Patent Publication Number: US-6907902-B2

Title: Hydraulic signal output device

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a hydraulic signal output device that outputs a hydraulic signal in accordance with a manual operation to an external actuator. 
   2. Description of the Related Art 
   An operation room of a hydraulic shovel is provided with a pilot pressure oil output device that outputs pilot pressure oil in accordance with an operation of such as an operation lever. When an operator tilts the operation lever fore and aft, from side to side, and obliquely, a movement of a vehicle can be controlled. 
     FIG. 20  shows an operator&#39;s seat  100  disposed in an operation room. Sideward to the operator&#39;s seat  100 , a lever stand  80  is disposed. The lever stand  80  is provided with a hydraulic signal output device constituted of a PPC valve. An operation lever  7  is attached to the hydraulic signal output device and disposed so as to project upward from the lever stand  80 .  FIGS. 21A through 21C  are a side view, a plan view and a bottom view, respectively, of a hydraulic signal output device  50  to which the operation lever  7  is attached, and as shown in these drawings the hydraulic signal output device  50  is accommodated in the lever stand  80 . 
     FIG. 12  is a sectional view of a hydraulic signal output device having an operation lever. In the hydraulic signal output device  50 , when a single operation lever is tilted, each of four pistons outputs outside a hydraulic signal in accordance with its displacement, specifically pilot pressure oil is outputted. When the operation lever is tilted, the pilot pressure oil is outputted, the outputted pilot pressure oil is guided to a not shown operation valve, and thereby an operation valve is operated. When the operation valve is controlled, a hydraulic motor that makes a vehicle run or a hydraulic cylinder that operates an operating machine is controlled in their movement. The hydraulic signal output device  50  is called a PPC valve. 
   Furthermore, in some cases, a hydraulic signal output device that outputs pilot pressure oil in accordance with an electrical signal is disposed. When an operation is carried out in, for instance, a dangerous spot, it is dangerous for an operator to ride and operates a vehicle. In such a case, an operator operates a remote control device externally of the operation room and sends a radio signal to the hydraulic signal output device. Based on the received signal, a current flows in the hydraulic signal output device, and the pilot pressure oil in accordance with a magnitude of the signal is outputted. 
     FIG. 13  is a sectional view of a hydraulic signal output device that outputs pilot pressure oil in accordance with an electrical signal. A hydraulic signal output device  60  outputs pilot pressure oil in accordance with a thrust force of a plunger  26 . The hydraulic signal output device  60  is disposed corresponding to each of pistons of the hydraulic signal output device  50 . Accordingly, when the hydraulic signal output device  60  is remote-controlled, a movement of a hydraulic motor that makes a vehicle run is controlled. The hydraulic signal output device  60  is called a proportional EPC valve, and a thrust force that is proportional to a magnitude of a current that flows in a solenoid coil  25  acts in an arrow mark U direction. 
   As shown in  FIG. 14 , in the case of the PPC valve  50  and the EPC valve  60  being provided to an operation room of a vehicle, a shuttle valve  30  that connects the PPC valve  50  and the EPC valve  60  is disposed. 
   The shuttle valve  30  outputs the pilot pressure oil of a higher-pressure one of the PPC valve  50  and the EPC valve  60 . The pilot pressure oil is input into an operation valve that controls pressure oil that is supplied to the hydraulic motor. Accordingly, when the operator operates the operation lever or the remote-control device, a vehicle is made run or the operating machine is made to operate. 
   However, when the PPC valve  50 , the EPC valve  60  and the shuttle valve  30  are disposed separately in the operation room, there is necessity of connecting between these PPC valve  50 , EPC valve  60  and shuttle valve  30  through a pipe line such as a hose and so on, resulting in a large installation space. Accordingly, there is a problem in that a space other than the hydraulic machines in the operation room becomes relatively smaller. 
   The present invention is carried out in view of such situations and a first object of the present invention is to provide a hydraulic signal output device having a smaller installation space, and thereby making the installation space of the hydraulic machines in the operation room relatively smaller and thereby making a space other than the hydraulic machines relatively larger. 
   In some cases, however, the operator may manually operate wrongly and allow the vehicle to intrude into a dangerous spot. In this case, the operator is mostly not aware of the vehicle having intruded into the dangerous spot. At the time of such wrong operation being performed, unless some measures are not applied from the outside, the vehicle is allowed to intrude into a further dangerous spot. 
   Furthermore, in some cases, an operator unfamiliar to the operation of the PPC valve  50  may not move the vehicle as he wants. 
   The present invention is carried out in view of these situations, and a second object of the present invention is to allow externally limiting the operation in the operation room. 
   Actually, a shape of the lever stand  80  shown in  FIG. 20  can be various because of the restrictions resulting from a layout of the operation room. Accordingly, depending on the shape of the lever stand  80 , different from one that is shown in  FIG. 21 , the hydraulic signal output device  50  may not be accommodated inside of the lever stand  80 . 
   The present invention is carried out in view of such situations and a third object of the present invention is to allow the lever stand  80 , irrespective of the shape thereof, to accommodate the hydraulic signal output device therein. 
   SUMMARY OF THE INVENTION 
   In order to attain the first object, according to a first invention, a hydraulic signal output device includes: 
   manual hydraulic signal output means ( 50 ) for outputting a hydraulic signal based on a manual operation; 
   electrical hydraulic signal output means ( 60 ) for outputting a hydraulic signal based on an electrical signal; and 
   selection output means ( 30 ) for selecting and externally outputting either one of the hydraulic signal outputted from the manual hydraulic signal output means ( 50 ) or the hydraulic signal outputted from the electrical hydraulic signal output means ( 60 ); 
   wherein the manual hydraulic signal output means ( 50 ), the electrical hydraulic signal output means ( 60 ) and the selection output means ( 30 ) are integrally formed. 
   According to the first invention, a PPC valve  50 , an EPC valve  60  and a shuttle valve  30  are integrally formed. Accordingly, there is no need of connecting the PPC valve  50 , the EPC valve  60  and the shuttle valve  30  through a pipe line such as a hose, resulting in a smaller installation space of the hydraulic machines in the operation room. As a result, a larger installation space for other than the hydraulic machines in the operation room can be secured. 
   In order to attain the second object, according to a second invention, a hydraulic signal output device provided with manual hydraulic signal output means ( 50 ) that manually output a hydraulic signal from a signal output port ( 15   b ) and externally output it through a pipe line ( 19 ) includes: 
   an electromagnetic valve ( 70 ) in which a hydraulic signal is inputted and an oil passage is opened/closed according to an electrical signal generated by a remote-operation; 
   wherein the signal output port ( 15   b ) and an inlet ( 71   b ) of the electromagnetic valve ( 70 ) are connected and an outlet ( 71   c ) of the electromagnetic valve ( 70 ) is connected to the pipe line ( 19 ); and 
   the electromagnetic valve ( 70 ) is opened to externally output a hydraulic signal outputted from the signal output port ( 15   b ) through the pipe line ( 19 ), and in accordance with a communication release instruction due to the remote-control the electromagnetic valve ( 70 ) is closed to cut off the hydraulic signal outputted from the signal output port ( 15   b ) with the electromagnetic valve ( 70 ). 
   The second invention will be explained with reference to  FIGS. 5 and 6 . 
     FIGS. 5 and 6  show a state where a current does not flow in a solenoid coil  25 . In this state, a pressure oil output port  15   b  of the PPC valve  50  and a pilot pipe line  19  are communicated through the electromagnetic valve ( 70 ), specifically a pressure oil input port  71   b , a notch  72   a  and a pressure oil output port  71   c . Accordingly, pilot pressure oil generated by tilting the operation lever  7  is outputted from the pressure oil output port  15   b  through the pressure oil input port  71   b , the notch  72   a  and the pressure oil output port  71   c  to the pilot pipe line  19 . 
   In accordance with an operation of an operation part  35  outside a vehicle, an energization instruction is radio transmitted. The energization instruction is received at a receiving part  36  inside the vehicle. A controller  37 , based on the energization instruction received at the receiving part  36 , controls a current flowing in the solenoid coil  25 . When the current flows in the solenoid coil  25 , a thrust force is applied on a plunger  26  and the plunger  26  is moved to an arrow mark U direction, that is, toward a spool  72 . As the plunger  26  moves, the spool  72  moves to an arrow mark U direction, that is, toward a pressure-reducing valve  14 . As the spool  72  moves, the communication between the pressure oil input port  71   b  and the notch  72   a  of the spool  72  is cut off. That is, the pressure oil output port  15   b  of the pressure-reducing valve  14  is cut off the pilot pipe line  19  with the electromagnetic valve  70 . 
   According to the second invention, by externally operating the operation part  35 , the operation in the operation room of the vehicle can be limited. 
   Furthermore, in a third invention, a hydraulic signal output device is one that is set forth in the second invention: 
   wherein the manual hydraulic signal output means ( 50 ) and the electromagnetic valve ( 70 ) are integrally formed. 
   According to the third invention, the PPC valve  50  and the electromagnetic valve  70  are integrally formed. Accordingly, there is no need of connecting the PPC valve  50  and the electromagnetic valve  70  through a pipe line such as a hose. As a result, an installation space of the hydraulic machines in the operation room can be made smaller. 
   As a result, a larger space for other than the hydraulic machines in the operation room can be secured. 
   In order to attain the second object, according to a fourth invention, a hydraulic signal output device provided with manual hydraulic signal output means ( 50 ) that manually output a hydraulic signal from a signal output port ( 15   b ) and outputs it though a pipe line ( 19 ) outside thereof includes: 
   electrical hydraulic signal output means ( 80 ) in which a hydraulic signal is inputted, converted into a hydraulic signal in accordance with an electrical signal generated by the remote-operation, and outputted; 
   wherein the signal output port ( 15   b ) and an inlet ( 27   b ) of the electrical hydraulic signal output means ( 80 ) are connected, and an outlet ( 27   d ) of the electrical hydraulic signal output means ( 80 ) is connected to the pipe line ( 19 ); and 
   the electrical hydraulic signal output means ( 80 ) are operated in accordance with a hydraulic signal change instruction due to the remote-operation to modify a hydraulic signal outputted from the signal output port ( 15   b ) and to externally output the modified signal through the pipe line ( 19 ). 
   The fourth invention will be explained with reference to  FIGS. 9 and 10 . 
     FIGS. 9 and 10  show a state where a current does not flow in a solenoid coil  25 . In this state, a pressure oil output port  15   b  of the PPC valve  50  and a pilot pipe line  19  are communicated through the EPC valve ( 80 ), specifically a pressure oil input port  27   b , a notch  28   a , a gap  27   c  and a pressure oil output port  27   d . Accordingly, pilot pressure oil generated by tilting the operation lever  7  is outputted from the pressure oil output port  15   b  through the pressure oil input port  27   b , the notch  28   a  and the pressure oil output port  27   d  to the pilot pipe line  19 . 
   In accordance with an operation of an operation part  35  outside the vehicle, an energization instruction is radio transmitted. The energization instruction is received at a receiving part  36  inside the vehicle. A control part  37 , based on the energization instruction received at the receiving part  36 , controls a current flowing in the solenoid coil  25 . When the current flows in the solenoid coil  25 , a thrust force is applied on a plunger  26  in an arrow mark D direction, that is, toward a spring  38  side. As the plunger  26  moves, a spool  28  moves to an arrow mark D direction, that is, toward the plunger  26  side. At a position where a thrust force toward the spring  38  side acting on the plunger  26  establishes a balance with a spring force of the spring  38  and a pressure of pilot pressure oil acting on the spool  28 , the spool  28  ceases moving. 
   According to the fourth invention, by externally operating the operation part  35 , the operation in the operation room of the vehicle can be limited. 
   Furthermore, in a fifth invention, a hydraulic signal output device is one that is set forth in the fourth invention: 
   wherein the manual hydraulic signal output means ( 50 ) and the electrical hydraulic signal output means ( 80 ) are integrally formed. 
   According to the fifth invention, the PPC valve  50  and the EPC valve  80  are integrally formed. Accordingly, there is no need of connecting the PPC valve  50  and the EPC valve  80  through a pipe line such as a hose. As a result, an installation space of the hydraulic machines in the operation room can be made smaller. 
   Accordingly, in the operation room, a larger space for other than the hydraulic machines can be secured. 
   In order to attain the third object, a hydraulic signal output device according to a sixth invention includes: 
   a manual part ( 50 ) that has a manual spool that is manually operated and outputs a hydraulic signal in accordance with the operation of the manual spool; and 
   a motorized part ( 60 ) that has a motorized shaft that is operated by an electrical signal and outputs a hydraulic signal in accordance with the operation of the motorized shaft; 
   wherein the motorized part ( 60 ) is disposed below the manual part ( 50 ) so that the manual spool and the motorized shaft may be in parallel; and 
   the manual part ( 50 ) and the motorized part ( 60 ) are integrally formed. 
   According to the sixth invention, as shown in  FIG. 15A , the manual part  50  as a PPC valve is attached to a top surface of a top plate  111  of a block  110  so that the internal manual spool may slide in an up and down direction. On the other hand, an electromagnetic solenoid  61  that constitutes the motorized part  60  is attached to a bottom surface of a bottom plate  112  of the block  110  so that the internal motorized shaft (the plunger  26  in  FIG. 1 ) may slide in an up and down direction. Thus, the motorized part  60  is disposed below the manual part  50  so that the manual spool and the motorized shaft may be in parallel, and the manual part  50  and the motorized part  60  are integrally formed. 
   According to the sixth invention, since the manual part  50  and the motorized part ( 60 ) are integrally formed along an up and down direction so that the manual spool and the motorized shaft may be in parallel, a hydraulic signal output device  90  itself can be formed longer in an up and down direction and shorter in a lateral direction. Accordingly, even when the lever stand  80  is small in width, the hydraulic signal output device  90  can be accommodated inside of the lever stand  80 . 
   In a seventh invention, a hydraulic signal output device is one that is set forth in the sixth invention: 
   wherein, to a block ( 110 ) of the hydraulic signal output device, an output port ( 115 ) that externally outputs a hydraulic signal is disposed, and an operation valve that is operated in accordance with a hydraulic signal that is outputted from the output port ( 115 ) is disposed; and 
   of the respective positions of the block ( 110 ), on a side that faces a position where the operation valve is disposed, the output port ( 115 ) is disposed. 
   According to the seventh invention, as shown in  FIGS. 15A and 15C , behind the block  110  of the hydraulic signal output device  90  where the manual part  50  and the motorized part  60  are integrally formed, an operation valve is disposed, and behind a lower portion of the block  110 , that is, on an operation valve side of the various positions of the block  110 , the output port  115  that outputs a hydraulic signal is disposed. The output port  115  and the operation valve are connected with a pipe line  19 . Thus, of various positions of the block  110  of the hydraulic signal output device  90 , on a side that faces a position where the operation valve is disposed, the output port  115  is disposed. 
   According to the seventh invention, since the output port  115  is disposed on a side that faces a position where the operation valve of the block  110  is disposed, the output port  115  is connected at the shortest distance to the operation valve and there is no need of avoiding an obstacle such as the EPC valve  60 , and an easy configuration of the pipe line such as routing of the pipe line  19  results. 
   Furthermore, in an eighth invention, a hydraulic signal output device is one that is set forth in the sixth invention: 
   wherein the motorized part ( 60 ) includes a plurality of electromagnetic valves ( 60 ); and 
   a stand ( 80 ) for accommodating the motorized part ( 60 ) is provided; 
   wherein the plurality of electromagnetic valves ( 60 ) are arranged so that a direction of arrangement of the plurality of electromagnetic valves ( 60 ) may be in parallel with an internal wall surface of the stand ( 80 ). 
   According to the eighth invention, as shown in  FIG. 15C , since four EPC valves  60  (motorized part) are arranged in parallel with the internal wall surface of the lever stand  80 , even when the lever stand  80  is small in a lateral width, the hydraulic signal output device  90  can be accommodated inside the lever stand  80 . 
   Furthermore, in a ninth invention, a hydraulic signal output device is one that is set forth in the sixth invention: 
   wherein the motorized part ( 60 ) includes a plurality of electromagnetic valves ( 60 ); 
   wherein when the electromagnetic valves ( 60 ) are fixed to the block  110  of the hydraulic signal output device by use of a plurality of bolts ( 65   a ,  65   b ), at least one bolt ( 65   b ) is disposed on an axis (L) along a diameter direction of the electromagnetic valve ( 60 ) and a remaining one ( 65   a ) is disposed a little bit off-set from the axis (L). 
   According to the ninth invention, at the time of the EPC valve  60  being fixed to the block  110  of the hydraulic signal output device  90  by use of a plurality of bolts  65   a  and  65   b  (FIG.  15 C), as shown in  FIG. 16 , at least one bolt  65   b  is disposed on an axis L along a diameter direction of the EPC valve  60  and a remaining one  65   a  is disposed a little bit off-set from the axis L. Accordingly, a bolt  113  used to attach to the block  110  and the bolt  65   a  are inhibited from interfering each other. 
   Furthermore, in order to attain the third object, a hydraulic signal output device according to a tenth invention includes: 
   a manual part ( 50 ) that has a manual spool that is manually operated and outputs a hydraulic signal in accordance with the operation of the manual spool; and 
   a motorized part ( 60 ) that has a motorized shaft that is operated by an electrical signal and outputs a hydraulic signal in accordance with the operation of the motorized shaft; 
   wherein the motorized part ( 60 ) is partially or entirely disposed at a height substantially equal to the manual part ( 50 ) so that the manual spool and the motorized shaft may be in parallel; and 
   the manual part ( 50 ) and the motorized part ( 60 ) are integrally formed. 
   According to the tenth invention, as shown in  FIGS. 18A and 18B , the manual part  50  as a PPC valve is attached to a top surface of a top plate  111  of the block  110  so that the manual spool in the manual part may slide in an up and down direction. On the other hand, an electromagnetic solenoid  61  that constitutes the motorized part  60  as the EPC valve is attached to a top surface of a top plate  111  of the block  110  so that the motorized shaft in the electromagnetic solenoid (the plunger  26  in  FIG. 1 ) may slide in an up and down direction. Thus, the motorized part  60  (electromagnetic solenoid  61 ) is partially disposed at a height substantially same as the manual part  50  so that the manual spool and the motorized shaft may be in parallel, and the manual part  50  and the motorized part  60  are integrally formed. An entirety of the motorized part  60  (the electromagnetic solenoid  61  and the pressure-reducing valve  27  in  FIG. 1 ) may be disposed at a height substantially same as the manual part  50 . 
   According to the tenth invention, since the motorized part  60  is partially or entirely disposed at a height substantially same as the manual part  50  so that the manual spool and the motorized spool may be in parallel and the manual part  50  and the motorized part  60  are integrally formed, a hydraulic signal output device  92  itself can be formed shorter in an up and down direction. Accordingly, even when the lever stand  80  is lower in height, the hydraulic signal output device  92  can be accommodated inside of the lever stand  80 . 
   In order to attain the third object, a hydraulic signal output device according to an eleventh invention includes: 
   a manual part ( 50 ) that has a manual spool that is operated manually and outputs a hydraulic signal in accordance with the operation of the manual spool; and 
   a motorized part ( 60 ) that has a motorized shaft that is operated by an electrical signal and outputs a hydraulic signal in accordance with the operation of the motorized shaft; 
   wherein the manual part ( 50 ) and the motorized part ( 60 ) are integrally formed so that the motorized shaft may be vertical with respect to the manual spool. 
   According to the eleventh invention, as shown in  FIGS. 19A and 19B , the manual part  50  as a PPC valve is attached to a top surface of a top plate  111  of a block  110  so that the manual spool in the manual part may slide in an up and down direction. On the other hand, an electromagnetic solenoid  61  that constitutes the motorized part  60  as an EPC valve is attached to side surfaces of side plates  116  and  117  of the block  110  so that the motorized shaft in the electromagnetic valve (the plunger  26  in  FIG. 1 ) may slide in a lateral direction. Thus, the manual part  50  and the motorized part  60  are integrally formed so that the manual shaft may be vertical with respect to the manual spool. 
   According to the eleventh invention, since the manual part  50  and the motorized part ( 60 ) are integrally formed so that the motorized shaft may be vertical with respect to the manual spool, a hydraulic signal output device  93  can be expanded in width and shortened in an up and down direction. Accordingly, within the lever stand  80  that is low in height and has a room in width, the hydraulic signal output device  93  can be accommodated. 
   A hydraulic signal output device according to a twelfth invention is one that is set forth in the tenth invention: 
   wherein the motorized part ( 60 ) has an electromagnetic solenoid ( 61 ), and the motorized shaft is a plunger ( 26 ) of the electromagnetic solenoid ( 61 ); 
   wherein the electromagnetic solenoid ( 61 ) is disposed at a height substantially same as the manual part ( 50 ) so that the manual spool and the motorized shaft may be in parallel with each other. 
   According to the twelfth invention, as shown in  FIG. 18A , the electromagnetic solenoid  61  that is part of the motorized part  60  is disposed at a height substantially same as the manual part  50 . 
   A hydraulic signal output device according to a thirteenth invention is one that is set forth in the eleventh invention: 
   wherein the motorized part ( 60 ) has an electromagnetic solenoid ( 61 ), and the motorized shaft is a plunger ( 26 ) of the electromagnetic solenoid ( 61 ); 
   wherein the electromagnetic solenoid ( 61 ) is disposed sideward with respect to the manual part ( 50 ) so that the motorized shaft may be vertical with respect to the manual spool. 
   According to the thirteenth invention, as shown in  FIG. 19A , the electromagnetic solenoid  61  that is part of the motorized part  60  is disposed sideward with respect to the manual part  50 . 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a sectional view showing a first embodiment of the present invention. 
       FIG. 2  is a diagram showing an oil pressure circuit of the first embodiment. 
       FIG. 3  is a diagram showing a pressure-reducing valve in a simplified way. 
       FIG. 4  is a diagram showing a pressure-reducing valve in a simplified way. 
       FIG. 5  is a sectional view showing a second embodiment of the present invention. 
       FIG. 6  is a diagram showing an oil pressure circuit of the second embodiment. 
       FIG. 7  is a sectional view showing a third embodiment of the present invention. 
       FIG. 8  is a diagram showing an oil pressure circuit of the third embodiment. 
       FIG. 9  is a sectional view showing a fourth embodiment of the present invention. 
       FIG. 10  is a diagram showing an oil pressure circuit of the fourth embodiment. 
       FIGS. 11A and 11B  are diagrams for explaining a bi-axial pilot valve. 
       FIG. 12  is a sectional view showing a PPC valve. 
       FIG. 13  is a sectional view showing an EPC valve. 
       FIG. 14  is an oil pressure circuit showing the PPC valve, the EPC valve and a shuttle valve. 
       FIGS. 15A through 15C  are a side view, a plan view and a bottom view of a hydraulic signal output device  90 , respectively. 
       FIG. 16  is a diagram showing a positional relationship between the EPC valve  60  and bolts  65   a ,  65   b.    
       FIGS. 17A through 17C  are a side view, a plan view and a bottom view of a hydraulic signal output device  91 , respectively. 
       FIGS. 18A through 18C  are a side view, a plan view and a bottom view of a hydraulic signal output device  92 , respectively. 
       FIGS. 19A through 19C  are a side view, a plan view and a bottom view of a hydraulic signal output device  93 , respectively. 
       FIG. 20  is a diagram showing an operator&#39;s seat  100  disposed in an operation room. 
       FIGS. 21A through 21C  are a side view, a plan view and a bottom view of a hydraulic signal output device  50 , respectively. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   In the following, embodiments of a hydraulic signal output device according to the present invention will be explained with reference to the drawings. 
     FIG. 1  is a sectional view showing a first embodiment of the present invention.  FIG. 2  is a diagram showing an oil pressure circuit of the first embodiment. Furthermore,  FIGS. 11A and 11B  are diagrams showing movement of an operation lever in a two axis pilot valve.  FIG. 1  is a drawing of an A—A section of  FIG. 11A  seen from left. The explanation will be given with reference to all these drawings. 
   A configuration of a hydraulic signal output device  1  will be explained. 
   The hydraulic signal output device  1  shown in  FIG. 1  largely includes a PPC valve  50 , an EPC valve  60  and a shuttle valve  30 , the oil pressure machines  30 ,  50  and  60  being integrated into one body. The PPC valve  50  and the EPC valve  60  are connected with the shuttle valve  30  interposed therebetween. 
   In the following, the PPC valve  50  will be explained. The PPC valve  50  is the same as the hydraulic signal output device  50  shown in FIG.  12 . 
   The PPC valve  50  largely includes a body  51  and an operation lever  7  disposed in a tilting-free manner with respect to the body  51 . 
   The operation lever  7  is attached through a free joint  8  and a disc plate  9  to the body  51  so as to be tilted freely in a left and right direction (F, B direction) in FIG.  1  and in a direction perpendicular to a paper surface (L, R direction). 
   The disc plate  9  is attached to the operation lever  7  so that tip ends (upper end) of pistons  3 ,  4 ,  5  and  6  may come into contact with a bottom surface of the disc plate  9 . 
   As shown in  FIGS. 11A and 11B , the four pistons  3 ,  4 ,  5  and  6  are disposed so that the tip ends of pistons (upper end) may project from an attachment plate  10 . The pistons  3 ,  4 ,  5  and  6  are disposed so that these may be located at four corners of a square when seen from a top surface of the attachment plate  10 . When the operation lever  7  is tilted toward an F direction, the piston  6  is pushed down by the disc plate  9  and pilot pressure oil corresponding to a stroke of the piston  6  is output. Furthermore, when the operation lever  7  is tilted toward a B direction, the piston  4  is pushed down by the disc plate  9  and pilot pressure oil corresponding to a stroke of the piston  4  is output. Still furthermore, when the operation lever  7  is tilted toward an R direction, the piston  3  is pushed down by the disc plate  9  and pilot pressure oil corresponding to a stroke of the piston  3  is output. Furthermore, when the operation lever  7  is tilted toward an L direction, the piston  5  is pushed down by the disc plate  9  and pilot pressure oil corresponding to a stroke of the piston  5  is output. 
   The pistons  3 ,  4 ,  5  and  6  move in accordance with a tilting direction and an amount of tilting of the operation lever  7 . In the following, the piston  6  will be explained as a typical example. However, the situations are the same also with respect to the pistons  3 ,  4  and  5 . 
   As shown in  FIG. 1 , a first spring  12  is disposed between the piston  6  and a spring washer  51 a of the body  51 . When the operation lever  7  is tilted toward the F direction, the piston  6 , while being subjected to a spring force of the first spring  12 , is pushed down toward an arrow mark D direction. The operator can feel sense of operation through the spring force of the first spring  12  when the operation lever  7  is tilted. 
   In the body  51 , for each of the pistons, a pressure-reducing valve  14  for generating pilot pressure oil having a pressure corresponding to a thrust force of the piston is disposed. 
     FIG. 3  is a drawing showing a pressure-reducing valve of the PPC valve in a simplified manner. 
   In the pressure-reducing valve  14 , a spool slide hole  14   a  is formed. The spool  15  slides in the spool slide hole  14   a  in an arrow mark U direction or an arrow mark D direction. 
   In the spool slide hole  14   a , a pressure oil input port  14   b  for inputting pressure oil discharged from a not shown hydraulic pump is formed. 
   One end of the spool  15  is connected to the piston  6  through a second spring  13 . As a result, owing to the thrust force of the piston  6 , the spool  15  slides inside of the spool slide hole  14   a . In a slide surface of the spool  15 , a notch  15   a  is formed, and at the other end of the spool  15  a pressure oil output port  15   b  is formed. Inside of the spool  15 , an internal pipe line  15   c  that communicates the notch  15   a  and the pressure oil output port  15   b  is formed. The pressure oil output port  15   b  is communicated through a pressure oil input port  30   a  of the shuttle valve  30  with a pilot pipe line  19 . In the spool  15 , pressure-receiving parts  15   d  and  15   e  are formed and receive pressure of the outputted pilot pressure oil. 
   The spool  15  receives the pressure of the pilot pressure oil at the pressure-receiving parts  15   d  and  15   e . The spool  15 , upon receiving the pressure due to the pilot pressure oil, moves in an arrow mark U direction, that is, toward the piston  6 . Thereby, an area of an opening where the notch  15   a  and the pressure oil input port  14   b  overlap is restricted. As a result, the pressure oil inputted from the hydraulic pump into the pressure-reducing valve  14  is depressurized and outputted into the pilot pipe line  19 . The spool  15  stops moving at a position where the pressure of the pilot pressure oil outputted into the pilot pipe line  19  and the spring force of the second spring  13  balance. 
   In the case of a displacement of the spool  15  in an arrow mark D direction being a predetermined amount or less, that is, an amount of tilting of the operation lever  7  being a predetermined amount or less, the notch  15   a  is not communicated with the pressure oil input port  14   b  but communicated with a not shown tank. In the case of a displacement of the spool  15  in an arrow mark D direction exceeding a predetermined amount, that is, an amount of tilting of the operation lever  7  exceeding a predetermined amount, the notch  15   a  is communicated with the pressure oil input port  14   b.    
   Subsequently, the EPC valve  60  will be explained. The EPC valve  60  is the same as the hydraulic signal output device  60  shown in FIG.  13 . 
   The EPC valve  60  includes a solenoid coil  25 , a plunger  26  that moves upon receiving a thrust force that is generated when the solenoid coil  25  is energized, and a pressure-reducing valve  27  that generates pilot pressure oil having a pressure corresponding to a thrust force of the plunger  26 . 
   The plunger  26  is disposed in a center shaft portion of the cylindrical-solenoid coil  25 . One end of the plunger  26  is connected with one end of the spool  28  of the pressure-reducing valve  27 . 
     FIG. 4  is a drawing showing the pressure-reducing valve of the EPC valve in a simplified manner. 
   In the pressure-reducing valve  27 , a spool slide hole  27   a  is formed. The spool  28  slides in the spool slide hole  27   a  in an arrow mark U direction or an arrow mark D direction. 
   In the spool slide hole  27   a , a pressure oil input port  27   b  for inputting pressure oil discharged from a not shown hydraulic pump and a gap  27   c  that is allowed communicating with a pressure oil input port  27   b  owing to the displacement of the spool  28  are formed. The gap  27   c  is communicated through the pressure oil output port  27   d  and a pressure oil input port  30   b  of the shuttle valve  30  with the pilot pipe line  19 . 
   One end of the spool  28  is connected to the plunger  26 . As a result, as the plunger  26  displaces, the spool  28  slides inside of the spool slide hole  27   a . In a slide surface of the spool  28 , a notch  28   a  is formed. Furthermore, in a slide surface of the spool  28 , an annular part  28   b  that, when the pressure oil input port  27   b  and the gap  27   c  are communicated, is located inside of the gap  27   c  and receives the pressure of the outputted pilot pressure oil is formed. The pressure of the pilot pressure oil acts on the annular part  28   b  of the spool  28 . The spool  28 , upon receiving the pressure due to the pilot pressure oil, moves in an arrow mark D direction, that is, toward the plunger  26 . The plunger  26  moves, upon receiving the thrust force due to the spool  28 , toward an arrow mark D direction. Thereby, an area of an opening where the notch  28   a  and the gap  27   c  overlap is restricted. As a result, the pressure oil inputted from the hydraulic pump into the pressure-reducing valve  27  is depressurized and outputted into the pilot pipe line  19 . The spool  28  stops moving at a position where the pressure of the pilot pressure oil and the thrust force of the plunger  26  balance. 
   In the case of a displacement of the spool  28  in an arrow mark U direction being a predetermined amount or less, that is, an electric current flowing in the solenoid coil  25  being a predetermined amount or less, the pressure oil input port  27   b  is not communicated with the gap  27   c  but communicated with a not shown tank. In the case of a displacement of the spool  28  in an arrow mark U direction exceeding a predetermined amount, that is, an electric current flowing in the solenoid coil  25  exceeding a predetermined amount, the pressure oil input port  27   b  is communicated through the notch  28   a  with the gap  27   c.    
   Next, the shuttle valve  30  will be explained. 
   In the shuttle valve  30 , pressure oil input ports  30   a  and  30   b  and a pressure oil output port  30   c  are formed. A ball  31  is disposed with the pressure oil input port  30   a  and the pressure oil input port  30   b  freely closable. The pressure oil input port  30   a  is communicated with the pressure oil output port  15   b  of the pressure-reducing valve  14 . The pressure oil input port  30   b  is communicated with the pressure oil output port  27   d  of the pressure-reducing valve  27 . The pressure oil output port  30   c  is communicated with the pilot pipe line  19 . When the ball  31  closes a pressure oil input portion  30   b  side, the pressure oil input portion  30   a  is communicated with the pressure oil output portion  30   c . When the ball  31  closes a pressure oil input port  30   a  side, the pressure oil input port  30   b  is communicated with the pressure oil output port  30   c.    
   The hydraulic signal output device  1 , other than being operated with the operation lever  7 , can be operated also with an operation part  35  shown in FIG.  2 . The operation part  35  shown in  FIG. 2  is a wireless device disposed outside the vehicle, and according to the operation at the operation part  35  an energizing instruction is radio-transmitted. With the energizing instruction, a magnitude of an electric current that is allowed flowing in the solenoid coil  25  can be instructed. A receiving part  36  receives the energizing instruction transmitted from the operation part  35 . A control part  37 , based on the energizing instruction received at the receiving part  36 , controls the electric current that flows in the solenoid coil  25 . 
   Subsequently, operations of the hydraulic signal output device  1  will be explained. 
   First, a case where an operator tilts the operation lever  7  in operating will be explained with reference to  FIGS. 1 ,  2  and  3 . 
     FIGS. 1 and 2  show a state where the operation lever  7  is in a neutral position. In this state, it is assumed that the operation lever  7  is tilted toward the piston  6  (F direction in FIG.  1 ). At this, the piston  6  at the left side in  FIG. 1  receives the thrust force through the disc plate  9  and moves in an arrow mark D direction, that is, toward the spool  15 . The spool  15  receives the thrust force due to the piston  6  through the second spring  13  and moves in an arrow mark D direction, that is, toward the shuttle valve  30  side. 
   The spool  15  receives the pressure of the pilot pressure oil at the pressure-receiving portions  15   d  and  15   e . The spool  15 , upon receiving the pressure due to the pilot pressure oil, moves in an arrow mark U direction, that is, toward the piston  6  side. Thereby, an area of an opening where the notch  15   a  and the pressure oil input port  14   b  overlap is restricted. As a result, the pressure oil that is inputted from the hydraulic pump into the pressure-reducing valve  14  is depressurized and outputted into the pilot pipe line  19 . When the pressure of the pilot pressure oil outputted into the pilot pipe line  19  and the spring force of the second spring  13  establish a balance, the spool  15  stops moving. 
   When a displacement in an arrow mark D direction of the spool  15  exceeds a predetermined amount, the notch portion  15   a  is communicated with the pressure oil input port  14   b . Accordingly, the pressure oil that is discharged from a not shown hydraulic pump is outputted through the pressure oil input port  14   b , the notch portion  15   a  and an internal pipe line  15   c  from the pressure oil output port  15   b  into the pressure oil input port  30   a  of the shuttle valve  30 . The pressure of the outputted pressure oil establishes a balance with the spring force of the second spring  13 . 
   The pressure oil inputted into the shuttle valve  30  moves the ball  31  in an arrow D direction, that is, toward the pressure oil input port  30   b  and closes the pressure oil input port  30   b  and opens the pressure oil input port  30   a . Thereby, the pressure oil output port  15   b  of the pressure-reducing valve  14  is communicated with the pilot pipe line  19 . The pressure oil output port  27   d  of the pressure-reducing valve  27  is cut off the pilot pipe line  19 . 
   Thus, the pilot pressure oil Pp having a magnitude in accordance with a tilting amount of the operation lever  7  is outputted into the pilot pipe line  19 . Similarly, when in accordance with the tilting of the operation lever  7 , each of the pistons  3 ,  4  and  5  moves, the pilot pressure oil Pp is outputted into each of the pilot pipe lines  16 ,  17  and  18 . 
   Subsequently, a case where a person other than an operator who operates the hydraulic signal output device  1  in the vehicle operates the operation part  35  will be explained with reference to  FIGS. 1 ,  2  and  3 . 
     FIGS. 1 and 2  show a state where an electric current does not flow in the solenoid coil  25 . In this state, it is assumed that the operation part  35  is operated and the energizing instruction is radio-transmitted. The energizing instruction is received at the receiving part  36  and sent to the control part  37 . The control part  37  allows a current having a magnitude shown in the content of the energizing instruction to flow. Thereby, the thrust force corresponding to the magnitude of the current is generated, and thereby the plunger  26  is moved in an arrow mark U direction, that is, toward the spool  28  side. The spool  28 , upon receiving the thrust force due to the plunger  26 , moves in an arrow mark U direction, that is, toward the shuttle valve  30  side. 
   The pressure of the pilot pressure oil acts on the annular part  28   b  of the spool  28 . The spool  28 , upon receiving the pressure due to the pilot pressure oil, moves in an arrow mark D direction, that is, toward the plunger  26 . The plunger  26 , upon receiving the thrust force due to the spool  28 , moves toward an arrow mark D direction. Thereby, an area of an opening where the notch  28   a  and the gap  27   c  overlap is restricted. As a result, the pressure oil inputted from the hydraulic pump into the pressure-reducing valve  27  is depressurized and outputted into the pilot pipe line  19 . The spool  28  stops moving at a position where the pressure of the pilot pressure oil establishes a balance with the thrust force of the plunger  26 . 
   When the displacement of the spool  28  in an arrow mark U direction exceeds a predetermined amount, the pressure oil input port  27   b  and the gap  27   c  are communicated through the notch  28   a . Accordingly, the pressure oil that is discharged from a not shown hydraulic pump is outputted through the pressure oil input port  27   b , the notch  28   a  and the gap  27   c  from the pressure oil output port  27   d  into the pressure oil input port  30   b  of the shuttle valve  30 . The pressure of the outputted pressure oil establishes a balance with the thrust force of the plunger  26 . 
   The pressure oil inputted into the shuttle valve  30  moves the ball  31  in an arrow U direction, that is, toward the pressure oil input port  30   a  side and closes the pressure oil input port  30   a  and opens the pressure oil input port  30   b . Thereby, the pressure oil output port  27   d  of the pressure-reducing valve  27  is communicated with the pilot pipe line  19 . The pressure oil output port  15   b  of the pressure-reducing valve  14  is cut off the pilot pipe line  19 . 
   Thus, the pilot pressure oil Pp having a magnitude in accordance with the energizing instruction radio-transmitted from the operation part  35  is outputted into the pilot pipe line  19 . 
   In the first embodiment, various hydraulic machines such as the PPC valve  50 , the EPC valve  60  and the shuttle valve  30  are integrally formed. Accordingly, since the installation space of the hydraulic machines can be made smaller, a space for other than the hydraulic machines can be made larger. 
   In the following, a second embodiment will be explained. 
     FIG. 5  is a sectional view showing a second embodiment of the present invention.  FIG. 6  is a drawing showing an oil pressure circuit of the second embodiment.  FIGS. 11A and 11B  show movement of an operation lever shown in FIG.  5 .  FIG. 5  is a drawing of an A—A section of  FIG. 11A  seen from left. These drawings will be together referenced to explain the second embodiment. 
   A hydraulic signal output device  32  shown in  FIG. 5  largely includes a PPC valve  50  and an electromagnetic valve  70 . 
   In the second embodiment, the electromagnetic valve  70  cuts off pilot pressure oil outputted from the PPC valve  50 . When an operation part  35  is operated, the electromagnetic valve  70  is actuated. 
   The PPC valve  50  is the same as that explained in the first embodiment. Accordingly, an explanation thereof will be omitted. 
   The electromagnetic valves  70  are disposed corresponding to each of pistons  3 ,  4 ,  5  and  6  of the PPC valve  50 . Each of the electromagnetic valves  70  is provided with a solenoid coil  25 , a plunger  26  that moves when the thrust force that is generated in accordance with a current flowing in the solenoid coil  25  is received, and a switching valve  71  that allows a pressure oil output port  15   b  of a pressure-reducing valve  14  communicating with or cutting off a pilot pipe line  19  owing to the thrust force of the plunger  26 . 
   The plunger  26  is disposed in a center shaft portion of the cylindrical solenoid coil  25 . One end of the plunger  26  is connected to one end of a spool  72  of the switching valve  71 . 
   In the switching valve  71 , a spool slide hole  71   a  is formed. The spool  72  slides in the spool slide hole  71   a  in an arrow U direction or an arrow D direction. 
   In the spool slide hole  71   a , a pressure oil input port  71   b  that inputs the pressure oil discharged from the PPC valve  50 , and a pressure oil output port  71   c  that is communicated with the pressure oil input port  71   b  owing to the displacement of the spool  72  are formed. The pressure oil input port  71   b  is communicated with the pressure oil output port  15   b  of the pressure-reducing valve  14 , and the pressure oil output port  71   c  is communicated with the pilot pipe line  19 . 
   One end of the spool  72  is connected with the plunger  26 . Accordingly, as the plunger  26  moves, the spool  72  slides inside of the spool slide hole  71   a . In a sliding surface of the spool  72 , a notch  72   a  is formed. The notch  72   a  allows the pressure oil input port  71   b  to communicate with the pressure oil output port  71   c.    
   In the case of a displacement in an arrow mark U direction of the spool  72  being a predetermined amount or less, that is, a current flowing in the solenoid coil  25  being a predetermined amount or less, the pressure oil input port  71   b  is communicated through the notch  72   a  with the pressure oil output port  71   c . In the case of a displacement in an arrow mark U direction of the spool  72  exceeding a predetermined amount, that is, a current flowing in the solenoid coil  25  exceeding a predetermined amount, the pressure oil input port  71   b  is cut off the pressure oil output port  71   c.    
   Subsequently, the operations of the hydraulic signal output device  32  will be explained. 
     FIGS. 5 and 6  show a state where the operation lever  7  is in a neutral position. Furthermore, the drawings show a state where a current does not flow in the solenoid coil  25 . In this state, it is assumed that the operation lever  7  is tilted toward the piston  6  (F direction in FIG.  5 ). Thereby, the pressure oil outputted from the pressure oil output port  15   b  of the pressure-reducing valve  14  is outputted through the pressure oil input port  71   b , the notch  72   a  and the pressure oil output port  71   c  to the pilot pipe line  19 . 
   In this state, it is assumed that the operation part  35  is operated and the energizing instruction is radio-transmitted. In the energizing instruction, a current sufficient to displace the plunger  26  flows in the solenoid coil  25 . The energizing instruction is received at the receiving part  36  and sent to the control part  37 . The control part  37  allows a current having a magnitude shown in the content of the energizing instruction to flow in the solenoid coil  25 . Thereby, the thrust force corresponding to the magnitude of the current is generated, and thereby the plunger  26  is moved in an arrow mark U direction, that is, toward the spool  72 . The spool  72 , upon receiving the thrust force due to the plunger  26 , moves in an arrow mark U direction, that is, toward the PPC valve  50  side. 
   When a displacement of the spool  72  in an arrow mark U direction exceeds a predetermined amount, the pressure oil input port  71   b  is cut off the pressure oil output port  71   c  by means of the spool  71   c . That is, the pressure oil output port  15   b  of the pressure-reducing valve  14  is cut off the pilot pipe line  19  by means of the electromagnetic valve  70 . 
   Thus, in the hydraulic signal output device  32 , when the current is not flowing in the solenoid coil  25 , the pilot pressure oil is outputted from the PPC valve  50  to the pilot pipe line  19 . However, when the current is flowing in the solenoid coil  25 , the pilot pressure oil outputted from the PPC valve  50  is cut off the pilot pipe line  19  by means of the electromagnetic valve  70  and is not outputted thereto. When the operation part  35  is operated and allows the current to flow in the solenoid coil  25 , the pressure oil supplied to a not shown hydraulic motor is stopped, resulting in stopping the vehicle. 
   In the second embodiment, by allowing the current to flow in the solenoid coil  25 , the pressure oil input port  71   b  of the switching valve  71  is cut off the pressure oil output port  71   c  thereof. However, by not allowing the current to flow in the solenoid coil  25 , the pressure oil input port  71   b  of the switching valve  71  may not cut off the pressure oil output port  71   c  thereof. 
   Next, a third embodiment will be explained. 
     FIG. 7  is a sectional view showing a third embodiment of the present invention.  FIG. 8  is a drawing showing an oil pressure circuit of the third embodiment. Furthermore,  FIGS. 11A and 11B  show movement of an operation lever shown in FIG.  7 .  FIG. 7  is a drawing of an A—A section seen from left of FIG.  11 A. These drawings will be together referenced to explain the third embodiment. 
   A hydraulic signal output device  40  shown in  FIG. 7 , largely includes a PPC valve  50  and an EPC valve  60 . 
   In the third embodiment, the pilot pressure oil outputted from the PPC valve  50  is depressurized by use of the EPC valve  60 . When the operation part  35  is operated, the EPC valve  60  is actuated. 
   The PPC valve  50  and the EPC valve  60  are the same as those explained in the first embodiment. Accordingly, an explanation thereof will be omitted. 
   The pressure oil output port  15   b  of the pressure-reducing valve  14  in the PPC valve  50  is communicated with the pressure oil input port  27   b  of the pressure-reducing valve  27  in the EPC valve  60 . Furthermore, the pressure oil output port  27   d  of the pressure-reducing valve  27  is communicated with the pilot pipe line  19 . The PPC valve  50  and the EPC valve  60  are integrally formed. 
   In the following, operations of the hydraulic signal output device  40  will be explained. 
     FIGS. 7 and 8  show a state where the operation lever  7  is in a neutral position and a state where a current is not flowing in the solenoid coil  25 . 
   When a not shown engine is started operating, a predetermined amount of an electric current flows in the solenoid coil  25 , and the spool  28  is moved toward the PPC valve  50  side, that is, in an arrow mark U direction. At that time, the pressure oil input port  15   b  is communicated through the pressure oil input port  27   b , the notch  28   a , the gap  27   c  and the pressure oil output port  27   d  with the pilot pipe line  19 . When there is no external energizing instruction while the engine of the vehicle is operating, a predetermined amount of current keeps on flowing in the solenoid coil  25 . In a state where the predetermined amount of the current keeps on flowing in the solenoid coil  25 , it is assumed that the operation lever  7  is tilted toward the piston  6  (F direction in FIG.  7 ). Thereby, the pressure oil that is outputted from the pressure oil output port  15   b  is outputted through the pressure oil input port  27   b , the notch  28   a , the gap  27   c  and the pressure oil output port  27   d  to the pilot pipe line  19 . 
   In this state, it is assumed that the operation part  35  is operated and an energizing instruction is radio-transmitted. The energizing instruction is received at the receiving part  36  and is sent to the control part  37 . The control part  37  allows a current having a magnitude shown in the content of the energizing instruction to flow. When, in accordance with the energizing instruction, the current flowing in the solenoid coil  25  is made smaller than the predetermined amount, the generated thrust force becomes smaller. The spool  28  is subjected to the pressure of the pilot pressure oil acting on the annular part  28   b  and is moved in an arrow D direction, that is, toward the plunger  26  side. Thereby, an area of the opening through which the notch  28   a  and the gap  27   c  overlap is restricted. As a result, the pressure oil that is inputted from the PPC valve  50  to the pressure-reducing valve  27  is depressurized and outputted to the pilot pipe line  19 . The spool  28  ceases moving at a position where the pressure of the pilot pressure oil and the thrust force of the plunger  26  establish a balance. 
   By performing as mentioned above, in the hydraulic signal output device  40 , as the current flowing in the solenoid coil  25  becomes smaller, the pilot pressure oil having a smaller pressure can be outputted into the pilot pipe line  19 . Accordingly, when the operation part  35  is operated and the current flowing in the solenoid coil  25  is made gradually smaller, the pilot pressure oil supplied to a not shown operation valve can be gradually depressurized. Thereby, since the pressure oil supplied to the hydraulic motor decreases gradually, a speed of a running vehicle can be gradually lowered, resulting in standing still. 
   In the following, a fourth embodiment will be explained. 
     FIG. 9  is a sectional view showing a fourth embodiment of the present invention.  FIG. 10  is a drawing showing an oil pressure circuit of the fourth embodiment.  FIGS. 11A and 11B  show movement of an operation lever shown in FIG.  9 .  FIG. 9  is a drawing of an A—A section of  FIG. 11A  seen from left. These drawings will be together referenced to explain the fourth embodiment. 
   A hydraulic signal output device  45  shown in  FIG. 9  largely includes a PPC valve  50  and an EPC valve  80 . 
   In the fourth embodiment, pilot pressure oil outputted from the PPC valve  50  is depressurized with the EPC valve  80 . The EPC valve  80  is operated when the operation part  35  is operated. While in the third embodiment, when the current flowing in the solenoid coil  25  of the EPC valve  60  is made smaller, the pressure of the pilot pressure oil outputted from the pilot pipe line  19  becomes smaller, in the fourth embodiment, when the current flowing in the solenoid coil  25  of the EPC valve  80  is made larger, the pressure of the pressure oil outputted from the pilot pipe line  19  becomes smaller. 
   The PPC valve  50  is the same as that explained in the first embodiment. Accordingly, an explanation thereof will be omitted. Furthermore, the EPC valve  80  will be explained only of portions different from the EPC valve  60  that is explained in the first embodiment. 
   A pressure oil output port  15   b  of the pressure-reducing valve  14  in the PPC valve  50  is communicated with a pressure oil input port  27   b  of the pressure-reducing valve  27  in the EPC valve  80 . Furthermore, a pressure oil output port  27   d  of the pressure-reducing valve  27  in the EPC valve  80  is communicated with the pilot pipe line  19 . The PPC valve  50  and the EPC valve  80  are integrally formed. 
   One end of the plunger  26  of the EPC valve  80  is connected with the spool  28  of the pressure-reducing valve  27 . The other end of the plunger  26  is connected with one end of a spring  38 . The other end of the spring  38  is connected with a spring washer  38   a . When a current flows in the solenoid coil  25 , the thrust force is applied on the plunger  26  toward the spring  38  side. The EPC valve  80  is called a proportional EPC valve, and the thrust force proportional to a magnitude of the current flowing in the solenoid coil  25  acts in an arrow mark D direction. 
   In the case of a displacement of the spool  28  in an arrow mark D direction being a predetermined amount or less, that is, the current flowing in the solenoid coil  25  being a predetermined amount or less, the pressure oil input port  27   b  is communicated through the notch  28   a  with the gap  27   c . In the case of a displacement of the spool  28  in an arrow mark D direction exceeding a predetermined amount, that is, the current flowing in the solenoid coil  25  exceeding a predetermined amount, the pressure oil input port  27   b  is cut off the gap  27   c.    
   Subsequently, operations of the hydraulic signal output device  45  will be explained. 
     FIGS. 9 and 10  show a state where the operation lever  7  is in a neutral position. Furthermore, the drawings show a state where a current does not flow in the solenoid coil  25 . In this state, it is assumed that the operation lever  7  is tilted toward the piston  6  (F direction in FIG.  9 ). Thereby, the pressure oil outputted from the pressure oil output port  15   b  is outputted through the pressure oil input port  27   b , the notch  28   a , the gap  27   c  and the pressure oil output port  27   d  to the pilot pipe line  19 . 
   It is assumed that, in this state, the operation part  35  is operated and an energizing instruction is radio-transmitted. The energizing instruction is received at the receiving part  36  and sent to the control part  37 . The control part  37  allows a current having a magnitude shown in the content of the energizing instruction to flow in the solenoid coil  25 . When the current flowing in the solenoid coil  25  is made larger in accordance with the energizing instruction, a larger thrust force is generated. Thereby, owing to the generated thrust force, the plunger  26  is moved in an arrow mark D direction, that is, toward the spring  38  side. The spool  28 , upon receiving the thrust force due to the plunger  26 , moves in an arrow mark D direction, that is, toward the EPC valve  80  side. Thereby, the spring  38  is forced to contract. 
   The pressure oil inputted from the PPC valve  50  into the pressure-reducing valve  27  is depressurized and outputted to the pilot pipe line  19 . The spool  28  stops moving at a position where the pressure of the pilot pressure oil acting on the spool  28  and the thrust force acting on the plunger  26  establish a balance with the spring force of the spring  38 . 
   As mentioned above, in the hydraulic signal output device  45 , as the current flowing in the solenoid coil  25  becomes larger, the pilot pressure oil having a smaller pressure can be outputted to the pilot pipe line  19 . Accordingly, when the operation part  35  is operated and the current flowing in the solenoid coil  25  is made gradually larger, the pilot pressure oil supplied to a not shown operation valve can be gradually depressurized. Thereupon, since the pressure oil supplied to the hydraulic motor gradually decreases, a speed of a running vehicle can be gradually lowered, resulting in stopping the vehicle. 
   The operation part  35  sends a signal to the receiving part  36  by radio-transmission. However, the signal may be transmitted to the receiving part  36  by wire-communication. 
   In the following, arrangement modes of the above mentioned PPC valve  50  and the EPC valve  60  will be explained. 
     FIG. 20  shows an operator&#39;s seat  100  disposed in an operation room. At the sideward of the operator&#39;s seat  100 , a lever stand  80  is arranged. The lever stand  80  is equipped with a hydraulic signal output device that is constituted of the PPC valve  50  and the EPC valve  60 . To the hydraulic signal output device, an operation lever  7  is attached and disposed so as to project upward from the lever stand  80 . 
   Since the operation lever  7  directly operates the PPC valve  50 , there is necessity to dispose the PPC valve  50  above the lever stand  80 . On the other hand, since the EPC valve  60  is remote-controlled, the EPC valve  60  can be arbitrarily disposed inside of the lever stand  80 . Accordingly, in accordance with a shape of the lever stand  80 , the EPC valve  60  can be placed at the most appropriate place. In the following, various implementation modes of the placement with respect to the EPC valve  60  will be explained. 
   The following explanation of an internal configuration of the hydraulic signal output device assumes the configuration of  FIG. 1  (the first embodiment). However, the explanation can be similarly applied even to the configurations assuming  FIG. 5  (the second embodiment),  FIG. 7  (the third embodiment) and  FIG. 9  (the fourth embodiment). 
     FIGS. 15A through 15C  are drawings showing a fifth embodiment of the present invention, and show a side view, a plan view and a bottom view, respectively, of a hydraulic signal output device  90 .  FIG. 15A  is a drawing of an operation room seen from a left side surface,  FIG. 15B  being a drawing when the operation room of  FIG. 15A  is seen from above,  FIG. 15C  being a drawing when the operation room of  FIG. 15A  is seen from below. 
   The hydraulic signal output device  90  is accommodated in a rectangular parallelepiped lever stand  80  that is long in an up and down direction. The hydraulic signal output device  90  includes the PPC valve  50 , the block  110  and the EPC valve  60 . 
   There is disposed the shuttle valve  30  in the block  110  as explained in FIG.  1 . 
   The PPC valve  50  includes four pressure-reducing valves  14  as explained in  FIG. 1 , and in each of the pressure-reducing valves  14  a spool  15  is accommodated sliding-free. The PPC valve  50  is attached to a top surface of a top plate  111  of the block  110  so that the spool  15  therein may slide in an up and down direction. 
   On the other hand, as shown in  FIG. 1 , the EPC valve  60  includes the electromagnetic solenoid  61  and the pressure-reducing valve  27 . In the present embodiment, corresponding to the four pressure-reducing valves  14 , four EPC valves  60  are disposed. In the electromagnetic solenoid  61 , as shown in  FIG. 1 , the plunger  26  that is actuated according to the electrical signal is accommodated sliding-free. 
   The electromagnetic solenoid  61  that constitutes the EPC valve  60  is attached to a bottom surface of a bottom plate  112  of the block  110  so that the plunger  26  therein may slide in an up and down direction. Thus, the EPC valve  60  is placed downward from the PPC valve  50  so that the spool  15  and the plunger  26  may be in a parallel relationship, and the PPC valve  50  and the EPC valve  60  are integrally formed. 
   Accordingly, according to the present fifth embodiment, since the PPC valve  50  and the EPC valve  60  are integrally formed along an up and down direction so that the spool  15  and the plunger  26  may be in parallel, the hydraulic signal output device  90  itself can be formed longer in an up and down direction and smaller in a lateral direction. Accordingly, even when the lever stand  80  is smaller in a lateral direction, the hydraulic signal output device  90  can be accommodated inside of the lever stand  80 . 
   In the present embodiment, as shown in  FIGS. 15A and 15C , in the block  110  of the hydraulic signal output device  90 , an output port  115  for externally outputting a hydraulic signal is formed. In accordance with the hydraulic signal outputted from the output port  115 , an operation valve is operated. The operation valve is disposed behind the lever stand  80 . The output port  115  and the operation valve are connected with a pipe line  19  (shown with a dashed line). 
   The output port  115  is disposed backward on a bottom surface of a bottom plate  112  of the block  110 . That is, the output port  115  is disposed toward the operation valve side of various positions on the block  110 . 
   Thus, in the present embodiment, the output port  115  is disposed on a side facing a place where the operation valve is disposed. Accordingly, when the pipe line  19  is routed, the output port can be connected to the operation valve at the shortest distance, and there is no need of circumventing obstacles such as the electromagnetic solenoid  61  and so on disposed on the bottom plate  112  of the block  110 . As a result, since the pipe line  19  can be efficiently routed, the pipe line can be easily configured. 
   In the present embodiment, the output port  115  is disposed backward on the bottom plate  112  of the block  110 . However, as shown in  FIG. 15A , the output port  115  may be disposed on a side plate  117  behind the block  110  and the pipe line  19  (shown with a chain line) may be routed to the operation valve at the backward. 
   In the present embodiment, as shown in  FIG. 15C , four EPC valves  60  are disposed in parallel with an inner wall surface of the lever stand  80 . 
   Accordingly, according to the present embodiment, even when the lever stand  80  is small in a width, the hydraulic signal output device  90  can be accommodated inside of the lever stand  80 . 
   In the present embodiment, as shown in  FIG. 15C , on the bottom plate  112  of the block  110 , in close proximity to the EPC valve  60  a bolt  113  is disposed for fixing other member. On the other hand, when the electromagnetic solenoid  61  of the EPC valve  60  is fixed onto the bottom plate  112  of the block  110  of the hydraulic signal output device  90 , two bolts  65   a  and  65   b  are used. 
   In order for the bolt  113  not to interfere with the bolts  65   a  and  65   b , in an arrangement mode as shown in  FIG. 16 , the bolts  65   a  and  65   b  are arranged. That is, when the electromagnetic solenoid  61  of the EPC valve  60  is fixed, on an axis L along a diameter direction of the EPC valve  60 , that is, on an axis L going through a center C 1  of the EPC valve  60 , one bolt  65   b  is disposed, and the other bolt  65   a  is disposed off-set from the axis L. 
   As a result, an existing bolt  113  and the bolt  65   a  for use in attachment of the EPC valve are hindered from interfering. 
     FIG. 17  shows a sixth embodiment that is a modification of the fifth embodiment.  FIGS. 17A through 17C  correspond to  FIGS. 15A through 15C  and show a side view, a plan view, and a bottom view, respectively, of a hydraulic signal output device  91  according to the sixth embodiment. 
   Four EPC valves  60  that constitute the hydraulic signal output device  91 , as shown in  FIG. 17C , are disposed at a position that is rotated by 45 degree with respect to the positional relationship shown in FIG.  15 C. That is, an arrangement direction of adjacent EPC valves  60  is at 45 degree with respect to an inner wall surface of the lever stand  80  and is not in parallel with the inner wall surface different from FIG.  15 C. 
     FIGS. 18A through 18C  show a seventh embodiment, correspond to  FIGS. 15A through 15C  and show a side view, a plan view and a bottom view, respectively, of the hydraulic signal output device  92  according to the seventh embodiment. 
   In the present embodiment, as shown in  FIGS. 18A and 18B , the PPC valve  50  is attached to a top surface of the top plate  111  of the block  110  so that the spool  15  ( FIG. 1 ) inside of the PPC valve  50  may slide in an up and down direction. On the other hand, the electromagnetic solenoid  61  that constitutes the EPC valve  60  is attached to a top surface of the top plate  111  of the block  110  so that the plunger  26  ( FIG. 1 ) therein may slide in an up and down direction. Thus, the electromagnetic solenoid  61  that constitutes the EPC valve  60  is disposed at a height substantially same as the PPC valve  50  so that the spool  15  and the plunger  26  may be in parallel, and the PPC valve  50  and the EPC valve  60  are integrally formed. 
   According to the present embodiment, the electromagnetic solenoid  61  that constitutes the EPC valve  60  is disposed at a height substantially same as the PPC valve  50  so that the spool  15  and the plunger  26  may be in parallel, and the PPC valve  50  and the EPC valve  60  are integrally formed. Accordingly, the hydraulic signal output device  92  itself can be formed shorter in an up and down direction. As a result, even when the lever stand  80  is lower in height, the hydraulic signal output device  92  can be accommodated in the lever stand  80 . 
   In the present embodiment, the electromagnetic solenoid  61  is disposed at a height substantially same as the PPC valve  50 . However, an entirety of the EPC valve  60 , that is, the electromagnetic solenoid  61  and the pressure-reducing valve  27  (FIG.  1 ), may be disposed at a height substantially same as the PPC valve  50 . 
   Furthermore, in the present embodiment, similarly to the fifth embodiment shown in  FIG. 15 , the output port  115  is disposed backward on the bottom surface of the bottom plate  112  of the block  110 . That is, the output port  115  is disposed toward the operation valve side of various places of the block  110  (FIGS.  18 A and  18 C). 
   Thus, in the present embodiment, since the output port  115  is disposed on a side that faces an arrangement position of the operation valve, of various positions of the block  110 , when the pipe line  19  is routed, the output port  115  can be connected to the operation valve at the shortest distance. Accordingly, the pipe line can be efficiently routed, resulting in an easy pipe line configuration. 
   In the present embodiment, the output port  115  is disposed backward on the bottom plate  112  of the block  110 . However, as shown in  FIG. 18A , the output port  115  may be disposed on a side plate  117  behind the block  110 , and the pipe line  19  (shown with a chain line) may be routed to the backward operation valve. 
     FIGS. 19A through 19C  show an eighth embodiment, correspond to  FIGS. 15A through 15C , and are a side view, a plan view and a bottom view, respectively, of a hydraulic signal output device  93  according to the eighth embodiment. 
   In the present embodiment, as shown in  FIGS. 19A and 19B , the PPC valve  50  is attached to a top surface of the top plate  111  of the block  110  so that the spool  15  ( FIG. 1 ) inside of the PPC valve  50  may slide in an up and down direction. On the other hand, the electromagnetic solenoids  61  that constitute the EPC valve  60  are attached to side surfaces of side plates  116  and  117  of the block  110  so that the plunger  26  ( FIG. 1 ) therein may slide in a fore and aft direction. Thus, the PPC valve  50  and the EPC valve  60  are integrally formed so that the plunger  26  may be in a perpendicular relation with respect to the spool  15 . 
   According to the present embodiment, since the PPC valve  50  and the EPC valve  60  are integrally formed so that the plunger  26  may be in a perpendicular relation with respect to the spool  15 , the hydraulic signal output device  93  can be made larger in a width and shorter in an up and down direction. Accordingly, the hydraulic signal output device  93  can be accommodated in the lever stand  80  that is lower in height but larger in width. 
   In the present embodiment, as shown in  FIG. 19B , the electromagnetic solenoid  61  is attached to the block  110  so that the plunger  26  therein may slide in a fore and aft direction. However, as shown with a dashed line, the electromagnetic solenoid  61  may be attached to the block  110  so that the plunger  26  therein may slide from side to side. 
   In the present embodiment, the electromagnetic solenoid  61  is disposed sideward to the PPC valve  50 . However, an entirety of the PPC valve  60 , that is, the electromagnetic solenoid  61  and the pressure-reducing valve  27  ( FIG. 1 ) may be disposed sideward to the PPC valve  50 . 
   Furthermore, in the present embodiment, similarly to the fifth embodiment shown in  FIG. 15 , the output port  115  is disposed backward on the bottom surface of the bottom plate  112  of the block  110 . That is, the output port  115  is disposed toward the operation valve side of various positions of the block  110 . ( FIG. 19A ,  19 B) 
   Thus, in the present embodiment, since the output port  115  is disposed on a side that faces a position where the operation valve is disposed, of various positions of the block  110 , when the pipe line  19  is routed, the output port  115  can be connected to the operation valve at the shortest distance. Accordingly, the pipe line can be efficiently routed, resulting in an easy pipe line configuration. 
   In the present embodiment, the output port  115  is disposed behind the bottom plate  112  of the block  110 . However, as shown in  FIG. 19A , the output port  115  may be disposed on a side plate  117  at the backward of the block  110 , and the pipe line  19  (shown with a dashed line) may be routed to the operation valve at the backward.