Main parameters of gear rack

The main parameters of a rack include: tooth slot width, tooth crest height, tooth root height, tooth height, tooth thickness, tooth root circle radius, etc. As shown in Figure 1.
Dental groove
The tooth groove is the concave part between the teeth of a gear.
The space between two adjacent teeth on a gear is called a tooth groove or interdental space. The size of the tooth groove is represented by the groove width, which can be divided into two types: end face groove width and normal groove width.
(1) End face tooth groove width (groove width) - the length of the indexing arc between the tooth profiles on both sides of a tooth groove on the end plane, represented by the letter e. The groove width on any circumference is represented by the letter ei.
(2) Normal slot width (normal slot width) - The arc length of the normal helix on both sides of a helical gear's tooth line located within a tooth slot is called the normal slot width.
Tooth tip
The part between the dividing circle and the tooth tip circle is called the gear tooth tip. The radial distance is called the tooth crest height, represented by the letter ha.
root
The part between the dividing circle and the tooth root circle is called the tooth root. The radial distance is called the tooth root height, represented by the letter hf.

Parameter selection
(1) Whether the gear's runout, full tooth depth, common normal, and tooth orientation are qualified, and whether the one tooth runout and pitch error exceed the tolerance.
(2) Is the installation distance of gears and racks appropriate after installation.
(3) The meshing clearance between the rack and gear should be 0.25 * modulus.
(4) Whether the full tooth depth, runout, common normal line, and especially the tooth orientation of the rack are qualified.