Patent Description:
A transmission-reception system has been known that includes a receiver and a transmitter configured to be attached to a tire valve. Such a transmission-reception system is disclosed, for example, in Patent Document <NUM>. The transmitter includes a sensor, a data generating unit configured to generate transmission data, and a transmitting unit configured to transmit the transmission data. The transmitter is integrally provided, for example, in a tire valve attached to a wheel. The receiver receives the transmission data transmitted by the transmitter. Patent Document <NUM> relates to a wheel unit for a system for transmitting data from the wheel unit to a receiver of a vehicle, wherein the wheel unit is designed to be mounted to a wheel of the vehicle, and wherein the wheel unit comprises a storage for storing wheel type data related to the type of the wheel at which the wheel unit is mounted; a processor for processing the wheel type data stored in the storage and a transmitter for RF-transmitting data telegrams to a vehicle-mounted receiver. Patent Document <NUM> relates to a system for theft protection for vehicle wheels of a vehicle, having a database server for managing vehicle wheel identification data identifying vehicle wheels and a controller, wherein the controller has a communication connection to the database server via a communication network, wherein the vehicle wheels of the vehicle are each equipped with an electronic wheel unit for transmitting vehicle wheel identification data, respectively identifying the vehicle wheel in question, to the controller, and wherein the controller is designed to transmit the vehicle wheel identification data, transmitted by the electronic wheel units of the vehicle wheels, to the database server via the communication network. Patent Document <NUM> discloses a device for detecting and signaling a physical value when connected to a rim in a position below a pneumatic tire mounted on the rim, and further comprising a device to discover a detachment of the device from the rim.

There has been a demand to properly control a vehicle by using a transmission-reception system.

It is an objective of the present disclosure to provide a transmitter, a receiver, and a transmission-reception system that are capable of properly controlling a vehicle. Means for Solving the Problems.

In accordance with a first aspect of the present invention, a transmitter configured to be integrated with a tire valve attached to a wheel is provided. The transmitter includes a data generating unit, a transmitting unit, and a controlling unit. The data generating unit is configured to generate transmission data. The transmitting unit is configured to transmit the transmission data to a receiver. The receiver includes a setting unit that sets a threshold related to control of a vehicle in accordance with a type of the wheel. The controlling unit is configured to cause the transmitting unit to transmit the transmission data. The transmission data includes wheel identification information. The wheel identification information is required by the setting unit when setting the threshold and allows the setting unit to recognize the type of the wheel to which the tire valve is attached. The transmitter further comprises a metal member that is configured such that an inductance changes in accordance with the type of the wheel to which the transmitter is attached; an inductance measuring unit configured to measure the inductance of the metal member; and a determining unit configured to determine a type of the wheel to which the transmitter is attached based on the inductance of the metal member measured by the inductance measuring unit.

With this configuration, the transmitter transmits the transmission data including the wheel identification information. The wheel identification information is configured to allow the setting unit of the receiver to recognize the type of the wheel. This allows the receiver to recognize the type of the wheel to which the transmitter is attached from the wheel identification information. Since the setting unit sets the threshold used in the control of the vehicle in accordance with the type of the wheel, the vehicle can be controlled properly in accordance with the type of the wheel.

The wheel may be selected as one of an aluminum wheel and a steel wheel.

Steel has a higher magnetic permeability than aluminum. The inductance of the metal member changes depending on whether the wheel is made of steel or aluminum. It is thus possible to determine the type of the wheel by measuring the inductance of the metal member.

The metal member may have a shape of a loop.

The transmitter may be arranged in the wheel such that a loop plane, which is an imaginary plane surrounded by the metal member, is orthogonal to a centrifugal direction of the wheel.

In accordance with a second aspect of the present invention, a transmitter configured to be integrated with a tire valve attached to a wheel is provided. The transmitter includes an acceleration sensor, a data generating unit, a transmitting unit, a determining unit, a warning transmission controlling unit, and a warning threshold setting unit. The acceleration sensor is configured to detect a centrifugal acceleration that acts on the transmitter as the wheel rotates. The data generating unit is configured to generate transmission data. The transmitting unit is configured to transmit the transmission data to a receiver. The determining unit is configured to determine a type of the wheel to which the transmitter is attached. The warning transmission controlling unit is configured to cause the transmitting unit to perform warning transmission for causing the receiver to issue a warning when a detection value of the acceleration sensor exceeds a threshold. The warning threshold setting unit is configured to set the threshold in accordance with the type of the wheel determined by the determining unit.

With this configuration, the warning threshold setting unit is capable of setting a threshold corresponding to the type of the wheel. When the detection value of the acceleration sensor exceeds the threshold, the warning transmission controlling unit causes the transmitting unit to perform the warning transmission. This allows the receiver to issue a warning. The receiver is allowed to issue a warning, which is one mode of the vehicle control, in accordance with the type of the wheel. The vehicle can thus be controlled properly in accordance with the type of the wheel.

In accordance with a third aspect of the present invention, a receiver is provided that is configured to receive transmission data transmitted from a transmitter integrated with a tire valve attached to a wheel. The receiver includes a receiving unit, a receiver memory unit, an obtaining unit, and a setting unit. The receiving unit is configured to receive the transmission data. The receiver memory unit is configured to store a correspondence relationship between a type of the wheel and a threshold related to control of a vehicle. The obtaining unit is configured to obtain wheel identification information from the transmission data received by the receiving unit. The setting unit is configured to recognize, from the wheel identification information, the type of the wheel to which the tire valve is attached, and to set, from the correspondence relationship, the threshold in accordance with the recognized type of the wheel.

With this configuration, since the setting unit of the receiver sets the threshold related to the control of the vehicle from the wheel identification information obtained from the transmission data, the vehicle can be controlled properly in accordance with the type of the wheel.

The threshold may include an upper limit of a vehicle speed of the vehicle.

The vehicle speed that can be handled can vary depending on the type of the wheel. Since the upper limit of the vehicle speed is set in accordance with the type of the wheel, control corresponding to the type of the wheel can be performed.

In accordance with a fourth aspect of the present invention, a transmission-reception system is provided that includes a transmitter configured to be integrated with a tire valve attached to a wheel, and a receiver configured to receive transmission data transmitted from the transmitter. The transmitter includes a data generating unit configured to generate the transmission data, a transmitting unit configured to transmit the transmission data, and a controlling unit configured to cause the transmitting unit to transmit the transmission data. The transmission data includes wheel identification information that indicates a type of the wheel to which the tire valve is attached. The receiver includes a receiving unit, a receiver memory unit, an obtaining unit, and a setting unit. The receiving unit is configured to receive the transmission data. The receiver memory unit is configured to store a correspondence relationship between the type of the wheel and a threshold related to control of a vehicle. The obtaining unit is configured to obtain the wheel identification information from the transmission data received by the receiving unit. The setting unit is configured to recognize, from the wheel identification information, the type of the wheel to which the tire valve is attached, and to set, from the correspondence relationship, the threshold in accordance with the recognized type of the wheel.

With this configuration, since the setting unit of the receiver sets the threshold related to the control of the vehicle based on the wheel identification information obtained from the transmission data, the vehicle can be controlled properly in accordance with the type of the wheel.

The present disclosure is capable of allowing control of a vehicle to be properly performed.

A transmitter, a receiver, and a transmission-reception system according to a first embodiment will now be described.

As shown in <FIG>, a vehicle <NUM> includes four wheel assemblies <NUM> and an ECU <NUM>. The ECU <NUM> is an electronic control unit that includes a CPU <NUM> and a memory unit <NUM>, which are hardware. The ECU <NUM> performs control such as control of traveling of the vehicle <NUM>. The memory unit <NUM> stores various programs for controlling the vehicle <NUM>. The CPU <NUM> executes various processes by referring to the memory unit <NUM>. The CPU <NUM>, which is processing circuity, may include one or more processors that operate according to a computer program, one or more dedicated hardware circuits such as an ASIC, or a combination thereof. The memory unit <NUM> includes memory such as a RAM and a ROM. The memory stores program code or instructions configured to cause the CPU to execute processes. The memory, or computer readable medium, includes any type of medium that is accessible by general-purpose computers and dedicated computers.

The vehicle <NUM> has a transmission-reception system <NUM>. The transmission-reception system <NUM> includes transmitters <NUM> and a receiver <NUM>. Each transmitter <NUM> is configured to be installed in one of the four wheel assemblies <NUM> of the vehicle <NUM>. The receiver <NUM> is configured to be installed in the vehicle <NUM>.

As shown in <FIG>, the wheel assembly <NUM> includes a wheel <NUM> and a tire <NUM> mounted on the wheel <NUM>. The wheel <NUM> includes a rim <NUM>. The rim <NUM> has a mounting hole <NUM> extending through the rim <NUM>. The inner circumferential surface of the mounting hole <NUM> is a mounting hole forming surface <NUM>. The transmitter <NUM> is configured to be attached to the tire valve installed in the rim <NUM> of the wheel <NUM> to be integrated with the tire valve. The transmitter <NUM> is thus installed in the wheel assembly <NUM>. The transmitter <NUM> is attached to the wheel <NUM>, on which the tire <NUM> is mounted, such that the transmitter <NUM> is arranged inside the tire <NUM>. The transmitter <NUM> detects the condition of the corresponding tire <NUM>, for example, the air pressure and internal temperature of the tire <NUM>, and wirelessly transmits a data signal including the detection results to the receiver <NUM>. The transmission-reception system <NUM> is configured to monitor the condition of the tire <NUM> by receiving the data signal transmitted from the transmitter <NUM> at the receiver <NUM>.

The transmitter <NUM> is configured to be attachable to multiple types of tire valves. In the present embodiment, the transmitter <NUM> is attachable to selected one of two types of valves: a clamp-in valve <NUM> and a snap-in valve <NUM>.

The transmitter <NUM> includes a case <NUM>. The case <NUM> includes a case body <NUM>, which accommodates components of the transmitter <NUM>, and an attachment wall <NUM>, to which a tire valve is attached. The attachment wall <NUM> includes an insertion portion <NUM>, into which a tire valve is inserted, and an insertion hole <NUM>, into which a screw <NUM> for attaching the tire valve to the case <NUM> is inserted. The insertion portion <NUM> is a part of the attachment wall <NUM> that is recessed in the thickness direction of the attachment wall <NUM>. The insertion hole <NUM> extends through the attachment wall <NUM> in the thickness direction of the attachment wall <NUM>. The insertion hole <NUM> opens to the insertion portion <NUM>.

The clamp-in valve <NUM> includes a tubular valve stem <NUM>. The valve stem <NUM> is made of metal. The valve stem <NUM> includes a flange <NUM> and a fastening portion <NUM>. The flange <NUM> and the fastening portion <NUM> are spaced apart from each other in the axial direction of the valve stem <NUM>. The flange <NUM> is a part of the valve stem <NUM> that is locally enlarged in the radial direction. The fastening portion <NUM> is a part of the valve stem <NUM> that has a threaded outer circumferential surface. That is, the fastening portion <NUM> is an external thread. When the clamp-in valve <NUM> is installed in the wheel <NUM>, the flange <NUM> is located inside the tire <NUM>, and the fastening portion <NUM> is located outside the tire <NUM>. The clamp-in valve <NUM> is installed in the wheel <NUM> with a grommet <NUM> disposed between the wheel <NUM> and the flange <NUM>. A nut <NUM> is mounted on the fastening portion <NUM>. The nut <NUM> and the flange <NUM> hold the wheel <NUM> and the grommet <NUM> in between to ensure the sealing property of the mounting hole <NUM>. When the clamp-in valve <NUM> is used as the tire valve, the valve stem <NUM> faces a mounting hole forming surface <NUM>. When the transmitter <NUM> is attached to the clamp-in valve <NUM>, a part of the valve stem <NUM> is inserted into the insertion portion <NUM>. Then, the screw <NUM>, which is inserted into the insertion hole <NUM>, is fastened to the valve stem <NUM>, so that the transmitter <NUM> is attached to the clamp-in valve <NUM>.

As shown in <FIG>, the snap-in valve <NUM> includes a tubular valve stem <NUM> and a cylindrical body <NUM>, which is disposed on the outer circumference of the valve stem <NUM>. The valve stem <NUM> is made of metal, and the body <NUM> is made of rubber. The opposite ends of the valve stem <NUM> protrudes from the body <NUM>. The body <NUM> includes a mount portion <NUM>. The body <NUM> also includes a first holding portion <NUM> and a second holding portion <NUM>, which are provided on opposite sides of the mount portion <NUM>. The mount portion <NUM> is a part of the body <NUM> that is recessed in the radial direction and disposed over the entire circumference of the body <NUM>. The diameter of the first holding portion <NUM> and the diameter of the second holding portion <NUM> are greater than the diameter of the mount portion <NUM>. The snap-in valve <NUM> is installed in the wheel <NUM> by press-fitting the body <NUM> into the mounting hole <NUM>. The first holding portion <NUM> and the second holding portion <NUM> hold the wheel <NUM> in between, and the mount portion <NUM> closely contacts the mounting hole forming surface <NUM>. The body <NUM> of the snap-in valve <NUM> ensures the sealing property of the mounting hole <NUM>. When the transmitter <NUM> is attached to the snap-in valve <NUM>, a part of the valve stem <NUM> is inserted into the insertion portion <NUM>. Then, the screw <NUM>, which is inserted into the insertion hole <NUM>, is fastened to the valve stem <NUM>, so that the transmitter <NUM> is attached to the snap-in valve <NUM>.

As shown in <FIG>, the transmitter <NUM> includes a pressure sensor <NUM>, a temperature sensor <NUM>, an acceleration sensor <NUM>, a transmitter controlling unit <NUM>, a transmission circuit <NUM>, a transmission antenna <NUM>, a battery <NUM>, an inductance measuring unit <NUM>, and a pattern member <NUM>. These components are accommodated in the case body <NUM>. The interior of the case body <NUM> may be filled with plastic without gaps. That is, the case <NUM> may be molded so that the components of the transmitter <NUM> are embedded in the case body <NUM>.

The pressure sensor <NUM> is configured to detect the pressure of the corresponding tire <NUM>. The pressure sensor <NUM> outputs the detection result to the transmitter controlling unit <NUM>. The temperature sensor <NUM> is configured to detect the temperature of the corresponding tire <NUM>. The temperature sensor <NUM> outputs the detection result to the transmitter controlling unit <NUM>.

The acceleration sensor <NUM> is configured to rotate integrally with the wheel <NUM> to detect the centrifugal acceleration acting on the transmitter <NUM>. Specifically, the acceleration sensor <NUM> has a detection axis and detects acceleration that acts in the direction along the detection axis. The acceleration sensor <NUM> is disposed such that a force directed in the radial direction of the wheel <NUM> acts on the detection axis, so as to detect the centrifugal acceleration acting on the transmitter <NUM>. The centrifugal acceleration acting on the transmitter <NUM> can be regarded as the centrifugal acceleration acting on the wheel <NUM>. The acceleration sensor <NUM> outputs the detection result to the transmitter controlling unit <NUM>.

The transmitter controlling unit <NUM> is composed of circuitry such as a microcomputer including a CPU 25a and a memory unit 25b such as a RAM and a ROM. An ID code, which is identification information unique to each transmitter <NUM>, is registered in the memory unit 25b. The memory unit 25b stores various programs for controlling the transmitter <NUM>. The transmitter controlling unit <NUM> may include dedicated hardware that executes at least part of various processes, that is, an application specific integrated circuit (ASIC). The transmitter controlling unit <NUM>, which is processing circuity, may include one or more processors that operate according to a computer program, one or more dedicated hardware circuits such as an ASIC, or a combination thereof. The processor includes a CPU and memory such as a RAM, a ROM, and the like. The memory stores program code or instructions configured to cause the CPU to execute processes. The memory, or computer readable medium, includes any type of media that are accessible by general-purpose computers and dedicated computers.

The transmitter controlling unit <NUM> generates transmission data and outputs it to the transmission circuit <NUM>. The transmission data includes, for example, pressure data and transmission data. The pressure data indicates the detection value of the pressure sensor <NUM>. The temperature data indicates the detection value of the temperature sensor <NUM>. The transmission circuit <NUM> modulates the transmission data from the transmitter controlling unit <NUM> to generate a data signal, and transmits the data signal through the transmission antenna <NUM>. Accordingly, the transmission data is transmitted as the data signal. Any suitable modulation technique can be performed by the transmission circuit <NUM>. The transmitter controlling unit <NUM> is a data generating unit configured to generate the transmission data. The transmission circuit <NUM> is a transmitting unit that is configured to transmit the transmission data as the data signal. The data signal is transmitted at a predetermined interval. For example, a signal of a frequency in a radiofrequency band is used as the data signal.

The inductance measuring unit <NUM> measures the inductance of the pattern member <NUM>. The inductance measuring unit <NUM> outputs the detection result to the transmitter controlling unit <NUM>.

As shown in <FIG>, the pattern member <NUM> is provided in a substrate <NUM>. Although not illustrated, the above-described components such as the transmitter controlling unit <NUM> and the pressure sensor <NUM> are mounted on the substrate <NUM>. For purposes of illustration, the pattern member <NUM> is illustrated in an exaggerated manner.

The pattern member <NUM> is a loop-shaped metal member. The pattern member <NUM> is made of, for example, copper or aluminum. The pattern member <NUM> is connected to the inductance measuring unit <NUM>. The pattern member <NUM> of the present embodiment is an inductance measuring pattern member that is provided to measure inductance. The pattern member <NUM> is also used as a connecting member that connects components of the transmitter <NUM> to one another.

As shown in <FIG> and <FIG>, the pattern member <NUM> is provided on one of opposite surfaces of the substrate <NUM>, and the transmitter <NUM> is arranged such that the surface of the substrate <NUM> on which the pattern member <NUM> is provided faces the rim <NUM> of the wheel <NUM>. The transmitter <NUM> is arranged such that a loop plane S, which is an imaginary plane surrounded by the pattern member <NUM>, is orthogonal to the centrifugal direction of the wheel <NUM>. In other words, the transmitter <NUM> is arranged such that the central axis of the pattern member <NUM> extends in a centrifugal direction of the wheel <NUM>. In this description, the term "orthogonal" includes slight displacements due to the mounting accuracy of the transmitter <NUM> and tolerances of the components.

As shown in <FIG>, the receiver <NUM> includes a receiver controlling unit <NUM>, a reception circuit <NUM>, and a reception antenna <NUM>. The reception circuit <NUM> demodulates the data signal that has been transmitted from each transmitter <NUM> and received via the reception antenna <NUM>, and delivers the demodulated signal to the receiver controlling unit <NUM>. The reception circuit <NUM> is a receiving unit that receives the transmission data. The receiver controlling unit <NUM> is connected to a warning device <NUM>.

The receiver controlling unit <NUM> is composed of a microcomputer including a receiver CPU 41a and a receiver memory unit 41b such as a ROM and a RAM. The receiver controlling unit <NUM> may include dedicated hardware that executes at least part of various processes, that is, an application specific integrated circuit (ASIC). The receiver controlling unit <NUM>, which is processing circuity, may include one or more processors that operate according to a computer program, one or more dedicated hardware circuits such as an ASIC, or a combination thereof. The processor includes a CPU and memory such as a RAM, a ROM, and the like. The memory stores program code or instructions configured to cause the CPU to execute processes. The memory, or computer readable medium, includes any type of media that are accessible by general-purpose computers and dedicated computers.

The receiver memory unit 41b stores the ID codes of the respective transmitters <NUM>. The receiver controlling unit <NUM> verifies whether the ID code included in the transmission data matches the ID code stored in the receiver memory unit 41b. If the ID code included in the transmission data matches the ID code stored in the receiver memory unit 41b, the receiver controlling unit <NUM> uses the pressure data and the temperature data included in the transmission data as data representing the condition of the tire <NUM>.

The receiver controlling unit <NUM> acquires the condition of the tire <NUM> from the received transmission data. When there is an anomaly in the tire <NUM>, the receiver controlling unit <NUM> performs notification by using the warning device <NUM>. The warning device <NUM> may be, for example, a device that notifies the user of an anomaly by sound, or illumination or blinking of light. Also, the receiver controlling unit <NUM> may display the condition of the tire <NUM> on the display device, which can be visually recognized by the occupants of the vehicle <NUM>.

The transmission-reception system <NUM> of the present embodiment is configured to control the vehicle <NUM> in accordance with the type of the wheel <NUM>. The process executed by the transmitter <NUM> and the receiver <NUM> will now be described. The process allows the vehicle <NUM> to be controlled in accordance with the type of the wheel <NUM>.

As shown in <FIG>, the transmitter controlling unit <NUM> determines the type of the wheel <NUM> to which the tire valve is attached in step S1. The types of the wheel <NUM> include an aluminum wheel and a steel wheel. An aluminum wheel is a wheel <NUM> made of aluminum. Aluminum incudes aluminum alloys. A steel wheel is a wheel <NUM> made of steel. The transmitter controlling unit <NUM> determines whether the wheel <NUM> is an aluminum wheel or a steel wheel.

The transmitter controlling unit <NUM> determines the type of the wheel <NUM> by using the measured value of the inductance measuring unit <NUM>. When the inductance measuring unit <NUM> measures the inductance of the pattern member <NUM>, an electric current is passed through the pattern member <NUM>. The transmitter <NUM> may include a switch (not shown) so as to pass an electric current through the pattern member <NUM> only when measuring the inductance of the pattern member <NUM>.

When an electric current is passed through the pattern member <NUM>, magnetic flux B is generated as shown in <FIG>. The magnetic flux B is generated in a manner penetrating the loop plane S. Since the magnetic flux B penetrates the wheel <NUM>, an inductor is formed in which the pattern member <NUM> serves as wiring and the wheel <NUM> serves as a core. The inductance of the pattern member <NUM> increases as the magnetic permeability of the wheel <NUM>, which serves as a core, increases. Steel is an alloy that has iron, which is a magnetic material, as a main component, and thus has a higher magnetic permeability than aluminum. Therefore, the inductance measured by the inductance measuring unit <NUM> varies between a case in which the wheel <NUM> is an aluminum wheel and a case in which the wheel <NUM> is a steel wheel. The transmitter controlling unit <NUM> determines that the wheel <NUM> is a steel wheel when the inductance measured by the inductance measuring unit <NUM> is greater than or equal to a predetermined determination threshold. On the other hand, the transmitter controlling unit <NUM> determines that the wheel <NUM> is an aluminum wheel when the inductance measured by the inductance measuring unit <NUM> is less than the predetermined determination threshold. The determination value is set to distinguish an aluminum wheel and a steel wheel from each other after calculating, through experiments and simulations, the inductance of the pattern member <NUM> in a case in which a steel wheel is used and the inductance of the pattern member <NUM> in a case in which an aluminum wheel is used. The transmitter controlling unit <NUM> executing the process of step S1 is a determining unit that determines the type of the wheel <NUM>. The determination result of step S1 is stored, for example, in the RAM of the memory unit 25b.

As shown in <FIG>, in step S2, the transmitter controlling unit <NUM> generates transmission data that includes wheel identification information. As shown in <FIG>, the transmitter controlling unit <NUM> generates the transmission data that includes a preamble, an ID code, and wheel identification information. That is, the transmitter controlling unit <NUM> generates transmission data, which includes the wheel identification information, in addition to the pressure data and the temperature data. In the present embodiment, the wheel identification information indicates the type of the wheel <NUM>. The wheel identification information is configured to cause the receiver controlling unit <NUM> to recognize the type of the wheel <NUM> to which a tire valve is attached. The wheel identification information is, for example, one-bit information. The value <NUM> of the wheel identification information indicates a steel wheel, and the value <NUM> of the wheel identification information indicates an aluminum wheel. The transmitter controlling unit <NUM> outputs the generated transmission data to the transmission circuit <NUM>. The transmission circuit <NUM> transmits the data signal obtained by modulating the transmission data to the receiver <NUM>. The transmitter controlling unit <NUM> executing the process of step S2 is a controlling unit that causes the transmission circuit <NUM> to transmit the transmission data.

When the receiver controlling unit <NUM> receives the transmission data in step S3 as shown in <FIG>, the receiver controlling unit <NUM> obtains the wheel identification information included in the transmission data. The receiver controlling unit <NUM> executing the process of step S3 is an obtaining unit that obtains the wheel identification information.

Next, if the wheel identification information is <NUM> in step S4, the receiver controlling unit <NUM> recognizes that the tire valve is attached to a steel wheel. If the wheel identification information is <NUM>, the receiver controlling unit <NUM> recognizes that the tire valve is attached to an aluminum wheel. The receiver controlling unit <NUM> sets a threshold in accordance with the type of the wheel <NUM>. In the present embodiment, the receiver controlling unit <NUM> transmits the threshold corresponding to the type of the wheel <NUM>, thereby setting a threshold used to control the ECU <NUM>.

As shown in <FIG>, the receiver memory unit 41b stores a correspondence relationship between the type of the wheel <NUM> and thresholds related to control of the vehicle <NUM>. The threshold of the present embodiment is an upper limit of the vehicle speed. When the wheel <NUM> is a steel wheel, a first vehicle speed threshold is set. When the wheel <NUM> is an aluminum wheel, a second vehicle speed threshold is set. The upper limit of the vehicle speed is the threshold of the maximum speed allowed for the vehicle <NUM>.

The first vehicle speed threshold is lower than the second vehicle speed threshold. Thus, the upper limit of the vehicle speed is set to be lower when a steel wheel is used as the wheel <NUM> than when an aluminum wheel is used as the wheel <NUM>. A maximum speed is set for the tire <NUM>. An aluminum wheel tends to mount a tire <NUM> of a high maximum speed as compared to a steel wheel. The reason for this is assumed to be the fact that if the diameter of the wheel <NUM> is the same, a steel wheel is heavier than an aluminum wheel. A tire <NUM> of a higher maximum speed has a lower aspect ratio. Accordingly, when a tire <NUM> of a higher maximum speed is used, while maintaining the outer diameter of the tire <NUM>, the diameter of the wheel <NUM> is increased. In such a case, if a steel wheel is used, the wheel <NUM> is excessively heavy. It is thus assumed that an aluminum wheel is used for a tire <NUM> of a high maximum speed. In the present embodiment, the upper limit of the vehicle speed is set on the assumption that if the wheel <NUM> is an aluminum wheel, a tire <NUM> of a higher maximum speed is attached to the wheel <NUM> than in a case in which a steel wheel is used. The receiver controlling unit <NUM> executing the process of step S4 is a setting unit that sets a threshold related to control of the vehicle <NUM> in accordance with the type of the wheel <NUM>.

The process from step S1 to step S4 may be executed when a predetermined condition is met, for example, when the standing time of the vehicle <NUM> reaches or exceeds a predetermined time. Alternatively, the process from step S1 to step S4 may be repeatedly executed while the vehicle <NUM> is traveling. The determination of whether the vehicle <NUM> is traveling and the detection of the standing time of the vehicle <NUM> can be performed by using, for example, the detection value of the acceleration sensor <NUM>.

An operation of the first embodiment will now be described.

The transmitter <NUM> transmits transmission data including wheel identification information. Accordingly, a threshold that corresponds to the type of the wheel <NUM> is set in the ECU <NUM>. The ECU <NUM> sets the upper limit of the vehicle speed in accordance with the type of the wheel <NUM>. The ECU <NUM> controls the vehicle <NUM> such that the vehicle speed does not exceed the upper limit of the vehicle speed. The ECU <NUM> may perform control in which the upper limit of the vehicle speed is shown on the display device that is visually recognizable by the occupants. In this manner, the ECU <NUM> is capable of performing various types of control by using the upper limit of the vehicle speed. The upper limit of the vehicle speed is set to different values according to the type of the wheel <NUM>. That is, the upper limit of the vehicle speed is set to a value suitable for the type of the wheel <NUM>.

The first embodiment has the following advantages.

(<NUM>-<NUM>) The transmitter controlling unit <NUM> is capable of causing the receiver controlling unit <NUM> to recognize the type of the wheel <NUM> by transmitting transmission data including the wheel identification information. The receiver controlling unit <NUM> sets a threshold related to control of the vehicle <NUM> in accordance with the type of the wheel <NUM>. The vehicle <NUM> can thus be controlled properly in accordance with the type of the wheel <NUM>.

(<NUM>-<NUM>) Since steel has a higher magnetic permeability than aluminum, the inductance of the pattern member <NUM> varies depending on whether an aluminum wheel or a steel wheel is used as the wheel <NUM>. The transmitter controlling unit <NUM> is capable of determining whether the wheel <NUM> is an aluminum wheel or a steel wheel based on the inductance of the pattern member <NUM>. As such, wheel identification information does not have to be written in the memory unit 25b of the transmitter <NUM> in advance.

(<NUM>-<NUM>) The pattern member <NUM> has the shape of a loop. As compared to a case in which the pattern member <NUM> is a linear member, the magnetic flux B is easily guided to the wheel <NUM>, so that the inductance of the pattern member <NUM> is easily changed.

(<NUM>-<NUM>) The loop plane S is orthogonal to the centrifugal direction of the wheel <NUM>. The magnetic flux B generated in the pattern member <NUM> is more easily guided to the wheel <NUM>, so that the inductance of the pattern member <NUM> is easily changed.

(<NUM>-<NUM>) The receiver controlling unit <NUM> recognizes the type of the wheel <NUM> from the wheel identification information obtained from the transmission data. The receiver controlling unit <NUM> is capable of setting a threshold corresponding to the type of the wheel <NUM> from the correspondence relationship between the recognized type of the wheel <NUM> and a threshold related to control of the vehicle <NUM>. The vehicle <NUM> can thus be controlled properly in accordance with the type of the wheel <NUM>.

(<NUM>-<NUM>) The receiver controlling unit <NUM> sets the upper limit of the vehicle speed to different values depending on whether the wheel <NUM> is a steel wheel or an aluminum wheel. The maximum speed of the tire <NUM> tends to vary depending on the type of the wheel <NUM> to which the tire <NUM> is attached. Thus, by setting the upper limit of the vehicle speed in accordance with the type of the wheel <NUM>, control that corresponds to the type of the wheel <NUM> can be performed.

A transmitter <NUM> according to a second embodiment will now be described.

The transmitter of the second embodiment is different from that of the first embodiment in the process executed by the transmitter controlling unit. The hardware configuration of the transmitter and the receiver is similar to the first embodiment. The process executed in the transmitter will now be described.

As shown in <FIG>, the transmitter controlling unit <NUM> determines the type of the wheel <NUM> in step S11. The determination of the type of the wheel <NUM> is the same as that of step S1 in the first embodiment. That is, determination is made as to whether the wheel <NUM> is a steel wheel or an aluminum wheel by using the inductance of the pattern member <NUM>, which is measured by the inductance measuring unit <NUM>. The transmitter controlling unit <NUM> determines the type of the wheel <NUM> by performing determination using the measured value of the inductance measuring unit <NUM>. The transmitter controlling unit <NUM> executing the process of step S11 is a determining unit that is configured to determine the type of the wheel <NUM>.

Subsequently, in step S12, the transmitter controlling unit <NUM> sets a threshold in accordance with the type of the wheel <NUM>. As in the first embodiment, the upper limit of the vehicle speed is used as the threshold. When the wheel <NUM> is a steel wheel, the transmitter controlling unit <NUM> sets the threshold to the first vehicle speed threshold. When the wheel <NUM> is an aluminum wheel, the transmitter controlling unit <NUM> sets the threshold to a second vehicle speed threshold. The transmitter controlling unit <NUM> executing the process of step S12 is a warning threshold setting unit.

In the subsequent step S13, the transmitter controlling unit <NUM> determines whether the detection value of the acceleration sensor <NUM> has exceeded the threshold set in step S12. In a case in which the threshold is set to the first vehicle speed threshold in step S12, it is determined whether the detection value of the acceleration sensor <NUM> has exceeded the first vehicle speed threshold. In a case in which the threshold is set to the second vehicle speed threshold in step S12, it is determined whether the detection value of the acceleration sensor <NUM> has exceeded the second vehicle speed threshold. The determination of step S13 may be performed by using the detection value [G] of the acceleration sensor <NUM> or by using the vehicle speed [km/h] that has been calculated from the detection value of the acceleration sensor <NUM>. When the determination of step S13 is performed by using the detection value [G] of the acceleration sensor <NUM>, the first vehicle speed threshold and the second vehicle speed threshold are set as values of the acceleration [G]. When the determination of step S13 is performed by using the vehicle speed [km/h] calculated from the detection value of the acceleration sensor <NUM>, the first vehicle speed threshold and the second vehicle speed threshold are set as values of the vehicle speed [km/h]. Since there is a correlation between the vehicle speed and the detection value of the acceleration sensor <NUM>, the vehicle speed and the acceleration are interchangeable.

If the determination result of step S13 is negative, the transmitter controlling unit <NUM> ends the process. If the determination result of step S14 is affirmative, the transmitter controlling unit <NUM> executes the process of step S14.

In step S14, the transmitter controlling unit <NUM> causes the transmission circuit <NUM> to perform a warning transmission. The warning transmission refers to transmission of a signal requesting a warning to the occupants to the receiver <NUM>. The signal includes, for example, a warning flag. The transmitter controlling unit <NUM> executing the process of step S14 is a warning transmission controlling unit.

The process of step S11 to step S14 is repeatedly executed at a predetermined control period. Alternatively, only the processes of step S13 and step S14 may be repeated after the threshold is set in the processes of step S11 and step S12. In this case, the processes of step S11 and step S12 may be executed again when a predetermined condition is met, for example, when the standing time of the vehicle <NUM> reaches or exceeds a predetermined time. The standing time of the vehicle <NUM> can be acquired by using, for example, the detection value of the acceleration sensor <NUM>.

When receiving a signal transmitted from the transmitter <NUM> through the warning transmission, the receiver controlling unit <NUM> of the second embodiment issues a warning by using the warning device <NUM> or a display device visually recognizable by the occupants. That is, in the second embodiment, the receiver controlling unit <NUM> does not set the threshold corresponding to the type of the wheel <NUM>.

The second embodiment has the following advantages.

(<NUM>-<NUM>) The transmitter controlling unit <NUM> sets the upper limit of the vehicle speed in accordance with the type of the wheel <NUM>. When the detection value of the acceleration sensor <NUM> exceeds the upper limit of the vehicle speed, the transmitter controlling unit <NUM> causes the transmission circuit <NUM> to perform the warning transmission. The receiver <NUM> is allowed to issue a warning in accordance with the type of the wheel <NUM>. The receiver <NUM> is allowed to issue a warning, which is one mode of the control of the vehicle <NUM>, in accordance with the type of the wheel <NUM>. The vehicle <NUM> can thus be controlled properly in accordance with the type of the wheel <NUM>.

(<NUM>-<NUM>) The receiver controlling unit <NUM> is capable of issuing a warning in accordance with the type of the wheel <NUM> without setting the upper limit of the vehicle speed corresponding to the type of the wheel <NUM>. Therefore, a warning can be issued in accordance with the type of the wheel <NUM>, while simplifying the software of the receiver controlling unit <NUM>.

The above-described embodiments may be modified as follows. The embodiments and the following modifications can be combined as long as the combined modifications remain technically consistent with each other.

In each of the embodiments, the memory unit 25b may store in advance wheel identification information corresponding to the type of the wheel <NUM> to which a tire valve is attached. The wheel identification information may be written in the memory unit 25b of the transmitter <NUM> when the transmitter <NUM> is produced or may be written in the memory unit 25b of the transmitter <NUM> using an external device such as a trigger device. In this case, the transmitter controlling unit <NUM> does not have to determine the type of the wheel <NUM> based on the detection value of the acceleration sensor <NUM>. That is, the transmitter <NUM> does not have to include a determining unit. In this case, the transmitter <NUM> does not have to include the inductance measuring unit <NUM> and the pattern member <NUM>.

In each of the embodiments, it suffices if the transmitter <NUM> includes at least one sensor that is capable of detecting at least one of the condition of the tire <NUM> and the condition of the road surface. That is, it suffices if the transmitter <NUM> includes at least one of the pressure sensor <NUM>, which is capable of detecting pressure as the condition of the tire <NUM>, the temperature sensor <NUM>, which is capable of detecting the temperature as the condition of the tire <NUM>, and the acceleration sensor <NUM>, which is capable of detecting the centrifugal acceleration acting on the tire <NUM> as the condition of the tire <NUM>. One example of the sensor that detects the condition of the road surface is the acceleration sensor <NUM>. One examples of the condition of the road surface is the friction coefficient of the road surface during traveling. The friction coefficient of the road surface can be calculated by detecting the acceleration of the vehicle <NUM> in the traveling direction and the lateral acceleration using the acceleration sensor <NUM>.

In each of the embodiments, there may be three or more types of the wheel <NUM>. In addition to a steel wheel and an aluminum wheel, the types of the wheel <NUM> may include a magnesium wheel and a plastic wheel. Further, the types of the wheel <NUM> may include different types of wheel made of the same material, such as different types of steel wheels or different types of aluminum wheels. In this case, the threshold related to control of the vehicle <NUM> is associated with each type of the wheel <NUM>.

In each of the embodiments, the control for causing the receiver controlling unit <NUM> to recognize the type of the wheel <NUM>, which is, for example, determination of the type of the wheel <NUM> by the transmitter <NUM>, or transmission of the transmission data including the wheel identification information, may be performed only when a specified condition is met. Likewise, the receiver controlling unit <NUM> may set the threshold corresponding to the type of the wheel <NUM> only when a specified condition is met. The specified condition may be a condition that the type of the tire valve is the snap-in valve <NUM>. The maximum speed that can be handled by the snap-in valve <NUM> is lower than that of the clamp-in valve <NUM>. Setting of the upper limit of the vehicle speed is thus important when the snap-in valve <NUM> is used as the tire valve. The specified condition may be a condition that the temperature is lower than a low temperature threshold or a condition that the temperature is higher than or equal to a high temperature threshold. The low temperature threshold is a threshold for detecting that the temperature is excessively low. The high temperature threshold is a threshold for detecting that the temperature is excessively high.

In each of the embodiments, the transmitter <NUM> may be attachable to a single type of tire valve. For example, the transmitter <NUM> may be configured to be attached only to the clamp-in valve <NUM>. Further, the transmitter <NUM> may be configured to be attached only to the snap-in valve <NUM>.

In each of the embodiments, the transmitter controlling unit <NUM> may perform determination using a method different from the method in the embodiments as long as the transmitter controlling unit <NUM> can determine whether the wheel <NUM> is a steel wheel or an aluminum wheel based on the inductance of the pattern member <NUM>. For example, in a state in which the transmitter <NUM> is not attached to the wheel assembly <NUM>, the transmitter controlling unit <NUM> measures the inductance of the pattern member <NUM> with the inductance measuring unit <NUM>. The transmitter controlling unit <NUM> stores the measured inductance in the memory unit 25b. The inductance of the pattern member <NUM> that is measured in a state in which the transmitter <NUM> is not attached to the wheel assembly <NUM> has not been affected by the wheel <NUM>. When determining the type of the wheel <NUM>, the transmitter controlling unit <NUM> measures the inductance of the pattern member <NUM> with the inductance measuring unit <NUM>, and compares the measured inductance with the inductance stored in the memory unit 25b. When the transmitter <NUM> is attached to the wheel assembly <NUM>, the inductance of the pattern member <NUM> is affected by the wheel <NUM>. If the measured inductance is higher than the inductance stored in the memory unit 25b by an amount greater than or equal to a threshold, the transmitter controlling unit <NUM> determines that the wheel <NUM> is a steel wheel. If the measured inductance is higher than the inductance stored in the memory unit 25b by an amount greater than or equal to a threshold, the transmitter controlling unit <NUM> determines that the wheel <NUM> is a steel wheel.

In each of the embodiments, the transmission antenna <NUM> may be used as the metal member. When a loop-shaped antenna is used as the transmission antenna <NUM>, the transmission antenna <NUM> can also be used as the loop-shaped metal member.

In each of the embodiments, the loop plane S does not need to be orthogonal to the centrifugal direction of the wheel <NUM>. That is, the pattern member <NUM> may be arranged in any manner as long as the inductance of the pattern member <NUM> can be changed by the wheel <NUM>.

In each of the embodiments, the metal member does not necessarily need to have a shape of a loop. For example, the metal member may be a linear pattern member provided on the substrate <NUM>.

In each of the embodiments, it suffices if the receiver controlling unit <NUM> sets a threshold for a device that is required to set a threshold corresponding to the type of the wheel <NUM>. That is, not only the ECU <NUM>, but also the receiver controlling unit <NUM>, may set the threshold that is used by the receiver controlling unit <NUM>.

In each of the embodiments, it suffices if the transmission data includes at least data for causing the receiver <NUM> to transmit the transmission data and the wheel identification information.

In each of the embodiments, the vehicle <NUM> may be a motorcycle or a vehicle having five or more wheel assemblies <NUM>.

In the first embodiment, the ECU <NUM> may be regarded as a part of a receiver. That is, any type of receiver can be employed as long as it includes a device having a function of receiving transmission data and a device that sets a threshold for controlling the vehicle <NUM> in accordance with the type of the wheel <NUM>. In this case, the memory unit <NUM> of the ECU <NUM> may store a correspondence relationship between the wheel identification information and the thresholds for controlling the vehicle <NUM>. The receiver controlling unit <NUM> may obtain the wheel identification information and send it to the ECU <NUM>, so that the ECU <NUM> sets the threshold for controlling the vehicle <NUM>. In this case, the memory unit <NUM> of the ECU <NUM> is the receiver memory unit, and the ECU <NUM> is the setting unit.

In the first embodiment, the wheel identification information may be information of two or more bits.

In the first embodiment, the threshold related to control of the vehicle <NUM> may be any threshold other than the upper limit of the vehicle speed as long as the threshold is preferably changed in accordance with the type of the wheel <NUM>. For example, the threshold may be a warning threshold for causing the receiver <NUM> issue a warning when the pressure of the tire <NUM> reaches or exceeds the threshold. The receiver controlling unit <NUM> sets a first warning threshold when the wheel <NUM> is a steel wheel, and the tire valve is the snap-in valve <NUM>. On the other hand, the receiver controlling unit <NUM> sets a second warning threshold when the wheel <NUM> is an aluminum wheel, and the tire valve is the clamp-in valve <NUM>. The first warning threshold is lower than the second warning threshold. The maximum pressure that can be handled by the snap-in valve <NUM> is lower than that of the clamp-in valve <NUM>. A steel wheel tends to be thinner at the part to which the tire valve is attached than an aluminum wheel, so that load tends to locally concentrate on the tire valve. A section of the snap-in valve <NUM> that is in contact with the wheel <NUM> is the body <NUM>, which is made of rubber. Thus, as compared to a case in which the snap-in valve <NUM> is attached to an aluminum wheel, the maximum pressure that can be handled tends to be lowered due to elastic deformation caused by concentration of load in a case in which the snap-in valve <NUM> is attached to a steel wheel.

The transmitter controlling unit <NUM> may include, in the transmission data, wheel identification information and valve identification information for allowing the receiver controlling unit <NUM> to recognize the type of the tire valve. In this case, the receiver memory unit 41b stores correspondence relationship between the warning threshold and the combination of the type of the tire valve and the type of the wheel <NUM>. When the valve identification information is included in the transmission data, the memory unit 25b of the transmitter controlling unit <NUM> may store the type of the tire valve that is attached to the transmitter <NUM>. Also, the transmitter controlling unit <NUM> may determine whether the tire valve to which the transmitter <NUM> is attached is the snap-in valve <NUM> or the clamp-in valve <NUM> based on the detection value of the acceleration sensor <NUM>. The centrifugal acceleration acting on the transmitter <NUM> increases in proportion to the vehicle speed. The tire valve contacts the mounting hole forming surface <NUM> to be supported by the wheel <NUM>. Accordingly, the section that is in contact with the mounting hole forming surface <NUM> serves as a support point onto which load is concentrated. When the tire valve is the clamp-in valve <NUM>, the metal valve stem <NUM> faces the mounting hole forming surface <NUM>. In contrast, when the tire valve is the snap-in valve <NUM>, the rubber body <NUM> faces the mounting hole forming surface <NUM>. Since the body <NUM> is more likely to be deformed than the valve stem <NUM>, the snap-in valve <NUM> is tilted in the radial direction of the wheel <NUM> due to elastic deformation of the body <NUM>. As a result, when the vehicle speed is increased, the transmitter <NUM> is tilted to shift outward in the radial direction of the wheel <NUM> as the distance from the snap-in valve <NUM> increases. Accordingly, the centrifugal acceleration detected by the acceleration sensor <NUM> is lower than the centrifugal acceleration acting on the transmitter <NUM>. That is, when the vehicle speed is increased, the detection value of the acceleration sensor <NUM> is lower in the transmitter <NUM> attached to the snap-in valve <NUM> than in the transmitter <NUM> attached to the clamp-in valve <NUM>. The transmitter controlling unit <NUM> calculates a predicted rotation period of the wheel <NUM> from the detection value of the acceleration sensor <NUM>, and compares the rotation period with the period of the gravitational acceleration component included in the detection value of the acceleration sensor <NUM>. If the difference between the predicted rotation period of the wheel <NUM> and the period of the gravitational acceleration component is in a permissible range, the transmitter controlling unit <NUM> determines that the tire valve is the clamp-in valve <NUM>. If the difference is out of the permissible range, the transmitter controlling unit <NUM> determines that the tire valve is the snap-in valve <NUM>. In this manner, the valve identification information can be included in the transmission data without storing the information of the tire valve in the memory unit 25b in advance.

If the transmitter <NUM> is used only for the snap-in valve <NUM>, the transmitter controlling unit <NUM> does not need to include the valve identification information in the transmission data. In this case, it suffices if the receiver memory unit 41b stores correspondence relationship between the type of the wheel <NUM> and the warning threshold. Thus, even if the transmission data does not include the valve identification information, the receiver controlling unit <NUM> can set the first warning threshold when the wheel <NUM> is a steel wheel, and the tire valve is a snap-in valve.

When the threshold is set to a warning threshold, the receiver controlling unit <NUM> recognizes the pressure of the tire <NUM> from the pressure data included in the transmission data. When the pressure of the tire <NUM> exceeds the warning threshold, the receiver controlling unit <NUM> issues a warning using the warning device <NUM>. Also, the receiver controlling unit <NUM> may recognize the pressure of the tire <NUM> from the pressure data included in the transmission data, and perform control in which a warning is shown on a display device that is visually recognizable by the occupants. In this manner, the receiver controlling unit <NUM> is capable of performing various types of control by using the warning threshold. Since the warning threshold is set to different values in correspondence with the type of the wheel <NUM>, the warning threshold is set to a value suitable for the type of the wheel <NUM>.

In the first embodiment, when the information indicating a steel wheel and the information indicating an aluminum wheel are both included in the wheel identification information included in the transmission data transmitted from each transmitter <NUM>, the receiver controlling unit <NUM> may set the upper limit of the vehicle speed to the lowest value. That is, the receiver controlling unit <NUM> sets the upper limit of the vehicle speed to the first vehicle speed threshold, which corresponds to a steel wheel. When the wheel identification information includes information indicating a steel wheel and information indicating an aluminum wheel, the wheel assembly <NUM> may have been replaced by a wheel assembly with a spare tire. If the wheel assembly <NUM> attached to the vehicle <NUM> and the wheel assembly with a spare tire have different types of the wheel <NUM>, the wheel identification information from the respective transmitters <NUM> includes information indicating different types of the wheels <NUM>.

In the first embodiment, the wheel identification information may indicate an aluminum wheel when having a value of <NUM>, and may indicate a steel wheel when having a value of <NUM>.

In the first embodiment, the wheel identification information may be any type of information as long as it is capable of causing the receiver controlling unit <NUM> to recognize the type of the wheel <NUM>. The wheel identification information may be information other than data that directly indicates the type of the wheel <NUM>. For example, the wheel identification information may be the value of the ID code, or the transmission interval of the data signal, or the method of calculating an error correction code or an error detection code.

When the value of the ID code is used as the wheel identification information, the ID code may be represented as a hexadecimal number. In this case, a group of the ID codes in which the value of the most significant digit is <NUM> to <NUM> is associated with a steel wheel. A group of the ID codes in which the value of the most significant digit is <NUM> to F is associated with an aluminum wheel. An ID code corresponding to the type of the wheel <NUM> is registered in the transmitter <NUM> depending on the type of the wheel <NUM> to which the transmitter <NUM> is attached. The correspondence relationship between the groups of the ID codes and the types of the wheel <NUM> is stored in the receiver memory unit 41b. The receiver controlling unit <NUM> is capable of recognizing the type of the wheel <NUM> from the ID code included in the transmission data.

When the transmission interval of the data signal is used as the wheel identification information, the transmitter controlling unit <NUM> changes the transmission interval of the data signal in accordance with the type of the wheel <NUM>. For example, the transmission interval of the data signal is made shorter when the wheel <NUM> to which the transmitter <NUM> is attached is a steel wheel than when the wheel <NUM> to which the transmitter <NUM> is attached is an aluminum wheel. The transmission interval of the data signal can be set using an external device such as a trigger device. The correspondence relationship between the transmission interval of the data signal and the types of the wheel <NUM> is stored in the receiver memory unit 41b. The receiver controlling unit <NUM> is capable of recognizing the type of the wheel <NUM> from the transmission interval of the transmission data.

When the method of calculating an error correction code or an error detection code is used as the wheel identification information, the transmitter controlling unit <NUM> changes the method of calculating the error correction code or the error detection code in accordance with the type of the wheel <NUM>. For example, the data used in the calculation of the error correction code is made different between when the wheel <NUM> to which the transmitter <NUM> is attached is a steel wheel and when the wheel <NUM> to which the transmitter <NUM> is attached is an aluminum wheel. The correspondence relationship between the method of calculating the error correction code and the types of the wheel <NUM> is stored in the receiver memory unit 41b. The receiver controlling unit <NUM> calculates the error correction code using two calculation methods: the calculation method corresponding to a steel wheel and the calculation method corresponding to an aluminum wheel. The receiver controlling unit <NUM> selects one of the error correction codes, which have been calculated by the two calculation methods. Specifically, the receiver controlling unit <NUM> selects the error correction code that matches the error correction code included in the transmission data. The receiver controlling unit <NUM> recognizes, as the wheel <NUM> to which the transmitter <NUM> is attached, the type of the wheel <NUM> that corresponds to the calculation method that has calculated the selected error correction code. Although an error correction code is used in the above-described example, the same applies to an error detection code.

In the second embodiment, identification of the type of the wheel <NUM> in step S11 may be performed by storing the types of wheel <NUM> in the memory unit 25b in advance and referring to the memory unit 25b.

Claim 1:
A transmitter (<NUM>) configured to be integrated with a tire valve (<NUM>, <NUM>) attached to a wheel (<NUM>), the transmitter (<NUM>) comprising:
a data generating unit (<NUM>) configured to generate transmission data;
a transmitting unit (<NUM>) configured to transmit the transmission data to a receiver (<NUM>), the receiver (<NUM>) including a setting unit (<NUM>) that sets a threshold related to control of a vehicle (<NUM>) in accordance with a type of the wheel (<NUM>); and
a controlling unit (<NUM>) configured to cause the transmitting unit (<NUM>) to transmit the transmission data, the transmission data including wheel identification information, wherein the wheel identification information is required by the setting unit (<NUM>) when setting the threshold and allows the setting unit (<NUM>) to recognize the type of the wheel (<NUM>) to which the tire valve (<NUM>, <NUM>) is attached,
characterized in that
the transmitter (<NUM>) further comprises:
a metal member (<NUM>) that is configured such that an inductance changes in accordance with the type of the wheel (<NUM>) to which the transmitter (<NUM>) is attached;
an inductance measuring unit (<NUM>) configured to measure the inductance of the metal member (<NUM>); and
a determining unit (<NUM>) configured to determine a type of the wheel (<NUM>) to which the transmitter (<NUM>) is attached based on the inductance of the metal member (<NUM>) measured by the inductance measuring unit (<NUM>).