QC/T 592-2013 PDF in English
QC/T 592-2013 (QC/T592-2013, QCT 592-2013, QCT592-2013)
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Performance requirements and Bench test methods for Hydraulic brake caliper assembly
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QC/T 592-2013: PDF in English (QCT 592-2013) QC/T 592-2013
AUTOMOBILE INDUSTRY STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
ICS 43.040.40
T 24
Replacing QC/T 592-1999
Performance requirements and bench test methods for
hydraulic brake caliper assembly
ISSUED ON: OCTOBER 17, 2013
IMPLEMENTED ON: MARCH 01, 2014
Issued by: Ministry of Industry and Information Technology of PRC
Table of Contents
Foreword ... 6
1 Scope ... 8
2 Normative references ... 8
3 Terms and definitions... 8
4 Performance requirements ... 9
5 Test methods ... 12
Performance requirements and bench test methods for
hydraulic brake caliper assembly
1 Scope
This standard specifies the terms and definitions, performance requirements, test
methods for the bench test of hydraulic brake caliper assemblies for automobile service
brakes.
This standard applies to the hydraulic brake caliper assembly, for the service brakes of
category M and category N vehicle, whose maximum design total mass as specified in
GB/T 15089 is less than 3500 kg. Other categories of hydraulic brake calipers may
make reference to this standard.
2 Normative references
The following documents are essential to the application of this document. For the dated
documents, only the versions with the dates indicated are applicable to this document;
for the undated documents, only the latest version (including all the amendments) is
applicable to this standard.
GB/T 10125-1997 Corrosion tests in artificial atmospheres - Salt spray tests
GB/T 15089 Classification of power-driven vehicles and trailers
QC/T 316 Bench test methods of fatigue strength for automobile service brake
3 Terms and definitions
The following terms and definitions apply to this standard.
3.1
Required fluid amount
The amount of brake fluid, which is injected to maintain the specified hydraulic
pressure, in the brake caliper.
Note: The unit of required fluid amount is mL.
4.1.2 Low-pressure tightness. Carry out the test, according to 5.1.2. The pressure drop
shall not be greater than 0.34 kPa.
4.1.3 High-pressure tightness. Carry out the test, according to 5.1.3. The pressure drop
shall not be greater than 0.2 MPa.
4.1.4 Bleed screw tightness. Carry out the test, according to 5.1.4. There shall be no
liquid leakage, at the bleed screw.
4.1.5 The tightness of the oil pipe's connection thread. Carry out the test, in accordance
with 5.1.5. There shall be no liquid leakage, at the bolted connection.
4.2 Required fluid amount
Carry out the test, according to 5.2. The required fluid amount of the new brake pads
(with spacers) and metal brake pads of equivalent thickness (without spacers) shall meet
the requirements of product technical conditions.
4.3 Drag torque
Carry out the test, according to 5.3. The maximum value of the drag torque, during the
first rotation of the brake disc, shall not be greater than 5 N • m; the maximum value,
during the 10th rotation, shall not be greater than 3.5 N • m.
4.4 Caliper rigidity
Carry out the test, according to 5.4. The deformation of the caliper, along the axis of
the hydraulic cylinder, shall not be greater than 0.2 mm, OR meet the requirements of
product technical documents.
4.5 Piston return
Carry out the test, according to 5.5. The return amount of the piston shall not be greater
than 0.6 mm, OR meet the requirements of product technical documents.
4.6 Piston sliding resistance
Carry out the test, according to 5.6. The piston sliding resistance shall be in the range
of 70 N ~ 700 N, OR meet the requirements of product technical documents.
4.7 Piston actuation pressure
Carry out the test, according to 5.7. The input pressure, when the piston starts to move,
shall not be greater than 0.10 MPa, OR meet the requirements of product technical
documents.
4.8 Caliper sliding resistance
Carry out the test, according to 5.8. The caliper sliding resistance of the floating brake
caliper shall not be greater than 100 N, OR meet the requirements of the product
technical documents.
4.9 Strength
4.9.1 Torsional fatigue strength. After the test according to 5.9.1, the brake caliper
assembly shall not be deformed or damaged, which affects the performance; there shall
be no hydraulic leakage, during the whole test.
4.9.2 Compressive breaking strength. Carry out the test, according to 5.9.2. The brake
caliper assembly shall be free from leakage, cracks, damage.
4.10 Durability
4.10.1 High-pressure durability.
4.10.1.1 After the test in accordance with 5.10.1, the parts shall not be deformed or
damaged, which affect the performance.
4.10.1.2 The low-pressure tightness and high-pressure tightness, after the test, shall
meet the requirements of 4.1.2 and 4.1.3, respectively.
4.10.2 Working durability.
4.10.2.1 After the test is carried out, according to 5.10.2, it allows wear on the piston,
sealing ring, inner wall of the cylinder bore; BUT there shall be no damage, that affects
the performance.
4.10.2.2 The low-pressure tightness and high-pressure tightness, after the test, shall
meet the requirements of 4.1.2 and 4.1.3, respectively.
4.10.3 Vibration durability.
After the test according to 5.10.3, the brake caliper assembly shall not have damages,
such as damage, cracking, falling off parts, shearing, that affect the performance. The
tightening torque's drop value of threaded parts shall not be greater than 30% of the
lower limit of the torque, which is specified in the product technical documents; there
shall be no leakage, throughout the test.
4.11 Waterproof performance
After the test according to 5.11, there shall be no water intrusion in the cylinder block
and inside the guide pin's dust cover.
4.12 Corrosion resistance
Carry out the test, according to 5.12. The brake caliper assembly shall meet the
5.2.4 Pressurize to 16 MPa or the pressure specified in the product technical documents,
for the 5th time. Close the global valve. Open the liquid volume control valve. After the
liquid level of the liquid volume pipe is stable, record the liquid level height of the
liquid volume pipe, which is the required fluid amount by the system, V0.
5.2.5 Remove the solid metal joint. Connect the brake caliper assembly to the brake oil
pipe. Drain the air in the system. Open the fluid volume control valve. Adjust the liquid
level of the fluid volume pipe to zero. Close the fluid volume control valve.
5.2.6 Repeat operations 5.2.3 and 5.2.4. Record the required fluid amount, V1, of the
system including the brake caliper assembly.
5.2.7 The value, which is obtained by subtracting V0 from V1, is the required fluid
amount of the brake caliper assembly.
5.3 Drag torque
5.3.1 Use a lint-free cloth and a solvent such as acetone, to wipe the friction surface of
the brake disc. Then install the brake disc on the test device. The runout of the end face,
which is measured on the working surface, at 10 mm away from the outer edge of the
brake disc, shall not be greater than 0.05 mm. The parallelism, between the brake disc
and the brake caliper's installation surface, shall not be greater than 0.10 mm.
5.3.2 Fix the brake caliper assembly on the test device, according to the actual vehicle
installation state. Then connect the hydraulic pressure source's pressurized pipeline to
the brake caliper's fluid inlet, to completely drain the air in the system, as shown in
Figure 4.
5.3.3 Retract the piston of the brake caliper assembly, so that the gap, between each
side of the brake pad and the brake disc, is greater than 0.5 mm.
5.3.4 Idle the brake disc. Zero the drag torque measuring device.
5.3.5 Pressurize the brake caliper assembly to 7 MPa. Keep the pressure for 5 s. Then
release the pressure to zero. Repeat 10 cycles.
5.3.6 After placing for 2 min, make the brake disc rotate at (45 ~ 50) r/min. Measure
and record the maximum drag torque, during the 1st and 10th rotation of the brake disc.
5.4 Caliper rigidity
5.4.1 Fix the brake caliper assembly on the mounting bracket. Then connect the
hydraulic pressure source, to the fluid inlet of the brake caliper, to completely drain the
air in the system, as shown in Figure 5.
5.4.2 The measurement point of the deformation of the caliper shall be selected at a flat
part, avoiding the unevenness of the casting surface, to reduce the measurement error.
1 - Air pressure source; 2 - Globe valve; 3 - Pressure gauge; 4 - Brake caliper
(specimen); 5 - Piston limit stop; 6 - Pull pressure sensor; 7 - Thrust device; 8 -
Displacement measuring device
Figure 7 -- Schematic diagram of test device for piston sliding resistance and
starting pressure
5.6.2 Apply air pressure to the brake caliper, to push the piston to move out about 5 mm.
Push the piston back to the original position, through the thrust device, after the pressure
is relieved. This is regarded as one operation cycle. It is carried out 3 cycles in total.
5.6.3 Apply air pressure to the brake caliper, to push the piston to move out about 5 mm.
After the pressure is released, push the piston back 4 mm, at a constant speed of no
more than 0.5 mm/s, through the push rod of the thrust device. Record the maximum
thrust value during this process, which is the piston sliding resistance.
5.7 Piston actuation pressure
After completing the test of 5.6, push the piston back to the original position. Then
slowly pressurize the brake caliper, from the fluid inlet, to move the piston outward
about 1 mm. Record the input pressure, when the piston starts to move.
5.8 Caliper sliding resistance
5.8.1 Install the brake caliper assembly on the test bench, according to the actual vehicle
installation state. Confirm that the brake pads are installed in place. Then connect the
hydraulic pressure source's pressurizing pipeline to the fluid inlet of the brake caliper,
to empty the air in the system, as shown in Figure 8.
5.8.2 Pressurize the brake caliper assembly to 0.5 MPa. Release the pressure to zero,
after maintaining the pressure for 1 s. Repeat this for 3 cycles.
5.8.3 Apply 1 MPa hydraulic pressure, to the brake caliper. Hold this pressure.
5.8.4 Push the fan-shaped simulated disk, through the thrust device, to drive the caliper
to move about 4 mm, as relative to the brake caliper's mounting bracket, to the side near
the mounting surface of the bracket, at a rate of not more than 2.0 mm/s. Then return to
the original position. The above operation is repeated 4 cycles in total. Record the
maximum resistance, during the 4th movement.
shall be as close to a sine wave as possible. At the same time, the brake caliper shall be
braked once a minute; the brake hydraulic pressure is 3.5 MPa; the pressure holding
time is 1 s.
5.10.3.3 The brake caliper shall first be equipped with new brake pads. Vibrate it
continuously for 1.0 x 106 cycles. Then use brake pads in full-wear state to replace it.
Then vibrate it continuously for another 1.0 x 106 cycles.
5.10.3.4 After the test, check whether the specimen is damaged, cracked, parts falling
off and shearing, or other damages, which affect the performance. Measure the
tightening torque of the bracket mounting bolts and the oil pipe connection bolts.
5.11 Waterproof performance (see Figure 9)
5.11.1 Place the brake caliper assembly in an incubator, at (120 ± 5) °C for 70 h.
5.11.2 Take the brake caliper assembly out of the incubator. Place it indoors, to return
to room temperature.
5.11.3 Install the brake caliper on the bracket, according to the actual vehicle installation
state. Connect the pressurizing pipeline of hydraulic pressure source to the fluid inlet
of the brake caliper, to completely exhaust the air in the system.
5.11.4 Apply hydraulic pressure of 3.5 MPa to the brake caliper. Hold the pressure for
5 s. Then release the pressure. After confirming that the brake gap meets the
requirements of the product technical documents, place the brake caliper and the
mounting bracket together into the water tank, as shown in Figure 9. The distance,
between the water surface and the center axis of the brake caliper piston is (300 ± 30)
mm.
5.11.5 Apply 500 brakes to the caliper, at a braking frequency of (0.278 ± 0. 027) Hz
and a brake hydraulic pressure of (3.5 ± 0.15) MPa.
5.11.6 Take the brake caliper assembly out of the water tank. Wipe off the moisture
attached to the surface.
5.11.7 Remove the dust cover and guide pin's protection cover. Check and record
whether there is water intrusion in the inside of the cylinder block and the guide pin's
dust cover.
5.11.8 Replace the brake pads with the brake pads in full-wear state, to repeat the above
test.
5.12 Corrosion resistance
5.12.1 Measure the piston actuation pressure, according to 5.7.
5.12.2 Adjust the axial position of the piston and brake pad, according to the actual
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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