JPH0820352B2 - Load-controlled friction wear tester - Google Patents

Description

TECHNICAL FIELD The present invention relates to a friction and wear tester that performs a friction and wear test by bringing two or more objects into contact with each other.

(Prior Art) Conventionally, in a friction wear tester for observing a friction wear phenomenon by pressing another test piece against one test piece that rotates or reciprocates linearly, for example, as shown in FIG. As described above, the weight 3 is added to the arm 2 to which the rod-shaped test piece 1 is attached, and the gravity is used to press the rod-shaped test piece 1 against the rotating cylindrical test piece 4 to set a predetermined load, or Alternatively, as shown in FIG. 12 (b), the load is set by utilizing the pulling force or the pushing force of the spring 5.

(Problems to be Solved by the Invention) However, in the friction and wear tester using the load device using the weight and the spring described above, the friction and wear test can be performed in a state where the load is constant. It was impossible to carry out a friction and wear test while changing the load.

In an actual machine, when two or more substances repeat frictional action, resulting in minute chips, rustles, etc., and when the phenomenon of wear is a problem, wear occurs under the condition that the load is constant. In many cases, the load acting on the friction surface fluctuates during the friction process. In addition, in a portion where the load changes abruptly, wear may significantly progress, which may cause a serious problem.

In order to perform the friction and wear test under conditions as close as possible to the friction and wear conditions in an actual machine, a friction and wear tester that performs the friction and wear test while varying the load is necessary.

An object of the present invention is to provide a load control type friction wear tester capable of accurately and repeatedly reproducing the friction wear phenomenon accompanied by load fluctuation as described above.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the present invention provides a friction wear test machine that causes a friction wear phenomenon in a state where a rod-shaped test piece is pressed against a movable test member. An arm movable in the direction of a different test member, an elastic body on which a load detecting pickup fixed to the lower part of the arm is mounted, and a rod-shaped test piece attached to the lower end of the elastic body,
A movable test member to which the rod-shaped test piece is pressed, a load generator for pressing the rod-shaped test piece against the movable test member, a load control device connected to the load generator, and the load detection device. A load detection device connected to the pickup, a load detection pattern generation device, compares the output signal from the load detection pattern generation device with the output signal from the load detection device, and sends an output signal to the load control device. A compensator is provided, and the test load is changed by operating the load generator according to the motion state of the movable test member.

(Operation) According to the present invention, since it is configured as described above, the friction and wear test is performed while accurately changing the load acting on the friction surface according to the rotation angle or position of the test piece that makes a rotary motion or a linear reciprocating motion. It can be carried out.

(Example) Hereinafter, the Example of this invention is described in detail, referring drawings.

FIG. 1 is a block diagram of a load control type friction and wear tester showing a first embodiment of the present invention, FIG. 2 is a perspective view of the friction and wear tester of FIG. 1, and FIG. It is a perspective view of the load detection pickup part.

In these figures, the rod-shaped test piece 6 is pressed against the side surface of the rotating cylindrical test piece 7 by the attraction force of the electromagnet. The cylindrical test piece 7 is driven by a motor or the like, and rotates about its central axis. Cylindrical test piece 7
A rotation angle detector (for example, a rotary encoder) 8 that detects a rotation angle of a frictional portion on the side surface of the cylindrical test piece 7 is attached to the rotation shaft of. The output of the rotation angle detector 8 is connected to the load pattern generator 9. The load pattern generator 9 has a ring counter 9a, a ROM 9b, and a D / A converter 9c, and the ROM 9b stores the load value corresponding to the rotation angle.

On the other hand, the rod-shaped test piece 6 is fixed via an elastic body (for example, an octagonal elastic ring) 10 to an arm 12 whose one end is rotatably supported by a bearing 11. The other end of arm 12
13a and 13b are made of a ferromagnetic material, and the attraction force of the electromagnet acts on this portion. A load detecting pickup (for example, a strain gauge) 14 is attached to the elastic body 10, and the load detecting pickup 14 is connected to a load detecting device (for example, a force sensor) 15. The outputs of the load pattern generator 9 and the load detector 15 are connected to the compensator 16. The output of the compensator 16 is the excitation circuit 17a for the electromagnet,
It is connected to 17b (load control device). The electromagnet exciting circuits 17a and 17b include electromagnet coils 18a and 18b, respectively.
Is connected. These electromagnets act on the other ends 13a and 13b of the arm 12 made of a ferromagnetic material. In addition,
In this friction and wear tester, as shown by the dotted line, the motion of the arm 12 is detected by the eddy current displacement sensor, the gap between the electromagnet and the arm 12 is set, and the arm 12 jumps up due to the unevenness of the contact surface. In order to prevent this, it can be used when performing control to add appropriate spring properties and damping characteristics.

The friction and wear test system will be analyzed and described in detail below.

 FIG. 4 is a diagram showing a physical model of this device.

According to this, the equation of motion of the arm is as follows.

_{J + D = -mgl g + k} (δ 0 -l k θ + y) l k + (F 1 -F 2) l e ... (1) where, J: inertia of the arm moment m: mass of the arm D: bearing portion of the viscous Resistance coefficient θ: Rotation angle of arm y: Displacement of contact surface δ ₀ : Initial strain of octagonal elastic ring k: Spring constant of octagonal elastic ring F _n : Electromagnetic attraction force (n = 1, 2) Formula (1) above In, when the attraction force of each electromagnet is linearly approximated and the equilibrium condition is considered, the following equation is obtained.

J + D + ^{_{[kl k 2 - (G 1 +}} G 2) l e 2 ] _{θ = (H 1 i 1 -H} 2 i 2) l e + kyl k ... (2) where, H _n, G _n: the characteristics of the electromagnet Determining constant i _n : Variation of exciting current of electromagnet (n = 1, 2) Further, an equation relating to variation f of load [k = (y−l _k θ)] is obtained by the following equation.

_{+ A 1 + a 0 f =} b 0 u + w ... (3) _{where, a 1 = D / J a} 0 = ^{_{[kl k 2 - (G 1 +}} G 2) l e 2 ] _{/ J b 0 = k (H} 1 + H ₂ ) l _k l _e / J u = (H ₁ i ₁ −H ₂ i ₂ ) / (H ₁ + H ₂ ) w = k + k (D / J) −k (G ₁ + G ₂ ) (l _k ² / J ) Y Next, the control system will be described.

The purpose of control is to match the actual load to the required load pattern as accurately as possible. As will be described later, the load pattern may change in a step shape, a sine wave shape, or a triangular wave shape, and the conditions required for the control system also change depending on the shape of the pattern, but in general, ( i) The steady-state deviation becomes zero. (ii) Within the range allowed by the physical and technical constraints of the device, it is required that the response be as fast as possible while having appropriate damping characteristics.

Further, as can be seen from the equation (3), the fluctuation of the position of the contact surface acts as a disturbance when the load is controlled. Possible causes for this are (a) eccentricity of the cylindrical test piece and (b) roughness of the contact surface.

In the case of (a), w is a sine wave signal having the same frequency as the rotation speed of the main shaft.

In the case of (b), the signal has a higher frequency component.

The control system shown in FIG. 5 includes an I-PD compensator and a periodic disturbance compensator using an observer.

 The dynamic characteristic of this control system is expressed by the following equation.

Therefore, in this control system, the coefficient q ₀ of the I-PD compensator,
By adjusting p ₀ and p ₁ , the above (i), (i
The condition of i) can be satisfied, and even if the cylindrical test piece is eccentric, the load can be set by the action of the periodic disturbance compensator without being affected by it.

Next, the operation of the load control type friction wear tester shown in FIGS. 1 and 2 will be described.

When the cylindrical test piece 7 rotates, the load pattern generator 9 outputs the stored target load value in accordance with the output of the rotation angle detector 8 attached to the rotary shaft.

In FIG. 10, reference numeral 45 is a rectangular wave, 46 is a sine wave, and 47 is an output of the load pattern generator when the load is changed into a triangular wave. Here, the vertical axis represents the target load value and the horizontal axis represents the rotation angle of the cylindrical test piece.

Since the size of the rotation angle increases by 360 ° each time the test piece makes one rotation, the portions of the cylindrical test piece 7 that are in friction with the rod-shaped test piece 6 are at the rotation angle α and the rotation angle α ± 360 °. It is the same as when. The compensator 16 compares the load target value output from the load pattern generation device 9 with the actual load value output from the load detection device 15 to generate a control signal such that they match, It outputs to the electromagnet excitation circuits 17a and 17b as a control device. Excitation circuit for electromagnet 17a, 1
7b changes the current flowing through the coils 18a, 18b of the electromagnet according to the control signal. As a result, the frictional load value between the rod-shaped test piece 6 and the cylindrical test piece 7 is controlled so as to match the target load value.

In FIG. 11, reference numerals 48, 49, and 50 respectively represent actual load values when the target load pattern values are rectangular wave 45, sine wave 46, and triangular wave 47 as shown in FIG. Here, the vertical axis represents the actual load value and the horizontal axis represents the rotation angle of the cylindrical test piece. From FIG. 11, it can be seen that the load pattern that is in good agreement with the target load pattern is realized with good repeatability. The load pattern waveform can be freely set according to the purpose of the friction and wear test by rewriting the stored contents of the load pattern generator.

With the above configuration, the friction and wear test can be performed while the load value acting on the friction surface is repeatedly and accurately varied according to the rotation angle of the cylindrical test piece.

FIG. 6 is a configuration diagram of a load control type friction and wear tester showing a second embodiment of the present invention, and FIG. 7 is a perspective view of the load control type friction and wear tester of FIG.

In these figures, the rod-shaped test piece 19 is pressed against the surface of the rotating disc-shaped test piece 20 by the attraction force of the electromagnet. The disk-shaped test piece 20 is driven by a motor or the like and rotates about its central axis. Disc-shaped test piece 20
A rotation angle detector (for example, a rotary encoder) 21 that detects a rotation angle of a friction portion on the surface of the disc-shaped test piece 20 is attached to the rotation shaft of. The output of the rotation angle detector 21 is connected to the load pattern generator 22. A load value corresponding to the rotation angle is stored in the load pattern generator 22.

On the other hand, the rod-shaped test piece 19 is fixed to an arm 25 rotatably supported by a bearing 24 at one end via an elastic body (for example, an octagonal elastic ring) 23. The other end 26 of the arm 25 is made of a ferromagnetic material, and the attraction force of the electromagnet acts on this part. A load detecting pickup (for example, a strain gauge) 27 is attached to the elastic body 23, and the load detecting pickup 27 is connected to a load detecting device (for example, a force sensor) 28.

The outputs of the load pattern generator 22 and the load detector 28 are connected to the compensator 29. The output of the compensator 29 is connected to the electromagnet excitation circuit 30 (load control device). An electromagnet coil 31 is connected to the electromagnet excitation circuit 30. This electromagnet is an arm made of the above-mentioned ferromagnetic material.
It acts on the other end 26 of 25.

Next, the operation of this load control type friction wear tester will be described.

When the disc-shaped test piece 20 rotates, the load pattern generator responds to the output of the rotation angle detector 21 attached to the rotating shaft.
22 outputs the stored load target value. The compensator 29 is
Load target value output from the load pattern generator 22,
The actual load value output from the load detection device 28 is compared, and a control signal that matches them is generated and output to the electromagnet excitation circuit 30 as the load control device.

The electromagnet exciting circuit 30 changes the current flowing through the coil 31 of the electromagnet in accordance with the control signal. As a result, the friction load value between the rod-shaped test piece 19 and the disc-shaped test piece 20 is controlled so as to match the load target value. With the above configuration, the friction and wear test can be performed while the load value acting on the friction surface is repeatedly and accurately changed according to the rotation angle of the disc-shaped test piece 20.

FIG. 8 is a block diagram of a load control type friction and wear testing machine showing a third embodiment of the present invention, and FIG. 9 is a perspective view of the friction and wear testing machine of FIG.

In these figures, the rod-shaped test piece 32 is pressed against the surface of the flat plate-shaped test piece 33 that reciprocates linearly by the attraction force of the electromagnet. The flat plate test piece 33 is driven by a linear motor (not shown) or the like, and linearly reciprocates in the driving direction. The flat plate test piece 33 has a position detector (for example, a position detector that detects the position of the friction portion on the surface of the flat plate test piece 33.
Linear encoder) 34 is attached. The output of the position detector 34 is connected to the load pattern generator 35. The load pattern generator 35 stores a load value corresponding to the position of the frictional portion of the disc-shaped test piece 33 in the reciprocating direction.

On the other hand, the rod-shaped test piece 32 is fixed via an elastic body 36 to an arm 38 whose one end is rotatably supported by a bearing 37. The other end 39 of the arm 38 is made of a ferromagnetic material,
The attraction force of the electromagnet acts on this part. A load detecting pickup 40 is attached to the elastic body 36, and the pickup 40 is connected to a load detecting device 41. The outputs of the load pattern generator 35 and the load detector 41 are connected to the compensator 42. The output of the compensator 42 is the excitation circuit for the electromagnet.
It is connected to 43 (load control device). An electromagnet coil 44 is connected to the electromagnet excitation circuit 43. This electromagnet is the other end of the arm 38 made of the above-mentioned ferromagnetic material.
Acts on 39.

Next, the operation of this load control type friction wear tester will be described.

When the flat plate-shaped test piece 33 moves linearly back and forth, the flat plate-shaped test piece
The load pattern generator 35 outputs the stored target load value in accordance with the output of the position detector 34 attached to the unit 33. The compensator 42 compares the load target value output from the load pattern generation device 35 with the actual load value output from the load detection device 41 to generate a control signal such that they match, It outputs to the electromagnet excitation circuit 43 as a control device.

The electromagnet exciting circuit 43 changes the current flowing through the coil 44 of the electromagnet according to the control signal. As a result, the frictional load value between the rod-shaped test piece 32 and the flat plate-shaped test piece 33 is controlled so as to match the load target value. With the above-described configuration, the friction and wear test can be performed while the load value acting on the friction surface is repeatedly and accurately changed according to the position of the flat plate-shaped test piece 33.

The present invention is not limited to the above-mentioned embodiment, and various modifications can be made based on the spirit of the present invention.
They are not excluded from the scope of the present invention.

(Effect of the Invention) As described above, according to the present invention, the load acting on the friction surface is adapted to the target value by the compensator according to the rotation angle or the position of the test piece that makes a rotary motion or a linear reciprocating motion, The friction and wear test can be performed while changing the accuracy.

[Brief description of drawings]

FIG. 1 is a block diagram of a load control type friction and wear tester showing a first embodiment of the present invention, FIG. 2 is a perspective view of the load control type friction and wear tester of FIG. 1, and FIG. 3 is its load control. Perspective view of a load detecting pickup portion of the frictional wear testing machine, FIG. 4 is a view showing a physical model of the load-controlled frictional wear testing machine, FIG.
FIG. 6 is a block diagram of a load control system of the present invention, FIG. 6 is a configuration diagram of a load control type friction wear test machine showing a second embodiment of the present invention, and FIG. 7 is a load control type friction wear test of FIG. 8 is a perspective view of the load control type friction and wear tester showing the third embodiment of the present invention, FIG. 9 is a perspective view of the load control type friction and wear tester of FIG. FIG. 11 is a diagram showing an example of a target pattern of load, FIG. 11 is a diagram showing an actual load value, and FIG. 12 is a diagram showing a loading method in a conventional friction and wear tester. 6,19,32 …… Rod-shaped test piece, 7 …… Cylindrical test piece, 8,21…
… Rotation angle detector (rotary encoder), 9,22,35 ……
Load pattern generator, 9a …… Ring counter, 9b ……
ROM, 9c …… D / A converter, 10,23,36 …… Elastic body (octagonal elastic ring), 11,24,37 …… Bearing, 12,25,38 ……
Arms, 13a, 13b, 26, 39 …… Other end of arm (ferromagnetic material), 14,27,40 …… Pickup for load detection (strain gauge), 15,28,41 …… Load detection device (force Sensor),
16,29,42 …… Compensator, 17a, 17b, 30,43 …… Electromagnetic excitation circuit (load control device), 18a, 18b, 31,44 …… Electromagnetic coil, 20 …… Disc-shaped test piece , 33 …… Flat plate test piece, 34…
… Position detector (linear encoder), 45 …… rectangular wave output, 46 …… sine wave output, 47 …… triangular wave output,
48 …… actual rectangular wave load value, 49 …… actual sine wave load value, 50 …… actual triangular wave load value.

Claims (4)

[Claims] 1. A friction and wear tester for causing a friction and wear phenomenon while a rod-shaped test piece is pressed against a movable test member, comprising: (a) an arm movable in the direction of the movable test member; ) An elastic body on which a load detecting pickup fixed to the lower part of the arm is mounted, (c) a rod-shaped test piece attached to the lower end of the elastic body, and (d) a movable body where the rod-shaped test piece is pressed. A test member, (e) a load generating device for pressing the rod-shaped test piece against a movable test member, (f) a load control device connected to the load generating device, (g) the load detecting pickup A load detection device connected to the load detection device, (h) a load detection pattern generation device, and (i) an output signal from the load detection pattern generation device and an output signal from the load detection device are compared to control the load. And a compensator for sending an output signal to the device, and (j) a load control type friction, wherein the load generating device is actuated to change the test load according to the motion state of the movable test member. Abrasion tester. 2. The load-controlled friction and wear tester according to claim 1, wherein the movable test member is a rotating cylindrical test piece. 3. The load-controlled friction and wear tester according to claim 1, wherein the movable test member is a rotating disc-shaped test piece. 4. The load-controlled friction and wear tester according to claim 1, wherein the movable test member is a flat plate-shaped test piece that performs linear motion.