Helical gears are often the default choice in applications that are ideal for spur gears but have non-parallel shafts. They are also used in applications that require high speeds or high loading. And whatever the load or swiftness, they often provide smoother, quieter operation than spur gears.
Rack and pinion is useful to convert rotational movement to linear movement. A rack is straight teeth cut into one surface area of rectangular or cylindrical rod formed materials, and a pinion is definitely a small cylindrical gear meshing with the rack. There are plenty of methods to categorize gears. If the relative position of the apparatus shaft is used, a rack and pinion belongs to the parallel shaft type.
I have a question regarding “pressuring” the Pinion into the Rack to lessen backlash. I’ve read that the larger the diameter of the pinion gear, the less likely it will “jam” or “stick into the rack, but the trade off is the gear ratio boost. Also, the 20 level pressure rack is better than the 14.5 level pressure rack for this use. Nevertheless, I can’t find any info on “pressuring “helical racks.
Originally, and mostly due to the weight of our gantry, we had decided on larger 34 frame motors, spinning in 25:1 gear boxes, with a 18T / 1.50” diameter “Helical Gear” pinion riding on a 26mm (1.02”) face width rack because given by Atlanta Drive. For the record, the electric motor plate is usually bolted to two THK Linear rails with dual cars on each rail (yes, I know….overkill). I what after that planning on pushing up on the electric motor plate with either an Atmosphere ram or a gas shock.
Do / should / may we still “pressure drive” the pinion up into a Helical rack to further decrease the Backlash, and in doing this, what will be a good starting force pressure.
Would the use of a gas pressure shock(s) work as efficiently as an Air ram? I like the idea of two smaller drive gas shocks that equal the total force required as a redundant back-up system. I would rather not run the air flow lines, and pressure regulators.
If the idea of pressuring the rack is not acceptable, would a “version” of a turn buckle type device that would be machined to the same size and shape of the gas shock/air ram work to modify the pinion placement in to the rack (still using the slides)?

But the inclined angle of the teeth also causes sliding contact between your teeth, which generates axial forces and heat, decreasing efficiency. These axial forces play a significant part in bearing selection for helical gears. Because the bearings have to withstand both radial and axial forces, helical gears require thrust or roller bearings, which are usually larger (and more expensive) than the simple bearings used in combination with spur gears. The axial forces vary compared to the magnitude of the tangent of the helix angle. Although larger helix angles offer higher quickness and smoother motion, the helix position is typically limited to 45 degrees because of the production of axial forces.
The axial loads produced by helical gears can be countered by using double helical or herringbone gears. These arrangements have the appearance of two helical gears with reverse hands mounted back-to-back again, although in reality they are machined from the same equipment. (The difference between your two styles is that dual helical gears have a groove in the middle, between the the teeth, whereas herringbone gears usually do not.) This set up cancels out the axial forces on each set of teeth, so bigger helix angles may be used. It also eliminates the necessity for thrust bearings.
Besides smoother motion, higher speed ability, and less sound, another advantage that helical gears provide more than spur gears may be the ability to be used with either parallel or non-parallel (crossed) shafts. Helical gears with parallel shafts require the same helix position, but opposite hands (i.e. right-handed teeth vs. left-handed teeth).
When crossed helical gears are used, they may be of either the same or opposite hands. If the gears Helical Gear Rack possess the same hands, the sum of the helix angles should the same the angle between the shafts. The most common exemplory case of this are crossed helical gears with perpendicular (i.e. 90 degree) shafts. Both gears possess the same hands, and the sum of their helix angles equals 90 degrees. For configurations with reverse hands, the difference between helix angles should the same the angle between your shafts. Crossed helical gears offer flexibility in design, but the contact between tooth is nearer to point get in touch with than line contact, therefore they have lower pressure capabilities than parallel shaft styles.