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Hefei Guan Long Valve Manufacturing Co., Ltd.
Contact:Miss Cheng

Address:No. 6, No. 18 Zhongtai science and Technology Park, No. A02, Huayuan Road, Garden Road, Baohe Economic Development Zone, Hefei

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Improvement of Brake Power Valve of Bulldozer

Bulldozers consider it appropriate to use hydraulic assisted follow-up braking. Its restraining principle is that the small valve stem opens or closes the oil inlet of high-pressure oil according to the relative motion position of piston and small valve stem, thus restraining the piston movement. This structure requires that the appropriate precision of small stem 6 and piston 8 is high, and oil leakage is not allowed. There are at least five components required for direct or indirect follow-up control besides the valve body, i.e. piston 8, stem 4, spring 5, small stem 6 and clasp 7. There, valve stem 4 and small stem 6 are complex and require high processing precision. There are many faults in clasp 7, and the unilateral depth of the assembly groove is only 0.45 mm. Because of the influence of processing precision and the corner of the edge of the clasp 7 in the self-made process, the phenomenon of peeling of the clasp 7 has been revealed many times in operation, resulting in the peeling of the small stem 6 by missing the positioning constraints. Finally, the high-pressure oil can not be turned off by driving the stem and the brake is in a constant braking condition. The assembly of the whole device is complicated and trivial.

Because of this, the improved booster valve becomes the structure shown in Figure 2. There are only two components involved in the follow-up control, i.e. piston 3 and stem 1. The working process of Suixing changed into three stages:

(1) The piston movement eliminates the gap between the brake belt and the connecting rod mechanism. The pedal pushes the valve stem 1 to the left by force F. The cone of the valve stem 1 first closes the oil drain opening of the piston 3 cores, which reduces the gap delta. Then, the cover surface of the valve stem 1 is opened to supply pressure oil from the oil inlet to the piston cavity to push the piston to the left.

(2) The piston chamber builds up pressure layer by layer. After the clearance is eliminated, the motion of piston 3 tends to stagnate, and the capacity of piston chamber no longer increases. The oil entering the piston chamber starts to boost. With the further increase of pressure, the valve stem 1 is disconnected from the piston 3, and the oil in the piston chamber leaks out from the core hole of the piston 3 until the amount of oil supplied and released can keep the piston 3 in dynamic equilibrium. Stem 1 controls the opening of the outlet, so it achieves the function of follow-up control. The oil discharged through the clearance () passes through the core hole of the brake piston, and returns to the steering brake valve along the brake linkage pipeline, eventually discharges back to the rear axle box.

(3) When all the energy is put on the pedal, the movement of piston 3 can not be separated from the contact of the valve stem, and the leak of the piston core can not be opened. The pressure of the piston chamber will rise to the pressure of the system. The piston 3 will make the brake belt achieve absolute braking successfully.

In order to reduce the difficulty of technology, the universal valve body 2 of the artificial seat can be improved, the reset spring 2 in the original piston chamber can be eliminated, and 90-deg cone surface can be machined, which is suitable for the valve stem. The main office is to improve the valve stem. In order to avoid the drop problem caused by additional process screw plug and reduce the hidden trouble of failure, the method of drilling core holes, transverse holes and the oil passage through them on the stem is not considered appropriate, but milling grooves on the side of the stem, as shown in Fig. 3.

Because the actual piston stroke with braking effect is small, and in order to prevent the impact of very fast oil filling on the piston, the improved stem inlet is equivalent to & Phi; 2mm groove. Even in the case of tight braking or pedal braking at downhill points, the size of the cut-off plane or surface of the fuel supply line is smaller than that of the main oil line. At the same time, because the transmission force is allowed to decrease when the brake is tightly braked or pedal braked, the effect of this oil spill on the main system is small and will not affect the main transmission oil supply.


Contact:Miss Cheng
Address:No. 6, No. 18 Zhongtai science and Technology Park, No. A02, Huayuan Road, Garden Road, Baohe Economic Development Zone, Hefei
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