JP2007127429A - Hose bending rigidity measuring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hose bending rigidity measuring device capable of measuring the bending rigidity of a flexible hose objectively and accurately. <P>SOLUTION: When a rope body 4 is pulled by a tension roller 13C by lifting of a crosshead, a pair of rotary disks 2, 2 are rotated mutually reversely, and a bending load is applied to a test hose H whose both ends are fixed to the rotary disks 2, 2 through a pair of hose fixing tools 3. In this case, a bending moment applied to the test hose H is measured by a traction load measured by a load cell 5 and each effective radius of the rotary disks 2, 2 on which the rope body 4 is wound, and a curvature of the test hose H is measured by each rotation angle of the rotary disks 2, 2 measured by an image processing device. Then, the bending rigidity of the test hose H is measured objectively and accurately by the measured bending moment and curvature. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a hose bending stiffness measuring device, and more particularly to a device for measuring the bending stiffness of a test hose such as a flexible rubber hose or resin hose.

  Rubber hoses and resin hoses that are flexible and easy to handle are generally used as transport hoses for delivering various liquids and gases, or pressure supply hoses for supplying a predetermined pressure. ing.

  This type of hose is easy to handle, but if a bending load is applied, it may be crushed due to kink or buckling, and a predetermined flow rate may not be secured. Therefore, for this type of hose, it is necessary to measure in advance how much bending load it can withstand. Conventionally, it is common to use a manual bending test or a three-point bending tester using a universal tension / compression tester. A test was being conducted.

As a device capable of measuring the bending load of this type of hose, a “structural member provided with a pair of chucks capable of gripping both ends of the hose and a weight suspended between the pair of chucks at an intermediate portion of the hose. Is generally disclosed (see, for example, Patent Document 1).
Japanese Patent No. 3336387

  By the way, in the above-described manual bending test, the measurement results are different depending on the examiner, so that objective measurement is difficult. On the other hand, in a three-point bending test using a universal tensile / compression tester, the compression jig contacts the hose surface, so the moment and curvature when the hose kinks due to irregularities on the hose surface are accurately measured. In particular, the bending stiffness of the hose in a region with a large curvature cannot be measured accurately. The “mechanical behavior observing apparatus for structural members” described in Patent Document 1 is similar in principle to the three-point bending test, and therefore has the same problem.

  That is, in the conventional example, the moment and curvature of the flexible hose cannot be measured accurately, and in particular, the bending rigidity of the hose in a region with a large curvature can be measured objectively and accurately. Can not.

  By the way, if a hose is modeled as a beam in consideration of geometric nonlinearity in a computer simulation for performing stress analysis of this type of hose, mesh creation becomes simple and calculation time can be shortened. Although rigidity is used as the constitutive law of the beam, the rigidity as the constitutive law of the beam can be calculated not only as a linear relationship but also as a relationship between nonlinear bending moment and curvature.

  Therefore, an object of the present invention is to provide a hose bending stiffness measuring device that can objectively and accurately measure the bending stiffness of a flexible hose.

  The hose bending stiffness measuring device according to the present invention is a device for measuring the bending stiffness of a flexible test hose, and can be connected to and separated from each other in the inter-axis direction from a state where the inter-axis distance is separated. A pair of supported rotary disks, a pair of hose fixtures for fixing both end portions of the test hose at left and right symmetrical positions on the side surface of each rotary disk on a center line passing through the axis of each rotary disk, and the pair And a tow that can be pulled to rotate the pair of rotary disks in opposite directions. Means, a traction load measuring means for measuring the traction load of the rope body, and a rotation angle measuring means for measuring the rotation angle of the pair of rotary disks.

  In the hose bending stiffness measuring device according to the present invention, when the pulling means pulls the cable body, the pair of rotary disks rotate in opposite directions to each other, and both end portions are connected to the pair of rotary disks via the pair of hose fixtures. A bending load is applied to the test hose to which is fixed. At that time, the bending moment acting on the test hose was measured by the traction load measured by the traction load measuring means and the effective radius of the rotary disk around which the rope was wound, and measured by the rotation angle measuring means. The curvature of the test hose is measured by the rotation angle of the rotary disk. Then, the bending rigidity of the flexible test hose is objectively and accurately measured by the measured bending moment and curvature of the test hose.

  Here, the cable body means a thread, a wire, a cord, a cable, a rope, or the like made of a single wire or a stranded wire. As materials for these cords, natural fibers, synthetic fibers, steel wires, high-strength fibers, and the like can be used.

  In the hose bending stiffness measuring device according to the present invention, the pulling means can be constituted by a cross head of a universal tensile testing machine. Further, the pulling means can be constituted by a weight whose weight is known.

  Further, the traction load measuring means may be constituted by a load cell, and a crosshead or a weight may be configured to pull the cord body via the load cell.

  Furthermore, an angle scale or an encoder as the rotation angle measuring means can be attached to the pair of rotary disks. A pair of rotary disks can be provided with a torque gauge instead of the traction load measuring means.

  According to the hose bending rigidity measuring apparatus according to the present invention, when the cord body is pulled by the pulling means and the pair of rotary disks are rotated in opposite directions, a bending load acts on the test hose. At that time, the bending moment acting on the test hose was measured by the traction load measured by the traction load measuring means and the effective radius of the rotary disk around which the rope was wound, and measured by the rotation angle measuring means. The curvature of the test hose is measured by the rotation angle of the rotary disk. Therefore, the bending rigidity of the flexible test hose can be objectively and accurately measured by the measured bending moment and curvature of the test hose.

  Hereinafter, an embodiment of a hose bending stiffness measuring device according to the present invention will be described with reference to the drawings. In the drawings to be referred to, FIG. 1 is a front view schematically showing the entire structure of a hose bending stiffness measuring device according to an embodiment, and FIG. 2 is a perspective view showing the structure of each part of the hose bending stiffness measuring device shown in FIG. 3 is a front view of the hose bending stiffness measuring apparatus shown in FIG. 2, and FIG. 4 is a side view of the hose bending stiffness measuring apparatus shown in FIG.

  The hose bending stiffness measuring device of one embodiment shown in FIGS. 1 to 4 is a device for measuring the bending stiffness of a test hose H such as a flexible rubber hose or resin hose, which is shown in FIG. In addition, the universal type tensile tester 1 is used to configure between the fixed base 1A and the crosshead 1B.

  This hose bending stiffness measuring device applies a bending load to the test hose H and the hose fixtures 3 and 3 for detachably fixing both ends of the test hose H to the pair of rotary disks 2 and 2. A pair of rotary disks 2 and 2 for rotating them in opposite directions, a crosshead 1B as a traction means for pulling the rope 4, and a traction load measuring means for the rope 4 The load cell 5 and an image processing device 6 as a rotation angle measuring means for measuring the rotation angle of the pair of rotary disks 2 and 2 are provided.

  Here, the support structure of the pair of rotary disks 2 and 2 will be described. A base plate 7 is fixed on the fixed base 1A of the universal tensile testing machine 1, and a pair of horizontally long front and rear supports 8, 8 are supported via a pair of left and right support columns 9, 9. A pair of front and rear guide rails 10 and 10 extending in the left-right direction are fixed in parallel to each other on the pair of front and rear racks 8 and 8, and a slider 11 is slidable on each guide rail 10. It is attached to. A bearing holder 12 is fixed on each slider 11, and a central shaft 2A of the rotary disk 2 extending in the front-rear direction is supported on each bearing holder 12 so as to be rotatable.

  With such a support structure, the pair of rotary disks 2 and 2 are supported by being offset in the front-rear direction with the distance between the center axes 2A and 2A being left and right. It is possible to approach the direction without interfering with each other. The rotary disks 2 and 2 are configured as pulleys that wind the cord 4 around the outer circumferential groove.

  A pair of hose fixtures 3 (only one is shown) is on a reference line connecting the centers of the rotary disks 2 and 2 on the opposed surfaces of the pair of rotary disks 2 and 2 that are offset left and right and arranged on the left and right. Are arranged at symmetrical positions. As shown in FIG. 5, the hose fixture 3 has an L-shaped bracket 3A in which one piece is fixed to the opposing surface of the rotary disk 2, and a nipple 3B fixed to the other piece in the L-shaped bracket 3A. Then, by fitting the end of the test hose H to the nipple 3B and fastening the fitting with a clip (not shown), both ends of the test hose H arranged on the reference line are detachably fixed. Is done.

  As shown in FIGS. 2 to 4, the cable body 4 is configured by a thin wire cable in which a thin steel wire is twisted, for example. The cable body 4 is fixed by appropriate means with both ends wound around the pair of rotary disks 2 and 2 in opposite directions, and an intermediate part thereof is paired with the pair of rotary disks 2 and 2. It is drawn upward from the inner part of the. The intermediate portion of the cable body 4 drawn upward is suspended from the load cell 5 via a tension jig 13, and the load cell 5 is fixed to the crosshead 1 B of the universal tensile testing machine 1. Yes.

  The tension jig 13 includes a support block 13A that is rotatably connected to the lower portion of the load cell 5 around the vertical axis, and a pair of arms 13B and 13B whose upper end is rotatably connected to the support block 13A around the horizontal axis. And a laterally extending tension roller 13C supported at both ends rotatably around the horizontal axis between the lower ends of the pair of arms 13B, 13B.

  The intermediate portion of the cable body 4 drawn upward from the inner portions of the pair of rotary disks 2 and 2 wraps around and supports the upper surface of the tension roller 13C of the tension jig 13 so that there is no stress concentration. Has been. Then, when the tension roller 13C moves upward in accordance with the upward movement of the cross head 1B, the intermediate portion of the cable body 4 causes the pair of rotary disks 2 and 2 to be opposite to each other via both ends of the cable body 4. It is configured to rotate in a balanced manner.

  The image processing apparatus 6 shown in FIG. 1 includes a CCD camera 6A that can output data to a personal computer PC for data processing. The CCD camera 6A observes a change in the distance between them by, for example, imaging a pair of marked markers M, M shown in FIG. That is, the change in the distance between the central axes 2A and 2A of the pair of rotary disks 2 and 2 is observed from the change in the distance between the pair of bearing holders 12 and 12 provided with the marked markers M and M.

  The CCD camera 6 </ b> A measures the rotational angle of the rotary disk 2 by observing, for example, the change in the angle of the line mark L provided on one rotary disk 2.

  In the hose bending stiffness measuring apparatus of one embodiment configured as described above, when the crosshead 1B gradually rises with the operation of the universal tensile testing machine 1 shown in FIG. 1, the load cell fixed to the crosshead 1B. 5, the tension roller 13 </ b> C of the tension jig 13 rises. Along with this, the intermediate portion of the rope body 4 is pulled upward, so that the pair of rotary disks 2 and 2 rotate in opposite directions with good balance via both ends of the rope body 4. A bending load acts on the test hose H whose both ends are fixed to the pair of rotary disks 2 and 2 via the pair of hose fixtures 3 and 3.

  At that time, the traction load (tension) T of the cable body 4 is measured by the load cell 5, and the test hose H is determined by the traction load (tension) T and the effective radius r of the rotary disk 2 around which the cable body 4 is wound. The bending moment Mθ acting on is measured as Mθ = Tr.

  In this measurement of the bending moment Mθ of the test hose H, it is assumed that the frictional force between the cable body 4 and the rotary disks 2 and 2 is extremely small compared to the traction load (tension) T. Ignore it. Further, the horizontal component force acting between the rotary disks 2 and 2 is ignored because the distance from the rotary disks 2 and 2 to the tension roller 13C is sufficiently long.

  On the other hand, the rotation angle of the rotary disk 2 is measured from the change in the angle of the line mark L observed by the CCD camera 6A of the image processing device 6, and the curvature of the test hose H is determined based on the rotation angle of the rotary disk 2. Measured. Then, the bending rigidity of the test hose H having flexibility is objectively and accurately measured by the measured bending moment Mθ and curvature of the test hose H.

  Note that the rotation angle of the rotary disk 2 may be calculated from the pull-out amount of the cord body 4 estimated from the movement amount of the crosshead 1B and the effective radius r of the rotary disk 2.

  Thus, according to the hose bending stiffness measuring apparatus of one embodiment, the bending stiffness of the test hose H having flexibility is objectively determined by the measured bending moment Mθ and curvature of the test hose H, and Can be measured accurately.

  The hose bending stiffness measuring device according to the present invention is not limited to the above-described embodiment. In the said embodiment, although it was set as the structure which pulls up the cable body 4 upwards, it is good also as a structure which pulls down the cable body 4 conversely. Further, for example, the towing means for towing the cord body 4 may be constituted by a weight W having a known weight, as shown in FIGS. In this case, one end of the pair of cords 14, 14 is wound around the pair of rotary disks 2, 2 in opposite directions and fixed to the other end of the pair of cords 14, 14. The weights W, W are suspended.

  The pair of rotary disks 2 and 2 can be provided with an angle scale and an encoder as the rotation angle measuring means, and a torque gauge in place of the load cell 5 can be attached.

  Furthermore, a scale S for measuring the distance between the central axes 2A and 2A of the pair of rotary disks 2 and 2 can be appropriately attached to the front frame 8 as necessary. If a displacement meter capable of outputting an electrical signal such as a linear gauge or digital caliper is attached in place of the scale S, the distance between the central axes 2A and 2A of the pair of rotary disks 2 and 2 can be measured in real time.

  Further, the load cell 5 as the traction load measuring means can be changed to a spring balance, a push-pull gauge or the like.

It is a front view showing roughly the whole structure of the hose bending rigidity measuring device concerning one embodiment of this invention. It is a perspective view which shows the structure of each part of the hose bending rigidity measuring apparatus shown in FIG. It is a front view of the hose bending rigidity measuring apparatus shown in FIG. It is a side view of the hose bending rigidity measuring apparatus shown in FIG. FIG. 3 is a partial perspective view showing an enlarged structure near a rotary disk shown in FIG. 2. FIG. 6 is a partial perspective view showing a modification of the structure near the rotary disk shown in FIG. 5. FIG. 7 is a front view of the structure near the rotary disk shown in FIG. 6.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Universal type tensile tester 1A Fixing base 1B Cross head 2 Rotary disk 3 Hose fixture 4 Cable body 5 Load cell 6 Image processing device 6A CCD camera 7 Base plate 8 Mounting base 9 Strut 10 Guide rail 11 Slider 12 Bearing holder 13 Pulling jig 13C Tension roller H Test hose W Weight PC Personal computer

Claims (7)

An apparatus for measuring the bending rigidity of a flexible test hose,
A pair of rotary disks supported so as to be able to contact and separate from each other in a direction between the axes from a state in which the distance between the axes is separated;
A pair of hose fixtures for fixing both ends of the test hose to the symmetrical position of the side surface of each rotary disk on the center line passing through the axis of each rotary disk;
A cord body whose ends are wound in opposite directions with respect to the pair of rotary disks and fixed,
Pulling means capable of pulling the cord so as to rotate the pair of rotary disks in opposite directions;
Traction load measuring means for measuring the traction load of the cable body;
A hose bending stiffness measuring device comprising a rotation angle measuring means for measuring a rotation angle of the pair of rotary disks.   The hose bending stiffness measuring apparatus according to claim 1, wherein the pulling means is constituted by a cross head of a universal tensile testing machine.   2. The hose bending stiffness measuring device according to claim 1, wherein the pulling means comprises a weight having a known weight.   4. The hose bending according to claim 2, wherein the traction load measuring means is configured by a load cell, and a crosshead or a weight is configured to pull the cable body through the load cell. Stiffness measuring device.   The hose bending stiffness measuring device according to any one of claims 1 to 4, wherein an angle scale is attached to the pair of rotary disks as the rotation angle measuring means.   The hose bending stiffness measuring device according to any one of claims 1 to 4, wherein an encoder is attached to the pair of rotary disks as the rotation angle measuring means.   The hose bending stiffness measuring device according to any one of claims 1 to 6, wherein a torque gauge instead of the traction load measuring means is attached to the pair of rotary disks.

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