A manifold type solenoid valve comprises a main valve section and a solenoid operating section. The main valve section has a spool in a valve hole to which respective switching flow paths for supply, output, and discharge are opened.

The main valve section comprises connecting flow paths for collective supply and/or collective discharge having connecting ports, output ports, and an external port for connecting an external piping for independent supply or independent discharge. The output ports are in communication with the switching flow path for output. The connecting flow paths for collective supply and/or collective discharge are in communication with the switching flow path for supply and the switching flow path for discharge. Additionally, the external port is in communication with the switching flow path for supply or the switching flow path for discharge.

A technology to connect a plurality of solenoid valves and use in a form of a solenoid valve assembly is publicly known in the related art as disclosed, for example, in Patent Document 1. The solenoid valve assembly of this type generallyemploys a collective piping system and is configured in such a manner that pressure fluid is supplied from a supply and exhaust block built in the assembly collectively to the respective solenoid valves via connecting flow paths which communicate thesolenoid valves with respect to each other, or exhaust fluid is discharged from the respective solenoid valves collectively.

However, in the solenoid valve assembly in the related art as described above, only fluid of the same pressure can be supplied through the supply and discharge block to the respective solenoid valves. In order to supply fluid of differentpressure to some of the solenoid valves, it is necessary to provide the plurality of supply and discharge blocks for each pressure and bring them into communication with these solenoid valves, and hence the length of the solenoid valve assembly increasescorrespondingly, and the apparatus is upsized. It is the same when exhaust fluid is separately discharged from some solenoid valves. Therefore, development of a solenoid valve of a structure which can solve such a problem is expected.

It is an object of the present invention is to provide a manifold type solenoid valve, which has both functions of collective piping and independent piping, and hence enables such usages as supplying fluid at different pressure fromfluid supplied through the collective piping or discharging exhaust fluid differently from the collective piping by being built in the solenoid valve assembly without using a plurality of supply and discharge blocks, whereby superior functionality isachieved.

According to a detailed structure of the present invention, the housing includes one connecting flow path of both-way connecting type having the connecting ports opening on both left and right side surfaces of the housing, the connecting flowpath is in communication with any one of the switching flow paths for supply or discharge, and the external port is directly in communication with the other switching flow path without intermediary of the connecting flow path.

In this case, it is also applicable that the housing further includes a direct flow path of both-way connecting type having the connecting ports opening on both left and right side surfaces of the housing, and the direct flow path may be blockedboth from the switching flow path and from the external port.

According to another detailed structure of the present invention, the housing includes one each of the connecting flow path of both-way connecting type having the connecting ports opening on both left and right side surfaces of the housing, andthe connecting flow path of one-way connecting type having an connecting port opening on one side surface, and the connecting flow paths are in communication with one of the switching flow paths for supply and for discharge, respectively, and theexternal port is in communication with the connecting flow path of one-way connecting type, and the connecting port of the connecting flow path of one-way connecting type can be blockaded by a lid member.

According to another detailed structure of the present invention, the housing includes two connecting flow paths of both-way connecting type having the connecting ports opening on both left and right side surfaces of the housing, and theconnecting flow paths are in communication with one of the switching flow paths for supply and for discharge respectively, the external port is in communication with one of the connecting flow paths, and at least one of the connecting ports of theconnecting flow path in communication with the external port, which are opened on both side surfaces of the housing, can be blockaded by the lid member.

In the present invention, preferably, the housing of the main valve section is composed of a plurality of blocks, and a bottom block as one of these blocks is provided with the connecting flow path, and the external port is in communication withthe switching flow path via the bottom block, so that the function of the external port can be changed to supplying function or discharging function by replacing the bottom block by the one having the connecting flow path which provides differentconnection between the external port and the switching flow path.

Furthermore, in the present invention, it is also possible that the output port and the external port are formed on the port block which is the other one of the blocks constituting the housing, or alternatively, that the output port is formed onthe port block which is the other one of the blocks constituting the housing, and the external port is formed on the bottom block.

Since the manifold type solenoid valve of the present invention has both functions of collecting piping and independent piping by providing the external port, and hence enables such usage as supplying fluid at different pressure from fluidsupplied from the external port through the collective piping or discharging exhaust fluid differently from the collective piping by being built in the solenoid valve assembly without using the plurality of supply and discharge blocks, thereby beingsuperior in functionality.