A tire pressure monitoring apparatus includes a frequency detection unit configured to detect a resonant frequency according to a tire pressure; a calculation unit configured to accumulate the resonant frequency and calculate an average frequency and a frequency variance; a coordinate system setting unit configured to locate a first average variance point corresponding to the average frequency and the frequency variance, on an average-variance plane, and locate second average variance points corresponding to average frequencies and frequency variances of resonant frequencies measured for types of tires, on the average-variance plane; a tire determination unit configured to determine a type of a tire in consideration of distances between the first and second average variance points; and a low-pressure frequency setting unit configured to set a low-pressure frequency according to the determined type of the tire, as a reference low-pressure frequency for determining whether the tire pressure is a low pressure.

A tire pressure monitoring system including a monitoring unit positioned in a tractor, a first repeater positioned in the tractor, a plurality of second repeaters positioned in a plurality of trailers connected to the tractor, and a plurality of sensors positioned at tires of the tractor or the trailers. A first RF transceiving unit transceives data with the first repeater by a low power RF transmitting unit to the plurality of second repeaters.

A system for monitoring tire pressure of at least one vehicle tire of a utility vehicle includes a pressure sensor for detecting an internal tire pressure of the at least one vehicle tire and an electrically controllable tire inflation system for varying the internal tire pressure. The system also includes a monitoring unit disposed in communication with the pressure sensor and the tire inflation system. The monitoring unit identifies a defect-induced loss of pressure in the at least one vehicle tire based on the detected internal tire pressure, determines a temporal progression of the detected defect-induced loss of pressure, calculates a volume flow necessary for continuous compensation of the pressure loss based on the temporal progression, and controls the volume flow into the at least one vehicle tire via the tire inflation system.

A device for tire pressure monitoring of a vehicle tire of a vehicle system includes a tire inflation system in communication with the vehicle tire. A control unit calculates a set pressure value to be maintained for the tire pressure. A storage unit is in communication with the control unit such that the control unit adjusts the calculated set pressure value in dependence on an operating state classification derived from operating state parameters of the vehicle system. The control unit determines a geoposition of the vehicle system correlating with the derived operating state classification and stores it with the operating state classification in the storage unit. The control unit further recalls from the storage unit the relevant operating state classification for purposes of anticipatory adjustment of the set pressure value of the tire pressure when a renewed approach of the vehicle system to the stored geoposition is detected.

A rotary union for a tire inflation system of a heavy-duty vehicle that includes energy harvesting structure for generating electricity to power electronic components of the heavy-duty vehicle. The energy harvesting structure is integrated with and protected by the rotary union. The energy harvesting structure includes components that are attached to respective static and rotatable components of the rotary union that generate electricity for powering the electronic components during rotational movement of the rotatable components relative to the static components during operation of the heavy-duty vehicle. The components of the energy harvesting structure can be entirely removed or separated and sealed from a flow path of pressurized air through the rotary union.

A method for detecting a leak in a pressure vessel of a system including a plurality of pressure vessels in fluid communication with a common header comprises: reducing a fluid pressure in the common header to a first predetermined value below an operating pressure of the plurality of pressure vessels; gradually adding fluid to the common header at a first flow rate to increase the fluid pressure in the common header from the first predetermined value; monitoring, after gradually adding the fluid to the common header, the fluid pressure in the common header; and determining, based on the fluid pressure in the common header after gradually adding the fluid to the common header, a leak in at least one pressure vessel of the plurality of pressure vessels.

A rotary transmission device for transmitting control and/or working pressures to a wheel hub. The rotary transmission device has a housing structure in which a piston element is displaceable between a first and a second position relative to the housing structure and relative to a running body of the wheel hub which is mounted so as to rotate relative to the housing structure. To transmit the control and/or working pressures, at least one pressure medium channel is formed in the piston element. In the first position, an air gap is present between an end face of the piston element on the running body side and an end face of the running body on the piston element side, while in the second position, no air gap is present, and the at least one pressure medium channel opens in sealed fashion into at least one pressure medium channel formed in the running body.

A rotary transmission device for transmitting control and/or working pressures to a wheel hub. The rotary transmission device has a housing structure in which a piston element is displaceable between a first and a second position relative to the housing structure and relative to a running body of the wheel hub which is mounted so as to rotate relative to the housing structure. To transmit the control and/or working pressures, at least one pressure medium channel is formed in the piston element. In the first position, an air gap is present between an end face of the piston element on the running body side and an end face of the running body on the piston element side, while in the second position, no air gap is present, and the at least one pressure medium channel opens in sealed fashion into at least one pressure medium channel formed in the running body.

The invention relates to a rotary transmission apparatus (1) for the transmission of control and/or working pressures to a fluid duct (51) which is received or configured at least in regions in the interior of a shaft (50), in particular a drive shaft. The rotary transmission apparatus (1) has a stator assembly (2) which is arranged in a stationary manner with respect to a rotational movement of the shaft (50) and has at least one fluid feed/discharge line (3) and a control element (4) which can be displaced in the shaft longitudinal direction (L) relative to the shaft (50) between a first position and a second position. A flow connection between the at least one fluid feed/discharge line (3) and the fluid duct (51) is interrupted in the first position of the control element (4), and a flow connection between the at least one fluid feed/discharge line (3) and the fluid duct (51) is established in the second position of the control element (4).

A real time tire pressure sensing system includes sensors to collectively generate signals corresponding to a contained tire air temperature, a contained inflation pressure, and an ambient temperature associated with a tire mounted on a vehicle. A processor determines an effective tire inflation pressure based on the generated signals and further at least on a calculated moving average of the ambient temperature (e.g., over a defined time period such as 24 hours) and generates real time notifications associated with the determined effective tire inflation pressure to specified user interfaces. At least one sensor may be an inflation pressure sensor configured to generate event-based signals corresponding to detected changes per unit pressure. The processor may further generate real time feedback control signals to an automatic tire inflation device, based on the determined effective tire inflation pressure, or enable and prompt manual control of the tire inflation device via the user interface.