Yj One-Way Shock Absorber

The YJ type one-way Shock absorber (bumper )is a kind of drilling tool. It can effect shock absorbing and shock reduction by means of elastic deforming and anti-coagulation produced from hydraulic oil under the outside force. Its advantages such as simple structure, reliable working performance and easy to maintain can well absorb shocking and vibrating load from drill strings during drilling operation. Therefore, using of shock absorber can raise in structure the service life of drill bit and drill pipe, speed up drilling, get rid of drilling jumping, well protect surface equipments and Drilling Tools.

Working Principle

The hydraulic shock absorber is connected between drill bit and drill collar, the torque is transferred from top Drill String to mandrel. The spline transfers torque to spline outer barrel, oil cylinder and lower sub, then drive drill bit to rotate.

The bit weight is from the which of top drill tool so that drill bit insert drill into formation to break rock into pieces. The drilling mud is fed through bore of drill pipe and drill collar into mandrel of shock absorber, tailpipe, lower sub bore and ejected into bottom well .Because of the uneven bottom well conditions and special structure of cone bit, the drill bit and drill string during drilling operation would produce severe vibration. The hydraulic shock absorber, by means of compressible deformation of compressed liquid under the function of pressure, absorb the energy from drill bit and drill string vibration. Thus, the shock absorber can reduce the vibration and impact load of drill tools.

The SJ type double-ways shock absorbers are used to simultaneously slow down or eliminate the vertical or horizontal shock from drill string. It can reduce the damage due to shocking to drill bit, drilling tool and surface drilling tool so as to enhance drilling speed and reduce drilling cost.

Working Principle

The torsion of bottom hole will be changed with changes in bit structure, formation and bit weight. When the drilling speed reaches up to a certain value, torque and resonance will be happened to drill string. During rotation drilling, the lower part of drilling tool simultaneously bear axially pressure and torque. When bit weight exceed the limit value, the drilling tool will produce a transverse bending (it means lose steadiness) and torque can also make the drilling tool to lose steadiness to be turned into a twist shape. 

Two positions are very typical:

1. The lower bit is suddenly frozen and then torque bumping will be produced unless the cut down rotary energy.

2. Reversing operation in force.

The vertically damping unit is made of mandrel, piston assembly, annular space damping unit and liquid spring of working chamber. Working mechanism: To absorb or release the vibration energy of bit and drill string by means of compressible liquid producing spring deformation in working chamber under the function of pressure. The mandrel moves axially relative to outer barrel when liquid spring is in compression or explanation. Meanwhile, the non-compressible liquid in damping chamber flows through damping space and produces a large number of friction heat so that some vibration and bumping energy are used up. The vertical bumping unit thus can absorb or reduce the drilling tools’ energy in vertical vibration and bumping.

The piston change-over unit is composed of spline outer barrel which is connected with piston by rectangular spline pair and the piston inner hole which is connected with mandrel by ladder-shaped spiral pair. Such a group unit can turn the torque vibration and impact load into vertical component of force in working chamber in a twinkling of an eye so that a constant torque is maintained on.

Product Categories : Downhole Tool > Drilling Jar