Abstract: A first fluid circuit is a fluid circuit of an air cylinder provided with an air cylinder with a first air chamber and a second air chamber that are defined by a piston; a switching valve that is switched between the drive step and return step of the piston; a first flow channel between the first air chamber and the switching valve; and a second flow channel between the second air chamber and the switching valve. Two speed control valves are provided in series in the second flow channel.

Abstract: A selection system for hydraulic circuits has a cylinder selection processing unit; a database in which information pertaining to a combination of a plurality of apparatuses is registered in advance; combination selection processing units for reading information pertaining to the combination of the plurality of apparatuses in order of size from the database, and selecting an apparatus; and re-selection processing units for re-selecting an apparatus that is the next size up when a stroke time obtained by a simulation including some of the apparatuses selected by the combination selection unit exceeds an upper-limit stroke time, or when pressure after a return process is less than or equal to minimum working pressure.

Abstract: A first fluid circuit is a fluid circuit of an air cylinder provided with an air cylinder with a first air chamber and a second air chamber that are defined by a piston; a switching valve that is switched between the drive step and return step of the piston; a first flow channel between the first air chamber and the switching valve; and a second flow channel between the second air chamber and the switching valve. Two speed control valves are provided in series in the second flow channel.

Abstract: An air cylinder fluid circuit is formed by connecting a switching valve, which switches the supply and discharge of compressed air, and cylinder port parts of an air cylinder by means of pipes, wherein the acoustic velocity conductance of the pipes is smaller than the acoustic velocity conductance of the switching valve and the cylinder port parts.