JPS62195481A - Nonlubricating type screw fluid mechinery - Google Patents

Abstract

PURPOSE:To permit the noncontact operation by detecting the existence of the contact between the both rotors by an AE sensor or an accelerating speed sensor which is arranged in a bearing part or in a casing close to the bearing part and controlling the speed of revolution of a motor on a female screw rotor side. CONSTITUTION:When male and female rotors 1 and 2 contact, the signal supplied from an AE sensor or an accelerating speed sensor 19 which is arranged in a bearing 6 part contains the pulse-shaped wave forms. Acontact detector 20 wave-detection-treats the signals, and the frequency distribution of the contact for the male rotor revolution angle thetaM is prepared. The result is taken into a calculator 21 together with the signals thetaM supplied from the revolution angle detectors 14 and 15 for the male and female rotors 1 and 2. The calculator 21 calculates the variation of revolution theta from thetaF and thetaM, and compares said variation with the contact frequency distribution, and determines the revolution speed control quantity for preventing the contact of the both rotors 1 and 2. The revolution speed control quantity is sent into the driving controller 18 for a motor, and the revolution speed of a motor 12 for the female rotor is controlled, and the noncontact operation of the both rotors 1 and 2 is permitted.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an oil-free screw fluid machine, and in particular, to
This relates to a drive system that rotates synchronously.

[Background of the invention]

Unlike oil-lubricated machines, non-lubricated screw fluid machines completely prevent contact between the male screw rotors, so torque is not transmitted directly between the rotors, as shown in Japanese Utility Model Application Publication No. 58-47273, for example. , is configured to be performed by a synchronous gear mounted on the shaft end.

Although this method is simple and requires only one set of synchronous gears, it is necessary to properly balance the machining precision of the male and female screw rotors, the gap between the teeth, and the machining precision of the gears.

However, in reality, during operation, there are complicated behaviors such as thermal deformation of the male and female screw rotors and elastic deformation of the gears, and there are problems such as the male and female screw rotors coming into contact with each other without achieving the originally set state. Ta. Although it is possible to set the shape and machining accuracy of the synchronous gear by taking such complicated behavior into consideration in advance, such work is generally difficult and impractical.

[Purpose of the invention]

An object of the present invention is to provide an oil-free screw fluid machine in which the male and female screw rotors can be driven synchronously without being in contact with each other, regardless of the machining accuracy, assembly accuracy, deformation during operation, etc. of the male and female screw rotors.

[Summary of the invention]

The present invention installs electric motors for driving male and female screw rotors, and controls the rotational speed of the electric motor of the female rotor so that the female screw rotor does not come into contact with the male screw rotor. The control method for the rotational speed of the electric motor of the female screw rotor is based on the quasi-static rotational transmission error of the female screw rotor measured quasi-statically with the male and female screw rotors assembled and the respective differences between the male and female screw rotors during operation. The rotation fluctuation of the female screw rotor calculated from the rotation angle is compared, and the method is such that the rotation fluctuation is the sum of the quasi-static rotation transmission error and the gap between the male and female screw rotor teeth that must be maintained during operation. Alternatively, the present invention has a feature of preventing contact from occurring by detecting the presence or absence of contact between the two rotors using an AE sensor or an acceleration sensor installed in a bearing section that supports the male screw rotor or the female screw rotor.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIG. The male screw rotor 1 (hereinafter referred to as the male rotor) and the female screw rotor 2 (hereinafter referred to as the female rotor) are equipped with bearings 6, 7.8, and the female rotor 2 so as to maintain a predetermined gap between the teeth. It is supported by bearings 9.10°11. Of these bearings, bearings 7 and 8 and bearings 10 and 11 support the respective rotors in the radial direction, and bearings 6 and 9 restrain the axial movement of both rotors. A rotor 3 of an electric motor is fitted on a shaft extending to one end of the male rotor 1, and a stator 4 is set on the stationary side opposite to this. Similarly to the male rotor 1, a rotor 12 of the electric motor is fitted to one end of the female rotor 2, and a corresponding stator 13 is provided. In this embodiment, a closed type case in which these elements are housed in a casing 5 is shown.

Rotor rotation angle detectors 14 and 15 are provided at the shaft ends of the female and male rotors. Externally, the casing 5 includes a rotation angle signal converter 16, a comparison calculator 17 that compares the rotation angle signal with a set value and performs a predetermined calculation, and controls the rotational speed of the motor according to the output signal from the comparison calculator 17. A split U system including a motor drive controller 18 is formed.

Next, the operation of this embodiment will be explained. Before operating this fluid machine, the male rotor 1 is rotated quasi-statically, and the rotation angle of the female rotor 2 is measured. The rotation angle of the male rotor 1 is 09, and the rotation angle of the female rotor is θIF. If the rotation speed ratio of the female rotor 2 and the male rotor 1 is n, then the rotation speed of the female rotor 2 in the ideal state is θF = n ~ ・・・・・・・・・・・・・・・・・・・
・・・・・・・・・・・・・・・・・・(1)

However, in reality, equation (1) does not completely hold due to processing errors and assembly errors of both rotors, and the rotation angle of female rotor 2 is Δ'θ, ) 3% n flM .・・・
−・・・・・・・・・・・・・・・(2) Has a large error. This Δθ. is called the quasi-static rotational transmission error of the female rotor, and shows a change as shown in Part 2 (a).

The comparator 17 has a storage section in which the waveform shown in FIG. 2(a) is stored. Further, the comparator is also stored with a rotation angle θg in terms of the female rotor, which corresponds to the set gap between the teeth of the male rotor and the sleeve rotor.

Next, the operation during operation will be explained. Although not specifically shown in FIG. 1, the male rotor IV'i is operated at a predetermined rotational speed by an electric motor constituted by a rotor 3 and a stator 4 in a generally well-known manner. From the rotation angle detector 14 provided on the male rotor 1 and female rotor 2, θ 1
A signal of 5 and θ is generated. θ2. When θ is expressed in the form of rotational speed with respect to time VC, it becomes as shown in Fig. 2).

θ9 and θ.

The signal is inputted to the signal converter 16, and the variable average rotational speed and variable rotational speed Δθ of the female rotor 2 are calculated as shown in the following equation.

Old = nshi 900091180180110111.
1901039166811008. (3)F
M Δθ=θF n−・・・・・・・・・・・・・・・・
(4) Here, 9 is the average rotational speed or set rotational speed of the male rotor 1. Δθ should have a waveform similar to ΔOo, as shown in FIG. 2(C). 9 and Δθ defined by equations (3) and (4)
is output from the converter 16 and input to the comparator +7vc. The comparison calculator 17 compares the quasi-static rotational transmission error Δθ0 that has already been stored and the input variable rotation angle Δ0, and calculates Δφ=Δθ−(Δθ0+θg)・Kawa...Shou...(5) A value is calculated for each θMVC. Δφ is also outputted from the comparator 17 and inputted to the motor drive controller 18 . The other of the two signals input to the electric drive controller 18, θ, is used to command the average rotational speed of the motor rotor 12, and the rotational speed is finely adjusted so that Δφ becomes zero.

Through the above series of operations, the female rotor can be rotated with a predetermined gap maintained between the two-coated male rotor 1 and the teeth. Machining errors and assembly errors between male and female rotors are expressed as quasi-static rotation transmission errors that are measured before operation, and during operation, the rotation angle is adjusted to correspond to this quasi-static rotation transmission error. It becomes harmless. therefore,
Unlike the synchronous gear system, it is no longer possible to arrange male and female rotors and synchronous gears to increase the processing accuracy and assembly accuracy. Furthermore, since the gap between the male and female rotors can be narrowed, performance can be easily improved.

FIG. 3 shows another embodiment of the invention. The same parts as in the embodiment of FIG. 1 are designated by the same reference numerals.

In this embodiment, the HlAh sensor or acceleration sensor 19 is arranged in the bearing part or in the casing near it.

A contact detector 20 analyzes the signal from the sensor 9 and detects the presence or absence of contact between the male and female rotors. 21V'i This is a computing unit that receives signals from the contact detector 20 and the rotation angle detectors 14 and 15, and sends a control signal to the motor drive controller 18 to prevent the male and female rotors from coming into contact.

The signals from the 19 AE sensors or acceleration sensors include
When the male and female rotors come into contact, a pulse-like waveform as shown in FIG. 4(a)K is included. This signal is transferred to the contact detector 20.
Now, processing such as detection is performed to create a frequency distribution of contact with respect to the male rotor rotation angle θMVC, as shown in FIG. 4(b) vc. This result indicates that the rotation angle detector 14 for the female rotor and the rotation angle detector 15 for the male rotor have a signal of 0.
and θ9 are input into the arithmetic unit 21. Arithmetic unit 2
1, θ.

From 09 to
By calculating this and comparing it with the contact frequency distribution, the number of rotational speeds at which the female rotor and male rotor should not come into contact can be determined.
Determine the amount. The rotational speed control amount determined in this way is sent to the motor drive controller 18 to control the rotational speed of the female rotor motor rotor 12.

In this embodiment, since the presence or absence of contact between the male and female rotors that may occur during operation is directly detected and controlled, even if the male and female rotors are deformed due to heat or fluid force and the shape of the rotor differs from that when it is at rest, The advantage is that there is no problem. Therefore, by using this embodiment together with the embodiment shown in FIG. 1, non-contact operation of the male and female rotors as actually marked becomes possible.

! In both the embodiments in Figures 1 and 3, all the components are housed within the casing. Although a closed type is illustrated, the electric motor does not need to be integrated with the female rotor or the male rotor, and may have a so-called open type structure in which it is disposed outside the casing.

Furthermore, although the electric motor attached to the female rotor is oriented in the opposite direction to the electric motor of the male rotor in the illustrated embodiment, it may be oriented in the same direction. In general, in screw fluid machines, the torque required to drive the female rotor may be several times lower than that of the male rotor, and the electric motor for the female rotor is expected to be smaller than that for the male rotor, so both male and female rotors are connected. It would be possible to place them on the same side.

〔Effect of the invention〕

As explained above, according to the present invention, there is no need for a synchronous gear, and contact between male and female rotors that depends on processing errors, assembly errors, and deformation of the synchronous gear does not occur, making it easy to operate a screw fluid machine without oil. becomes.

In addition, since the system maintains the gap between the teeth of both rotors when the male and female rotors are actually combined, the gap can be reduced, improving fluid performance. Furthermore, since the rotational speed of the female rotor can be controlled in consideration of machining errors, assembly errors, and deformations of the male and female rotors, there is no need to increase the machining accuracy and assembly accuracy of both rotors, and the machining and assembly process can be simplified. have

[Brief explanation of drawings]

Fig. 1 is a diagram showing the structure of the screw fluid machine and the control system according to an embodiment of the present invention, and Fig. 2 is a diagram showing the quasi-static rotation transmission error, rotation speed, and control system obtained in a non-embodiment. FIG. 3 is a configuration diagram of a control system of a screw fluid machine showing another embodiment. FIG. 4 is an explanatory diagram of sensor waveforms and frequency patterns obtained in the embodiment of FIG. 3. be. 1... Male rotor 2... Female rotor 3, 12.
...Electric motor rotor 4, 13...Electric motor stator 5
...Casing 6, 7.8, 9.10. II...
・Bearing 14.15...Rotation angle detector 16...
- Converter 17... Comparison calculator 18... Motor drive suppressor 19... AE sensor or acceleration sensor 20... Contact detector 21... Arithmetic unit.

Claims (1)

[Claims] 1. In a screw fluid machine in which a male screw rotor and a female screw rotor that mesh with each other are housed in a casing and both ends of both rotors are supported by bearings, an electric motor is connected to the male screw rotor. An oil-free screw fluid machine characterized in that a separate electric motor is also arranged on the axis of the female screw rotor, and the male and female rotors are driven synchronously through both electric motors. 2. The rotational fluctuation of the female screw rotor calculated from the quasi-static rotation transmission error of the female screw rotor measured quasi-statically with the male screw rotor and female screw rotor assembled and the rotation angle of both rotors during operation. A patent characterized in that the rotational speed of the electric motor on the female screw rotor side is controlled so that the rotational fluctuation is the sum of the quasi-static rotational transmission error and the required gap between the two rotor meshes. An oil-free screw fluid machine according to claim 1. 3. The AE sensor or acceleration sensor installed on the bearing that supports the male screw rotor or female screw rotor detects whether or not there is contact between the two rotors, and controls the rotational speed of the electric motor on the female screw rotor side to prevent contact. An oil-free screw fluid machine according to claim 1, characterized in that the oil-free screw fluid machine is configured to: