GB/T 33921-2017 in English

《GB/T 33921-2017地下轮胎式采矿车辆 制动系统的性能要求和试验方法》由TC88（全国矿山机械标准化技术委员会）归口，主管部门为中国机械工业联合会。

ChinaStandards.net is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.

This standard is developed in accordance with the rules given in GB/T 1.1-2009.

This standard was proposed by the China Machinery Industry Federation.

This standard is under the jurisdiction of SAC/TC 88 National Technical Committee on Mining Machinery of Standardization Administration of China.







Underground rubber-tyred mining machines -
Performance requirements and test procedures for brake systems

1 Scope

This standard specifies the performance requirements and test procedures for brake systems of underground rubber-tyred mining machines.

This standard is applicable to the following self-propelled rubber-tyred machines used for underground metal mines and other non-coal underground mines and in tunnel engineering:

——underground LHD;

——underground dumper/hauler (underground rubber-tyred mine-car);

——underground utility/service/support machine.

2 Normative references

The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

GB/T 8595 Earth-moving machinery - Operators controls
GB/T 10913 Earth-moving machinery - Determination of ground speed
GB/T 15706 Safety of machinery - General principles for design - Risk assessment and risk reduction
GB/T 21153-2007 Earth-moving machinery - Units for dimensions performance and capacities and their measurement accuracies
ISO 15998 Earth-moving machinery - Machine-control systems (MCS) using electronic components - Performance criteria and tests for functional safety

3 Terms and definitions

For the purposes of this document, the following terms and definitions apply.

3.1

brake system

combination of all parts and components for braking and/or stopping the machine, including brake control, brake actuation system, brake and, if installed, retarder

3.1.1

service brake system

main brake system used to brake and stop the machine

3.1.2

secondary brake system

system that brakes the machine when the service brake system fails

3.1.3

parking brake system

system that keeps the braked machine in place, which may also be part of the secondary brake system

3.1.4

hydrostatic brake system

hydrostatic or other similar driving systems used to meet the requirements of one or more brake systems

3.1.5 Parts and components of brake system

3.1.5.1

brake control

mechanism directly operated by the driver that generates a force transmitted to the brake

3.1.5.2

brake actuation system

all parts and components located between the brake control and the brake and connecting the functions of the two

3.1.5.3

brake(s)

device that directly applies a force to stop the movement of the machine

Note: Types of brakes include friction type, mechanical type, electric type, regenerative device and hydrostatic or other fluid types.

3.1.5.4

common component

component that performs the same function in two or more brake systems

Note: For example, pedals and valves.

3.1.5.5

retarder

energy absorption device commonly used to control machine speed.

3.2

hydrostatic drive system

hydraulic system with the hydraulic motor directly driving the wheels to drive or decelerate the machine

3.3 Mass

3.3.1

operating mass

operating mass of the main engine includes the combination of the following items when heaviest: the working devices and the no-load accessory devices specified by the manufacturer, the driver (75 kg), the fuel tank fully filled with fuel, and other liquid systems (i.e. hydraulic oil, transmission oil, engine lubricating oil, engine coolant) filled to the liquid level specified by the manufacturer

3.3.2

rated paymass (payload)

rated mass that the machine can carry as stated by the manufacturer

3.3.3

gross machine mass

sum of the operating mass and rated paymass of the machine

3.4

stopping distance

s

distance traveled by the machine on the test course from the time when the brake control acts (i.e. the driver applies the brake) to the time when the machine is completely stopped

Notes:

1 The stopping distance is in m.

2 For the braking distance, the reaction time of the driver is not considered, but that of the system is considered.

3.5

mean deceleration

a

average rate of change of machine speed from the moment when the brake control starts to act to the moment when the vehicle stops completely

Note: the average deceleration shall be calculated using Formula (1):

(1)

where,

a——the average deceleration, m/s2;

v——the instantaneous speed of the machine when the brake acts, m/s;

s——the stopping distance, m.

3.6

burnishing

treatment method to make the friction surface of the machine brake reach a good state

3.7

brake system pressure

pressure of fluid at the brake control

3.8

brake application pressure

measured fluid pressure applied to the brake

3.9

modulated braking

braking mode capable of continuously or gradually increasing and decreasing the braking force by operating the brake control

3.10

test course

pavement on which the machine is tested

3.11

cold brakes

When the brake containing friction parts is in one of the following states:

——The brake has not worked for more than 1 h, except for the condition of carrying out applicable performance tests (see clause 7);

——When measuring the temperature of the outer surface of the brake disc or drum, the brake has cooled to 100℃ or below;

——For fully enclosed brakes, including oil-immersed brakes, the temperature measured on the outer surface of the casing closest to the brake is lower than 50℃, or within the range specified by the manufacturer.

3.12

maximum machine speed

maximum speed determined in accordance with GB/T 10913 or equivalent standards

3.13

back throttling

function of applying slight forward or backward force to hydrostatic or other similar driving systems to keep the machine stationary

3.14

safe state

controlled device, process or system being manually or automatically stopped or switched to a mode after the failure of the machine's control system in order to avoid the machine accidental action or the potential danger caused by stored energy release

3.15

underground rubber-tyred mining machines

rubber-tyred machines designed for underground mining operations to carry personnel or materials, or those running on their own power that lift or load materials with additional devices

3.15.1

underground LHD

rubber-tyred machine for loading, lifting, transporting and dumping ores or materials with buckets in underground mines

3.15.2

underground dumper/hauler

rubber-tyred machine with rigid frame or articulated frame that has open carriage and is used for underground transportation and dumping of ore or materials

3.15.3

underground utility/service/support machine

self-propelled mining machines for general purpose that support the main production process of underground mining, such as concrete transport vehicles, concrete injection vehicles, explosive loading truck, mobile elevating work platforms, general service vehicles, skid anchor vehicles, personnel transport vehicles and other vehicles

3.15.4

trailer

a kind of unpowered road vehicle designed such that the technical characteristics may be made normal use of when towed by a tractor and it is used for:

——carrying personnel and/or goods;

——special purposes.

3.16

fully developed deceleration rate

maximum continuous deceleration developed by a machine on the designated slope with a constant gradient with specified test mass, ground conditions and initial machine speed (before deceleration)

3.17

peak deceleration

maximum deceleration obtained during the brake operation test

3.18

machine control system; MCS

assembly necessary to satisfy the system functions, including sensors, signal processing units, monitors, controllers and actuators or several of them

Note: The scope of the system is not limited to the electronic controller, but is defined by the machine-related functions of the whole system, which generally includes electronic, non-electronic and connection equipment. Such system may include mechanical, hydraulic, optical or pneumatic elements/systems.

3.19

brake efficiency

b

percentage of the total braking force applied on the wheels to the weight of the complete machine

3.20

gradient

G

percentage of the elevation difference between two points in the straight line driving direction of a machine to the horizontal distance of the two points, which shall be calculated using Formula (2):

G=tanθ×100% (2)

where,

G——the gradient, %;

θ——the angle of gradient relative to the ground plane, °.

3.21

safety concept

measures taken in allusion to system integrity during system (e.g., electronic unit) design to ensure safe operation in case of circuit failure, covering the condition of maintaining part of the work or providing backup systems for important machine functions

4 Accuracy of instruments

The accuracy of the testing instruments shall meet the requirements of GB/T 21153-2007.

According to the provisions of GB/T 21153-2007, the average of 3 measured values shall be taken as parameters which are not otherwise specified, and the measuring accuracy shall be as specified in Table 1.

5 General requirements

5.1 General provisions

5.1.1 The requirements of this clause apply to all of the machines covered within the scope of this standard.

5.1.2 Unless the hydraulic medium which can cause the brake to be applied in case of pressure-relief can be released when the driver is no longer in contact with the brake control, the device that maintains the brake applied via hydraulic pressure shall not be installed in any brake system.

5.1.3 The environmental pollution and impact of all brake systems that are designed, manufactured and installed shall be minimized.

Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Accuracy of instruments
5 General requirements
5.1 General provisions
5.2 Requirements for the brake system
5.3 Common component
5.4 Brake control
5.5 Service brake system
5.6 Holding performance
5.7 Secondary brake system
5.8 Parking brake system
5.9 Hydrostatic brake system
5.10 Accumulator performance and alarm device
5.11 Brake system with electronic machine control system (MCS)
5.12 Machines designed for drawbar trailers
5.13 Machine specification and labels
6 Test conditions
6.1 General parameter test
6.2 General test conditions
6.3 Test course
6.4 Configuration for machine test
7 Performance test
7.1 General requirements
7.2 Control of brake system
7.3 Accumulator
7.4 Holding performance test
7.5 Break performance
7.6 Alternative auxiliary brake tests for hydrostatic or similar driving machines
8 Test report