Rack and pinions are used for Spur Gear Rack lifting mechanisms (vertical movement), horizontal motion, positioning mechanisms, stoppers and to permit the synchronous rotation of many shafts in general industrial machinery. However, also, they are found in steering systems to improve the direction of cars. The characteristics of rack and pinion systems in steering are the following: simple framework, high rigidity, little and lightweight, and excellent responsiveness. With this system, the pinion, mounted to the steering shaft, can be meshed with a steering rack to transmit rotary motion laterlly (transforming it to linear movement) so that you can control the wheel. Furthermore, rack and pinions are used for several other purposes, such as toys and lateral slide gates.
As a mechanical element to transfer rotary into linear movement, gear racks are often compared to ball screws. There are advantages and disadvantages for using racks in place of ball screws. The benefits of a equipment rack are its mechanical simplicity, large load carrying capacity, no limit to the length, etc. One drawback 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 the pinion rotates upon a fixed axis while the gear rack moves. The previous is used broadly in conveying systems while the latter can be utilized in extrusion systems and lifting/lowering applications.
To provide many variants 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”. Whenever a equipment rack is produced, the tooth cutting procedure and heat treatment process could cause it to try & go out of true. We are able to control this with unique presses & remedial processes.