Industrial brakes are the core components that ensure the safe start stop and precise positioning of industrial equipment, such as lifting machinery, machine tools, conveyor systems, wind power equipment, etc. The selection of appropriate brakes directly affects the operational efficiency, safety factor, and service life of the equipment. The selection should revolve around the three core elements of "working condition adaptation, precise parameters, and risk avoidance", combined with the comprehensive judgment of equipment load characteristics, operating requirements, and environmental conditions. The following provides detailed explanations from four aspects: selection prerequisites, core parameters, scenario adaptation, and pit avoidance points.
一,Three prerequisites that must be clarified before selecting a model
Before determining the type of brake, it is necessary to first sort out the basic operating conditions of the equipment to avoid parameter mismatch or functional redundancy:
1. Clarify the core requirements of the equipment
-Functional requirements: Distinguish between "stop braking" (such as rapid shutdown of machine tool spindle), "parking braking" (such as suspension of crane load), and "speed control braking" (such as tension control of slitting machine). Stop braking focuses on response speed (less than 0.5s or less than 1s, depending on equipment accuracy), parking braking focuses on "failure protection" (automatic locking after power/gas interruption), and speed control braking focuses on adjustable braking force.
-Operating intensity: Determine whether the equipment is "frequently started and stopped" (such as AGV carts and sorting machines, with daily braking>500 times) or "intermittently braked" (such as bridge cranes, with daily braking<100 times). When starting and stopping frequently, special attention should be paid to brake heat dissipation and wear life.
2. Verify the key characteristics of the load
-Load type: Distinguish between "inertial loads" (such as high-speed rotating motor rotors, flywheels) and "potential loads" (such as crane lifting, inclined conveyor belt materials). The potential load needs to calculate an additional "anti fall torque" to avoid the load sliding down after shutdown; Inertial loads need to consider the impact of rotational inertia on braking stability.
-Load fluctuation: Confirm whether the load is a "constant load" (such as a cardboard box being transported at a constant speed) or an "impact load" (such as the moment of stamping by a press machine or the moment of lifting by a crane). The impact load should be added with a safety factor of 1.3-2.0 times (the upper limit for heavy load impact and the lower limit for light load) to prevent failure due to excessive impact force during braking.
3. Evaluate environmental adaptation requirements
-Conventional environment (temperature -10 ℃~60 ℃, no dust/corrosion/explosion-proof requirements): Optional ordinary open brake, no special protection required;
-Adverse environment:
•High temperature environment (such as metallurgical workshop, drying line, temperature>60 ℃): High temperature resistant friction plates (ceramic based, metal based, temperature>300 ℃) should be selected, combined with heat dissipation structures (ventilation holes, water cooling sleeves);
•Wet/dusty environment (such as mines, food cleaning areas): IP65 or above sealing level should be selected, and disc brakes should be preferred for dusty environments (the friction surface is easy to clean to avoid drum dust accumulation and sticking);
•Explosion proof environment (such as chemical workshops and underground coal mines): It is necessary to choose brakes with Ex certification (such as Ex d IIC T4 explosion-proof type) to prevent the danger caused by friction sparks or electrical sparks.
二,Selection core parameter calculation: 4 mandatory indicators
Parameters are the "quantitative basis" for selection, and should be calculated based on the actual operating conditions of the equipment. "Customized parameters" cannot be directly applied:
1. Braking torque (M): the core determining whether it can be stopped or not
-Calculation formula: \ (M=K \ times \ frac {J \ times n} {9550 \ times t_b} \)
Among them: (K) is the safety factor (stopping brake 1.2-1.5, parking brake 1.5-2.0)\ (J) is the total moment of inertia (kg · m ², including the rotating components of the equipment and the load)\ (n) is the pre braking speed (r/min)\ (t_b \) is the required braking time (s).
-Example: The motor speed of a certain conveyor belt is 1450r/min, with a total moment of inertia of 0.6kg · m ². It is required to stop within 4 seconds. Taking a safety factor of 1.3, the braking torque is approximately 0.037kN · m=37N · m (M=1.3 \ times \ frac {0.6 \ times 1450} {9550 \ times 4}), and a customized brake with a torque of ≥ 37N · m needs to be selected.
2. Braking frequency (f): determines whether it can be used for a long time
Refers to the number of braking times per unit time (times/min), frequent braking (f>15 times/min) will cause the friction plate to heat up, and the heat dissipation power needs to be calculated: \ (P=\ frac {2 \ pi \ times M \ times n \ times f} {60 \ times 1000 \ times 60} \) (unit: kW). If the calculated power exceeds the rated cooling power of the brake, it is necessary to install a cooling fan or water cooling device to avoid overheating and failure.
3. Installing adaptation parameters: determining whether it can be installed
-Shaft diameter matching: The inner hole of the brake should be fully compatible with the diameter of the equipment brake shaft (such as a 25mm shaft diameter, choose a brake with an inner hole of 25mm), with a deviation of ≤ 0.05mm, to prevent vibration caused by eccentricity after installation;
-Space limitation: Confirm the reserved space for the axial (brake length) and radial (brake outer diameter) directions of the equipment. For example, a "thin electromagnetic brake" (axial length<40mm) should be selected at the rear end of the servo motor to avoid interference with other components.
4. Static braking torque (M static): Exclusive parameter for parking brake
For potential load devices such as cranes and inclined conveyor belts, static braking torque should be used to counteract the weight of the load when parking, and it is necessary to meet the requirement of M static ≥ 1.2 times the potential load torque, rather than relying solely on dynamic braking torque, to prevent the load from sliding after power failure.
三,Scenario selection plan: adaptation to 8 typical industrial scenarios
There are significant differences in the operating conditions of different industrial equipment, and precise matching is required based on the technical advantages of brake types. The following are selection suggestions for 8 typical scenarios in common industrial fields:
| Application scenarios | Representative equipment | core demand | Recommended brake type | Selection Details Tips |
| Hoisting Machinery | Bridge crane, tower crane, electric hoist |
Power failure self braking, impact resistance, dual safety guarantee |
Hydraulic drum brake (block brake), electromagnetic caliper disc brake | 1. The lifting mechanism must be equipped with "dual brakes" (main brake+safety brake), with a safety braking torque of ≥ 1.2 times the main brake; 2. Outdoor equipment should be selected for rain and dust prevention, and friction plates should be made of wear-resistant materials (with a lifespan of more than 15000 times) |
| Machine Tool | CNC lathes, machining centers, grinders | Accurate positioning (deviation<0.05mm), fast response (<0.1s) | Electromagnetic power-off brake (DC24V), servo brake | 1. Select the "high-speed brake" for high-speed spindles (speed>3000r/min) to avoid damage to components caused by centrifugal force; 2. When positioning requirements are high, choose the "zero backlash structure" to prevent reverse movement from affecting machining accuracy |
| Belt Conveyor | Mining conveyor belt, food grade conveyor line | Slow braking (preventing material slipping), dust resistance/cleaning | Hydraulic push rod brake, pneumatic disc brake | 1. The inclined conveyor belt (angle>10 °) needs to be equipped with a "backstop" to avoid reversing after stopping the machine; 2. The food industry chooses stainless steel shells and food grade lubricants to eliminate the risk of contamination |
| Logistics Sorting | AGV car, sorting machine, drum line | Lightweight (weight<2kg), frequent start stop (>20 times/min) | Micro electromagnetic brake, permanent magnet brake | 1. Select the "low-power type" (standby current<8mA) for AGV brakes to extend battery life; 2. Prioritize the "wet friction structure" for frequent start stop operations to reduce wear and extend lifespan |
| Metal Forming | Stamping machine, bending machine, rolling mill | Large braking force (>1000N · m), high temperature resistance (>150 ℃) | Hydraulic disc brake, pneumatic drum brake (pneumatic block brake) | 1. Choose the "quick response type" (braking time<0.2s) for the stamping machine to avoid punch overshoot; 2. The brake for the rolling mill needs to be equipped with a water-cooled jacket to ensure that the heat dissipation power is ≥ 10kW |
| Wind Power Equipment | Wind turbine (main shaft, yaw system) | Low temperature resistance (-40 ℃), high reliability (lifespan>100000 cycles) | Hydraulic caliper disc brake, mechanical locking brake | 1. The spindle brake is equipped with a "manual release device" for easy maintenance; 2. Select "normally closed" yaw brake, maintain positioning after power failure, power consumption<5W |
| Textile Printing | Textile machines, printing machines, slitting machines | Constant tension control (accuracy ± 5%), smooth braking | Magnetic powder brake, magnetic powder clutch | 1. Tension control requires adjusting the braking force through current to ensure stable tension; 2. Avoid humid environments, as magnetic powder is prone to clumping and failure due to moisture. Proper moisture-proof protection is necessary |
|
Construction Machinery |
Concrete mixing plant, construction elevator | Dust resistant, vibration resistant, high load resistant | Pneumatic drum brake, hydraulic caliper disc brake | 1. Select the "anti sticking type" brake for the mixing plant to avoid cement dust agglomeration and blockage; 2. Construction elevators must comply with the GB 26557 standard and be equipped with dual safety brakes |
四,Selection avoidance: 5 common errors and correction methods
1. Error 1: Only select based on "motor power", ignoring the moment of inertia
-Consequence: If the motor power is the same but the load has a large moment of inertia (such as equipment with a large flywheel), it can lead to excessive braking time or even ineffective braking;
-Correction: It is necessary to calculate the "total moment of inertia". For equipment with a large moment of inertia, a brake with a larger braking torque should be selected instead of simply matching the motor power.
2. Error 2: Using ordinary resin based friction pads in high-temperature environments
-Consequence: Ordinary resin based friction pads will carbonize at temperatures greater than 120 ℃, causing a decrease in braking force of over 50%, and in severe cases, leading to brake failure;
-Correction: For high temperature scenarios (>100 ℃), choose ceramic based (temperature resistant to 600 ℃) or metal based (temperature resistant to 400 ℃) friction pads with heat dissipation structures.
3. Error 3: Choosing drum brakes for dusty environments
-Consequence: The gap between the brake drum and the shoe of the drum brake is prone to dust accumulation, leading to jamming or uneven braking force, which affects braking stability;
-Correction: In dusty environments, disc brakes (with exposed friction surfaces, easy to clean) should be preferred, or drum brakes with fully sealed dust covers should be selected.
4. Error 4: Parking brake only looks at "dynamic braking torque"
-Consequence: The dynamic braking torque meets the stopping requirement, but the static braking torque is insufficient. When parking, the load gravity is greater than the static torque, resulting in equipment sliding (such as a crane falling from a suspended load);
-Correction: The "static braking torque" should be separately calculated for the parking brake to ensure that it is ≥ 1.2 times the potential load torque, and the "normally closed failure protection brake" should be prioritized.
5. Error 5: Ignoring the need for "brake clearance adjustment"
-Consequence: After the friction plate wears out, the clearance increases and the braking force gradually decreases. Failure to adjust in a timely manner can lead to brake failure and increase maintenance costs;
-Correction: In frequent braking scenarios (such as AGVs and sorting machines), selecting "automatic gap adjustment brake" eliminates the need for frequent manual maintenance and reduces operation and maintenance costs.
五,Summary of selection process: 4 steps to quickly implement
1. Requirement disassembly: Clarify equipment functions (stop/park/speed regulation), load types (inertia/potential energy), and environmental conditions (conventional/harsh);
2. Parameter calculation: Calculate braking torque (including safety factor), braking frequency (including heat dissipation), installation dimensions (shaft diameter/space), and static braking torque (parking scenario);
3. Type matching: Match according to the scene, exclude brake types that do not meet the environment/function requirements, and narrow down the selection range;
4. On site adaptation verification: Conduct a "pre installation test" on the initial brake and equipment to check the accuracy of the shaft diameter fit (measured with a micrometer for clearance), spatial interference (whether other components are rubbed during simulated operation), and conduct 10-20 actual brake tests to verify whether the braking time and smoothness meet the requirements, ensuring that the actual operating effect is consistent with the theoretical calculation.
Through the above process, precise selection of industrial brakes can be achieved, which not only meets the requirements of safe operation of equipment, but also balances economy and service life, avoiding production interruptions or safety accidents caused by improper selection.