During the working process of the jaw crusher, the rotary of cam gear drives the plunger type injection pump to supply high pressure oil to the system. The oil pressure of the system will be determined by the rating nut of the oil pressure adjusting gear according the biggest crushing force allowed for the crusher. When the oil pressure goes up, the plunger compression spring in the oil pressure adjusting gear will shift to the right side, and drive the plunger injection pump plunger to rotate in the anti-clockwise direction, shorten the effective path of the plunger in order to decrease the oil injection amount and restrict the system oil pressure to go higher. On the contrary, when the system oil pressure decreases, increase the oil injection amount in order to prevent the decrease of the system oil pressure so that the oil pressure of the hydraulic system is kept in the original set state.
When the crusher is working normally, the pressure functioned on the working cylinder by the toggle plate of the crusher is smaller than the thrust of the hydraulic cylinder, and the movement calve is in an upper extreme position, and the toggle plate will not move so that the crusher will crush materials normally.
If some uncrushable materials go into the crushing chamber of the jaw crusher, the crushing force will increase. At this time, the pressure functioned on the working cylinder by the toggle plate of the crusher will be higher than the thrust provided by the hydraulic cylinder, and the oil pressure in the high pressure oil chamber will increase in a second, the throttle valve will drive the movement valve to move, and the system will leak oil in order to limit the biggest thrust of the toggle plate in order to protect the machine.
After some uncrushable materials go into the crushing chamber, limited by the biggest thrust provided by the working cylinder, the piston will move to the right side and withdraw, and respectively the ore discharging mouth of the crusher will become bigger. Because of the mesh of the movable jaw of the crusher, the uncrushable materials will gradually move down and finally be discharged from the ore discharging mouth. If the products produced by the uncrushable materials in the crushing chamber are not qualified, then the workers can remove them with auxiliary device.
After the uncrusable materials are removed automatically, the piston is in a withdrawal position. Because of the decrease of the crushing force, the movement valve will drive the spool to move back to the upper extreme position without the instant high pressure of the upper chamber so that it will not leak oil to the system. At the same time, the plunger type injection pump will pump oil to the system with the highest pump oil amount under the effect of the oil pressure adjusting device until the working cylinder piston moves left side to the extreme position. At this time, the crusher will return to the normal working condition.
Compared with the foreign advance level, the design of jaw crusher in our country still has a big gap in the quality and performance. As for the same machine model, the weight of the machine in other countries is lighter than that our country which shows that the comprehensive proficiency of design and manufacturing is much higher than that in our country. In addition, the bearing of the machine is much smaller but has a longer service life.
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