A main tank storing pressurized air supplied to a pair of air springs; an air supply passage through which the pressurized air flows between the main tank and each of the pair of air springs; a plurality of compressors configured to supply the pressurized air to the main tank; an air discharge passage which is connected to the pair of air springs and through which discharged pressurized air discharged from the air springs flows; and an exhaust tank connected to the air discharge passage and storing the discharged pressurized air discharged from the air springs, the plurality of compressors including at least one first compressor configured to pressurize air introduced from an atmosphere and at least one second compressor configured to operate auxiliarily for an operation of the first compressor and pressurize the discharged pressurized air introduced from the exhaust tank.

A main tank storing pressurized air supplied to a pair of air springs; an air supply passage through which the pressurized air flows between the main tank and each of the pair of air springs; a plurality of compressors configured to supply the pressurized air to the main tank; an air discharge passage which is connected to the pair of air springs and through which discharged pressurized air discharged from the air springs flows; and an exhaust tank connected to the air discharge passage and storing the discharged pressurized air discharged from the air springs, the plurality of compressors including at least one first compressor configured to pressurize air introduced from an atmosphere and at least one second compressor configured to operate auxiliarily for an operation of the first compressor and pressurize the discharged pressurized air introduced from the exhaust tank.

An actuator unit includes two chambers defined in the cylinder; a supply passage allowing a working fluid discharged from the pump to be supplied to the two chambers; a discharge passage allowing the two chambers to communicate with the tank; a direction control valve configured to selectively communicate each of the two chambers with one of the pump and the tank; a control passage that branches from the supply passage on a side of the pump rather than the direction control valve so as to communicate the pump with the tank; a variable relief valve provided on the control passage, the variable relief valve opening so as to allow the working fluid to flow from the supply passage toward the tank when a pressure in the supply passage reaches the valve opening pressure; and a center passage that communicates the tank with an interior of the cylinder.

An actuator unit includes two chambers defined in the cylinder; a supply passage allowing a working fluid discharged from the pump to be supplied to the two chambers; a discharge passage allowing the two chambers to communicate with the tank; a direction control valve configured to selectively communicate each of the two chambers with one of the pump and the tank; a control passage that branches from the supply passage on a side of the pump rather than the direction control valve so as to communicate the pump with the tank; a variable relief valve provided on the control passage, the variable relief valve opening so as to allow the working fluid to flow from the supply passage toward the tank when a pressure in the supply passage reaches the valve opening pressure; and a center passage that communicates the tank with an interior of the cylinder.

A friction shoe for a railway car truck is provided. The railway truck comprises two parallel side frames, a suspension spring assembly supported by the side frames, and a bolster transversely mounted between the side frames and supported by the suspension spring assembly. Each side frame has at least one vertical support face, and the bolster has at least one sloped support face.

The friction shoe comprises a bottom base engaging and supported by a support spring, and a sloped wall engaging the sloped support face of the bolster.

The present invention includes geometric improvements in friction shoe design which prevent bolster side wall wear and helps eliminate the possibility of the friction shoe's wear on the bolster side wall from interfering with its normal movement over its service life.

A friction shoe for a railway car truck is provided. The railway truck comprises two parallel side frames, a suspension spring assembly supported by the side frames, and a bolster transversely mounted between the side frames and supported by the suspension spring assembly. Each side frame has at least one vertical support face, and the bolster has at least one sloped support face.

The friction shoe comprises a bottom base engaging and supported by a support spring, and a sloped wall engaging the sloped support face of the bolster.

The present invention includes geometric improvements in friction shoe design which prevent bolster side wall wear and helps eliminate the possibility of the friction shoe's wear on the bolster side wall from interfering with its normal movement over its service life.

An actuator unit includes a rod side chamber and a piston side chamber defined in the cylinder by a piston; a tank; a direction control valve configured to allow a working fluid discharged from the pump to be supplied selectively to the rod side chamber and the piston side chamber; a first control passage that communicates the rod side chamber with the tank; a second control passage that communicates the piston side chamber with the tank; a first variable relief valve provided on the first control passage, the first variable relief valve being configured to have a varied valve opening pressure; a second variable relief valve provided on the second control passage, the second variable relief valve configured to have a varied valve opening pressure; and a center passage that communicates the tank with the interior of the cylinder.

A leveling valve includes: a seat portion configured to define a flow passage, the flow passage communicating with the air cushion and a compressed air source or communicating with the air cushion and a drain; a valve configured to move in an axial direction in accordance with a relative displacement of the vehicle body with respect to the truck; a spring configured to bias the valve toward a closing side, the valve being in contact with the seat portion in the closing side; a valve guide configured to support one end of the spring, the valve guide being slidably inserted with respect to a housing inner wall surface; and a communication port opened to the housing inner wall surface. A moving region in which the valve guide moves is set to a position offset from the communication port in the axial direction.

A leveling valve includes: a seat portion configured to define a flow passage, the flow passage communicating with the air cushion and a compressed air source or communicating with the air cushion and a drain; a valve configured to move in an axial direction in accordance with a relative displacement of the vehicle body with respect to the truck; a spring configured to bias the valve toward a closing side, the valve being in contact with the seat portion in the closing side; a valve guide configured to support one end of the spring, the valve guide being slidably inserted with respect to a housing inner wall surface; and a communication port opened to the housing inner wall surface. A moving region in which the valve guide moves is set to a position offset from the communication port in the axial direction.

The disclosure relates to a valve assembly and a method for controlling the air suspension level of a rail vehicle. A system is provided, which is constructionally simple to build and easy to parameterise, for controlling the air suspension level of a rail vehicle. The object of the disclosure is achieved by a valve assembly for controlling the air suspension level of a rail vehicle, comprising a proportional directional valve, a sensor means for continuously detecting a distance variable representing the distance of a carriage body from a chassis or bogie of the rail vehicle, and a digital control device, wherein the control device is designed to be programmable for determining a control deviation based on the actual distance detected by the sensor means and a comparison with a predefinable target distance, and for continuously generating control variables as a linear function of the determined control deviation and the carriage body travelling speed. The object is also achieved by a method for controlling the air suspension level of a rail vehicle with a proportional directional valve, a sensor means for continuously detecting a distance variable representing the distance of the carriage body from a chassis or bogie, and a digital control device, wherein a control deviation is determined by the control device based on a comparison of the actual distances detected by the sensor means with a predefinable target distance, and a control variable is generated continuously as a linear function of the determined control deviation and the carriage body travelling speed.