The jaw crusher has a relatively simple structure and is mainly composed of a frame, a working mechanism, a transmission mechanism, an adjusting device, a safety device, and a lubrication system. The following is a brief introduction of the 900mm × 1200mm simple pendulum jaw crusher (Fig. 1).
1. Rack Jaw crusher has two types of integral frame and combined frame. The overall frame is generally welded from castings or steel. Domestic small and medium-sized crushers mostly use integral racks. Rack combination or by a plurality of cast iron fitted with a pin or solder bolt member coupled together, mainly for transportation difficulties (such as underground crusher used) or difficult to manufacture a large jaw crusher.
2. Working mechanism The working mechanism of the jaw crusher (ie the crushing chamber) consists of a fixed weir (ie the front wall of the frame in Figure 1 above) and a moving jaw 5 . The jaws are lined with a lining structure made of manganese steel 2 and 6, the liner is fixed with bolts on the jaws and the wedge. Since it directly participates in the crushing, in order to improve the crushing effect, the surface of the lining plate has longitudinal corrugations, and the irregularities are opposite. At present, the lining of the domestic jaw crusher is mostly triangular or trapezoidal. The surface is vertical and straight. With the application and development of computers, the design of the tooth profile has been developed from traditional test methods and empirical methods into computer-optimized design to achieve the best crushing effect.
Because the wear of the lining is very uneven during the crushing, especially the position of the lower part near the discharge opening is the most serious. For this reason, the lining is generally made up and down symmetrical, and the lower part is worn up and then inverted to extend it. Service life. The lining of a large crusher is made up of many pieces, each of which can be interchanged, and its purpose is to extend its service life.
The crushing cavity shape of the jaw crusher directly affects the technical indexes such as productivity, product particle size composition, particle size, crushing plate service life and power consumption. At present, most of the crushing cavities of the large jaw crushers produced in China adopt the old-fashioned linear all-toothed cavity. This cavity shape has low productivity, high specific energy consumption, easy clogging, large and uneven product size. Recently, a lot of research work has been done on the crushing chamber in China, and a new cavity shape has been applied to production. The two cavity shapes shown in Figures 2a and b have been used in domestic medium and small jaw crushers. Practice has proved that when the swinging stroke and the number of swings are the same, the curved cavity shape has the advantages of high productivity, large crushing ratio, uniform product size, less over-grinding, less wear of the lower end liner of the crushing chamber and lower specific energy consumption. . The advantages of the straight-mixing type crushing chamber shown in Fig. 2c are more apparent. [next]
3. The transmission mechanism is mainly composed of a pulley 10, an eccentric shaft 8, a connecting rod 9 and front and rear thrust plates 12, 13. The eccentric shaft is supported in a main bearing on the side wall of the frame. The upper portion of the connecting rod is mounted at an eccentric position of the eccentric shaft. When the motor drives the eccentric shaft to perform a rotary motion, the link is driven to move up and down due to the eccentricity, thereby driving the thrust plate to move. Since the thrust plate constantly changes its inclination angle during the movement, the rotating eccentric shaft 8 is periodically oscillated to achieve the purpose of crushing the ore. In order to ensure that the moving jaw and the thrust plate are tightly coupled, a tensioning device consisting of two tie rods 15 and two springs 16 is usually used. When the swing is swinging, it not only ensures that the movable jaw and the thrust plate are not separated, but also partially balances the inertial force generated by the movable jaw and the thrust plate.
Since the jaw crusher works periodically, it will inevitably cause periodic changes in the load of the motor, resulting in a very unbalanced load. Therefore, a large crusher generally has one flywheel at each end of the eccentric shaft (one of which is also used as a pulley), and the flywheel of the small and medium-sized crusher can be made one. According to the principle of inertia, the crusher can store energy during non-working strokes and release it during the working stroke, thereby making the motor load even.
4. Adjusting device The lining of the crusher is constantly subject to the wear of the ore during operation, so that the width of the discharge opening gradually becomes larger. In order to ensure the product size requirements, the width of the discharge opening must be adjusted in time. There are three types of discharge opening adjustment devices that are commonly used.
(1) Pad adjustment device. The 17 in Figure 1 above is the pad adjusting device. A set of adjusting pads is placed behind the back thrust plate support. When the number or thickness of the back plates is changed, the rear thrust plates can be moved forward or backward to achieve the purpose of adjusting the width of the discharge opening. The adjustment device is simple and compact in structure, and the weight of the whole machine is not increased much, so large and medium-sized jaw crushers are often used. The disadvantage is that it must be stopped when adjusting.
(2) inclined iron adjustment device. In Figure 3, the inclined irons 6 and 7 are used to adjust the width of the discharge opening. It uses bolts or worm gears or chain drives to lift and raise the rear slanting iron. The front slanting iron is installed in the guide groove on the two side walls of the frame and can only move horizontally. When the rear slanting iron is lifted, the forward slanting iron moves forward along the guide groove due to the inclined relationship, and the thrust plate and the moving cymbal are moved forward, and the width of the discharge opening is also reduced. Conversely, when the rear slanting iron is lowered, the discharge opening width is increased. The advantage of this type of adjustment device is that stepless adjustment is possible and there is no need to stop when adjusting. The disadvantage is that it is very laborious to adjust, and the size of the whole machine is increased, so it is only suitable for medium and small jaw crushers.
[next]
(3) Hydraulic adjustment device. This adjustment device uses a hydraulic cylinder and a plunger to adjust the discharge opening width and supplies oil to the hydraulic cylinder with a manual or electric hydraulic pump. The 900mm × 1200mm hydraulic simple pendulum jaw crusher shown in Figure 4 uses a hydraulic adjustment device. When adjusting, first loosen the nut of the tension spring, open the shut-off valve (normally closed), start the hydraulic pump motor, fill the two horizontal hydraulic cylinders at the rear of the rack, and the plunger pushes the wedge iron forward. When moving to the desired position, close the shutoff valve and adjust the thickness of the gasket. After the adjustment, the shut-off valve is opened, and the oil in the hydraulic cylinder is pressed back to the oil tank by the backward pressure of the crusher, the thrust plate and the connecting rod, and the tension spring is recompressed to a certain position and the shut-off valve is closed.
5. Safety device Because the mechanical parts, iron blocks and other large objects enter the crushing chamber, or the crushing chamber is blocked by materials near the discharge opening, the jaw crusher will be overloaded. At this point, the force on the machine increases sharply. Therefore, a safety device must be provided to prevent accidental damage to the crusher. The commonly used safety devices are as follows.
(1) The thrust plate also serves as a safety device. In the design of the part, the thrust plate is designed to be the weakest link, and when it is overloaded, it is first broken to protect other parts of the device from damage. The thrust plate 13 in the above Figure 1 is not only a connecting rod for transmitting force, but also a safety component of the crusher. The thrust plate is typically made of cast iron and is drilled or slotted in the middle to reduce its cross-sectional area. The thrust plate can also be used in combination (Fig. 5), and the connecting elements such as rivets are made of brittle material, which are first sheared when overloaded. This type of safety device is simple, but the disadvantage is that the handling is complicated and the downtime is long after an accident.
[next]
(2) Overload protection force arm. The JC type jaw crusher (Fig. 7) introduced later, the overload protection is in the form of an overload protection force transmitting arm. The device mainly connects the pulley and the main shaft of the crusher by a leaf spring, and the transmitted torque is realized by adjusting the gasket as needed. When overloaded, the leaf spring is disengaged from the pulley, the pulley idles on the spindle, and the spindle stops rotating, and can be quickly reset when the overload is removed. The device is characterized by no damage to any parts, and the safety of the insurance is high, safe and reliable.
(3) The hydraulic connecting rod is used as a safety device. A hydraulic cylinder and piston are connected to the connecting rod in Figure 4 above. The hydraulic cylinder is connected to the upper part of the connecting rod, and the piston is connected with the lower part of the connecting rod. In normal operation, the hydraulic cylinder is filled with pressurized oil, and the piston and hydraulic cylinder are equivalent to a part of the integral connecting rod. When overloaded, the oil pressure in the lower oil chamber of the hydraulic cylinder increases due to the sharp increase in the pulling force acting on the connecting rod. When the oil pressure exceeds the pressure specified by the high pressure relief valve of the combination valve, the pressure oil is discharged through the high pressure relief valve, and the piston and the thrust plate stop moving, and the movement stops the swing, thereby playing an insurance role. When the overload is removed, the crusher can continue to work after the hydraulic pump motor is started to replenish the oil in the lower cylinder of the connecting rod cylinder.
(4) Hydraulic friction clutch. The 1200mm×1500mm segmental start-up jaw crusher manufactured in China is equipped with hydraulic friction clutches at both ends of its eccentric shaft (Fig. 6). When the crusher is overloaded, the overcurrent relay activates the hydraulic pump motor through the time delay relay to separate the clutch and cut off the main motor, thereby playing an insurance role.
The pulley and flywheel of the crusher are connected to the eccentric shaft by a friction clutch. The friction clutch is controlled by a hydraulic system. When starting, first start the hydraulic pump motor, so that the pressure oil enters the right side of the plunger (ie, the pulley side) or the left side (ie, the flywheel side) through the center hole of the plunger, and pushes the plunger to compress the spring of the friction plate of the friction clutch. The friction plates are separated to disengage the eccentric shaft from the pulley or flywheel. At this time, the motor can be started and the pulley can be rotated. Then, through the electromagnetic reversing valve, the friction clutch between the pulley and the eccentric shaft is first closed, and the eccentric shaft and the connecting rod start to operate. The friction clutch between the eccentric shaft and the flywheel is then closed to rotate the flywheel. The crusher is started in three stages in the above order. [next]
6. The lubrication system is generally small jaw crusher rolling bearing, and medium-sized ships with a jaw crusher with a Pap alloy sliding bearing bush. Usually, the bearing bushes of the main bearing and the connecting rod head are cooled by circulating water when they are overheated. The friction parts of the crusher are lubricated with thin or dry oil. The bearings of the eccentric shaft and the connecting rod head are pressed by the gear hydraulic pump into the thin oil for centralized circulation lubrication. The bearing pads of the movable bearing and the lining seat are periodically lubricated with dry oil by a manual dry oil lubrication gun.
The structure of the compound pendulum jaw crusher (above Figure 3) is similar to the simple pendulum type, except that the connecting rod, the back thrust plate and the moving mandrel are reduced, and the mechanism is simpler. Since the moving trajectory of the moving jaw is not a reciprocating swing centered on the moving mandrel but a complicated trajectory, it is called a compound pendulum type jaw crusher. The movable jaw 11 is directly suspended on the eccentric shaft 10 by a roller bearing, and the lower portion is supported by the thrust plate 5. When the motor drives the eccentric shaft 10 to rotate through the V-belt 13, the dynamic sway is periodically and complexly oscillated to the fixed cymbal. The discharge port clearance of the compound pendulum jaw crusher is adjusted by a diagonal iron adjustment device. Compared with the simple pendulum type jaw crusher, the compound pendulum type jaw crusher has the advantages of simpler and more compact structure; the bearings of the moving jaw and the frame are all adopting rolling bearings, the friction is small, the starting is convenient, and the lubrication is simple; The upper horizontal stroke is larger, which can meet the amount of compression required when the ore is broken, and it has the function of promoting ore discharge when moving downward, so the productivity is about 30% higher than that of the simple pendulum type. Since 1980, the series of compound pendulum jaw crushers has been developed and produced in China.
The disadvantage of the compound pendulum type jaw crusher is that the vertical stroke of the moving jaw is large, which accelerates the wear of the crushing plate, which increases the over-grinding phenomenon of the product, thereby increasing the non-productive energy consumption. In order to overcome the above shortcomings, Beijing Metallurgical Equipment Research Institute succeeded in the development of a new type of energy-saving crusher - JC type jaw crusher based on the digestion of the famous "Kue-Ken" jaw crusher. Figure 7), the device has the following features.
(1) The frictionless crushing mechanism is adopted. During the crushing process, the effect of the jaw on the material is pure pressing force without relative sliding. Therefore, the service life of the raft is 5-10 times higher than that of the compound pendulum jaw crusher.
(2) The crushing cavity adopts the variable tooth angle curve cavity shape, and the full cavity crushing is realized by rationally designing the tooth angle and length of each part of the cavity shape, which improves the passing ability of the crusher and ensures the crushing granularity of the crusher is uniform. .
(3) The use of simple and practical multi-functional mechanical, hydraulic and electrical protection systems. When the crusher is overloaded, the mechanical protection safety clutch quickly disengages the main shaft of the crusher and the pulley, causing the crusher to idle and simultaneously issue an alarm. Once the overload is removed, it can be quickly reset without replacing any parts. In addition, when the crusher is not normal (such as the failure of the lubrication system, damage to the main components, etc.), the multi-function protection system can quickly cut off the power supply, stop the crusher, and issue an alarm. This greatly increases the safety and reliability of the crusher.
(4) The discharge opening adjustment only needs to adjust the front and rear position of the fixed raft without changing the position of the moving raft. Therefore, the adjustment is convenient and time-saving, and the geometry and size of the thrust mechanism are always kept optimal.
(5) The main moving parts of the crusher, such as the front and rear thrust plates, the thrust plate mandrel, the connecting rod eccentric shaft, the bearing and the mandrel are all lubricated with fully enclosed thin oil, and the sealing effect is good. Lubricating oil combines the functions of lubrication and heat dissipation.
(6) The whole machine adopts welded structure, which is light in weight, good in strength, and easy to manufacture and maintain.
