PL160592B2 - Four-ball apparatus for fatigue tests - Google Patents

Abstract

A four-ball device for fatigue tests, composed of a drive motor moving a spindle ended with a holder of the upper ball, the race holder and the race of three lower mobile balls which constitute a sample, where the bottom balls are pressed down against the upper ball by a weighing lever with a weight and a counterweight characterised in that on the holder (7) of the race (8) of the lower balls (3), a vibration pick-up (9) is fixed, which starts the motor (1) at the moment of the commencement of the pitting wear, and also, it has a control-and-measurement system (U) composed of three circuits (O1, O2, O3), where the circuit (O1) is used to measure the temperature of the sample and is composed of a thermostat (10), a push-pull amplifier (11), a voltage-to-frequency converter (12), frequency counter (13), a digital reading panel (14), interface (15) and a computer connector (16) connected in series, the second circuit (O2) is used to measure the vibrations of the tested friction point and control the starting of the drive motor (1) and is composed of vibration pick-up (9), an amplifier (17), threshold discriminators unit (18) and a relay (19) connected in series, and the circuit (O3) is used to count the time or revolutions of the spindle until the time of automatic switching off of the drive motor (1) and is composed of a pulses amplifier (20), a digital reading panel (21), interface (22) and a computer connector (23) connected in series.<IMAGE>

Description

The subject of the invention is a four-ball device for fatigue testing used in the tribological testing system.

Known four-ball fatigue testers include a drive motor that moves a spindle ending with an upper ball holder, against which balls are pressed by three lower movable balls, which constitute the sample, placed in a raceway, which is fixed in the holder, the lower balls being pressed against the upper ball by a loading lever with sinkers and counterweight.

The essence of the invention is a four-ball device for fatigue tests, characterized in that a vibration sensor is attached to the holder of the lower balls' raceways, which turns off the drive motor at the moment pitting wear begins. The control and measurement system consists of three circuits, the first circuit is used to measure the sample temperature, the second circuit is used to measure the vibrations of the test friction junction and control the drive motor shutdown, and the third circuit is used to count the time or spindle revolutions until the motor is automatically turned off. The first circuit consists of a series connection of a thermostat, a push-pull amplifier, a voltage-to-frequency converter, a frequency counter, a digital readout panel, an interface, and a computer connector. The second circuit consists of a series connection of a vibration sensor, an amplifier, a threshold discriminator block, and a relay. The third circuit consists of a series connection of a pulse amplifier, a digital readout panel, an interface and a computer connector.

The subject of the invention is shown in an embodiment in the drawing, which shows a diagram of the device.

The device has a drive motor 1, which drives the spindle ending with the upper ball 2 holder. The upper ball 2 is pressed with three lower 3 movable balls 3, which are the sample, placed in the raceway 8 fixed in the holder 7. Lower 3 balls are pressed against the upper ball 2 by a lever 4, with loading weights 5 and counterweight 6. On the holder 7 of the raceway 8 of the lower balls 3 there is a vibration sensor 9, which switches off the motor 1 at the moment when pitting wear begins. The control and measurement system U consists of three circuits Οι, O2.03. The Oi circuit is used to measure the sample temperature, the O2 circuit is used to measure the test vibration

160 592 node of friction and control of switching off the drive motor 1, and circuit O3 is used to count the time or revolutions of the spindle until the drive motor 1 automatically switches off. Circuit 01 consists of a series connection of a thermostat 10, a push-pull amplifier 11, a converter 12 voltage-frequency, a counter 13 frequencies, 14 digital readout panel, 15 interface and 16 computer interface. The O2 circuit consists of a series connection of a vibration sensor 9, an amplifier 17, a block 18 of threshold discriminators and a relay 19. The O3 circuit consists of a series connection of a pulse amplifier 20, a digital reading panel 21, an interface 22 and a computer connector 23.

160 592

Department of Publishing of the UP RP. Circulation of 90 copies Price PLN 10,000

Claims (1)

Patent claim A four-ball device for fatigue testing, comprising a drive motor that moves a spindle ending with an upper ball holder, a raceway holder and a race of three lower balls, which constitute the sample, the lower balls being pressed against the upper ball by a loading lever with weights and a counterweight, characterized in that on the holder ( 7) of the raceway (8) of the lower balls (3), a vibration sensor (9) is attached, which turns on the motor (1) at the start of pitting wear, and also has a control and measurement system (U) consisting of three circuits (Οι, 02, O3), the circuit (Oi) is used to measure the sample temperature and consists of a series connection of a thermostat (10), a push-pull amplifier (11), a voltage-frequency converter (12), a frequency counter (13), a digital panel (14 ), the interface (15) and the computer interface (16), the second circuit (O2) is used to measure the vibration of the friction test node and to control the activation of the drive motor (1) and consists of s serial connection of the vibration sensor (9), amplifier (17), block (18) of threshold discriminators and a relay (19), while the circuit (O3) is used to count the time or spindle revolutions until the drive motor (1) is automatically switched off (1) and consists of a series connection of a pulse amplifier (20), a digital readout panel (21), an interface (22) and a computer connector (23).