Patent Application
20090255365
The present invention relates to dampening mechanical vibrations in a motorcycle. A motorcycle can experience mechanical vibrations from a variety of sources. The vibrations can have adverse effects on a rider including discomfort, and, if subjected to the vibrations for an extended period of time, soreness. Many conventional dampening systems include heavy tuned masses mounted to an end of a handlebar of the motorcycle.
The present invention provides a motorcycle rider interface that includes a surface and a vibration dampening assembly. The vibration dampening assembly is affixed to the surface of the rider interface and includes a piezoelectric element and a load element. The piezoelectric element produces an electrical energy in response to a strain on the rider interface. The load element is electrically connected to the piezoelectric element such that the vibration dampening assembly dampens vibrations of the rider interface.
In another aspect, the present invention provides a method of dampening a vibration in a motorcycle. The method includes affixing a vibration dampening assembly to a surface of a rider interface and electrically connecting a load to the vibration dampening assembly. The vibration dampening assembly including a piezoelectric element. The method also includes converting a strain on the vibration dampening assembly to an electrical signal, which is dissipated by the load to dampen the vibration.
Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings.
Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms “mounted,” “connected,” “supported,” and “coupled” and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings.
The vibrations experienced by the motorcycle 10 also are manifested in different areas. For example, an exhaust pipe of the motorcycle 10 or handlebar 22, in many instances, experience significant mechanical vibrations. The vibrations experienced at the handlebar 22 are particularly important, as the handlebar 22 is a primary contact point between a rider and the motorcycle 10. Embodiments of the invention include ways of reducing the mechanical vibrations experienced at the handlebar 22. In other embodiments, mechanical vibrations are reduced at different rider interfaces, such as a seat, a console, a pedal, a foot peg, a floor board, or the like.
The amount of vibration dampened by the vibration dampening assemblies 32, if implemented inefficiently, may only be a small percentage of the strain applied to the handlebar 22. As discussed above, the degree to which mechanical vibrations in the handlebar 22 are dampened depends on the size and location of the vibration dampening assemblies 32. The effectiveness of the vibration dampening assemblies 32 is also influenced by their location within the handlebar 22, as well as how the assemblies 32 are coupled to the handlebar 22. The vibration dampening assemblies 32 are advantageously placed at locations within the handlebar 22 that experience the most strain, and therefore, cause the vibration dampening assemblies 32 to dissipate the greatest amount of energy. The placement of the vibration dampening assemblies 32 varies with factors such as the type of motorcycle, the size of the engine, the shape of the handlebar, and the like. For example, in some embodiments, the vibration dampening assemblies 32 are placed at extremities of the handlebar 22 or at bends and joints of the handlebar 22. Additionally, as shown in
In some embodiments, the load 42 attached to the element 36 is a passive load. For example, the load 42 may be a resistor having first and second leads 38 and 40. The voltage that is generated across the element 36 is then dissipated by the resistor 42 in the form of heat. The voltage generated across the element 36 is a product of the vibrational frequency of the handlebar 22. A purely resistive passive load is able to dissipate a wide range of voltages and pass a wide range of currents. Therefore, the purely resistive passive load functions as an adaptive vibration dampening device capable of dampening a wide range of vibrational frequencies experienced by the handlebar 22. The voltage generated across the element 36 also depends on the type, size, and number of the piezoelectric elements 36 in the assembly 32. Accordingly, resistance values for the load 42 are selected to account for the variance in generated voltages.
As illustrated in
In some embodiments of the invention, the voltage generated by the elements 36 is used to provide a signal to a rider related to the vibration dampened by the assembly, as illustrated in
In another embodiment, the energy generated by the elements 36 is used to charge a battery, as illustrated in
In some embodiments, the electrical loads 50-64 are configured such that, when placed across one or more of the piezoelectric elements 36, the electrical properties of the loads 50-64 (i.e. capacitance, resistance, and inductance, etc.) form a filter or resonant circuit at a respective frequency. The resonant circuits operate to enhance and more efficiently dissipate energy from the piezoelectric elements 36 at a respective frequency. In some embodiments, the loads include, for example, a resistor, a capacitor, and an inductor to form a resistor-inductor-capacitor (RLC) network. The RLC network's resistor, capacitor, and inductor values are chosen based on a predetermined vibrational frequency to be dampened. For example, in many instances, a motorcycle 10 has a natural frequency at which it produces a significant mechanical vibration. In addition to the natural frequency, dynamic factors such as an engine's rotations per minute (RPM), which constantly change during the normal course of operation, contribute to the amount and degree of mechanical vibration a rider experiences. In one embodiment, each electrical load 50-64 is at a different resonant value. For example, the piezoelectric elements 36 can include a first electrical load effective at a lower resonant value, and a second electrical load effective at a higher resonant value. For example, a motorcycle 10 having an engine idle of 7000 RPM could include a filter effective at a resonant value of 117 Hertz (7000 RPM/60 seconds=117 Hertz). Other embodiments include additional loads at different resonant values.
In additional embodiments, at least one of the vibration dampening assemblies 32 is an active dampening system. In contrast to the passive system, the active system applies a voltage to the piezoelectric elements 36. For example, as illustrated in
In other embodiments, the applied voltage is proportional to a condition of the motorcycle 10. For example, the controller 50 is connected to an on-board computer that includes information related to one or more of current motorcycle conditions. The controller 50 is programmed to accept signals from the on-board computer related to the conditions. The controller 50 recognizes the condition and outputs a signal necessary to effectively dampen the vibration. For example, the current motorcycle conditions can include conditions such as speed and RPM. In many instances, the most prominent cause of mechanical vibration experienced by the handlebar 22 is the RPM of the engine 18. As the RPM of the engine 18 changes, the frequency and amplitude of the vibration experienced at the handlebar 22 can change. The controller 50 is configured to continuously accept the signals and adjust its output to the active piezoelectric elements 36. In some embodiments, the output of the controller 50 is amplified or phase shifted in order to more effectively dampen vibrations. In other embodiments, the controller 50 saves previous signals related to a first condition of the motorcycle 10 and establishes an output set point for the first condition. The output set point is a value for the first condition of the motorcycle 10 that most effectively dampens the vibration. The output set point can be constantly adjusted by the controller 50. The output set point and a current output value related to the first condition of the motorcycle 10 are then used in a feedback mechanism, such as, for example, a proportional-integral-derivative controller (PID controller) to output a corrective signal to dampen the vibration.
In additional embodiments of the invention, vibration dampening assemblies are incorporated into different portions of the motorcycle 10, for example, in a steering apparatus, as well as into other vehicles such as bicycles, boats, planes, trains, automobiles, all-terrain vehicles, snowmobiles, and the like to dampen vibrations experienced by a rider or passenger.
Thus, the invention provides, among other things, systems and methods for dampening mechanical vibrations in a handlebar. Various features and advantages of the invention are set forth in the following claims.
