Simulation Study On Wheel Ratio Of Single - Cone Drill

Single cone bit is a new bit between three-cone bit and PDC bit. The velocity contrast of cone bit, the proportionality of rotate speed of cone and drill bit, is a key parameter of drill bit which is very important to research the kinematic behavior of bit’s tooth, simultaneously, this is also a indispensable and important parameter in the design of the formal structure of bit’s tooth and many other studies. On the basis of geometry and kinematics of single cone bit, through the gridding technique and the time discretization, the dynamic simulation has been realized gradually beginning with the building of the single discrete point’s simulation model by Matlab. First of all, the geometry model of single cone bit which describes accurately the space geometry structure of the single cone bit’s tooth and the changing regularity of the tooth’s location with drilling time has been set up. Second, the simulation model, the interaction between bit’s tooth which movement is complex and rock, which is used to describe the interaction force while bit’s tooth pushes into the rock and starts to scrape has been built. Then the bottom simulation model which is used to get the relationship of the relative position between the tooth of bit and the rock of the down hole through the spatiallocation of the bit’s tooth and the uneven situation of bottom hole at a certain time has been set up. Combined with the simulation model and overlooked the cone bit’s inertia, the amount and depth which tooth pushes into rock and the reference position of the bit at this time has been confirmed on the condition of static equilibrium. Additionally, the simulation model of the velocity contrast of single cone bit which has confirmed the direction of movement of the cone bit, the force on vertical direction, the torque of eone, the size and direction of lateral force at every discrete time on the basis of the above model, then combined with the model of angular rate, the angular acceleration has been got easily. At last, the simulator of velocity contrast of single cone bit has been worked out.The paper is to obtain the drive ratio by the simulation model which reflects the relationship between those parameters instead of the complex experiment that will need a special instrument. The research results can be used to calculate the drive ratio of the bit, and it has certain reference value to design the new cone bit.