Whenever your machine’s precision movement drive exceeds what can easily and economically be performed via ball screws, rack and pinion may be the logical choice. On top of that, our gear rack comes with indexing holes and installation holes pre-bored. Simply bolt it to your framework.
If your travel duration is more than can be obtained from a single amount of rack, no problem. Precision machined ends enable you to butt additional pieces and keep on going.
The teeth of a helical gear are set at an angle (relative to axis of the gear) and take the shape of a helix. This enables the teeth to mesh gradually, starting as point contact and developing into collection contact as engagement progresses. One of the most noticeable advantages of helical gears over spur gears is usually much less noise, especially at moderate- to high-speeds. Also, with helical gears, multiple tooth are usually in mesh, this means much less load on each individual tooth. This outcomes in a smoother changeover of forces from one tooth to the next, so that vibrations, shock loads, and wear are reduced.
However the inclined angle of one’s teeth also causes sliding get in touch with between the teeth, which produces axial forces and heat, decreasing efficiency. These axial forces play a significant role in bearing selection for helical gears. As the Helical Gear Rack bearings have to withstand both radial and axial forces, helical gears require thrust or roller bearings, which are typically larger (and more costly) compared to the simple bearings used with spur gears. The axial forces vary in proportion to the magnitude of the tangent of the helix angle. Although larger helix angles offer higher rate and smoother motion, the helix position is typically limited by 45 degrees due to the creation 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 opposite hands mounted back-to-back, although the truth is they are machined from the same equipment. (The difference between the two styles is that dual helical gears have a groove in the centre, between the tooth, whereas herringbone gears usually do 
not.) This arrangement cancels out the axial forces on each set of teeth, so larger helix angles can be used. It also eliminates the need for thrust bearings.
Besides smoother motion, higher speed capability, and less sound, another advantage that helical gears provide more than spur gears may be the ability to be utilized with either parallel or nonparallel (crossed) shafts. Helical gears with parallel shafts require the same helix angle, but reverse hands (i.electronic. right-handed teeth versus. left-handed teeth).
When crossed helical gears are used, they can be of possibly the same or reverse hands. If the gears have got the same hands, the sum of the helix angles should the same the angle between your shafts. The most typical example of this are crossed helical gears with perpendicular (i.e. 90 level) shafts. Both gears have the same hand, 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 the shafts. Crossed helical gears provide flexibility in design, but the contact between teeth is nearer to point contact than line contact, so they have lower pressure capabilities than parallel shaft designs.