DE-102024203041-B4 - spring pad, suspension element and motor vehicle

Abstract

Spring support (14) for a suspension element of a motor vehicle (2), wherein the spring support (14) - an electroactive polymer and - has a piezoactive element (22).

Inventors

• Heino Meinen
• Daniel Diekmann

Assignees

• VOLKSWAGEN AKTIENGESELLSCHAFT

Dates

Publication Date

20260513

Application Date

20240403

Claims (10)

1. Spring support (14) for a suspension element of a motor vehicle (2), wherein the spring support (14) comprises - an electroactive polymer and - a piezoactive element (22).
2. Spring pad (14) according to one of the preceding claims, wherein the electroactive polymer is a dielectric elastomer.
3. Spring support (14) according to one of the preceding claims, wherein the piezoactive element (22) is arranged adjacent to the electroactive polymer along a load direction of the spring support (14).
4. Spring support (14) according to one of the preceding claims, wherein the spring support (14) is designed such that a load on the spring support (14) along a load direction causes a change in the overall stiffness of the spring support (14).
5. Spring support (14) according to one of the preceding claims, wherein the electroactive polymer comprises an elastomer film, and wherein electrodes (30, 32) are arranged on opposite sides of the elastomer film.
6. Spring support (14) according to one of the preceding claims, wherein the spring support (14) has a layered structure.
7. spring pad (14) after Claim 6 , wherein the spring support (14) has a first protective layer, (24) a first electrode layer (26), a polymer layer (28), a second electrode layer (30) and a second protective layer (32) along a load direction.
8. Spring pad (14) according to one of the preceding claims, wherein the spring pad (14) comprises a non-electroactive polymer in addition to the electroactive polymer.
9. Suspension element with at least one spring pad (14) according to one of the Claims 1 until 8 .
10. motor vehicle (2) with a spring pad (14) according to one of the Claims 1 until 8 or with a suspension element according to Claim 9 .

Description

The invention relates to a spring support for a suspension element of a motor vehicle, a suspension element and a motor vehicle. To achieve desired driving characteristics and a comfortable ride, the axles of a motor vehicle absolutely require the installation of springs and dampers to stabilize the vehicle body against road vibrations. Accordingly, suspension elements for motor vehicles, which are usually combined with a damping system, have been known for a long time. In practice, the spring element is typically a coiled steel wire spring mounted at the top and bottom on an elastic element, which can be called a spring pad or spring support. These elements usually consist of a natural rubber-based elastomer and are manufactured as molded rubber parts. The purpose of these elements is, on the one hand, to provide support for the spring and, on the other hand, to offer isolation for acoustic decoupling. Nevertheless, in the high-frequency range (>100 Hz) and at small amplitudes (<0.5 mm), short-term resonance vibrations can occur during transient processes, which can manifest, for example, as a so-called "noise-ping" when the vehicle door is slammed. Technically, these vibrations are irrelevant, but can lead to an acoustically inferior impression, as they occur in the high-frequency range. The WO 2014 / 106 607 A1 This document describes a chassis device with at least one wheel suspension, which includes at least one shock absorber and at least one longitudinal extension of the wheel suspension oriented at least substantially parallel to a longitudinal direction of the shock absorber. Furthermore, the chassis device includes at least one chassis element designed to change the longitudinal extension of the wheel suspension in at least one operating state. It is proposed that the chassis element incorporate at least one smart material. This document refers to a wheel suspension and its integration into a shock absorber or strut. The core of the teaching is a "change in the longitudinal extension of the wheel suspension during operation," which, in certain embodiments, but not exclusively, is caused by an electroactive material or an elastomer as a result of a stimulus, for example, by applying an electric field. From the EP 2 172 352 A1 A motor vehicle suspension spring is known which is equipped at its ends with an active spring pad. The spring pad consists of a lower part, an upper part, and a piezo actuator arranged between them. To increase the frequency range of a dampable spectrum, the piezo actuator can be appropriately controlled, for example, with a phase shift, by means of an electrical voltage. The WO 2012 / 120 009 A1 This describes a layered composite comprising at least one piezoelectric layer and one dielectric elastomer layer sandwiched between electrically conductive layers. This hybrid layered composite combines sensor, actuator, and energy harvesting functions in a compact unit, with the piezoelectric layers converting mechanical energy into electrical energy and the dielectric elastomer layers being used for actuator applications. Cascading multiple layers maximizes energy yield, while the multifunctional structure enables broad applicability. The known spring pads according to the prior art are either limited with regard to the possible frequency spectrum or require complex active control, in which an electrical voltage or electric field must be applied to achieve a desired effect. This also requires sensors connected to the control system to determine state variables to which a short-term reaction is then required. It is therefore the object of the present invention to provide a simple way to avoid unwanted frequencies, in particular so-called “noise pings”, during the operation of a motor vehicle. The problem is solved by a spring pad of the type mentioned above, wherein the spring pad comprises an electroactive polymer and a piezoactive element. The problem is further solved by a suspension element with such a spring pad, and by a motor vehicle with at least one such spring pad or with such a suspension element. This makes it possible to create a self-regulating system that automatically reacts to a stimulus in the form of a mechanical vibration and thereby changes the stiffness of the spring pad. According to the invention, the spring pad is constructed such that it consists wholly or partially, for example in segments, of an electroactive element, for example a dielectric elastomer, and a piezoactive element, in particular a piezo-sensor element, is integrated into it. A piezoactive element A piezoelectric element, in particular, is understood to be a component or element that utilizes the piezoelectric effect to produce an electrical voltage when a mechanical force is applied. The vibration of the spring exerts mechanical pressure on the spring pad. Due to the integration of the piezoelectric element into the spring pad, this mechanical pressure also acts on the piezoelectric elemen