Patent Application
20090263267
1. Field of the Invention
The present invention relates to a method for manufacturing a porous oil-impregnated revolving shaft assembly, and more particularly to a method for manufacturing a porous oil-impregnated revolving shaft assembly with multiple communicated pores receiving lubricating oil therein.
2. Description of related art
Generally, a revolving shaft assembly is used as a hinge in electronic devices, such as notebook, mobile phone, media player and so on. The revolving shaft assembly includes a driving member and a driven member interfereferingly and pivotally engaging with the driving member. Each of the driving member and the driven member has an inner surface intimately engages with each other. A plurality of holes is defined between the driving member and driven member to storage oil to lubricate the inner surfaces of the driving member and the driven member. A part of the inner surfaces of the driving member and the driven member where the oil can not reach is not lubricated. As a result, a serious friction occurs between the part of the inner surfaces of the driving member and the driven member and noise is unavoidable to occur after a period of use of the shaft assembly. The function and the lifespan of the revolving shaft assembly are accordingly affected and shortened.
It is therefore desirable to provide a method for manufacturing an improved revolving shaft assembly with a driving member and a driven member which can rotate smoothly relative to each other.
A method for manufacturing a porous oil-impregnated revolving shaft assembly includes following steps: 1) offering an amount of metal powder, a particle diameter of the metal powder ranging from 1 μm to 150 μm; 2) offering a mold having a cavity and filling the metal powder in the cavity of the mold to make a green piece, a plurality of pores being defined between the metal powder of the green piece; 3) heating the green piece at a high temperature to sinter the metal powder to obtain a sintered product, a volume ratio of pores of the sintered product ranging from 12% and 20%; 4) dipping the sintered product into oil to make the oil enter the pores of the sintered product thereby to obtain the desired final product.
Other advantages and novel features will become more apparent from the following detailed description of preferred embodiments when taken in conjunction with the accompanying drawings, in which:
Many aspects of the present embodiments can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present embodiments. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.
Referring to
Referring to
In this embodiment, the metal powder is manufactured by mechanical method, such as cutting, crushing, chipping, etc. Super fine metal powder acting as an additive is added to the fine metal powder to improve the sintering strength of the fine metal powder. The super fine metal powder accounts for 1%˜10% of the fine metal powder by weight. When the driving member 10 and the driven member are assembled together, inner surfaces of the driving member 10 and the driven member 20 are intimately engaged with each other. An oil film is formed between the inner surfaces of the driving member 10 and the driven member 20 to lubricate the whole of inner surfaces of the driving member 10 and the driven member 20. Thus, the driving member 10 and the driven member 20 can rotate smoothly relative to each other and the noise generated by the conventional revolving shaft assembly after a period of use thereof can be avoided by the present invention.
A method for manufacturing the porous oil-impregnated revolving shaft assembly in accordance with a second embodiment of the present invention comprises the steps of: 1) offering an amount of super fine metal powder (not shown), a particle diameter of each super fine metal powder ranging from 1 μm to 20 μm, wherein a particle diameter ranging from 5 μm to 20 μm is preferable; 2) offering a bonding agent (not shown) to mix with the super fine metal powder together to thereby obtain a mixture and injecting the mixture into a mold cavity (not shown) to obtain a green piece; 3) heating the green piece at a selected temperature to obtain a sintered product, wherein the super fine metal powder is sintered; 4) dipping the sintered product into oil to fill pores in the sintered product with the oil thereby to obtain a desired final product for forming the revolving shaft assembly.
In the second embodiment, the temperature of sintering is lower than that of the first embodiment, and the volume ratio of the porous of the desired final product is the same as that of the first embodiment.
It is believed that the present embodiments and their advantages will be understood from the foregoing description, and it will be apparent that various changes may be made thereto without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the examples hereinbefore described merely being preferred or exemplary embodiments of the invention.
