METHOD AND MEANS FOR THE MANUFACTURE OF A WHEEL CONSTRUCTION OF PLASTIC MATERIAL FOR VEHICLES OR SIMILAR

Abstract: A method and a means for the manufacture of a wheel construction (2) of plastic material for vehicles or similar, which comprises a number of spokes (2A-2H), a hub (2J) and a rim (2I) together constituting an integrated unit. By means of the invention it is made possible to manufacture a wheel construction, the strength property of which is high. The plastic material is injected in a mould (1), the cavity (7) of which exhibits a form corresponding to the one of the desired wheel construction, the design of the wheel being chosen to comprise an even number of spokes (2A-2H). The inlets (3-6) are located at such points near to every second one of the spoke portions (2A-2H) forming part of said mould (1), that the zones (7'), where the flows of material join each other, will be located near to points, where the spoke portions (2B, 2D, 2F, 2H), free from inlets, blend into the rim (2I).

Description: Method and means for the manufacture of a wheel construc¬ tion of plastic material for vehicles or similar The present invention relates to a method and a means for the manufacture of a wheel construction of plastic material for vehicles or similar, which comprises a number of spokes together with a hub and a rim forming a integrated unit. In previously known methods for the manufac ture of similar wheel constructions of plastic material th gates of the mould for the injection of plastic material h been designed in such a manner that the points, where the material flows are joined, the fusing line, will be locate at points, which adversely affect the strength of the wheel construction, by way of example on the rim between two spo The strength of the wheel construction has thereby been qu .substantially affected in a negative manner, as such portio of such a wheel made of plastic material ' and subjected to a load in zones, where the material flow of the plastic exhib discrepances, run the risk of suffering breakages in said zones. It is a principal object of the invention to provide a method for the manufacture of a wheel constructio of plastic material of the type mentioned above, in which t material flows, the fusing lines, will be located at such points of the wheel construction, that the strength proper¬ ties of the construction are essentially improved compared with such wheel constructions of the prior art. Said object is obtained by means of a method according to the present invention, which is substantially characterized by injecting the plastic material in a mould, the cavity of which exhibits a shape that corresponds to th one of the desired wheeel construction, the design of the wheel being chosen to comprise an even number of spokes and the gates being located at such points near to every second one of the spoke portions of said mould that the zones, where the flows of material join each other, will be locat- ed near to the points, where the spokes, free from inlets, blend into the rim. The invention is described in the following, reference being made to the accompanying drawing, in which Fig. 1 is a schematic view of a mould suit¬ able for use in connection with a method according to the present invention, Fig. 2a-e are schematical views showing different phases of the flow of the plastic material in a mould in connection with a method according to the present invention, and Fig. 3 is a view of the manner, in which a moulded wheel construction of plastic material is taken out of the mould, in which it has been moulded. A mould 1 suitable to be used in connection with a method for the manufacture of such a wheel construc¬ tion, that is related to the present invention, can suitabl be of the kind, which is illustrated in Fig. 1 of the drawi Such a mould that serves as an example only comprises a low part 1A and an upper part IB, which are designed to be put together in a tight fit and to be separated from each other in order to permit the extraction of a moulded wheel con- struction 2, as is shown in Fig. 3. The mould 1 can also be designed in such a manner that it can be split up in more components than the two illustrated parts. The low part can for example be designed in such a manner that it can be spl across the plane of rotation of the same and of the wheel i order to facilitate the extraction of a moulded wheel from the mould, and especially, if the wheel exhibits a complica ed profile with undercut portions etc. making it impossible to extract such a wheel from the mould in the manner illust rated in Fig. 3. The mould 1 is provided with a suitable num¬ ber of injection inlets. Said inlets can then to advantage be arranged as connecting inlets 3, 4, 5 and 6 of the lid of the mould IB, as is shown in Figs. 1 and 3. The lower portion 1A of the mould 1 exhibit a cavity 7, which together with the lid IB defines a form that corresponds to the desired wheel construction. A pin 8 for the hub and a number of sector-shaped mould elements 9 which are distributed round said pin 8, are received in a circular recess, which defines the periphery of the peri pherical form of the desired wheel construction, and there by form the core of the mould 1. In the illustrated example the mould 1 is designed to form a wheel construction 2 exhibiting eight spokes 2A-2H, but the mould can of course be designed, so that a wheel construction can be provided with fewer or more spokes than what is the case in the illustrated exampl However, it is essential that the wheel construction is pro vided with an even number of spokes, as it is otherwise not possible to make a wheel construction of plastic material, which exhibits sufficient strength properties. The method to manufacture a wheel construc¬ tion illustrated in the drawing by means of a mould illustr ed in the drawing. is carried out in the following manner: The plastic material is injected in liquid form in the inle 3-6 of the mould part IB, which in this position fits tight ly to the lower part 1A. The inlets 3-6 are in such a posi¬ tion that they debouch in the cavity 7 of the mould, which cavity exhibits the form, that corresponds to the desired wheel construction, and in the zone of every second one of the spoke portions 2A, 2C, 2E and 2G, by way of example at the mid-portion of the same. The distribution of the flow of the plastic material in the cavity 7 is marked with a darker shade than the empty space of the cavity 7, which shall be completely filled with plastic material, that is illustrated with a lighter shade. Arrows mark in the draw- ing the direction of flow of the plastic material in said cavity 7. The material first flows in the radial direction of the spokes 2A, 2C, 2E and 2G in direction towards the cavity for the rim 21 and inwards towards the pin 8. As the plastic material fills up said zones the spokes 2A-2H, the rim 21 and the.hub 2J are formed in the mould. As is evident from Fig. 2 the joining of flows of plastic material takes place in the zones 7 * nea-r to the points where the spoke portions 2B, 2D, 2F and 2H, free from inlets, blend into the rim 2 . - The ready--moulded wheel construction 2 is thereafter extracted of the mould 1, when the mould parts 1A, IB have been separated from each other, as is shown in Fig. 3, in order to be subjected to possible subsequent machining operations. The invention is not limited to the embodi¬ ment illustrated in the drawing and described above, but can be varied within the scope of the following claims. Other designs of the moulds than the ones shown are of course possible. The mould parts can for examp le be designed in such a manner that the plane for the whee construction in the mould will be substantially vertical. OMH /» YIFO

Claims: C l a i m s 1. Method for the manufacture of a wheel con¬ struction (2) of plastic material for vehicles or similar comprising a number of spokes (2A-2H) , a hub (2J) and a ri (21) together constituting an integrated unit, c h a r a c t e r i z e d b y injecting the plastic material in a mould (1) , the cavity (7) of which exhibits a form that corresponds to the one of the desired wheel construction, the design of the wheel being chosen to comprise an even number of spokes (2A-2H) and the inlets (3-6) being locate at such points near to every second one of the spoke por¬ tions (2A-2H) of said mould (1) that the zones (7 1 ), where the flows of material join each other, will be located nea to the points, where the spoke portions (2B, 2D, 2F, 2H) , free from inlets, blend into the rim (21) . 2. Mould for carrying out the method specified in claim 1, -c h a r a c t e r i z e d b y said mould (1) exhibiting a cavity (7) , the form of which corresponds to the one of the desired wheel construction (2) , i.e. exhibit ing an even number of spoke-forming portions, inlet gates (3-6) debouching near to every second one of the spoke- forming portions forming part of the mould (1) . O PI

Inventors: OLSSON JAN GUSTAF, SAMUELSSON LARS ERIK
Applicants: ITERA COMPONENTS AB, OLSSON JAN GUSTAF, SAMUELSSON LARS ERIK
Application year: 1982
Main classification: B29C5
IPC codes: B29C45, B60B5, B62D1