JPH0569662U - Bending test device for sensor cable - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a bending test apparatus for a sensor cable, which can accurately and easily measure a zero point variation when the sensor cable is bent. [Structure] A table 22, and a cable 19 attached to one side of the table 22 and connected to a measuring device 60,
A first fixing tool 23 for fixing the output end side of 20 and a rotation axis A perpendicular to the other on the table 22 are rotatably and horizontally movably mounted, and are fixed around the rotation axis A. 24 having a curved surface 37 of the mandrel, a second fixture 25 for fixing the curved end 37 of the mandrel 24 along the input end side of the cables 19 and 20, and the mandrel 24.
A bending test apparatus for a sensor cable, which is detachably provided on the above, and includes a sensor main body 50 connected to the input ends of the cables 19 and 20.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a bending test apparatus for a sensor cable used in a torque sensor or the like that utilizes magnetostrictive characteristics.

[0002]

[Prior Art]

 First, as a typical example in which a sensor cable tested by a bending tester is used, a torque sensor using magnetostrictive characteristics will be described with reference to FIG. The sensor main body 50 has grooved portions 52 and 53 formed on the sensor shaft 51 in a direction of 45 ° with respect to the lengthwise direction of the shaft. The grooved portions 52 and 53 have excitation coils 54a and 54b and detection coils 55 and 5, respectively. 6 are opposed to each other. When torque is applied to the sensor shaft 51, tensile stress is applied to the grooved portion 52 in the groove direction and compressive stress is generated in the grooved portion 53 in the groove direction. The direction of change is the opposite. If the changes in the magnetic permeability are detected by the coils 55 and 56, and the difference in the voltage generated between the coils is taken out by the detection unit 57, the change in the magnetic permeability due to factors other than the torque is canceled out, and the torque is canceled. Only the change in magnetic permeability due to can be taken out.

In order to guide the voltage extracted from the detection coils 55 and 56 of the sensor body to the detection unit 57, and to pass the exciting current from the exciting power source 581 of the exciting unit 58 to the exciting coil 54, the conductor 1, A sensor cable in which a core 6 having 2 and 3 and a core 7 having conductors 4 and 5 are put together is used. The standard cable 19 of FIG. 4 was used as the sensor cable. Each of the conductors 1, 2 and 3 covered with an insulator 11 is twisted together, and a shield layer 16 composed of a press winding tape 16a, a braided shield 16b, and a press winding tape 16c is provided thereon to form a core 6. Then, the conductors 4, 5 covered with the insulator 11 are twisted together, and a shield layer 16 composed of a press winding tape 16a, a braided shield 16b, and a press winding tape 16c is provided thereon to form the core 7. These cores 6 and 7 are used as a sensor cable 19 via an inclusion 12, a pressing tape 13 and an outer sheath 14. The detection unit 57 includes rectifier circuits 571 and 572 and a differential amplifier 573, and the conductors 4 and 5 are connected to the output terminals 4b and 5b of the excitation power source 581 of the excitation unit 58.

By the way, when torque is not applied to the sensor shaft 51 in FIG. 3, the output voltage of the detection unit 57 should be zero, and thus zero adjustment is performed. It was found that the zero point fluctuates when the cable 19 is bent when the sensor cable 19 described in FIG. 4 is used. As a result of diligent examination of the cause of the change, when the cable 19 is bent, the distance between the conductors changes, and the zero point may change due to the change in the capacitance per unit length of the conductor. found . For example, in the state where the cable is straightened, even if the output voltage between the terminals 1a-3a of the detection coils 55 and 56 and 2a-3a in FIG. 3 is equal, when the cable is bent, the conductor 1 and the conductor 3 of FIG. When the space between them becomes closer and the capacitance increases, the voltage between the input terminals 1b-3b of the detection unit 57 becomes larger than the voltage between 2b-3b, and the output balance of the rectifying circuits 571 and 572 is lost, The output of the differential amplifier 573 is generated, and the zero point fluctuates.

Therefore, it has been proposed to use the coaxial cable structure shown in FIG. 5 as a structure in which the capacitance between conductors is unlikely to change (not yet published). In Fig. 5, two inner conductors 1 and 2 each having an insulator 11, an outer conductor 3 ', and an inner sheath 17 arranged in order are arranged to form a coaxial core 8 covered with a braided shield 18. The conductors 4 and 5 coated with an insulator 11 are twisted together to form a twisted core 9, and the cores 8 and 9 are used for a sensor via an inclusion 12, a pressing tape 13 and an outer sheath 14. The cable 20 is used. In addition, since the insulator 11 needs heat resistance, a fluorine resin is used. By using this coaxial cable 20 as a sensor cable, the change in the electrostatic capacitance between the inner conductor 1 and the outer conductor 3'when the cable 20 is bent is reduced, and a considerable improvement can be made against the above-mentioned zero point fluctuation. We were able to achieve it, but we did not reach the rate of change to zero. Therefore, we made the improvements shown in "Method for manufacturing sensor cable" (Japanese Patent Application No. 3-246610), and were able to realize the sensor cable 20 with less zero fluctuation.

[0006]

[Problems to be solved by the device]

 Therefore, when manufacturing a cable by the "sensor cable manufacturing method", various inspection methods were also examined as a result of confirming that the capacitance between conductors is sufficiently stable as the quality of the cable itself. A simple method is to connect the test cable 20 between the sensor body 50 and the measuring instrument 60, and evaluate the cable performance by directly determining the change in the capacitance between the conductors of the cable 20 as the magnitude of the zero point fluctuation of the sensor. And since it is excellent, I decided to use it. Conventionally, in order to perform this test, as shown in FIG. 6, a test cable 19, 20 of about 2 m is attached between the sensor main body 50 and the measuring device 60 and placed on the table 22. Measure the zero point in a straightened state, then hold the sensor body 50 in your hand and wind the cables 19 and 20 around a predetermined jig 24 (mandrel with a diameter of 200φ), and finish the winding with the zero point in the process. The zero point is recorded. Next, the method of extending the cables 19 and 20 again and recording the zero point was performed. This manual bending of the cable is troublesome, and the winding method of the cable around the mandrel varies, and the test is inaccurate.

The present invention has been made in view of the above problems of the conventional technique, and an object of the present invention is to accurately and easily measure a zero point variation when a sensor cable is bent. It is intended to provide a bending test device for a sensor cable.

[0008]

[Means for Solving the Problems]

 The bending test apparatus for a sensor cable according to the present invention includes a table 22 and a first fixture 23 that is attached to one of the tables 22 and that fixes the output ends of the cables 19 and 20 connected to the measuring device 60. A mandrel 24 having a rotation axis A perpendicular to the other on the table 22 and rotatably and horizontally movable, and having a predetermined curved surface 37 around the rotation axis A, and the mandrel 24. A second fixing tool 25 for fixing the input ends of the cables 19 and 20 along the curved surface 37 of the and the mandrel 24 is detachably provided and connected to the input ends of the cables 19 and 20. It consists of a sensor body 50.

[0009]

[Action]

 By simply moving the mandrel 24 horizontally while rotating it, the cables 19 and 20 are bent along a predetermined bending surface 37 of the mandrel 24, and the bent portion of the cable is fixed to the first fixing tool 23 and the second fixing tool. It is separated from the sensor main body 50 and the like by the tool 25, and other portions do not bend during measurement, and only the zero point fluctuation due to a predetermined bend is measured.

[0010]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings. 1 is a top view of the bending test apparatus of the present invention, and FIG. 2 is a side view of the bending test apparatus of the present invention.

In FIG. 1 and FIG. 2, the bending test apparatus 21 includes a table 22, a first fixing tool 23, a mandrel 24, a second fixing tool 25, and a sensor main body 50 as main parts. Is.

The table 22 has a rectangular horizontal surface 31, and the first fixture 23 is attached to one of the horizontal surfaces 31. The first fixture 23 has a split structure and fixes the output ends of the cables 19 and 20 with bolts or the like via a cushioning material such as felt. The mandrel 24 is placed on the other side of the horizontal surface 31. Also, 32 is a removable block base that supports the cables 19 and 20 substantially horizontally, and 33 is a connector that connects the cables 19 and 20 to a measuring device 60 including a detection unit 57, an excitation unit 58, and a pen recorder 59. It is for connecting.

The mandrel 24 includes a body portion 37 that forms a curved surface between a lower surface flange 35 and an upper surface flange 36. At least three casters are attached to the lower surface of the lower surface flange 35, and the mandrel 24 is rotatably and horizontally movable while being placed on the horizontal surface 31 of the table 22. The rotation axis A of the body portion 37 is perpendicular to the table 22 and its radius R is set so as to form a desired curved surface, and the second fixed portion is provided on the side surface of the body portion 37 or the lower surface of the upper flange 36. The fittings are attached. The curved surface of the body portion 37 may be elliptical or the like. The second fixture 25 has a split structure, and fixes the input ends of the cables 19 and 20 with bolts (via a cushioning material such as felt). A sensor body 50 is detachably provided on the upper surface flange 36 with a bolt or the like, and the sensor body 50 and the cables 19 and 20 are connected via a connector 39. It should be noted that the present invention also includes the mandrel 24 in which the upper flange 36 is omitted and the mandrel 24 has a structure in which the flange and the body can be easily replaced with any desired one.

Next, the operation of the zero-point fluctuation measuring device 21 described above will be described with reference to FIG. At the time of measurement, as shown in the figure, the output ends of the cables 19 and 20 are fixed by the first fixture 23, and the input ends thereof are fixed by the second fixture 25 of the mandrel 24. Then, the output ends of the cables 19 and 20 are connected to the measuring unit 60 such as the detecting unit 57 and the exciting unit 58 via the connector 33, and the input ends thereof are connected to the sensor main body 50 via the connector 39. Then, in block 32, the cables 19 and 20 are maintained substantially horizontal. Next, the lower flange 35 of the mandrel 24 is manually rotated in the direction while being careful not to apply an excessive force to the cables 19 and 20, and simultaneously moved in the direction. The cables 19 and 20 are wound around the body portion 37 around the vertical rotation axis A of the mandrel 24, so that a predetermined bend with a radius R is imparted. Then, the zero-point fluctuation associated with the bending is recorded in the pen recorder 58 connected to the detection unit 57 together with the passage of time. The measurer can impart a predetermined bend to the cables 19 and 20 by a simple operation of rotating and moving the mandrel 24 with casters, and there is no individual difference. Further, since the sensor main body 50 is attached to the mandrel 24, even if the mandrel 24 is moved, the cables 19 and 20 from the second fixing tool 25 to the sensor main body 50 do not move and no error occurs.

The mandrel 24 of the bending test apparatus 21 described above is rotatably and horizontally movable by casters. However, instead of the casters, a slide that horizontally slides on the table is provided and the mandrel 24 stands on this slide. It is also possible to adopt a structure in which the mandrel 24 is rotatably supported on an installed shaft.

[0016]

[Effect of the device]

 The bending test apparatus for a sensor cable according to the present invention bends the cable along a desired bending surface only by the operator moving the mandrel horizontally while rotating the mandrel, and the bending portion of the cable has the first fixing tool and the second fixing tool. Since it is isolated by the fixture and does not affect other parts, it is possible to measure the zero-point fluctuation accurately without variation by the operator. In addition, it becomes possible to measure the change in zero point over time during bending under the same conditions.

[Brief description of drawings]

FIG. 1 is a top view of a bending test apparatus of the present invention.

FIG. 2 is a side view of the bending test apparatus of the present invention.

FIG. 3 is a device layout diagram of a torque sensor.

FIG. 4 is a structural diagram of a sensor cable.

FIG. 5 is a structural diagram of a sensor cable.

FIG. 6 is a side view showing a conventional bending test.

[Explanation of symbols]

 19, 20 Cable 22 Table 23 First Fixing Tool 24 Mandrel 25 Second Fixing Tool 37 Body (Bending Surface) 50 Sensor Main Body 60 Measuring Instrument A Rotating Shaft

Continuation of the front page (72) Creator Yuuji Fujikawa 2-3-1 Iwata-cho, Higashi-Osaka City, Osaka Prefecture Tatsuta Electric Cable Co., Ltd.

Claims (1)

[Scope of utility model registration request] 1. A table, a first fixture attached to one side of the table for fixing an output end side of a cable connected to a measuring instrument, and a rotary shaft perpendicular to the other side of the table. And a mandrel having a predetermined bending surface around the rotation axis, which is rotatably and horizontally movable.
A sensor cable comprising a second fixture for fixing the input end side of the cable along the curved surface of the mandrel and a sensor body detachably provided on the mandrel and connected to the input end of the cable. Bending test equipment.