Rack and pinion mechanism

A rack and pinion mechanism, particularly suitable for use with a vehicle steering system, includes a pinion shaft 10 having pinion teeth 11 engageable with rack teeth 21 in a rack shaft 20. A pressure portion 31, typically in a rack guide 30, is provided at a side of rack shaft 20 opposite rack teeth 21 to press rack shaft 20 towards pinion shaft 10. A first elastic body, typically a coil spring 51, biases pressure portion 31 towards pinion shaft 10 by a first elastic restoring force, and a second elastic body, typically a coil spring 52, biases pressure portion 31 away from pinion shaft 10 by a second elastic restoring force, where in an initial state the first force towards pinion shaft 10 is greater than the second force away from pinion shaft 10; preferably the spring rate of first elastic body 51 is greater than that of second elastic body 52. In an embodiment, a receiving portion 32 is provided facing pressure portion 31 in an integral body carrying rack shaft 20, with elastic bodies 51, 52 at opposite ends of rack guide 30.