Browse Topic: Rack and pinion steering
Steering system is responsible for providing a precise directional control to the vehicle. The Hydraulic Power Assisted Steering (HPAS) system is commonly used in passenger cars and commercial vehicles due to low cost. Power steering pump develops and delivers required pressure to provide assistance while steering. It reduces the effort required to steer the vehicle. Steering pump (generally vane type) is a critical part providing hydraulic pressure assistance to rack and pinion or gear box. Basically the hydraulic pump noise can be classified as ‘Moan Noise’ and ‘Whine Noise’. The noise generated by power steering pump pressure pulsation is termed as ‘Moan’ and ‘Whine’ based on operational induce frequency. As power train becomes quieter, it becomes more perceivable at typical engine operating speed range and gives impression of poor refinement and quality. This abstract describes the experimental measurement technique to investigate, analyze and quantify the moan noise and elaborate on design of experiments along with its effect on steering system’s moan noise and performance. It also covers the comparative benchmark analysis of different power steering pump designs and its contribution in the moan noise. This research work has helped us to come out with new test method to assess different steering system noises at component, system and vehicle level. Measurements revealed a strong correlation between pump pressure pulsation and steering system moan noise. The subject research work has resulted in elimination of moan noise to achieve better NVH performance in passenger car by optimizing the steering pump and steering line design.
The aerodynamic effects not only directly affect the acceleration and the fuel economy of the race car, but also have a great influence on the handling of the race car. In this paper, the vehicle multibody dynamic model with “double-wishbone suspension” and “rack and pinion steering” is established, in order to obtain aerodynamic parameters, the aerodynamic model of the vehicle is established, and the aerodynamic parameters were calculated by using CFD. In order to obtain the optimal travel track, the track model is established, according to weights allocation of the smallest curvature of each curve and the shortest curve to optimize the optimal route for racing. The influence of aerodynamic effects on the stability of vehicle control is analyzed through simulation of Endurance Racing to evaluate the maximum lateral acceleration、roll angle and other performance. According to the racing speed characteristics and distribution of longitudinal acceleration and lateral acceleration, the racing performance limit is evaluated, Comparing the racing model with the aerodynamic device and the racing model without the aerodynamic device, the aerodynamic device is greatly helpful for improving the single lap speed and helps to increase the maximum lateral acceleration, the car model real-time status is also monitored, thus guiding the racing driver to drive and reducing the lap time.
Rack and pinions are linear actuators that play a critical role in a wide range of linear motion control applications. While rack and pinions are commonly thought of as a timeless technology, several new developments have helped provide significant performance improvements in specific applications. One new approach, the Roller Pinion System, replaces the traditional rack and pinion with bearing-supported rollers, increasing positional accuracy, speed and durability.
Target cascading methodology is applied to the optimization problem of the kinematics of a rack and pinion steering mechanism coupled to a double-wishbone suspension system of a hybrid off-road vehicle. This permits the partition of a complex problem into reduced order sub-problems in a hierarchical manner, leading to a more efficient design and optimization process. According to the nature of the problem, it is proposed a four level hierarchy organization. The uppermost level is the general vehicle design problem. The second level consists in various system-level design problems such as frame, powertrain and the set suspension-steering. The steering system design problem is proposed in a third hierarchical level. At the lowest level are the components design problems. The vehicle under study will work mainly under off-road condition at low speed. Hence, at the steering design problem, two main objectives are searched for optimization: steering performance according to the Ackerman criterion and the steering-suspension coupling effect. Given that these two problems are weakly coupled, it is proposed that each objective is treated as an independent geometric optimization problem, and a coordination strategy is applied in order to guarantee a final consistence of the steering general coupled problem. The proposed methodology is applied to a design scenario and an optimal design solution is found. By this methodology, a complex kinematic problem is decomposed into simpler reduced order sub-problems. This decomposition leads to a more straightforward decision making and optimization in the design process.
Students trained in classic mechanical engineering are taught to construct a system using conventional mechanical components to convert rotary into linear motion. Converting rotary to linear motion can be accomplished by several mechanical means using a rotary motor, rack and pinion, belt and pulley, and other mechanical linkages, which require many components to couple and align. Although these methods can be effective, they each carry certain limitations.
In order to insure that the remanufactured and/or rebuilt steering gear has and maintains the reliability and performance associated with a new OEM steering gear, it is essential that the following procedures be followed; if in-house engineering capabilities are limited, it may be necessary to consult with an outside laboratory to insure all testing methods used meet with the requirements outlined in this paper.
Japanese manufacturers continue to diversify, investing in the launch of a domestic premium brand, updating an iconic sports car, and developing a variety of safer micro cars that are gaining popularity all over the world. Toyota has long been an automotive equivalent of a fine department store. It is the name that carries prestige and trust, inspiring unique merchant and clientele relationships. The Japanese have harbored no qualms about the vastly varying products of the same nameplate, ranging from the small Passo hatchback to a V12-powered executive car. This situation may change soon with the launch of Lexus in Japan-the country's first premium brand-in August 2005, with 140 dealer outlets all adhering to the division's strict architectural, hospitality, and service standards. The division has been operating the Lexus College in the sprawling FISCO premises, the international-standard racetrack Toyota acquired and renovated. The college will have trained a planned total of 18,000 people by the end of 2006, in all facets of the division's operations.
Rack and pinion steering gear being compact and light package with kinematically stiffer characteristics is commonly employed on passenger vehicle cars. Satisfactory performance of the steering system is determined by an acceptance test, which checks the composite error in the gear. The acceptance test checks the assembled gearbox for its torque characteristics instead of checking the individual components. The torque required by the pinion to rotate is the ‘Free Pinion Torque’ (FPT). FPT on Assembly varies within a range of 0.4-0.6 N-m, even if the tolerances on individual components (such as PCD run out of pinion, rack bend) are maintained within close tolerances. A virtual prototype of Rack and pinion steering gear is made in ADAMS [Automatic Dynamic Analysis of Mechanical Systems). This model will help to identify critical parameters and their effects on the assembly.
In order to insure that the remanufactured and/or rebuilt steering gear has and maintains the reliability and performance associated with a new OEM steering gear, it is essential that the following procedures be followed; if in-house engineering capabilities are limited, it may be necessary to consult with an outside laboratory to insure all testing methods used meet with the requirements outlined in this paper.
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