Rack and pinion steering device

摘要

A rack and pinion steering device which can restrict a pinion shaft from moving in an axial direction even when a snap ring of supporting a thrust load of the pinion shaft is detached or broken, and in which when the snap ring is detached or broken, the pinion shaft is moved to an upper side in the axial direction. Then, a raised portion of the pinion on a side of a lower end face is brought into contact with an outer peripheral face of a rack. The pinion shaft does not move further in the axial direction. Therefore, the thrust load can be supported, and a predetermined performance of the rack and pinion steering device can be maintained.

主权项

1. A rack and pinion steering device comprising:
a housing; a pinion shaft which is axially supported rotatably by the housing, and to one end of which a steering force of a steering wheel is transmitted; a pinion which is configured at another end of the pinion shaft; a rack which is brought in mesh with the pinion for transmitting the steering force to a side of a wheel; a large diameter shaft portion which is configured at one end of the pinion with a diameter thereof larger than a gear tooth root circle diameter of the pinion; a first bearing which is a ball bearing for axially supporting the large diameter shaft portion rotatably at the housing, the outer ring of the first bearing being inserted into a bearing hole and being fixed to the housing unmovably in an axial direction by a snap ring which is mounted to a ring-like groove on a side of an opening of the bearing hole; a small diameter shaft portion which is configured at another end of the pinion with a diameter thereof smaller than the gear tooth root circle diameter of the pinion; a second bearing which is a needle bearing for supporting the small diameter shaft portion rotatably at the housing; a first raised portion which is configured at a gear tooth root of the pinion on a side of the large diameter shaft portion; and a second raised portion which is configured at the gear tooth root of the pinion on a side of the small diameter shaft portion, wherein
a distal end of the first raised portion is configured by a diameter the same as a gear tooth tip circle diameter of the pinion,a distal end of the second raised portion is configured by a diameter smaller than the gear tooth tip circle diameter of the pinion,the second raised portion has a radius larger than a radial distance from the axis of the pinion to a rack tooth,the pinion shaft is moved to a side of the first bearing by a thrust load applied to the pinion,a length in an axial direction until an outer peripheral face of the rack is brought into contact with the second raised portion is configured to be smaller than a length in the axial direction by which the second bearing supports the small diameter shaft portion, andthe snap ring is located upstream of the first bearing, along a torque direction of the steering device.