JP3237970B2 - High frequency heating equipment for material testing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a high frequency heating apparatus for a material testing machine which is attached to a material testing machine for applying an external force while heating the test piece, and heats and air cools the test piece.

[0002]

2. Description of the Related Art Many diesel engines, the above-mentioned turbines, gas turbines, jet engines, high-temperature pressure vessels, and chemical reactors receive repeated thermal stresses due to temperature changes due to repeated start and stop of operation. Thermal fatigue is one of the most important strength phenomena that affect the performance, stability, life, etc. of high temperature equipment or structures.

[0003] Among the thermal fatigue tests, a superposition type test in which mechanical strain is applied is designed to give an arbitrary magnitude of strain amplitude under a constant temperature amplitude. This thermal fatigue subjected to repetition of a temperature cycle and an external force is referred to as thermal fatigue or thermomechanical fatigue in which mechanical stress is superimposed.

Conventional testing machines for performing this type of testing include the techniques described in Japanese Patent Application Laid-Open Nos. 62-12834 and 62-206429. As shown in an explanatory diagram of FIG. 6, a material testing machine described in this publication includes a hydraulic cylinder 1 provided on a base of the testing machine, a servo valve 2 for supplying oil pressure to the hydraulic cylinder 1, and a testing machine. A chuck 5 for holding both ends of a test piece 4 at a lower portion of a load cell 3 provided at an upper portion of the
Is provided.

[0005] A displacement detector 6 for detecting the displacement of the piston rod 1a is attached to the material tester.
A distortion detector 7 for detecting distortion of the test piece 4 is provided.
A plurality of heating rings are formed around the test piece 4 and wound up and down in a coil shape. The heating ring has a heating coil connected to a high frequency generator. The heating means heats the test piece 4 by high frequency. A cooling means having an air ejection hole that is connected to an air pressure source through an opening adjustment valve (not shown) and that is open on the inner surface of the air pipe. A high-frequency heating device 8 is provided, and a temperature detector 9 is fixed to the test piece 4.

Then, data set to give a predetermined temperature cycle is input to the control unit 10 in advance,
The data is read out during the material test to control the energization of the high-frequency heating coil, and is cooled by the amount of air swelling from the air ejection holes of the heating coil, so that the temperature of the test piece 4 is controlled to move up and down with time. I have.

[0007]

In order to accurately control the temperature of the test piece 4 so that the temperature does not become uneven, (1) To prevent deformation of the heating coil. (2) The shape of the heating coil can be finely adjusted while the test piece 4 is being heated. is necessary. An object of the present invention is to solve such a problem, and based on a signal from a temperature detector fixed to a test piece, high-frequency heating that can fine-tune the interval between a plurality of heating rings constituting a heating coil. An apparatus is provided.

[0008]

In order to achieve the above-mentioned object, a high-frequency heating apparatus for a material testing machine according to the present invention comprises a tubular conductor having a cooling water passage formed therein, which is wound in a coil shape to form a coil. Constituting a heating coil having a plurality of heating rings connected to the air ring provided inside each heating ring,
A cooling means having an air ejection hole opened on the inner side surface of the air pipe, a connection pipe connected to the air pipe connected to an air pressure source via an opening adjustment valve, and a high-frequency heating coil. In the high frequency heating apparatus for a material testing machine, comprising a heating means connected to the generator and heating the test piece attached to the material testing machine at high frequency, and temperature detectors attached to a plurality of locations on the test piece. On one side, nuts made of an insulating material having different helical angles are provided, and a driven portion is provided at an end of a threaded rod having a helical angle to be screwed to each of the nuts. A control unit for controlling the opening degree adjustment valve and the high frequency generator is provided.

[0009]

The high-frequency heating apparatus for a material testing machine constructed as described above drives the driven part to remove the screw rod when the temperature of the test piece becomes uneven in the vertical direction due to the signals of the plurality of temperature detectors. Rotate. Since the threaded rods are screwed into nuts with different helical angles, if it is necessary to raise the temperature of the upper and lower ends of the test piece, rotate the threaded rod in one direction to increase the distance between the heating rings. If it expands, and conversely, it rotates in the other direction to reduce the interval between the heating rings. Thus, the unevenness of the temperature in the vertical direction of the test piece is finely adjusted.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a plan view of a high-frequency heating apparatus 11 for a material testing machine, FIG. 2 is a side view of FIG. FIG. 4
3 is a sectional view taken along line XX of FIG. 3, and FIG. The heating coil 12 of the high-frequency heating device 11 is formed from a cylindrical copper material having a cooling water passage 13 therein (see FIG. 3), and is wound in a substantially coil shape at a central portion and formed in a ring shape with a part cut away. Three heating rings 14a, 14b, 14c arranged vertically
And an internal connecting pipe 15 for connecting the heating rings 14a and 14b and the heating rings 14b and 14c respectively (see FIGS. 2, 3 and 5). A recess 21 for accommodating the electric wire is formed (see FIG. 1).

Both ends of the heating coil 12 become an external connecting pipe 16 extending outward from the upper heating ring 15a and the lower heating ring 15c. A cooling water pipe is provided at a flange 20 provided at an end of the external connecting pipe 16. A path (not shown) is connected (see FIG. 1) to prevent the heating coil 12 from overheating. Each of the heating rings 14a, 14b, 14c is connected to a high-frequency generator (not shown), and constitutes heating means for high-frequency heating the test piece 4 inside the heating coil 12 (see FIG. 1).

An air line 17 is provided inside each of the heating rings 15a, 15b, 15c, and a plurality of air ejection holes 18 are formed in the inner surface of each air line. The connection pipes 19 are connected (see FIGS. 1 and 3). The connection pipe 19 is connected to a pneumatic source (not shown) via an opening adjustment valve (not shown), and constitutes cooling means for cooling the test piece 4 by air ejected from the air ejection holes 18.

Each heating ring 14a, 14b, 14c is provided with a nut 22 made of an insulating material on the opposite side of the notch. The helical angle of the nut 22 differs for each heating ring 14a, 14b, 14c.
The center heating ring 14b has a spiral angle of zero, and one of the upper and lower heating rings 14a and 14c has a right-hand thread and the other has a left-hand thread. A threaded rod 23 having the same helical angle as each of the nuts 22 is screwed into the three nuts 22.

The driven part 2 provided at the end of the screw rod 23
Reference numeral 4 denotes a knob for manual operation, but it is also possible to perform automatic control by connecting to a small motor that is driven to rotate by a command from the control unit. Next, the operation of the high-frequency heating apparatus for a material testing machine configured as described above will be described.

As in the conventional example, the test piece 4 inserted into the high-frequency heating device 8 is attached to the chucks 5 and 5 of the material testing machine, and the temperature detector 9 is attached to the test piece 4. At this time, since the electric wire of the temperature detector 9 can be accommodated in the concave portion 21, there is an advantage that the test piece 4 to which the electric wire is heated is not affected by heat. An operation of supplying a high-frequency current to the heating rings 14a, 14b, and 14c to heat the test piece 4 based on a predetermined program stored in the control unit 10 and cooling the test piece 4 by blowing air from the air ejection holes 18 onto the test piece 4. And strain is measured by applying a load to the test piece 4 by a material testing machine.

The test piece 4 is operated by signals from a plurality of temperature detectors 9.
If the temperature unevenness occurs in the vertical direction of the
To rotate the screw rod 23. Since the screw rods 23 are screwed to the nuts 22 having different helical angles, when it is necessary to increase the temperature of the upper and lower ends of the test piece 4, the screw rods 23 are rotated in one direction to heat. Ring 14a,
The distance between the heating rings 14a, 14b, 14c is reduced by expanding the distance between the heating rings 14b, 14c, and conversely, rotating in the other direction. Thus, the unevenness of the temperature in the vertical direction of the test piece is finely adjusted.

[0017]

Since the present invention is configured as described above, it has the following effects. (1) Since the nut of each heating ring is screwed into the threaded rod, displacement of each heating ring is prevented, and deformation of the entire heating coil is prevented. (2) When temperature unevenness occurs in the axial direction of the test piece 4, the control unit drives the screw rod to rotate based on the signal of the temperature detector, so that the interval between the heating rings can be finely adjusted.

[Brief description of the drawings]

FIG. 1 is a plan view of a high-frequency heating device for a material testing machine.

FIG. 2 is a side view of FIG.

FIG. 3 is a longitudinal sectional view of FIG.

FIG. 4 is a sectional view taken along line XX of FIG. 3;

FIG. 5 is an explanatory diagram of a shape of a high-frequency heating device for a material testing machine.

FIG. 6 is an explanatory diagram of a structure of a material testing machine.

[Explanation of symbols]

 Reference Signs List 4 Test piece 8, 11 High-frequency heating device 9 Temperature detector 10 Control unit 12 Heating coil 13 Cooling water passage 14a, 14b Heating ring 14c Heating ring 17 Air passage 18 Air ejection hole 19 Connection pipe 21 Depression 22 Nut 23 Screw rod 24 Cover Drive part

────────────────────────────────────────────────── ─── Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01N 3/00-3/62 JICST file (JOIS)

Claims (1)

(57) [Claims] 1. A heating coil having a plurality of heating rings connected to each other by winding a cylindrical conductor in which a cooling water passage is formed into a coil shape, and air inside each of the heating rings. Cooling means for providing a pipe, providing an air ejection hole opened on the inner surface of the air pipe, and connecting a connection pipe connected to the air pipe to an air pressure source via an opening degree adjustment valve; The heating coil is connected to a high-frequency generator, a heating means for high-frequency heating a test piece attached to the material testing machine, and a high-frequency heating device for a material testing machine comprising temperature detectors attached to a plurality of portions of the test piece. A nut of an insulating material having a different helical angle is provided on one side of each of the heating rings, and a driven portion is provided at an end of a threaded rod having a helical angle to be screwed with each of the nuts. Open the above signal Material testing machine for high frequency heating apparatus characterized in that a control unit for controlling the control valve arrangement the high frequency generator.