Crushing Principle, Gear Wear and Solution of Cone Crusher
The hydraulic cone crusher handles secondary crushing in the production line, and specializes in processing of medium-hard materials. During the operation of the equipment, there will be problems such as tooth cracking, wear, jamming, and undercutting of the umbrella teeth, which will not only affect production, but also Cause direct or indirect economic losses. Through actual cases, this article analyzes the causes and finds out solutions and countermeasures for the problems.
1.Crushing principle of cone crusher
When the crusher works, the motor drives the eccentric sleeve to rotate through the horizontal shaft and a pair of bevel gears. The main shaft of the crusher rotates under the force of the eccentric sleeve, so that the surface of the crushing wall is sometimes close to and away from the surface of the mortar wall, thereby the iron slag is continuously crushed and crushed in the crushing cavity. The working principle of hydraulic cone crusher is shown in the figure below. The hydraulic oil is pressed under the plunger of the hydraulic cylinder, the crushing cone rises, and the slag discharge port shrinks.
2.Hydraulic conical gears are severely worn
Although the hydraulic cone crushing in this case has fewer iron jamming conditions, the phenomenon of wear and tooth cracking is very serious, and even the umbrella teeth are undercut, causing the machine to fail to operate normally.
Before the transformation, the hydraulic cone breaking was frequently repaired and the repair time was long. Generally, it needs to be repaired once every 15 days (the shortest is even half a month), and each inspection is nearly 24h or even longer. When the undercut of the umbrella-shaped tooth is severe, the umbrella-shaped tooth needs to be purchased externally, so the maintenance time is longer.
Due to the uncontrollable condition and maintenance of cone crushing equipment, this has greatly affected the planning and economic indicators of slag iron screening production, and production and sales are often passive.
3. Failure cause analysis
1) Possible cause
The factors that cause the hydraulic cone to break the teeth and cause serious wear are as follows:
① The protective device for cone breaking is not perfect;
② The specifications of the slag iron materials entering the cone crusher exceed the design requirements of the cone crusher (the design requirement is ≤130mm);
③ The specifications of the slag iron material entering the cone crusher meet the design requirements of the cone crusher, but the amount of slag feed is too large (the approved output is 45-120t / h);
④ The iron material entering the cone crusher exceeds the maximum size of the cone crushed iron and is stuck (the maximum iron cross size is 65mm);
⑤ After the cone crusher is stopped, it will be forcibly started with a heavy load;
⑥ The cone crusher does not match the transmission motor (designed motor is 110w, 735r / min).
2) Cause confirmation
After analysis, the reason ⑥ does not exist; the reason ②, the specifications of the iron slag material are controlled by the sieve plate, which is far below 130mm, and both are controlled within 110mm. It is about 30t / h, which is far lower than the approved output of 45-120t / h.
The site observation and summary found that when the cone broke into the iron block, it was not manually released in time and was forced to stop. The slag block material at the cone break slag inlet was piled up. When the slag block material is cleaned, the operator forcibly starts the motor with a heavy load for several times in order to shorten the slag removal time, which causes the cone to break the internal transmission umbrella teeth for multiple overload fatigue and break. In addition, the ability to start the motor forcibly with a heavy load indicates that the protection device is not complete.
4. Implemented measures
At present, in the industry, hydraulic cone crushing, tooth breaking, and abrasion conditions are usually dealt with by: improving the material of the equipment and surfacing hard alloys. According to the principle of cone breaking, as well as the early investigation and research on the causes of equipment failures, combined with the actual situation of the iron slag production line, the following countermeasures are taken to repair and transform.
① The slag conveyed to the cone crusher was originally only a belt head wheel to remove iron; Then a permanent magnet hanging iron removal device was installed on the belt conveyed into the cone crusher slag, and after two iron removals, the slag iron can be effectively avoided Cone is broken.
② Adjust the current of the cone breaking protection device so that it cannot be forcibly started or tripped for instant protection under heavy load.
③ Check the metal content inside the hydraulic oil tank every month.
④ Improve the operation system, strengthen the supervision and assessment of the cone-broken iron, and strengthen the joint responsibility assessment of the person in charge of the production line and the operator.
5. Use effect
After the transformation, the cone crushing equipment runs smoothly, and the surface of the umbrella teeth is basically free of abrasion, which greatly reduces the phenomenon of blockage and seizure. The umbrella teeth have never been undercut and the maintenance cycle has been extended.
1) Reduce the number of daily inspections and maintenance costs
After the transformation is completed, the maintenance period is 90d (up to 150d), and the overhaul of the cone breakage has been synchronized with other equipment on the production line. Each inspection only needs 4-6h, mainly for routine inspection and maintenance such as lubrication, inspection and tightening.
2) Improve the service life of hydraulic cone break
HPY500 hydraulic conical broken umbrella tooth originally had an on-line service life of about 700d. After the improvement, the service life without going offline can be predicted to be at least three years according to the operating effect of nearly one year. After the transformation of the bevel-shaped gear is basically intact, the cone-breaking performance is still good, which fundamentally solves the problem that the bevel-shaped tooth is undercut, thereby greatly reducing the equipment procurement cost.
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