Introduction of friction pair and friction measurement system of automatic four-ball machine (SH120)

November 10, 2020

The extreme pressure and wear resistance tests of lubricants are mainly carried out in the form of four ball friction pairs.
During the test, a steel ball above is fixed in the 1:7 taper hole at the lower end of the spindle through the steel ball chuck, and rotates with the spindle.
The following three steel balls are fixed in the oil box and shall not be rotated or rolled.
The oil box is placed on the torque wheel, and there is a pair of thrust bearing under the torque wheel, so that the upper and lower friction pairs can be aligned automatically in the test process.
The test force is transferred from the piston to the friction pair through the thrust bearing, torque wheel and oil box.
When there is a certain test force between the upper and lower friction pairs and the spindle rotates at a certain speed, a certain friction force will be generated between the upper and lower friction pairs to drive the oil box and torque wheel to rotate together.
In order to measure the friction force, a steel wire is connected to the friction measuring sensor, and the friction measuring sensor transmits the measured signal to the friction measuring display system for digital display and automatic record. Compared with the set friction value, the spindle will automatically stop for protection and alarm display when the set value is exceeded.
The friction pair is heated by a ring heater outside the oil box. When heating is needed, the ring heater is connected to the power supply and the temperaturemeter switch is placed in the open position.
The hot spot is a temperature measuring element, and the measured signal is digitally displayed and automatically recorded by the temperature measurement control system for the friction pair, and compared with the set temperature value, and the comparison signal is fed back to the heater for the closed-loop control of the temperature.
When the actual temperature exceeds the set value, the alarm system will display the alarm.