Pinions of synthetic resin
Strengthened synthetic resin consist of layers of materials of thin wood sheets, compressed and processed to an agglomerate with synthetic resin of high hardness as a binder.
The material, of particular formation, gives to the whole a high resistance for tensile and bending load (in the transverse direction of the material layers) while the synthetic resin ensures the hardness, impermeability by oil and resistance to acids.
The entire dried wood sheets, such as the material, ensures resistance and elasticity: penetrated with synthetic resin the wood fibers obtain even greater resistance and sufficient hardness against influence of oil and humidity.
One of the great advantages of these synthetic resins is the impermeability, which admits easy storage in a dry, cold or damp environment without influence on the form and resistance; it is not necessary to lubricate them abundantly with grease or mineral oil during operation, such as with metal pinions.
On the other hand, it is not necessary to strengthen these synthetic resins with side plates. Caution is, however, provided when one replaces a metal pinion by a pinion of synthetic resin; after all, if the breakage and wear resistance of the latter are compared with those of a bronze pinion, still it cannot endure big shocks. Our technical department is at your disposal to provide all the explanation.
The increasingly extensive applications of nylon and other super polymides as replacement material for metals are well known. In the field of “gears” these materials offer the advantage of a high impact resistance, a great wear resistance combined with good friction conditions, very easy adaptation and especially the low noise level of the gear meshing. Certain precautions should, however, be taken namely: the use of a metal nave, firmly attached in the nylon and in which one can provide a key way; a high pressure of the key on the nylon can result in pressing of this material with the inevitable occurrence of clearance, loosening, deformation. Such a nave also ensures a better fitting on the shaft.
- The transmission capacity of pinions of synthetic resin or super polyamide cannot be compared with these of the metal pinions.
Some synthetic materials absorb moisture if they are stored in humid warehouses or humid operating conditions for a longer period of time; as a result they will not retain its shape. It is necessary when using these synthetic materials to remind their specific application.
- The use of polyamides is, however, limited in the peripheral velocity up to 10 m/s and a temperature of 60⁰ C to 90⁰ C. At this temperature the transmission power is 2 to 3 times lower than at a temperature of 20⁰ C.
- On the other hand it is a fact that some gears are designed to work without lubricant. It is necessary to lubricate these at the start-up and every +/-200 hours-long operation.
See below in the material tables.