JPH06221990A - Friction tester - Google Patents

Abstract

PURPOSE:To provide a friction tester, which can readily simulate and perform the friction test by using the test pieces of many kinds of products without manufacturing the prototype of product that is actually used for every piece when the friction test of viscoelastic material is performed. CONSTITUTION:A sample holder 15, to the tip of which a sample W is removably attached, is provided in a rotary drum 3. The tip part of a movable holder supporting arm 14 is inserted into the axial direction and the direction of the diameter of the rotary drum. The sample holder 15 is attached to the tip of a spline shaft 24, which is arranged so that the shaft 24 can be slid and rotated in the direction perpendicular to the holder supporting arm 14. The holder 15 holds the sample W so that the sample can be attached and removed. An energyzing means 42, which compresses the sample W attached to the sample holder 15 to the inner wall side of the rotary drum 3, and a releasing means 43, which releases the sample W from the inner wall side of the rotary drum 3, are provided at the spline shaft 24.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a friction test apparatus for viscoelastic materials such as rubber, and more specifically, it does not use various kinds of trial tires to produce friction by using sample pieces as tire constituent materials. The present invention relates to a friction test device capable of obtaining the same effect as when a friction test of a prototype tire is performed by performing a test.

[0002]

2. Description of the Related Art Conventionally, a friction test apparatus for a viscoelastic material such as a tire is a slide resistance type friction test apparatus or a Japanese Patent Publication No. As disclosed in No. -10062, a pin-on-desk type friction test device is mainstream, and as disclosed in Japanese Patent Publication No. 3-63012, a friction test device on a road is proposed as a rotary type. Has been done.

Further, as a recent friction test device, a device for conducting a friction test by bringing a sample into contact with the inner wall surface of a cylindrical rotating drum has been proposed (Kautsch und Gummi Vol 2
2, P373, (1969)).

[0004]

However, all of the conventional friction testers as described above are mainly based on the slip resistance which is measured while sliding the sample on the friction surface. When conducting the test, the friction data of the friction test based on the sliding resistance had to be used despite the rolling resistance, which was different from the actual use condition.

[0005] In addition, a tire testing apparatus for snow and ice roads in a room is used for evaluation road tests of studless tires and all-season tires, tests on test courses, and the like. An ice layer of a specified thickness is formed on the inner wall surface of the rotating drum installed in the tank, and the prototype of the snow and ice road tire to be actually used is attached to the inside surface of this rotating drum to rotate the rotating drum. However, it is a device that is designed to perform a friction test on a prototype (The Society of Automotive Engineers of Japan, N038, P71, (198
8)).

[0006] In general, when a tire friction test is performed, the evaluation of the tire constituent material itself is important as a screening test before the tire trial production. It is done using tires,
Therefore, not only the evaluation of the tire constituent material itself but also the evaluation as a selection test of the constituent material is an expensive test, and in the case of the conventional device as described above, the slip resistance is mainly used as described above. Therefore, it is not a rotary type that simulates the running of actual vehicle tires, but it requires a lot of time and effort as well as a large number of tire prototypes must be manufactured, and it also costs a lot of money was there.

The present invention was devised by focusing on the above-mentioned conventional problems, and when a friction test of a viscoelastic material is performed,
It is possible to simulate friction tests easily by using sample pieces of various kinds of products without making one trial product of the product actually used, and it is possible to greatly reduce the time and effort required for product trial production. It is an object of the present invention to provide a friction test device that can achieve cost reduction as well as cost reduction.

[0008]

In order to achieve the above-mentioned object, the present invention rotatably houses a hollow cylindrical rotary drum formed of a transparent material inside a constant temperature bath via a drive unit, A sample holder to which a disk-shaped sample is detachably attached at the tip is provided in the rotary drum, and a biasing means for pressing the sample attached to the sample holder to the inner wall surface side of the rotary drum and a sample rotation It is a gist to provide a releasing means for separating from the inner wall surface side of the drum, and to provide the sample holder with a rotation driving device for rotating the sample while being in contact with the inner wall surface of the rotating drum. Also,
It is also possible to connect the sample holder to adjusting means for adjusting the contact inclination angle and the slip angle of the sample with respect to the inner wall surface of the rotating drum.

[0009]

The present invention is constructed as described above, and the sample piece of the material to be the product tire is set in the apparatus, and the rotary drum and the sample are rotated while the sample is pressure-bonded to the inner wall surface of the rotary drum. Then, by further adjusting the contact inclination angle of the sample, the friction test should be performed under exactly the same conditions as when performing the friction test of the product due to changes in the slip ratio, slip angle, and camber angle of the sample piece. In addition to greatly reducing the time and effort required for product trial production, it is also possible to reduce costs.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a perspective view of a main part of a friction test device showing a first embodiment of the present invention, FIG. 2 is a plan view of the friction test device, and FIG. 3 is an enlarged sectional view taken along the line AA of FIG. In the friction test device, a hollow cylindrical rotary drum 3 is rotatably mounted inside a substantially constant temperature chamber 1 whose temperature can be adjusted (−20 ° C. to 40 ° C.) via a plurality of bearings 2.

The cylindrical rotary drum 3 is formed of a transparent material such as glass, and has an ice layer or water layer of uniform thickness with a constant thickness (about 10 mm) formed on its inner surface. A pulley 4 for rotation transmission is attached to the outer peripheral surface on one end side thereof, and the pulley 4 for rotation transmission and a rotation driving motor installed outside the constant temperature bath 1. A timing belt 7 is wound around the timing pulley 6 attached to the rotary shaft of the driving device 5 such as the above, and the rotational driving force of the driving device 5 is transmitted to the rotary drum 3.

On one side of the constant temperature bath 1, there is provided an opening / closing door 9 provided with a double-structured glass window portion 8 through which the internal rotating drum 3 can be seen, and inside the glass window portion 8. Contains a plurality of optical fibers 10 for projecting light onto the rotary drum 3. Further, an image reading device 11 such as a television camera capable of observing the inside through the glass window portion 8 is installed outside the opening / closing door 9, and the outside thereof is covered with a cover 12. This image reading device 11 is connected to an image analysis device 61 of the control device 60 of FIG. 6 described later, and analyzes the ground contact state between the sample W and the inner wall surface of the rotating drum 3 in the slip state or the camber state of the sample W. Is configured.

The inside of the rotary drum 3 is shown in FIGS.
As shown in FIG. 3, a holder support arm 14 that is movable in the axial direction (X direction) and the radial direction (Y direction) of the rotary drum 3 is inserted through the opening 13 formed on the side surface of the constant temperature bath 1. At the tip of the support arm 14,
A sample holder 15 to which the sample W is detachably attached is provided at the tip.

The rear end side of the holder support arm 14 is located outside the constant temperature bath 1 in the radial direction of the rotary drum 3 (Y
Direction) is mounted slidably on two parallel guide rails 16 laid in the direction) via a base plate 17, and the base plate 17 is mounted on a feed screw rod 18 disposed between the two guide rails 16. When the feed screw rod 18 is screwed through the nut 19 and is rotated by the drive motor 20 for sample exchange provided at one end of the feed screw rod 18, the base plate 17 causes the two guide rails 1 through the nut 19 to rotate.
6 is configured to move in the radial direction (Y direction) of the rotary drum 3.

The two parallel guide rails 16 laid in the radial direction (Y direction) of the rotary drum 3 are provided outside the constant temperature bath 1 in the axial direction (X direction) of the rotary drum 3. It is placed on a guide rail 21 of a book via a support plate 22, and the support plate 22 is screwed to a traveling feed screw rod 23 arranged between the two guide rails 21 via a nut (not shown). It is fitted. The traveling drive motor 2 provided at one end of the traveling feed screw rod 23
When the traveling feed screw rod 23 is rotated by 3a, the support plate 22 and the two guide rails 1 laid thereon are provided.
6. The holder support arm 14 and the sample holder 15 installed on the base plate 17 placed on the guide rail 16 move along the axial direction (X direction) of the rotary drum 3.

Next, as shown in FIGS. 4 and 5, the sample holder 15 provided at the tip of the holder supporting arm 14 can slide and rotate in a direction orthogonal to the holder supporting arm 14 by penetrating the holder supporting arm 14. Attached to the tip of the spline shaft 24 disposed in the
Is spline-fitted to the outer cylinder 26 supported by the support plate 25, and the outer cylinder 26 is rotatably supported by the bearing member 27. A ball spline shaft may be used as the spline shaft 24.

The outer cylinder 26 is integrally provided with a worm wheel 28 for adjusting a slip angle. The worm wheel 28 is connected to a drive motor 29 for adjusting a slip angle as shown in FIG. 30 meshes. In the sample holder 15 attached to the tip of the spline shaft 24, a sample holding frame 32 having a U-shaped cross section for attaching the sample W is attached via a shaft 33 in a support frame 31 having a U-shaped cross section. At the center of the frame 32, the sample W can be clamped and held by a holding shaft 34 and a nut 35.

A worm wheel 36 for adjusting the camber angle is attached to the upper end of the shaft 33 for supporting the sample holding frame 32 in the support frame 31, mainly as shown in FIGS. 1, 3 and 4. This worm wheel 36 has
A worm gear 38 connected to the drive motor 37 for adjusting the camber angle is meshed. Further, as shown in FIGS. 2 and 3, the holding shaft 34 that holds and holds the sample W, as shown in FIGS.
For example, a drive motor 40 for rotating a sample is provided through joint members 39 and 39a formed of universal joints such as a spline shaft, a ball spline shaft, and a flexible shaft.
And a torque meter 4 for detecting the frictional force required to rotate the sample as a torque value in the middle of the joint member 39.
1 is attached.

On the other hand, on the rear end side of the spline shaft 24, the urging means 42 for pressing the sample W attached to the sample holder 15 to the inner wall surface 3a side of the rotating drum 3 is provided.
And a releasing means 43 for separating the sample W from the side of the inner wall surface 3a of the rotary drum 3, and the urging means 42 are the same as those shown in FIG.
~ As shown in FIGS. 3 and 5, the spline shaft 24
One end of the load arm 44 is fixed to the rear end side, and the wire 47 connected to the load weight 46 via the metal fitting 45 is connected to the other end side. The wire 47 is engaged with and supported by pulleys 48a and 48b for wire guides provided upright on the front end side and the rear end side of the holder support arm 14, and is attached to the front end of the wire 47 suspended from the pulley 48b. Is detachably attached with the above-mentioned load weight 46 for pressing the sample W onto the inner wall surface 3a of the rotary drum 3.
Further, a cylinder 49 for releasing the load is provided below the load weight 46.

The sample W is placed on the inner wall surface 3a of the rotary drum 3.
As shown in FIGS. 1 and 4, one end of the wire 51 is connected and fixed to the center of the nut 50 for fixing the load arm 44 to the rear end side of the spline shaft 24. The wire 51 is wound around a wire guide pulley 52 erected on the support plate 25, and a sample returning weight 53 is detachably attached to the tip thereof.

Next, the control circuit 60 of the friction test apparatus in the first embodiment will be described with reference to FIG. As shown in FIG. 6, the control circuit 60 of the friction test device includes a camber angle control circuit 63 for the sample W, a slip angle control circuit 64 for the sample W, and a slip ratio control circuit 65 connected to a central processing control device 62. In the camber angle control circuit 63 of the sample W, an image reading device 11 such as a bicamera installed on the side surface of the rotating drum 3 is connected to an image analysis device 61 connected to a central processing control device 62. There is.

For setting the camber angle α of the sample W, a signal programmed in the central processing control device 62 is output to the drive control device 66, and the drive motor 3 for adjusting the camber angle is output.
The sample W is set to a predetermined camber angle via 7, and the set camber angle is detected by the rotary encoder 68a and the pulse counter 68b and compared with the camber angle set in advance in the camber angle setter 69. Then, the camber angle is controlled to be constant.

For setting the speed of the sample W in the axial direction (X direction) of the rotary drum 3, a signal programmed in the central processing control device 62 is output to the servo amplifier 70, and the sample W and the sample are transferred via the servo motor 71. Holder support arm 14
Is moved at a constant speed, at which time the tacho generator 7
The rotation speed is detected in step 2 and compared with the rotation speed set in the speed setting device 73 in advance to set and control the rotation speed to a constant value.

In this way, with the camber angle α of the sample W set, the state in which the sample W is pressed against the inner wall surface of the rotating drum 3 rotating at a predetermined rotation speed is read from the outside of the rotating drum 3 by the image reading device 11. And the image analysis device 61 based on a command from the central processing control device 62.
The image analysis is performed in. Further, the slip angle α in the slip angle control circuit 64 of the sample W is
The setting of _x is performed by outputting a signal programmed in the central processing control device 62 to the drive control device 74, setting the sample W to a predetermined slip angle via the drive motor 75 for slip angle adjustment, and setting the same. The slip angle detected by the rotary encoder 76 and the pulse counter 77,
The slip angle set in the slip angle setting device 78 is compared with the slip angle set in advance to set and control the slip angle to a constant value.

Further, the slip ratio control circuit 65 determines the rotation speed of the rotary drum 3 and the rotation speed of the sample W on the basis of the signals programmed in the central processing unit 62, and the servo amplifiers 79 and 80 and the servo motor. The rotation speeds are controlled to be constant via 81 and 82, the respective rotation speeds are detected by the tachogenerators 83 and 84, respectively, and are compared with the rotation speeds preset in the speed setters 85 and 86 so as to be constant. The rotation speed is set and controlled.

As for the set speed of the rotary drum 3, the signal programmed in the central processing control unit 62 is output to the servo amplifier 79, and the rotary drum 3 is transmitted via the servo motor 81.
Is rotated at a constant rotation speed, the rotation speed is detected by the tachogenerator 83 at that time, and the rotation speed set in the speed setting device 85 is compared with the rotation speed so that the rotation speed is controlled to a constant rotation speed. .

At this time, the rotation speeds of the rotary drum 3 and the sample W are detected by the rotation sensors 87 and 88, and the detected values are output to the slip ratio meter 91 through the peripheral speed meters 89 and 90 to determine the slip ratio. It is something to measure. The frictional force of the sample W is detected by the torque sensor 92, and is output to the torque display 94 via the amplifier 93 for display.

The control circuit 60 of the friction test apparatus as described above
Thus, the sample W is pressure-bonded to the inner wall surface 3a of the rotary drum 3 in a state of being applied with a predetermined load, rotated and moved, and the contact angle (camber angle, slip angle) of the sample W is appropriately changed. The friction test of the sample W can be performed. By performing the friction test using the sample W that is a tire constituent material in this way, it becomes possible to perform the test under the same conditions as the actual friction test of the tire, and the running condition of the tire, for example, on ice. Alternatively, in water, an ice layer or a water layer having a constant thickness is formed on the inner surface of the rotating drum 3, and in a normal road test, the sample W is pressure-bonded to the inner wall surface of the rotating drum 3. It is possible to measure the friction coefficient of the sample W itself under the simulated condition.

The grounding condition of the sample W in such a friction test is picked up by the image reading device 11 as described above, and this image is read by the image analysis device 61 based on a command from the central processing control device 62. By analyzing the image, a highly accurate friction test can be performed. Further, in the above example, the sample W (test piece) has an outer diameter of about 6 mm.
A disk-shaped one with a thickness of 0 mm and a thickness of about 10 to 20 mm is used, and the rotary drum 3 is made of glass and has a diameter of about 700 mm and a length of 5
A sample having a thickness of 00 mm and a thickness of 10 mm is used, and is driven to rotate independently of the sample W, and the rotation speed is 0 to 10 respectively.
It is driven at 0 Km / H.

The slip ratio of the sample W is 0 to 100.
%, Slip angle ± 10 °, camber angle ± 25 °, load 1-6 kg on ice, 1-30 kg on water layer,
While moving in the rotating drum 3, the image reading device 11 captures an image of the ground contact state of the sample W, and the image analysis device 61
The friction test is performed by analyzing the image in. Next, FIGS. 7 to 9 show a second embodiment in the friction test of the present invention. In this embodiment, the load (energizing means) applied to the sample W is rotated as shown in FIGS. 7 and 8. The drum 3 is made to act perpendicularly to the inner wall surface 3a, and the load is adjusted manually.

That is, the sample holder 15 is provided perpendicularly to the inner wall surface 3a of the rotary drum 3, and the sample holder 15 is provided.
A detachable weight 46a is attached to the rear end side of the spline shaft 24a provided in, so that a load is always applied in the vertical direction. Further, in FIG. 7, a flexible shaft 39a is used as a joint member. Since the other configurations and operations are substantially the same as those of the first embodiment, the same reference numerals are given and the description thereof will be omitted.

As shown in FIG. 9, the control circuit 60 is also provided with a pressing load setting device 95 for manual operation, and based on a signal programmed in the central processing control device 62, this signal is output to the drive control device 96. The load applied to the sample W via the linear actuator 97 is controlled, the load is detected via the load cell 98 and the amplifier 99, and is compared with the load set in advance by the pressing load setting device 95 to be constant. It is also possible to control so that the load of (1) acts on the sample W.

In FIG. 9, the linear actuator 97
Although the case where the above is used has been described, when the load is manually adjusted, the pressing load setting device 95, the drive control device 96, the linear actuator 97, the load cell 98, and the amplifier 99 are omitted. Since the other configurations are similar to those of the first embodiment, the same reference numerals are given and the description thereof is omitted.

[0034]

As described above, according to the present invention, a hollow cylindrical rotary drum formed of a transparent material is rotatably mounted inside the constant temperature bath through the driving device as described above, and inside the rotary drum, A sample holder to which a disk-shaped sample is detachably attached is provided at the tip, and the sample attached to the sample holder is
An urging means for pressing the inner wall surface of the rotating drum and a releasing means for separating the sample from the inner wall surface of the rotating drum are provided, and the sample holder is rotated while the sample is in contact with the inner wall surface of the rotating drum. Since a rotation drive device is provided, it is easy to simulate friction tests using a variety of product specimens without making one prototype of the product actually used when performing a friction test on viscoelastic materials. In addition to greatly reducing the time and effort required for product trial production, it is also possible to reduce costs.

Further, since the constituent materials of the product are evaluated in advance, there is an effect that it is extremely effective as a screening test before the trial manufacture of the product.

[Brief description of drawings]

FIG. 1 is a perspective view of a main part of a friction test device showing a first embodiment of the present invention.

FIG. 2 is a plan view of the friction test device according to the first embodiment of the present invention.

FIG. 3 is an enlarged sectional view taken along the line AA of FIG.

FIG. 4 is a side view taken along the line BB of FIG.

5 is a partial cross-sectional view of the spline shaft portion of FIG.

FIG. 6 is an explanatory diagram of a control circuit of the friction test device according to the present invention.

FIG. 7 is a front view of a friction test device according to a second embodiment of the present invention.

8 is a side view taken along the line CC of FIG.

FIG. 9 is an explanatory diagram of a control circuit of the friction test device according to the second embodiment of the present invention.

[Explanation of symbols]

1 constant temperature bath 3 rotating drum 3a inner wall surface of rotating drum 5 driving device 11 image reading device 14 holder support arm 15 sample holder 24 spline shaft 40 rotation driving device 42 urging means 43 releasing means W sample

Claims (2)

[Claims] 1. A hollow cylindrical rotary drum formed of a transparent material is rotatably mounted inside a constant temperature bath via a driving device, and a disk-shaped sample is provided at the tip of the rotary drum. A sample holder that is removably attached is provided, and a biasing means for pressing the sample attached to the sample holder to the inner wall surface side of the rotating drum and a releasing means for separating the sample from the inner wall surface side of the rotating drum are provided. A friction test apparatus, wherein the sample holder is provided with a rotation drive device for rotating the sample while keeping the sample in contact with the inner wall surface of the rotary drum. 2. The friction test apparatus according to claim 1, wherein the sample holder is connected to adjusting means for adjusting a contact inclination angle and a slip angle of the sample with respect to the inner wall surface of the rotary drum.