Simulation and experimental study of a new structural rubber seal for the roller-cone bit under high temperature

Abstract

Seal element is an important component of roller-cone bit. In order to improve the sealing performance and service life of roller-cone bit under high temperature, a new seal structure with multi-segment arcs is designed and the structural parameters of this sealing ring are optimized by response surface method and finite element method. Firstly, the hydrogenated nitrile-butadiene rubber is used to improve the seal performance under high temperature, and the uniaxial, planar, and biaxial tensile experiments are carried out to study the constitutive model of this rubber. Then, a three-dimension transient thermo-mechanical coupling model is established. The comparison of sealing performance between the new structural seal and the traditional O-ring seal is implemented under high temperature through the proposed FEM and laboratory experiments. The results show that the new structural seal has lower contact pressure and Mises stress than the standard O-ring seal, and the service life of the former is almost twice of the later one. Additionally, a composite drill bit using the new structural seal is applied to a deep drilling. After servicing a certain time, it shows that the wearing capacity is very small. The results show that the new structure seal ring can adapt to high temperature environment and the optimization method is feasible.

Micro-Groove Optimisation of High-Speed Inner Ring Micro-Grooved Pumping Seal for New Energy Electric Vehicles

“…As shown in Figure 9, the opening force increases nonlinearly with the rotational velocity, indicating that a higher rotational velocity leads to a stronger hydrodynamic effect on the inverted fir tree-shaped groove with one layer of branches (7) and, thus, a higher opening force. The pumping rate first increased nonlinearly, decreased with rotational velocity, and then gradually stabilised.…”

“…Effects of Rotational Velocity on Performance of Micro-Grooved Pumping Seal Figure 9 shows the computed opening forces and leakage rates at different rotational velocities ranging from 2000 to 80,000 r/min, with other parameters set to the values listed in Tables 1 and 2. As shown in Figure 9, the opening force increases nonlinearly with the rotational velocity, indicating that a higher rotational velocity leads to a stronger hydrodynamic effect on the inverted fir tree-shaped groove with one layer of branches (7) and, thus, a…”

“…Figure 8 shows that the pumping effect of inverted fir tree-shaped grooves is generally good, while rectangular grooves are slightly inferior. Among them, the inverted fir treeshaped groove with one layer of branches (7) has the best pumping effect. The pumping effect of inverted T-shaped grooves (3), semicircular grooves (5), and semicircular ring grooves ( 6) is relatively weak.…”

“…The inverted fir tree-shaped groove with one layer of branches (7) is the optimal among the 17 groove types. This section analyses the effects of rotational speed, oil-air ratio, inlet pressure, and temperature on the sealing performance of this groove type separately.…”

“…The working conditions of traditional fuel vehicle engines and EV power systems are similar. Therefore, rubber skeleton [6,7] and polytetrafluoroethylene (PTFE) [8][9][10] oil seals have been widely employed in electric drivetrain systems. Rubber skeleton seals have a maximum allowable linear speed of approximately 38 m/s but perform poorly under reverse rotation.…”