JPS60125790A - Vibration-damping device for electric compressor - Google Patents

Abstract

PURPOSE:To prevent abnormal noise, breakage or the like by a method wherein the rotating frequency of a motor is increased or decreased when the value of vibration, detected by a vibration detecting device provided on the case of the compressor, the wiring of connection or the like, has exceeded the preset value of abnormal vibration. CONSTITUTION:A rotating frequency changing device E inputs the values delta of vibrations, detected by vibration detecting devices 15, 16 mounted on the case 12 of the motor compressor 13 and the pipeline for connection 6 respectively. In case either one of the values delta of vibration has exceeded the preset abnormal vibration value deltam and is continued for a time longer than a predetermined period of time (t), a signal is outputted to a speed signal circuit, not shown in the diagram, under operating as follows: the rotating frequency changing device E outputs a changing command to a speed signal circuit so that the rotating frequency is increased by S than a resonance area D in an air-conditioning machine when a room temperature T is lower than a set temperature Tm. In case the room temperature T is higher than the preset temperature Tm, the circuit functions reversely. According to this method, abnormal noise, breakage or the like, due to the resonance phenomena of the compressor 13 itself, connecting pipeline 6 or the like, may be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a vibration isolating device for an electric compressor, and particularly to an electric compressor of a type in which the power frequency of the electric motor is controlled over a wide range by an inverter or the like.

(B) Prior art In the past, various air conditioners and the like have been devised in which the power frequency of the electric motor, which is the drive unit, is widely controlled using an inverter, etc. in order to widely control the capacity of the electric compressor. There is.

However, most of them do not take any measures to reduce the vibration of the electric compressor itself. Here, there is Japanese Patent Application Laid-open No. 147510/1984 as a method that deals with vibration reduction, although it is small. As shown in Figure 1, this consists of a cylinder (1), an upper bearing (2), and a lower bearing (3).
A piston (5) rotatably moved by a rotating shaft (4) is provided in a space surrounded by a piston (5), sucks refrigerant gas through a connecting pipe (6), compresses the refrigerant gas with the piston (5), and discharges the gas through a discharge valve (7). A compressor part (8) that discharges more air, a rotor (9) and a stator a connected to this compressor part by a rotating shaft (4)
0 and has an electric motor section αυ that drives the compressor section (8), and the compressor section (8) and the electric motor section αυ are provided in a sealed housing α2,
It consists of The rotating shaft (4) is cantilevered by an upper bearing (2). On the other hand, the motor section αυ is composed of a four-pole induction motor, and the height of the coil end 04) of the stator QOI is made small.

With this configuration, the space between the upper bearing (2) and the stator (10) can be reduced, and the space between the upper bearing (2) and the stator (10) can be reduced.
The resonant frequency of the rotary shaft (4) is made higher than before by bringing the rotary shaft (4) closer to the stator (00).As a result, even if the electric compressor (03) is driven at high speed, (4) The resonant frequency can be set to a sufficiently high value, and an electric compressor with low vibration and noise is provided.

However, in such a configuration, the rotating shaft (4)
There is a limit to increasing the resonant frequency of compressor 03.
) When attempting to control the power supply frequency of the motor over a wider range in order to further improve its performance, there was a problem in that it became impossible to follow the power supply frequency, and the desired vibration damping effect could not be obtained. Moreover, the one-self configuration only reduces the vibration of the compressor α3) itself, and does not take any measures against the resonance of the connecting pipe (6), etc. of this compressor. In other words, in the process where the power supply frequency of the motor changes over a wide range, when a frequency that is an integral multiple of the rotational frequency of the motor matches the natural frequency of the connecting pipe (6), the connecting pipe (6) causes a resonance phenomenon. However, there was a problem in that there was a risk of damage due to abnormal vibrations and abnormal noise was generated. This is a compressor (
The same can be said of the vibration system of the 131 itself.

(]→ Purpose of the Invention The present invention has been made in view of the above, and its purpose is to prevent changes in the power supply frequency in an electric compressor that uses an inverter etc. to widely control the power supply frequency of the motor. When a frequency that is an integral multiple of the motor's rotational frequency matches the natural frequency of the compressor's vibration system or connecting piping, etc., the compressor is prevented from continuing to operate in this matched state, and the compressor is This is to prevent resonance phenomena in the compressor itself and connecting pipes, etc., and to prevent damage caused by abnormal noise of the compressor itself and abnormal vibrations of the connecting pipes.

B) Structure of the Invention The structure of the present invention is an electric compressor in which the power frequency of the motor is widely controlled by an inverter or the like, and an imaging detection device provided in the case of the compressor or the connecting piping, etc. The device is equipped with means for increasing or decreasing the rotational frequency of the electric motor when the vibration value detected by the device exceeds a preset abnormal vibration value, and in the process of changing the power supply frequency, the rotational frequency of the electric motor is increased or decreased. This is to prevent the compressor from continuing to operate in a condition where the frequency that is an integral multiple of the frequency matches the natural frequency of the vibration system of the compressor or the connecting piping.

(e) Examples Embodiments of the present invention will be described below based on the drawings.

03) is an electric compressor having a connecting pipe (6). As shown in FIG. 3, this electric compressor has a power supply frequency of the electric motor αυ controlled over a wide range by a power supply circuit (8) including an inverter control circuit (II), and has a wide range of capabilities. To explain below, ■) is the power source a, and 6
diodes (D,) (珈G),) CI),)
This is a rectifier circuit composed of a CD, ) (river), a cheek coil (CHI), and a capacitor (C1). This rectifier circuit converts AC power input from the power source into DC power. (Q is a Cheetuba circuit composed of a transistor (Ti1), a check coil (CH2), and a capacitor (C7). This Cheetuba circuit converts the voltage of the DC power source obtained from the rectifier circuit). It is controlled by a transistor (T□) and is connected to a cheek coil (CH2).
') and a capacitor (C,).

Here, the transistor (TRI) is the speed signal circuit CF
) The speed signal generated in the chipper control circuit (Gl
It is driven by the input via. ■) is 6 transistors (T, 2) (TR3) (T, 4)
(TR5) ('r-a) This is an inverter circuit configured by using ('ray) as a bridge. This inverter circuit is a chishutsuba circuit (DC power smoothed by q is input to the inverter control circuit 0, a frequency corresponding to the DC voltage is generated, and then the transistor (T-v) (Till)
(TRI4) (Ttomi) (TR6) ('r+t'r
) is driven to vary the power supply frequency over a wide range, and then power is supplied to the motor section (11).

Therefore, (19 and σe are the case of the 0th floor of the electric compressor (1
2 and a vibration detection device attached to the connecting pipe (6).

(G) is a rotational frequency changing device, and this device inputs each of the vibration values δ detected by the vibration detection device α51α0, and any of these vibration values δ is a preset abnormal vibration value δm. If it continues for a predetermined time or more, it operates as explained below and outputs it to the speed signal circuit ().In other words, in an air conditioner, etc., when the room temperature T is lower than the set temperature Tm. The speed signal circuit (if an acceleration command is issued to 0, the rotation frequency changing device) sends a change command to the speed signal circuit (F) to increase the rotation frequency by S above the resonance region. Output.Also,
When the room temperature T is higher than the set temperature Tm and a deceleration command is issued to the speed signal circuit (Fl), the rotational frequency changing device (E) changes the rotational frequency from the resonance region to S.
A change command for lowering the speed by a certain amount is output to the speed signal circuit (F). As a result, a frequency that is an integral multiple of the rotational frequency of the motor circle is transmitted to the vibration system of the compressor (13) or the connecting pipe (6).
) etc., the electric motor unit is prevented from operating in a resonance region that substantially coincides with the natural frequency. Incidentally, in order to further reduce the resonance phenomenon, a more stable effect can be obtained by increasing the change amount S within the permissible limit.

(f) Effects of the Invention As described above, the present invention provides an electric compressor in which the power frequency of the motor is controlled over a wide range using an inverter or the like.
A vibration detection device installed in the case or connecting piping of the compressor, and means for increasing or decreasing the rotational frequency of the electric motor when the vibration value detected by this device exceeds a preset abnormal vibration value. Therefore, in the process of changing the power supply frequency, a frequency that is an integral multiple of the rotational frequency of the motor matches the natural frequency of the vibration system of the compressor or the connecting piping, etc., and the motor moves within their resonance region. This prevents abnormal noise, damage, etc. due to resonance phenomena of the compressor itself, connecting pipes, etc.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of an electric compressor showing a conventional example, FIGS. 2 to 5 show an embodiment of the present invention, FIG. 2 is a longitudinal sectional view of an electric compressor, and FIG. 3 is an inverter. A control circuit diagram including the circuit, FIG. 4 is an explanatory diagram showing the operation of the rotation frequency correction device,
FIG. 5 is a 7r:I chart showing the operating state of the compressor. (6)... Connection piping, (11)... Electric motor section,
(12+... sealed case, 0th floor... electric compressor,
(15)Q6)...Vibration detection device, E...Rotation frequency correction device. Figure 1 Figure 4 σepc) Figure 5

Claims (1)

[Claims] (1) In an electric compressor in which the power frequency of the motor is widely controlled by an inverter, etc., a vibration detection device installed in the compressor case or connecting piping, etc., and the vibration value detected by this device are set in advance. A vibration isolating device for an electric compressor, comprising means for increasing or decreasing the rotational frequency of the electric motor when an abnormal vibration value is exceeded.