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SB250 hydraulic failure protection brake Product manuals
- Jun 06, 2018 -



SB250 hydraulic failure protection brake(Hereinafter referred to SB250) are mainly used as service or emergency brake for various large and middle crane and port handing machinery at hoist and low speed shaft of pitching mechanism ,service of emergency brake for mine winder and lifter and service as emergency brake for cable car and ropeway cranes at drive system.

SB250,disc spring is applied to closed and hydraulic released,the structure as shown in Figure 1,composed of two identical halves.It works as below:When the hydraulic control system command standing next to the brake cylinder pressure oil supply, pushing outward movement of the piston and further compressed disc spring, disc brake shoes from the brake rod traction under braking torque elimination; standing when the hydraulic system Under the command turned back to the oil passage, hydraulic pressure oil tank under reflux disc spring force, the piston and rod to the brake disc side motion, disc spring force is transmitted through the brake shoes to the brake disc, the system generates required Moment.


2. Technical parameters 



Space for each side

Rated brake force(kN)

Switching off pressure



Install bolt\tightening torque






6-M39 12.9level 5000Nm









1、Assembly fastening bolt   2locknut  3locknut   4indicator cock  5eye bolt  6exhaustmanometry connect         7platen  8brake disk  9brake backing strap  10foundation bed  11Piston  12belleville spring   13adjustment lever  14rear cover      15support

3.1Hoisting and transport

Brakes should be properly lifting, to prevent damage, use cranes and lifting slings, sling position shown in figure 

2. Do not use parts other than the rings, nuts transported.


3.2 Preparation before installation

3.2.1The check of the brake and the disc

aAll parts of brake is complete or not

bwhether it have the oil,paint and other impurities which will effect the friction force of the Liner friction surface.

cCheck the model is suitable for the requirements.

dThe surface of the brake disc shall not have rust, oil, electric welding defects such as scars, uneven, Cracks or other serious defects that have occurred prohibited the use of the brake disc


If any of the above content does not meet the requirements, must be resolved before installation.


3.2.2The inspection and installation of the brake bracket and base

aThe bracket of the brakeSee figure 1:15Generally not supplied (user orders excluded), the user must make their own mounting bracket

bThe mounting base of the brake should be stable and The mounting base brake should be stable.

cIf the installation of the base together with the brake,should be fixed after the initial installation of the brake position accuracy(welded or bolted connect)

dIf the brake mounting base is also not processing installation hole, should be in place right after the brake installation. Drilling holes, then fixed brake.


The dimensions, tolerances, surface roughness requirements of the Brake mounting bracket and the brake disc shown in Figure 3 



Note: E is the thickness of the brake disc



3.3.1Mounted the brake on the brake bracket


If the user supply the mounting brackets and fastening bolts when place the orders,  factory will supply the installed bracket and brake caliper  together with the goods, this work can be omitted

a、 Remove oil and dirt clamps and mounting bracket with the surface, with crane lifted the brake caliper on the bracket
Note:Exhaust connector (Figure 1 : 6) side must face upwards

b、 Brake calipers with six high strength bolts fastening nut strength 12.9, with nylon lock inserts, flat pad of 45 steel, quenched HRC35 ~ 45.

You must use a torque wrench to tighten the bolts, tightening torques in Table 1

3.3.2 The hydraulic connection and the brake cylinder exhaust


aInstalled before the first hydraulic brake good installation (installation and commissioning of hydraulic station hydraulic station reference manual), line up the hydraulic lines, Brake cylinder inlet connector is M18X1.5, hydraulic pipe diameter requirements of more than 10mm.

Must ensure that all brake cylinder to hydraulic piping length equal

bBefore using and adjusting brakes, brake cylinders to exhaust, the method is: the highest point in the brake cylinder (top) has a manometry and dual exhaust joints (Figure 1 piece 6), thread size of M16, Remove the protective cap when manometry, the components can be connected manometry; exhaust collar when the anti-down protective cap on the win, then tighten the cap can be specifically shown in Figure IV, After the exhaust to restore it.


3.3.3The installation of the brake

a、The hydraulic brake lines turned cylinders, hydraulic station open open brake, brake caliper after the sides and the back cover and tighten the lock nut (Figure 1 :2 and 14), the brake to keep floodgates state, Then disconnect the connection pipe (usually at the factory, with the cover and tighten the lock nut).


bFigure 2 shows the mounting base on the brake assembly hanging screwed on the bolt, and loosely put the nuts and washers.

cAdjust the position of the brake bracket, and so on in parallel with the brake disc, brake pad edge indented than the outside diameter of the brake disc 3 ~ 5mm (see Figure 1) related tolerances as shown in Figure 3.

dTighten the bolt to flatten until the spring washer, connect the hydraulic lines, hydraulic station pass into the open hydraulic oil, relaxing lock nut from the rear 8mm, and lock nut (Figure 1 piece 3) lock.

Note: The lock nut during normal work must be more than 8mm from the back cover and tighten the lock nut.

eClose hydraulic brake tight gates
    3.4 The adjustment of the brake
    Adjust the brake torque and brake adjustments, including adjustments gate gap, detection switch, mainly during the initial installation and liner wear a certain value, or replacement of the friction pad later be

3.4.1Adjust the distance back

By adjusting both sides of the brake caliper on each side of the gap at the gate to set the brake force adjustment method is as follows:

On the state of the brake brake measurements C (Figure 1).

a.The hydraulic pressure is set to table the required rating, open hydraulic station, open the brake, then C should increase the size of 4mm.

b.If size is not equal to the set value of C increases the braking force on each side of the gap corresponding values must be adjusted. In the floodgates state, with a large 24mm Wrench clockwise adjustment lever (13) back from the narrow, whereas increasing the displacement volume adjustment lever revolution is about 2mm.

c.Close hydraulic station, so the brake closed gates, measuring the value of C, then open the brakes, measuring changes in the amount of C values.

d.Repeatedly adjusted until it meets the requirements.

Note: The brakes on both sides of the withdrawal from the brake cylinder must be adjusted to the same value, otherwise the brake disc axial force.

e.If the actual needs of small power brake modulation, and do not want to increase the gap on each side, you can transfer a small nominal output pressure hydraulic station (with Hydraulic adjustment method body reference manual) to achieve.


3.4.2 Switch adjustment

 Gate can be installed brake pads and brake instructions indicate proximity switch proximity switch (Figure 1: 4), or installed in accordance with user requirements other signal detection switch on the brake caliper halves.



Switch ModelBI5-M18-AZ3X(TURCK)

Detection distance5mm  

PowerAC 20~250V 50/60Hz

Contact capacity:3~400Ma

Wiring diagram shown in Figure 5


Proximity switch adjustment method is as follows: Loosen the two lock nuts on the switch (not all released), the switch can be moved back and forth, using calipers to measure the distance to touch the switch head to switch between the plates, so that it meets the requirements in Table III (Figure I); If you move the switch does not meet the requirements to achieve so far, and finally tighten the lock nut.


The space for each side


Pad wear indicator

Brakes floodgates instructions

Brake closed gate

Brake gates

Brake closed gate

Brake gates

















Note1X  0.5mm corresponding brake pad wear

      2the detects distance of the proximity switch is 5mm


4.Usage and maintenance


4.1.1Pls check below items before usage

a, install the brake is correct and meet the requirements.

b, whether the brake debugging debugging requirements.

c, the surface of the brake disc and brake pad surface is clean and free of oil.

 After checking all the normal, run test can be carried out together.


4.1.2 run test

a ,normal working state without load movement of the brake 10 to 20 times (the main motor and brake disc run together, the same below), if unusual, after excluding re-test until normal.

 b, at 50% of rated load brake 10 to 20 times, whether the observed steady state braking (braking basically the same distance each time), such as braking stability, braking can be 3 to 5 times the rated load.

c, during the test run together, you should always check the following:

1) brake pads and brake discs fit state;

2) brake disc temperature (should not exceed 350 ℃);

3) threaded connection is loose;

4) switch signal is normal;

5) brake, running sound is normal;

6) hydraulic system for leaks.

 After the test run properly, the brake can only be put into use.


4.2 Maintenance

4.2.1 Daily inspection

Brakes every 3 to 7 days should be checked as follows:


1.The brake disc and the brake pad surface was contaminated.

2.Brake disc wear of the surface shall not exceed 1mm, or should replace the brake disc.

3.The wear of the brake pad: when the brake pad is less than the thickness of the grinding sheet 3mm, the brake pad must be replaced.

4. Threaded connection is loose.

5.Hydraulic system for leaks.

6.Limit switches moving off is normal.

If there is a change on each side of the gap. Be put to use, such as abnormal, must stop or re-adjusted to exclude the issue.


4.2.2 replace the brake pads

When the thickness is less than 3mm brake pads must be replaced, as follows (Figure I):

1.Open the hydraulic station, hydraulic oil pass into the open brake, loosen the lock nut, lock nut and tighten the back cover, remove the exhaust valve side To the plate (Figure 1 : 7), screw on the brake pads on a M10 screw, remove the brake pads.

2. Check the new brake pads, whether there is oil and distorted, such as surface dirty and must be cleaned with a clean cloth dipped in xylene.

3.From the Insert new brake pads down to the mounting position, tighten the bolts pressed board. Loosen the lock nut, 8mm from the back cover and tighten the lock nut.

4.Close hydraulic station, the brake closed gates.


Note: The brake pads have a certain weight, careful Shuaidie for serious harm. Ensure the brakes when replacing brake pads to keep gate-like State, and the drive mechanism does not rotate and produce an accident occur.


4.2.3 Replace the disc spring set

In the course of the brake, disc springs found at abnormal or brake clamping force becomes smaller (eg braking distance significantly longer), you must open the brakes on the disc spring check found a broken or disc spring injuries, the entire group must be replaced disc spring, demolition method is as follows (Figure I):

1.Remove the brake pads to release oil, remove the display switch, loosen the lock nut.

2.Remove the rear cover 14 bolts, remove the back cover, and finally the disc spring group removed for inspection. For replacement, use a new disc spring, surface coating Good molybdenum disulfide grease, brake reload base (10), and then in the reverse order to the other components assembled.

3.The other side of the brake caliper according to the above method of removal of the replacement and maintenance. Replace the cylinder seals


Brakes work process, if there is oil leakage, sealing elements must be replaced, removed and replaced as follows: The method according to 4.2.3a and b Remove the cover and disc spring, replace the seal element according to the oil spill site, and finally the brake assembly in reverse order Good.


 Note: Model Specification brake pad, disc spring set and sealing elements, please consult the Company. After replacing the brake pads, disc spring set and sealing elements must be adjusted in accordance with 3.4, 4.1 and then follow the check run together and test run, everything is normal before they can be put to use brakes.