STEERING WHEEL RIM WITH INTEGRATED SWITCH DEVICE

This invention relates to steering wheels, for example steering wheels used in vehicles such as cars, and in games consoles, simulator devices and boats.

Steering wheels are fitted with an ever-increasing number of buttons for easy access control of items such as in-car audio. As the steering wheel turns, the buttons generally move with the wheel. In some vehicles, finger operated paddles behind the steering wheel are used for gearshifts. The paddles can be fixed or rotate with the steering wheel.

If the paddles are fixed, during wheel rotation the driver's fingers may not be able to reach the paddles. If they rotate with the wheel, the driver may have difficulty locating them during spirited driving.

More recently cars have been manufactured with the central portion of the steering wheel fixed and non-rotating. This provides a space for buttons that do not move when the steering wheel is rotated. This requires the driver to remove a hand from the steering wheel in order to operate the buttons.

It is also known to include a twist grip within the structure of the steering wheel to enable the user to perform a switching operation to control braking and acceleration and to include buttons on the rim of the steering wheel to make gear changes, for example see US2002/0104705. Each twist grip is mounted on a rectilinear axle that forms part of the structure of the steering wheel. Thus the steering wheel does not have a continuous structure. Furthermore, the driver is only able to actuate the twist grips in specific designated areas of the steering wheel since each twist grip rotates about a rectilinear axis. This can cause problems if the driver wants to operate the switch devices when turning the steering wheel since he has to change the position of his hands when turning.

An object of the invention is to mitigate at least one of the above-mentioned problems, or at least to provide an alternative arrangement of steering wheel mounted controls.

According to one aspect of the invention there is provided a steering wheel including a substantially annular steering member and a switch device provided on the substantially annular

steering member, wherein the switch device is operable by actuating at least one switch element comprising at least a portion of the substantially annular steering member, wherein the switch device extends around substantially the entire annular steering member.

It is to be understood that the term "extends around substantially the entire annular steering member" means that the switch device is operable around substantially the entire steering member, and includes arrangements having a plurality of switch elements that are separated by gaps, for example to accommodate spokes in a steering wheel, or a single arcuate switch element extending less than 360 degrees. Typically the gaps should be smaller than the width of the driver's hand so that the switch device is operable around the entire steering wheel, for example the total gap size is preferably less than 90 degrees so that the switch element or the plurality of switch elements extend around at least 270 degrees of the steering member. This enables the user to operate the switch device regardless of the rotational orientation of the steering wheel.

It is to be understood that the term "switch device" includes any suitable device that is arranged to open and/or close an electrical circuit and/or cause a change in the output characteristics of a device that can be measured so that it is possible to determine that the driver has performed a switching operation. For example, the switch device may include at least one set of electrical contacts that can be selectively opened and closed by the driver and /or at least one device for detecting a change in the load applied to the steering wheel by the driver and/or the orientation of the switch element, such as a strain gauge or other sensor. The change in output of the strain gauge or other sensor can be detected and used to control an electrical or electromechanical system.

Preferably the switch element is flexible and is arranged for rotation about a curved axis.

According to another aspect of the invention there is provided a steering wheel including a substantially annular steering member and a switch device provided on the substantially annular steering member, wherein the switch device is operable by actuating at least one switch element comprising at least a portion of the substantially annular steering member, wherein the switch element is flexible and is arranged for rotation about a curved axis. Thus the invention does not require a rectilinear axis in order for the switch device to operate. This enables the steering wheel

to retain a more circular shape, which is preferred by drivers, and enables embodiments wherein he switch element can extend around a substantial part of the steering wheel.

Advantageously the curved axis is concentric with the annular steering member.

Advantageously the switch element is arranged to be actuated by twisting. Preferably the switch device is arranged such that twisting the switch element in a first direction produces a first control signal for controlling operation of a first operable device and twisting the switch element in a second direction produces a second control signal for controlling operation of a second operable device. In preferred embodiments the switch element is arranged to be twisted towards the driver in order to initiate an upshift in a transmission system.

The switch device may comprise either a single switch element or a plurality of switch elements distributed around the circumference of the steering wheel to achieve the effect of being actuateable around substantially the entire annular steering member.

For example, the switch device may one of the following arrangements: one switch element that extends around between 270 and 360 degrees of the steering member; at least one arcuate switch element that extends through approximately 180 degrees of the steering member, and preferably two switch elements; the switch device includes at least one arcuate switch element that extends through approximately 120 degrees of the steering member, and preferably three switch elements; the switch device includes at least one arcuate switch element that extends through approximately 90 degrees of the steering member, and preferably four switch elements; the switch device includes at least one arcuate switch element that extends through approximately 72 degrees of the steering member, and preferably five switch elements; the switch device includes at least one arcuate switch element that extends through approximately 60 degrees of the steering member, and preferably six switch elements. Advantageously the portions may be spaced apart, for example a steering wheel can include five switch devices each having arcuate switch elements that extend through approximately 60 degrees with non-switchable portions of the steering member located between. In other arrangements, dissimilar switch element sizes can be used, for example two switch elements that extend through an angle of 90 degrees with one

switch element that extends through an angle of around 180 degrees. Any practicable number of switch elements can be used. Each contact can be different.

Preferably the steering member includes a substantially rigid structural element and a flexible outer member. Preferably the structural element is electrically conductive and the outer member is electrically insulating.

Preferably the switch device has first and second electrical contacts, wherein the first electrical contact extends around one side of the steering member. For example, the first electrical contact may be substantially annular. Alternatively, the first and second electrical contacts may extend around an arc of the steering member. Advantageously the first electrical contact is supported by at least one resiliently deformable support member. Preferably the or each resiliency deformable support member is arranged to hold the first electrical contact in a first position where it is not connected to the second electrical contact and is deformable to allow movement of the first electrical contact to a second position where it is electrically connected with the second electrical contact when the switch element is twisted by the driver. Preferably the resiliently deformable support member is annular. Advantageously the second electrical contact may comprise a structural element of the steering member. The second electrical contact may be substantially annular.

Preferably the switch device includes a third electrical contact mounted on the opposite side of the steering member to the first electrical contact to enable bi-directioήal switching. The third electrical contact may be mounted in a second resiliently deformable support member, the arrangement being such that, in use _/ , twisting the switch element in a first direction moves the first electrical contact into engagement with the second electrical contact and twisting the switch element in a second direction moves the third electrical contact into engagement with the second electrical contact.

Preferably the switch device is arranged for limited rotation in each direction, for example within ±5 to 90 degrees, and preferably around ±45 degrees.

Advantageously the switch device may include a plurality of electrical contacts on one side of the steering member each extending across a segment of the steering member wherein the switch

device is operable by twisting the switch element. Preferably the switch device includes a plurality of electrical contacts on the opposite side of the steering member to enable bidirectional switching. Preferably at least one of the electrical contacts is arcuate. At least one of the contacts can be mounted in a resiliently deformable support member.

Preferably at least one of the electrical contacts mentioned above is resilient.

Preferably the switch device includes a plurality of strain gauges or sensors distributed around the steering member arranged to detect a switching action substantially anywhere around the steering member. This can be in addition to or as an alternative to the electrical contacts. The switch device may also include means for detecting a change in output of the strain gauge or sensor, though this may be incorporated into a separate circuit.

Advantageously the switch device may include resilient means for biasing the or each switch element into a predetermined operational condition, for example into the open (neutral) position. More preferably, the resilient means is strong enough that operation must be deliberate.

The switch device may include means for providing tactile feedback to the user to indicate the operational condition of the switch device, for example the device may include a detent and depression arrangement, or ridge and groove arrangement, to provide tactile feedback when the switch is moved to / from the open position.

Advantageously the switch device may include means for providing an audible sound to indicate the operational condition of the switch device. For example, the friction between components can be arranged to provide an audible click as the switch device is operated. Alternatively, an audio output device can be included in the electrical circuit to provide different audio output for different operational states of the switch device.

Preferably the switch device includes visual means for indicating the operational condition of the switch device, for example at least one LED that is arranged to be illuminated when the switch device is closed.

Preferably the steering wheel includes an outer covering or skin. For example, the steering member may be covered by leather.

Since the switch device is located on the steering member it can be operated by a user of the steering wheel without having to remove his / her hands from the steering member. Advantageously the switch device is connected to an electrical circuit or at least one electromechanical device. The switch device can be arranged to control any electrical and / or electromechanical device in a vehicle or games console, for example a gear selection system, entertainment system, climate control system, lighting system, throttle control system, brake system, cruise control system, navigation system, telecommunications system or onboard computer.

Advantageously the electrical circuit includes an electronic control unit for determining the device or system to be controlled by the switch device. Preferably the electrical circuit includes mode selection means and the electronic control unit is arranged to receive inputs from the mode selection means to determine the electrical circuit(s) or electromechanical device(s) / systems controlled by the switch device. Preferably the mode selection means includes at least one manually operable input device, such as a switch mounted on the hub of the steering wheel. The user of the steering wheel may operate the or each manually operable switch to determine the device, system or circuit to be controlled by the switch device located on the steering member. For example, in a first mode the switch device is arranged to control a gear selection mechanism to enable a user to select between gear ratios without moving his or her hands from the steering wheel. In this instance the switch device can be arranged to select higher or lower gears by initiating sequential or non-sequential gear selections. In a second mode the switch device is arranged to control the throttle. Advantageously some embodiments include a plurality of switch devices located on the substantially annular steering member. In those embodiments a first switch device can be arranged to control a first device, system or circuit and a second switch device can be arranged to control a second device, system or circuit. In some operational modes, the first and second switch devices can be used to control different operations of the same device, system or circuit.

Advantageously the electronic control unit can be arranged to determine the length of time that the switch device is closed and thereby determine the appropriate switching action, for example how many gear ratios to shift up or down, or how far to increase or decrease audio volume. If the

switch device is held closed for a predetermined period of time in a particular mode of operation this may indicate that the user is performing a rapid deceleration and the electronic control unit can send a signal to a gear selection mechanism to select a gear appropriate to the road speed. For example, when driving in third to sixth gears (or higher) the switch device can be operated to select first gear to help arrest movement of the vehicle more quickly.

Additionally, or alternatively, the electronic control unit can be arranged to detect the speed of operation of switching in order to determine the switching operation to be performed.

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which like references indicate equivalent features, wherein:

Figure 1 is a front view of a steering wheel according to a first embodiment of the invention;

Figure 2 is a sectional view of the steering wheel of Figure 1 along A-A;

Figure 3 is a schematic electrical circuit for the steering wheel of Figure 1;

Figure 4 is a front view of a steering wheel according to a second embodiment of the invention;

Figure 5 is a front view of a steering wheel according to a third embodiment of the invention; and

Figure 6 is a front view of a steering wheel according to a fourth embodiment of the invention.

A first embodiment of the steering wheel 1 is shown in Figures 1 to 3 that is arranged to enable the driver to perform a switching operation anywhere around the circumference of the steering wheel 1.

The steering wheel 1 includes a substantially annular member 3, a switch device 5, a hub 7 for attaching the steering wheel to a steering column and two spokes 8 for connecting the annular

member 3 to the hub 7. The steering wheel 1 is arranged in the conventional fashion similar to that described above.

As can be seen in Figures 1 and 2, the annular member 3 comprises an inner core 9, an outer core 11 and an outer skin 13. The inner core 9 is substantially annular and has a cross-section that includes a substantially circular part 10 and a rectangular part 12 that define a hoop-like structure with a flange extending radially outwards therefrom. The inner core 9 also includes a ridge member 14. The inner core 9 is metallic and is preferably made from aluminium.

The outer core 11 has a circular cross-section and is located about the inner core 9. The outer core 11 includes a cavity arranged to accommodate the inner core 9 and components of the switch device 5. Preferably the outer core 11 is made from foam.

The switch device 5 is part of an electric circuit that can be used to control electrical and electromechanical systems in a vehicle. Preferably the circuit includes an electronic control unit 28 and at least one manually operable input device, such as a switch, to enable the driver to select different switching modes. For example, the electronic control unit 28 can be electrically connected to an actuator device in a transmission system (not shown), for example the electromagnetic actuator device described in WO 2005/026570, the contents of which are hereby incorporated by reference, to control the selection of gear ratios. Thus the switch device 5 is fully integrated with the steering wheel 1 and the driver is able to change gear whilst driving a vehicle without removing his or her hands from the steering wheel 1.

The switch device 5 includes first and second contact supports 16,18, first and second electrical contacts 23,25 and a third electrical contact, which comprises the inner core 9. The first and second contact supports 16,18 are annular and have a generally E-shaped cross-section and include first and second rims 20,22 and a central annular member 24. Each contact support 16,18 has an outer surface 26 that is generally rounded, for example may comprise straight and curved portions to provide a convex outer surface 26. Each contact support 16,18 is mounted on the flange of the inner core 9. The contact supports 16,18 are flexible and are preferably made from a plastics material such as nylon. At least a part of each contact support 16,18 is arranged for resilient deformation in response to a torque applied to the steering wheel by the driver of the

vehicle. The torque is transmitted to the contact support 16,18 via ridges 34,36 formed in the outer core 11.

Each electrical contact 23,25 is annular and has a corrugated form that allows the contacts to deform resiliently 23,25. Each contact 23,25 is mounted in slots formed in the first and second rims 20,22 of the contact supports such that the contacts 23,25 are normally held out of engagement with the inner core 9. When one of the contact supports 16,18 is resiliently deformed by the twisting action of the driver on the outer core 11, the central annular member 24 causes one of the electrical contacts 23,25 to resiliently deform so that it makes contact with the inner core 9. The actual contact deformed will depend upon the direction of torque. When one of the electrical contacts 23,25 engages the inner core 9 the switch device 5 is closed and an electrical signal is sent to the electronic control unit 28. Depending on which mode has been selected (see below), the electronic control unit 28 determines which device, system or circuit to operate and the control signal to be sent. For example, if a gear selection system is being controlled, the electronic control unit 28 determines whether an up-shift or a down-shift has been selected based upon the switching connection made and operates gear selection actuators accordingly.

The ridge member 14 provides tactile feedback to the driver to indicate when the switch device 5 is closed and open. When the switch device 5 is in the open (neutral) position the ridge member 14 is located in a groove 32 formed in the outer core 11. When the driver operates the switch device 5 the outer core 11 resiliently deforms or moves relative to the ridge member 14 and thus the ridge member 14 is at least partially moved out of the groove 32. The driver is able to detect the movement via tactile feedback. Similarly, when the outer core 11 returns to the neutral position and the ridge member 14 enters the groove 32 there is tactile feedback to the driver.

Preferably the switch device 5 is arranged such that rotating the switch in a first direction selects a higher gear and rotating in the opposite direction selects a lower gear. Alternatively, the switches can be arranged such that the left hand selects a higher gear and the right hand a lower gear. It will be apparent to the skilled person that many switching arrangements are possible, that are within the scope of the invention.

The electronic control unit 28 can include means for monitoring how long the switch is held in a closed position. This can have significance for determining which gear is to be selected. For example, if both switches are operated simultaneously and held for a predetermined period the electronic control unit 28 may move from the engaged gear, say fifth gear, to first gear since this may signify that the driver wants to perform an emergency stop. Another combination of switching operations may indicate to the electronic control system that the next gear should not be selected until a certain threshold has been reached, for example a certain engine speed, to obtain high accelerations. Another switching combination may be used to make a "short-shift" gear change, that is, when a lower gear is selected very briefly before selecting the next lower gear, or conversely selecting a higher gear very briefly before selecting the next higher gear. This technique is often used in motor sports for example when negotiating a bend. This is particularly useful for those types of transmission systems that cannot skip gear ratios.

Additionally, or alternatively, the switch device 5 can be arranged to control any other electrical system in the vehicle, for example a lighting system, climatic control system, entertainment system, a lock system, any digital device such as an onboard computer, navigation system or telecommunications device. The switches can also be used to control any electro-mechanical system, for example a system that includes electrically controlled actuators to control mechanical devices to perform a function such as accelerating or braking the vehicle.

The switch device 5 can be connected to a circuit that enables different switching modes to be selected, for example the modes shown in Table 1.

Table 1

Preferably the circuit includes an electronic control unit and at least one manually operable input device to, enable the driver to select between switching modes. This enables the switch device 5 to control several different functions by selecting between operational modes. The computer may control any of the vehicle systems. Thus the driver can set functional parameters of onboard electrical and electro-mechanical systems without moving his/her hands from the steering wheel. Preferably the system is arranged such that the driver can select different modes when driving the vehicle, for example by operating one or more switches. The switches may also be mounted on the steering wheel, for example on the hub 7.

The circuit may include visual indicators to indicate when the switch device 5 is closed, for example to indicate which electrical • contact 23,25 is engaging the inner core 9. The visual indicator may take the form of different coloured LEDs 30.

Several switch devices can be included around the circumference of the steering wheel so that gear changes can be made regardless of the orientation of the steering wheel. This allows the driver to change gear even when negotiating very tight bends should that be necessary. Figures 4 to 6 show three alternative steering wheels 101,201,301 each including a plurality of switch devices similar to that described above. Figure 4 shows a steering wheel 101 having two spokes 108 and two switch devices 105 that each extend through approximately 180 degrees, Figure 5 shows a steering wheel 201 having three spokes 208 and three switch devices 205 that each extend through approximately 120 degrees, and Figure 6 shows a steering wheel 301 having four spokes 308 and four switch devices 308 that each extend through approximately 90 degrees. The switch devices can be arranged to have very short lengths so that many switches can be included around the circumference of the steering wheel. Any practicable number of switches can be included. This enables the switch devices to be operated regardless of the orientation of the steering wheel. This allows the driver to change gear even when negotiating very tight bends should that be necessary.

It will be apparent to the skilled person that the switch devices used in the second, third and fourth embodiments can extend over a smaller arc than indicated above and can be separated by gaps to account, for example for steering wheel spokes.

The contacts may be spaced apart around the circumference of the steering wheel, for example to avoid steering wheel spokes or if switching is not required at certain parts of the steering wheel. The arcuate length of each contact can be determined accordingly, for example if two contacts are required to extend around substantially the whole of one side of the steering wheel each contact will extend through approximately 180 degrees. The contacts may be slightly shorter if it is necessary to avoid parts of the steering wheel where the spokes connect with the inner core. The contacts can extend through any angle, for example any angle between 20 to 360 degrees. The contact supports may be annular or may be sized in accordance with the arc of the contacts.

When more than one switch device is included, each switch device can be arranged to have a different control function in a particular mode. Table 2 below shows the additional functionality that can be achieved for example when having left and right hand parts to the switch device:

Table 2

The steering wheels described above may be used for motor cars, games consoles, arcade machines, simulator / trainer systems, go-karts, racing cars, other road vehicles, lorries, military vehicles, construction vehicles, boats and hovercraft, or any other application requiring a steering wheel and at least one switch.

The inner core does not necessarily have to form part of the electrical circuit, other electrical contacts could be mounted on the inner core as an alternative and the inner core could be purely for structural purposes.

A strain gauge or other similar sensor can be used to detect the switching action performed by the user in order to produce an electrical signal that can be used to control an electrical or an electromechanical system in or on the vehicle, for example the electrical and electromechanical systems mentioned above. In each case, one or more strain gauges or sensors are arranged to detect switching actions substantially anywhere around the circumference of the steering member. This can be achieved by using a single strain gauge or sensor or a plurality of strain gauges or sensors distributed around the circumference of the steering wheel. For example, the strain gauge can be arranged to detect a twisting load applied to the steering wheel by the driver, which will change the output of the strain gauge. This can be detected and used as a control signal for another electrical system.

It will be apparent to the skilled person that it is possible to use multiple switch elements of very short length that are distributed around the steering wheel in order to provide the effect of the switch device being operable around its entire circumference.