The present invention relates to a method for making a gearmotor and in particular a method for making a gearmotor using a plastic material.
Prior art processes for making gearmotors usually involve mechanical machining to obtain a metal casing in which the gearmotor moving parts are assembled, for example, briefly, the ring gear and the pinion.
The classic processes involve making castings, several parts of which are subsequently machined using machine tools.
In general, the rough casing is made by casting. Once removed from the mould, it is deburred or in any case cleaned with the removal of shavings, holes are made where necessary, threads prepared, with restoration of the design tolerances essential for guaranteeing correct gearmotor operation and avoiding, in particular, seizing phenomena during operation.
In other words, a plurality of operations are carried out after casting, which have a significant effect on the cost of the finished product.
Moreover, for that reason, conventional processes are relatively long, since the above-mentioned mechanical machining means having to have available machine tools and storage warehouses for semi-finished products, with evident logistical complications in gearmotor production and assembly.
In this context, the main technical purpose of the present invention is to propose a method for making gearmotors which is free of the above-mentioned disadvantages.
The present invention has for an aim to propose a method which simplifies the mechanical machining on semi-finished products so as to reduce both the gearmotor production and assembly times and the relative costs.
The present invention also has for an aim to propose a method for making the gearmotor which overcomes the logistical complications and reduces or eliminates the times for which semi-finished products remain in the warehouses.
The technical purpose indicated and the aims specified are substantially achieved by a method for making gearmotors comprising the operating steps described in claim 1 and in one or more of the dependent claims herein.
Further features and advantages of the present invention are more apparent in the detailed description below, with reference to a preferred, non-limiting, embodiment of a method for making gearmotors and of a gearmotor, illustrated in the accompanying drawings, in which:
With reference to the accompanying drawings and in particular with reference to
The gearmotor 1, whose description is limited to understanding of the invention, comprises, schematically a casing 2, illustrated in particular in
It should be noticed that in the embodiment illustrated by way of example, the pinion 3 is a worm screw and the gear is a ring gear with relative slots 5 for engaging with the screw.
The pinion 3 is associated with a relative shaft 6 and the gear 4 is associated with a relative shaft 7.
The shaft 6 is connected to the casing 2 by relative bearings 8, 9 and the shaft 7 by relative bearings 10, 11, that is to say, the casing 2 supports the pinion 3 and the gear 4.
The method disclosed comprises the steps of preparing a mould 12 in which to make a casting using a plastic material to obtain the casing 2.
It should be noticed that the step of making the casing 2 consists of a step of injecting a molten plastic material into the mould 12, illustrated in particular in
It should be noticed that at the end of casting cooling in the mould 12, the casing 2 is ready for subsequent assembly of the gearmotor 1, since it does not require any further mechanical machining.
The pinion 3 and gear 4 with the relative shafts 6, 7 are housed in the casing 2 in respective cavities 13, 14.
The method disclosed comprises the step of making the cavities 13, 14, that is to say, hollows, in the casing 2, by moving respective male elements 15, 16 relative to the mould 12, as is schematically illustrated in
To keep the cavity 13 tolerances suitable for gearmotor 1 operation, the male element 15 is preferably cooled.
Similarly, to keep the cavity 14 tolerances suitable for gearmotor 1 operation, the male element 16 is cooled.
Advantageously, the method disclosed comprises the step of preparing the bearing 9 in the mould 12 so that it remains associated with the casing 2 after the molten material injected into the mould 12 has cooled.
To facilitate gearmotor assembly, the method disclosed also involves preparing the bearing 10 in the mould 12 so that it remains associated with the casing 2 after the molten material injected into the mould 12 has cooled.
The method comprises a step of making, in the casing 2, substantially annular cavities or grooves 17 in which means for fixing the shafts 6 and 7 are inserted.
In particular, with reference to the cavity 14 it should be noticed that the fixing means comprise an elastic ring 18 for fixing the shaft 7 by means of the bearing 11.
The mould 12 comprises a fixed block 19 and a movable block 20 which are drawn near, as illustrated in particular in
In particular with reference to
The outer portion 22 has a tooth 24 designed to define, during casing 2 casting, the hollow corresponding to the cavity 17.
Once the cavity 17 has been formed, according to the method the portion 23 of the male element 15, sliding in the direction V indicated in
It should be noticed that such a movement towards the axis R2 is made possible by the particular substantially tapered shape of the portions 22 and 23 and by the fact that the portion 22 is free to move, set in motion by the portion 23, relative to the mould 12.
Advantageously, the method comprises the step of preparing in the mould 12 threaded inserts 25 which remain associated with the casing 2 at the end of casting cooling so that they are available for fitting elements of the gearmotor which are not illustrated, for example connecting flanges.
Advantageously, the method comprises the step of molding in plastic material the gear 4 on the relative shaft 7 so as to speed up the production method.
Moreover, molding is preferably carried out by heating the mould 12, in particular to around 60° C.
The invention described brings important advantages.
The casing made in a single body by molding a plastic material allows the elimination of all mechanical machining normally needed after molding metal alloys, significantly reducing production costs.
Once ejected from the mould, the casing is ready for gearmotor assembly with evident simplification of the logistics for management of semi-finished products and warehouses.
The invention described above may be modified and adapted without thereby departing from the scope of the inventive concept defined in the claims herein.
Moreover, all details of the invention may be substituted by technically equivalent elements.
Number | Date | Country | Kind |
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BO2006A000561 | Jul 2006 | IT | national |