A speed controller capable of controlling an action speed of an external cylinder in one stroke in a step-wise manner. The speed controller includes a first flow path and a second flow path that allow a first port and a second port to be in communication with each other. The first flow path is provided with a first check valve for allowing flow from the first port to the second port. The second flow path is provided with a first needle valve, and an opening hole of the first check valve is constituted as a part of a flow path. The first needle valve adjusts the flow rate by changing an opening area of the opening hole with a tip portion fixed on a piston in the cylinder chamber. The speed controller further includes a third flow path allowing the first port and the cylinder chamber to be in communication with each other. The third flow path is provided with a second check valve for allowing flow from the first port to the cylinder chamber.

A hydraulic drive system (1) including a meter-in compensator (37) and a bleed-off compensator (42) comprises a plurality of sensors (64 to 68), a controller (62), and an outlet pressure switching valve (61). The controller (62) determines whether or not the state of a wheel loader (2) which is detected based on the signals output from the sensors (64 to 68) meets a predetermined steering limiting condition. When the controller (62) determines that the state of the wheel loader (2) meets the steering limiting condition, it outputs a command signal to the outlet pressure switching valve (61). The outlet pressure switching valve (61) reduces the flow rate of the hydraulic oil flowing to steering cylinders (18L, 18R), in response to the command signal in such a manner that the flow rate becomes lower than that corresponding to the operation amount of a handle of a steering device (35).

A hydraulic drive system (1) including a meter-in compensator (37) and a bleed-off compensator (42) comprises a plurality of sensors (64 to 68), a controller (62), and an outlet pressure switching valve (61). The controller (62) determines whether or not the state of a wheel loader (2) which is detected based on the signals output from the sensors (64 to 68) meets a predetermined steering limiting condition. When the controller (62) determines that the state of the wheel loader (2) meets the steering limiting condition, it outputs a command signal to the outlet pressure switching valve (61). The outlet pressure switching valve (61) reduces the flow rate of the hydraulic oil flowing to steering cylinders (18L, 18R), in response to the command signal in such a manner that the flow rate becomes lower than that corresponding to the operation amount of a handle of a steering device (35).

A pneumatic device having a pneumatic cylinder and a piston movably mounted in the pneumatic cylinder to divide an interior of the pneumatic cylinder into two chambers. The chambers are connected to a line network having a valve assembly. The line network, in a plurality of operating states of the valve assembly serving for venting the respective chamber, connects the respective chamber to at least a respective selected one of a plurality of outflow openings, of the pneumatic device, and in a further operating state of the valve assembly, disconnects the respective chamber from the outflow opening. A control installation of the pneumatic device adjusts the operating state of the valve assembly. The line network is designed so that, in at least three of the operating states for venting the respective chamber, the connection between the respective chamber and the outflow opening is established by mutually dissimilar flow resistances.

A movement apparatus for industrial automation, in particular for handling a workpiece, including: a fluidic actuator to which a pressurised fluid can be applied, with a actuator element, and a pressurised fluid provision device which is designed to apply the pressurised fluid to the fluidic actuator according to a control signal, in order to move the actuator element into a predefined position. The pressurised fluid provision device is designed to, whilst the actuator element is in movement to the predefined position, successively change a pressure of the pressurised fluid and/or a throttle opening which is used for providing the pressurised fluid, according to a predefined value course, in order to adapt the movement of the actuator element.

A movement apparatus for industrial automation, in particular for handling a workpiece, including: a fluidic actuator to which a pressurised fluid can be applied, with a actuator element, and a pressurised fluid provision device which is designed to apply the pressurised fluid to the fluidic actuator according to a control signal, in order to move the actuator element into a predefined position. The pressurised fluid provision device is designed to, whilst the actuator element is in movement to the predefined position, successively change a pressure of the pressurised fluid and/or a throttle opening which is used for providing the pressurised fluid, according to a predefined value course, in order to adapt the movement of the actuator element.

In some applications, a piston of a hydraulic actuator may move at high speeds, and large undesired forces may be generated if the piston reaches an end-stop of the hydraulic actuator at a high speed. The undesired forces may, for example, cause mechanical damage in the hydraulic actuator. A controller may receive information indicative of the piston reaching a first position at a first threshold distance from the end-stop, and, in response, may modify a signal to a valve assembly controlling flow of hydraulic fluid to and from the hydraulic actuator. Further, the controller may receive information indicative of the piston reaching a second position at a second threshold distance closer to the end-stop of the hydraulic actuator, and, in response, the controller may further modify the signal to the valve assembly so as to apply a force on the piston in a away from the end-stop.

In some applications, a piston of a hydraulic actuator may move at high speeds, and large undesired forces may be generated if the piston reaches an end-stop of the hydraulic actuator at a high speed. The undesired forces may, for example, cause mechanical damage in the hydraulic actuator. A controller may receive information indicative of the piston reaching a first position at a first threshold distance from the end-stop, and, in response, may modify a signal to a valve assembly controlling flow of hydraulic fluid to and from the hydraulic actuator. Further, the controller may receive information indicative of the piston reaching a second position at a second threshold distance closer to the end-stop of the hydraulic actuator, and, in response, the controller may further modify the signal to the valve assembly so as to apply a force on the piston in a away from the end-stop.

A two-stage speed controller includes a main body including a first port and a second port in communication with each other, and a primary channel and a secondary channel for fluid to flow therethrough. The secondary channel allows flowing in a single direction to a pressure accumulation chamber. A sliding-axle seat is arranged in the second port. An end of a sliding axle assembly forms, together with the sliding-axle seat, a valve. The pressure accumulation chamber is connected with a primary throttle channel. The sliding axle assembly is formed, in a transverse direction, with a secondary throttle channel. During ingress and discharging of the fluid, all the channels and movement of the valve together allow for control of the pressure of the fluid according to a magnitude of a spring force of a regulation assembly in order to control a moving speed of a cylinder connected to the main body.

A two-stage speed controller includes a main body including a first port and a second port in communication with each other, and a primary channel and a secondary channel for fluid to flow therethrough. The secondary channel allows flowing in a single direction to a pressure accumulation chamber. A sliding-axle seat is arranged in the second port. An end of a sliding axle assembly forms, together with the sliding-axle seat, a valve. The pressure accumulation chamber is connected with a primary throttle channel. The sliding axle assembly is formed, in a transverse direction, with a secondary throttle channel. During ingress and discharging of the fluid, all the channels and movement of the valve together allow for control of the pressure of the fluid according to a magnitude of a spring force of a regulation assembly in order to control a moving speed of a cylinder connected to the main body.