Features of Motiontite
High Anti-Loosening Power of Individual Bolts
Normal tightening alone works to prevent loosening. With the thread inclined slightly from the basic profile towards the bearing surface, when tightening, contact is gradually made from the tip of the external thread flank to the external thread flank. As load is applied, the external thread is elastically deformed, with force working to return it towards the bearing surface, and this strong repulsive force towards the contact surface prevents loosening. (The entire screw thread works as a powerful spring).
The recommended torque is the same as for standard bolts (1.0 to 1.2 times). Tightening torque and axial force have a proportional relationship, but here the feature is that the rotation angle is about 10% larger than for standard screws.
1.2 Times Higher Fatigue Strength
The main structural disadvantage of external threads are their extremely disproportionate structure, where more than 30% of the total load is applied to the initial thread engagement, causing maximum stress in the bottom of the thread. Therefore, when a certain amount of external force is applied, this can lead to fatigue failure from the bottom of the first thread. By slightly warping the screwing thread, the Motiontite reduces the load on the first engaging thread, improving fatigue strength.
The following are considered to be the benefits.
- Reduce the number of bolts.
- Reduce the length of the bolt screw.
- Reduce the size of bolts.
1) No loosening despite downsizing
2) Capability of comparatively high axial force setting
Even a screw made of a stainless steel having a high friction coefficient does not cause seizure. Motiontite, which causes contact gradually from male thread top portions during tightening, can prevent concentration of a friction heat. Thus, adhesion does not occur even if a screw, which is made of a stainless steel having a high thermal expansion coefficient, is tightened.
Generally, application of a lubricant, surface treatment or the like is performed to reduce the friction coefficient. In contrast, Motiontite exerts excellent performance also in terms of workability and cost.
Stable Axial Force even Without Lubricant
When axial force tests are carried out on standard screws, the axial force variance is so bad it is embarrassing. It is not uncommon for a test of just 10 screws to produce a difference in maximum and minimum axial force of about two times.
There are many issues to be considered, including the variance of friction coefficients for screw parts, and these make it difficult for designers to determine the size of the screw.
In the base state (without lubricant) after heat treatment and prior to surface treatment, axial force testing will show a clear difference in variance with standard products. In addition, in 10 consecutive repetitions of testing, some standard products will break after several repetitions, but the Motiontite maintains a small range of variance. It depends on the type and whether the surface has been treated, but Motiontite is able to reduce the ±30% of axial force variance to about 1/2, eliminating design waste for excess quality.
Low Cost, High Quality, Re-Usable
Low cost production has been realized through the rolling process. When adhesives or other anti-loosening products are used, substituting them with the Motiontite can result in definite cost reductions.
Because the Motiontite conforms to the tolerance ranges of JIS (Japanese Industrial Standards) and ISO International Standards, it can be used in place of existing screws for higher quality. Anti-loosening management (pitch, thread angle, and effective diameter management) is carried out using specialized Motiontite ring gauges.
In the case of bolts that are heat treated (strength classes 8.8, 10.9, 12.9), they can be re-used as long as the elastic force of the thread is maintained. The Motiontite displays strong anti-loosening power for hot-dip galvanized products and large diameter bolts.
For the time being we will target the sale of heat treated products (strength classes 8.8, 10.9, 12.9) in order to maintain elastic threads.