JPH0629702Y2 - Magnetostrictive stress measuring device for cylindrical materials - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to a non-contact magnetostrictive stress measuring device for a cylindrical material such as a round bar or a tube.

[Prior Art] When bending stress or axial stress is applied to a steel pipe or the like, in order to know the distribution state of the stress, in the conventional case,
For example, the X-ray stress measurement method is used. In this X-ray stress measurement method, the crystal plane spacing is d, and when X-rays of wavelength λ are incident at an angle of θ with respect to that plane, when the direction of the diffracted X-rays is also θ, nλ = 2dsinθ Since there is a relationship of (n is a positive multiple), d can be obtained from this equation by measuring θ with an X-ray of which λ is known, and this is a measuring method of calculating stress from the change of d. .

However, in this X-ray stress measurement method, it is necessary to perform electrolytic polishing at the measurement position by pretreatment, and the pretreatment takes 30 minutes per point and the measurement time also takes about 10 minutes per point.
Moreover, in the case of steel pipes, it is necessary to measure at least 4 points in 90 ° increments in the circumferential direction, which requires a large amount of measurement time.
Further, since the operation is complicated, it is practically difficult to provide a large number of measurement points, and therefore the number of data obtained is naturally limited.

Therefore, it is conceivable to use a magnetostrictive stress measuring method that is simpler than the X-ray stress measuring method.

In this magnetostrictive stress measurement method, when a load is applied to a magnetic material, anisotropy occurs in the magnetic permeability, and the magnetic permeability in the load direction increases,
On the contrary, since the magnetic permeability in the direction perpendicular to the load direction becomes smaller,
This is a method of measuring the direction and magnitude of the principal stress by detecting the difference in both magnetic permeability with a magnetostrictive sensor having an exciting core and a detecting core. According to this measuring method, one measuring time is 10 to 100 msec, and the handling is very convenient.

By the way, even if the magnetostrictive stress measurement method is used, the actual measurement is performed by holding the magnetostrictive sensor by hand and applying it to the measurement points on the outer peripheral surface of the columnar material, and the measurement work is complicated when there are many measurement points. Further, since the processing of the measurement data detected by the magnetostrictive sensor is also recorded in the data recorder and processed offline, the final measurement result cannot be automatically obtained.

For this reason, there has been an increasing demand for the practical application of an apparatus that can quickly and simply perform automatic magnetostrictive stress measurement on site even if there are many measurement points on the outer peripheral surface of the columnar material.

[Problems to be Solved by the Invention] Therefore, in the present invention, when performing magnetostrictive stress measurement on a cylindrical material such as a round bar or a tube, the processes from positioning of the magnetostrictive sensor, detection of measurement data, recording to processing are collectively performed. An object of the present invention is to provide a magnetostrictive stress measuring device that can be quickly and automatically performed.

[Means for Solving the Problems] A magnetostrictive stress measuring device according to the present invention is capable of traveling on the outer peripheral surface of a cylindrical material guided by a ring gear mounted on the outer peripheral surface of the cylindrical material, and being constant from the outer peripheral surface. A traveling device having a magnetostrictive sensor held vertically to the height, a traveling device drive mechanism having a motor for driving the traveling device in the circumferential direction of the columnar material, and an encoder for detecting the amount of movement of the traveling device from the amount of rotation of the motor. And a motor drive circuit for driving and controlling the motor,
A motor drive command is issued to the motor drive circuit based on the position data of the travel device movement / stop, and when the encoder detection value reaches the drive command set value, the motor drive is stopped to control the travel device position. The measuring device control circuit, the measuring data memory for digitally converting and storing the measured data of the electric signal proportional to the magnetic anisotropy of the magnetostrictive sensor at each measuring point on the outer peripheral surface of the cylindrical material, and the measuring data memory. Data measurement processing circuit that reads out the measured data and calculates the stress distribution in the circumferential direction of the cylinder material by approximating the stress distribution in the cylindrical material with a sine curve from the measured data, and the data processed by the data calculation processing circuit. The display means for displaying is comprised.

[Operation] In the present invention, the traveling device drive mechanism for moving the traveling device having the magnetostrictive sensor on the outer peripheral surface of the columnar material has a motor, and the motor is provided with an encoder, and the measuring device control circuit is provided. The motor is driven by the motor drive circuit by issuing a drive command to move / stop the traveling device based on the position data to the motor drive circuit, and the motor is stopped when the detected value of the encoder reaches the set value of the drive command. Therefore, it is possible to automatically position the magnetostrictive sensors at a plurality of measurement points with respect to the outer peripheral surface of the cylindrical material based on the position data. In addition, the measurement data of the magnetostrictive sensor at each measurement point thus positioned is stored in the measurement data memory, and the data arithmetic processing circuit reads the measurement data stored in the measurement data memory and uses the least squares method from the measurement data. Since the stress distribution in the circumferential direction of the cylindrical material is approximated by a sine curve and calculated and the display means displays the sine curve as data, a continuous magnetostrictive stress measurement without contact with the cylindrical material is performed. About, it became possible to quickly and automatically carry out the process from detection and recording of measurement data to processing.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a longitudinal side view showing an embodiment of the present invention, FIG. 2 is a plan view of a magnetostrictive stress measuring device, and FIG. 3 is another longitudinal side view of the magnetostrictive stress measuring device.

As shown in these drawings, in this embodiment, a ring gear 100 mounted on the outer peripheral surface 11 of the columnar material 1, a traveling device 110 that is guided by the ring gear 100 on the outer peripheral surface 11 of the columnar material 1, and travels by itself. The sensor holder 130 is attached to the traveling device 110 so as to be vertically movable, and the magnetostrictive sensor 140 is vertically held on the sensor holder 130 at a constant height from the surface to be measured.

In the configuration of each part, the ring gear 100 is composed of two semi-arcuate ring gear segments 101, each ring gear segment 101 is a horizontal rail part 102 and a pair of vertical rail parts 103 erected on the horizontal rail part 102, and one And external teeth 104 attached to the vertical rail portion 103. An upper taper surface 105 and a lower taper surface 106 are provided on both sides of the horizontal rail portion 102, respectively. In addition, the pair of vertical rail portions 103 of one ring gear segment 101.
Clamp screws 107 are rotatably attached to both ends of the pair of vertical rail portions 103 of the other ring gear segment 101, and clan receiving plates 108 into which the clamp screws 107 are inserted are attached to both ends of the vertical rail portions 103, respectively. The clamp screw 107 is inserted into the clan receiving plate 108, the clamp nut 109 is fastened to the clamp screw 107, and the two ring gear segments 101 are combined to form the ring gear 100.

The traveling device 110 includes a traveling device main body 111 that moves along the ring gear 100 and a ring gear grip body 112 that grips the ring gear 100. The traveling device main body 111 includes a sensor holder mounting cylinder portion 113, a servo motor 115 to which an encoder 114 is coupled, a drive gear 116 that is connected to the servo motor 115 via a reduction gear 115a, and that meshes with the external teeth 104 of the ring gear 100. A horizontal support shaft 117 and a cam follower 118, which is a plurality of gripping parts rollingly contacting the upper and lower tapered surfaces 105 and 106 on one side of the ring gear 100, are provided. Therefore, the traveling device drive mechanism for moving the traveling device 110 is the ring gear 100.
External teeth of the vehicle, the servomotor 115 and the drive gear of the traveling device 110.
It is composed of 116 and. Further, the ring gear grip body 112 is fitted into the horizontal support shaft 117 of the traveling device main body 111 and horizontally movable for gripping, and the horizontal gripping cylinder 119 is urged in a direction away from the traveling device main body 111. Spring 1
20 and the horizontal tube 1 for gripping by being screwed onto the end of the horizontal support shaft 117.
An adjusting screw 121 for preventing the disengagement of 19 and adjusting the distance of the horizontal gripping cylinder 119 from the traveling device main body 111 according to the advance / retreat state, and a gripping arm 12 hanging from the horizontal gripping cylinder 119.
2 and a cam follower 123, which is a plurality of gripping parts attached to the gripping arm 122.

Further, the sensor holder 130 is vertically movably inserted into the sensor holder mounting cylinder portion 113 of the traveling device main body 111, and has a shaft 131 provided with a retaining portion 131a at the upper portion, and a spring 132 for urging the shaft 131 downward. A shaft attachment member 133 attached to the lower end of the shaft 131, a U-shaped connection arm 135 rotatably attached to the shaft attachment member 133 via a first horizontal shaft 134, and both ends of the connection arm 135. And a second horizontal axis 136 perpendicular to the first horizontal axis 134.
And a sensor holder body 137 that is pivotally supported via. Below the sensor holder body 137, a plurality of guide rollers 138 that are in rolling contact with the surface to be measured are provided. In addition, the sensor holder body 137 has a magnetostrictive sensor 140
The lower end surface 141 thereof is fixed by a set screw 139 so as to maintain a constant minute height h above the surface to be measured.

Next, the assembling of the magnetostrictive stress measuring device to the columnar material 1 will be described. First, for example, the outer peripheral surface 11 of the cylindrical material 1 of the tube
The two ring gear segments 101 are connected to the moving position in (1) and the ring gear 100 is set on the columnar material 1.

Next, the drive gear 116 of the traveling device main body 111 is set to the ring gear 100.
The traveling device 110 is installed on the ring gear 100 by meshing with the external teeth 104 attached to one of the vertical rail portions 103. At this time, the traveling gear body 111 is moved by the ring gear gripper 112.
By holding the ring gear 100 with and, the traveling device 1
Ring gear 1 without 10 falling out of ring gear 100
It is set to run at 10.

On the other hand, the magnetostrictive sensor 140 is vertically held on the sensor holder body 137 of the sensor holder 130, and is set so as to be maintained at a constant height from the surface to be measured.

Therefore, when the servomotor 115 is driven, its rotational force is transmitted to the drive gear 116 via the reduction gear 115a, and when the drive gear 116 rotates, the ring gear 100 meshing with this is transmitted.
The rotational force of the drive gear 116 is converted into a linear motion by the external teeth 104 of the driving gear 110, and the traveling device 110 is guided by the ring gear 100 and travels around the outer peripheral surface 11 of the columnar material 1. At this time, the magnetostrictive sensor 140 also moves together with the traveling device 110.

The mechanical configuration of this embodiment is as described above, and the electrical configuration of this embodiment will be described next.

FIG. 4 is a block diagram showing the control system of the embodiment of the present invention.

200 is a magnetostrictive amplifier that amplifies the electric signal of the magnetostrictive sensor 140,
201 is an A / D converter that converts the electric signal amplified by the magnetostrictive amplifier 200 from analog to digital, and 202 stores the measurement data of the electric signal that is digitally converted by the A / D converter 201 in the measurement data memory 203,
A data arithmetic processing circuit for reading this and arithmetically processing so as to obtain the stress distribution in the circumferential direction of the cylindrical material 1, 204 is a CR
T, 205 is a printer, 206 is a keyboard, 207 is a position data memory for storing the position data of a preset measurement location on the outer peripheral surface 11 of the cylindrical material 1, and 208 is the servomotor 1
A motor drive circuit for controlling the drive of 15; 209 reads the position data from the position data memory 207 to output the motor drive circuit 2;
A measuring device control circuit for giving a rotation / stop command to the servomotor 115 to 08, and 210 is a stress data memory for storing the stress distribution data obtained by arithmetic processing by the data arithmetic processing circuit 202.

5 (a) and 5 (b) are explanatory diagrams when a bending stress is applied to the columnar material and a stress distribution diagram at that time, and FIG. 6 is an explanatory diagram showing a running state of the magnetostrictive sensor.

Before explaining the operation of this embodiment, the principle of the magnetostrictive stress measuring method will be described with reference to FIGS. 5 (a) and 5 (b).

In general, the stress distribution when a bending load is applied to a cylindrical material as shown in Fig. 5 (a) is
As in (b), it becomes a sine curve. When an axial load is applied in addition to the bending load, the neutral position of this sine curve moves upward or downward depending on whether the axial load is tensile or compressive. In the case of FIG. 5 (b), a tensile load is applied.

A similar sine curve can be obtained by running the magnetostrictive sensor 2 over the entire circumference of such a cylindrical material 1 and measuring the magnetic anisotropy, that is, the magnetostriction over the entire circumference as shown in FIG.

If this is expressed by an equation, it can be expressed as follows.

V = Asin (θ + ω) + B (1) However, V: Output voltage of magnetostrictive sensor A: Amplitude B: Offset amount θ: Circumferential angle of cylindrical material ω: Phase shift Amplitude A in this equation is a large bending stress The offset amount B is a stress that is irrelevant to the circumferential angle θ,
That is, it is considered to be a value that changes depending on the axial stress.
The phase shift ω indicates the relative positional relationship between the measurement start point and the material mechanical neutral axis.

Since the diagram of the output voltage of the magnetostrictive sensor thus obtained usually contains a ripple due to the nonuniformity of the material to be measured, the ripple component is smoothed by the statistical processing of the measured data, that is, the least square method. It is approximated to equation (1).

Next, the operation of this embodiment will be described.

First, the running operation of the magnetostrictive stress measuring device for a cylindrical material will be described based on the flowchart of FIG.

First, the traveling device 110 is set and set in advance at the measurement origin of the outer peripheral surface 11 of the columnar material 1. Next, the keyboard 206 is operated to cause the position data memory 207 to store the position data of a plurality of measurement points set at a constant pitch interval with respect to the outer peripheral surface 11 of the cylindrical material 1, and the position data is input (step S).
1). The measuring device control circuit 209 reads the position data memory 207 and drives the servomotor 115 to move the traveling device 110 in the circumferential direction based on the position data (step S).
2). The encoder 114 detects the amount of movement of the traveling device 110 in the circumferential direction from the amount of rotation of the servo motor 115 (step S
3). Then, the measuring device control circuit 209 determines whether or not the detected value of the encoder 114 matches the position data (step S4).

If the detected values match, the measuring device control circuit 20
9 issues a drive stop command for the servo motor 115 to the motor drive circuit 208 to stop the movement of the traveling device 110 (step S5). In this way the traveling device
When the 110 is positioned, the magnetostrictive sensor 140 provided in the traveling device 110 is also positioned.

When the positioning of the magnetostrictive sensor 140 with respect to the measurement point is completed in this way, the magnetostrictive sensor 140 then detects an electric signal proportional to the magnetic anisotropy from the measurement point (step S6). The detected value of the electric signal of the magnetostrictive sensor 140 is the measurement data memory 203.
(Step S7). Then, whether or not there is position data at the next measurement point is read out (step S8), and if there is no position data at the next measurement point, the process ends, and if there is next position data, the address of the position data becomes +1. (Step S9). If the next position data is the second measurement point, the traveling device 110 is moved from the first measurement point to the second measurement point, and the next measurement point is measured in steps S1 to S7 described above.

In this way, the measurement is automatically performed sequentially at each measurement point. In this embodiment, the measuring pitch between the measuring points is, for example, a pitch of 5 ° for the cylindrical material 1 of the steel pipe having a diameter of 300 mm, and is set appropriately according to the diameter of the cylindrical material 1.

Next, the processing of the measurement data detected by the magnetostrictive sensor will be described based on the flowchart of FIG.

When the magnetostrictive sensor 140 is positioned at the measuring point of the columnar material 1, the magnetostrictive sensor 140 detects an electric signal proportional to the magnetic anisotropy (step S20). Next, since the electric signal detected by the magnetostrictive sensor 140 is analog, A /
The data is converted to digital by the D converter 201 and stored in the measurement data memory 203 by the data arithmetic processing circuit 202 (step S21). When the magnetostrictive sensor 140 is positioned at the next measuring point, the electric signal is detected by the magnetostrictive sensor 140 as in step S20, the electric signal is converted into digital data and stored in the measurement data memory 207 (steps S22, S2).
3). Then, in the data arithmetic processing circuit 202, the measurement data is stored in the measurement data memory at all preset measurement points.
It is determined whether or not it is stored in 203 (step S24).
When the measurement data for all the measurement points is stored, the data arithmetic processing circuit 202 reads the data for all the measurement points from the measurement data memory 203, and the statistical processing method is used from the measurement data for each measurement point. The stress distribution in the circumferential direction of the cylindrical material 1 is approximated by a sine curve by the least squares method. The circumferential angle of the cylindrical material 1 can be determined from the phase of the sine curve, and the magnitude of bending stress can be determined from the amplitude of the sine curve (step S25).

The phase and amplitude, which are the stress data of this sine curve, are stored in the stress data memory 210 (step S2
6), the data processing circuit 202 receives the stress data from the CRT.
By displaying the graph as shown in FIG. 9 in 204, the magnetostrictive stress distribution of the columnar material 1 can be known (step S27). The stress data can be printed on the sheet S and displayed by the printer 205 as shown in FIG.

[Advantages of the Invention] As described above, according to the present invention, the traveling device drive mechanism for moving the traveling device having the magnetostrictive sensor on the outer circumferential circle of the columnar material has a motor, and the encoder is attached to the motor. The measurement device control circuit issues a drive command to the motor drive circuit to move / stop the traveling device based on the position data, and the motor is driven by the motor drive circuit. Since it is performed when the set value is reached, there is an effect that the positioning of the magnetostrictive sensors at a plurality of measurement points with respect to the outer peripheral surface of the cylindrical material can be automatically performed based on the position data.

Furthermore, the measurement data of the magnetostrictive sensor at each positioned measurement point is stored in the measurement data memory, the data calculation processing circuit reads the stored measurement data in the measurement data memory, and the calculation processing is performed from the measurement data by the least square method. By calculating the stress distribution approximate to the sine curve of the cylindrical material in the circumferential direction and displaying the data of the stress distribution on the display means, the process from detection / recording to processing of the measured data for the cylindrical material can be performed at once. It has the effect that it can be quickly and automatically performed, the magnetostrictive stress can be measured in a short time, and the stress state actually working can be measured with high reliability and high accuracy.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention, FIG. 2 is a plan view of a magnetostrictive stress measuring device, FIG. 3 is another vertical side view of the magnetostrictive stress measuring device, and FIG. 4 is an embodiment of the present invention. A block diagram showing an example control system, FIGS. 5 (a) and 5 (b) are explanatory diagrams when a bending stress is applied to a cylindrical material and a stress distribution diagram at that time, and FIG. 6 shows a running state of the magnetostrictive sensor. FIG. 7 is a flow chart showing the running operation of the magnetostrictive stress measuring device, FIG. 8 is a flow chart showing the processing of the measurement data of the magnetostrictive stress measuring device, and FIG. 9 is a sine curve of the measured stress data. FIG. 10 is a plan view showing the sheet on which the measured stress data is printed. 1 …… Cylinder material, 11 …… Outer peripheral surface, 100 …… Ring gear, 1
04 …… External teeth (travel device drive mechanism), 110 …… Travel device, 1
15: Servo motor, 116: Drive gear (travel device drive mechanism), 140: Magnetostrictive sensor.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Sadaaki Sakai 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. (56) Reference JP-A-1-308933 (JP, A) 1-135339 (JP, U)

Claims (1)

[Scope of utility model registration request] 1. A traveling device having a magnetostrictive sensor, which is guided by a ring gear mounted on the outer peripheral surface of a columnar material and can travel freely on the outer peripheral surface of the columnar material, and which is vertically held at a constant height from the outer peripheral surface. A traveling device drive mechanism having a motor that drives the traveling device in the circumferential direction of the columnar material; an encoder that detects the amount of movement of the traveling device from the amount of rotation of the motor; a motor drive circuit that drives and controls the motor; Measures to issue a motor drive command to the motor drive circuit based on the movement / stop position data, and stop the motor drive when the encoder detection value reaches the drive command set value. A device control circuit, a measurement data memory for digitally converting and storing the measurement data of an electric signal proportional to the magnetic anisotropy of the magnetostrictive sensor at each measurement point on the outer peripheral surface of the cylindrical material, and a measurement data memory. A data operation processing circuit that reads out the measurement data stored in the data memory, performs an operation process from the measurement data by the least squares method, and obtains a stress distribution in the circumferential direction of the cylindrical material by approximating with a sine curve, and a data operation processing circuit And a display unit for displaying the data processed by the above.