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Test Condition
A damping force characteristic test was conducted before and
after the bench durability test. As for the damping force
characteristic test, as in the previous report, the combination
test software of Windows Software for 4830 was set up so that
test conditions with different excitation speeds could be
continuously and automatically executed. Similar to JASO C611,
JASO C602 has prescribed excitation speeds of 0.05 m/s, 0.1 m/s,
0.3 m/s, 0.6 m/s, and 1.0 m/s. However, for this specimen,
0.6 m/s and 1.0 m/s were not tested because the damping force
at 0.45 m/s or higher exceeded the testing capacity of the
testing machine. Note that in JASO C602, excitation speeds
other than 0.3 m/s are treated as reference values, and the final
decision is made by the parties involved in the delivery.
Shock absorber
fixture
thermocouple
Compressed air
hose for cooling
Specimen
Shock absorber
fixture
Fig. 4 shows the specimen attached in the testing machine. In
order to measure the temperature of the specimen, a
thermocouple was attached to the outer cylinder surface, and
compressed air was sprayed on the outer cylinder for forced
cooling from the outside.
Fig. 4 Specimen Attached to the Testing Machine
Test Mode: Fatigue and endurance test
Control Signal: Displacement
Waveform: Sine wave
Excitation Speed: 0.05 m/s, 0.1 m/s, 0.3 m/s, 0.45 m/s
Amplitude: ±50 mm
Mean: 0 mm
Repetitions: 10, 20, 60, 90
Ambient Temperature: Room temperature (24 °C)
The damping force characteristic test was performed before and
after the bench durability test. “Windows Software for 4830” for
fatigue and endurance systems was used for the bench
durability tests. The excitation kinetic energy is converted into
thermal energy by the oil within the shock absorber, so the
temperature rises with continuous excitation. In the bench
durability test in accordance with JASO C602, the cooling
system is adjusted so that the temperature of the specimen falls
within the specified temperature range, and the test is
performed within the specified temperature range for the
specified number of cycles. Ideally, the temperature should
always be within the specified temperature range, but this may
require extensive cooling system equipment.
Therefore, the “intermittent operation setting” function of
Windows Software for 4830 was used to perform intermittent
operation, which stops the test temporarily when the specified
temperature is exceeded and restarts it after the temperature
drops. The “intermittent operation setting” function has been
implemented since version 4.15 (February 2023 onward). Even
older versions can be upgraded (for a fee) to add this function.
Fig. 5 shows the intermittent operation setting wizard of the
software. The Monitor TD (signal) was set to the outer cylinder
surface temperature measured by the thermocouple, and the
temperature range was set to 90 °C for pause and 70 °C for test
restart in accordance with the standard (80 ± 10 °C).
Fig. 5 Intermittent Operation Setting Wizard
Table 4 shows the test conditions for the bench durability test.
Compressed air from the laboratory equipment was used as a
cooling device. The temperature signal of the thermocouple
attached to the outer cylinder surface was converted to analog
and connected to the analog input terminal of the 4830
controller.
Test Results
Fig. 6 shows the graph of the number of cycles of the bench
durability test. It can be confirmed that the temperature
remained within the range of 90 to 70 °C up to 1 million cycles.
In addition, there was no significant change in the upper and
lower peak values of the damping force. Therefore, it is
considered that the damping force was not affected by the
temperature change during the test.
50
60
70
80
90
100
-1000
-800
-600
-400
-200
0
200
400
600
800
1000
0 500,000 1,000,000
Temperature [°C]
Damping force [N]
cycles
Damping force Tempreture Temperature Damping force
Fig. 6 Bench Durability Test Cycles Graph
Table 3 Damping Force Characteristic Test Conditions
Intermittent operation
within a certain range of
arbitrary signals is possible.
Test Mode: Fatigue and endurance test
Control Signal: Displacement
Waveform: Sine wave
Excitation Speed: 0.45 m/s
Amplitude: ±25 mm
Mean: 0 mm
Excitation Direction: Vertically erect
Repetitions: 1 x 10
6
Ambient Temperature: Room temperature (24 °C)
External Input Signal Outer cylinder surface (analog input)
Specimen Temperature: 80 ± 10 °C
Cooling Device Compressed air (laboratory equipment)
Temperature Sensor: Type K thermocouple
Table 4 Bench Durability Test Conditions
