Injection molding manufacturing method for plastic worm wheel and injection molding die assembly

Abstract

The invention relates to an injection molding manufacturing method for a plastic worm wheel, which comprises the following steps that: a die assembly process is performed, a plurality of fan-shaped and tooth-shaped die sheets of the worm wheel are arranged in a left die body assembly, and the fan-shaped and tooth-shaped end parts of the die sheets can form the appearance outline of the plastic worm wheel; plastics are melted and injected into a worm wheel die body cavity; when the fan-shaped and tooth-shaped die sheets of the worm wheel demolds and withdraws, the demolding interference of theplastic worm wheel is possible to occur, but the plastic worm wheel can be contracted towards the center of the plastic worm wheel to generate displacement to allow the die sheets to break away from the solid plastic worm wheel automatically; tooth-shaped gear rings on the plastic worm wheel are formed by the die sheets; and a finished product of the plastic worm wheel can be obtained finally by a demolding process. In an injection molding die assembly adopted in the method, a motor is arranged on the left die body assembly, the motor is provided with the fan-shaped and tooth-shaped die sheets of the worm wheel by a transmission piece, and the die sheets are matched with a right die body assembly. Compared with a plastic bevel gear, the contact strength of the plastic worm wheel manufactured by the method is increased by 30 to 50 percent, the service life is prolonged obviously, a manufacturing process is feasible, injection molding and demolding are easy, and the injection molding die assembly has a skillful, practical and reliable structure.

Description

technical field [0001] The invention relates to a plastic worm wheel, in particular to an injection molding manufacturing method of a plastic worm wheel and an injection mold assembly thereof. Background technique [0002] The transmission pair composed of worm and plastic helical gear has simple structure, large reduction ratio, stable transmission, low noise, and convenient manufacture, and the injection mold for producing plastic helical gear is easy to manufacture, easy to demould, and does not require machining. Therefore, this type of transmission structure is often used in miniature and small reduction gears, and is widely used in various motors with reduction gears in automobiles, such as wiper motors, window regulator motors, seat motors, sunroof motors, etc. [0003] In the worm and plastic helical gear transmission, the worm armature shaft is generally made of steel and heat-treated, while the helical gear is made of high-strength plastic (POM, etc.) by injection ...

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Problems solved by technology

[0004] For this reason, the transmission pair composed of worm and plastic worm gear is used in the design to replace the combination of worm and plastic helical gear, so that the plastic worm gear has high strength and service life. If the plastic worm gear is obtained by mechanical processing, due to the size of the plastic worm gear Very small, the size of the hob for processing the worm gear is very small, it is not suitable to manufacture the hob for machining, and the processing cost is very high

However, it is difficult to demould with ordinary injection molding methods. Therefore, an injection molding manufacturing method of plastic worm gears using a new technology of fan-shaped tooth molds and the invention and innovation of the injection mold clamping mechanism came into being.

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