Design and Braking Stability Analysis of a Novel Internal Pump-Hydraulic Retarder Axle for Heavy Articulated Vehicle

The retarder is widely used to ensure braking safety in heavy vehicles due to its noncontact braking characteristics. Currently, retarders are generally mounted on tractors, but semi-trailers have greater inertia and are prone to accidents. Therefore, the semi-trailer’s brakes have to work frequently to maintain stability during downhill braking, which causes the brakes to generate high temperatures or even failure. Based on the above problems, a novel internal pump-hydraulic retarder axle (IP-HRA) is proposed, which integrates the pump and hydraulic retarder (HR) into the support axle. The prototype of the IP-HRA was made and a bench test was conducted. In the experiment, the single-side braking power of the IP-HRA reaches 300 kW and its torque can be controlled by adjusting the outlet pressure. A co-simulation model of articulated vehicles is established to predict the braking state by computer solutions. Based on the experimental data, the methods of IP-HRA braking semi-trailer and traditional HR braking tractor are compared. The results of co-simulation show that the IP-HRA is more conducive to the braking stability of the articulated vehicle than the traditional HR when only retarder is used. Finally, the braking time and braking deceleration of IP-HRA are verified by road experiments.