CN103868846B - Frictional Factor of Electric Brush testboard and measuring method thereof - Google Patents

Abstract

The utility model relates to a brush friction coefficient testing platform and a measuring method thereof, relating to a friction coefficient measuring device and a measuring method thereof. In order to solve the problem of low measurement accuracy of the current brush dynamic friction coefficient under high-speed conditions. The test bench includes test fixtures and control systems. The test tool adopts the torque sensor to connect vertically with the pressure sensor through the lever arm, the pressure sensor is connected with the brush clamping tool and the brush under test inside, the brush clamping tool is installed on the upper part of the copper inlaid turntable, and the motor is dragged to make the copper inlaid The turntable rotates; the upper part and the lower part of the brush clamping tooling are connected by threads; the lever is a telescopic lever. The control system rotates the drag motor and collects the signals of the pressure sensor and torque sensor; during measurement, the brushes are brought into contact with the copper inlaid turntable, and the thread and the arm lever are adjusted so that the pressure sensor readings are within the specified range; the control system according to the measurement The obtained data is used to calculate the friction coefficient of the tested brush. It is used to measure the coefficient of dynamic friction of brushes under high-speed conditions.

Description

Brush Friction Coefficient Test Bench and Its Measuring Method

technical field

The invention relates to a friction coefficient measuring device and a measuring method thereof, in particular to a brush friction coefficient testing platform and a measuring method thereof.

Background technique

A brush is a conductive component that makes sliding contact with a moving part to form an electrical connection. The brush is used on the commutator or slip ring as a sliding contact body for importing and exporting current. It has good electrical conductivity, thermal conductivity and lubricating properties, and has certain mechanical strength and reversible spark instinct. Almost all DC motors, as well as commutated motors, use brushes, which are an important part of the motor. Since the brushed DC motor requires good lubricity, the friction coefficient of the brush is an important parameter for the performance of the brush.

At present, the measurement of the friction coefficient is mainly carried out by measuring the positive pressure and the friction force, and the general measurement of the dynamic friction coefficient is measured under the condition of low speed. For the electric brush, the relative movement speed between the electric brush and the slip ring is very fast, and the measuring accuracy rate of the device and the method using the existing method is very low.

Contents of the invention

The purpose of the present invention is to solve the problem that the current device and method for measuring the dynamic friction coefficient have low measurement accuracy of the brush dynamic friction coefficient under high-speed conditions. The present invention provides a brush friction coefficient test bench and its measurement method.

The brush friction coefficient test bench of the present invention, the test bench includes a test tool and a control system;

The test tooling includes support base, torque sensor, lever arm, pressure sensor, brush clamping tooling, copper inlaid turntable, radial bearing and drag motor;

The test bench support seat is a three-layer support seat, and a torque sensor is arranged on the top layer of the test bench support seat. Surface fixed connection,

The brush mounting tool is divided into an upper part and a lower part, and the upper part and the lower part are connected by threads; the lower surface of the pressure sensor is fixedly connected with the upper part of the brush card mounting tool, and the lower surface of the pressure sensor is connected by The spring is connected to one side of the brush under test in the brush mounting tooling,

A drag motor is arranged on the middle layer of the support base of the test bench, and the motor output shaft of the drag motor is connected to the center of the copper-inlaid turntable through a radial bearing, and drives the copper-inlaid turntable to rotate;

The copper-inlaid turntable is set on the middle layer of the support seat of the test bench, and the other side of the brush to be tested in the brush clamping tool is set above the copper-inlaid turntable;

The speed control signal output end of the control system is connected to the speed control signal input end of the drive motor, the torque signal output end of the torque sensor is connected to the torque signal input end of the control system, and the positive pressure signal output end of the pressure sensor is connected to the positive pressure signal output end of the control system. Pressure signal input connection.

The lever is a telescopic lever.

The control system includes a torque signal test unit, a positive pressure signal test unit, a signal acquisition and conditioning unit, a control and processing unit, and a communication unit;

The torque signal testing unit is used to receive the torque signal measured by the torque sensor;

A positive pressure signal testing unit, configured to receive the positive pressure signal measured by the pressure sensor;

The signal acquisition and conditioning unit is used to sample the received torque signal and positive pressure signal, condition the sampled signal, and send it to the control and processing unit;

The control and processing unit is used to control the rotation of the dragging motor, and is also used to select the torque signal and positive pressure signal with stable speed, and calculate the dynamic friction coefficient at the corresponding moment according to the torque signal and positive pressure signal, and then calculate the dynamic friction coefficient Calculate the average value, and the average value is the coefficient of kinetic friction of the tested brush;

The communication unit is used for data exchange between the control and processing unit and the host computer.

The torque sensor is realized by a loaded dynamometer.

The diameter of the copper inlaid rotating disk is 60cm.

Based on the measurement method of the brush friction coefficient test bench, the method may further comprise the steps:

Step 1: Initially calibrate the torque sensor using a calibration component; the calibration component includes a calibration lever and a weight;

Step 2: Adjust the length of the arm lever so that the brush clamping tool with the brush under test is in a suspended state, and make the pressure indication of the pressure sensor zero; then, adjust the length of the arm lever so that it is mounted on The tested brush in the brush mounting tool is in contact with the copper inlaid turntable), and then adjust the thread of the brush mounting tool so that the reading of the pressure sensor is within 15kPa-35kPa;

Step 3: The control system powers up the drag motor to make the drag motor start slowly. When the drag motor starts to rotate at a steady speed, the control system controls the pressure sensor and torque sensor to start measurement, and calculates the friction coefficient of the tested brush .

The beneficial effect of the present invention is that the test bench of the present invention has a scientific and reasonable structure, simple and convenient operation, can be used to accurately measure torque signals and positive pressure signals, and calculate and output the dynamic friction coefficient of the tested brush in real time. According to actual production needs, the test bench of the present invention improves the traditional test bench, and can measure the dynamic friction coefficient between the electric brush and the brass material item under high-speed conditions. It can truly reflect the lubrication performance of the brush under working conditions. During this process, the data collection and adjustment are completed, and the all-round automatic monitoring of the normal pressure and friction torque is realized.

The measurement method of the test bench of the present invention can truly display the dynamic friction coefficients of various types of brushes, realize the real-time output of the measurement and calculation results of various types of brushes, have strong anti-interference ability, and can be true, accurate and real-time To reflect the lubricating performance of the brush. Experiments show that the accuracy of the brush friction coefficient measured by the invention is increased by 20%.

The invention provides automatic equipment guarantee for improving the motor manufacturing process, reducing the failure rate of the motor, reducing the cost of human resources, realizing low-carbon environmental protection, and the like.

Description of drawings

Fig. 1 is a structural schematic diagram of a test fixture of a brush friction coefficient test bench according to the present invention.

Fig. 2 is a schematic diagram of the principle of the control system of the brush friction coefficient test bench according to the present invention.

detailed description

Specific embodiment one: this embodiment is described in conjunction with Fig. 1, the brush friction coefficient test bench described in this embodiment, the test bench includes a test tool and a control system;

The test tooling includes a support base 1, a torque sensor 2, a lever lever 3, a pressure sensor 4, a brush mounting tool 5, a copper inlaid turntable 6, a radial bearing 7 and a drag motor 8;

The test bench support seat 1 is a three-layer support seat, and a torque sensor 2 is arranged on the top layer of the test bench support seat 1, and the output shaft 2-1 of the torque sensor 2 is vertically connected with the top of the arm bar 3, and the arm bar The bottom end of 3 is fixedly connected with the upper surface of pressure sensor 4,

The brush mounting tool 5 is divided into an upper part and a lower part, and the upper part and the lower part are connected by threads; the lower surface of the pressure sensor 4 is fixedly connected with the upper part of the brush card mounting tool 5, and the pressure sensor 4 The lower surface of the brush is connected to one side of the brush under test in the brush mounting tooling 5 through a spring,

The middle layer of the test bench support seat 1 is provided with a drag motor 8, and the motor output shaft 8-1 of the drag motor 8 is connected with the center of the copper-inlaid turntable 6 through the radial bearing 7, and drives the copper-inlaid turntable 6 to rotate;

The copper-inlaid turntable 6 is arranged on the middle layer of the support seat 1 of the test bench, and the other side of the brush to be tested in the brush clamping tool 5 is arranged above the copper-inlaid turntable 6;

The speed control signal output end of the control system is connected with the speed control signal input end of the drive motor 8, the torque signal output end of the torque sensor 2 is connected with the torque signal input end of the control system, and the positive pressure signal output end of the pressure sensor 4 is connected with the control Connect to the positive pressure signal input of the system.

The lever arm 3 is a retractable arm lever.

This embodiment is mainly used for testing the brush friction performance of a brushed DC motor. Friction The brush friction torque is measured with a torque sensor. The pressure sensor is connected to the brush through a spring, so the pressure change on the brush can be monitored in real time. In order to ensure that the vibration of the copper plate is as small as possible when the copper plate is rotating, the connecting bearing between the motor and the copper plate needs to use a radial bearing.

The output shaft 2-1 of the torque sensor locks the lever arm so that it maintains a vertical position. The lever arm is telescopic and divided into upper and lower parts, and the length can be adjusted. After the adjustment is completed, the top wire can be tightened to fix it.

The pressure sensor 4 is connected with the tested brush through a spring, and is used for measuring the positive pressure on the brush.

Specific embodiment 2: This embodiment is described in conjunction with FIG. 2 . This embodiment is a further limitation of the brush friction coefficient test bench described in Specific Embodiment 1. The control system includes a torque signal test unit and a positive pressure signal test unit. , signal acquisition and conditioning unit, control and processing unit and communication unit;

a torque signal testing unit, configured to receive the torque signal measured by the torque sensor 2;

A positive pressure signal testing unit, configured to receive the positive pressure signal measured by the pressure sensor 4;

The signal acquisition and conditioning unit is used to sample the received torque signal and positive pressure signal, condition the sampled signal, and send it to the control and processing unit;

The control and processing unit is used to control the rotation of the dragging motor 8, and is also used to select a torque signal and a positive pressure signal with stable speed, and calculate the dynamic friction coefficient at the corresponding moment according to the torque signal and positive pressure signal, and then calculate the dynamic friction coefficient The coefficient is averaged, and the average value is the kinetic friction coefficient of the brush under test;

The communication unit is used for data exchange between the control and processing unit and the host computer.

In this embodiment, the control and processing unit divides the torque by the torque arm lever according to the torque generated by the positive pressure and friction of the brush under test to the center of rotation, combined with the distance from the brush under test to the center of rotation of the copper-inlaid turntable 6 The length is used to calculate the friction force. The friction force divided by the normal pressure is the coefficient of friction.

Embodiment 3: This embodiment is a further limitation of the brush friction coefficient test bench described in Embodiment 3, and the torque sensor 2 is realized by a loaded dynamometer.

Embodiment 4: This embodiment is a further limitation of the brush friction coefficient test bench described in Embodiment 3, and the diameter of the copper-embedded turntable 6 is 60 cm.

In order to simulate the working condition of the brush under actual conditions, it is necessary to ensure that the contact between the copper plate and the brush moves approximately in a straight line, so the diameter of the copper plate is designed to be 60cm.

Embodiment 5: This embodiment is further limited by the method for measuring the brush friction coefficient test bench described in Embodiment 1. The method includes the following steps:

Step 1: Initially calibrate the torque sensor using a calibration component; the calibration component includes a calibration lever and a weight;

Step 2: Adjust the length of the arm lever 3, so that the brush clamping tool 5 equipped with the brush to be tested is in a suspended state, and make the pressure indication of the pressure sensor be zero; then, adjust the length of the arm lever 3, Make the brush under test installed in the brush clamping tool 5 contact with the copper inlaid turntable 6, and then adjust the thread of the brush clamping tool 5 so that the reading of the pressure sensor is within 15kPa-35kPa;

Step 3: The control system powers up the drag motor to make the drag motor start slowly. When the drag motor starts to rotate at a steady speed, the control system controls the pressure sensor and torque sensor to start measurement, and calculates the friction coefficient of the tested brush .

The torque sensor in this embodiment needs to be calibrated with a calibration lever and a weight before use. The calibration lever is set on the output shaft of the dynamometer, and the output shaft passes through the center of the calibration lever, and the weight is suspended at one end of the calibration lever.

After the electric brush clamping tooling 5 fixes the position of the electric brush, extend the lever arm to make the electric brush contact with the copper-embedded rotating disk 6 of the middle layer through the opening of the support seat 1 .

The dragging motor 8 is installed on the top floor of the supporting base 1, and the power output shaft 8-1 of the dragging motor 8 is connected with the copper-embedded turntable 6 through a radial bearing, and the dragging turntable rotates.

Make the brush mounting tool 5 equipped with the brush to be tested in a suspended state, so as to perform positive pressure zero adjustment, and remove the influence of the brush mounting tool and brush gravity on pressure calibration.

Claims (4)

1. Brush friction coefficient test bench, said test bench includes test tooling and control system; The test tooling includes a test bench support seat (1), a torque sensor (2), a lever lever (3), a pressure sensor (4), a brush card mounting tool (5), a copper inlaid turntable (6), a radial bearing ( 7) and drag motor (8); The test bench support seat (1) is a three-layer support seat, and a torque sensor (2) is arranged on the top layer of the test bench support seat (1), and the output shaft (2-1) of the torque sensor (2) and the moment arm The top end of the rod (3) is vertically connected, and the bottom end of the moment arm rod (3) is fixedly connected with the upper surface of the pressure sensor (4), The brush mounting tool (5) is divided into an upper part and a lower part, and the upper part and the lower part are connected by threads; the lower surface of the pressure sensor (4) is fixed to the upper part of the brush mounting tool (5) connected, and the lower surface of the pressure sensor (4) is connected to one side of the brush under test in the brush clamping tooling (5) through a spring, A drag motor (8) is arranged on the middle layer of the test bench support seat (1), and the motor output shaft (8-1) of the drag motor (8) passes through the radial bearing (7) and the copper inlaid turntable (6). The centers are connected and drive the copper inlaid turntable (6) to rotate; The copper-inlaid turntable (6) is arranged on the middle layer of the test bench support (1), and the other side of the brush to be tested in the brush mounting tool (5) is arranged above the copper-inlaid turntable (6); The output end of the speed control signal of the control system is connected with the input end of the speed control signal of the drag motor (8), the output end of the torque signal of the torque sensor (2) is connected with the input end of the torque signal of the control system, and the positive end of the pressure sensor (4) The pressure signal output end is connected with the positive pressure signal input end of the control system; The lever arm (3) is a telescopic lever arm; It is characterized in that: the control system includes a torque signal test unit, a positive pressure signal test unit, a signal acquisition and conditioning unit, a control and processing unit, and a communication unit; A torque signal testing unit, configured to receive the torque signal measured by the torque sensor (2); A positive pressure signal testing unit, configured to receive the positive pressure signal measured by the pressure sensor (4); The signal acquisition and conditioning unit is used to sample the received torque signal and positive pressure signal, condition the sampled signal, and send it to the control and processing unit; The control and processing unit is used to control the rotation of the dragging motor (8), and is also used to select a torque signal and a positive pressure signal with stable speed, and calculate the coefficient of dynamic friction at a corresponding moment according to the torque signal and the positive pressure signal, and then obtain the The coefficient of dynamic friction is averaged, and the average value is the coefficient of dynamic friction of the tested brush; The communication unit is used for data exchange between the control and processing unit and the host computer. 2. The test bench for brush friction coefficient according to claim 1, characterized in that: the torque sensor (2) is realized by a loaded dynamometer. 3. The test bench for brush friction coefficient according to claim 1, characterized in that: the diameter of the copper inlaid turntable (6) is 60cm. 4. based on the measurement method of the said brush friction coefficient test bench of claim 1, it is characterized in that: said method comprises the steps: Step 1: Initially calibrate the torque sensor using a calibration component; the calibration component includes a calibration lever and a weight; Step 2: Adjust the length of the lever arm (3), so that the brush mounting tool (5) with the brush to be tested is in a suspended state, and make the pressure indication of the pressure sensor zero; then, adjust the arm lever The length of (3) is such that the tested electric brush installed in the electric brush mounting tooling (5) is in contact with the copper inlaid turntable (6), and then the screw thread of the electric brush mounting tooling (5) is adjusted so that the pressure sensor The indication is within 15kPa-35kPa; Step 3: The control system powers up the drag motor to make the drag motor start slowly. When the drag motor starts to rotate at a steady speed, the control system controls the pressure sensor and torque sensor to start measurement, and calculates the friction coefficient of the tested brush .