CONTINUOUSLY VARIABLE TOROIDAL TRANSMISSION

摘要

In a toroidal variator a plurality of rolling elements (20, 22) are in driving engagement with an input and output race (10, 14) at respective contact regions. Each rolling element (20, 22) is mounted on a carriage assembly (26) for rotation about a rolling axis, and is being free to pivot about a tilt axis, the tilt axis passing through the rolling element (20, 22) perpendicular to the rolling axis, and intersecting the rolling axis at a roller centre, whereby a change in the tilt axis causes a change in the variator ratio being the ratio of rotational speeds of the races. The tilt axis is arranged at an angle known as castor angle (see FIG. 4) to a plane (P) perpendicular to the variator axis (V). Each carriage assembly (26) can cause a movement of the rolling element (20, 22) with a component of rotation about a pitch axis (A, B). The pitch axis is defined as passing through the roller centre and through the contact regions. Pitching the roller elements (20, 22) causes them to tilt, thereby changing the transmission ratio.

主权项

1. A variator comprising:
an input surface and an output surface, the input and output surfaces being coaxially mounted for rotation about a variator axis, and a toroidal cavity being defined between the working surfaces; two rolling elements disposed between and being in driving engagement with the input and the output surfaces at respective contact regions, each rolling element being mounted on a carriage assembly for rotation about a rolling axis, each rolling element being free to pivot about a tilt axis, the tilt axis passing through the rolling element perpendicular to the rolling axis, and intersecting the rolling axis at a roller centre, whereby causes a change in the variator ratio being the ratio of rotational speeds of the races occurs with a change in tilt angle; wherein each carriage assembly is mounted for pivotal movement about a pitch axis that results in a change of a pitch angle of the rolling element, the pitch axis passing through the roller centre and through the contact regions; and the variator further comprising a control member operative to actuate at least one of the carriage assemblies to undertake the said pivotal movement thereby changing the pitch angle, so urging the plurality of rolling elements to pivot about their tilt axes and thereby provide a change in variator ratio.