CN103822837B - A kind of frictional testing machine - Google Patents

Abstract

The invention discloses a friction testing machine. In the friction testing machine, a disc-shaped fixed test piece or a fixed reference piece is installed on a fixed seat, a moving test piece or a moving reference piece is installed on a movable seat, and the friction tester is driven by a driving device. Drive the movable seat to move along a straight line or a curved track. During the friction and wear process, the fixed test piece or fixed reference piece is fixed, while the movable test piece or fixed reference piece can move on the fixed test piece or fixed reference piece, while the dynamic test piece The test piece or the moving reference piece itself does not perform rotary motion, that is, there is no rotating body during the friction and wear test, and the electric signal can be transmitted between the moving test piece or the moving reference piece and the fixed test piece or fixed reference The sensor is directly installed on the parts to achieve the purpose of measuring the corresponding physical quantity. The sensor can also use a contact sensor, thereby solving the problem of inaccurate measurement results of the friction and wear test in the prior art caused by the friction disc constantly rotating.

Description

A friction testing machine

technical field

The invention relates to the field of friction and wear testing, in particular to a friction testing machine.

Background technique

At present, most of the equipment used in friction and wear tests are ball-disc or pin-disk friction testing machines. Taking the pin-disc friction testing machine as an example, the traditional pin-disc friction testing The disk rotates, but the pin does not move. For example, in the description of Chinese patent document CN103308409A, a rotary disc type multi-sample synchronous friction and wear test device is disclosed. The friction disc, the grinding head eccentrically arranged above the friction disc and the Z-direction loading device assembled on the grinding head, the friction disc is composed of the disc body and the test pieces fixed on it, so the disc body of the friction disc is used as the installation test piece The movable seat of the piece, the corresponding grinding head becomes the reference part for the test. During the test, the sample piece is driven to revolve by the driving device, and the Z-direction loading device will press the grinding head on the sample piece. The up-sampling is connected to the friction sensor to collect the friction data between the friction plate and the grinding head during the test, and the test is collected through the resistor plate attached to the friction plate, the power supply and signal acquisition circuit connected to the friction plate and the friction plate Real-time current data during the process, and transmit the friction data and current data to the computer, and the computer calculates the friction coefficient of the friction disc. But because the friction disc is always rotating during the whole test process, it is not convenient to install corresponding sensors on the friction disc to measure the required physical quantities. Even if a sensor is installed on the friction disc, the measurement structure is not very accurate, such as installing The dynamic torsion sensor on the rotating shaft of the friction disc is affected by the output torque of the drive device, and the measured friction torque will be very inaccurate; when the temperature on the friction disc needs to be measured, a contact temperature sensor cannot be installed on the friction disc, and The measurement accuracy of the non-contact temperature sensor is too low; when studying the influence of the electric field on the friction and wear of the friction disc, the electric field cannot be directly applied to the friction disc. The movement on the surface will add another friction pair, which will interfere with the friction pair formed by the friction disc and the grinding head, so that the accuracy of the detection results will be reduced; during the friction and wear process, a friction contact potential will be generated on the friction surface. The performance of friction and wear has a great impact, and when studying the influence of magnetic field on friction and wear, an induced potential will also be generated in the friction pair. Also because the friction disc is always rotating, it is impossible to directly measure the distance between the friction disc and the grinding head. The frictional contact potential and induced potential. In short, since the friction disc is rotating, it is impossible to directly install a sensor on the friction disc to measure the required physical quantity, and it is also impossible to apply an electric field on the disc. Even if a conductive slip ring can be used, it will affect the accuracy of the measurement and cannot be obtained correctly. Therefore, the existing friction and wear test methods have inaccurate measurement results and low accuracy of measurement data.

Contents of the invention

The object of the present invention is to provide a friction testing machine, aiming at solving the problem of inaccurate measurement structure of friction and wear test in the prior art caused by the friction disc constantly rotating.

In order to achieve the above object, the technical scheme of friction testing machine among the present invention is as follows:

Friction testing machine, including a fixed seat for installing a disc-shaped fixed test piece or a fixed reference piece and a movable seat for installing a moving test piece or a moving reference piece. The movable seat is connected with a drive for driving the movable seat relative to the fixed seat Drives that move along straight or curved trajectories.

The driving device includes a horizontally arranged cross slide table with an X-direction slide table and a Y-direction slide table, and an output element for driving the X-direction slide table to move in the X direction and the Y-direction slide table to move in the Y direction.

The output unit is a servo motor.

A Z-direction loading device for driving the movable seat to move in the Z direction is provided between the movable seat and the cross slide table. The Z-direction loading device includes a base that moves with the cross slide table in the X and Y directions and a pedestal connected to the movable seat. output.

The Z-direction loading mechanism also includes a lead screw that is rotatably mounted on the base around the rotation axis extending in the Z direction and a screw nut that is matched with the lead screw and mounted on the base in anti-rotation. The output end of the Z-direction loading device is fixed to the screw nut. even.

The movable base is provided with an elastic buffer mechanism for applying an elastic damping force to the moving test piece or the moving reference piece, which faces away from the Z-direction loading device.

The movable seat is provided with a pressure sensor for detecting the Z-direction loading force exerted by the Z-direction loading device on the moving test piece or the moving reference piece.

The friction testing machine also includes a gantry with a top beam extending along the X direction, and the X guide rail of the cross slide table is fixed on the top beam.

The portal frame is fixedly connected with the fixing seat.

The friction testing machine also includes a temperature sensor for detecting the temperature of the fixed test piece or a fixed reference piece and/or a static torque sensor for detecting the friction torque of the fixed seat when the movable seat moves along the curved track and/or for detecting A teslameter for the magnetic induction of the test piece or reference piece and/or a force sensor for detecting the frictional force on the fixed seat when the movable seat moves along a straight line track.

The invention installs the disk-shaped fixed test piece or fixed reference piece on the fixed seat, installs the moving test piece or the moving reference piece on the movable seat, and drives the movable seat to move along a straight line or a curved track through a driving device. During the wear process, the fixed test piece or the fixed reference piece is fixed, while the moving test piece or the moving reference piece can move on the fixed test piece or the fixed reference piece, but the moving test piece or the moving reference piece itself does not make a rotary motion, That is, there is no rotating body during the friction and wear test, and the sensor can be directly installed on the moving test piece or the moving reference piece and the fixed test piece or the fixed reference piece without the need for a conductive slip ring to transmit electrical signals, so as to achieve the purpose of corresponding physical quantities. The sensor can also be a contact sensor, thereby solving the problem of inaccurate measurement results of the friction and wear test in the prior art caused by the continuous rotation of the friction disc.

Description of drawings

Fig. 1 is the structural representation of friction testing machine in the embodiment of the present invention;

Fig. 2 is a schematic diagram of the system composition of the control device in the embodiment of the present invention;

Fig. 3 is a structural schematic diagram of the connection between the Z-direction loading device and the movable seat in Fig. 1;

Fig. 4 is a schematic diagram of the working principle of the embodiment of the present invention to realize the measurement of temperature, contact potential, friction potential and induced potential;

Fig. 5 is a schematic diagram of the working principle of the embodiment of the present invention in realizing the friction and wear test of the applied electric field and the applied magnetic field.

detailed description

The embodiment of friction testing machine among the present invention: as shown in Figure 1 to Figure 5, this friction testing machine comprises movable seat 1 and fixed seat 2 that are arranged up and down oppositely, movable seat 1 is mainly made of the movable test piece 101 of mounting pin shape. It consists of fixtures. The fixed seat 2 is mainly composed of a transmission shaft of a disc-shaped fixed test piece 201 coaxially installed. The fixed seat 2 is fixedly connected with a gantry 102 with a top beam 1021 through a base 202 and a test bench 203. The gantry 102 Between the top beam 1021 and the movable seat 1, there is a driving device that can drive the movable seat 1 to move along the circular curved track and the linear reciprocating movement track in the horizontal plane of the X and Y directions, and to apply a Z-direction loading force to the movable seat 1 The Z-direction loading device, in which the driving device includes a horizontally arranged cross slide with an X-direction slide 1041 and a Y-direction slide 1042, and is used to drive the X-direction slide 1041 to move in the X direction, and the Y-direction slide 1042 to move in the Y direction. The output element 105 that moves in the direction, the X-direction rail of the cross slide is fixed on the top beam 1021, the X-direction slider is fixed on the Y-direction rail, the Y-direction rail is fixed on the base of the Z-direction loading device, and the output element 105 is a servo motor; the Z-direction loading device includes a base that moves with the cross slide in the X and Y directions, an output end 1032 connected to the movable seat 1, and a screw transmission mechanism arranged between the base and the output end 1032, In the screw transmission mechanism, the lead screw 1033 is rotated and assembled on the base by the Z-direction servo motor 1035 around the rotation axis extending in the Z direction. The screw nut 1034 cooperates with the lead screw 1033 and is assembled on the base. It is a Z-direction sliding table fixed on the screw nut 1034, and an elastic buffer mechanism 106 and a pressure sensor 107 are installed between the output end 1032 of the Z-direction loading device and the movable seat 1. The elastic buffer mechanism 106 is used for moving The test piece 101 applies a downward damping force, and the pressure sensor 107 is used to measure the Z-direction loading force exerted on the moving test piece 101 by the Z-direction loading device.

In the friction and wear test, when it is necessary to measure the temperature, contact potential, friction potential and induced potential of the moving test piece 101 and the fixed test piece 201, the upper temperature sensor 2041 and the lower temperature sensor can be installed on the moving test piece 101 and the fixed test piece 201 respectively. Temperature sensor 2042, lead wires from driven test piece 101 and fixed test piece 201 respectively, and then connect voltage sensor 205 in series between the two lead wires to measure contact potential, friction potential and induced potential.

When carrying out the friction and wear test of the applied electric field and the applied magnetic field, the moving test piece 101 and the fixed test piece 201 are connected in series to an external power supply 206, so as to apply an external force to the friction pair between the moving test piece 101 and the fixed test piece 201. Electric field; electromagnetic coil 207 can also be installed on the moving test piece 101, and after applying DC or AC, an external magnetic field will be applied on the friction pair between the moving test piece 101 and the fixed test piece 201. A Tesla meter is installed on the moving test piece 101 to measure the change of the magnetic induction intensity on the fixed test piece 201 during the moving process of the moving test piece 101, and a current sensor can also be installed on the moving test piece 101 to measure the movement of the moving test piece 101 on the fixed test piece 201. induced current change.

Driven by the driving device, when the movable seat 1 drives the moving test piece 101 to move in a circular curve on the fixed test piece 201, in order to measure the friction torque that the fixed test piece 201 receives during the frictional movement of the moving test piece 101, it can be A static torque sensor is installed on the fixed seat 2; when the movable seat 1 drives the moving test piece 101 to reciprocate along a straight line track at a fixed time, it is used to measure the friction force that the fixed test piece 201 receives during the frictional movement of the moving test piece 101 , the friction sensor can be installed on the fixed seat 2.

The friction testing machine also includes a control device for controlling the action of the cross slide table and the Z-direction loading device. The control device includes an industrial control computer, a data acquisition card, a motion control card and an I/O control board. Control software for data acquisition, X and Y axis plane curve motion control, Z axis loading control and other controls. During use, friction sensors, temperature sensors, voltage sensors 205, current sensors, static torque sensors, etc. The transmitter transmits the detection signal to the data acquisition card, and the data acquisition system software regularly collects data on various physical quantities in the test process through the data acquisition card. Other control equipment needed for friction equipment can be controlled through I/O control board.

During the friction and wear test, the fixed test piece 201 is installed on the fixed seat 2 and fixed, the Z-direction loading device is under the control of the control device, and the Z-direction servo motor 1035 pushes the output end 1032 of the Z-direction loading device through the lead screw 1033 After moving down, when the moving test piece 101 and the fixed test piece 201 are in contact, the data acquisition system can measure the Z-direction load between the moving test piece 101 and the fixed test piece 201 through the pressure sensor 107, and transmit the measured value to the control device. When the Z-direction load reaches the set value, the control device controls the Z-direction servo motor 1035 to stop moving; when the Z-direction load is less than the set value, the control device controls the Z-direction servo motor 1035 to rotate again and continue loading until the Z-direction load reaches the set value. When the value is fixed, it stops again, so as to realize the dynamic loading of the loading force. The X-direction movement and Y-direction movement of the cross slide table can be moved in a plane circular curve under the control of the control device, so that the movable seat 1 drives the moving test piece 101 on the cross slide table to perform circular motion around the Z-direction of the fixed test piece 201 (but does not rotate around its own axis), realizing the pin-disk friction and wear test. A static torque sensor is installed under the fixed fixed test piece 201 to improve the measurement accuracy of the friction torque. During the whole test process, the fixed test piece 201 and the moving test piece 101 have no rotational movement, so there is no need for a conductive slip ring to transmit electrical signals, and it is convenient to arrange various sensors on the moving test piece 101 and the fixed test piece 201 to realize the required signal data. Acquisition and measurement are also convenient for applying electric and magnetic fields on the friction pair for friction and wear tests.

In addition, the control software in the control device can also control the reciprocating movement of the cross slide along a linear trajectory, thereby realizing the reciprocating friction and wear test between the moving test piece 101 and the fixed test piece 201 .

In the present embodiment, the fixed test piece 201 in the friction testing machine does not move, and the circular motion of the moving test piece 101 can carry out the pin-disc friction and wear test, and a static torque sensor can be used without a bearing support and no no-load rotational torque, which reduces the friction and wear test. Interference and cost improve the measurement accuracy; the moving test piece 101 itself does not rotate, and a temperature sensor can be installed on the moving test piece 101, and a temperature sensor can also be arranged on the fixed test piece 201; because the moving test piece 101 and the fixed test piece 201 They do not rotate around their respective central axes, so it is convenient to measure the contact potential and triboelectric potential of the friction interface between the two, and it is convenient to apply voltage and perform friction and wear tests under external electric field and external magnetic field; When the coil is subjected to an applied magnetic field pin-axis type friction and wear experiment, a Tesla meter can be arranged on the fixed test piece 201 to measure the magnetic field change on the fixed test piece 201 during the movement process, and a current sensor can also be arranged on the fixed test piece 201 Detect the induced current; it is convenient to observe the movement and distribution of wear debris on the fixed test piece 201 during the friction and wear process, and it is convenient to collect wear debris; when the static torque sensor is replaced by a force sensor, the dynamic test piece 101 can be controlled to perform reciprocating motion and friction Wear test and fretting friction and wear test; the X and Y direction plane curve motion control in the control software drives the X direction slide table, The interpolation movement of the Y-direction sliding table can drive the Z-direction loading device, the movable seat and the moving test piece on it to produce circular arc movement. The speed of movement and the radius of the arc can be set in the numerical control software parameters. X, Y The axis plane curve motion control part controls the circular movement of the braking specimen on the friction plane of the fixed specimen, and the Z-axis loading control system controls the constant loading force between the braking specimen and the fixed specimen, thus realizing the pin-disk Friction and wear test.

In the above embodiments, the fixed test piece is installed on the fixed seat, and the movable test piece is installed on the movable seat. In other embodiments, the movable reference piece can also be installed on the movable seat, and the fixed reference piece can also be installed on the fixed seat. Both the test piece and the fixed reference piece need to be disc-shaped to provide a friction surface for the moving test piece or the moving reference piece and to facilitate the installation of various sensors, so that the dynamic test piece-fixed reference piece, the moving reference piece-fixed test can be realized. test piece, moving reference piece-fixed reference piece, and the test requirements of moving test piece-fixed test piece in the above-mentioned embodiments, for the test of moving reference piece-fixed reference piece, the test piece can be positioned on the fixed seat and the movable seat by other structures between.

In the above embodiments, the output elements used to drive the X-direction sliding table and the Y-direction sliding table are servo motors. In other embodiments, the servo motors can also be replaced by manual drive mechanisms, oil cylinders, and air cylinders.

In the above embodiments, the part used to drive the movable seat to move along the curved track in the driving mechanism is a cross slide. In other embodiments, the cross slide can also be replaced by an eccentric wheel, a connecting rod mechanism, etc. After the test piece or the moving reference piece is installed eccentrically on a rotary body, the corresponding control device can be removed, because the control device in the above embodiment is mainly to drive the moving test piece to move along the circular curve through the cross slide table, so in If the moving test piece is installed eccentrically on the revolving body, the moving test piece can move along the circular curve track driven by the revolving body without the need for control device to control.

In the above-mentioned embodiments, the transmission mechanism that realizes Z-direction loading in the Z-direction loading device is a screw transmission mechanism, and the screw transmission mechanism is driven by a Z-direction servo motor. In other embodiments, the Z-direction servo motor can also be manually , hydraulic motors, etc., and the screw transmission mechanism can also be replaced by cylinders, hydraulic cylinders, electric push rods, etc.

In the above-mentioned embodiments, the fixed seat is connected with the driving device through the gantry to ensure the integrity of the entire friction testing machine. In other embodiments, the fixed seat and the driving device may not be connected to each other, that is, the fixed seat directly It is placed on the ground, and the driving device is also relatively independently installed on the ground, so that the relatively independent arrangement of the movable seat and the fixed seat is realized.

In the above embodiments, the moving test piece is in the shape of a pin. In other embodiments, the moving test piece can also be in the shape of a disk, so as to realize the disk-disk friction and wear test.

Claims (9)

1. The friction testing machine is characterized in that it comprises a fixed seat for installing a disk-shaped fixed test piece or a fixed reference piece and a movable seat for installing a moving test piece or a moving reference piece. The driving device that the movable seat moves along a straight line or a curved track relative to the fixed seat so that the moving test piece or the moving reference piece itself does not make a rotary motion. The sliding table and the output element used to drive the X-direction sliding table to move in the X direction, and the Y-direction sliding table to move in the Y direction. 2. The friction testing machine according to claim 1, characterized in that the output element is a servo motor. 3. The friction testing machine according to claim 1, wherein a Z-direction loading device for driving the movable seat to move in the Z direction is provided between the movable seat and the cross slide table, and the Z-direction loading device includes a cross slide table The base that moves in the X and Y directions and the output terminal connected to the movable base. 4. The friction testing machine according to claim 3, characterized in that, the Z-direction loading device further comprises a lead screw mounted on the base in rotation around a rotation axis extending in the Z direction, and a lead screw that is matched with the lead screw and mounted on the base without rotation. The nut on the seat, the output end of the Z-direction loading device is fixedly connected with the nut. 5. The friction testing machine according to claim 3, characterized in that, the movable seat is provided with an elastic buffer mechanism for applying an elastic damping force to the moving test piece or the moving reference piece, which faces away from the Z-direction loading device. 6 . The friction testing machine according to claim 3 , wherein the movable seat is provided with a pressure sensor for detecting the Z-direction loading force exerted by the Z-direction loading device on the moving test piece or the moving reference piece. 7. The friction testing machine according to claim 1, characterized in that, the friction testing machine further comprises a gantry with a top beam, the top beam extends along the X direction, and the X guide rail of the cross slide is fixed on the top beam. 8. The friction testing machine according to claim 7, wherein the gantry is fixedly connected with the fixing seat. 9. The friction testing machine according to any one of claims 1 to 8, characterized in that, the friction testing machine also includes a temperature sensor for detecting the temperature of the fixed test piece or the fixed reference piece and/or for testing the temperature of the movable seat A static torque sensor that detects the frictional torque on the fixed seat when moving along a curved track and/or a Tesla meter that detects the magnetic induction of a fixed test piece or a fixed reference piece and/or that detects when the movable seat moves along a straight line track The force sensor of the frictional force on the fixed seat.