OEM Automatic blow - off and friction testing machine for testing shock absorber piston

TEST PARAMETERS

- Test machine: INSTRON

- Test stroke: ± 30 mm

- Test speed: 1 mm/s

- Temperature: room temperature

- Test fixture: special made tooling

- Use a tube of 200 mm height

- Effective force on piston must be:

0N, 70N, 150N, 220N, 450N

- The side load calculated as followed:

Side load =Effective force on piston * ((A+B) / A)

- Friction coefficient calculated as followed:

Friction coefficient= Friction / (2*effective force on piston)

Purpose of this test:

to determine the friction for PTFE banded piston when adding different weights. The test is performed with a constant lateral force applied to the piston during the pressure build up over the piston. Automatically get the average friction after testing five cycles.

Test procedure:

1. Cut the tube to the correct length, avoiding any possible deformation caused by clamping the tube. See to it that the tube is burr free.

2. Clean the tube with a brush or cloth in solvent. Check the inside of the tube after cleaning: no scratches contaminants or other things may be present which can have a negative influence on the friction.

3. Impregnate the tube with the correct oil. Check if the inside surface of the tube is fully covered with an oil film.

4. Assemble the piston on the rod and torque the piston on the piston post of the rod.

5. Add spacers between collar welded on rod and the location where the side load needs to be applied. -> is not needed if a groove is made in the rod.

6. Bring the rod – piston assembly in the tube and verify if the friction level is correct and consist over the length of the tube by traveling the piston by hand over the length of the tube. This will also lead to a good oil distribution over the inner surface of the tube.

7. Assemble the tube/rod in the tooling, seeing to it that the tube is well aligned.

8. Connect the load cell to the tensile bench, use if needed for the load cell a side load compensation construction.

Test result:

Competitive advantage:

1.Can check the PTFE banding result

2.Easily operation

3.Machine design according to big shock absorber factory in the world

4.Can test friction and blow-off testing in the same testing machine

5.Can get the curves after testing

Application:

All PTFE banding piston with different size rang from 20mm to 45mm

Picture show