Patent Description:
Throttle control devices comprising a rotary grip associated with a handlebar of the vehicle of the type mentioned above have long been known. The rotation of the grip allows to change the number of revolutions of the engine of the vehicle ("throttle control") as a function of the needs and the use thereof.

An electronic throttle control device uses electric/electronic members functionally associated with the grip arranged on the handlebar which detects the rotation thereof and which controls the change in the number of revolutions of the engine of the vehicle as a function of said rotation. For example, such electric/electronic members comprise a first component integrally joined with the grip, usually defined by a rotor and a second component defined by a position or angular sensor, for example a Hall effect sensor, integrally joined with the handlebar or with a part proximal to the grip fixed thereto. The rotation of the grip entails the resulting rotation of the rotor, an event detected by the sensor and which, through a connection of the sensor to a control unit of the vehicle, results in the latter changing - in a per se known manner - the number of revolutions of the engine (for example by acting on a throttle-equipped body or a throttle valve).

Although such known devices operate satisfactorily, they do not offer riders the same sensations as the mechanical throttle control devices when the rider actuates the throttle control, that is rotates the grip for example to accelerate. Such sensation derives from a known radial clearance between the grip and the handlebar present in said mechanical devices, to which there corresponds the load of a spring of the throttle-equipped body or of the carburettor (defining the element for controlling the number of revolutions of the engine), and the friction of the first release friction and the sliding of the flexible mechanical drive system associated with the grip.

Such sensations cannot be detected when using the electronic throttle control where the coupling tolerances between the various components are very limited so as to avoid an incorrect control of the engine.

<CIT> describes a throttle control device used for controlling an engine of a vehicle based on the detection of a rotation angle of a rotary grip of the throttle rotatably mounted on a front end of a handlebar (h) of a vehicle. In the grip there is arranged a magnet which is rotatable integrally joined with the grip and an angular detector for detecting the changes of a magnetic field of the magnet in a non-contact fashion so as to detect the rotation angle of the grip. In the latter there is present a friction device for generating a resistant force during the rotation of the grip, said resistant force being variable. <CIT> is considered the closest prior art and discloses all of the features of the preamble of claim <NUM>.

In the grip there are present a first and a second spring, the first spring controlling the rotation of the grip so as to oppose it. The second spring is part of the friction device and it contributes to changing the resistant force of the latter, without acting on the rotation of the grip when it is used to change the number of revolutions of the engine of the vehicle.

An object of the present invention is to provide an electronic throttle control device for motorcycles, motorbikes, snowmobiles, personal watercrafts or similar vehicles, that is improved with respect to known electronic controls already available in the market.

In particular, an object of the present invention is to provide a throttle control device of the type mentioned above that offers the rider of the vehicle sensations substantially equivalent to those detected using a similar mechanical control device.

Another object of the present invention is to provide an electronic throttle control device that is quick to assemble and that is still cost-effective.

A further object of the present invention is to provide an electronic throttle control device which still offers high safety to the rider during use.

These and other objects which shall be more apparent to the person skilled in the art are attained by an electronic throttle control device according to the independent claim.

For a better understanding of the present invention, the following drawings are attached hereto, purely by way of non-limiting example, wherein:.

With reference to the aforementioned figures, they show two embodiments of a control device according to the invention. In all the figures, identical or corresponding parts are indicated using the same reference numerals.

Addressing <FIG>, they show, in the main components thereof, a control device <NUM> comprising a grip <NUM> adapted to be inserted into a handlebar (not shown) of a vehicle such as a four-wheeled motorcycle, a two or three-wheeled motorcycle, a snowmobile or a personal watercraft. In all these vehicles, the grip <NUM> is suitable to rotate around a longitudinal axis W thereof on the handlebar so as to allow to control throttle of the vehicle that is change the number of revolutions of the engine of the latter.

The grip <NUM> comprises an end <NUM> inserted into a box-like body <NUM> fixed to the handlebar and having two components <NUM> and <NUM> suitable to be enclosed into each other and which can be fixed to each other. More particularly, the end <NUM> of the grip <NUM> is inserted into a hole <NUM> of the component <NUM> of the box-like body <NUM> and it supports a chamber <NUM> into which there is inserted a common elastic element (compression spring) <NUM> whose function will be described below.

In the body <NUM> there is present a first torsion spring <NUM> (per se known), shown only in <FIG>, which has its mounting interface between the grip <NUM>, through the hole <NUM> and a special seat of the body <NUM> (not shown) so that - when assembled - it generates an established preload torque and suitable to define - upon the compression thereof - the effective arc of rotation (that is which generates the acceleration of the vehicle) of the grip and therefore the actual range of number of revolutions allowed to the engine of the vehicle (not shown).

The first torsion spring is fixed - at a first end 12A - to the chamber <NUM> and therefore to the grip and - at a second end 12B thereof - to the component mentioned above <NUM> being anchored to a pivot provided therein; such first spring <NUM> ensures feedback to the rider as regards the rotation obtained by the grip <NUM> and therefore the actual control of the throttle. The first spring <NUM> also and above all ensures a full return of the grip to the zero-acceleration position that is after the rider releases the control.

The chamber <NUM> protrudes radially from the end <NUM> of the grip and - upon rotating the latter around the axis W - it moves in a recess <NUM> of the component <NUM>. Such recess is proximal to a seat <NUM> for a second traction spring <NUM> having a preload different from that of the (first) spring <NUM> and operating on the grip <NUM> before the action of the first spring <NUM>. For example, the first spring has a preload comprised between <NUM> and <NUM>, while the second spring <NUM> has an equivalent torsion preload applied to the pipe comprised between <NUM> and <NUM>, that is such to generate a resistant torque on the grip <NUM> that is much lower than that of the first spring <NUM>.

Such second spring <NUM> has a first end <NUM> integrally joined with the chamber <NUM> of the grip <NUM> through a pivot <NUM> and a second end <NUM> fixed to a pivot <NUM> of the component <NUM>. It should be observed that the compression spring <NUM> has the function of ensuring that the mechanical stop element of the second traction spring <NUM> is held in position even in the presence of possible vibration loads coming from the vehicle.

Thanks to such second low preload spring <NUM>, when the rider rotates the grip <NUM> to accelerate, starting from a zero angular position that is with the grip fully rotated to end-stroke, said grip moves as if such second spring does not exist, therefore creating a sensation of initial "clearance" of the grip like in the case of mechanical throttle controls. Obviously, to such first "arc of rotation" or clearance does not correspond to any throttle control that is the engine of the vehicle does not increase the number of revolutions thereof, a control obtained by rotating the grip <NUM> counteracting against the first spring <NUM> which therefore acts "in a cascade fashion" that is subsequently to the action of the second spring <NUM>.

The rider therefore detects the clearance of the grip, but actually the latter, starting from the end-stroke position, rotates around the axis W counteracting against the second spring <NUM> which is also capable of counteracting the vibrations of the vehicle (generated by the running engine). Furthermore, the rider knows that he/she has to overcome the aforementioned clearance in order to accelerate and takes this into account when starting off, for example, the motorcycle in a race.

It should be observed that the initial rotation of the grip <NUM>, related to the presence of the second spring <NUM>, occurs for a very limited arc (for example smaller than <NUM>°, preferably from <NUM>° to <NUM>°), while the subsequent remaining rotation (which leads to the actual acceleration of the vehicle) occurs on a more significant arc, for example between <NUM>° and <NUM>°, counteracting the stiffness of the main compression spring <NUM> or first spring <NUM> (as it occurs in electronic controls, or Ride-By-Wire or RBW, standard) which acts on the grip <NUM> subsequently and immediately after the action of the second spring <NUM>.

Once the acceleration has terminated, the first spring <NUM> brings the grip to the position in which there is no increase in the number of revolutions of the engine and the second spring <NUM> returns the grip to the end-stroke (rotation angle equal to <NUM>°).

The invention also allows that a second characteristic generated by a mechanical control, be "felt" by the rider using the control device of the invention. Such characteristic is the first release and sliding friction of the flexible mechanical drive system (sheathed wire) which connects the grip to the throttle valve in mechanical throttle controls.

The aforementioned characteristic is "mimicked" by a rubbing of the second spring <NUM> against the curved shoulder <NUM> present in the box-like body <NUM>: in the embodiment of <FIG>, such shoulder <NUM> is integrally joined to the component <NUM> and it defines - therewith - the seat <NUM> for the second spring <NUM>. Thereon, there "extends" the second spring <NUM> when the rotation of the grip <NUM> starts and such second spring rubs thereon, with friction which is "felt" by the rider, when the grip <NUM> is rotated within the angular range in which it causes an increase in the revolutions of the engine (that is the acceleration thereof).

It should be observed that such shoulder <NUM> protrudes from a portion 7A of the first component <NUM> and it comprises a vacant end 27A folded towards the first component <NUM> that is towards the end <NUM> of the grip <NUM>, that is the aforementioned shoulder <NUM> is not concentric to the hole <NUM> in which such end <NUM> is inserted, but "points" towards it. This allows the initial rotation of the grip <NUM> (starting from the end-stroke thereof) around the axis W without risks of breaking the second spring <NUM> due to an excessive pressure on the shoulder <NUM>; however, at the same time there is generated a relative sliding between the second spring <NUM> and the aforementioned shoulder such to create a resistance against the rotation of the grip <NUM>, a resistance which reminds of the sliding of the flexible mechanical drive system of the mechanical throttle control devices.

The aforementioned solutions allow the rider to have the sensation (usually positive since it offers greater confidence in riding the vehicle) of riding a motorcycle or the like using a mechanical throttle control device and is not affected by the "joystick effect" which are often offered by electric throttle control devices (RBW).

<FIG> also show part of the components (associated with the body <NUM>) suitable to allow the electric control (RBW) of the engine and that is the components indicated with <NUM>, per se known and therefore not described. Such components comprise detection means (per se known and not described further) suitable to detect the rotation of the grip and - as a result - control the number of revolutions of the engine of the vehicle.

<FIG> show a different embodiment of the invention. In this solution, the second spring <NUM> (associated through a first end <NUM> to a member <NUM> for constraining to the chamber <NUM> integrally joined with the grip) is connected - with a second end <NUM> thereof - to a metal wire <NUM> (dashed in the figures) arranged in a sheath <NUM>, for example made of rubber, in turn arranged in a corresponding seat <NUM> of at least one of the components <NUM> and <NUM> of the body <NUM> (it is obtained in the first component <NUM> in the figures).

The metal wire <NUM> has a first end <NUM> fixed - at the second end <NUM> of the second spring - to a second end <NUM> fixed to the component <NUM>.

The sheath <NUM> and the wire are arranged, curved, in the body <NUM> around the hole <NUM> of the component <NUM> of such body.

When the rider accelerates, after a first rotation (starting from the end-stroke) of the grip in which the second spring <NUM> is pulled creating the clearance (or "idle stroke") described above relating to <FIG>, the grip actually causes - by rotating it - the acceleration of the engine. After the initial arc (for example between <NUM>° and <NUM>°), the rotation of the grip drives the wire <NUM> in the sheath <NUM> (due to the traction of the second spring <NUM> integrally joined with such wire) and this generates a friction of the wire in the sheath offering the rider the sensation that it can cause when riding a motorcycle using a mechanical throttle control device.

Therefore, even the solution of <FIG> allows to obtain an electric throttle control device <NUM> of the RBW type, which mimics a similar mechanical device.

Claim 1:
Electronic throttle control device for a two or three-wheeled motorcycle, a four-wheeled motorcycle, a snowmobile or a personal watercraft, the vehicle having a handlebar on which there is mounted a grip (<NUM>) of said control device (<NUM>), under the action of a rider, the grip (<NUM>) being suitable to rotate around a longitudinal axis (W) thereof starting from an end-stroke position to change the motion condition of the vehicle, said rotation being detected by detection means (<NUM>) suitable to allow throttle control that is change the number of revolutions of an engine of the vehicle as a function of a rotation of the grip (<NUM>), the grip (<NUM>) being associated with a body (<NUM>) fixed to the handlebar and rotating with respect thereto, there being provided for a first spring (<NUM>) with preestablished preload which allows the rotation of the grip (<NUM>) on a predetermined arc of rotation corresponding to a range of possible number of rotations for the engine, wherein there is provided for a second spring (<NUM>) operating on the grip (<NUM>) at the start of the rotation thereof from the end-stroke around the longitudinal axis (W) in the same rotational direction, said second spring (<NUM>) having a preload lower than that of the first spring (<NUM>) and acting on the grip (<NUM>) before the range of said first spring (<NUM>) on the grip, such action of the second spring (<NUM>) generating the perception - in the rider - of an initial clearance in the rotation of the grip (<NUM>) and not causing any increase of the number of revolutions of the engine, said clearance corresponding to a clearance of a mechanical throttle control device, characterised in that first and second spring (<NUM>, <NUM>) returning the grip (<NUM>) to the same end-stroke position at the end of the change of the motion condition of the vehicle.