Automobile brake wandering how to solve the maintenance
发布日期:2015-08-26 16:38:00 Number of clicks:
So-called automobile brake running deviation, that is, the wheel brake, plays a role of brake on both sides of the wheel not at the same time. Even while the wheel brake, but on the other side is still turning, cause the cars can't park along the straight line direction. This is caused by uneven coaxial around on the wheel braking torque, and the rotation of the steering wheel has obvious driver, car toward one side of the road.
Brake wandering
Automobile brake system is the key part of automobile safety, the stand or fall of its technical conditions, directly affects the driving safety, therefore requires absolute normal brake system work while moving. Normal braking performance is good, except one feet sensitive and effective; When emergency braking, four LunTuo not too long, no more running deviation occurs. Car in everyday use, are often faced with brake system failure, especially the braking snaking phenomenon, if not promptly eliminate, will seriously affect the safety; Especially in mountain driving braking, even greater risk. Let's have a look at the causes of brake wandering what.
The causes of brake running deviation
Automobile brake system plays a very important role in the brake, so we are looking for brake reason of should get up from the braking system first.
Brake running deviation caused by friction pair
All of the automobile brake systems use friction brake. The wheel brake using the friction brake wheel, tire and ground friction car parking, shows the importance of friction to the brake system. On both sides of the brake disc and drum brake friction coefficient inconsistencies, such as smooth and rough, rough side smooth side of the brake disc, make both sides braking and produce brake running deviation.
Brake running deviation caused by friction pair
Brake causes of brake running deviation
Disc brake during braking, brake fluid offshoring moves the pistons, piston driven aim was to brake disc brake block and brake. Piston when offshoring to overcome certain resistance (i.e., start-up pressure), if the resistance is not the same size, which will affect the brake block effect in time and force, the size of the brake disc brake running deviation.
(1) a brake chamber diaphragm rupture or brake pump seal damage, fuel oil, air and brake pipe or tubing.
(2) putting a brake chamber deformation or jammed or brake wheel cylinder piston to bite. (3) a brake CAM shaft rust, action is not flexible, damage of regulator.
(4) brake shoe of the underwriting rust bite. About 5 brake shoe and gap size.
About 6 different brake lining materials, different thickness, friction coefficient, etc.
7 a brake friction disc such as oil.
Brake causes of brake running deviation
Return spring failure braking brake running deviation caused by difference is very big
Drum brake during braking must first overcome the brake shoe return spring tension (that is, the threshold pressure), and then make the friction brake shoe and brake drum brake torque is produced. If the drum brake design of return spring force requirements is not very tall or return spring card dead, so overcome when braking brake shoe return spring force is not the same, left and right brake braking force produced by the different size and speed, resulting in a braking snaking phenomenon.
(1) the return spring tension about brake sizes.
(2) brake chamber about push rod lengths.
(3) individual worn brake drum circle or lost.
(4) individual wheel of the CAM shaft lining and shoe underwriting kuang, etc
Return spring failure braking brake running deviation caused by difference is very big
Brake master cylinder causes of brake running deviation
Brake master cylinder is used to transfer the pressure of the driver step on the brake pedal in the four wheel brakes to make the car stop. According to the requirements of the traffic laws, hyundai motor vehicle braking system must adopt double circuit brake system, so the hydraulic brake system has adopted tandem double cavity type brake master cylinder. Two cavity when the brake master cylinder is built pressure differential pressure or speed is not at the same time, the effect of different hydraulic pressure on the brake. Different result in different braking force, braking pressure that cause brake running deviation.
Brake master cylinder causes of brake running deviation
Proportional valve failure caused by the brake running deviation
Automobile brake before and after the role of the proportional valve is to adjust the brake hydraulic pressure distribution, the size of the rear wheel when the car in the brake is not easy to produce lock, prevent the sideslip. The car with a proportional valve, pressure differential pressure was adjusted by proportional valve, the effect on the left and right brake pressure is different, that cause brake running deviation.
Proportional valve failure caused by the brake running deviation
Brake pipe plug braking wandering
Side brake GuanAo a foreign body or flat plug, make the air intake (or feed) cross section changes, intake (oil) resistance is big, pressure is relatively slow; About other brake pipe length different braking time needed for different, can cause different braking
Step phenomenon; With hydraulic brake pump or pipe into the air, my cup, work failure and wandering.
Brake running deviation
Failure caused by braking wandering
Disc brake piston return bad, lead to brake braking jammed and wandering. As unilateral drag caused by hysteresis torque of brake running deviation.
Drum brake wheel cylinder (points) pump leak or a side of the pump piston hairpin, hair acerbity brake running deviation caused by.
System for leaks, joint can make both sides brake effect caused by the inconsistent brake running deviation.
There is air braking system, especially close to one side of the brake pipe with air will make the brake effect is not consistent, both sides and produce brake running deviation.
Left and right wheel brake friction is different
(1) friction lining origin, different material, different thickness, contact area. Different materials of products are different
Thermal performance decline, in the case of frequent brake, friction lining of poor material performance deteriorated.
(2) brake drum grinding loss, especially around the drum diameter limit, the drum deformation and facing poor contact.
(3) the individual wheel or friction lining with stained with oil, hardening, rivet, on both sides of the range of braking torque; Shoe of the underwriting and seat covers, brake CAM shaft wear and tear strength that card; Shoe return spring elastic vary too much, when braking led to open the shoe out of sync.
(4) brake main components processing precision is low, assembly improper adjustment.
(5) the backing plate occurred plastic deformation; Cylinder spring corrosion failure; Individual cylinder push rod bending deformation, diaphragm CAM binding or being damaged.
(6) oil pump series, pipe fittings and leakage, will change the brake technical performance at any time, make it produce brake friction from time to time change.
About brake shoe and brake drum clearance is different
About the brake shoe and brake drum clearance is different, lead to braking time, big gap when one side of the brake response slow; On one side of the small gap when braking reaction quickly.
About brake shoe and gap size can also cause braking snaking phenomenon.
In addition to the above causes of brake running deviation and screening car other possible factors system, some brake running deviation caused by failure is not necessarily the automobile braking system.
The friction between the tire and ground factors about tyre technology condition and wandering
On both sides of the brake pads (butterfly brake) or the brake shoe (drum brake) using a different brand of different specifications, the friction effect is different, on both sides of the braking force, resulting in brake running deviation phenomenon.
Automobile brake to achieve, not only need to have enough braking force, and need enough adhesion coefficient between the tire and ground, if the tire pressure, decorative pattern, wear on the coaxial degree of inconsistency, the adhesion coefficient of the tire is different, can cause brake running deviation. And the same shaft do not match the tire size (diameter size is not equal to), resulting in left and right wheel braking force is not equal, will cause brake running deviation. Can be found in the process of road test, is also caused by tire braking wandering without rules, when the left the right. About tire technology condition is different, both sides decorative pattern, uneven abrasion degree and the air pressure, about tyre diameter difference is too big, etc., all can cause irregular brake wandering.
On both sides of the center of mass migration result in uneven wheel braking and wandering
Due to the loose fasteners, the leaf spring after displacement, cannot maintain a normal line stop the wheel; Before the leaf spring, uneven stretch of cause load migration; Spring steel frame deformation, front and rear shafts of u-shaped bolt looseness, spring steel plate bolt broken center shift between front axle and may cause variation (left and right wheel base), in a straight line of cars are running deviation occurs when driving and braking. High vehicle overloading, emergency brake at high speed, on both sides of the wheel brake uneven due to the center of mass migration and wandering.
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Frame deformation cause brake running deviation
Range around wheelbase, wheel alignment misalignment, frame, or front axle deformation, such as when the vehicle braking, mutual interference (or uncoordinated) also produces brake running deviation.
Braking torque range cause brake running deviation
Car loaded unevenly, centroid position about asymmetry, obvious to one side, on both sides of the brake torque, braking snaking phenomenon will occur.
When braking on the left and right wheel braking force are equal in size, brake force growth speed of uniform load under the condition of small wheel will lock first, and the load bearing after the big wheels because of inertia effect must lock, so, the phenomenon of the brake wandering. This kind of phenomenon under the condition of the loaded car will be more apparent, no-load conditions generally will not happen. On the brake inspection and no obvious reaction. Caused the main reason is: the frame deformation; Shock damage; Leaf spring deformation, fracture and fatigue; The suspension system of the guide bar or balance beam deformation, etc. Car, of course, in the process of loading, artificially uneven stacking, the goods will also cause the vehicle wheel load distribution caused by braking wandering around.
Four-wheel location is not correct
Wheel alignment is not correct will cause automatic steering wheel "place", "wandering", the phenomenon such as abnormal tyre wear, destroyed the stability of the car, will also cause a brake running deviation during braking. Mainly before running deviation when braking. Braking can be found in the process of road test in the direction of running deviation is not fixed, but when the left the right. And there is no obvious reaction on the brake test. Caused the main reason is: frame deformation, damage to the suspension system, deformation, deformation of the front axle and steering knuckle kuang and toe improper adjustment, etc. It is worth mentioning that the vehicle in the case of serious overloading, the frame deformation, great changes have taken place, the radian of spring steel will also cause a wheel alignment is not correct, cause brake running deviation. Should this phenomenon has caused the great attention of the driver, lest cause safety accidents.
Roads lead to brake wandering
Braking requirements when the wheel and the road and should have enough adhesion coefficient, because the road was muddy, convex-concave, deflection, the automobile brake braking will also appear when wandering, this requests us in the road test must be in a flat, dry, clean and high adhesion coefficient of cement or asphalt, to eliminate factors on the impact of the automobile brake wandering road.
Running deviation and sideslip are connected, can cause serious wandering back axle side sliding, easy to skid car also has a tendency to sharpen the car running deviation.
Brake running deviation fault diagnosis approach
For automobile brake system as a whole
1) check if it is found that the brake pump seal damage, brake pipe or tubing leakage, leakage, replacement should be given.
2) for the brake wheel cylinder piston bite. A wheel cylinder piston should be replaced.
3) about brake wear ranging. To give change
4) different brake lining materials and different thickness, friction coefficient, etc. Should be replaced to adjust.
5) check the brake lining such as oil. Should give clear.
Maintenance of brake wandering
1. The vehicle braking on-site inspection of general first, take the road test, according to the tire weight and drag seal length, find out the wheel of the braking effect is poor; And then with reference to the braking effect bad diagnostic procedures to be maintenance.
2. Driving in the car when emergency braking to the road side, the other side of the brake block.
Parking around after got out to examine the wheels on the ground pressure imprinting, drag printed short side for the brake block (if roughly the same length of the two former LunTuo distance and the weight of molecular imprinting, and two rear wheels, on the other hand, shows a spin). In this phenomenon, must look ineffective wheel without leakage, cylinder push rod telescopic situation (skewed, hysteresis and loose card, etc.); From observation hole examined the brake drum, friction between the presence of oil pollution, fit clearance is normal, necessary adjustments according to the rules.
3. Find individual wheel failure, one foot on the brake pedal; Pay attention to the other people see the wheel pump (air brake), trachea, or joint air escaping. If the pump has a flat, as diaphragm broken, tracheal loose connection; No leakage, pump rod telescopic observation points, whether there is skewed, sticking and sealing off.
From brake drum axle of 4, will be set up, and check whether there is any oil on internal hole observation; Check whether the lining is loose; Test on both sides of the wheel friction disc and drum gap is normal. Overhaul again if the situation is good, whether the brake drum circle, friction piece ever wear thin hardening, rivet whether the leakage, etc.
5, check around the front wheel tire pressure or abrasion are consistent; About the steel plate spring force is equal, do you have any obvious displacement, etc. If any should be stipulated in the technical repair.
6, if necessary by reducing running wide on one side of the front wheel brake clearance (or increase the other side clearance) methods to eliminate.
7. If the tyre tow basic requirements, but still wandering, failure is not necessarily in the brake system, check the frame front axle and related parts of the technical conditions; If wheel alignment parameters is not in conformity with the provisions should be adjusted, if necessary, repair and replacement of new parts.
8) detection front suspension parts rod, ball head, hem, arm, or so before the shock absorber, wheel bearings and beam and other parts are correct, and then check whether the left and right sides of the wheelbase is up to the standard.
After more than 9) are qualified, in four-wheel positioning. Road test again to confirm whether brake run partial failure has been ruled out.
Automotive brake running deviation is a common fault, the cause of it a lot, there are many influencing factors. When braking snaking phenomenon analysis, from easy to difficult to troubleshoot, in order to improve the work efficiency, reduce unnecessary trouble.