JPH03165232A - Friction and wear testing device - Google Patents

Abstract

PURPOSE:To test the friction and wear of a viscoelastic body which is represented by tire tread rubber under severe conditions by providing a driven disk, a driving disk, a balance spring which couples those disks, and a load adjusting means which adjusts a load placed on a test-piece, etc. CONSTITUTION:This device is equipped with the driving disk 7 which is fixed on the shaft 6 of a variable speed motor 5, the driven disk 8 which is fitted with the test-piece 17 coaxially with the shaft 6, the balance spring 10 which couples those two disks 7 and 8 with each other, and a displacement gauge 11 which measures the quantity of displacement of the driven disk 8. Further, the device is equipped with the variable speed motor 5 which rotates the test- piece 17 at an optional speed, the load adjusting means 4 which adjusts the load placed on the test-piece 17, a distance meter 29 which measures the travel distance of the test-piece 17, and a heating and cooling means 30 which varies the ambient temperature optionally in the test. Consequently, the friction and wear of the viscoelastic body represented by the tire tread rubber can be tested under severe conditions where the test can be conducted by neither a conventional friction nor wear testing machine.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a friction/wear testing device. For more details,
Speed, load, temperature, time, etc. can be set arbitrarily, and friction and wear tests on viscoelastic materials such as tire tread rubber can be performed under harsh conditions that cannot be tested with conventional friction testers and wear testers. The present invention relates to a friction/wear testing device.

[Conventional technology]

Conventionally, as a friction tester, for example, a road surface friction coefficient measuring device (Japanese Patent Publication No. 53-3475
(See Publication No. 2). In addition, as an abrasion tester, for example, a disc-shaped grindstone and a disc-shaped test piece are pressed against each other while rotating independently, and the test is performed due to the difference in surface speed between the grindstone and the test piece. There is a viscoelastic wear test device called the Lambourn type which measures the amount of wear on a piece (see Japanese Utility Model Publication No. 17702/1982).

However, all of these test machines perform friction tests and wear tests at low speeds and low loads.

Incidentally, since the wear of tire tread rubber is greatly affected by driving conditions, accurate evaluation cannot be made only by testing under certain test conditions, that is, testing under low speed and low load.

In particular, when the Lambourn type abrasion tester rotates the test piece at high speed, the disk-shaped test piece causes a so-called waving phenomenon. There was a problem that uneven wear occurred and accurate measurement values could not be obtained.

[Problem to be solved by the invention]

The present invention was made in view of such conventional problems, and is capable of performing friction tests on viscoelastic bodies such as tire trend rubber under severe conditions that could not be tested using conventional friction testers and wear testers. The object of the present invention is to provide a friction/wear testing device that can perform wear testing.

[Means to solve the problem]

That is, the friction/wear test device of the present invention includes a driven disk to which a test piece is attached, a drive disk whose axis is the same as that of the driven disk, a balance spring that connects these two disks, and the aforementioned a variable speed motor having a displacement meter for measuring the amount of displacement of the driven disk and rotating the test piece at an arbitrary speed; a load adjusting means for adjusting the load applied to the test piece; It consists of a distance meter that measures the distance traveled by the test piece, and heating/cooling means that can arbitrarily change the ambient temperature during the test.

Here, the load adjustment means for adjusting the load applied to the test piece is a coil spring bridged between the underframe and the variable speed motor that rotates the test piece, and a threaded rod that can adjust the spring force of this coil spring. It is desirable to form.

However, the load applied to the test piece may be adjusted using a weight.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a friction/wear testing device, in which a variable speed motor 5 with an electromagnetic brake is installed in a holder 3 fixed on an underframe 2 via a load adjusting means 4.

The underframe 2 and the holder 3 are sealed except for the lower part of the underframe 2, so that the inside of the underframe 2 can be heated or cooled to a predetermined temperature.

Further, a drive disk 7 is fixed to the shaft 6 of the variable speed motor 5. Further, a shaft 9 of a driven disk 8 having the same axis as the shaft 6 is rotatably attached to the shaft 6 of the variable speed motor. The driving disk 7 and the driven disk 8 are connected by a balance spring 10. When the driving disk 7 rotates at a predetermined speed, the driven disk 8 is driven in a state where the balance spring 10 is balanced. The amount of displacement of the balance spring 10 is measured by a displacement meter 11 attached to the lower surface of the drive disk 7. The amount of displacement of the balance spring 10 measured by the displacement meter 11 is input as a coefficient of friction to the computer 13 via the slip ring 12 attached to the top surface of the drive disk 7, and is also displayed on the display 14. ing. Further, it can be printed out by a printer 15 if desired. The rotational speed of the variable speed motor 5 is determined by the computer 13.
It is now controlled by. Further, the rotational speed is inputted to the computer 13 through an input device 16.

A plurality of test pieces 17 are attached to the lower surface of the driven disk 8 described above via supports 18.

These test pieces 17 are arranged in the same circle A as shown in FIG.
placed above. Further, as shown in FIG. 1, rollers 19 are attached to the lower surface of the driving disk 8 for applying a vertical load to the test piece 17 of the driven disk 8.

As shown in FIG. 3, the load adjusting means 4 described above is formed from a coil spring 21 and a threaded rod 20 screwed onto a bracket 22 of the holder 3. This coil spring 21
is supported by a tray 23 fixed to the lower end of the threaded rod 20 and a tray 25 attached to the bracket 24 of the variable speed motor 5. Since the head of the threaded rod 20 protrudes from the hole 26 of the holder 3, the spring force of the coil spring 21 is adjusted by turning the threaded rod 20 clockwise or counterclockwise using a jig such as a screwdriver, thereby removing the test piece 1.
The load applied to 7 can be adjusted as desired.

A gasket (not shown) is attached to the hole 26 of the holder to keep the holder 3 airtight.

Further, the distance meter 27 that measures the traveling distance of the test piece 17 is
The projection 28 attached to the upper surface of the drive disk 7 and the projection 2
A counter 29 attached to the underframe 2 so as to face 8
is formed by. The running distance of the test piece 17 can be measured by processing the number of revolutions of the driving disk 7 measured by the counter 29 by the computer 13.

Furthermore, an electric heater 31 and a cooling coil 32 as heating/cooling means 30 are attached to the underframe 2. The computer 13 controls the electric power supplied to the electric heater 31 or the refrigerant supplied to the cooling coil 32 to maintain the inside of the underframe 2 at a predetermined temperature. 33 is a temperature detector, and the temperature inside the underframe 2 is fed back to the computer 13.

Next, the measurement operation of the friction/wear test device described above will be explained.

The test pieces 17 are attached to the supports 18 of the driven disc 8 in advance, and the test pieces 17 are adjusted by the load adjusting means 4.
Adjust the load applied to the Further, the rotation speed of the variable speed motor 5 and the travel distance of the test piece 17 are input into the computer 13 using the input device 16 . Further, when heating the inside of the underframe 2 to a predetermined temperature, the connector of the heater 31 is inserted into an outlet, and the set temperature is input into the computer 13.

Next, the friction/wear test device 1 is placed on a surface to be measured, for example, a road surface R.
Place it on top. In this state, turn on the power switch (not shown). This causes current to flow through the variable speed motor 5, causing the drive disk 7 to rotate at a predetermined speed. Further, the driven disk 8 also rotates via the balance spring 10. At this time,
Frictional force acts on the test piece 17 in contact with the road surface R, causing twisting between the driving disc 7 and the driven disc 8.

This force displaces the balance spring 10, and the amount of displacement is measured by a displacement meter 11. The value is inputted into the computer 13 as a friction coefficient and displayed on the display 14.

On the other hand, the number of rotations of the drive disk 7 is counted by a counter 29, and when the test piece 17 has traveled a predetermined distance, the power switch is turned off and the variable speed motor 5 is suddenly stopped. Then, the amount of wear of the test piece is measured from the difference in weight between the test piece 17 before and after the test.

In the above explanation, we have explained the case where the test pieces are arranged on one circle, but as shown in Figure 4, by placing the test pieces on two circles A and B respectively, the degree of severity can be varied. This makes it possible to perform multiple tests at the same time.

FIG. 5 is a diagram showing the relationship between the amount of wear of the test compound and the degree of severity, and it can be seen that as the degree of severity increases, the order of the amount of wear of the test compound changes. Therefore, the test compound can be accurately evaluated based on FIG.

The composition of the test compound is as follows.

■5025: SBR carbon 95 phr ■508
3: SBR carbon 93phr oil 3phr■50
49: NR type carbon 45phr oil 2phr■
5138: NR/BR carbon 75phr oil 6p
hr [Effects of the Invention] As described above, the present invention provides a driven disk to which a test piece is attached, a drive disk having the same axis as the driven disk, and a balance spring that connects these two disks. and a displacement meter for measuring the amount of displacement of the driven disk, a variable speed motor for rotating the test piece at an arbitrary speed, and a load adjustment means for adjusting the load applied to the test piece. , a distance meter for measuring the traveling distance of the test piece, and a heating/cooling means that can arbitrarily change the ambient temperature during the test.
It is now possible to perform friction and abrasion tests on viscoelastic bodies, such as tire tread rubber, under harsh conditions that could not be tested with conventional friction and abrasion testers, allowing for accurate evaluations that match the usage conditions. Now you can lower the .

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view of the friction/wear test device according to the present invention, Fig. 2 is an explanatory diagram showing the arrangement of test pieces, and Fig. 3 is an enlarged view of the main parts of the friction/wear test device according to the present invention. , FIG. 4 is an explanatory diagram showing another arrangement of test pieces, and FIG. 5 is a diagram showing the relationship between the amount of wear of the test compound and the degree of severity. 4...Load adjustment means, 5...Variable speed motor, 7...
- Drive disk, 8... Driven disk, lO... Balance spring, 11... Displacement meter, 17... Test piece, 29...
Distance meter, 30...Heating/cooling means, Fig.

Claims (1)

[Claims] A driven disk to which a test piece is attached, a driving disk whose axis is the same as that of the driven disk, a balance spring that connects these two disks, and a displacement meter that measures the amount of displacement of the driven disk. and a variable speed motor that rotates the test piece at an arbitrary speed, a load adjustment means that adjusts the load applied to the test piece, and a distance meter that measures the distance traveled by the test piece. A friction/wear testing device consisting of heating and cooling means that can arbitrarily change the ambient temperature during testing.