JPS6115590A - Vibration reducing unit of rotary compressor - Google Patents

Abstract

PURPOSE:To fundamentally and effectively reduce a vibration caused by the variation in a load torque by controlling to feed back to vary the torque generated in a motor in response to the twist of a rotary compressor. CONSTITUTION:Since the inverter 4 is controlled by control means 6 in response to the twisting vibration of a compressor 1 detected by vibration detecting means 5 to control the feed back so that power frequency (w) of a motor 2 during one revolution varies, a torque generated in response to the twisting vibration of the compressor 1 is applied to the motor 2, and the load torque during one revolution corresponds to the torque generated in the motor 2. Thus, the vibration can be largely reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application) The present invention relates to a vibration reduction device for reducing vibrations in a rotary compressor such as a rolling piston compressor, and particularly to a vibration reduction device for reducing vibrations caused by fluctuations in load torque of the rotary compressor. Regarding measures to reduce vibration.

(Prior Art) Generally, in a rotary compressor, since its dynamic balance is almost perfect, its vibrations are largely caused by load torque fluctuations. In other words, the rotation of the rotary compressor fluctuates due to variations in load torque, and the reaction force of this rotational fluctuation causes torsional vibration in the compressor. Therefore, once the type of rotary compressor is determined and the load torque fluctuation pattern is determined, approximately constant torsional vibration will occur accordingly.

Conventionally, as a countermeasure to reduce vibration caused by such a one-herk variation in load, for example, Japanese Patent Application Laid-Open No. 1986-
As disclosed in Japanese Patent No. 50244, the load can be reduced by installing several stages of dynamic vibration absorbers in the compressor container and making the first natural frequency of the dynamic vibration absorbers almost match the rotational frequency or power frequency of the compressor. Absorbs vibrations caused by torque fluctuations.
It is known what has been done so. It is also known to reduce vibrations caused by load torque fluctuations by increasing the moment of inertia of a rotary compressor and suppressing its rotational fluctuations.

(Problems to be Solved by the Invention) However, none of the conventional techniques has any drastic measures against vibrations caused by load torque fluctuations, and therefore there is a natural limit to vibration reduction. There is a problem that vibration reduction cannot be effectively achieved by 1 u.

Therefore, in order to investigate the vibration caused by the above-mentioned load torque fluctuation, the present inventor investigated the motion of the rotary compressor in the rotational direction, and found that the motion is expressed by the following equation.

Is ・(d 2 θ ?; , /(It
2)+c-d θS/dt 10k 3
・θ5−TL −T−M (
i) Here, Is: Moment of inertia of the compressor θS: Angular displacement in the rotational direction of the compressor C: Torsional damping constant of the compressor 1s: Torsional spring constant of the compressor T [: Load torque of the compressor TM: Motor Generated Torque In equation (1) above, assuming that the load torque TL of the compressor varies, in order to reduce the value on the right side and reduce the rotational fluctuation of the compressor, the motor generated torque TM is changed to the load torque. It can be seen that it is sufficient to vary it according to the variation of the sharpness. However, in the case of an induction motor, there is a gap between the electrical rotation angle and the mechanical rotation angle, so it is difficult to vary the motor-generated torque TM as a power source in response to variations in the load torque T. However, if the power supply frequency is finely controlled during -. rotation, the motor generated torque TM can be controlled.

From this, an object of the present invention is to change the power supply frequency during one rotation of the electric motor according to the torsional vibration of the rotary compressor, thereby making the torque generated by the electric motor correspond to fluctuations in the load torque. The objective is to fundamentally and effectively reduce vibrations caused by load torque fluctuations.

(Means for solving the problem) In order to achieve the above object, the solving means of the present invention is as follows:
As shown in the figure, an inverter (4) that controls the rotation speed of the electric motor (2) of the rotary compressor (1), and a vibration detector ru (5) that detects torsional vibration of the rotary compressor (1). , applicable]
h Receiving the output of the motion detection means (5), rotation compression tall
; - of the electric motor (2) in response to the torsional vibration of (1)
The inverter (4) is controlled by a control means (6) for controlling the inverter (4) so as to change the power supply frequency during rotation.

(Function) With the above configuration, in the present invention, the electric motor (2
) - By changing the power frequency during rotation, the electric motor is removed 2)
By changing the torque generated by the motor, it is possible to suppress the rotational compression (thick (1) rotational fluctuation, that is, the torsional vibration) by adjusting the load 1 - torque fluctuation to the motor generated torque fluctuation.

(Example) Hereinafter, an example of the present invention will be described based on the drawings from FIG. 2 onwards.

2 to 5 show an embodiment in which the present invention is applied to an L-ring piston compressor. 2) is an electric motor as a drive unit of the compressor (1), and (3) is an AC power source as a power source of the electric motor (2), and the AC power source (3) and the electric motor (2) An inverter (4) that controls the frequency of the electric motor (2) is interposed between the two.

On the other hand, (5> is the rotational vibration (d2θs) of the compressor (1)
/dt2) (that is, torsional vibration), the vibration detection means (5) is a control means (6) such as a microcomputer that controls the inverter (4). is connected to enable the transmission and reception of signals.

The control means (6) operates as shown in the flowchart of FIG. 3, and in the first step S1, the vibration detection means (6)
5) to compressed MM < -I) times ff',!
+ (d2θs/dt2) (torsional vibration) signal is input, and in step S2 this rotational vibration (12θs/
dt2), calculate the power supply frequency ω and power supply voltage V of the electric motor (2) so as to generate an increase in the generated torque ΔTM of the electric motor (2) that is proportional to the rotational vibration (d2θs/dt2), After that, in step S3, the power supply frequency ωd5 and the power supply voltage V are output to the inverter (4).
) according to the rotational vibration (d2 θS/dt2) of the electric flI
The inverter (4) is controlled so that the power supply frequency ω during rotation of the machine (2) changes.

Therefore, in response to the rotational vibration (d2θS/dt2) (torsional vibration) of the compressor 1) detected by the vibration detection means (5), the control means (6) controls the inverter (/l
) is controlled, and feedback control is performed so that the power supply frequency ω during rotation of the electric motor (2) changes.
The generated torque △TM (=-k ・(12θ3 , '+It'
, k: proportionality constant) is added to 4, so that 1 herk of load during rotation corresponds to 1 rk generated by the electric motor (2).

In other words, the above formula (1) is r s - d 2 θ s / clj' ten c-d
θS/ d t + k s ・06=T - (TM
18 M), and since △l'-M=-d2 θS/dt2, in the end, (Is+k)-d2 θs/dt2+c -d
θS/clt+ks−θ5=TL−TM
(F+), and if the proportionality constant k is made sufficiently large as shown in the above equation Oi), the moment of inertia of the upper compressor (1) appears to be large. Therefore, rotational fluctuations of the compressor (1) can be suppressed to a small level, and vibrations caused by load 1-lux fluctuations can be fundamentally and effectively reduced.

Now, specifically, by appropriately setting the feedback time constant and proportionality constant, the fluctuation of the rotational speed dθ,/dt of the crankshaft, which is the rotating part of the compressor (1), and the compressor
When we measured the rotational vibration θS in 1), we obtained results similar to those shown in Figures 4 and 5. In the example of the present invention with feedback control (shown by the solid line), the conventional example without feedback control (shown with the broken line). ) compared to the rotational speed dθ/
It can be seen that both the fluctuation of dt and the rotational vibration O8 can be suppressed to extremely small values, and the vibration can be significantly reduced.

In the above embodiment, the rolling piston type compression (type) was described, but the present invention can also be applied to various types of rotary compression (type) such as a slide-in-vane type, and similar effects can be obtained.

(Effects of the Invention) As explained above, according to the vibration reduction device for a rotary compressor of the present invention, feedback control is performed so that the motor generated torque is changed or decreased in accordance with the torsional vibration of the rotary compressor.
Since rotational fluctuations, that is, torsional vibrations of the rotary compressor can be suppressed, even in rotary compressors with large load torque fluctuations, it is possible to fundamentally and effectively reduce the vibrations caused by the load 1-lux fluctuations. Saru.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of the present invention, FIGS. 2 to 5 (51) show an embodiment of the invention, FIG. Flowchart 1- showing operation
Fig. 1 is a height test diagram showing fluctuations in rotational speed of the crankshaft and rotational vibration of compression history in Fig. 1 a3 and Fig. 5 (zL, respectively, compression). 1)...Compressor, (2)...Electric motor, (4)...
・Inverter, (5)...Vibration detection means, (6)...
- Control means.

Claims (1)

[Claims] (1) An inverter (4) that controls the rotation speed of the electric motor (2) of the rotary compressor (1), a vibration detection means (5) that detects torsional vibration of the rotary compressor (1), and the vibration detection means ( 5
control means (6) for controlling the inverter (4) so as to receive the output of the rotary compressor (1) and change the power frequency during one revolution of the electric motor (2) in response to the torsional vibration of the rotary compressor (1);
) A vibration reduction device for a rotary compressor.