Rack and pinions are used for lifting mechanisms (vertical movement), horizontal movement, positioning mechanisms, stoppers and to permit the synchronous rotation of several shafts in general industrial machinery. On the other hand, also, they are found in steering systems to improve the direction of vehicles. The features of rack and pinion systems in steering are as follows: simple structure, high rigidity, little and lightweight, and superb responsiveness. With this system, the pinion, installed to the steering shaft, is definitely meshed with a steering rack to transmit rotary movement laterlly (switching it to linear motion) so that you can control the wheel. Furthermore, rack and pinions are used for various other purposes, such as playthings and lateral slide gates.
As a mechanical element to Spur Gear Rack transfer rotary into linear movement, gear racks tend to be compared to ball screws. There are advantages and disadvantages for using racks in place of ball screws. The benefits of a gear rack are its mechanical simplicity, huge load carrying capacity, no limit to the space, etc. One disadvantage though may be the backlash. The advantages of a ball screw are the high precision and lower backlash while its shortcomings are the limit in length due to deflection.
There are applications where the gear rack is stationary, as the pinion traverses and others where in fact the pinion rotates on a fixed axis as the gear rack moves. The previous is used widely in conveying systems while the latter can be utilized in extrusion systems and lifting/lowering applications.
To provide many variations of rack and pinion, KHK has various kinds of gear racks in stock. If the application takes a long length requiring multiple gear racks in series, we have racks with the tooth forms correctly configured at the ends. They are described as “equipment racks with machined ends”. When a equipment rack is created, the tooth cutting process and heat treatment process can cause it to try & walk out true. We can control this with special presses & remedial processes.