Patent Application
20240174038
The present application claims priority of European Application Number 22210563.7 filed Nov. 30, 2022, the disclosure of which is hereby incorporated by reference herein in its entirety.
The present disclosure relates to a chassis component and to a method for producing a chassis component.
Chassis components, which guide and stabilize the wheel suspension connected to a wheel of the motor vehicle, are mechanically connected to the wheel suspension and the chassis of the motor vehicle. Such a chassis component is a spring link. In order to be able to precisely adjust and align corresponding chassis components during assembly and, for example, to adjust the toe or camber of the wheels of the motor vehicle, the mechanical connection is able to be provided via an eccentric mechanism.
Chassis components with a corresponding eccentric mechanism have an opening and two guide elements arranged on opposite sides of the opening for guiding an eccentric element. The eccentric element is formed from an eccentric disk or eccentric screw, which have a collar which is arranged eccentrically with respect to the axis of rotation of the eccentric element. The collar of the eccentric element is in contact with the guide elements. The opening in the chassis component is able to be designed as an elongated hole, so that the chassis component, e.g., the spring link, is moved further towards the outside of the vehicle or towards the inside of the vehicle by the guide elements when the eccentric element rotates.
Corresponding eccentric arrangements are described in U.S. Pat. No. 11,338,635 B2, which describes a multi-leg link for a wheel suspension in a vehicle, wherein an eccentric disk of a corresponding eccentric mechanism is designed to rest on guide elements in order to guide the link with respect to an axle carrier and/or wheel carrier when the eccentric disk rotates and thus determine the steering camber and/or toe. The guide elements are formed in one piece with the material of a link arm and have a rectangular shape with rounded ends. Due to the shape of the guide elements, high pressure is required for the forming process. Due to the high pressure, the forming process leaves pinch joints or other damage on the component, which reduces the service life of the chassis component.
U.S. Pat. No. 11,260,715 B2 also describes a corresponding eccentric mechanism with guide elements. The guide elements in said patent are slotted using cutting technology, which is able to have a negative effect on the service life of the component and increases the risk of cracks forming within the guide elements.
The object of the present disclosure is to provide a chassis component with guide elements which achieves a longer service life and is inexpensive to produce.
A further object of the present disclosure is to provide a method for producing a corresponding chassis component.
The aforementioned object is achieved according to the disclosure with a chassis component.
The method part of the object is further achieved with a method for producing a chassis component. The chassis component according to the disclosure, which is able to be a wishbone or a spring link in some embodiments, has a base body, wherein the base body is a link arm of the spring link. The base body also has an opening for passing through a fastening means. Two guide elements for guiding an eccentric element are arranged on the opposite sides of the opening. The guide elements are formed in one piece and using the same material of the base body of the chassis component by mechanical processing. This configuration makes provides for easy and cost-effective production of the guide elements, since no separate component is required and the guide elements are formed in a simple manner by the material of the chassis component. Due to the one-piece design and material unity, additional fastening of the guide elements is not necessary. This is able to prevent them from slipping or coming loose in the finished chassis component, as would be possible if a separate component was used. This significantly increases the service life of the component and permanently ensures the adjustment for toe and/or camber.
The guide elements each have a back side and a contact side facing the opening. The contact side is aligned orthogonally to the base body. The guide elements come into contact with the eccentric element via the contact sides and thus ensure a displacement of the chassis component due to a corresponding rotation of the eccentric element. When the eccentric element rotates, a force is transmitted to the guide elements via the contact sides.
In at least one embodiment of the disclosure, an outer transition region with a radius is formed between the respective contact sides and the base body. Due to the force transmitted by the eccentric elements, the guide elements are subjected to a high load. This load often results in crack formation, which is able to occur at the transition point between the contact side and the base body. The service life of the chassis component is therefore reduced. The transition region according to the disclosure between the contact sides and the base body initially increases the material thickness in this critical region. Surprisingly, the formation of the transition region with a radius has also been shown according to the disclosure, which connects the contact sides to the base body, significantly reduces the risk of crack formation. This increases the service life of the chassis component. The thus formed radius also ensures a secure fit between the contact side and the eccentric element. In addition, the shape of the transition region according to the disclosure is suitable for cost-effective production of the chassis component by shifting the material of the chassis component from the base body.
The radius of the outer transition region according to the disclosure is able to be between 0.2 mm and 2 mm, and 0.5 mm and 1.5 mm. Appropriate dimensioning has proven to be advantageous for the stability of the guide elements.
The back sides of the guide elements taper in the opposite direction to the contact sides and merge into the base body. This has several advantages. Due to the tapering of the back sides and the transition into the base body, the guide elements are able to be designed to save a lot of space. The guide elements are able to occupy a total area on the base body of less than 20 mm2, between 4 and 18 mm2, between 6 and 15 mm2. Surprisingly, this shape of the guide elements counteracts material fatigue despite the small area has been shown. Due to the shape of the guide elements, the grain flow of the material is not interrupted, which is able to lead to a low tendency for crack formation. Due to the material uniformity in the tapering of the back sides with a corresponding transition into the base body, the guide elements are also extremely robust. The force transmitted by the eccentric element is able to be transferred very well to the base body due to the shape of the guide elements. The shape of the guide elements is also suitable for cost-effective production of the chassis component by shifting the material of the chassis component from the base body.
The contact sides have a plano-convex shape. The plano-convex shape of the contact sides, which are aligned orthogonally to the base body, forms an optimal contact for the eccentric element and prevents the eccentric element from slipping.
Alternatively, the side of the contact side facing away from the base body is able to have an at least partially flattened region which runs parallel to the base body. In this way, the height of the contact sides and thus the height of the guide elements is able to be made as low as possible without reducing the contact surface for the eccentric element. The flattened region is able to be completely flat, or less curved, so that an overall flatter contact surface results than with a plano-convex design of the contact side.
The base body has an indentation below the guide elements. The indentation has a front side and a top side, the front side being arranged parallel to the contact side. A corresponding indentation is formed by the manufacturing process of the guide elements, since the material of the base body is displaced to the outside, for example by a punch. In the context of the disclosure, a parallel alignment of the front side with the contact side leads to increased stability between the guide elements and the base body, which has an advantageous effect on the energy flow and the service life of the chassis component.
An inner transition region with a radius is arranged between the front and the top side. The transition region increases the stability of the guide elements and reduces the risk of cracks at the contact point between the front and the top.
The base body has an underside in the region of the opening. A lower transition region with a radius can be formed between the front and the bottom. The chassis component can be designed in such a way that the inner transition region merges directly into the lower transition region. In this case, no separate front side is formed between the transition regions.
An orthogonal distance is formed between the parallel front side and contact side, which corresponds to between 10% and 50% of the material thickness of the base body. This ensures sufficient material thickness between the contact side and the front side, so that there is sufficient stability of the guide elements. At the same time, the distance according to the disclosure between the front side and the contact side provides an optimal shape or size of the guide elements. The distance corresponds to between 20% and 40% of the material thickness of the base body and between 25% and 35% of the material thickness of the base body.
A distance between the outer transition region and the inner transition region is provided in a central vertical cross section of the guide elements, which corresponds to between 30% and 80% of the material thickness of the base body. This is the shortest distance between the inner transition region and the outer transition region. In some embodiments of the disclosure, this distance provides a high level of robustness and service life of the guide elements. A distance according to the disclosure leads to a stable material structure with a low risk of cracks. The grain flow of the material is not interrupted by the distance according to the disclosure between the transition regions. The distance is between 40% and 60% of the material thickness of the base body and between 45% and 55% of the material thickness of the base body. This distance is additionally largely determined by the presence of the radius of the outer transition region according to the disclosure and the radius of the inner transition region.
In at least one embodiment of the present disclosure, the chassis component is made of a light metal material, for example an aluminum alloy. This reduces the weight of the chassis component, which has an advantageous effect on the driving characteristics and fuel consumption of the motor vehicle.
The chassis component is an extruded profile. Chassis components with complex and irregular shapes are also able to be manufactured.
The guide elements are cold-formed. This enables short processing times, good surface quality, tight dimensional tolerances, optimal material utilization and long-term consolidation of the material. The grain flow of the material is also not interrupted. Cold forming maintains the continuous structure of the material without any tendency for crack formation. Due to the displacement or shift of material instead of an incision and the associated essentially uninterrupted grain flow, a cut-related breakage in the contact side is avoided and the risk of cracks forming and growing when producing the chassis component, especially during its service life, is reduced.
In at least one embodiment of the present disclosure, the contact sides have a height that is less than or equal to the material thickness of the base body. Since the guide elements are formed in one piece and with the same material of the base body of the chassis component, this ensures that the material thickness of the guide elements is sufficient for the load caused by the eccentric element.
The opening in the base body of the chassis component is an elongated hole. A corresponding elongated hole allows the chassis component to be displaced relative to the eccentric element. The method according to the disclosure for producing a chassis component comprises the following steps:
The chassis component precursor is a wishbone, or a spring link.
In at least one embodiment of the present disclosure, the chassis component has two opposing spring arms, each with a base body, wherein both base bodies being simultaneously provided with corresponding guide elements during the forming process.
In at least one embodiment of the present disclosure, the chassis component precursor is made of an aluminum alloy and is an extruded profile.
In at least one embodiment of the present disclosure, the base body already has an opening for passing through a fastening means, so that the guide elements are able to be formed on opposite sides of the opening for guiding an eccentric element.
Alternatively, an opening for passing through a fastening means is able to be formed in the base body simultaneously with the guide elements, wherein the guide elements are also in this case arranged on opposite sides of the opening. In this embodiment variant, two forming steps are able to be carried out in one, which speeds up the manufacturing process.
The guide elements are formed using a cold forming process. This enables short processing times, good surface quality, tight dimensional tolerances, optimal material utilization and long-term consolidation of the material. The grain flow of the material is also not interrupted. Initially the base body is inserted into the forming tool so that the base body rests on the lower die. The base body is fixed on the lower die by the fixing element. In a next step, the guide elements are formed by linearly advancing the punch. To do this, the punch presses the material of the base body into the corresponding mold recesses. Due to the oblique alignment of the punch to the base body according to the disclosure, only a small amount of pressure is required compared to conventional manufacturing processes. The force is between 5 t and 20 t, or between 7.5 t and 13 t. The lower pressure is able to save energy costs. In addition, both the forming tool and the chassis component precursor are subjected to less stress. In addition, due to the low pressure, the material of the base body is not damaged by the forming tool, so that no weak points remain in the material. The oblique orientation of the punch also leads to an advantageous grain flow within the material, which enables the guide elements to be highly robust. There is only an extremely low risk of cracks at the transition between the base body and the guide element. Furthermore, no cutting of the material is required, which also improves the robustness and strength of the guide elements according to the disclosure.
The punch head is designed in such a way that, as a result of the forming process, the contact sides of the guide elements have a plano-convex shape and the back sides taper in the opposite direction to the contact sides and merge into the base body. The mold recesses of the lower die are also designed accordingly.
In at least one embodiment of the present disclosure, the punch head is designed in such a way that by the forming process an inner transition region with a radius is formed between the front side and the top side. The mold recesses of the lower die are designed in such a way that by the forming process an outer transition region with a radius is formed between the contact side and the base body.
The surfaces of the guide elements are able to be polished after the forming process. This additionally increases the service life of the chassis component.
The invention disclosure is described in more detail hereinafter on the basis of exemplary embodiments illustrated in the drawings. In the figures:
In the figures, the same reference numbers are used for same or similar components, even if a repeated description is omitted for reasons of simplicity.
The eccentric element 5 has an eccentric screw 8 with an outer collar 9. The outer collar 9 of the eccentric element 5 is guided by the guide elements 4 in such a way that when the eccentric element 5 rotates, the eccentric screw 8 moves within the opening 3 and the chassis component 1 is thus displaced.
According to the perspective view of the chassis component 1 in
The guide elements 4 in section A-A of
The radius Ra is between 0.2 mm and 2 mm, between 0.5 mm and 1.5 mm.
The base body 2 has a respective indentation 12 below the guide elements 4, as seen in
An orthogonal distance is formed between the parallel front side 13 and contact side 7, which corresponds to between 10% and 50% of the material thickness Sg of the base body 2. The distance A is between 20% and 40% and between 25% and 35% of the material thickness Sg of the base body 2. This distance A according to the disclosure ensures sufficient material thickness between the front side 13 and the contact side 7, which increases robustness and lifespan of the guide elements 4.
An inner transition region 15 with a radius Ri is able to be arranged between the front side 13 and the top side 14. The inner transition region 15 increases the stability of the guide elements 4 and also reduces the risk of cracks at the transition between the front side 13 and the top side 14.
The middle vertical cross section of the guide elements 4, as shown in section A-A of
The base body 2 has an underside 16 in the region of the opening 3. A lower transition region 17 with a radius is able to be formed between the front side 13 and the underside 16.
In an alternative embodiment variant, the chassis component 1 is able to be designed such that the inner transition region 15 merges directly into the lower transition region 17. In this case, no separate front side 13 is formed between the transition regions 15, 17.
The chassis component 1 is made of an aluminum alloy and is an extruded profile.
The guide elements 4 are cold formed. This enables short processing times, good surface quality, tight dimensional tolerances, optimal material utilization and long-term consolidation of the material. The grain flow of the material is also not interrupted.
As shown in
Due to the angle α according to the disclosure between the punch 20 and the base body 2, only a small amount of pressure is required to form the guide elements 4. The pressure for the forming process is between 5 t and 20 t, between 7.5 t and 13 t. In comparison to similar forming processes for producing guide elements 4, this involves extremely low pressure. On the one hand, this has the advantage that less energy is required for the forming process, and on the other hand, due to the low contact pressure, there are no unwanted indentations or other damage to the base body 2 that originate from the forming tool 19. The oblique orientation of the punch 20 also makes possible to obtain with the forming process a material structure that is optimal for the stability of the guide elements 4. The material fibers are preserved so that the material structure and thus the robustness and strength of the material are not affected.
The punch 20 has a punch head 24. The punch head is designed in such a way that, as a result of the forming process, the contact sides 7 of the guide elements 4 have a plano-convex shape and the back sides 6 taper in the opposite direction to the contact sides 7 and merge into the base body 2. The mold recesses 23 of the lower die 21 are also designed accordingly.
In at least one embodiment of the present disclosure, the punch head 24 is designed in such a way that by the forming process an inner transition region 15 with a radius Ri is formed between the front side 13 and the top side 14. The mold recesses 23 of the lower die 21 are designed in such a way that by the forming process an outer transition region 11 with a radius Ra is formed between the contact side 7 and the base body 2.
In at least one embodiment of the present disclosure, the base body 2 has an opening 3 for passing through a fastening means, so that the guide elements 4 are able to be formed on opposite sides of the opening 3 for guiding an eccentric element 5.
Alternatively, an opening 3 for passing through a fastening means is able to be formed in the base body 2 at the same time as the guide elements 4. Here too, the guide elements 4 are arranged on opposite sides of the opening 3. By simultaneously forming the opening 3 and guide elements 4, two processing steps of the production process are able to be merged, which has an advantageous effect on the processing time of the chassis component precursor 18.
The guide elements 4 are formed using a cold forming process. This enables short processing times, good surface quality, tight dimensional tolerances, optimal material utilization and long-term consolidation of the material. The grain flow of the material is also not interrupted.
In at least one embodiment of the present disclosure, the surfaces of the guide elements 4 are additionally polished after the forming process. This further increases the service life of the chassis component 1.
| Number | Date | Country | Kind |
|---|---|---|---|
| 22210563.7 | Nov 2022 | EP | regional |
