JP2006194352A - Logic valve, composite valve and hydraulic system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a logic valve with an oil amount control circuit having reduced assembling man-hours and a reduced size as required, and to provide a composite valve and a hydraulic system. <P>SOLUTION: A first logic valve 22 comprises a first poppet 48 for opening/closing a discharge oil path 36d and a first oil chamber 52 for giving inner pressure to the back face of the first poppet 48. In the first poppet 48, a first piston rod 50 is arranged to be operated with the inner pressure of the first oil chamber 52. On the other hand, a second logic valve 24 comprises a second poppet 80 for opening/closing a suction oil path 36e and a second oil chamber 84 for giving inner pressure to the back face of the second poppet 80. In the second poppet 80, a second piston rod 82 is arranged to be operated with the inner pressure of the second oil chamber 84. The second logic valve 24 is operated to be opened by the first piston rod 50, and the first logic valve 22 is operated to be opened by the second piston rod 82. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a logic valve and a composite valve that constitute an oil amount adjusting circuit that adjusts excess or deficiency of pressure oil in a closed circuit, and a hydraulic system including an oil amount adjusting circuit.

  The inside of the cylinder constituting the hydraulic cylinder is divided into a pressurizing chamber and a return chamber by a piston rod, and the capacity of the return chamber in which the rod portion of the piston rod is accommodated is smaller than the capacity of the pressurizing chamber. It is normal. Therefore, in a closed circuit hydraulic system that operates a hydraulic cylinder using a two-way hydraulic pump, the amount of pressure oil supplied to the pressurizing chamber during the pressurizing operation is the amount of pressure oil supplied to the return chamber during the return operation. There was a problem that the amount of pressure oil was excessive and insufficient in the closed circuit. That is, the pressure oil returned from the return chamber to the pump is insufficient during the pressurization operation, and the pressure oil returned from the pressurization chamber to the pump is excessive during the return operation, and therefore, between the suction side and the discharge side of the pump. There was a risk that not only would the pump be damaged by this pressure difference but also the hydraulic circuit would not be established.

Therefore, conventionally, an oil amount adjustment circuit (liquid amount compensation circuit) that adjusts the excess or deficiency of pressure oil by combining existing components such as a shuttle valve, pilot check valve, check valve and relief valve in a closed circuit (Patent Document 1).
JP 2002-139003 A (see FIGS. 14 to 17 of the publication)

  In the past (Patent Document 1), an oil amount adjustment circuit (liquid amount compensation circuit) is configured by combining existing components, so the components must be connected to each other by piping or a circuit configuration board (manifold). It took a lot of man-hours and installation space. In addition, the shuttle valve, pilot check valve, check valve, relief valve, and the like become larger as the required amount of oil increases, so that it has not been possible to meet the demand for downsizing of the hydraulic system.

  Therefore, a main object of the present invention is to provide a logic valve, a composite valve, and a hydraulic system that can reduce the number of assembly steps of the oil amount adjusting circuit and can meet the demand for downsizing.

  According to the first aspect of the present invention, “a logic having poppets 48, 80 that open and close the oil passages 36 d, 36 e and oil chambers 52, 84 configured to allow internal pressure to act on the back surfaces of the poppets 48, 80. In the valves 22, 24, piston rods 50, 82 that receive the internal pressure of the oil chambers 52, 84 are arranged inside the poppets 48, 80, and the rod portions 50 b, 82 b constituting the piston rods 50, 82 are poppets. The logic valves 22 and 24 "are characterized in that they protrude outward from the tip portions of 48 and 80".

  In the present invention, when the internal pressure of the oil chambers 52 and 84 rises, the piston rods 50 and 82 disposed inside the poppets 48 and 80 are pressed, and the rod portions 50b and 82b are pushed out from the tip portions of the poppets 48 and 80. It is. Therefore, when the poppets 80 and 48 of the other valves 24 and 22 are arranged ahead of the rod portions 50b and 82b, the poppets 80 and 48 of the other valves 24 and 22 are pressed in the opening direction by the rod portions 50b and 82b. can do.

  According to the second aspect of the present invention, “a first valve 22 having a first poppet 48 that opens and closes the oil passage 36 d and a first oil chamber 52 configured to allow internal pressure to act on the back surface of the first poppet 48. And a second valve 24 having a second poppet 80 for opening and closing the oil passage 36e, and a second valve 24 arranged opposite to the first valve 22, wherein the first poppet 48 includes The first piston rod 50 that receives the internal pressure of the first oil chamber 52 is disposed, and the second poppet 80 is pressed in the opening direction by the first rod portion 50b constituting the first piston rod 50. It is.

  In the present invention, when the internal pressure of the first oil chamber 52 in the first valve 22 increases, the first piston rod 50 disposed inside the first poppet 48 is pressed, and the first rod from the tip of the first poppet 48 is pressed. Part 50b is extruded. Then, when the second poppet 80 is pressed directly or indirectly by the first rod portion 50b, the second valve 24 is opened.

  According to a third aspect of the present invention, in the "composite valve 10" according to the second aspect, the "second valve 24 is configured so that an internal pressure can be applied to the back surface of the second poppet 80." 84, and a second piston rod 82 that receives the internal pressure of the second oil chamber 84 is disposed inside the second poppet 80, and the second rod portion 82b that constitutes the second piston rod 82 The first poppet 48 is pressed in the opening direction ".

  In the present invention, the second valve 24 is opened by the first rod portion 50 b of the first piston rod 50 constituting the first valve 22, and the second rod of the second piston rod 82 constituting the second valve 24. The first valve 22 is opened by the portion 82b.

  The invention described in claim 4 is the "composite valve 10" described in claim 2 or 3, wherein "one end communicates with the pressurizing chamber 32a of the hydraulic cylinder 16 and the other end is one of the two-way hydraulic pump 14. A pressure side oil passage 36a that communicates with the other port 34a, a return side oil passage 36b that communicates with one end of the return chamber 32b of the hydraulic cylinder 16, and the other end communicates with the other port 34b of the two-way hydraulic pump 14. A suction oil passage 36c that communicates with the pressure oil tank 18, a discharge oil passage 36d that communicates the pressure side oil passage 36a and the suction and exhaust oil passage 36c, and a return side oil passage 36b and the intake and exhaust oil passage 36c. A main body portion 26 having a suction oil passage 36e, the first valve 22 and the second valve 24 are incorporated in the main body portion 26, and the discharge oil passage 36d is opened and closed by a first poppet 48, Oil passage 36e is second Is opened and closed by a pet 80 "it is characterized.

  In the present invention, when the second valve 24 is opened, the suction oil passage 36e is opened, and the shortage of pressure oil returned from the return chamber 32b of the hydraulic cylinder 16 to the two-way hydraulic pump 14 is the pressure oil tank 18. To the suction side of the two-way hydraulic pump 14 through the intake / exhaust oil passage 36c and the suction oil passage 36e. On the other hand, when the first valve 22 is opened, the discharge oil passage 36d is opened, and excess hydraulic oil returned from the pressurizing chamber 32a of the hydraulic cylinder 16 to the two-way hydraulic pump 14 is discharged to the discharge oil passage 36d and The oil is discharged to the pressure oil tank 18 through the intake / exhaust oil passage 36c.

  According to a fifth aspect of the present invention, in the “composite valve 10” according to any of the second to fourth aspects, the “main body portion 26 includes the first oil chamber 52 of the first valve 22 and the two-way hydraulic pump 14. A first pilot oil passage 68 that communicates with one of the ports 34a; a second pilot oil passage 90 that communicates between the second oil chamber 84 of the second valve 24 and the other port 34b of the two-way hydraulic pump 14; It has a feature.

  In the present invention, when the hydraulic cylinder 16 is pressurized, the pressure oil discharged from one port 34a of the two-way hydraulic pump 14 enters the pressure chamber 32a of the hydraulic cylinder 16 through the pressure side oil passage 36a. Pressure oil is supplied to the first oil chamber 52 of the first valve 22 through the first pilot oil passage 68, and the second valve 24 is opened by the first rod portion 50 b of the first piston rod 50. The shortage is replenished from the pressure oil tank 18. On the other hand, when the hydraulic cylinder 16 is returned, pressure oil discharged from the other port 34b of the two-way hydraulic pump 14 is supplied to the return chamber 32b of the hydraulic cylinder 16 through the return-side oil passage 36b. The excess pressure oil is supplied to the second oil chamber 84 of the second valve 24 through the second pilot oil passage 90, and the first valve 22 is opened by the second rod portion 82b of the second piston rod 82. It is discharged to the pressure oil tank 18.

  The invention described in claim 6 is the “composite valve 10” described in claim 4 or 5, wherein “the relief valve 28 for releasing the internal pressure is provided in the first oil chamber 52 and / or the second oil chamber 84, 30 ”is provided.

    In the present invention, when the internal pressures of the oil chambers 52 and 84 are released from the relief valves 28 and 30, the pressure acting on the back surfaces of the poppets 48 and 80 becomes smaller than the pressure acting on the front end surfaces. By moving 80 in the opening direction, the discharge oil passage 36d or the suction oil passage 36e is opened. Thereby, the internal pressure of the pressure side oil passage 36a or the return side oil passage 36b is released to the pressure oil tank 18, and an abnormal increase in the internal pressure of the closed circuit is suppressed.

  The invention according to claim 7 is the “composite valve 10” according to any one of claims 2 to 6, wherein “the main body portion 26 is formed in a plate shape, and the pressure side oil passage 36a and the return side oil passage are formed. 36b penetrates the main body portion 26 in the thickness direction, and the ports A1, A2, B1, and B2 formed at both ends of the pressure side oil passage 36a and the return side oil passage 36b are opposed to each other. " It is characterized by that.

  In the present invention, the ports A1 and A2 of the pressure side oil passage 36a face each other, and the ports B1 and B2 of the return side oil passage 36b face each other, so the pressure side oil passage 36a and the return side oil The path 36b can be configured almost straight. Therefore, the flow resistance of the pressure oil becomes extremely small, which is suitable for a large hydraulic system 12 that requires a large amount of pressure oil.

  The invention described in claim 8 is “the hydraulic cylinder 16, the two-way hydraulic pump 14 that supplies pressure oil to the hydraulic cylinder 16, and the shortage of pressure oil is replenished from the pressure oil tank 18, The closed circuit hydraulic system 12 includes an oil amount adjusting circuit 20 that discharges excess oil to the pressure oil tank 18, and the oil amount adjusting circuit 20 passes the pressure oil replenished from the pressure oil tank 18. 36e, a discharge oil passage 36d for passing the pressure oil discharged to the pressure oil tank 18, a first valve 22 having a first poppet 48 for opening and closing the discharge oil passage 36d, and a second poppet for opening and closing the suction oil passage 36e. The first poppet 48 has a first piston rod 50 for opening the second valve, and the second poppet 80 has a second valve 24 having a second valve 24 having a second valve 24. 2nd fixie to open 1 valve 22 Rod 82 is arranged, a hydraulic system 12 '.

  In the present invention, when the second valve 24 is opened by the first piston rod 50 constituting the first valve 22, the intake oil passage 36e is opened. Further, when the first valve 22 is opened by the second piston rod 82 constituting the second valve 24, the discharged oil passage 36d is opened.

  According to the first to eighth aspects of the present invention, since the other valve can be opened by the rod portion protruding outward from the tip of the poppet, a mechanism for opening the other valve is separately provided. There is no need. Therefore, when these inventions are applied to the oil amount adjusting circuit, the number of assembling steps can be reduced and the demand for downsizing can be met.

  FIG. 1 is a plan view (A) and a sectional view (B) showing a specific configuration of a composite valve 10 to which the present invention (Claims 2 to 7) is applied. FIG. 2 shows the structure of the composite valve 10. FIG. 3 is a simplified schematic view, FIG. 3 is a sectional view showing the positional relationship between the poppet 48 and the pressure side oil passage 36a, and FIG. 4 is a circuit diagram showing the mechanism of the composite valve 10 with symbols. . 5 is a plan view (A) and a front view (B) showing the hydraulic system 12 to which the present invention (Claim 8) is applied, and FIG. 6 shows the structure of the hydraulic system 12 in a simplified manner. FIG. 7 is a circuit diagram showing the mechanism of the hydraulic system 12 with symbols.

  Here, the hydraulic system 12 (FIGS. 5 to 7) is a closed circuit system that drives the hydraulic cylinder 16 with the pressure oil supplied from the two-way hydraulic pump 14. An oil amount adjusting circuit 20 (FIG. 7) for replenishing the pressure oil shortage from the pressure oil tank 18 and discharging the excess pressure oil to the pressure oil tank 18 is incorporated. The composite valve 10 to which the present invention (Claims 2 to 7) is applied is used as a main part of the oil amount adjusting circuit 20, and the first logic valve 22 to which the present invention (Claim 1) is applied. The second logic valve 24 is used as a component of the composite valve 10.

  As shown in FIGS. 1 to 4, the composite valve 10 includes a main body 26, a first logic valve 22 and a second logic valve 24 incorporated in the main body 26, a first logic valve 22 and a second logic valve. The first relief valve 28 and the second relief valve 30 are arranged on the back side of 24.

  The main body 26 is a substantially rectangular plate-like member having a pressure side oil passage 36a, a return side oil passage 36b, a suction / discharge oil passage 36c, a discharge oil passage 36d, and a suction oil passage 36e. The passage 36c communicates with the exhaust oil passage 36d, and the return-side oil passage 36b and the intake / exhaust oil passage 36c communicate with each other through the intake oil passage 36e. More specifically, the intake / exhaust oil passage 36c is formed so as to penetrate the main body portion 26 in the thickness direction, and the pressurizing side oil passage 36a and the return side oil passage 36b are located at the positions sandwiching the intake / exhaust oil passage 36c. 26 is formed in the thickness direction. The discharge oil passage 36d is formed perpendicular to the pressure side oil passage 36a and the intake / exhaust oil passage 36c, and the intake oil passage 36e is connected to the return side oil passage 36b and the intake / exhaust oil. It is formed perpendicular to these so as to communicate with the path 36c.

  The one end of the pressurizing side oil passage 36a is formed with a port A1 communicating with the pressurizing port a formed in the pressurizing chamber 32a of the hydraulic cylinder 16, and the other end of the pressurizing side oil passage 36a is formed at the other end. A port A2 communicated with one port 34a of the two-way hydraulic pump 14 is formed to face the port A1. Further, a port B1 communicating with the return port b formed in the return chamber 32b of the hydraulic cylinder 16 is formed at one end of the return side oil passage 36b. A port B2 communicated with the other port 34b of the directional hydraulic pump 14 is formed to face the port B1. Further, a port T communicating with the pressure oil tank 18 is formed at one end of the intake / exhaust oil passage 36c, and the other end of the intake / exhaust oil passage 36c is communicated with the drain port 14c of the two-way hydraulic pump 14. The port Dr is formed to face the port T. Therefore, the pressure side oil passage 36a, the return side oil passage 36b, and the intake / exhaust oil passage 36c penetrate the main body portion 26 almost straight in the thickness direction, and the flow resistance of the pressure oil is suppressed to be extremely small.

  In addition, a first logic valve chamber 38 constituting the first logic valve 22 is formed at a position facing the discharge oil passage 36d across the pressure side oil passage 36a inside the main body 26, and the return side A second logic valve chamber 40 constituting the second logic valve 24 is formed at a position facing the suction oil passage 36e across the oil passage 36b.

  A first relief valve chamber 42 constituting the first relief valve 28 is formed on the back side of the first logic valve chamber 38, and a second relief valve is formed on the back side of the second logic valve chamber 40. A second relief valve chamber 44 constituting 30 is formed. Furthermore, a connection hole 46 (FIG. 1A) through which a bolt (not shown) for connecting the other components constituting the hydraulic system 12 (FIG. 5) and the composite valve 10 is passed through the corner of the main body 26. )) Is formed.

  The first logic valve 22 includes a first poppet 48 slidably disposed within the first logic valve chamber 38, a first piston rod 50 disposed within the first poppet 48, and a first logic valve chamber. The first oil chamber 52 secured behind the first poppet 48 in the interior 38 and a coil spring 54 that presses the first poppet 48 in the closing direction.

  The first poppet 48 is a hollow cylindrical member having an outer surface along the inner surface of the first logic valve chamber 38, and the outer periphery of the tip of the first poppet 48 contacts the inner periphery (that is, the valve seat) of the discharge oil passage 36 d. It is formed in a tapered shape so as to obtain. An oil passage 56 is formed on the outer periphery of the tip to communicate the drain oil passage 36d and the internal space S of the first poppet 48. The first piston rod 50 has a first passage at the center of the tip. A through hole 58 through which the rod portion 50b is inserted is formed. Further, a lid body 60 having a through hole 60 a at the center is fixed to the rear end opening of the first poppet 48. Accordingly, when the first oil chamber 52 is filled with the pressure oil, the internal pressure of the first oil chamber 52 acts on the back surface of the lid 60, that is, the first poppet 48.

  The first piston rod 50 has a first piston portion 50a that slides inside the first poppet 48, and a first rod portion 50b that extends from the first piston portion 50a, and the outer periphery of the first piston portion 50a. A seal ring 62 is attached to the surface. The first rod portion 50b protrudes to the outside from a through hole 58 formed in the center of the tip of the first poppet 48. The first rod portion 50b has a first rod portion 50b around the first rod portion 50b. A coil spring 64 for pushing back the piston rod 50 against the internal pressure of the first oil chamber 52 is disposed.

  The first oil chamber 52 is configured to allow internal pressure to act on the back surface of the first poppet 48, and the first oil chamber 52 and the first relief valve chamber 42 are provided at the bottom of the first oil chamber 52. An oil passage 66 that communicates with the first oil chamber 52 is formed, and a first pilot oil passage 68 that communicates between the first oil chamber 52 and one port 34 a of the two-way hydraulic pump 14 is formed at the side of the first oil chamber 52. Is formed. The oil passage 66 and the first pilot oil passage 68 are provided with orifices 70a and 70b for adjusting the hole diameters.

  The first relief valve 28 adjusts the first poppet 72 that opens and closes the oil passage 66 in the first relief valve chamber 42, the coil spring 74 that presses the first poppet 72 in the closing direction, and the pressing force of the coil spring 74. An oil passage 78 is formed in the side portion of the first relief valve chamber 42 to communicate the first relief valve chamber 42 with the intake / exhaust oil passage 36c.

  The first relief valve 28 opens the first logic valve 22 by releasing the internal pressure of the first oil chamber 52 when the internal pressure of the pressurization side oil passage 36a abnormally increases, and the pressure of the pressurization side oil passage 36a is reduced. It has a function of escaping to the pressure oil tank 18. In order to effectively exhibit this function, the hole diameter of the orifice 70 a attached to the oil passage 66 is set larger than the hole diameter of the orifice 70 b attached to the first pilot oil passage 68. The function of the first relief valve 28 will be described later.

  The second logic valve 24 is disposed inside the main body portion 26 so as to face the first logic valve 22 so as to open and close the suction oil passage 36e. The specific configuration of the second logic valve 24 is as follows. This is the same as the one logic valve 22. That is, the second logic valve 24 includes a second poppet 80 slidably disposed in the second logic valve chamber 40, a second piston rod 82 disposed in the second poppet 80, and a second logic. The valve chamber 40 includes a second oil chamber 84 secured behind the second poppet 80 and a coil spring 86 that presses the second poppet 80 in the closing direction. An oil passage 88 communicating with the second oil chamber 84 and the second relief valve chamber 44 is formed at the bottom of the second oil chamber 84. A second pilot oil passage 90 communicating with the two oil chamber 84 and the other port 34b of the two-way hydraulic pump 14 is formed. The oil passage 88 and the second pilot oil passage 90 have a hole diameter thereof. Orifices 92a and 92b for adjustment are mounted.

  The first logic valve 22 and the second logic valve 24 described above are configured so as to be opened by the first piston rod 50 and the second piston rod 82, and the first logic valve 22 and the second logic valve In the state where 24 is closed, a gap is secured between the first rod portion 50b and the second rod portion 82b in order to prevent mutual interference (FIGS. 1B and 2).

  The second relief valve 30 has a function of releasing the pressure of the return side oil passage 36 b to the pressure oil tank 18, and the specific configuration of the second relief valve 30 is the same as that of the first relief valve 28. That is, the second relief valve 30 has a second poppet 94 that opens and closes the oil passage 88 in the second relief valve chamber 44, a coil spring 96 that presses the second poppet 94 in the closing direction, and a pressing force of the coil spring 96. An oil passage 100 that communicates the second relief valve chamber 44 and the intake / exhaust oil passage 36c is formed in a side portion of the second relief valve chamber 44.

  When the hydraulic system 12 (FIGS. 5 to 7) is configured using the composite valve 10, the pressurization port a formed in the pressurization chamber 32a of the hydraulic cylinder 16 is provided as shown in FIGS. The return port b formed in the return chamber 32b of the hydraulic cylinder 16 is communicated with the port B1 of the return side oil passage 36b. Further, one port 34a of the two-way hydraulic pump 14 is communicated with the port A1 of the pressure side oil passage 36a and the port PPA of the first pilot oil passage 68, and the other port 34b of the two-way type hydraulic pump 14 is connected to the return side. The port B2 of the oil passage 36b and the port PPB of the second pilot oil passage 90 are communicated. Further, the drain port 34c of the two-way hydraulic pump 14 is communicated with the port Dr of the intake / exhaust oil passage 36c, and the pressure oil tank 18 is communicated with the port T of the intake / exhaust oil passage 36c.

  When pressurizing the hydraulic cylinder 16 in the hydraulic system 12, as shown in FIG. 8, the pressure oil discharged from the two-way hydraulic pump 14 passes through the pressure side oil passage 36a and the pressure chamber of the hydraulic cylinder 16 is pressed. On the other hand, the pressure oil discharged from the return chamber 32b of the hydraulic cylinder 16 is returned to the two-way hydraulic pump 14 through the return-side oil passage 36b. At this time, the pressure oil discharged from the two-way hydraulic pump 14 is also supplied to the first oil chamber 52 through the first pilot oil passage 68, and the internal pressure of the first oil chamber 52 is increased. Accordingly, in the first logic valve 22, the first poppet 48 and the first piston rod 50 are pressed by the internal pressure of the first oil chamber 52, the discharge oil passage 36 d is closed by the first poppet 48, and the first piston rod 50 opens the second logic valve 24. That is, the second piston rod 82 of the second logic valve 24 is pressed by the first piston rod 50, and accordingly, the second poppet 80 is moved in the opening direction. When the second logic valve 24 is opened, the intake oil passage 36e is opened, so that the pressure oil from the pressure oil tank 18 is supplied to the return-side oil passage 36b through the intake / exhaust oil passage 36c and the intake oil passage 36e, and is closed. The shortage of pressure oil in the circuit is replenished.

  If the internal pressure of the pressure side oil passage 36a rises abnormally while the hydraulic cylinder 16 is being pressurized, as shown in FIG. 9, the first logic valve 22 is opened to open the pressure side oil passage 36a. Is released to the suction side of the two-way hydraulic pump 14. That is, when the internal pressure of the pressure side oil passage 36a abnormally increases, the internal pressure of the first oil chamber 52 also abnormally increases, so that the first relief valve 28 is opened and the oil passage 66 is opened. Then, since the hole diameter of the orifice 70a attached to the oil passage 66 is larger than the hole diameter of the orifice 70b attached to the first pilot oil passage 68, the amount of pressure oil discharged from the oil passage 66 is the first. It becomes larger than the amount of pressure oil taken in from the pilot oil passage 68, and the internal pressure of the first oil chamber 52 rapidly decreases. Therefore, a pressure difference is generated between the internal pressure (low pressure) of the first oil chamber 52 and the internal pressure (high pressure) of the pressure side oil passage 36a, and the first poppet 48 is moved in the opening direction by this pressure difference, and the discharge oil passage 36d is opened and the internal pressure of the pressure side oil passage 36a is released. Thereby, the internal pressure of the pressure side oil passage 36a is instantaneously returned to the normal pressure, and the entire circuit of the hydraulic system 12 is protected.

  When the return operation of the hydraulic cylinder 16 is performed, the two-way hydraulic pump 14 is reversely rotated, and the hydraulic oil discharged from the two-way hydraulic pump 14 passes through the return-side oil passage 36b as shown in FIG. On the other hand, the pressure oil discharged from the pressurizing chamber 32a of the hydraulic cylinder 16 is returned to the two-way hydraulic pump 14 through the pressurizing side oil passage 36a. At this time, the pressure oil discharged from the two-way hydraulic pump 14 is also supplied to the second oil chamber 84 through the second pilot oil passage 90, and the internal pressure of the second oil chamber 84 is increased. Accordingly, in the second logic valve 24, the second poppet 80 and the second piston rod 82 are pressed by the internal pressure of the second oil chamber 84, the suction oil passage 36e is closed by the second poppet 80, and the second piston rod The first logic valve 22 is opened by 82. That is, the first piston rod 50 of the first logic valve 22 is pressed by the second piston rod 82, and accordingly, the first poppet 48 is moved in the opening direction. When the first logic valve 22 is opened, the discharge oil passage 36d is opened, so that excess pressure oil in the closed circuit is discharged to the pressure oil tank 18 through the discharge oil passage 36d and the intake / discharge oil passage 36c.

  If the internal pressure of the return side oil passage 36b abnormally rises during the return operation of the hydraulic cylinder 16, as shown in FIG. 11, the second logic valve 24 is opened to open the return side oil passage 36b. The internal pressure is released to the suction side of the pressure oil tank 18 or the two-way hydraulic pump 14. That is, when the internal pressure of the return side oil passage 36b abnormally increases, the internal pressure of the second oil chamber 84 also abnormally increases, so that the second relief valve 30 is opened and the oil passage 88 is opened. Then, since the hole diameter of the orifice 92a attached to the oil passage 88 is larger than the hole diameter of the orifice 92b attached to the second pilot oil passage 90, the amount of the pressure oil discharged from the oil passage 88 is the second. It becomes larger than the amount of pressure oil taken in from the pilot oil passage 90, and the internal pressure of the second oil chamber 84 rapidly decreases. Therefore, a pressure difference is generated between the internal pressure (low pressure) of the second oil chamber 84 and the internal pressure (high pressure) of the return side oil passage 36b, and the second poppet 80 is moved in the opening direction by this pressure difference, and the suction oil passage 36e is opened and the internal pressure of the return side oil passage 36b is released. As a result, the internal pressure of the return-side oil passage 36b is instantaneously returned to the normal pressure, and the entire circuit of the hydraulic system 12 is protected.

  In the above-described embodiment, the first logic valve 22, the second logic valve 24, the first relief valve 28, and the second relief valve 30 are integrally incorporated in the main body 26, but as shown in FIG. The first logic valve 22 and the second logic valve 24 may be incorporated in the main body 26, and the first relief valve 28 and the second relief valve 30 may be configured independently using existing components.

  Further, in the above-described embodiment, the first rod portion 50b of the first piston rod 50 and the second rod portion 82b of the second piston rod 82 are abutted, but as shown in FIG. The rod portion 50b may be brought into contact with the second poppet 80, and the second rod portion 82b may be brought into contact with the first poppet 48.

  Further, the “composite valve” of the present invention may be applied to uses other than the oil amount adjustment circuit 20 (FIG. 7) of the hydraulic system 12. In that case, one of the two opposed valves may be a normal type logic valve 102 as shown in FIG. 14, or may be a valve 104 different from the logic valve as shown in FIG. Even in these cases, since the opposing valve 102 or 104 can be opened by the logic valve 108 including the piston rod 106, the entire hydraulic system can be reduced in size compared with the case where a separate opening operation mechanism is provided. Can do.

  Furthermore, the “logic valve” of the present invention may be applied to uses other than the composite valve. In other words, the “logic valve” of the present invention is characterized in that it includes a piston rod for operating other system elements, and focusing on this point, system elements other than the valve (such as a pressure sensitive switch) are connected to the piston rod. It is also possible to operate.

A plan view (A) and a sectional view (B) showing a specific configuration of the composite valve Simplified diagram showing the structure of the compound valve Sectional drawing which shows the positional relationship of a poppet and a pressure side oil path Circuit diagram showing the mechanism of the compound valve with symbols A plan view (A) and a front view (B) showing a hydraulic system using a compound valve Simplified diagram showing the structure of the hydraulic system Circuit diagram showing the mechanism of the hydraulic system with symbols The figure which shows operation of the hydraulic system at the time of pressurization operation Diagram showing pressure release operation during pressurization operation The figure which shows operation of the hydraulic system at the time of return operation Diagram showing pressure release operation during return operation Simplified diagram showing compound valve with independent relief valve Simplified view showing a compound valve with the rod part in contact with the poppet Simplified diagram showing a compound valve using a normal logic valve on one of the opposing valves Simplified diagram showing a compound valve using a valve other than a logic valve on one of the opposing valves

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Composite valve 12 ... Hydraulic system 14 ... Two-way type hydraulic pump 16 ... Hydraulic cylinder 18 ... Pressure oil tank 20 ... Oil amount adjustment circuit 22 ... 1st logic valve 24 ... 2nd logic valve 26 ... Main-body part 28 ... 1st Relief valve 30 ... Second relief valve 36a ... Pressure side oil passage 36b ... Return side oil passage 36c ... Suction / discharge oil passage 36d ... Discharge oil passage 36e ... Suction oil passage 38 ... First logic valve chamber 40 ... Second logic valve chamber 42 1st relief valve chamber 44 2nd relief valve chamber 48 1st poppet 50 1st piston rod 50a 1st piston portion 50b 1st rod portion 52 1st oil chamber 68 1st pilot oil passage 80 Second poppet 82 Second piston rod 84 Second oil chamber 90 Second pilot oil passage 102 Normal type logic valve 104 Valve 106 different from logic valve Piston Head 108 ... logic valve

Claims (8)

In a logic valve having a poppet that opens and closes an oil passage, and an oil chamber configured to allow internal pressure to act on the back surface of the poppet,
A piston rod that receives the internal pressure of the oil chamber is disposed inside the poppet, and a rod portion that constitutes the piston rod protrudes outward from a tip portion of the poppet. valve. A first valve having a first poppet that opens and closes an oil passage and a first oil chamber configured to allow internal pressure to act on the back surface of the first poppet; and a second poppet that opens and closes the oil passage; A composite valve comprising a second valve disposed opposite the first valve,
A first piston rod that receives the internal pressure of the first oil chamber is disposed inside the first poppet, and the second poppet is pressed in the opening direction by a first rod portion that constitutes the first piston rod. A compound valve.   The second valve has a second oil chamber configured to allow an internal pressure to act on the back surface of the second poppet, and the internal pressure of the second oil chamber is set inside the second poppet. The composite valve according to claim 2, wherein a second piston rod to be received is arranged, and the first poppet is pressed in an opening direction by a second rod portion constituting the second piston rod. One end communicates with the pressurizing chamber of the hydraulic cylinder, the other end communicates with one port of the two-way hydraulic pump, one end communicates with the return chamber of the hydraulic cylinder, and the other end A return-side oil passage communicated with the other port of the two-way hydraulic pump, an intake / exhaust oil passage communicated with a pressure oil tank, a discharge oil passage communicating the pressure-side oil passage and the intake / exhaust oil passage, A main body having an intake oil passage that communicates the return-side oil passage and the intake / exhaust oil passage;
The first valve and the second valve are incorporated in the main body, the discharge oil passage is opened and closed by the first poppet, and the suction oil passage is opened and closed by the second poppet. The composite valve according to 2 or 3.   The main body includes a first pilot oil passage that communicates the first oil chamber of the first valve and one port of the two-way hydraulic pump, the second oil chamber of the second valve, and the 2 5. The composite valve according to claim 2, further comprising a second pilot oil passage communicating with the other port of the directional hydraulic pump.   The composite valve according to claim 4 or 5, wherein a relief valve for releasing an internal pressure is provided in the first oil chamber and / or the second oil chamber.   The body portion is formed in a plate shape, and the pressure side oil passage and the return side oil passage are formed through the body portion in the thickness direction, and the pressure side oil passage and the return side oil passage are formed. The composite valve according to any one of claims 2 to 6, wherein the ports formed at both ends of the path face each other. Hydraulic cylinder, two-way hydraulic pump for supplying pressure oil to the hydraulic cylinder, and oil amount adjustment for replenishing insufficient pressure oil from the pressure oil tank and discharging excess pressure oil to the pressure oil tank A closed circuit hydraulic system comprising a circuit,
The oil amount adjustment circuit opens and closes a suction oil passage for passing pressure oil replenished from the pressure oil tank, a discharge oil passage for passing pressure oil discharged to the pressure oil tank, and a first opening and closing the discharge oil passage. A first valve having a poppet and a second valve having a second poppet for opening and closing the suction oil passage; and a first piston rod for opening the second valve inside the first poppet Is arranged, and a second piston rod for opening the first valve is arranged inside the second poppet.

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