JP2000028489A - Apparatus for measuring spring constant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a correct measured value of a superior reproducibility of a spring constant by mechanizing a sequence of operations for measuring the spring constant of a spring. SOLUTION: This measuring apparatus has a frame 2 suspending down and holding a spring 6 from an upper end. A movable table 8 slides along two guide rods 7 of the frame 2. The movable table 8 moves up and down by the rotation of a screw shaft 10 driven by a driving device 15. A load sensor 11 is set to the movable table 8, and a length-measuring machine for reading a scale recorded at a magnetic scale 16 and for measuring a length of the spring 6 is set to the frame 2. A control apparatus 21 compares an actual load signal and an actual length signal with a set load and a set length (or set elongation amount), judges whether or not the spring 6 is required to be elongated and outputs an action command to the driving device 15 or an operation command to an operation device 23 in accordance with the judgment result.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spring constant measuring device used for measuring a spring constant of a spring supporting a seal ring for a shaft seal of a generator using hydrogen gas as a cooling medium.

[0002]

2. Description of the Related Art A turbine generator in which hydrogen gas as a cooling medium is sealed is provided with a shaft seal mechanism for suppressing leakage of hydrogen gas from a bearing portion. In this shaft seal mechanism, a seal ring in contact with the rotor bearing is supported by two vertically arranged springs so that an appropriate oil film is maintained while following a minute displacement of the rotor. Has become. Each time the rotor is displaced, a load is applied to this spring via the seal ring.If the spring is used for a long period of time, the deterioration will progress, and the initial spring constant secured at the time of manufacturing the spring will be weakened and the spring will function properly. May be gone. For this reason, in the periodic inspection of the generator, the spring constant of the spring removed from the generator is measured to evaluate whether the spring is sound or not.

Usually, in the measurement of the spring constant, the actual additional load when the spring is extended to the set load is divided by the value obtained by subtracting the free spring length from the spring length at the actual additional load, that is, the amount of extension of the spring. Seeking in a way.

[0004] In this operation, first, the spring is placed sideways, and the free length of the spring is measured using a caliper.
Next, one end of the spring is fixed, a spring weigher is arranged at the other end, and the spring weigher is manually pulled to extend the spring to a set load, and the actual additional load amount at this time is read from a scale. Further, the procedure is carried out by measuring the length of the spring at the time of the actual applied load using calipers, and calculating the spring constant by manual calculation based on the obtained values. Here, all operations such as recording and calculation of measured values are performed manually.

[0005]

In the above-described conventional measurement of the spring constant, which is performed manually, it is necessary to prevent the inspector from arbitrarily making judgments in each stage of the process, thereby avoiding large variations in the measurement results. I can't. In addition, when priority is given to making a more careful judgment, extra work is involved due to redo, etc., and the work cannot be performed efficiently.

[0006] Even if we try to measure the spring constant without error,
As long as human intervention is involved, there is a limit and it is often difficult to obtain accurate measurement values, and mechanization of the measurement is required.

[0007] An object of the present invention is to mechanize a series of operations indispensable for measuring the spring constant of a spring, so that operations can be performed with excellent reproducibility and high efficiency.
Moreover, it is an object of the present invention to provide a spring constant measuring device capable of obtaining an accurate measured value of the spring constant.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a base, a frame which is provided upright on the base and suspends and holds a spring for measuring from an upper end to a lower part. Two guide rods arranged side by side at substantially the same distance from the center of the table, a movable table having a table nut slidably provided along the guide rods, and a table below the movable table A screw shaft that is screwed with the nut and moves the movable table by rotation of the nut, a drive device that drives the screw shaft, and the other end of the spring that is on the upper surface of the movable table and that follows the operation of the movable table , A load detector that detects the load applied to the spring, and provided over the length that the spring extends along the frame Is a length measuring device for measuring the length of the spring, and a load output device for outputting an actual load signal on the basis of the detected load of the spring applied from the load detector,
A length measuring device output device that outputs a real length signal based on a detected length of a spring given from a length measuring device, and compares a given actual load signal and a given actual length signal with a set load and a set length. A controller that determines whether or not the spring needs to be extended and outputs an operation command to the drive device or a calculation command to a calculation device that calculates a spring constant in accordance with the determination result.

In the spring constant measuring device having the above-mentioned structure, when the actual load signal given from the load output device reaches a set load, the actual length signal from the length measuring device output device is used for the free length of the spring. Is given from the control unit to the arithmetic unit as a value representing the free length of.

When the actual load signal and the actual length signal provided from the load output device and the length measuring device output device extend to the set load and the set length, the length of the spring at the time of extension is determined. The actual load signal and the actual length signal are provided from the control device to the arithmetic device. An arithmetic command is output to the arithmetic device at the same time, and the spring constant is automatically calculated there.

As a result, a measuring device having excellent reproducibility in measuring the spring constant can be obtained. In addition, it is possible to work with high efficiency. In addition, accurate spring constant measurements can be obtained.

Further, in the present invention, preferably, the guide rod includes an upper limit switch and a lower limit switch near an upper end and a lower end thereof.

[0013] In the above structure, when the movable table is moved up or down to the position where each limit switch is installed, the driving device can be stopped reliably, and a malfunction of the driving device may occur due to the failure of the driving device. Also, it is possible to shut down the measuring device before a serious accident occurs.

Further, the present invention preferably includes a cylindrical guide sleeve extending over the entire length of the spring on the upper surface of the movable table.

[0015] In the above structure, even if the spring used for a long time is deformed, the deformation can be corrected by surrounding the guide sleeve, and the spring can be correctly oriented in the direction of applying the load. Thus, the spring constant can be accurately measured.

The present invention preferably includes a level on the upper surface of the movable table.

In the above-mentioned structure, when an inclination of the arrangement of the movable table is found by the inspection with the level, the horizontal of the movable table is adjusted by adjusting the height of the plurality of adjusting bolts of the base. It is possible to put out.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, the spring constant measuring device includes a box-shaped base 1 and a frame 2 provided upright on the upper surface of the base 1. The base 1 has four casters 3 and four adjustment bolts 4 on the lower surface.
In the drawing, only two of the four casters 3 and the four adjustment bolts 4 are shown. Further, a driving device including a motor described later is provided inside the base 1.

Further, the frame 2 standing upright on the upper surface of the base 1 has a fixed hook 5 attached downward from the upper end thereof. At the time of measuring the spring constant, the spring 6 is supported with one end thereof hooked on the fixed hook 5 and the other end hooked on the movable hook described later. Also, frame 2
The two guide rods 7 are provided at substantially the same distance from the center of the guide rod. Further, a movable table 8 supported by a guide rod 7 in a direction crossing the frame 2 is provided. The movable table 8 is configured to move up and down while sliding along two guide rods 7 by rotation of a screw shaft described later.

The movable table 8 has a table nut 9 at the center thereof, and a male screw of a screw shaft 10 is screwed into the screw to be cut into the table nut 9. Therefore, when the screw shaft 10 rotates clockwise, the movable table 8 moves upward via the table nut 9, and when it rotates counterclockwise, it moves downward.

Further, the movable table 8 is provided with a load sensor 11 on the upper surface for detecting a load applied to the spring 6 by measuring a spring constant. This load sensor 11
Movable hook 1 that hooks the other end of spring 6 according to
2 are installed. The load sensor 11 outputs the detected load value as a load signal one by one.
And a signal transmission path.

A cylindrical guide sleeve 14 for correcting the deformation of the spring 6 is provided on the upper surface of the movable table 8 over the entire area in the longitudinal direction of the spring 6. Further, the screw shaft 10 is connected to a driving device 15 including a motor in the base 1. The driving device 15 is connected to a controller described later by a signal transmission path.

The driving device 15 connected to the screw shaft 10 is connected to the screw shaft 1 while the motor rotates.
When the movable table 8 is moved to the set position while rotating the 0 clockwise or counterclockwise, the motor stops and the movable table 8 is held at that position. Further, by controlling the rotation speed of the driving device 15, the movable table 8 can be moved at a high speed to near the set position, and can be moved at a low speed from there.

A magnetic scale 16 on which magnetic graduations are recorded is provided along the inner surface of the upright frame 2. Further, the movable table 8 is provided with a displacement sensor 17 provided with a read head for reading a magnetic scale on the magnetic scale 16 so as to face the magnetic scale 16. The displacement sensor 17 is connected by a signal transmission path to a length measuring device output device 18 that outputs a displacement amount (length of the spring 6) read by the reading head as a length signal.

On the other hand, the two guide rods 7 have an upper limit switch 19 near their upper ends and a lower limit switch 20 near their lower ends. The upper limit switch 19 and the lower limit switch 20 are connected to a control device described later by a signal transmission path.

Further, the spring constant measuring device is provided with a control device 21 for extending the spring 6 in accordance with the operation command and for giving the amount of expansion and the like to a later-described arithmetic device in accordance with the calculation command to calculate the spring constant. The control device 21 receives a command given according to a sequence, and is connected to a controller 22 for rotating the drive device 15 by a signal transmission path. Further, it is connected to an arithmetic unit 23 for calculating a spring constant based on the given load signal and length signal by a signal transmission path.

Further, a level 24 is provided on the upper surface of the movable table 8 to check that the arrangement of the movable table 8 is horizontal when the movable table 8 is used.

On the other hand, FIG. 2 shows each function of the control device 21 by a block. The input unit 25 is a load output device 13
And the length signal from the displacement output device 18 are input to the comparison / determination unit 26. The comparison determination unit 26 compares the input load signal and length signal with the set load and set length stored in the storage unit 27, and outputs each command according to the comparison result. That is, by comparison,
When it is determined that the spring 8 needs to be further extended, an operation command is output to the operation output unit 28. On the other hand, when it is determined that the spring 8 does not need to be extended any more, an operation instruction is given to the operation output unit 29.

The storage unit 27 stores the load when measuring the free length of the spring 6, the load when the spring 6 is set to be extended, and the length to be extended when the set load is applied. are doing.

The present embodiment has the above-described configuration, and when measuring the spring constant, the spring 6 is attached to the fixed hook 5.
Is given by the controller 21 to give a start command, the driving device 15 is rotated by the command given to the controller 22, and the movable table 8 is moved to a position where the movable hook 12 can hold the spring 6. Further, when the movable table 8 is moved by a command given to the controller 22 and the load signal given from the load output device 13 reaches a set load for measuring the free length of the spring 6, the length measuring device output device 1
The length signal from 8 is given to the arithmetic unit 23 as the free length of the spring 6.

Further, the movable table 8 moves at a high speed near a set position at which the movable table 8 extends to a set load and a set length according to a command from the control device 21, and moves at a low speed from there.
When the load signal and the length signal from the load output device 13 and the length measuring device output device 18 extend to the set load and the set length when the spring 6 is extended, the load signal and the length measurement from the load output device 13 are obtained. The length signal from the output unit 18 is supplied to the arithmetic unit 23. At the same time, a control command is output from the control device 21 to the calculation device 23, and the calculation device 23 automatically calculates the spring constant as described later. Thereafter, the movable table 8 returns to the set load position where the free length of the spring 6 is measured by a command from the control device 21.

On the other hand, when a calculation command is given, the calculation device 23 calculates a spring constant as follows. One is a method based on a load standard, in which the actual additional load when the spring 6 extends to the set load is calculated by subtracting the free length from the length of the spring 6 when the actual additional load is applied, ie, the amount of extension of the spring 6. , Calculate the spring constant. In another calculation method based on the amount of elongation, the actual additional load when the spring 6 extends to the set amount of elongation is divided by the actual amount of elongation to calculate a spring constant.

During this series of work, for some reason,
For example, when the drive device 15 becomes uncontrollable due to a failure of the controller 22 and the movable table 8 performs an abnormal operation, the movable table 8 can be moved to the upper limit switch 19 if it is moving up, or to the lower limit switch 20 if it is moving down. When the table 8 contacts, the emergency stop device of the control device 21 operates, and the drive device 15 can be stopped.

Further, since the spring 6 is bent and deformed over a long period of use, the deformation of the spring 6 is corrected by the cylindrical guide sleeve 14 extending over the entire area of the spring 6, and the spring 6 is straightened. Measure. This allows the spring 6 to be correctly oriented in the direction in which the load is applied, so that the spring constant can be accurately measured.

Further, while observing the inclination of the movable table 8 with the level 24 provided on the upper surface of the movable table 8, it is possible to adjust the height of the four adjustment bolts 4 to accurately level the movable table 8. it can.

As described above, in the present embodiment, the length and load of the spring 6 are measured in accordance with the sequence, the movable table 8 is moved to the set position based on the measured values, and the spring constant is automatically calculated. It becomes possible to do. This makes it possible to obtain a measuring device with excellent reproducibility. In addition, it is possible to work with high efficiency. Further, a more accurate spring constant measurement value can be obtained as compared with a manual operation.

[0037]

As described above, according to the present invention, the length and load of the spring are measured in accordance with the sequence, and the movable table is moved to the set position based on the measured values.
It is possible to automatically calculate the spring constant, and it is possible to obtain a measuring device excellent in reproducibility. Further, it is possible to work with high efficiency. Further, a more accurate spring constant measurement value can be obtained as compared with a manual operation.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an embodiment of a spring constant measuring device according to the present invention.

FIG. 2 is a functional block diagram showing details of a control device shown in FIG. 1;

[Explanation of symbols]

 2 frame 6 spring 8 movable table 10 screw shaft 11 load sensor 13 load output device 15 drive device 16 magnetic scale 18 length measuring device output device 21 control device 23 arithmetic device

Claims (4)

[Claims] 1. A base, a frame provided upright on the base, and suspending and holding a spring for measuring from an upper end to a lower part, and two frames arranged substantially equidistant from the center of the frame. A guide rod, a movable table provided slidably along the guide rod, and having a table nut; and a lower portion of the movable table, which is screwed with the table nut, and the movable table is rotated by rotation of the movable table. A screw shaft for operating the screw shaft, a driving device for driving the screw shaft, and holding the other end of the spring on the upper surface of the movable table,
A load detector for detecting a load applied to the spring while following the operation of the movable table; and a length measuring device provided over a length of the spring extending along the frame to measure the length of the spring. A load output device that outputs an actual load signal based on the detected load of the spring given from the load detector, and outputs an actual length signal based on the detected length of the spring given from the length measuring device. Length measuring device output device, the given actual load signal and actual length signal, and the set load and set length are compared to determine whether or not the spring needs to be extended, and the driving device according to the determination result. And a control device for outputting an operation command to the operation device for calculating the spring constant. 2. The guide rod includes an upper limit switch and a lower limit switch near an upper end and a lower end of the guide rod, and the movable table may move up or down to the installation position of the upper limit switch or the lower limit switch due to malfunction of the driving device. 2. The spring constant measuring device according to claim 1, wherein the driving device is stopped when the spring device is lowered. 3. The movable table is provided with a cylindrical guide sleeve extending over the entire area in the longitudinal direction of the spring on the upper surface of the movable table, and the guide sleeve corrects deformation caused by aging of the spring. The spring constant measuring device according to claim 1. 4. A level is provided on an upper surface of the movable table, and when a horizontal inspection with the level reveals an inclination in the arrangement of the movable table, the height of the plurality of adjustment bolts of the base is adjusted. 2. The spring constant measuring device according to claim 1, wherein the device is adjusted so as to be horizontal.