Description of the characteristics of rack and pinion transmission

The characteristics of rack and pinion transmission are described below for reference.

1,gearIn a rotary motion, the rack moves in a straight line. The rack can be regarded as a part of a gear with an infinite number of teeth. At this time, each circle of the gear becomes a straight line, and the involute as a tooth profile curve also becomes a straight line.

The relationship between the straight line speed v of the rack and the gear index circle diameter d and the speed n is:

Where d is the diameter of the gear index circle, mm;

n is the gear speed, r/min.

The meshing line N1N2 and the base circle of the gear are tangent to N1. Since the base circle of the rack is infinite, the tangent point N2 between the meshing line and the base circle of the rack is at infinity.

2,Gear rackWhen meshing, regardless of whether the standard installation (the standard installation of gear and rack is the tangent of the index circle of the gear and the index circle of the rack), the meshing angleIt is always equal to the pressure angle a of the gear index circle, and it is also equal to the tooth profile angle of the rack; the pitch circle of the gear also coincides with the index circle constantly.

Only in the non-standard installation, the pitch line and the index line of the rack no longer overlap.

3. The condition for the correct meshing of gears and racks is that the basic tooth pitch is equal, and the basic tooth pitch of the rack is the vertical distance between the two adjacent tooth profiles on the same side of the straight line, ie.

4、齿轮齿条的实际啮合线为B1B2，即齿条顶线及齿轮齿顶圆和啮合线N1N2的交点B2及B1之间的长度。

The above description of the characteristics of rack and pinion transmission, including but not limited to, welcome to add if there are any deficiencies.