JP4372444B2 - Booster valve device and hydraulic cylinder device using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a speed increasing valve device suitable for use in a hydraulic drive bending apparatus or the like.In placeRelated.
[0002]
[Prior art and problems to be solved by the invention]
In a double-acting hydraulic cylinder device in which the rod of the hydraulic piston protrudes from one end side of the hydraulic cylinder, when the hydraulic cylinder is driven in the direction in which the piston rod protrudes from the hydraulic cylinder, 2. Description of the Related Art A speed increasing valve device that allows oil flowing out from a rod side chamber to be introduced into a chamber of a hydraulic cylinder head is known.
[0003]
  As shown in FIGS. 5A to 5C, the speed increasing valve device 110 includes a head side port L1 and a rod side port of the double acting hydraulic cylinder 101 at the load side port or the outlet ports V1 and V2. Connected to L2. Note that the hydraulic pressure source side port or inlet ports U1 and U2 of the speed increasing valve device 110 are connected to a hydraulic pressure source (not shown) via a switching valve (not shown). One inlet port U1 of the speed increasing valve device 110 and the head side outlet port V1 are directly connected by a flow path 111. Between the other inlet port U2 and the rod-side outlet port V2, a pilot operation check that communicates between the inlet port U2 and the rod-side outlet port V2 when the hydraulic pressure of the head-side outlet port V1 exceeds a predetermined level. A valve 120 is provided, and between the outlet ports V1 and V2, the flow of pressure oil from the rod side outlet port V2 to the head side outlet port V1 can be allowed.RuAn pilot operation check valve 130 is provided. The speed increasing device 110 further includes a rod side outlet port V2.And paThe extension control position SP1, the inlet port U2, and the rod-side outlet port V2 are directly communicated with each other through the communication path R2 and the pilot check valve 130 is communicated with the communication path R1 and the inlet port U2 is closed with the blocking portion T1.SepaThe spool valve 140 includes a spool 141 that is movable between a contraction control position SP2 that closes the inlet side of the pilot operation check valve 130 with a blocking portion T2. The spool 141 receives a biasing force toward the extension control position SP1 by the hydraulic pressure of the port U2 and the spring 142, and receives a force toward the contraction control position by the hydraulic pressure of the ports U1 to V1.
[0004]
  When the inlet port U1 is connected to a hydraulic pump (not shown) and the inlet port U2 is connected to an oil reservoir (not shown) by the operation of an inlet side switching valve (not shown), FIG. ), The spool valve 140 is set to the extension control position SP1, and the pressure oil flows into the head side oil chamber 102 via the head side port L1 and discharges the oil in the rod side oil chamber 103. This oil passes through the communication path R1 of the spool 141 of the spool valve 140.RipaThe pilot operation check valve 130 is opened to enter the head side oil chamber 102 from the outlet port V1. On the other hand, when the load is small, the pressure in the head-side oil chamber 102 is relatively low, so that the pilot operated check valve 120 is kept closed. Accordingly, since the oil flowing out from the rod side oil chamber 103 along with the supply of the pressure oil to the head side oil chamber 102 also enters the head side oil chamber 102, the speed increasing operation is performed so that the rod 104 protrudes at a relatively high speed. .
[0005]
  When the load increases, as shown in FIG. 5B, the pressure of the hydraulic oil in the head side oil chamber 102 and the flow path 111 communicating with the head side oil chamber 102 increases,, PaThe pilot operated check valve 130 is closed, while the pilot operated check valve 120 is opened. Accordingly, the port V2 communicates with the port U2 connected to the oil reservoir (not shown), and the oil in the rod side oil chamber 103 flows out through the pilot check valve 120 toward the port U2.
[0006]
On the other hand, when the inlet port U2 is connected to the hydraulic pump (not shown) and the inlet port U1 is connected to the oil reservoir (not shown) by the operation of the switching valve (not shown) on the inlet side, FIG. As shown in (c), the spool valve 140 is set to the contraction control position SP2, and the pressure oil flows into the rod-side oil chamber 103 through the rod-side port L2 to discharge the oil in the head-side oil chamber 102. . On the other hand, since the pressure in the head-side flow path 111 is low, the pilot operation check valve 120 is kept closed. Accordingly, the oil flowing out from the head side oil chamber 102 returns to the oil reservoir (not shown) as pressure oil is supplied to the rod side oil chamber 103.
[0007]
In the operation of the speed increasing valve 110 as described above, it is indispensable that the operation control of communication / blocking between the flow paths by the spool valve 140 is surely performed.
[0008]
Incidentally, the speed increasing circuit 110 schematically shown in FIGS. 5A to 5C actually adopts a structure as shown in FIGS. 5D and 5E, for example. That is, the spool 141 constituting the valve body of the spool valve 140 includes two large diameter portions or land portions 143 and 144 and an intermediate small diameter portion 145, and the valve box 150 slides the spool 141 in the longitudinal directions A1 and A2. It has a hole 151 that is movably accommodated. The hole 151 of the valve box 150 has an inner diameter such that the land portions 143 and 144 of the spool 141 are in sliding contact with each other, and has annular recesses 152, 153, and 154 that form large-diameter hole portions at portions to be ports.
[0009]
When the spool 141 is at the extension control position SP1 shown in FIG. 5D, the annular grooves 152 and 153 communicate with each other via the annular space 155 between the small diameter portion 145 and the hole 151 of the spool 141, and the land portion. 143 is in close contact with the peripheral surface 151 a on the left side of the hole 151 and closes the hole 151 on the left side of the hole 151, and the left side part of the land part 144 closes the hole 151 between the annular groove part 153 and the annular groove part 154. In this case, the communication passage R1 shown in FIGS. 5A and 5B corresponds to the annular groove portions 152 and 153 and the annular space 155 between the small diameter portion 145 and the hole 151 of the spool 141. On the other hand, the blocking portion T1 corresponds to the sliding contact portion t1 between the peripheral wall portion 156 forming the side wall of the annular groove portion 154 in the hole 151 and the large-diameter land portion 144 of the spool 141.
[0010]
On the other hand, when the spool 141 is at the contraction control position SP2 shown in FIG. 5E, the annular groove portions 153 and 154 are communicated with each other via the annular space 155 around the small diameter portion 145 of the spool 141, and the land portion 144 is The right side of the hole 151 is closed, and the land part 143 closes the hole 151 between the annular groove part 152 and the annular groove part 153. In this case, the communication path R2 shown in FIG. 5C corresponds to the annular groove 153 and 154 and the annular space 155 between the small diameter portion 145 of the spool 141 and the hole 151. On the other hand, the blocking portion T <b> 2 corresponds to the sliding contact portion t <b> 2 between the peripheral wall portion 157 that forms the side wall of the annular groove portion 152 of the hole 151 and the large-diameter land portion 143 of the spool 141.
[0011]
In the spool valve 140 as described above, although a temporary operation can be performed, since a minimum time is required for switching the positions SP1 and SP2 of the spool 141, it is difficult to avoid a certain time lag. Further, there is a possibility that the position of the spool 141 is unstable and the predetermined switching cannot be performed.
[0012]
Further, in the spool valve 140, the large-diameter land portions 143 and 144 of the spool 141 should be in sliding contact with the hole 151 of the valve box 150 to cut off the sliding contact portions t1 and t2, thereby forming blocking portions T1 and T2. Since a minimum gap is required between the large-diameter land portions 143 and 144 of the spool 141 and the hole 151 of the valve box 150 in order to allow the sliding of the 141, the leakage of pressure oil at the sliding contact portions t1 and t2 Is likely to occur. If pressure oil leaks at the sliding contact portion t1, that is, the blocking portion T1, the check valve 130 and the pilot operated check valve 120 may be prevented from being opened, and the path indicated by the broken line m1 in FIG. If there is leakage of pressure oil at the sliding contact portion t2, that is, the blocking portion T2, a path indicated by m2 in FIG. 5C is formed, and the check valve 130 may be opened by mistake. In either case, the predetermined operation of the speed increasing valve 110 is hindered. Such leakage is likely to increase due to wear due to long-term use. Further, the spool valve 140 is vulnerable to foreign matters such as dust, and further, high dimensional accuracy is required, and it is difficult to avoid an increase in cost.
[0013]
On the other hand, it has been proposed to provide a speed increasing valve even in a large hydraulic equipment such as a hydraulic excavator or a hydraulic crusher that controls the opening and closing of the jaw by controlling the expansion and contraction of the hydraulic cylinder device by the counter balance valve (Patent Document). 1 and Patent Document 2).
[0014]
  As shown in FIGS. 6A to 6C, the speed increasing valve device 210 is connected to the head side port L1 and the rod side port L2 of the double acting hydraulic cylinder 101 at the outlet ports V1 and V2. The The hydraulic pressure source side port or inlet ports U1 and U2 of the speed increasing valve device 210 are connected to a hydraulic pressure source (not shown) via a switching valve (not shown). One inlet port U1 of the speed increasing valve device 210 and the head side outlet port V1 are directly connected by a pipe line 211. Between the other inlet port U2 and the rod side outlet port V2, there is provided a check valve 240 that allows inflow of pressure oil from the inlet port U2 to the rod side outlet port V2, and the load side port or outlet port Between V1 and V2, when the oil pressure at the inlet port U2 is low and the oil pressure at the outlet port V1 is not high, the flow of pressure oil from the rod-side outlet port V2 to the head-side outlet port V1 can be allowed.RuAn pilot operation check valve 230 is provided. Further, when the hydraulic pressure of the head-side outlet port V1 or the hydraulic pressure of the rod-side outlet port V2 exceeds a predetermined level between the inlet port U2 and the rod-side outlet port V2, the speed increasing device 210 further includes the inlet port U2 and the rod-side outlet. The counter balance valve 220 communicates with the port V2. The counter balance valve 220 includes a check valve that allows the hydraulic pressure to be released.
[0015]
  By operating a switching valve (not shown) on the hydraulic source side, the inlet port U1 is connected to a hydraulic pump (not shown) and the inlet port U2 is connected to an oil reservoir (not shown) and the load on the cylinder 101 6 is small, the pressure oil flows into the head-side oil chamber 102 via the head-side port L1 and discharges the oil in the rod-side oil chamber 103, as shown in FIG. Since the inlet port U2 communicates with the oil reservoir, no pilot pressure is applied to the pilot check valve 230, so that the oil flowing out from the rod side oil chamber 103 of the cylinder 101 is, PaThe pilot check valve 230 is opened to enter the head side oil chamber 102 from the outlet port V1. On the other hand, when the load is small, the pressure in the head-side oil chamber 102 is relatively low, so that the counter balance valve 220 is maintained at the closed position CV1. Accordingly, since the oil flowing out from the rod side oil chamber 103 enters the head side oil chamber 102 as the pressure oil is supplied to the head side oil chamber 102, the speed increasing operation is performed so that the rod 104 protrudes at a relatively high speed. .
[0016]
  When the load increases, as shown in FIG. 6B, the pressure of the hydraulic oil in the head side oil chamber 102 increases,, PaThe pilot operation check valve 230 is closed, and on the other hand, the counter balance valve 220 is set to the open position CV2. Accordingly, the port V2 communicates with the port U2 connected to an oil reservoir (not shown), and the oil in the rod side oil chamber 104 flows out through the counter balance valve 220 toward the port U2.
[0017]
  On the other hand, when the inlet port U2 is connected to a hydraulic pump (not shown) and the inlet port U1 is connected to an oil reservoir (not shown) by operating a switching valve (not shown) on the inlet side, FIG. As shown in (c), PaThe pilot operation check valve 230 is closed by the pilot pressure applied to the port U2, and the counter balance valve 220 is set to the closed position CV1. Therefore, the hydraulic oil passes through the check valve 240 and flows into the rod side oil chamber 103 via the rod side port L2, and pushes the piston to discharge the oil in the head side oil chamber 102. The oil exiting from the head side oil chamber 102 flows to the port U1 through the head side flow path 211 and returns to the oil reservoir (not shown).
[0018]
In the operation of the speed increasing valve 210 as described above, it is indispensable that the operation control of communication / blocking between the flow paths by the counter balance valve 220 is reliably performed.
[0019]
Incidentally, the counter balance valve 220 of the speed increasing circuit 210 schematically shown in FIGS. 6A to 6C actually has a structure as shown in FIG. 6D, for example.
[0020]
6D, the counter balance valve 220 includes a housing or valve box 221 having a valve hole 250, and a piston 260 as a valve body fitted in the valve hole 250 so as to be movable in the B1 and B2 directions. And a spring 222 that exerts a biasing force in the B1 direction on one end 261 of the piston 260, and a pilot pressure input rod 223 that pushes the other end 262 of the piston 260 in the B2 direction. The valve hole 250 includes holes 251, 252, 253 having a precisely constant diameter, a large diameter part 254 a at the tip of the hole 251, a large diameter part 254 b between the holes 251, 252, and the holes 252, 253. And a large-diameter portion 254c therebetween. The large diameter portion 254b is connected to the inlet port UC2 via the flow channel 255, and the large diameter portion 254c is connected to the outlet port VC2 via the flow channel 256. The flow path 256 communicates with the small chamber 225 where the end 223a of the pilot pressure input rod 223 is located via the pilot pressure transmission paths 224a and 224b. The large diameter portion 254c is connected to the port UC2 via a flow path 227 in which a check valve 226 is disposed. The piston 260 includes a rod portion 263 and 264 having an exact diameter that just fits into the hole portions 251 and 253, and a truncated cone-shaped valve body portion having an end portion 252a on the large diameter portion 254c side of the hole portion 252 as a valve seat. A large-diameter portion 266 provided with the H.265, and a small-diameter connecting portion 267a that connects the valve body portion 265 and the rod portion 263. Reference numeral 268 denotes an O-ring.
[0021]
Here, in order for the counter balance valve 220 to function correctly, the diameters of the holes 251, 252, and 253 are exactly the same and the rod 263 so that the balance of the hydraulic pressure applied to the piston 260 can be ensured. , 264 must have a precisely constant diameter according to the hole diameter. In order to satisfy such a requirement, high dimensional accuracy is required, and it is difficult to avoid an increase in cost. Furthermore, the counter balance valve itself is complicated in structure, and thus is prone to failure.
[0022]
Although a speed increasing valve that uses both a spool valve and a counter balance valve in a large hydraulic device has been proposed (Patent Document 3), the proposed speed increasing valve has the above-described two kinds of speed increasing valves. You will have both problems.
[0023]
[Patent Document 1]
Japanese Patent Laid-Open No. 10-266587
[Patent Document 2]
Japanese Patent Laid-Open No. 10-169213
[Patent Document 3]
Japanese Utility Model Publication No. 3-103344
[0024]
The present invention has been made in view of the above points, and an object thereof is to provide a speed increasing valve device that can be reliably operated at low cost.
[0025]
[Means for Solving the Problems]
  In order to achieve the above object, the speed increasing valve device of the present invention is provided with first and second hydraulic pressure source side ports.(U1, U2)WhenConfigured to be connected to the head side oil chamber (14) of the double acting hydraulic cylinder (10)firstThe load side port (V1) and the double side hydraulic cylinder (10) are connected to the rod side oil chamber (13).Second load side port(V2)Booster valve device with(1)Because
  First hydraulic power source side port(U1)And first load side port(V1)The first channel that communicates with(31a)When,
  Second hydraulic power source side port(U2)To second load side port(V2)The second hydraulic power source side port in a direction that allows oil flow to(U2)And second load side port(V2)Second flow path connecting(31e, 31i)The first check valve provided in(60)When,
  First load side port(V1)And second load side port(V2)Third flow path connecting(31g)Second provided inThe paPilot operated check valve(40)And pilot pressuregiveSecond hydraulic power source side port(U2) communicates with the oil sump (21), andFirst flow path(31a)The pressure ofThe pressure is sufficient to extend the piston rod (11) of the double-acting hydraulic cylinder (10) that is actually in an unloaded condition.When second load side port(V2)To first load side port(V1)Allowing the flow of pressure oil to(40)When,
  Second hydraulic power source side port(U2)And second load side port(V2)A fourth channel in parallel with the second channel (31e, 31i)(31d, 31h)3rd pilot operated check valve(50)BecauseTo extend the piston rod (11) of the double-acting hydraulic cylinder (10) in a loaded stateFirst flow path(31a)When the hydraulic pressure is high, the second load side port(V2)From second hydraulic power source side port(U2)Allowing oil flow to(50)When
HaveBooster valve device (1),
  The second pilot operated check valve (40) has a ball (46) that opens and closes the flow path in cooperation with the valve seat (48), and a recess (45g) that holds the ball (46) movably. A valve body structure including a piston (45) fitted into a cylinder hole (43) via a seal ring (49), and a spring (47) biasing the piston (45) toward the one end side In a range in which the peripheral wall portion (45j) of the opening of the recess (45g) can prevent the ball (46) from being removed from the recess (45g), the piston (45) is directed away from the valve seat (48). Consists of a ball valve that is displaceable
  The other end of the piston (45) is configured to apply the pilot pressure,
  The one end side of the piston (45) has a small diameter portion (45b), and communicates with the first flow path (31a) across a portion (43b) of the cylinder hole (43) where the small diameter portion (45b) is located. The downstream flow path (31b) is formed.
[0026]
  In the speed increasing valve device of the present invention, the "first load side port"(V1)And second load side port(V2)Third flow path connecting(31g)Second provided inThe paPilot operated check valve(40)Because, PaIlot pressuregiveSecond hydraulic power source side port(U2) communicates with the oil sump (21), andFirst flow path(31a)The pressure ofThe pressure is sufficient to extend the piston rod (11) of the double-acting hydraulic cylinder (10) that is actually in an unloaded condition.When second load side port(V2)To first load side port(V1)Allowing the flow of pressure oil to(40)”Is provided so that the first load side port in a state where the load is small by connecting the head side oil chamber and the rod side oil chamber of the hydraulic cylinder to the first and second load side ports respectively. When hydraulic oil is introduced into the head side oil chamber and the rod of the hydraulic cylinder is extended, the oil discharged from the rod side oil chamber of the hydraulic cylinderThe paSince it can be made to flow into the head side oil chamber via the pilot operation check valve, the extension speed of the rod of the hydraulic cylinder can be increased.
[0027]
  In the speed increasing valve device of the present invention, the second valveThe paIn addition to the pilot check valve, the second hydraulic pressure source port(U2)And second load side port(V2)Between the second flow path(31e, 31i)4th flow path in parallel with(31d, 31h)3rd pilot operated check valve(50)BecauseTo extend the piston rod (11) of the double-acting hydraulic cylinder (10) in a loaded stateFirst flow path(31a)When the hydraulic pressure is high, the second load side port(V2)From second hydraulic power source side port(U2)Allowing oil flow to(50)When the work by the hydraulic cylinder is started and the load increases and the hydraulic pressure in the head side oil chamber increases,The paThe pilot check valve is closed to stop the supply of accelerating oil from the rod side oil chamber to the head side oil chamber and the third pilot check valve is opened to allow the hydraulic oil in the rod side oil chamber to flow. It returns to the oil sump through the third pilot operated check valve, and the rod is extended at a low speed under a high load.
[0028]
  Further, in the speed increasing valve device of the present invention, “the first hydraulic power source side port”(U1)And first load side port(V1)The first channel that communicates with(31a)And the second hydraulic source side port(U2)To second load side port(V2)The second hydraulic power source side port in a direction that allows oil flow to(U2)And second load side port(V2)Second flow path connecting(31e, 31i)The first check valve provided in(60When the rod of the hydraulic cylinder is contracted, the first check valve is connected by connecting the second inlet port of the speed increasing valve to the hydraulic pump and connecting the second inlet port to the oil reservoir. The hydraulic oil is supplied from the second hydraulic power source side port to the second load side port, and the hydraulic oil is introduced into the rod side oil chamber of the hydraulic cylinder to contract the rod. At this time, the secondThe paThe pilot check valve is subject to reverse pilot pressure.The paThe pilot check valve can be kept closed.
[0029]
The speed increasing valve device of the present invention can be formed by the first check valve and the second and third pilot operated check valves although the above operation can be performed. Since it is not necessary to use a counter balance valve, it is relatively easy to satisfy the requirements for dimensional accuracy, and the cost can be minimized.
[0030]
In the speed increasing valve device of the present invention, the first, second and third check valves are typically ball valves. Therefore, it is relatively easy to satisfy the requirements for dimensional accuracy, and the cost can be minimized. However, if desired, at least one of the check valves, ie one (ie, the first, second or third check valve) or two (ie, the first and second check valves). Valves, or second and third check valves, or third and first check valves) or three (first, second and third check valves) are other types of check valves such as poppet valves. It may be a stop valve.
[0031]
In the speed increasing valve device of the present invention, when the check valve is a ball valve, the ball valve typically has a ball that opens and closes the flow path in cooperation with the valve seat, and a recess that movably holds the ball. In a range in which the peripheral wall portion of the opening of the recess can prohibit the detachment of the ball from the recess, including a valve body structure including a piston provided at one end and a spring that biases the piston toward the one end. The piston can be displaced away from the valve seat. In this case, there is no possibility that the ball is detached from the concave portion at one end of the piston even though the ball is movable with respect to the piston. In addition, since the ball is movable with respect to the piston and only held in the recess of the piston, the sphericity of the ball is ensured as long as the outer diameter of the piston and the inner diameter of the cylinder can satisfy the predetermined dimensional accuracy. By simply opening and closing the flow path between the ball and the valve seat, requirements regarding the shape and size of the inner periphery of the cylinder hole, the outer periphery of the piston, and the inner periphery of the recess can be minimized. That is, for example, by making the inner diameter of the concave portion of the piston slightly larger than the diameter of the ball, the coaxiality may not be satisfied with high accuracy. The manufacturing cost can be minimized.
[0032]
  In addition, the structure of such a check valve is particularly, PaAlthough suitable for the pilot check valve, other check valves have similar advantages. Therefore, this check valve structure is useful not only as a component of the speed increasing valve device but also as a single unit. In that case, the check valve incorporated in an independent or single check valve or any other hydraulic circuit is a check valve device in the form of a ball valve, in which the ball valve cooperates with the valve seat. A valve body structure including a ball that opens and closes the flow path, a piston that includes a recess that movably holds the ball at one end, and a spring that biases the piston toward the one end, and a peripheral wall portion of the opening of the recess The piston can be formed by a check valve device that is displaceable in a direction away from the valve seat within a range in which separation of the ball from the concave portion can be prohibited.
[0033]
  PaWhen this ball valve structure is applied to the pilot check valve, typically, the one end side of the piston has a small diameter portion, and the downstream flow path crosses the portion of the cylinder hole where the small diameter portion is located. It is formed. In this case, when the pressure of the hydraulic oil in the downstream flow path becomes high, the piston moves in a direction away from the ball against the spring force, but the ball is brought into contact with the valve seat by the pressure of the hydraulic oil. It is done.
[0034]
  In the speed-increasing valve device of the present invention, typically, the housings or valve boxes of the first, second and third check valves are formed as one integral block. The block may be a single molded body or a plurality of blocks integrally assembled. However, if desired, a separate check valve(60)Pilot operated check valve(50)AndBipaPilot operated check valve(40)May be connected by a pipeline.
[0035]
Further, in the speed increasing valve device of the present invention, instead of the entirety of the first, second, third and fourth flow paths being incorporated into one valve box block, a part of the flow path is, for example, the first The entire flow path and a part of the third flow path may be formed by pipes or pipes provided separately from the valve box block. In this case, the first hydraulic power source side port and the first load side port are formed in separate piping from the valve box block.
[0036]
In the speed increasing valve device of the present invention, the first load side port is connected to the head side port of the hydraulic cylinder, and the second load side port is connected to the rod side port of the double acting hydraulic cylinder. In the speed increasing valve device of the present invention, the first and second hydraulic source side ports are connected to the hydraulic source and the oil reservoir via the switching valve.
[0037]
DETAILED DESCRIPTION OF THE INVENTION
Next, a preferred embodiment of the present invention will be described based on a preferred example shown in the accompanying drawings.
[0038]
【Example】
1 to 4 show a hydraulically driven bending apparatus 2 using a speed increasing valve apparatus 1 according to a preferred embodiment of the present invention. As can be seen from FIG. 1 in which a hydraulic circuit is schematically shown, the hydraulic drive bending device 2 includes a hydraulic cylinder device 10, a bending tool 3 attached to the protruding end of the piston rod 11 of the hydraulic cylinder device 10, The speed increasing valve device 1 is connected to a hydraulic pressure source 20 including an oil reservoir 21 and a hydraulic pump 22 via a switching valve 23.
[0039]
The hydraulic cylinder device 10 is a double-acting hydraulic cylinder, and includes a cylinder body 13 having a cylinder hole 12 and a cylinder hole 12 that is slidably inserted in the D1 and D2 directions. The hydraulic piston 16 defined in the chamber 14 and the rod side oil chamber 15, and the piston rod 11 that penetrates the rod side oil chamber 15 from one end fixed to the piston 16 and protrudes through the end wall of the cylinder body 13. Including. The head side oil chamber 14 is formed with a head side port L1 that allows the hydraulic oil to enter and exit the oil chamber 14, and the rod side oil chamber 15 has the rod side that allows the hydraulic oil to enter and exit the oil chamber 15. A port L2 is formed.
[0040]
When the switching valve 23 has a pair of hydraulic source side ports Xi1, Xi2 and a pair of load side ports Xo1, Xo2, and the switching valve main body 24 is in the first position X1, (a) in FIG. As shown in (b), when the hydraulic pressure source side port Xi1 is connected to the load side port Xo1 and the hydraulic pressure source side port Xi2 is connected to the load side port Xo2 and is in the third position X3, FIG. (C), the hydraulic pressure source side port Xi1 is connected to the load side port Xo2 and the hydraulic pressure source side port Xi2 is connected to the load side port Xo1. When the switching valve body 24 is in the second position (not shown), the connection between the hydraulic pressure source side ports Xi1, Xi2 and the load side ports Xo1, Xo2 is disconnected. The position control of the switching valve 23 is performed, for example, by energization control to the electromagnetic coil 25.
[0041]
  The speed increasing valve device 1 includes a housing 30 having first and second hydraulic power source side port portions U1, U2 and first and second load side port portions V1, V2, and a first formed in the housing 30. oneThe paThe pilot control check valve portion 40, the second pilot operation check valve portion 50, and the third check valve portion 60 are provided.
[0042]
  Referring to FIG. 1, the housing 30 includes an oil passage 31a that connects the first hydraulic pressure source side port U1 and the first load side port V1, an oil passage 31a, and a first passage.The paThe speed increasing branch oil passage 31b connecting the downstream port 41 of the pilot check valve portion 40, the oil passage 31c extending from the second hydraulic power source side port U2, and the oil passage 31c for the second pilot operation An oil passage 31d connected to the upstream port 51 of the check valve 50, an oil passage 31e connecting the oil passage 31c to the upstream port 61 of the third check valve 60, and the second load side port V2 extend. The oil passage 31f and the oil passage 31fThe paA speed increasing branch oil passage 31g connected to the upstream port 42 of the pilot operation check valve 40, an oil passage 31h connecting the oil passage 31f to the downstream port 52 of the second pilot operation check valve 50, and an oil passage 31f is connected to the downstream port 62 of the third check valve 60, and the second hydraulic pressure source side port U2 or the hydraulic pressure of the oil passage 31f is set to the first hydraulic pressure.The paThe hydraulic pressure of the first hydraulic pressure transmission path 32a and the first load side port V1 to the first hydraulic path 31a transmitted to the upstream side of the pilot operation check valve 40 is transmitted to the upstream side of the second pilot operation check valve 50. And a second hydraulic transmission path 32b. Here, for convenience of explanation, the oil passages in FIG. 1 are denoted by reference numerals, but the oil passages 31a, 31b are in communication with each other, so that no distinction is required, and the oil passages 31c, 31d, 31e are mutually connected. No distinction is required because they are in communication, and no distinction is required because the oil passages 31f, 31g, 31h, 31i communicate with each other. Therefore, in the structure explanatory diagrams of FIGS. 2 and 3 to be described in detail later, the connection relationship of the oil passages that do not need to be distinguished may be different.
[0043]
  firstThe paAs shown in FIG. 4 in an enlarged manner, the pilot check valve 40 includes a housing part or a valve box part 44 in which a cylinder hole 43 is formed, and a cylinder hole that can move in the E1 and E2 directions within the cylinder hole 43. 43, a piston or plunger 45 fitted and inserted into the valve 43, a ball 46 as a valve body, and a compression spring 47 that biases the piston 45 in the E1 direction.
[0044]
The cylinder hole 43 includes a cylindrical cylinder hole main body portion 43a that extends across the oil passage 31a at the intersection portion 43b, and a truncated cone portion 43c formed on one end side of the main body portion 43a. There is one connected to 31g and a disk-like recess 43d formed concentrically on the other end side of the main body 43a and connected to the pilot pressure transmission path 32a at the center.
[0045]
The cylinder hole 43 is substantially concentric with the oil passage 31g, and an intersection line 48 between the peripheral wall of the oil passage 31g and the peripheral wall portion of the truncated cone portion 43c functions as a circular valve seat. The disc-shaped recess 43d is also substantially concentric with the adjacent portion 32a1 of the pilot pressure transmission path 32a, and the bottom wall 43e of the disc-shaped recess 43d serves as a seat for the compression spring 47.
[0046]
The piston 45 includes a cylindrical piston main body 45a, a small diameter portion 45b formed on one end side of the main body 45, and a truncated cone portion 45c that connects the main body 45a and the small diameter 45b. Therefore, the oil passage 31 a that crosses the cylinder hole 43 is always connected via the annular space 43 h around the small diameter portion 45 b of the piston 45. The main body 45a is provided with a mesh hole 45d opened at the end face on the other end side, and most of the compression spring 47 is received in the hole 45d. The main body 45a further includes an annular groove 45e on the outer periphery, and an O-ring 49 serving as a seal ring is fitted in the annular groove 45e.
[0047]
The small-diameter portion 45b is formed with a cylindrical hole 45g that opens at the end face 45f and can receive the ball 46. The bottom wall portion 45h of the cylindrical hole 45g has a conical shape so that the ball 46 can be received deeply. . However, the apex angle of the cone is sufficiently large so that high concentricity is not required.
[0048]
The outer diameter of the main body 45a of the piston 45 is substantially equal to the inner diameter of the main body 43a of the cylinder hole 43, but is slightly smaller than the inner diameter. Since the main body 45a of the piston 45 and the main body 43a of the cylinder hole 43 are sealed by an O-ring 49, the shape accuracy of the piston main body 45a and the outer diameter may be relatively low. The dimensional accuracy of the shape and outer diameter of the main body 43a of 43 may be relatively low.
[0049]
The inner diameter of the cylindrical ball receiving hole 45g of the small diameter portion 45b of the piston 45 is slightly larger than the outer shape of the ball 46, and the shape and the dimensional accuracy of the inner diameter may be relatively low. The length of the piston 45, that is, the length between the end 45i of the large diameter main body 45a of the piston 45 and the tip of the small diameter 45b of the piston 45 (tip of the cylindrical wall 45j forming the peripheral wall of the recess 45g) The tip H of the small-diameter portion 45b when the end portion 45i of the large-diameter main body portion 45a of the piston 45 comes into contact with the end wall 43f of the cylinder hole 43 as shown in FIGS. The gap G between the portion 45f and the peripheral wall 43g of the frustoconical portion 43c of the cylinder hole 43 is smaller than the diameter of the ball 46, and the ball 46 can be prohibited from detaching from the recess 45g via the gap G. It has become a length.
[0050]
  Therefore, thisThe paIn the pilot operation check valve 40, when the oil pressure in the oil passage 31g and the oil pressure in the oil passage 31a (31b) are low and the pilot pressure in the pilot pressure transmission passage 32a is low, the compression spring 47 moves the back side of the piston 45 to E1. Since the piston 45 pushes the ball 46 positioned in the recess 45g in the E1 direction with the conical bottom 45h, the ball 46 is pressed against the valve seat 48, and the oil passage 31g and the oil passages 31a to 31b The gap is kept in a disconnected state. At this time, since the inner diameter of the recess 45g is slightly larger than the outer diameter of the ball 46, the ball 46 is just pressed and brought into contact with the circular valve seat 48 while being accommodated in the recess 45g. Thus, a slight deviation in size and shape can be adjusted by a positional deviation of the ball 46 in the recess 45g. It should be noted that the apex angle of the conical surface 45h is sufficiently large (for example, the angle when viewed in a cross section is about 120 degrees or more) so that a certain degree of concentricity can be allowed. On the other hand, when the pilot pressure applied from the pilot pressure transmission path 32a to the back side of the piston 45 is low and the hydraulic pressure applied to the oil path 31a (31b) is not high, the hydraulic pressure applied to the oil path 31g increases. The piston 45 supporting the valve 46 is pushed in the E2 direction against the spring force of the spring 47, and a gap G is generated between the ball 46 and the valve seat 48, so that the pressure oil flows from the oil passage 31g to the oil passages 31a to 31b. Flowing. At this time, even if a situation occurs in which the piston 45 is displaced in the E1 direction larger than the ball 46, the tip of the peripheral wall 45j of the recess 45g of the piston 45 when the piston 45 is displaced in the E2 direction to the maximum. Since the gap G generated between the portion 45f and the cylinder hole 43 is smaller than the diameter of the ball 46, there is no possibility that the ball 46 is detached from the inside of the recess 45g to the outside of the recess 45g. Further, when the oil pressure in the oil passage 31a is less than or equal to the oil pressure in the oil passage 31g, the pilot pressure applied from the pilot pressure transmission passage 32a to the back side of the piston 45 increases and becomes equal to or more than the oil pressure in the oil passage 31g. Then, the piston 45 is pushed in the E1 direction by the pilot pressure, the ball 46 is pushed against the valve seat 48 by the piston 45, and the flow path between the oil passage 31g and the oil passages 31a to 31b is closed. In addition, even when the pressure in the pilot pressure transmission path 32g is low, if the oil pressure in the oil path 31a (31b) is high, the ball 46 is pressed against the valve seat 48 in the E1 direction by the oil pressure. In this case, a force in the E2 direction is applied to the piston 45, and the piston 45 is biased in the E2 direction until the end portion 45i abuts against the end wall or the end surface 43f of the cylinder hole 43, as shown in FIG. In FIG. 4 (c), there is a gap between the ball 46 and the valve seat 48, or between the end 45i of the piston 45 and the end wall or end face 43f of the cylinder hole 43 for the sake of clarity. Are shown as if they remain, but there are no gaps in these parts). Even in this case, since the gap G is smaller than the diameter of the ball 46, there is no fear of the ball 46 being detached.
[0051]
  For example, in FIG. 4A, as indicated by an imaginary line 33a and an imaginary line 33b, the housing 30 is composed of two or more blocks, and these blocks are assembled to form the housing 30. If you want to keepThe paWhen assembling the pilot check valve 40, the ball 46 is inserted into the cylinder hole 43, and then the piston 45 fitted with the O-ring 49 is inserted into the cylinder hole 43. The ball 46 is fitted. Finally, the compression spring 47 is fitted into the back side recess 45d of the piston 45, and the housing block is assembled along the imaginary line 33a or the imaginary line 33b., PaThe pilot operation check valve 40 is easily formed. When assembling, the inner diameter of the recess 45g of the piston 45 is made slightly larger than the diameter of the ball 46, and the outer diameter of the piston 45 is made slightly smaller than the inner diameter of the cylinder hole 43. Even if there is a misalignment, the misalignment can be absorbed, so that the requirement for the dimensional accuracy of each part is reduced, the manufacturing can be facilitated, and the cost can be minimized. In addition, since the structure is simple, manufacturing is easy and the cost can be minimized, and reliable operation is easily realized.
[0052]
  As can be seen from FIGS. 2 and 3, the pilot operated check valve 50 has a pilot pressure applying mechanism 70 except that it has a pilot pressure applying mechanism 70., PaIt has substantially the same structure as the pilot operation check valve 40. That is, the pilot operated check valve 50 is a piston or plunger 55 having the same structure and shape as the piston or plunger 45 except that a cylinder hole 53 similar to the cylinder hole 43 and an O ring such as an O ring 49 are lacking. A ball 56 having the same shape as the ball 46, a compression spring 57 similar to the spring 47, and the like except for a point stronger than the spring 47 are provided. Therefore, the piston 55 has a cylindrical large-diameter portion 55a, a cylindrical small-diameter portion 55b, and a truncated cone-shaped connecting portion 55c. The cylindrical small-diameter portion 55b has an inner diameter slightly larger than the diameter of the ball 56. A cylindrical hole 55g opened at the end 55f is formed. The ball 56 is loosely fitted in the cylindrical hole 55g (inside the peripheral wall 55j) with a part of the ball 56 protruding from the cylindrical hole 55g. A valve seat portion 58 similar to the valve seat portion 48 is formed in the housing portion or the valve box portion 54 in which the cylinder hole 53 is formed.
[0053]
The pilot pressure application mechanism 70 of the pilot operation check valve 50 includes a piston structure 72 disposed in a through hole 71 formed between the oil passage 31a and the oil passage 31d. The through hole 71 includes a large diameter hole portion 73 and a small diameter hole portion 74 in the illustrated example. The piston mechanism 72 includes a large-diameter piston portion 75 that is slidably fitted in the large-diameter hole portion 73 in the J1 and J2 directions, and a large-diameter hole portion 73, a small-diameter hole portion 74, and an oil from one end of the piston portion 75. And a push rod portion 76 extending through the passage 31d. When the large-diameter piston portion 75 is positioned at the end of the large-diameter hole portion 73 in the J1 direction, the tip portion 78 of the rod portion 76 passes through a small gap (not shown) because the ball 56 of the pilot check valve 50 is small. (For example, (a) and (b) in FIG. 2). An O-ring 77 is fitted to the piston portion 75.
[0054]
Accordingly, when the oil pressure of the oil passage 31a serving as the pilot pressure is high, the piston structure 72 is pushed in the J2 direction, and the ball 56 is moved in the J2 direction by the tip 78 of the rod 76 against the force of the spring 57 in the J1 direction. The oil passage 31h and the oil passage 31d are communicated with each other through an annular space 53h around the small diameter portion 55b (see (a) of FIG. 3).
[0055]
As can be seen from FIGS. 2 and 3, the check valve 60 has substantially the same structure as the pilot operated check valve 50 except that the pilot pressure application mechanism is lacking. That is, the check valve 60 includes a cylinder hole 63 similar to the cylinder hole 53, a piston or plunger 65 having the same structure and shape as the piston or plunger 55, a ball 66 similar to the ball 56, and a spring force from the spring 57. A compression spring 67 similar to the spring 57 is provided except that it is small (and smaller than the spring 47). The piston 65 slidable in the K1 and K2 directions in the cylinder hole 63 has a cylindrical large diameter portion 65a, a cylindrical small diameter portion 65b, and a truncated cone-shaped connection portion 65c. The cylindrical small diameter portion 65b includes a ball A cylindrical hole 65g having an inner diameter slightly larger than the diameter of 66 and opening at the end 65f is formed. The ball 66 is loosely fitted into the cylindrical hole 65g (cylindrical peripheral wall 65j) with a part of the ball 66 protruding from the cylindrical hole 65g. A valve seat portion 68 similar to the valve seat portion 58 is formed in the housing portion or the valve box portion 64 in which the cylinder hole 63 is formed.
[0056]
Therefore, when the oil pressure in the oil passage 31e is low, the ball 66 is pressed against the valve seat 68 by the weak spring force in the K1 direction of the spring 67, and the oil passage 31e and the oil passages 31i and 31h are blocked (see FIG. 2 (b), etc.) When the oil pressure of the oil passage 31e is high, the ball 66 is pushed in the K2 direction against the weak spring force of the spring 67 in the K1 direction, and the oil passage from the oil passage 31e through the annular space 65h. The flow of pressure oil to 31i thru | or 31h is permitted (refer FIG.3 (b)).
[0057]
The operation of the hydraulic drive bending device 2 having the speed increasing valve device 1 configured as described above will be described with reference to FIGS. Here, it is assumed that the bending object or the bent object is a bar M such as a square bar, a round bar, or a long member having an L-shaped cross section as shown in FIG. The bar M is placed on the base so as to be supported on the back surface by the supports N1 and N2 supported on the base (not shown) for bending. On the other hand, the main body 13 of the hydraulic cylinder device 10 is arranged and fixed so that the tool 3 faces the bent bar M on the base. Here, the interval Q between the tip 3a of the tool 3 and the bent bar M is small for convenience of illustration in FIG. 1 (a), but is actually relatively large. The stroke Q in the D1 direction of the bending tool 3 until the bending tool 3 comes into contact with the workpiece M can vary depending on the workpiece M.
[0058]
  Initially, the hydraulic pump 22 is in an inoperative state, and the speed increasing valve device 1, PaThe pilot operation check valve 40, the pilot operation check valve 50 and the check valve 60 are closed by respective springs 47, 57 and 67 ((a) of FIG. 2).
[0059]
  The hydraulic pump 22 is actuated (after setting the switching valve 23 to the state X1 if necessary). As shown in FIG. 1 (a), hydraulic oil from the pump 22 passes through the switching valve 24, enters the port U1 of the speed increasing valve device 1, passes through the oil passage 31a, and passes through the head side of the cylinder device 10. The oil chamber 14 is entered, the piston 16 of the cylinder device 10 is pushed in the D1 direction, the tool 3 is moved in the D1 direction via the piston rod 11, and is brought close to the bent bar M. On the other hand, the oil discharged from the rod side oil chamber 15 due to the displacement of the piston 16 in the D1 direction is the oil passage 31f of the speed increasing valve device 1 as shown in FIG. 1 (a) and FIG. 2 (b). , Through 31g, PaThe pilot operation check valve 40 opens in the E2 direction against the force of the spring 47, enters the oil passage 31a through the oil passage 31b ((a) in FIG. 1), and enters the head-side oil chamber 14 of the cylinder device 10. be introduced. PaDue to such oil flow through the pilot operation check valve 40, the flow rate of the hydraulic oil entering the head side oil chamber 14 is higher than the flow rate of the hydraulic oil from the pump 22, so that the protruding speed of the tool 3 in the D1 direction is increased. Can be enhanced.
[0060]
On the other hand, although the hydraulic pressure from the hydraulic pump 22 is applied to the pilot check valve 50, the piston 16 moves in the D1 direction in a state where no load is applied to the tool 3 (actually no load or a small load on the hydraulic cylinder 10). Since the oil pressure in the oil passage 31a is relatively low because the oil is moved, the force applied in the J2 direction to the piston 75 of the pilot pressure operating mechanism 70 in FIG. The pilot operation valve 50 pressed against the valve seat 58 is kept closed. In addition, since the check valve 60 is only subjected to the hydraulic pressure in the closing direction, the valve 60 is kept closed. As a result, the speed increasing valve device 1 takes a state as shown in FIG.
[0061]
  When the tool 3 moves by a distance Q in the D1 direction movement, the tip 3a of the tool 3 comes into contact with the bent bar M, and thereafter, the tool 3 exerts a bending force F on the bent bar M. However, it is moved in the direction D1. That is, when the bending of the bent bar M by the tool 3 is started, the load in the D2 direction on the cylinder device 10 is rapidly increased, so that the oil pressure of the oil passage 31a is increased. As a result, a pressure difference is generated between the oil passage 31a (31b) and the oil passage 31g, as shown in FIG., PaIn the pilot operation check valve 40, the ball 46 is pressed against the valve seat 48 to close the oil passage between the oil passage 31a (31b) and the oil passage 31g. In this state,, PaSince the piston 45 of the pilot check valve 40 is pushed in the E2 direction by the oil pressure of the oil passage 31a (31b), the ball 46 opens the hole 45g of the piston 45 as shown in FIG. The position which protrudes greatly from the position is taken (corresponding to (c) of FIG. 4). Accordingly, the hydraulic oil presses the ball 46 against the valve seat 48 in the E1 direction in the oil passage 31a in FIG. 3A (in the oil passage 31b connected to the oil passage 31a in FIG. 1B), and With the piston 45 pressed against the spring 47 in the E2 direction, it flows through the oil passage 31a.
[0062]
On the other hand, when the hydraulic pressure applied from the oil passage 31a to the pilot operation check valve 50 is increased due to the influence of the bending load, the force applied to the piston 75 of the pilot pressure operating mechanism 70 in the J2 direction increases. As shown, the piston 75 pushes the ball 56 in the J2 direction against the strong spring force of the spring 57 to release the ball 56 from the valve seat 58, so that the pilot operated check valve 50 is set to the open state.
[0063]
  Therefore, the hydraulic oil discharged from the rod side oil chamber 15 of the cylinder device 10 is, PaInstead of the pilot operation check valve 40, the pilot operation check valve 50 is passed along the oil passages 31f, 31h, 31d, 31c. As a result, the speed increasing operation by the speed increasing valve device 1 is stopped, and the tool 3 of the cylinder device 10 is protruded in the direction D1 so as to bend the bar M at a lower speed than when no load is applied.
[0064]
In addition, since the check valve 60 is only subjected to the hydraulic pressure in the closing direction, the valve 60 is kept closed. As a result, the speed increasing valve device 1 takes a closed state as shown in FIG.
[0065]
Until the bending process (bending operation) on the bar M is completed, the tool 3 is projected in the direction D1, and the state shown in FIG.
[0066]
When the bending process is completed, the switching valve 23 is switched from the state X1 shown in FIG. 1B to the state X3 shown in FIG. As a result, the pressure oil from the hydraulic pump 22 is introduced into the port U2 of the speed increasing valve device 1, and the oil from the port U1 is returned to the oil reservoir 21.
[0067]
  In this state, the hydraulic oil flows into the oil passage 31c, so that the pressure transmission passage 32a is used.THydraulic pressure is applied to the back side of the piston 45 of the pilot check valve 40, the piston 45 is pushed in the direction E1, and the ball 46 is deeply fitted into the recess 41g of the small diameter portion 45b of the piston 45 and hits the bottom wall 45h. It is pushed in the E1 direction by 45h and pushed against the valve seat 48., PaThe pilot operation check valve 40 is kept closed.
[0068]
On the other hand, the hydraulic oil flowing through the oil passages 31c and 31e pushes the ball 66 and the piston 65 biased in the K1 direction by the weak spring 67 in the K2 direction, separates the ball 66 from the valve seat 68, and flows into the flow passage 31i. In addition, once the flow of oil from the flow path 31e to the flow path 31i is started, the valve 60 is kept open by the dynamic pressure accompanying the flow. Here, even if the oil enters the recess 64d with the spring 67 through the narrow gap between the piston 65 and the cylinder hole 63, the static pressure of the oil applied to the left and right of the piston 65 is balanced. As long as the dynamic pressure accompanying the flow exceeds the spring force of the spring 67 (for example, when the spring force of the spring 67 is about 10 kPa in consideration of the cross-sectional area of the piston 65, a flow rate of oil that gives a dynamic pressure of about 50 kPa flows. Note that the strength and flow rate of the spring may be larger or smaller as long as the relative magnitude relationship can be maintained), and the valve 60 can be kept open.
[0069]
Further, since the oil passage 31a is connected to the oil reservoir 22 and the pressure is lowered, the pressure in the J2 direction against the piston 75 of the pilot pressure operating mechanism 70 disappears, and the ball 56 moves to the valve seat 58 in the J1 direction by the spring force of the spring 57. The pilot-operated check valve 50 is closed by pressing (the piston 55 of the pilot-operated check valve 50 also balances the left and right forces due to the left and right hydraulic pressures, and can be ignored, as in the case of the check valve 60. Is). Since the spring force of the spring 57 of the pilot operated check valve 50 is much larger than the spring force of the spring 67 of the check valve 60, the valve 50 is set and maintained in the closed state.
[0070]
Therefore, as shown in FIG. 1C and FIG. 3B, the hydraulic oil from the hydraulic pump 21 is introduced into the rod-side oil chamber 15 of the cylinder device 10 through the check valve 60. The piston 16 of the cylinder device 10 is pushed back in the direction D2, and the rod 11 and the tool 3 are moved back in the direction D2. The hydraulic oil in the head side oil chamber 14 is returned to the oil reservoir 21 through the oil passage 31a.
[0071]
As described above, one bending operation is completed.
[0072]
In FIGS. 2 and 3 described above, an example in which the entire speed increasing valve device 1 is formed in one valve box block or cylinder block 30 has been described, but is shown by an imaginary line 1B in FIG. With the boundary line as a boundary, one portion 1Ba may be incorporated into the cylinder block, and the portion 1Bb including the left flow path may be formed by a pipe or pipe provided separately from the cylinder block. In that case, a part of the flow path, for example, the entire flow path 31a forming the first flow path and a part of the flow path 31b forming a part of the third flow path are the valve box block. It is formed by separately provided piping or pipes. In this case, the first hydraulic pressure source side port U1 and the first load side port V1 are formed as pipes or pipes separate from the valve box block.
[0073]
  In the above, the check valve 60 and the pilot operated check valve 50 are used.AlsoAlthough it has been described as having substantially the same structure as the pilot operation check valve 40, if desired, for example, a poppet valve may be used instead of the ball valve.
[Brief description of the drawings]
FIG. 1 schematically shows a bending apparatus provided with a speed increasing valve device according to a preferred embodiment of the present invention, wherein (a) is a schematic explanation of a pre-bending process in a no-load (low-load) state. FIG. 4B is a schematic explanatory diagram of the bending process in a loaded state, and FIG. 5C is a schematic explanatory diagram of the return process of the cylinder device.
2 shows the configuration of the speed increasing valve device of FIG. 1, in which (a) is a cross-sectional explanatory view showing a state before the speed increasing valve device is operated, and (b) is a view (a) of FIG. Cross-sectional explanatory drawing similar to (a) about the speed increasing valve apparatus in the state.
3 shows different operating states of the speed increasing valve device of FIG. 2, in which (a) is the same as (b) of FIG. 2 for the speed increasing valve device in the state of (b) of FIG. An explanatory sectional view, (b) is an explanatory sectional view similar to (a) about the speed increasing valve device in the state of (c) of FIG.
4 is a view of the speed increasing valve device of FIG.ChipaIt is an enlarged view of the pilot check valve, (a) is an enlarged cross-sectional explanatory view when the speed increasing valve device is closed by a spring force or pilot pressure, and (b) is the speed increasing valve device opened. Explanatory cross-sectional explanatory drawing about the state which is, (c) is an enlarged cross-sectional explanatory view of the state where the piston and ball of the speed increasing valve device are separated to the maximum.
FIGS. 5A and 5B show a conventional speed increasing valve device using a spool valve. FIG. 5A is a schematic explanatory view of a pre-bending process in a no-load (low load) state, and FIG. (C) is a schematic explanatory view of the return process of the cylinder device, (d) and (e) are cross-sectional explanatory views regarding the structure of a conventional speed increasing valve device using a spool valve. (E) is a VE-VE line section explanatory view of (d).
6A and 6B show a conventional speed increasing valve device using a counter balance valve. FIG. 6A is a schematic explanatory view of a pre-bending process in a no-load (low load) state, and FIG. 6B is a load state. (C) is a schematic explanatory drawing of the return process of a cylinder apparatus, (d) is sectional explanatory drawing regarding the structure of a counter balance valve among speed-up valve apparatuses.
[Explanation of symbols]
  1 Booster valve device
  2 Bending equipment
  3 Bending tools
10 Hydraulic cylinder device
11 Piston rod
14 Head side oil chamber
15 Rod side oil chamber
16 piston
20 Hydraulic source
21 Oil sump
22 Hydraulic pump
23 Switching valve
40PaPilot operated check valve
50 Pilot operated check valve
60 Check valve
30 Housing
43, 53, 63 Cylinder hole
44, 54, 64 Housing part
45, 55, 65 piston
46, 56, 66 balls
47, 57, 67 Compression spring
48, 58, 68 Valve seat
49 O-ring
31a, 31b, 31c, 31d, 31e, 31f, 31g, 31h, 31i Oil passage
32a, 32b Pilot pressure transmission path
D1, D2, E1, E2, J1, J2, K1, K2 direction
  G gap
  H length
L1 head side port
L2 Rod side port
  Q interval
U1, U2 Hydraulic source side port
V1, V2 Load side port

Claims (6)

The first load side port (V1 ) configured to be connected to the first and second hydraulic power source side ports (U1, U2) and the head side oil chamber (14) of the double acting hydraulic cylinder (10). ) And a second load side port (V2) configured to be connected to the rod side oil chamber (15) of the double acting hydraulic cylinder (10 ) . There,
A first flow path (31a) communicating the first hydraulic pressure source side port (U1) and the first load side port (V1) ;
The second hydraulic source side port (U2) and the second load side port (V2) are arranged in a direction allowing oil flow from the second hydraulic source side port (U2) to the second load side port (V2). A first check valve (60) provided in the second flow path (31e, 31i) connecting
A second pilot operated check valve provided in the third flow path connecting the first load port (V1) and a second load port (V2) (31g) (40 ), The double acting hydraulic cylinder in which the second hydraulic pressure source side port (U2) for applying pilot pressure is communicated with the oil reservoir (21), and the pressure of the first flow path (31a) is practically in an unloaded condition Allowing the flow of pressure oil from the second load side port (V2) to the first load side port (V1) when the pressure is sufficient to extend the piston rod (11) of (10) (40) When,
Provided in the fourth flow path (31d, 31h) in parallel with the second flow path (31e, 31i) between the second hydraulic power source side port (U2) and the second load side port (V2). A third pilot operated check valve (50) , wherein the hydraulic pressure of the first flow path (31a) is set to extend the piston rod (11) of the double-acting hydraulic cylinder (10) in a loaded state. In the speed increasing valve device (1) having, when high, an oil flow (50) from the second load side port (V2) to the second hydraulic pressure source side port (U2) ,
The second pilot operated check valve (40) has a ball (46) that opens and closes the flow path in cooperation with the valve seat (48), and a recess (45g) that holds the ball (46) movably. A valve body structure including a piston (45) fitted into a cylinder hole (43) via a seal ring (49), and a spring (47) biasing the piston (45) toward the one end side In a range in which the peripheral wall portion (45j) of the opening of the recess (45g) can prevent the ball (46) from being removed from the recess (45g), the piston (45) is directed away from the valve seat (48). Consists of a ball valve that is displaceable
The other end of the piston (45) is configured to apply the pilot pressure,
The one end side of the piston (45) has a small diameter portion (45b), and communicates with the first flow path (31a) across the portion (43b) of the cylinder hole (43) where the small diameter portion (45b) is located. A speed increasing valve device in which the downstream flow path (31b) is formed . Speed increasing valve device according to claim 1 first Ichi及 Beauty third check valve is a ball valve. The ball valve constituting the first and third check valves includes a ball that opens and closes the flow path in cooperation with the valve seat, a piston that has a recess at one end for movably holding the ball, and the piston A valve body structure including a spring biased to one end side, and the piston can be displaced in a direction away from the valve seat within a range in which the peripheral wall portion of the opening of the recess can inhibit the detachment of the ball from the recess. The speed increasing valve device according to claim 2.   The speed increasing valve device according to any one of claims 1 to 3, wherein the valve box portions of the first, second and third check valves are formed as one integral block.   The speed increasing valve device according to any one of claims 1 to 4, a head side port connected to a first load side port of the speed increasing valve device, and a rod side port to a second load side port And a double-acting hydraulic cylinder connected to the hydraulic cylinder device.   6. The hydraulic cylinder device according to claim 5, wherein the first and second hydraulic source side ports are connected to the hydraulic source and the oil reservoir via a switching valve.

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