Carter excavators, maintenance and balancing valve and correct selection of two-way hydraulic lock, and an overview of the two-way hydraulic lock and balancing valve on some occasions, can be used as a locking device, can guarantee work device due to external causes such as weight dropped, speeding, or string.
But in some specific speed load cases, but cannot be used interchangeably, below according to the structure of two kinds of products, the author discuss some opinions of.
Two, the structure characteristics of two-way hydraulic lock: two-way hydraulic lock is two hydraulic controlled check valve and used together, usually used in bearing hydraulic cylinder or motor oil, used to prevent the hydraulic cylinder or motor under the effect of weight to fall, need action, all the way to the other oil supply, through oil through internal control oil line open check valve, hydraulic cylinder or motor to action.
Because of the product structure itself, in the process of hydraulic cylinder motion due to the weight of the load, are often working in the main cavity cause instantaneous loss of pressure, vacuum, face the check valve closed, and then continue to fuel supply, makes the work chamber pressure rise and open check valve.
Due to frequently opening and closing action, can make the load on the whereabouts of a larger impact and vibration in the process, therefore, two-way hydraulic lock is usually not recommended for high speed working condition of overloading, and are often used to support for a long time, the speed is not high locking loop of three, the structure characteristics of the balancing valve: balancing valve is also called the speed limit, the lock is a kind of external control in unidirectional sequence valve discharge type, by a one-way valve with a sequence valve and use, in the hydraulic circuit, locking hydraulic cylinder or motor oil in the oil, make the hydraulic cylinder or motor won't due to load falling weight, blocking role at this time.
When the hydraulic cylinder or motor need movement, through to the other oil liquid, at the same time through balancing valve internal oil line control sequence valve open loop connected, realize its movement.
Due to sequence valve itself and the structure of the two-way hydraulic lock, known as at work to establish certain back pressure in the circuit, not because of the weight of the decline in speeding the hydraulic cylinder or motor's main work to produce negative pressure, so you don't happen to the two-way hydraulic lock that shock and vibration.
As a result, the balancing valve commonly used in high-speed overloading, and have certain requirements on the stability of speed loop.
Balancing valve and two-way hydraulic lock structure analysis, the author suggested: in the low speed and light load, on the condition of low speed stability requirement, in order to reduce the cost, can use two-way hydraulic lock used as loop closure, and overloading at high speed, especially for requiring higher speed stability, must adopt balance valve is used as a locking device, must not blindly pursue cost reduction and choose a two-way hydraulic lock, otherwise it will cause a greater loss.
The advantages of the combination of slip-ring seal is mainly the piston structure is compact, and due to the slip ring lubricating material itself, low friction coefficient, hydraulic cylinder for reciprocating motion when very small friction resistance, and can avoid the hydraulic cylinder & other
Crawling & throughout;
And abnormal noise.
Y seal is the most widely used a lip seals, sealing device is a kind of more economic.
The main advantages are low cost and reliable sealing performance.
But the structure of the piston size slightly bigger than the former, the piston seal in the work exists in left and right two lip packing produce between back pressure and seal condition is not stable, and seal back up and move, will happen to seal lip margin or chew the phenomenon such as cutting the root.
To prevent this phenomenon, can adopt the following measures: 1.
Control the slip plane with precision (
Control of the gap between the piston and cylinder inner diameter;
The integral piston.
Control the gap at the same time, gas channel mouth;
The integral piston.
Along the piston ends facing the lip seal grooves parts processing and uniform conducting oil hole, at the same time control the clearance.
In the lip seal grooves and pure rubber bearing ring.
Carter excavator maintenance rotating sealing device is composed of skeleton oil seal and its hole (
Oil seal installation cavity)
And the corresponding dynamic sealing pair of couple (
Its general performance for the oil seal type of outside diameter and hole leakage between the mating surface, and the oil seal lip margin between the rotor and the leakage, and some of the reasons for these two kinds of leakage.
Along the outer diameter of oil seal and a hole between the mating surface has oil seal leakage causes of hole size is too big, rough surface oil seal hole or holes, oil seal caused by improper assembly device malposition and loss of oil seal diameter circle, etc. ;
Along the seal between the sealing lip margin and the axial surface leakage reasons of oil seal lip margin excessive wear or eccentric wear, lip rims have Nick, damage and deformation defects, due to improper assembly lip cock, spring, fall off and labial margin flip, rubber metamorphism cause swelling and hardening, eccentric shaft, rough and defects, etc.