DE102018220305A1 - Alloy wheel with milled ventilation slots and manufacturing process - Google Patents

Abstract

The invention relates to a light metal wheel (100) with an integrally cast wheel body (110), which has a wheel rim (120) and a circular wheel disc (130) with a central wheel hub (140). According to the invention, the wheel disc (130) is designed as a solid disc and has a plurality of milled ventilation slots (150) which extend obliquely from the outside to the inside and produce a ventilation effect from the inside to the outside. The invention further relates to a manufacturing method for this vehicle wheel (100).

Description

The invention relates to a vehicle wheel made of light metal according to the preamble of claim 1 and a manufacturing method for this vehicle wheel.

A light metal wheel in the sense of the invention is a vehicle wheel made of light metal, in particular aluminum or magnesium, for a motor vehicle (in particular a passenger car or light commercial vehicle) without the car tire. A light metal wheel of this type has an annular rim on which the car tire is mounted and a circular wheel disc with a central wheel hub. Such a light alloy wheel can be produced in one piece (in the sense of one piece) by casting, as in the DE 10 2005 024 345 A1 described. The DE 10 2005 024 345 A1 also describes a vehicle wheel in which the central wheel hub of the wheel disc is supported by a plurality of radially extending spokes within the rim. As is known, such spokes enable a reduction in weight or mass and also the ventilation of a wheel brake of the motor vehicle arranged behind or in the vehicle wheel.

In the DE 10 2014 115 185 A1 describes a wheel made of light metal, the spokes of which are formed with openings. Through these openings, the heat transport through the spokes is reduced and the best possible heat release, the heat energy given off by the brake to the wheel hub, to the surrounding air. The openings can be formed during the casting of the wheel, in particular by arranging corresponding cores in the casting mold during the casting.

The invention has for its object to provide a light alloy wheel that enables improved cooling of the wheel brake and that is easy to manufacture.

The object is achieved by the light metal wheel according to the invention with the features of patent claim 1. With the subordinate patent claim, the invention also extends to a manufacturing method for the light metal wheel according to the invention. Preferred developments and refinements of the invention result analogously for both subject matter of the invention from the dependent patent claims, the following description of the invention and the drawing.

The light alloy wheel according to the invention has a one-piece, d. H. cast base or wheel body in one piece, which has a wheel rim and a circular wheel disc with a central wheel hub. According to the invention, the wheel disc is designed as a solid disc and has a plurality of milled or milled ventilation slots which extend obliquely (through the wheel disc) from the outside to the inside and (with the vehicle wheel rotating) bring about a ventilation effect from the inside to the outside.

The term “solid disk” means that the wheel disk is designed as a full-surface circular disk at least on the outside of the wheel body and an essentially, ie. H. apart from the ventilation slots, it forms a closed, in particular essentially flat, top surface. The outside is the side facing the viewer when the wheel is mounted. The opposite side is the inside, on which the wheel brake is typically also located.

The term “ventilation slot” means an elongated, narrow opening, in particular in the form of an elongated hole, which preferably has a constant width, for example, along its longitudinal direction. B. 5 mm to 15 mm, is formed. The term "oblique" means that the bore or working axis of the opening or the elongated hole is inclined (e.g. between 110 ° and 130 °) so that the inner surfaces along the long sides of the elongated hole or slot are oblique or are formed obliquely to the outside and inside of the solid disc and thus ultimately also obliquely or obliquely to the axis of rotation of the wheel. Since such oblique ventilation slots cannot be formed, or can only be formed in a very complex manner, due to the undercuts when casting the wheel body, machining by means of milling is provided according to the invention, the wheel disk being milled through at the provided locations to produce through openings.

The slanted ventilation slots are designed so that when the vehicle wheel is rotating (without additional components) there is a ventilation effect from the inside out. The wheel disc with the ventilation slots formed therein thus functions as a kind of exhaust air or ventilation fan, which draws in air on the inside and releases it to the outside on the outside. This ventilation effect is brought about by the sloping inner surfaces of the ventilation slots, the inner edges (on the inside) being in the direction of rotation of the wheel in front of the corresponding outer edges (on the outside), ie leading. In comparison to an undefined swirling of spokes, the invention enables a much better cooling of the wheel brake with simultaneous improvement of the aerodynamics on the outside. The invention is particularly suitable for rear axle wheels, since the brakes on the rear axle of a motor vehicle are less exposed to a cooling airstream compared to the brakes on the front axle.

The light alloy wheel according to the invention can have up to 20 ventilation slots and more, which can be evenly distributed or grouped. In a grouped arrangement, lamellar webs can be formed between the ventilation slots.

The ventilation slots preferably run in the radial direction or at least approximately (for example in a range of +/- 6 °) in the radial direction. The ventilation slots can be formed with the same (radial) length or also with different (radial) lengths.

Several spokes which connect the wheel hub and the wheel rim can be formed on the inside of the wheel disc and thus not visible from the outside. A group of several ventilation slots is preferably arranged between these spokes.

The outer edges (see above) and / or the inner edges (see above) of the ventilation slots are preferably designed with rounded radii in order to prevent edge corrosion. The rounded edges are preferably cast, i. that is, the rounding radii are already formed when the wheel body is cast. Ordinary deburring after milling may also be sufficient on the inner edges.

The ventilation slot openings on the outside and the ventilation slot openings on the inside can be offset from one another due to the inclined or oblique design of the ventilation slots, so that the wheel disc in the front view (this corresponds to the vertical top view of the outside when the wheel is mounted on the motor vehicle) as a closed wheel disc or with a closed top surface appears. This means that the ventilation slots can only be seen in an oblique viewing direction.

• - Gießen, insbesondere im Vakuumdruckgussverfahren, eines einstückigen Rad(grund)körpers aus Leichtmetall, insbesondere aus einer Aluminium- oder Magnesiumlegierung;
• - Fräsen bzw. Einfräsen der schräg ausgerichteten bzw. sich schräg durch die Radscheibe erstreckenden Ventilationsschlitze in den Radkörper bzw. in dessen Radscheibe, insbesondere mit einer 5-Achsen-CNC-Fräsmaschine.

The method according to the invention comprises at least the following steps:

• - Casting, in particular in the vacuum pressure casting process, of a one-piece wheel (basic) body made of light metal, in particular of an aluminum or magnesium alloy;
• - Milling or milling of the obliquely aligned or obliquely extending ventilation slots in the wheel body or in the wheel disc, in particular with a 5-axis CNC milling machine.

When casting the wheel body, imperfections (such as porosities, cavities, etc.) in the area of the wheel disc, in particular in the area of the ventilation slots, should be avoided, since such imperfections would be exposed when milling or milling the ventilation slots. This can be achieved by making the wheel disc as thin-walled as possible, at least in the area of the ventilation slots (large wall thicknesses lead to porosities, cavities and the like). The wall thickness or thickness should, however, be at least so large that the melt does not solidify prematurely in the casting process. The wheel disk preferably has a wall thickness or thickness of only 4 mm to 6 mm, in particular of only about 5 mm, at least in the area of the ventilation slots.

When casting the wheel body, recesses are preferably pre-cast at the milling points (i.e. at the points where the ventilation slots will later be milled in), which allow the milling tool to be securely attached (with an inclined or inclined working axis) when milling the ventilation slots. When casting, quasi contact geometries for the milling tool are also cast, which then enable optimum milling tool engagement during milling or milling and in particular prevent the milling tool from slipping or bending. When casting the wheel body, rounding radii for the outer and / or inner edges of the ventilation slots can also be cast or cast onto the wheel body (see above).

After the casting or after its casting and before milling or milling the ventilation slots, the wheel body can still be mechanically processed (e.g. deburred and / or turned) and / or heat-treated. Furthermore, the wheel rim, in particular the rim base, can be flow-shaped. In flow forming, the wheel rim, in particular the rim base, is rolled into its final shape at high speed and under high pressure. After milling, the milling of the milled wheel body can also take place, at least some of which is applied to the wheel body.

• 1 zeigt die Außenseite eines erfindungsgemäßen Leichtmetallrads.
• 2. zeigt die Innenseite desselben Leichtmetallrads
• 3 zeigt einen Schnitt durch den Radkörper des Leichtmetallrads, gemäß dem in 1 angegebenen Schnittverlauf.
• 4 veranschaulicht den Ablauf eines erfindungsgemäßen Verfahrens zur Herstellung des Leichtmetallrads.

The invention is explained below with reference to the drawing. The features shown in the figures of the drawing and / or explained below can, regardless of certain combinations of features, be general features of the invention and further develop the invention accordingly.

• 1 shows the outside of a light alloy wheel according to the invention.
• 2nd . shows the inside of the same alloy wheel
• 3rd shows a section through the wheel body of the light alloy wheel, according to the in 1 specified cutting course.
• 4th illustrates the sequence of a method according to the invention for producing the light alloy wheel.

This in 1 and 2nd shown alloy wheel 100 has a one-piece or one-piece cast wheel body 110 who has an annular wheel rim 120 and a circular wheel disc 130 with a central wheel hub 140 (for fastening the wheel 100 on a motor vehicle axle). The wheel disc 130 is how very good in 1 recognizable as a substantially flat solid disc. In the wheel disc 130 are several, almost radial ventilation slots 150 formed with different radial lengths. A ventilation slot 150 is a narrow, through the wheel disc 130 extending opening with an elongated or elongated shape. The ventilation slots 150 are in spaces from the inside or the back of the wheel disc 130 trained spokes 170 for example arranged in groups of four. Between the ventilation slots 150 One group has narrow, lamellar webs 160 . The alloy wheel 100 has an intended direction of rotation D.

As in 3rd clarifies, the ventilation slots extend 150 diagonally from the outside (top) to the inside (bottom), which means when the wheel is rotating 100 In the intended direction of rotation D, a ventilation effect is brought about from the inside to the outside, as illustrated by the flow arrows S. At the ventilation slots 150 are the outer edges 152 (on the outside) and the inside edges 154 (on the inside) with rounded radii.

As with the 4th illustrates the one-piece alloy wheel 100 by pouring (step 10th ) of the wheel body 110 and subsequent milling or milling (step 30th ) of the oblique ventilation slots 150 in the wheel center 110 , the wheel disc 130 is milled through at the relevant points. The helix or milling angle W is, for example, 110 ° to 130 °. In 3rd the material area is dashed M indicated that during milling, ie during milling, by a milling tool 200 is removed.

The wheel disc 130 is in the areas or spaces between the spokes 170 in which the ventilation slots 150 are arranged, as thin-walled as possible to avoid missing parts and the milling of the ventilation slots 150 to favor. The wall thickness or thickness in these areas is, for example, only 4 mm to 6 mm, preferably only 5 mm. When casting in these areas, the adjacent spokes 170 , which act as feed channels, achieve a very good mold filling from two directions.

It is preferably provided that when casting the wheel body 110 (ie in step 10th ) linear or at least point-like depressions at the milling points V be pre-cast when milling the ventilation slots 150 (from outside) a safe milling intervention of the tool 200 enable as in 3rd shown. Furthermore, the rounding radii on the outer edges can also 152 and / or inner edges 154 be poured so that they no longer have to be machined.

Optionally, the wheel center 110 before milling or milling the ventilation slots 150 machined, heat treated and / or its rim well 120 Flow-shaped (step 20th ). After milling the ventilation slots 150 you can optionally apply a varnish (step 40 ).

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102005024345 A1 [0002]
• DE 102014115185 A1 [0003]

Claims (10)

Light metal wheel (100) with a one-piece cast wheel body (110), which has a wheel rim (120) and a circular wheel disc (130) with a central wheel hub (140), characterized in that the wheel disc (130) is designed as a solid disc and several Has milled ventilation slots (150) which extend obliquely from the outside to the inside and cause a ventilation effect from the inside to the outside. Alloy wheel (100) after Claim 1 , characterized in that the ventilation slots (150) run at least approximately in the radial direction. Alloy wheel (100) after Claim 1 or 2nd , characterized in that spokes (170) are formed on the inside of the wheel disc (130), a group of ventilation slots (150) being arranged between each of these spokes (170). Light metal wheel (100) according to one of the preceding claims, characterized in that the outer edges (152) of the ventilation slots (150) are formed with rounding radii. Light metal wheel (100) according to one of the preceding claims, characterized in that the ventilation slot openings on the outside and the ventilation slot openings on the inside are offset from one another in such a way that the wheel disc (130) appears as a closed wheel disc (130) in the front view. A method of manufacturing a light alloy wheel (100) according to one of the preceding claims, comprising the following steps: - Casting the one-piece wheel body (110) from light metal; - Milling the obliquely aligned ventilation slots (150) in the wheel body (110). Procedure according to Claim 6 , characterized in that when the wheel body (110) is cast, depressions (V) are pre-cast at the milling points, which allow a milling tool (200) to be securely engaged when milling in the ventilation slots (150). Procedure according to Claim 6 or 7 , characterized in that when the wheel body (110) is cast, rounding radii for the outer edges (152) of the ventilation slots (150) are also cast. Procedure according to one of the preceding Claims 6 to 8th , characterized in that the wheel body (110) is mechanically processed, heat-treated and / or its rim well is flow-shaped before the ventilation slots (150) are milled in and / or that a coating is applied after the ventilation slots (150) are milled in. Procedure according to one of the preceding Claims 6 to 9 , When casting the wheel body (110) in the area of the ventilation slots (150), defects are avoided.

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