JP5327132B2 - Wear test apparatus and wear test method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus and a test method for conducting wear tests in a point-contact state at a constantly stable revolution speed and contact position without being affected by the material or the surface conditions of a specimen, test conditions, etc. which is capable of evaluating wear resistance with high repeatability. <P>SOLUTION: A wear test apparatus comprises: a first rotation shaft which is driven to rotate by a motor; a second rotation shaft which detachably holds a ball member in cooperation with the first rotation shaft; a specimen holder which holds a specimen; a specimen holder biasing part which biases the specimen holder to the ball member so as to press the specimen to the ball member; and time control means which drives the motor according to a predetermined test time. The first rotation shaft and the second rotation shaft hold the ball member with a load greater than that applied when the specimen presses the ball member and rotate the ball member to abrade a surface of the specimen. <P>COPYRIGHT: (C)2012,JPO&amp;INPIT

Description

  The present invention provides a wear test apparatus and a wear test method. Particularly, it is possible to use, as a replacement part, a steel ball in which an inexpensive mass-produced product circulates, and it requires skill to operate the test apparatus. A wear test apparatus and a wear test method capable of performing a wear test with high reproducibility are provided.

Many industrial products are subjected to wear testing for quality inspection in the development stage or in the manufacturing process. As the contact form of the wear test, many point contact and line contact tests that are likely to have a high surface pressure are performed. For example, a lubrication wear test and a micro abrasive wear test are performed as conventional techniques.

For example, in Patent Document 1, as a lubrication and wear test apparatus, a test piece is pressed from below onto a roll-shaped rotating body fixed to the tip of a rotating shaft installed in a rotary drive device, and the rotating body is rotated. Describes a wear test apparatus for inspecting the wear of a test piece.

Further, as shown in FIG. 1, Non-Patent Document 1 discloses a micro-abrasive wear test apparatus, as shown in FIG. 1, a test piece (Specimen) installed with an inclination and a drive shaft (Drive Shaft) installed in a rotary drive apparatus ) Holds the steel ball (Rotating sphere), the friction between the drive shaft and the steel ball causes the rotation of the drive shaft to be transmitted to the steel ball, and the steel ball rotates to wear the specimen. Is described.

JP 58-225342 A (1 page, Fig. 2)

"A micro-abrasive wear test, with particular application to coated systems" by L.Lutherford and I.M.Hutchings, published in 1996, published in Journal 79 of Surface and Coatings Technology (pages 231 to 239, Fig. 2)

  However, since the lubricating wear test apparatus described in Patent Document 1 is in a state where only one side of the rotating body is supported by the rotating shaft, the larger the load, the more the rotating shaft will bend and the contact position may move. There is. On the other hand, when the surface of the rotator is flattened and line contact is made, the contact area increases as compared to point contact, so that the surface pressure decreases and the test may take a long time. Moreover, the thing of patent document 1 also has the problem that the manufacturing / procurement cost of the rotary body which is a consumable part is high since the rotary body has a ring-shaped special shape.

  Moreover, although the micro abrasive wear test apparatus described in Non-Patent Document 1 can use a steel ball as a consumable part, the steel ball is only placed on a test piece provided with an inclination. The rotational speed of the steel ball is likely to fluctuate due to the friction between the steel ball and the drive shaft or the steel ball and the test piece. For example, it is conceivable that the rotation speed of the steel ball fluctuates due to the change in the coefficient of friction between the test piece and the steel ball during the wear of the test piece. It was difficult to conduct a high wear test.

  The present invention has been made to solve the above problems, and is not affected by the material, surface state, or test conditions of the test piece, and is always subjected to a wear test at a stable rotational speed and contact position in a point contact state. A wear test apparatus and a wear test method capable of performing wear resistance evaluation with high reproducibility are provided. It is another object of the present invention to provide a wear test apparatus and a wear test method that are simple in operation and that can use inexpensive steel balls for replacement parts.

  A wear test apparatus according to the present invention includes a first rotating shaft that is rotationally driven by a motor, a second rotating shaft that detachably holds a spherical member in cooperation with the first rotating shaft, and a test piece. A test piece holder to be held, a test piece holder urging portion that presses the test piece against the spherical member by urging the test piece holder toward the spherical member, and the motor is set. Time control means for driving according to a test time, and the first rotating shaft and the second rotating shaft sandwich the spherical member with a load larger than a load with which the test piece presses the spherical member. Then, the spherical member is rotated to wear the surface of the test piece.

  The wear test apparatus according to the present invention is hardly affected by the material, surface condition, test conditions, or the like of the test piece, and can slide at a stable rotational speed and contact position to perform a highly reproducible wear test.

It is a schematic diagram of the conventional micro abrasive wear test. (K.L.Lutherford, I.M.Hutchings, "A micro-abrasive wear test, with particular application to coated systems", Surface and Coatings Technology, Vol. 79, 1996, pp. 231-239, Fig. 2) 1 is a cross-sectional view showing a wear test apparatus according to Embodiment 1 of the present invention. FIG. 5 is a cross-sectional view showing a main part of a wear test apparatus according to Embodiment 2 of the present invention. FIG. 6 is a cross-sectional view showing a main part of a wear test apparatus according to Embodiment 3 of the present invention.

Embodiment 1 FIG.
FIG. 2 is a cross-sectional view of the wear test apparatus according to Embodiment 1 of the present invention. In the wear test apparatus in the present embodiment, a steel ball 9 that is a spherical member is detachably sandwiched between a first rotating shaft 11 and a second rotating shaft 12, and the test piece 1 is pushed against the rotating steel ball 9. The wear resistance of the test piece 1 is evaluated by applying circular wear marks on the surface of the test piece.

  The configuration of the wear test apparatus shown in FIG. 2 will be described. The test piece 1 is held by a test piece holder 2, and a load cell 3 for measuring a load between the test piece 1 and the steel ball 9 is provided below the test piece holder 2. The load cell 3 is held by a load cell receiver 4, and a lower end portion of the load cell receiver 4 is inserted into a through hole of the outer cylinder 6. The lower end portion of the load cell receiver 4 is inserted from the upper opening portion of the through hole, the lower opening portion is a female screw portion, the screw 5 is inserted, and is fixed to the outer cylinder 6 by the nut 8. . Inside the through hole of the outer cylinder 6, a coil spring 7 (test piece holder biasing portion) is inserted in a compressed state between the load cell receiver 4 and the screw 5, and due to the repulsive force of the coil spring 7, The load cell receiver 4 is biased upward, that is, toward the steel ball 9. The test piece holder 2 is urged upward by the load cell receiver 4 via the load cell 3 and presses the test piece 1 placed on the test piece holder 2 against the steel ball 9.

  The steel ball 9 is arranged on the upper part of the test piece 1 and is detachably held between the first rotating shaft 11 and the second rotating shaft 12. More specifically, a concave portion that has a curvature equivalent to that of the steel ball 9 and engages with the steel ball 9 is used as a tray for the steel ball 9 at the opposing end portions of the first rotating shaft 11 and the second rotating shaft. The steel balls 9 are formed and sandwiched by the trays of the rotary shaft 11 and the rotary shaft 12 with the axes of the rotary shafts aligned. The rotating shaft 11 is rotated by the motor 10, and the rotating shaft 12 rotates in the same manner as the rotating shaft 11 due to the rotational force transmitted from the rotating shaft 11 through the steel ball 9. The rotating shaft 11 and the rotating shaft 12 are supported by a bearing 14 and a bearing 15, respectively.

  A coil spring 13 is wound around the rotary shaft 12, and the steel ball 9 is pressed against the rotary shaft 11 using an axial spring load by the coil spring 13. At this time, the spring load by the coil spring 13 is set to be larger than the load when the test piece 1 presses the steel ball 9. As a result, even when the friction coefficient between the test piece 1 and the steel ball 9 changes due to the change in the surface condition due to the material of the test piece 1 and the progress of wear, the holding force of the rotating shafts 11 and 12 with respect to the steel ball 9 is maintained. Since it is larger than the frictional force between 1 and the steel ball 9, it is possible to always perform a wear test at a stable rotational speed without being affected by the changing frictional force.

  When the hardness of the surface of the test piece 1 is higher than that of the steel ball 9 and the hardness difference between the steel ball 9 and the test piece 1 is large, the surface of the test piece 1 is not easily worn. By applying the abrasive 18 to the sliding surface, the wear of the test piece 1 can be accelerated.

  The load measured by the load cell 3 is displayed on a display device (not shown). The operator of the test apparatus can adjust the load with which the test piece 1 presses the steel ball 9 by adjusting the amount of insertion of the screw 5 into the through hole of the outer cylinder 6 based on this measured value. Further, the rotation speed and rotation time of the motor 10 are controlled by the rotation speed control device 16 and the time control device 17. The target rotational speed and target rotational time of the motor 10 are input to the rotational speed control device 16 and the time control device 17 by an operator using an input device (not shown).

  Next, a wear test method using the wear test apparatus shown in FIG. 2 will be described. First, the interval between the two rotating shafts 11 and the rotating shafts 12 is widened by pulling the rotating shaft 12 having the coil springs 13 in the direction against the spring load (to the right in the drawing of FIG. 2). Next, the steel ball 9 is sandwiched between the rotary shaft 11 and the rotary shaft 12 by inserting the steel ball 9 between the rotary shaft 11 and the rotary shaft 12 in a state in which the axis is aligned with the rotation center of the motor 10. . Next, the abrasive 18 is applied to the steel ball 9, the test piece 1 is fixed to the test piece holder 2, the test piece holder 2 is pushed up by the screw 5, and the test piece 1 is placed under the steel ball 9 with an arbitrary load. Then, the screw 5 is fixed using the nut 8. The load at this time is measured by the load cell 3.

Thus, with the test piece 1 and the steel ball 9 in contact with each other, the rotational speed of the steel ball 9 and the test time are set to arbitrary conditions using the rotational speed control device 16 and the time control device 17 connected to the motor. Set and start the test. After the test, the wear resistance of the test piece 1 can be quantitatively evaluated by measuring the size of the circular wear scar generated on the surface of the test piece 1.

The test piece 1 to be evaluated is not particularly limited as long as the evaluation method according to the present invention can be applied. For example, parts of home appliances, parts of vehicles such as automobiles, parts of machines other than vehicles, molded parts Examples include a mold such as a metal mold, a part such as a cutting tool and a jig, and a specimen that can correspond to a part related to wear resistance evaluation. Examples of the material of the test piece 1 include carburized and hardened steel, high-speed tool steel, and die steel.

Moreover, even if the test piece 1 forms the film in at least one part of the surface, if the evaluation method concerning this invention is applicable, there will be no special restriction | limiting. For example, a film having a thickness of about 1 to 3 μm and a hardness higher than that of the substrate may be applied as an abrasion-resistant film that improves the wear resistance of the substrate. Examples of the wear resistant film include carbides, nitrides and carbonitrides containing titanium, chromium, aluminum, and tungsten, and hard carbon films (DLC films: Diamond-Like-Carbon films).

Examples of the carbide include titanium carbide (TiC) and tungsten carbide (WC). Examples of the nitride include titanium nitride (TiN), aluminum nitride (AlN), and chromium nitride (CrN). Specific examples of the carbonitride include titanium carbonitride (TiCN). Further, a film in which two or more of these carbides, nitrides, and carbonitrides are stacked may be used. Specific examples of the multilayer film include a combination of hard films such as TiC / TiN, AlN / CrN, and TiCN / TiC.

The material of the steel ball 9 may be any material (typically a metal material) that can evaluate the wear resistance of the test piece 1. Specifically, as an example, a bearing steel ball of SUJ2 (high carbon chromium steel) is used. Can be mentioned. Since the diameter, grade, etc. of the bearing steel ball are determined by JIS, it is possible to suppress variations in wear support due to the bearing steel ball by using a highly accurate bearing steel ball. For example, it is preferable to use a bearing steel ball with higher accuracy than 60 grade. Also, there is no special restriction on the diameter of the steel ball, but when the test is performed at the same sliding distance, the smaller the diameter, the faster the wear of the sliding surface of the steel ball proceeds, so a larger diameter is preferable. .

The pressing load of the test piece 1 on the steel ball 9, the number of revolutions of the steel ball 9, and the test time are not particularly limited unless a film is formed on the surface of the test piece 1. On the other hand, when forming a coating and evaluating the wear resistance of the coating, it is necessary to set conditions so that the substrate is not worn.
The abrasive 18 applied to the sliding surface of the test piece 1 and the steel ball 9 is not particularly limited as long as the evaluation method according to the present invention can be applied. For example, diamond paste, diamond, cubic boron nitride And a slurry containing silicon carbide particles. These particle sizes are not particularly limited as long as they can be applied to the abrasion resistance evaluation of the test piece 1, but examples thereof include 1 μm and 3 μm that can be obtained at a lower price as the particle size is smaller. Moreover, the place which apply | coats the abrasive | polishing agent 18 may be one place or multiple places. When the abrasive 18 is applied to the sliding surface at a plurality of intervals, the abrasive 18 is likely to spread over the entire sliding surface.

As described above, in the wear test apparatus according to the present embodiment, the rotating shaft 11 that is installed in the motor 10 and has a saucer at the end, the saucer similar to the rotating shaft 11, and the coil spring 13 is wound around. The rotary shaft 12 is supported by a bearing, and the rotary shafts 11 and 12 are used to fix the shaft by using a spring load larger than the test load of the coil spring 13 while aligning the shaft center with the rotation center of the motor 10. While pressing the test piece 1 against the steel ball 9, the steel ball 9 is rotated at a predetermined number of revolutions to cause one point on the surface of the test piece 1 to slide and wear. For this reason, it is possible to use a steel ball 9 in which inexpensive mass-produced products are distributed as a replacement part, and it is possible to perform a highly reproducible wear test without requiring skill in operation of the test apparatus. .

In particular, with this configuration, the rotational speed of the steel ball 9 can be adjusted even if the friction coefficient between the test piece 1 and the steel ball 9 changes due to changes in the material of the test piece 1 and the surface condition due to the progress of wear. Since the force for holding the steel ball 9 by 11 and 12 is larger than the friction force between the test piece 1 and the steel ball 9, it is always not affected by the change in the friction coefficient between the test piece 1 and the steel ball 9. It becomes possible to perform a wear test at a stable rotational speed. Furthermore, since the steel ball 9 is supported at both ends, the bending rigidity of the rotating shaft is increased, and the contact position between the test piece 1 and the steel ball 9 is not shifted during the test, and a wear test at a stable contact position can be performed. It becomes possible. As described above, since the wear test can be performed at a stable rotational speed and contact position, wear evaluation with high reproducibility is possible.

  In addition, the wear test apparatus according to the present embodiment includes a time control device 17 that controls the rotation time of the motor 10, and the motor 10 is automatically stopped when a preset time test is performed. Therefore, the test time is accurately controlled. Therefore, variation in the results of the wear test depending on the test time is suppressed, and wear evaluation with higher reproducibility can be performed.

  Further, in the wear test method according to the present embodiment, by pulling the rotating shaft 12 having the coil spring 13, the interval between the two rotating shafts 11, 12 is widened and the shaft core is aligned with the rotation center of the motor 10. In this state, the steel ball 9 is inserted between the rotary shafts 11 and 12, and the steel ball 9 is sandwiched between the rotary shafts 11 and 12 by the spring load of the coil spring 13, so that the steel ball 9 is attached to the rotary shafts 11 and 12. Fix against. Therefore, the worn steel ball 9 can be replaced with a relatively simple operation.

  In particular, by performing the evaluation according to the above-described procedure, it is possible to accurately slide and wear a predetermined distance at a stable rotational speed and contact position at all times. It is possible to evaluate the wear resistance even in the case where is required. Moreover, even when the hardness of the test piece 1 is higher than that of the steel ball 9, the abrasive 18 applied to the sliding surfaces of the test piece 1 and the steel ball 9 enables evaluation in a short time.

Embodiment 2. FIG.
FIG. 3 is a partial cross-sectional view of a wear test apparatus according to Embodiment 2 of the present invention. In the wear test apparatus in the present embodiment, a rubber 19 is interposed between the steel ball 9 and the rotating shaft 12, and the other points are the same as in the first embodiment.

  Since the holding force of the steel ball 9 by the rotating shafts 11 and 12 in FIG. 2 is larger than the test load, the rotation speed of the steel ball 9 is less affected by the frictional force between the test piece 1 and the steel ball 9. Yes. Since the rubber 19 is interposed between the rotating shaft 12 and the steel ball 9 as shown in FIG. 3, the frictional force between the steel ball 9 and the rotating shafts 11 and 12 becomes larger. Becomes larger and is less influenced by the frictional force between the test piece 1 and the steel ball 9.

Embodiment 3 FIG.
FIG. 4 is a partial cross-sectional view of a wear test apparatus according to Embodiment 3 of the present invention. In the wear test apparatus in the present embodiment, the abrasive 18 applied to the sliding portion between the test piece 1 and the steel ball 9 in the first embodiment is not applied. If the hardness of the test piece 1 to be evaluated is about the same as or less than that of the steel ball 9, it takes time, but it is possible to wear the test piece 1 without applying the abrasive 18 and perform a wear test. is there.

  1 Test piece, 2 Test piece holder, 3 Load cell, 4 Load cell receiver, 5 Screw, 6 Outer cylinder, 7 Coil spring, 8 Nut, 9 Steel ball, 10 Motor, 11 Rotating shaft, 12 Rotating shaft, 13 Coil spring, 14 Bearing, 15 Bearing, 16 Speed controller, 17 hour controller, 18 Abrasive, 19 Rubber.

Claims (7)

A first rotating shaft that is rotationally driven by a motor;
A second rotating shaft for removably holding the spherical member in cooperation with the first rotating shaft;
A specimen holder for holding the specimen;
A test piece holder urging portion that presses the test piece against the spherical member by urging the test piece holder toward the spherical member;
A time control means for driving the motor according to a set test time,
The first rotating shaft and the second rotating shaft sandwich the spherical member with a load larger than the load with which the test piece presses the spherical member, and rotate the spherical member to rotate the surface of the test piece. A wear test apparatus characterized in that a wear is made.   The second rotating shaft biases the spherical member with respect to the first rotating shaft, thereby detachably holding the spherical member in cooperation with the first rotating shaft. The wear test apparatus according to claim 1.   The wear test apparatus according to claim 1 or 2, wherein the spherical member is a bearing steel ball having a diameter and a grade defined by JIS standards.   The surface of the test piece is provided with an abrasion-resistant film having a hardness higher than that of the spherical member, and the spherical member is coated with an abrasive. Wear test equipment.   The wear test according to any one of claims 1 to 4, wherein the first or second rotating shaft has a concave portion that engages with the spherical member at an end portion on the spherical member side. apparatus.   The wear test apparatus according to claim 5, wherein rubber is interposed between the concave portion of the second rotating shaft and the spherical member.   The spherical member is sandwiched between a first rotating shaft that is rotationally driven by a motor and a second rotating shaft that removably clamps the spherical member in cooperation with the first rotating shaft, and a specimen holder Holding the test piece holder, and urging the test piece holder toward the spherical member by the test piece holder urging portion, thereby pressing the test piece against the spherical member and setting the motor. A wear test method for driving according to a test time, wherein the first rotating shaft and the second rotating shaft are configured to load the spherical member with a load larger than a load with which the test piece presses the spherical member. A wear test method comprising: sandwiching and rotating the spherical member to wear the surface of the test piece.

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