 102,
Alternatively, the discharged gas in the casing 10 can be made to act on the balance piston through the notch 104 and the through hole 105 of the set screw 103,
If necessary, a pressing force from the spring 102 may be added.

As explained above in the embodiments, in the present invention, the blades are disposed within a range of 135°±90° as measured along the rotational direction of the rotor from the position of the blades, and are pressed against the outer peripheral surface of the rotor. Since it is equipped with a balance piston, torque fluctuations can be greatly reduced.

As a result, rotational fluctuations become smaller and vibration noise can be reduced.

The starting torque is also reduced, and the groove shape of the squirrel-cage motor rotor can be selected to maximize efficiency during rated operation, improving compressor performance.

Other effects include reducing the starting current of the motor during startup.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a conventional rotary compressor, FIG. 2 is a sectional view taken along the - line in FIG. 1, and FIG. 3 is a diagram showing a torque curve of the conventional rotary compressor. FIG. 4 is a diagram corresponding to FIG. 2 showing one embodiment of the present invention, FIG. 5 is an explanatory diagram for explaining the action of the present invention, and FIG. 6 is a diagram for explaining the effect of the present invention. It is a diagram. Cylinder...2, Rotor...5, Blade...
6. Balance piston...101.

Claims (1)

[Claims] 1 A cylinder having a cylindrical inner wall surface, a rotor whose center rotates eccentrically around the center of the cylinder and whose outer periphery rolls while contacting the inner wall surface of the cylinder, and whose tip is in pressure contact with the outer periphery of the rotor. In a rotary compressor, the rotary compressor is equipped with a blade that retracts and retracts from the cylinder to separate the cylinder into a compression chamber and a suction chamber, and the rotary compressor is arranged within a range of 135° ± 90° from the position of the blade as measured along the rotational direction of the rotor. A rotary compressor comprising a balance piston that presses the rotor in contact with the outer peripheral surface of the rotor.