DE102020127595A1 - CAST WHEEL WITH A ROTATION AXLE FOR A MOTOR VEHICLE - Google Patents

Abstract

The invention relates to a cast wheel (1) with an axis of rotation (2) for a motor vehicle (3), having an inside (4) and an outside (5) visible when used in a motor vehicle (3). The cast wheel (1) is primarily characterized in that the outside (5) includes at least one sprue (6). The cast wheel proposed here meets the aesthetic requirements of the market, with the cast wheel being able to be manufactured with a few post-processing steps.

Description

The invention relates to a cast wheel with an axis of rotation for a motor vehicle, a casting mold for such a cast wheel, and a production method with such a casting mold for forming a cast wheel.

Cast wheels have long been known, for example as aluminum die-cast wheels for motor vehicles, and are colloquially also referred to as rims. Examples can be found in the U.S. 5,772,801 A and in the EP 3 225 335 A1 . Sprues are provided in the casting mold so that a casting process works properly, i.e. no premature solidification of the liquid material, usually a metal, occurs. Because breaklines occur at these points or, as a result of stressful post-processing, a visibly different surface compared to the non-post-processed cast surface, the casting aid has previously been arranged in an area of the cast wheel that is not visible in use, for example in a motor vehicle.

Proceeding from this, the present invention is based on the object of at least partially overcoming the disadvantages known from the prior art. The features according to the invention emerge from the independent claims, for which advantageous configurations are shown in the dependent claims. The features of the claims can be combined in any technically meaningful manner, in which case the explanations from the following description and features from the figures, which include additional embodiments of the invention, can also be used.

The invention relates to a cast wheel with an axis of rotation for a motor vehicle, having an inside and an outside that is visible in use in a motor vehicle.

The cast wheel is primarily characterized in that the outside comprises at least one sprue.

In the following, reference is made to the named axis of rotation if the axial direction, radial direction or the direction of rotation and corresponding terms are used without explicitly otherwise indicating. Unless explicitly stated otherwise, ordinal numbers used in the preceding and following description are only used for clear distinction and do not reflect any order or ranking of the components identified. An ordinal number greater than one does not necessarily mean that another such component must be present.

The cast wheel is suitable, for example, for conventional use in a motor vehicle, preferably without the use of a concealing hubcap, i.e. as a visible cast wheel, for example sold on the market as light metal rims made of an aluminum alloy, titanium alloy or magnesium alloy. The cast wheel proposed here can preferably be used as a replacement for a corresponding (for example a motor vehicle) conventional wheel. The conventional connections are preferably provided, such as a hub bore for connection to a wheel hub with wheel bearings and bores for wheel bolts, and a rim mouth with a rim flange for a tire. The axis of rotation of the cast wheel runs centrally balanced (as precisely as possible), for example through the hub bore. For example, the cast wheel is balanced with respect to the axis of rotation in that it is designed to be rotationally symmetrical. The outside and the inside of the cast wheel are provided transversely to the axis of rotation, that is to say with the axis of rotation as normal to a center plane. In use in a motor vehicle, the inside is oriented towards the wheel arch or towards the other wheel of the respective (two-wheeled) vehicle axle. Even with a strong steering angle, the inside is usually not visible during normal operation of the motor vehicle. Only the outside is permanently visible when in use in a motor vehicle and forms an important part of the aesthetic appearance of the motor vehicle.

It is now proposed here that the outside comprises at least one sprue, that is to say is the sprue side. In the casting mold used to manufacture the cast wheel, at least one sprue is provided on the later (that is, in use) outside of the cast wheel. The sprue is set up so that a sufficient casting quality is made possible inexpensively and with little production effort, that is to say while avoiding shrinkage distortion and the formation of cavities. Preferably with a few, particularly preferably a single, and / or central sprue aid (for example a feeder) for introducing casting material, the at least one sprue is guaranteed to have a sufficient thickness of the cavity in the casting mold to the areas of the casting wheel that are further away from the casting aid, so that an excessive Material congestion in the area in which such a sprue is provided is avoided during the casting process. In one embodiment, the at least one sprue is designed in such a way that the outside has an aesthetic that is in line with the market. The sprue or the outside is preferably reworked for a consistent appearance and / or quality.

It is also proposed in an advantageous embodiment of the cast wheel that the outside be reworked, with a casting aid preferably being arranged on the outside.

It is proposed here that the outside, preferably the entire outside, be reworked. Post-processing preferably includes machining, for example grinding and / or turning. Such post-processing is preferably also referred to as finishing. Only or in addition, the post-processing comprises painting, the painting optionally being carried out at least in part before machining. By means of painting and, if necessary, machining carried out afterwards, a plurality of different colors are preferably produced, for example black or colored lacquer and a free-turned point, so that in this area, preferably with the clear lacquer applied, the material of the cast wheel, particularly preferably in one (at least before machining) the area surrounding the sprue remains visible. Often, a basecoat is also provided as a primer, which improves the adhesive properties between the paints for a paint application and the outside and / or offers improved corrosion protection. Such a basecoat, at least when a clearcoat is used, is preferably colorless, that is to say clear or, in reaction with a clearcoat, is clear in a final state.

It is also proposed in an advantageous embodiment of the cast wheel that the outside is turned off, preferably turned to a gloss finish.

It is proposed here that the outside, preferably the entire outside, be reworked by means of turning, preferably so-called gloss turning. By means of the turning, the at least one sprue is at least partially, preferably completely, removed and the surface of the reworked area is evened out or a predetermined pattern is generated so that the sprue is no longer present or can no longer be recognized as such. Gloss turning is known for cast wheels, for example in the US 2014/915 243 A1 described. With the proposal here to arrange the sprue in the post-processing area by means of turning, a post-processing step for removing the sprue is omitted and / or the effort involved in producing a desired quality of the sprue is reduced. The cast wheel proposed here is particularly advantageous for wheels with axially very thin spokes, which have sufficient rigidity in the circumferential direction due to their width, because the cross-section required for the casting process or a minimum (here axial) width of the casting channel is formed to avoid material accumulation is in that the spoke additionally comprises a sprue that appropriately adapts the cross section. In that the at least one sprue is arranged on the outside and the outside is turned off for the design. In this type of post-processing, the sprue preferably forms the maximum axial elevation at least on the respective diameter, so that a turning tool can be advanced during machining on the respective pass without an axial stroke dependent on the rotation angle. This enables quick and inexpensive turning.

It is also proposed in an advantageous embodiment of the cast wheel that a sprue is formed in the area of a spoke.

It is proposed here that the sprue is arranged in the area of a spoke of the cast wheel, this area of the spoke preferably being reworked, particularly preferably by means of gloss turning. A spoke usually represents a large, often the largest area on the outside of the cast wheel. Placing the sprue there offers the advantage mentioned above, that a faster or jam-free material guidance is made possible in the casting mold, whereby at the same time the sprue is formed on the spoke in an aesthetically effective manner, namely on the outside. Depending on the desired design, the sprue is unprocessed or reworked, or is (in some cases up to completely) removed in a (e.g. machining) rework. In an advantageous embodiment, the sprue, in that it is placed on the spoke, forms the maximum axial elevation (at least on the respective diameter), so that a cutting lifting of the or a part of the sprue (for example with a cast wheel rotating about the axis of rotation during machining) , as already described above with reference to a turning tool, can be carried out in a particularly simple manner.

It is further proposed in an advantageous embodiment of the cast wheel that the sprue is designed as a feeder, preferably as a blind feeder.

In this embodiment, the sprue is set up as a feeder so that shrinkage distortion and / or the formation of cavities in the area of the material of the cast wheel remaining in the final state is avoided by means of material retraction from the sprue. In this embodiment, at least that part of the sprue that is designed as a feeder is removed in a post-processing step. A material retraction does not always have to occur reliably, but rather only a tolerance range is used for these effects during the casting process. In a standardized ferti The sprue or the tolerance-related part of the riser is preferably removed in a post-processing process regardless of the actual use of the sprue as a feeder, preferably as described above. The tolerance-related feeder portion is that portion of the sprue so that the remainder, i.e. the remaining portion of the sprue (in the maximum case the remaining material of the cast wheel) is free of shrinkage and voids with maximum tolerance.

In a preferred embodiment, the sprue is designed as a blind feeder, that is, enclosed in the casting mold and not open to the outside.

According to a further aspect, a casting mold is proposed for a casting wheel according to an embodiment according to the above description, the at least one sprue being arranged in the casting mold only on the outside of the casting wheel to be formed as a primary molding,
wherein preferably one, particularly preferably single, casting aid is arranged centrally of the cast wheel to be formed as a primary molding, preferably on the outside of the cast wheel to be primary formed, and / or
wherein the inside is preferably cast without reworking.

A casting mold for a cast wheel as described above is proposed here, a casting mold being formed in several parts, for example four-part, so that, despite the required one-piece construction of the cast wheel and the necessary undercuts for mapping, no lost mold has to be used. The casting mold or parts of it are also referred to as a die and form the negative of the cast wheel to be formed. In an alternative embodiment, a lost shape or a die used in a few repetitions is used. The casting mold then comprises at least a part of the positive, which is first molded in a die, for example a sand casting device. For example, the casting mold can be used in a die-casting process.

The casting aid is preferably arranged centrally, for example in the wheel hub, as a feeder. In one embodiment, a single sprue aid is provided. The at least one sprue support preferably forms the only opening of the casting mold to the outside and is at the same time set up for introducing the casting material. This means that no further excess material to be removed occurs, apart from the at least one sprue, if this is to be removed again for aesthetic or mechanical (inertia) reasons. In one embodiment, the sprue aid is arranged in an area that the transition to the material of the cast wheel remaining in the final state can be removed by means of the same post-processing process as the (optional) removal of (at least a part) of the at least one sprue. The casting aid is then arranged on the outside, for example in an area that is gloss-turned in the final state. Alternatively, the casting aid is arranged on the inside, preferably in such a way that the transition to the material of the cast wheel remaining in the final state is never visible in use in a motor vehicle in normal use (i.e. in the assembled state even with a maximum steering angle). Alternatively, the inside can also be sufficiently reworked to meet aesthetic requirements.

In one embodiment, the inside of the casting wheel in the casting mold is formed without post-processing after the casting process has been completed. It is not excluded that at least one transition of a sprue aid remains visible on the inside, but is then arranged in such a way that the design of the cast wheel is not impaired. Alternatively, the sprue aid and each sprue that is to be removed again is arranged outside the inside, preferably only arranged on the outside. The rim mouth and the rim flanges and other components or areas of the cast wheel which are arranged outside the outside (preferably outside a reworked area of the outside) are preferably cast without reworking.

• - Aluminium;
• - Magnesium; und
• - Titan.

According to a further aspect, a production method is proposed for forming a cast wheel according to an embodiment according to the above description, wherein a casting mold according to an embodiment according to the above description is used,
wherein the casting material preferably comprises an alloy with at least one of the following materials:

• - aluminum;
• - magnesium; and
• - titanium.

The method proposed here is preferably carried out conventionally, the casting mold or the die being provided first (in a step a.) And then (in a step b.) The liquid casting material being introduced into the casting mold via the pouring aids. Finally, after sufficient cooling (in a step c.), The cast wheel (possibly also a cast blank) is removed from the mold and the casting aid (s) is at least partially removed from the outside of the now formed cast wheel. The area on the outside of the cast wheel is preferably reworked (in step d.), wherein step d. for example comprises a plurality of sub-steps, as described above, for example.

• 1: ein Gussrad in einer Außenansicht;
• 2: das Gussrad gemäß 1 in Schnittansicht A-A;
• 3: eine Gussform für ein Gussrad;
• 4: ein Kraftfahrzeug mit Gussrädern; und
• 5: Flussdiagramm eines Herstellverfahrens zum Bilden eines Gussrads.

The invention described above is explained in detail below against the relevant technical background with reference to the accompanying drawings, which show preferred embodiments. The invention is in no way restricted by the purely schematic drawings, it being noted that the drawings are not dimensionally accurate and are not suitable for defining size relationships. It is shown in

• 1 : a cast wheel in an external view;
• 2 : the cast wheel according to 1 in sectional view AA;
• 3 : a mold for a cast wheel;
• 4th : a motor vehicle with cast wheels; and
• 5 : A flow diagram of a manufacturing method for forming a cast wheel.

In 1 is a cast wheel 1 in an external view, so that the outside 5 of the cast wheel 1 is shown. The outside 5 is permanently visible in use of a motor vehicle 3, whereas the inside 4 (not visible here cf. 2 ) is aligned in use in a motor vehicle 3 to the wheel arch or to the other wheel of the respective (two-wheeled) vehicle axle (cf. 4th ). The axis of rotation 2 of the cast wheel 1 runs centrally balanced (as precisely as possible), for example through the hub bore 11, which is set up for connection to a wheel hub with wheel bearings (not shown here) and bores for wheel bolts 12, for example. Starting from the axis of rotation 2 in a rotationally symmetrical manner, spokes 7 (usually more than one and balanced with respect to the axis of rotation 2) span the cast wheel 1 and lead to a rim flange 13. It can now be seen here that the outside 5 of the cast wheel 1 is the sprue side, that is to say (optionally here) a plurality of sprues 6, namely one (single) sprue 6 per spoke 7. In the embodiment shown, the sprue 6 is arranged on all spokes 7 of the cast wheel 1, with the bordered area in which the indicative arrow of the respective sprue 6 is arranged being the reworked area or a sub-area of a reworked area, for example by turning. The respective spoke 7 is wider in the direction of rotation (around the axis of rotation 2 of the cast wheel 1), so that only the small triangles form an area free of material, i.e. a hole. In this embodiment, the spokes 7 are very wide and can therefore be made axially thinner for sufficient mechanical rigidity than would allow for reliable production of a cast wheel 1, at least taking into account the costs and technical feasibility (compare spoke 7 in the sectional view in FIG 2 ). The section line AA is marked vertically through the axis of rotation 2 and the corresponding sectional view is shown in FIG 2 shown.

In 2 the cast wheel 1 is shown in section AA 1 shown. The outside 5 of the cast wheel 1 is on the right-hand side of the picture and the inside 4 of the cast wheel 1 is on the left-hand side of the picture the axis of rotation 2 of the cast wheel 1. In this section AA, a spoke 7 of the cast wheel 1 is cut, on which the sprue 6 (in this case from the right) is formed on the outside 5 of the cast wheel 1. This sprue 6 is preferably subsequently removed, for example turned off, so that the spoke 7 remains only as an axially very thin web between the hub bore 11 and the rim mouth 14. Such a cast wheel 1 has sufficient mechanical rigidity and a low mass inertia. To avoid casting defects, the axial thickness (of the remaining portion) of the spoke 7 is insufficient and therefore a sprue 6, possibly as a feeder, preferably as a blind feeder (cf. 3 ) is added.

In 3 a casting mold 9 for a cast wheel 1 is shown. The structure of the cast wheel 1 corresponds, purely for the sake of clarity, to the illustration in FIG 1 and 2 so that reference is made to the previous description. To produce the cast wheel 1 shown, an outer molded part 15, an inner molded part 16, a first mouth molded part 17 and a second mouth molded part 18 are provided, with other shapes of cast wheels 1 also being producible in a casting mold 9 with any other molded parts. In the structure shown, the casting material is poured into the casting mold 9 from top to bottom, i.e. vertically, via a casting aid 10 into the cavity formed by the outer mold part 15, the inner mold part 16, the first mouth mold part 17 and the second mouth mold part 18 (here optionally in the Inner molded part 16) for the cast wheel 1 to be produced (preferably under pressure). The casting material is distributed in the cavity formed. The cavity preferably comprises more than the final state of the cast wheel 1 that is ready for use, namely additionally the sprue 6 shown on the later outer side 5 of the cast wheel 1. In this case, the sprue 6 is then removed again. In an alternative embodiment, the sprue 6 forms a desired design element, for example in the form of a single rib or a plurality of ribs. To remove the cast wheel 1 from the mold, the molded parts 15, 16, 17, 18 are separated from one another and one at This (optional) embodiment of the casting mold 9 inevitably formed in the casting aid 10 sprue (and optionally the sprue 6) removed.

In 4th a motor vehicle 3 is shown in a schematic plan view. In the area of the stern, a drive machine 8 is arranged, which is connected to propel the motor vehicle 3 in a torque-transmitting manner with (here two) propulsion wheels, for example cast wheels 1. In the area of the front of the motor vehicle 3, wheels (here for example two cast wheels 1) are also arranged for steering. For each cast wheel 1, the outside 5 is that side which faces away from the vehicle and is therefore visible to a person who is looking at the motor vehicle 3 from the side. The inside 4 of each cast wheel 1 is that side which points towards the motor vehicle 3, that is to say to the wheel arch or to the inside 4 of the opposite cast wheel 1 of the respective (two-wheeled) vehicle axle.

In 5 is shown a flowchart of a manufacturing method for forming a cast wheel 1. It is purely for the sake of clarity on the representation in the 3 Referenced. In one step a. the mold 9 is provided, and then in a step b. the liquid casting material is introduced into the casting mold 9 via the casting aids 10. Finally, after sufficient cooling in a step c. the casting wheel 1 is removed from the mold and, if necessary, the casting piece is removed from the casting aid 10. The outer side 5 of the cast wheel 1 is preferably used in a step d. post-processed, step d. for example comprises a plurality of sub-steps. For example, the outside 5 of the cast wheel 1 is in a step d1. gloss-turned and / or in a step d2. (before and / or after step d1.) painted.

The cast wheel proposed here meets the aesthetic requirements of the market, with the cast wheel being producible with a few reworking steps.

List of reference symbols

1

Cast wheel

2

Axis of rotation

3

Motor vehicle

4th

inside

5

Outside

6th

Sprue

7th

spoke

8th

Prime mover

9

mold

10

Sprue support

11th

Hub bore

12th

Wheel bolt

13th

Rim flange

14th

Rim mouth

15th

External molding

16

Interior molding

17th

first mouthpiece

18th

second shaped jaw part

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely 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

• US 5772801 A [0002]
• EP 3225335 A1 [0002]
• US 2014915243 A1 [0012]

Claims (7)

Cast wheel (1) with an axis of rotation (2) for a motor vehicle (3), having an inside (4) and an outside (5) visible in use in a motor vehicle (3), characterized in that the outside (5) has at least one Includes sprue (6). Cast wheel (1) after Claim 1 , the outside (5) being reworked, a sprue support (10) preferably being arranged on the outside. Cast wheel (1) after Claim 2 , the outer side (5) being turned off, preferably turned to a gloss finish. Cast wheel (1) according to one of the preceding claims, wherein a sprue (6) is formed in the region of a spoke (7). Cast wheel (1) according to one of the preceding claims, wherein the sprue (6) is designed as a feeder, preferably as a blind feeder. Casting mold (9) for a cast wheel (1) according to one of the Claims 1 until 5 , the at least one sprue (6) being arranged in the casting mold (9) only on the outside (5) of the cast wheel (1) to be formed as a primary forming, with preferably one, particularly preferably single, sprue support (10) central to the primary forming to be formed Cast wheel (1), preferably on the outside (5) of the cast wheel (1) to be formed in the original form, and / or with the inside (4) preferably being cast without post-processing. Manufacturing method for forming a cast wheel (1) according to one of the Claims 1 until 5 , with a mold (9) after Claim 6 is used, the casting material preferably comprising an alloy with at least one of the following materials: aluminum; - magnesium; and - titanium.

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