GB/T 38285-2019Brakes for motorcycles and mopeds (English PDF)

3.1 Mechanical drum brake

A brake that uses mechanical means to force the brake shoes to contact or separate from the brake ring to create or eliminate the brake function.

3.2 Hydraulic disc brake

The phenomenon that after a brake has water recession, the brake performance is restored due to the humidity drop.

3.12 Drag torque

The residual disc rotation torque when the hydraulic pressure or thrust of a brake is released.

3.13 Caliper sliding resistance

The resistance of floating brake caliper moving on sliding shaft.

4.1 Basic requirements

4.1.1 The brake shall be manufactured according to the product drawings and technical documents approved by the prescribed procedures, in accordance with the provisions of this Standard.

4.1.2 The materials and related parts used for the brake shall meet the requirements of the relevant technical documents.

4.2 Hydraulic disc brake

4.2.1 Brake master cylinder

4.2.1.1 Tightness

The vacuum tightness, pneumatic tightness and hydraulic tightness of the brake master cylinder shall comply with the provisions of QC/T 311.

4.2.1.2 Piston invalid stroke

Invalid stroke is (1.1±0.7) mm at the piston of the master cylinder or the value required by the vehicle manufacturer.

4.2.1.3 Piston reset time

The no-load reset time of the master cylinder piston shall not exceed 0.5s.

4.2.1.4 Followability of oil sump gasket

In the followability test of the oil sump gasket of the brake master cylinder, the liquid level in the oil sump can drop smoothly.

4.2.1.5 Compressive strength

4.2.2.7 Torsional fatigue strength

After the torsional fatigue strength test, the brake caliper shall not produce deformation or damage that affects the performance. There shall be no hydraulic leakage during the entire test.

4.2.2.8 Vibration durability

The vibration durability of the brake caliper shall meet the requirements of QC/T 592.

4.2.2.9 Waterproof performance

The waterproof performance of the brake caliper shall meet the requirements of QC/T 592.

4.2.3 Brake disc

Brake discs for motorcycles and mopeds shall meet the relevant requirements of QC/T 781.

4.2.4 Brake tube

Brake tubes for motorcycles and mopeds shall meet the relevant requirements of GB 16897.

4.2.5 Assembly

4.2.5.1 Tightness

After the assembly is tested for tightness, there shall be no leakage at all connections.

4.2.5.2 Durability

4.2.5.2.1 Endurance at room temperature

After the room temperature endurance test, there shall be no parts damage, no leakage, and the assembly can still work normally.

4.2.5.2.2 Endurance at high temperature

After the high temperature endurance test, there shall be no parts damage, no leakage, and the assembly can still work normally.

4.2.5.2.3 Endurance at low temperature

After the low temperature endurance test, there shall be no parts damage, no leakage, and the assembly can still work normally.

a) Drain the brake fluid from the sample. Close the drain hole. Connect to the vacuum source from the sample cup opening;

b) When the vacuum inside the sample reaches -98kPa±2kPa, turn off the vacuum source. Measure the pressure rise within 5s.

5.1.1.1.2 Air tightness

The air tightness test is carried out as follows:

a) Open the sample cup lid. Drain the brake fluid from the sample. Use the push rod of the driving device to push the brake handle or piston of the sample until push to exceed the maximum initial pressure build-up stroke of the sample;

b) Connect the oil outlet of the sample to the test gas source. Adjust the air source pressure to 50kPa±2kPa. Turn off the air source;

c) Measure the pressure drop of the sample brake cavity within 10s after stabilizing for 3s~5s;

d) Return the push rod of the drive unit to its original position;

e) The sample oil cup cover is assembled to the brake master cylinder according to the actual assembly state;

f) Adjust the air source pressure to 0.5MPa±0.05MPa. Maintain 10s. Observe whether there is air leakage at the sample and the oil cup. When using plastic oil cups for samples, observe whether there are deformations that affect the function.

5.1.1.1.3 Hydraulic tightness

The hydraulic tightness test is carried out according to the following steps:

a) Connect the sample to the load device and pressure measurement device to form a circuit that simulates the state of the real car;

b) Fill the sample oil cup with brake fluid to the upper limit of the oil level to fill the test circuit with brake fluid;

c) Use the push rod of the driving device to push the brake handle or piston of the sample. When the maximum working hydraulic pressure of the sample is established in the brake cavity of the sample, keep the putter position unchanged. After pressure stabilization for 3s~5s, measure the pressure drop of the sample brake cavity within 30s;

d) Use the push rod of the driving device to push the brake handle or piston The test method for the tightness of the bleed screw of the brake caliper shall meet the requirements of QC/T 592.

The test method for the tightness of the connecting thread of the brake pipe of the caliper shall meet the requirements of QC/T 592.

5.1.2.1.5 Tubing connection thread tightness

5.1.2.2 Sliding resistance of caliper body

The test method for the sliding resistance of the caliper body of the floating brake caliper shall meet the requirements of QC/T 592.

5.1.2.3 Drag torque

The drag torque test method for the brake caliper shall meet the requirements of QC/T 592.

5.1.2.4 Clamper body rigidity

The test method for the rigidity of the brake caliper (the amount of deformation of the caliper body) shall meet the requirements of QC/T 592.

5.1.2.5 Compression resistance strength

The test method for the compression resistance strength of the brake caliper shall meet the requirements of QC/T 592.

5.1.2.6 Torque breaking strength

Before the brake is installed on the test stand, there shall be no abnormalities.

No foreign objects such as grease and paint on the brake lining (pad). The friction surface of the brake drum (disc) shall be clean. The installation on the test bench shall be the same as the loading state. The direction of rotation of the brake drum (disk) is consistent with the direction of the motorcycle. The test is carried out according to the following steps:

a) Running-in test at forward direction:

- When the brake disc rotates in the forward direction, the brake caliper shall clamp the brake disc;

- When the brake disc rotates in the backward direction, the brake caliper shall be released at the same time;

- Brake with a braking torque equivalent to 3.4m/s² deceleration;

- The number of braking times is 5000 times (when the braking torque is shall clamp the brake disc;

- When the brake disc rotates in the backward direction, the brake caliper shall be released at the same time;

- Brake at a brake torque equivalent to 5.88m/s² deceleration;

- The number of braking times is 50000 times;

- The braking maintenance time is 0.5s~2.5s.

c) Check whether there is any deformation or damage that affects the performance, and whether there is hydraulic leakage during the entire test.

5.1.2.8 Vibration durability

The test method for the vibration durability of brake caliper shall meet the requirements of QC/T 592.

5.1.2.9 Waterproof performance

The test method for the waterproof performance of brake calipers shall meet the requirements of QC/T 592.

5.1.3 Assembly

5.1.3.1 Tightness

Use the brake handle to move the master cylinder piston forward 3mm ~ 5mm (completely close the orifice). Apply 7MPa±0.2MPa of hydraulic pressure from the brake caliper bleed nozzle to the assembly. Maintain 10s. Check and record the assembly for leaks or damage.

5.1.3.2 Durability at room temperature

5.1.3.2.1 The durability at room temperature shall be tested under the following conditions:

a) Test ambient temperature: room temperature;

b) Maximum brake pressure: 3.4MPa±0.2MPa;

c) Brake stroke of master cylinder: more than 50% of the maximum stroke of the piston;

d) Operating frequency of brake master cylinder piston: 1000 times/h±100 times/h;

e) Action times of brake master cylinder piston: 3 x 10^5 times.

Mm - Maximum total mass set by motorcycle factory, in kilograms (kg); Mo - Kerb mass of motorcycle, in kilograms (kg); RK - Motorcycle wheel rolling radius, in meters (m).

NOTE 1: The test moments of inertia of two-wheeled motorcycles, mopeds and side-wheeled motorcycles are calculated according to formula (A.1).

NOTE 2: When the wheel is a double disc brake, the moment of inertia of each brake test is 0.5 times the calculated value.

The test rotational inertia of the positive three-wheeled moped and the positive three-wheeled motorcycle is first calculated according to formula (A.1). The test moment of inertia of each rear wheel is taken as 0.5 times the calculated moment of inertia of the rear wheel.

A.1.3 Spindle speed

The spindle speed of the inertial test bench is calculated according to formula (A.2).

Where, n - Spindle speed of test bench, in RPM (r/min); v - Motorcycle test initial speed, in kilometers per hour (km/h); RK - Motorcycle wheel rolling radius, in meters (m).

A.1.4 Test instrument accuracy

Instrument accuracy for measuring and recording speed, torque and temperature is ±1%. Control accuracy of torque, temperature is ±2%. The moment of inertia of the inertial test bench shall include the moment of inertia of all rotating parts of the test bench. The accuracy is ±5%. The accuracy of the time intervals which the system moves with is ±10%.

A.2 Test conditions

A.2.1 Wind speed

During the test, the fan is used to cool the brake, and the wind speed is 10m/s. Stop blast cooling during hot decline and water decline tests. […]

A.2.2 Temperature