TWI426187B - Production method of concave cam and concave cam - Google Patents

Description

Concave cam and concave cam manufacturing method

The present invention relates to a method for manufacturing a concave cam and a concave cam, and more particularly to a method for manufacturing a concave cam having a high hardness and a self-lubricating effect.

A hinge is a rotating structure that pivots two components, and is commonly used in electronic products such as a cover for a pivotal notebook computer and a base or a flip-type mobile phone. The hub is formed by a fixed seat, a shaft disposed on the fixed seat, a plurality of spacers and a concave cam for providing a torque. Wherein, the concave cam provides a mechanical stroke for holding the lid to a specific positioning position to facilitate user operation.

Due to the difference in the rotational position of the lid, the torsion force carried by the concave cam changes reciprocally, and the difference between the maximum torque value and the minimum torque value is very high. If the concave cam is insufficient in hardness, it is easy to wear due to material fatigue after repeated use, thereby shortening and the service life. In order to strengthen the hardness, after the fabrication of the concave cam of the conventional technique, it is necessary to further pass a carburizing and quenching heat treatment step to change the crystal phase structure of the concave cam surface material, or to forge the surface hardness by forging or the like. This post-processing method requires more time and higher production costs.

In addition, the conventional concave cam is used to reduce the wear caused by multiple operations, and usually forms an oil storage groove on the friction surface thereof to provide a concave cam lubrication effect. However, when the concave surface of the concave cam opens the oil storage groove, the frictional area is reduced, resulting in insufficient torque value of the concave cam, which is easy to cause slippage, and is difficult to adsorb due to oil, and is easy to cause oil leakage after repeated use. It pollutes the entire organization and prevents the hub structure from functioning properly.

In view of the above-described problems of the prior art, it is an object of the present invention to provide a method of manufacturing a concave cam and a concave cam to solve the problem of insufficient strength of the conventional concave cam.

In accordance with the purpose of the present invention, a concave cam manufacturing method for manufacturing a concave cam includes the following steps: First, a plurality of powder substrates are provided, which are an iron substrate, a carbon substrate, and a chromium. Substrate. Next, a plurality of powder substrates are mixed. Next, a plurality of powder substrates are sintered to form a concave cam sintered structure. Finally, the chromium substrate on the surface of the concave cam sintered structure is vaporized to form a plurality of micropores on the surface of the sintered structure.

Wherein, after mixing the plurality of powder substrates, the step of injecting the plurality of powder substrates into a mold is further included.

Wherein, the plurality of powder substrates are further mixed with an adhesive, and the sintered structure is formed by injection molding of a metal powder.

Among them, the concave cam sintered structure is formed by adjusting a sintering temperature and a sintering pressure by a vacuum furnace.

Wherein, the chromium substrate located on the surface of the product structure is accelerated by withdrawing the gas in the vacuum furnace to reduce the saturated vapor pressure of the ambient atmosphere below the chromium substrate to form a plurality of microporous surfaces.

According to another object of the present invention, a concave cam comprising a concave cam structure having a plurality of micropores formed thereon, a microhole for storing a lubricant, and an average Rockwell C scale of a concave cam sintered structure (HR _{C) is} proposed ) is greater than 50.

According to the above, the concave cam manufacturing method of the present invention can form a concave cam sintered structure by mixing a higher carbon substrate and by powder metallurgy or metal powder injection molding, and then by a gasification sintered structure. The chromium substrate of the surface is formed to form micropores to produce a concave cam having high hardness and utilizing surface microporous oil storage and having a self-lubricating effect.

S11~S16‧‧‧Step process

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a flow chart showing the steps of an embodiment of the method for manufacturing a concave cam of the present invention.

The present invention relates to a concave cam and a concave cam manufacturing method. The concave cam has a concave cam structure, a plurality of micropores are formed on the surface thereof, and a lubricant is stored in the micropores. Among them, the average Rockwell hardness (HR _C ) of the concave cam sintered structure is greater than 50. Among them, the concave cam manufacturing method of the present invention is as follows.

Please refer to FIG. 1 , which is a flow chart of the steps of the embodiment of the concave cam manufacturing method of the present invention. In this embodiment, the concave cam manufacturing method can be used to manufacture a hinged concave cam and includes the following steps.

S11: providing a plurality of powder substrates, the plurality of powder substrates may be an iron substrate, a carbon substrate and a chromium substrate; S12: mixing a plurality of powder substrates; and S13: injecting the plurality of powder substrates To a mold; S14: sintering the plurality of powder substrates to form a concave cam sintered structure by powder metallurgy; S15: gasifying a chromium substrate on the surface of the concave cam sintered structure to cause sintering A plurality of micropores are formed on the surface of the structure; S16: soaking the concave cam sintered structure into a lubricant to store the lubricant into the plurality of micropores.

Wherein, the powder substrate may be further mixed with an adhesive, and the adhesive powder, such as grease or wax, adheres to the powder substrate to form a viscous flow by heating, and is formed by metal powder injection (metal In the form of injection molding, MIM), the injection is filled in a mold, and the adhesive adhered to the powder substrate is removed by solvent degreasing or thermal degreasing, and then sintered. among them The method of injecting the powder substrate into the mold can be carried out by injection or compaction. The method of mixing the powder substrate can be stirred and mixed by a kneading machine, and the hinge can be used for a notebook computer, a digital mobile device or a large camp screen display. Rotating mechanism, but not limited to this.

In addition, during the sintering process, the powder substrate can be formed by controlling the sintering temperature and the sintering pressure to cause an eutectoid reaction of the iron substrate and the carbon substrate due to solid diffusion or diffusion of the transient liquid phase. Iron-carbon co-deposition solid solution such as Ferrite, Austensite, Cementite (Fe ₃ C) or Pearite. Among them, Xueming carbon iron is a compound having an orthorhombic structure gap, so the hardness is very high and has high abrasion resistance. Therefore, the concave cam manufacturing method of the present invention can increase the precipitation amount of the ferritic carbon iron by adjusting the sintering temperature and the sintering time to mix and sinter the high-content carbon substrate (about 0.5% to 1.5%), so that the concave cam can be The method of solid solution strengthening, that is, by causing the solute atoms to enter the solvent crystal lattice, the crystal lattice is distorted to increase the strength and hardness of the solid solution, and the concave cam hardness value can be increased to a Rockwell hardness (HR _C ) of 50 or more. To effectively increase the torque load value.

In addition, the concave cam sintered structure can be disposed in a vacuum oven, adjust the sintering temperature and the sintering pressure, and evacuate the gas in the vacuum oven to maintain a vacuum state in the vacuum oven, by atmosphere (environment) The pressure is lower than the saturation vapor pressure of the chromium substrate to increase the gasification rate of the chromium substrate on the surface of the sintered structure, so that the surface of the sintered structure forms a plurality of micropores due to the evaporation of the chromium substrate.

In addition, by the above concave cam manufacturing method, the relative density outside the sintered structure can be maintained at 80-95%, and the relative density inside the sintered structure is 95-98%, so that the number of micropores on the outer side of the sintered structure is larger than the inner side. The number of micropores allows most of the lubricant to be stored on the outside of the sintered structure for optimum lubrication. In this embodiment, the lubricant may be implemented by oil or wax, but is not limited thereto.

In addition, the concave cam manufacturing method of the present invention can improve the unevenness by controlling the content of the chromium substrate. The anti-corrosion ability of the wheel.

In summary, the concave cam manufacturing method of the present invention has the effect that the high-content carbon substrate can be mixed and sintered by the powder metallurgy manufacturing technology, so that the iron substrate and the carbon substrate can form a high content by eutectoid reaction. The snowy carbon iron is used to increase the hardness value of the concave cam, so that the concave cam manufactured by the method of the invention can withstand the change of the reciprocating torque and the high torque bearing.

Another effect of the concave cam manufacturing method of the present invention is that the gas in the vacuum furnace can be evacuated to assist in vaporizing the chromium substrate on the surface of the sintered structure to form a plurality of micropores on the surface of the concave cam sintered structure. Lubricating oil can be stored to give the cam a self-cleaning effect without the need for an additional oil sump.

The above is intended to be illustrative only and not limiting. Any equivalent modifications or alterations to the spirit and scope of the invention are intended to be included in the scope of the appended claims.

S11~S16‧‧‧Step process

Claims (19)

A concave cam manufacturing method comprising the steps of: providing a plurality of powder substrates, wherein the plurality of powder substrates are an iron substrate, a carbon substrate and a chromium substrate; mixing the plurality of powder substrates; sintering the a plurality of powder substrates, wherein the plurality of powder substrates form a concave cam sintered structure; and gasifying the chromium substrate on the surface of the concave cam sintered structure to form a plurality of micropores on the surface of the sintered structure; The relative density of the outside of the concave cam sintered structure is lower than the relative density of the inside of the concave cam sintered structure. The concave cam manufacturing method according to claim 1, wherein the mixing of the plurality of powder substrates further comprises the step of injecting the plurality of powder substrates into a mold. The concave cam manufacturing method according to claim 2, wherein the plurality of powder substrates are further mixed with an adhesive, and the concave cam sintered structure is formed by metal injection-molding (MIM). . The concave cam manufacturing method according to claim 1, wherein the concave cam sintered structure is formed by sintering in a vacuum oven. The concave cam manufacturing method according to claim 4, wherein the chromium substrate in the surface of the concave cam sintered structure is assisted by gas extraction from the vacuum furnace. The concave cam manufacturing method according to claim 1, wherein after the plurality of micropores are formed on the outer side of the sintered structure, the concave cam sintered structure is further immersed in a lubricant to store the lubricant to the lubricant. The steps of a plurality of micropores. The method of manufacturing a concave cam according to claim 6, wherein the lubricant is oil or wax. The concave cam manufacturing method according to claim 1, wherein when the plurality of powder substrates form the concave cam sintered structure, the carbon substrate is subjected to a precipitation reaction with the iron substrate to harden the concave cam. Sintered structure. The concave cam manufacturing method according to claim 8, wherein the carbon substrate is subjected to the precipitation reaction with the iron substrate to form a swarf carbon iron (Fe ₃ C). The concave cam manufacturing method according to claim 9, wherein the ferritic carbon iron (Fe ₃ C) is formed by adjusting a sintering temperature and a sintering time of a vacuum furnace. The concave cam manufacturing method according to claim 1, wherein the plurality of powder substrates are combined into the concave cam sintered structure by a solid state diffusion or a transient liquid phase. The concave cam manufacturing method according to claim 1, wherein a relative density of the outer side of the concave cam sintered structure is 80-95%, and a relative density of the inner side of the concave cam sintered structure is 95-98%. The concave cam manufacturing method according to claim 1, wherein the concave cam sintered structure has an average Rockwell hardness (HR _C ) of more than 50. A concave cam comprising: a concave cam sintered structure, the surface of the concave cam sintered structure forming a plurality of micropores, the plurality of micropores storing a lubricant, and the average Rockwell hardness of the concave cam sintered structure (HR _C And greater than 50; wherein the relative density of the outside of the concave cam sintered structure is lower than the relative density of the inner side of the concave cam sintered structure. The concave cam according to claim 14, wherein the concave cam sintered structure is formed by mixing and sintering an iron substrate, a carbon substrate and a chromium substrate. The concave cam according to claim 14, wherein the concave cam sintered structure is formed by sintering in a vacuum oven. The concave cam according to claim 14, wherein the lubricant is oil or wax. The concave cam according to claim 15, wherein the carbon substrate and the iron substrate are formed by a precipitation reaction to form a ferritic carbon (Fe ₃ C). The concave cam according to claim 14, wherein the outer density of the concave cam sintered structure is 80-65%, and the inner density of the concave cam sintered structure is 95-98%.