JP2011099829A - Test piece, abrasion fatigue tester using the same, and abrasion fatigue test method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a test piece preventing breaking at a chuck part during a period of an abrasion fatigue test of a thin line. <P>SOLUTION: This test piece 1 holding both ends (chuck parts) 3 of a test line 2, for performing an abrasion fatigue test by applying repeated stress amplitude to the center part of the test line 2 under a contact condition includes: the test line 2 formed to have a prescribed length; and a protection tape 4 formed sharply from the chuck part 3 side to the test part A side, for sandwiching a part other than the test part A of the test line 2 so as to protect a part of the test line 2 excluding the center test part A forming a contact part of the test line 2. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a test piece for performing a wear fatigue test on a thin test wire, a wear fatigue test apparatus using the test piece, and a wear fatigue test method.

  In order to improve the bending resistance of the cable, a stranded wire obtained by twisting a plurality of thin wires (thin wire rods) is used as a cable conductor. In twisted wires, adjacent thin wires are in contact with each other, and it has been found that when the cable is bent, a contact load is generated between the thin wires at the bent portion, and the wire breaks earlier than expected. .

  There is a fretting test as a fatigue test method assuming contact load. However, it is difficult to apply the fretting test method of steel for measuring the life of stranded wire because the thin wire is too thin. There is no example of a tensile test (hereinafter referred to as a wear fatigue test) under the above contact (wear) conditions.

  In general, in a fretting test of steel (for example, a metal plate material), a test piece in which a large chuck portion is formed at both ends of a small-width test portion is used. The test is performed by holding and applying a repeated stress amplitude and applying a contact load to the test part. In this way, in the fretting test of the steel material, cutting at a narrow test portion is ensured, and an accurate test result can be obtained.

  On the other hand, in the tensile test of the thin wire, it was difficult to process because the thin wire as the test material was too thin, so both ends (chuck part) of the thin wire were held as they were without applying special processing to the thin wire Then, the test was conducted by pulling.

  However, when the thin wire is held on the chuck of the test device as it is, the cross-sectional shape changes due to the gripping force applied to the chuck part, stress concentration occurs in the chuck part, and it is cut at that part. It was difficult to do.

  Conventionally, as a method for solving this problem, a method of forming a coating layer for preventing cutting from a chuck portion of a thin wire has been proposed (for example, see Patent Document 1).

JP-A-54-20787 JP-A-9-264830 Japanese Unexamined Patent Publication No. 64-46739 JP-A-6-18380

  However, even when a coating layer is formed on the chuck, stress concentration occurs at the boundary between the thin wire portion covered with the coating layer and the exposed thin wire portion because the rigidity of the coating layer is different from that of the fine wire. However, it may be cut from the boundary portion.

  As described above, in the conventional method, the thin line is cut at a portion other than the test portion, and there is a problem that an accurate test result cannot be obtained and a test with good reproducibility cannot be performed.

  Further, as described above, a tensile test under the condition of contact (abrasion) of fine wires has not been proposed yet.

  Accordingly, an object of the present invention is to provide a test piece capable of performing a tensile test under a contact (abrasion) condition of a thin wire, that is, a wear fatigue test, a wear fatigue test apparatus using the test piece, and a wear fatigue test method. is there.

  The present invention was devised to achieve the above-described object, and is for holding a both ends of a test line and performing a wear fatigue test by applying a repeated stress amplitude to the center of the test line under contact conditions. In the test piece, a portion of the test line other than the test portion is protected so as to protect a portion of the test line excluding a test line formed to a predetermined length and a central test portion which is a contact portion of the test line. It is a test piece provided with a protective tape that is sandwiched and sharply formed from both ends to the test part.

  The protective tape may have an adhesive surface on one side and be provided so as to sandwich the test line between the adhesive surfaces.

  It is preferable that both ends of the test line are sandwiched in advance by a reinforcing tape and further sandwiched by the protective tape from above the reinforcing tape.

  The protective tape is preferably made of a polyimide film.

  The length of the test part may be 1/4 to 1/2 of the total length of the test line, and the sharp angle of the protective tape may be 20 ± 10 °.

  The present invention also provides the test piece, a fixed chuck that holds one end of the test piece, a movable chuck that is disposed to face the fixed chuck and holds the other end of the test piece movably, and the fixed A load cell attached to the chuck, and slide means for sliding the movable chuck in the longitudinal direction of the test piece, changing an arrangement interval between the fixed chuck and the movable chuck, and repeatedly applying stress amplitude to the test piece. A wear fatigue test apparatus comprising contact load applying means for applying a contact load to the test portion of the test piece.

  The contact load applying means is inserted between the upper pulley and the lower pulley arranged above and below the test section, and crossed between the upper pulley and the lower pulley so as to pass through the test section. A contact line that has an opening intersection and is respectively wound around the lower pulley in a crossed state; a fixing portion that fixes one end of the contact line wound around one of the lower pulleys; and the other of the lower pulley A weight attached to the other end of the contact line wound around the contact line, a predetermined tension is applied to the contact line by the fixed part and the weight, and the test part is formed at an opening intersection of the contact line. A predetermined contact load may be applied to the test portion by sandwiching the test portion.

  Further, the present invention provides a method in which both end portions of the test piece are respectively held by chucks, and a contact load is applied to the test portion of the test piece. This is a wear fatigue test method in which a wear fatigue test is performed.

  According to the present invention, it is possible to perform a tensile test, that is, a wear fatigue test under the condition of contact (wear) of fine wires.

It is a figure which shows the test piece which concerns on one embodiment of this invention. It is a figure which shows the abrasion fatigue test apparatus which concerns on one embodiment of this invention. It is a figure which shows an example of the measurement result by this invention.

  Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a view showing a test piece according to the present embodiment.

  As shown in FIG. 1, the test piece 1 according to the present embodiment holds both end portions (chuck portions) 3 of the test line 2 and repeats the stress amplitude at the center portion of the test line 2 under contact (wear) conditions. The test line 2 except for the test line 2 formed to a predetermined length and the central test part A that is the contact part of the test line 2 is protected. Accordingly, a portion other than the test portion A of the test line 2 is sandwiched, and the protective tape 4 is formed in a sharp shape from the chuck portion 3 side to the test portion A side.

  The test wire 2 is a thin wire made of a tin-copper alloy having a diameter of 1.0 mm or less (in this embodiment, 0.08 mm), for example.

  The protective tape 4 includes a rectangular base portion 4a, and an isosceles triangular stress relief portion 4b formed integrally with the base portion 4a and provided between the chuck portion 3 and the test portion A. The test part A is provided so as to be exposed from the apex angle part 4c at the tip of the stress relaxation part 4b.

  The protective tape 4 has an adhesive surface 5 on one side, and is provided so that the test line 2 is sandwiched between the adhesive surfaces 5. As the protective tape 4, a material that does not extend beyond the test line 2, for example, a Kapton (registered trademark) tape made of a polyimide film may be used. If a protective tape 4 that extends beyond the test line 2 is used, a part other than the test part A of the test line 2 contributes to the test result, and an accurate test becomes difficult. Therefore, the protective tape 4 is preferably made of a material having a smaller elongation than the test line 2.

  The chuck portion 3 of the test line 2 is sandwiched in advance with the reinforcing tape 6 and fixed with the instantaneous adhesive 7, and then further sandwiched between the reinforcing tape 6 and the base portion 4 a of the protective tape 4. The reinforcing tape 6 reinforces the chuck portion 3 and prevents the test line 2 from slipping to make it easier to hold the chuck portion 3.

  Since the reinforcing tape 6 is used to facilitate the holding of the chuck portion 3, the protective tape 4 can be provided without providing the reinforcing tape 6 as long as the chuck portion 3 can be held without providing the reinforcing tape 6. It is good only as well.

  The protective tape 4 and the reinforcing tape 6 can improve the handleability of the thin test wire 2 and facilitate the work such as leveling the test wire 2.

  In the present embodiment, the length of the test part A is 50 mm, the length between the chuck parts 3 is 130 mm, the width of the protective tape 4 is 13 mm, and the sharp angle of the protective tape 4 is 18.5 °. The length of the test part A is preferably ¼ to ½ of the total length of the test line 2 and the sharp angle of the protective tape 4 is preferably 20 ± 10 °. The reason for this will be described later.

  A wear fatigue test method using this test piece 1 will be described.

  First, a wear fatigue test apparatus used for the wear fatigue test method will be described.

  As shown in FIG. 2, the wear fatigue test apparatus 10 according to this embodiment includes a test piece 1, a fixed chuck 11 that holds one end (one chuck portion 3) of the test piece 1, and the fixed chuck 11. The movable chuck 12 movably holds the other end (the other chuck portion 3) of the test piece 1, the load cell 13 attached to the fixed chuck 11, and the movable chuck 12 in the longitudinal direction of the test piece 1. The sliding means 14 for repeatedly applying a stress amplitude to the test piece 1 by changing the arrangement interval between the fixed chuck 11 and the movable chuck 12 and applying the contact load to the test part A of the test piece 1 Means 15.

  Here, the movable chuck 12 does not operate the chuck itself but is operated by the slide means 14 described above, and does not indicate that the chuck itself operates.

  The load cell 13 detects a tensile load applied to the test piece 1. Based on this detected value, the slide width or tensile force of the slide means 14 is controlled.

  The slide means 14 is composed of, for example, an electric actuator (electric slider). This slide means 14 slides (repetitive movement) with a predetermined slide width in the longitudinal direction of the test line 2 based on the detection value of the load cell 13 and at a predetermined repeated tensile load frequency (5.5 Hz in this embodiment). A tensile load is applied to the test piece 1.

  The contact load applying means 15 is crossed between the upper pulley 16 and the lower pulley 17 that are arranged above and below the test section A, and the upper pulley 16 and the lower pulley 17 so as to cross the test section A. A contact line 19 having an opening intersection 18 to be inserted and wound around the lower pulley 17 in a crossed state; and a fixing portion 20 for fixing one end of the contact line 19 wound around one of the lower pulleys 17; And a weight 21 attached to the other end of the contact line 19 wound around the other of the lower pulley 17.

  As the contact wire 19, the stranded wire is usually a twist of the same type of fine wire, so it is good to use the same one as the test wire 2 simulating the implementation environment, but is not limited to this. The type of the contact line 19 can be appropriately selected according to the implementation environment.

  The contact load applying means 15 applies a predetermined tension to the contact line 19 by the fixing part 20 and the weight 21, sandwiches the test part A at the opening intersection 18 of the contact line 19, and applies a predetermined contact load to the test part A. It is given. The contact load can be changed by appropriately selecting the weight 21.

  Next, a wear fatigue test method using the wear fatigue test apparatus 10 will be described.

  After preparing the test piece 1 and fixing the chuck portion 3 to the fixed chuck 11 and the movable chuck 12, respectively, the contact line 19 is wound so as to intersect between the upper pulley 16 and the lower pulley 17, and the intersection is made. Set so that the test part A is inserted through the opening intersection 18.

  Thereafter, one end of the contact line 19 is fixed to the fixing portion 20 and a weight 21 is attached to the other end. Thereby, a predetermined tension is applied to the contact line 19 to apply a contact load to the test part A.

  In this state, the actuator as the sliding means 14 is driven to repeatedly apply a stress amplitude to the test line 2. At this time, the detected value of the load cell 13 is always fed back to the actuator, and the slide width or tensile force is adjusted so that a predetermined tensile load is detected by the load cell 13.

  In this state, the number of times the test part A breaks (the life is reached) is counted. Detection of breakage is performed by the load cell 13. That is, when no load is detected by the load cell 13, it is determined that the test line 2 is broken, and the number of slides when the load is broken is defined as the life.

  Thus, in the present invention, since the test piece 1 is configured by providing the protective tape 4 formed sharply on both sides including the chuck part 3 of the test line 2, the chuck part 3 side of the test line 2 is provided. The rigidity gradually changes from the test part A to the test part A, and the test can be performed while preventing (relaxing) stress concentration from occurring in the apex part 4c of the protective tape 4 during the wear fatigue test. Therefore, the test line 2 is cut at the center side of the test part A during the test, and an accurate test can be performed.

  The reason why the length of the test part A is preferably ¼ to ½ of the total length of the test line 2 and the sharp angle of the protective tape 4 is preferably 20 ± 10 ° is as follows. This is because if the portion to be protected becomes longer, the influence of slight bending of the tape becomes larger and the test wire 2 may be bent. In addition, if the sharp angle of the protective tape 4 is large, the change in rigidity cannot be sufficiently smoothed. If the sharp angle is small, the surface area of the protective tape 4 is small and the cutting at the chuck portion 3 is sufficiently prevented. It is because it is not possible.

  An example of the results of the wear fatigue test of the present invention is shown in FIG.

  As shown in FIG. 3, the life is shortened as the contact load is increased and the tensile load is increased as compared with simple tension, that is, when the contact line 19 is not provided.

  Thus, it can be seen that the wear fatigue life of the test line 2 of φ1.0 mm or less, which was difficult in the conventional tensile test method, can be evaluated by the wear fatigue test method of the present invention.

  In short, according to the present invention, it is possible to perform a tensile test under the contact (wear) condition of thin wires, that is, a wear fatigue test.

  Further, according to the present invention, even a thin test line 2 having a diameter of 1.0 mm or less can be applied with a contact load by the contact line 19 without causing bending strain on the test line 2.

  Furthermore, the repeated tensile strain (tensile load) applied to the test line 2 and the contact load applied by the contact line 19 can be controlled independently, and the test can be performed by changing each parameter as desired.

1 Test piece 2 Test line 3 Chuck part 4 Protective tape A Test part

Claims (8)

In a test piece for holding the both ends of the test line and performing a wear fatigue test by repeatedly applying a stress amplitude to the center of the test line under contact conditions,
A test line formed to a predetermined length;
A portion other than the test portion of the test line is sandwiched to protect the portion of the test line excluding the central test portion that becomes the contact portion of the test line, and formed sharply from both ends to the test portion. A test piece comprising a protective tape.   The test piece according to claim 1, wherein the protective tape has an adhesive surface on one side and is provided so as to sandwich the test line between the adhesive surfaces.   The test piece according to claim 1 or 2, wherein both ends of the test line are sandwiched in advance by a reinforcing tape and further sandwiched by the protective tape from above the reinforcing tape.   The test piece according to claim 1, wherein the protective tape is made of a polyimide film.   The length of the said test part is made into the length of 1/4 to 1/2 of the full length of the said test line, and the acute angle of the said masking tape shall be 20 +/- 10 degrees. The test piece as described. The test piece according to any one of claims 1 to 5,
A fixed chuck for holding one end of the test piece;
A movable chuck disposed opposite to the fixed chuck and movably holding the other end of the test piece;
A load cell attached to the fixed chuck;
Slide means for sliding the movable chuck in the longitudinal direction of the test piece, changing an arrangement interval between the fixed chuck and the movable chuck, and applying a repeated stress amplitude to the test piece;
A wear fatigue test apparatus comprising contact load applying means for applying a contact load to the test portion of the test piece. The contact load applying means is
An upper pulley and a lower pulley arranged above and below the test section;
A contact line that is passed over the upper pulley and has an opening intersection that passes through the test section and intersects the lower pulley, and is wound around the lower pulley in a crossed state;
A fixing portion for fixing one end of the contact line wound around one of the lower pulleys;
A weight attached to the other end of the contact line wound around the other of the lower pulley, and a predetermined tension is applied to the contact line by the fixing portion and the weight, and an opening intersection of the contact line The wear fatigue test apparatus according to claim 6, wherein the test part is sandwiched between the test part and a predetermined contact load is applied to the test part.   The both ends of the test piece according to any one of claims 1 to 5 are each held by a chuck, and the test interval is changed by changing the arrangement interval of the chuck in a state where a contact load is applied to the test portion of the test piece. A wear fatigue test method characterized by applying a repeated stress amplitude to a piece and performing a wear fatigue test.

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