An optical measurement device is disclosed and includes a body configured to be mounted to at least one piston cylinder, and a compression ratio determination unit operatively connected to the body to receive optical measurement data and compute a clearance between at least two opposed pistons disposed within the at least one piston cylinder.

An optical measurement device is disclosed and includes a body configured to be mounted to at least one piston cylinder, and a compression ratio determination unit operatively connected to the body to receive optical measurement data and compute a clearance between at least two opposed pistons disposed within the at least one piston cylinder.

The present application discloses a testing device and a testing method for multiple piston assembly of a cam-lobe hydraulic motor. N cylinder blocks are installed on the cylinder block base, and piston assemblies to be tested are installed on the cylinder blocks. A driving plate is installed on the cylinder block base, and N uniformly-distributed driving plate clamping grooves are formed in the driving plate. A cylinder block protrusion is arranged at the bottom of each cylinder block, and the cylinder block protrusions are clamped in the driving plate clamping grooves. When the driving plate is rotated, the N driving plate clamping grooves drive the N cylinder blocks to rotate synchronously through the cylinder block protrusions, to synchronously change the pressure angle between a driving shaft and each piston assembly.

The present application discloses a testing device and a testing method for multiple piston assembly of a cam-lobe hydraulic motor. N cylinder blocks are installed on the cylinder block base, and piston assemblies to be tested are installed on the cylinder blocks. A driving plate is installed on the cylinder block base, and N uniformly-distributed driving plate clamping grooves are formed in the driving plate. A cylinder block protrusion is arranged at the bottom of each cylinder block, and the cylinder block protrusions are clamped in the driving plate clamping grooves. When the driving plate is rotated, the N driving plate clamping grooves drive the N cylinder blocks to rotate synchronously through the cylinder block protrusions, to synchronously change the pressure angle between a driving shaft and each piston assembly.

Control system (1) comprising a control rod (5) extending between a first zone (2) situated in a hydraulic chamber delimited by a chamber wall (3) and a second zone (4) situated outside the hydraulic chamber. The control system (1) further comprising a seal (6) arranged around and against this control rod (5) to oppose the passage of fluid between the first and second zones (2, 4). The system further comprises a guide piece (7) assembled removably with respect to the chamber wall (3), the seal (6) is assembled inside the guide piece (7) so as to allow relative movement of the rod (5) with respect to the guide piece (7) while at the same time achieving sealing between the first and second zones (2, 4).

An internal combustion engine includes: a crankcase that supports a crankshaft rotatably about a rotational axis; a cylinder block connected with the crankcase and including at least one pair of cylinders that sandwich a valve chamber therebetween in an axial direction of the crankshaft, the valve chamber housing therein a valve actuating mechanism that connects a camshaft to the crankshaft; a detected member disposed between crank pins corresponding to the pair of cylinders, the detected member rotating integrally with the crankshaft; and a detection sensor disposed to face a trajectory of the detected member and generating a pulse signal in accordance with movement of the detected member. Accordingly, the internal combustion engine can avoid displacement of a nearby part and enlargement of the crankcase as much as possible, while allowing the detected member to be increased in size.

Methods and systems for a hydraulic unit. In one example, a hydraulic unit includes a torque sensor external mounted to a housing of the hydraulic unit, wherein a torque sensor mount is physically coupled to a planar portion of the housing near a flange through which a drive shaft extends.

A free piston device, comprises a housing with a cylindrical inner wall having a first wall opening and a second wall opening; a cylindrical piston movable in axial direction and rotatable around its longitudinal axis; the piston comprising a first skirt forming a first chamber, said first skirt having at least a first opening in the form of a hole through the wall of the skirt for allowing passage of a fluid directly into or out of said chamber; control means for controlling axial and angular movement of said piston; sensing means for providing signals related to the axial position and/or the angular position of the piston; a digital control unit for rotating the piston around its longitudinal axis in synchronism with its axial movement.

A free piston device, comprises a housing with a cylindrical inner wall having a first wall opening and a second wall opening; a cylindrical piston movable in axial direction and rotatable around its longitudinal axis; the piston comprising a first skirt forming a first chamber, said first skirt having at least a first opening in the form of a hole through the wall of the skirt for allowing passage of a fluid directly into or out of said chamber; control means for controlling axial and angular movement of said piston; sensing means for providing signals related to the axial position and/or the angular position of the piston; a digital control unit for rotating the piston around its longitudinal axis in synchronism with its axial movement.

A fluid pressure cylinder includes a cylinder tube, a piston rod, and a displacement sensor. A bottom portion of the cylinder tube has: a pin hole formed in a direction orthogonal to a center axis; and a through hole penetrating the bottom portion through the pin hole. The displacement sensor has: a sensor body disposed on inner side of the pin hole in the through hole; a sensor rod provided so as to extend from the sensor body; and an annular magnet relatively movable with respect to the sensor rod. The through hole has: a reduced-diameter portion; and a female screw portion that has a female screw formed on an inner circumference of the female screw portion. The sensor body is fixed by being pressed by a plug that is screwed into the female screw portion and by being engaged with the reduced-diameter portion.