JP3658434B2 - Liquid control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a liquid control apparatus that controls pressure reduction of a pressure liquid introduced into a liquid actuator using a pressure reducing valve, or prevents pressure reduction control.
[0002]
[Prior art]
In general, there is a pressure reducing valve for controlling the pressure liquid to be depressurized or not depressurizing, as shown in Japanese Utility Model Publication No. 4-38088. The applicant of the present application has considered a liquid control apparatus as shown in FIG. 4 to control the pressure of the pressure liquid introduced into the liquid actuator using the pressure reducing valve or not to control the pressure reduction.
[0003]
In the liquid control apparatus shown in FIG. 4, an electromagnetic switching valve 47 is laminated on a pressure reducing valve 46 corresponding to the pressure reducing valve of Japanese Utility Model Publication No. 4-38088, and the electromagnetic switching valve 47 has two load flow paths. Since one load channel A1 is not used in A1 and B1, it is closed and the other one load channel B1 is connected to the single-acting cylinder 1 as a liquid actuator, and the pressure channel is connected to the load channel B1. The supply flow path P1 connected to the pressure source P to be supplied and the discharge flow path R connected to the low pressure side T are provided so as to be able to switch and communicate by an energization / non-energization operation. The pressure reducing valve 46 is a pilot-actuated type, and a pilot solenoid valve 49 and a pilot pressure control valve 50 for connecting and disconnecting the pilot passage 48 by energization / non-energization operation are arranged in series in the pilot passage 48. The pressure liquid flowing through the supply flow path P <b> 1 by the energization / non-energization operation is controlled so as not to be depressurized or set to the set pressure set by the pilot pressure control valve 50.
[0004]
Next, the operation will be described. FIG. 4 shows a clamped state of the workpiece W. The electromagnetic switching valve 47 is not energized, communicates the load flow path B1 to the discharge flow path R and shuts off the supply flow path P1, and the pressure reducing valve 46 is connected to the pilot electromagnetic valve 49. The single-acting cylinder 1 clamps the workpiece W by the force of the spring 1A without shutting off the pilot passage 48 and depressurizing the pressure liquid in the supply passage P1 without being energized.
[0005]
From this state, when the electromagnetic switching valve 47 is energized, the load flow path B1 is switched to the supply flow path P1, the discharge flow path R is shut off, and the pressure liquid in the supply flow path P1 that is not pressure-reduced by the pressure reducing valve 46 is The single-action cylinder 1 flows through the load channel B1 and is introduced into the working chamber 1B of the single-action cylinder 1, and the single-action cylinder 1 resists the force of the spring 1A with the acting force based on the pressure of the pressure liquid introduced into the working chamber 1B. The workpiece W moves in the direction to make the workpiece W unclamped, and the workpiece W is replaced with a new one.
[0006]
In this state, when the pilot solenoid valve 49 of the pressure reducing valve 46 is energized, the pressure liquid in the supply flow path P1 is controlled to be reduced to the set pressure set by the pilot pressure control valve 50 of the pressure reducing valve 46, and the single-acting cylinder 1 is operated. The acting force based on the pressure of the pressure liquid in the chamber 1B is slightly lower than the force of the spring 1A, and the single acting cylinder 1 gradually moves in the left direction in FIG. When the solenoid switching valve 47 is deenergized, the solenoid valve 47 returns to the original position shown in FIG. 4 to switch the load channel B1 to the discharge channel R, and the pressure liquid in the working chamber 1B is discharged from the load channel B1. The single acting cylinder 1 flows through the flow path R and is led out to the low pressure side T, and the new work W is clamped by the force of the spring 1A. Further, the pressure reducing valve 46 returns to the original position shown in FIG. 4 by deenergizing the pilot solenoid valve 49 in preparation for the next unclamping operation.
[0007]
[Problems to be solved by the invention]
However, in the liquid control apparatus shown in FIG. 4, the load flow path B1 is switched and connected to the supply flow path P1 and the discharge flow path R by the energization / non-energization operation of the electromagnetic switching valve 47, and the pilot electromagnetic valve 49 of the pressure reducing valve 46 is connected. Since the pressure liquid in the supply flow path P1 is controlled to be depressurized or not depressurized by the energization / non-energization operation, the energization / non-energization operation of the electromagnetic switching valve 47 and the energization / non-energization operation of the pilot solenoid valve 49 of the pressure reduction valve 46 are performed. And the operation becomes complicated.
[0008]
[Means for Solving the Problems]
The present invention has been made in order to solve the above-described problems, and it is possible to prevent the pressure switch from being controlled to be depressurized or not depressurized by the energization / non-energization operation of the electromagnetic switching valve. Providing a liquid control device that is easy to operate, a supply flow path for supplying pressure liquid, a discharge flow path connected to the low pressure side, a load flow path connected to the liquid actuator, and a pilot liquid in circulation A first flow path that connects the load flow path to the discharge flow path, communicates the pilot flow path to the supply flow path, and connects the load flow path to the supply flow path, and makes the pilot flow path the discharge flow path. An electromagnetic switching valve having a second position communicating with the first position and the second position by an energization / non-energization operation, and a pressure reducing valve disposed in the supply flow path, Storing a spring that sets the secondary pressure of the supply flow path And a pilot branch channel that connects the storage chamber to the primary side of the supply channel. The throttle branch channel is provided with a throttle, and the throttle is disposed between the throttle and the storage chamber. A pilot flow path is connected, and a pilot opening / closing valve having a first position communicating with the pilot flow path and a second position blocking the pilot flow path is disposed in the pilot flow path. Is located at the first position due to the non-action of the action force based on the pressure of the pilot liquid acting against the spring force, and is located at the second position due to the action, and the pilot action through which the pilot liquid acting against the spring force flows. A flow path is provided to be connected to the solenoid switching valve side of the pilot flow path from the pilot on / off valve, and the pilot operating flow path is shared by the pilot liquid introduced into the pilot open / close valve as a free flow. It is characterized in that it has arranged a one-way throttle valve for controlling throttle the pilot liquid derived from pilot-off valve. It is also possible to adjust the throttle opening of the one-way throttle valve.
[0009]
[Effects of the invention]
In the fluid control apparatus according to the present invention, when the electromagnetic switching valve is positioned at the first position by the energization / non-energization operation, the load channel is communicated with the discharge channel, the pilot channel is communicated with the supply channel, The pressure liquid flows as a pilot liquid through the pilot operating flow path from the pilot flow path, flows through the one-way throttle valve in a free flow and opposes the spring force of the pilot on-off valve, and the pilot on-off valve opposes the spring force. The primary side of the supply flow path in the storage chamber which houses the pressure reducing valve spring which is located at the second position by the acting force based on the pressure of the pressure and cuts off the pilot flow path and sets the secondary pressure of the supply flow path Part of the pressure liquid flows through the pilot branch flow path as a pilot liquid, and the pressure reducing valve does not control the pressure liquid flowing in the secondary side of the supply flow path, and the liquid actuator discharges from the load flow path. And communicates with the low pressure side via the.
[0010]
In this state, when the electromagnetic switching valve is switched from the first position to the second position by energization / non-energization operation, the load flow path is connected to the supply flow path, the pilot flow path is connected to the discharge flow path, and the pilot operating flow path is The pilot fluid communicates with the discharge passage from the pilot passage, but the pilot liquid that opposes the spring force of the pilot opening / closing valve is led out by being controlled by the one-way throttle valve. The pressure reducing valve depressurizes the pressure liquid flowing in the secondary side of the supply flow path by introducing the pilot liquid into the storage chamber in the same manner as described above until switching to the first position and the pilot opening / closing valve to the first position. The pressure liquid that is not controlled and that is not pressure-reduced is introduced from the load channel to the liquid actuator.
[0011]
When the pilot on / off valve is switched to the first position, the pilot flow path is communicated, and the pilot liquid in the storage chamber of the pressure reducing valve flows from the pilot branch flow path to the low pressure side through the pilot flow path and the discharge flow path. In addition, the throttle liquid provided in the pilot branch passage restricts the pilot liquid to be introduced into the storage chamber from the primary side of the supply flow path, and the pressure reducing valve is circulated to the secondary side of the supply flow path. The liquid is controlled to be depressurized to a set pressure by a spring force, and the depressurized pressure liquid is introduced into the liquid actuator from the load channel.
[0012]
For this reason, with the switching to the second position by the energization / non-energization operation of the electromagnetic switching valve, the pilot on / off valve is gradually switched from the second position to the first position, and the pressure reducing control is performed from the state where the pressure reducing valve is not pressure controlled. Since it can be automatically switched to the state, the switching switching of the flow path and the pressure liquid can be controlled to be depressurized or not depressurized by the energization / deenergization operation of the electromagnetic switching valve, thus simplifying the operation. it can.
[0013]
Further, in the liquid control apparatus according to the present invention, the energized / deenergized valve may be one electromagnetic switching valve, and the energized / deenergized valve requires two solenoid switching valves and a pilot solenoid valve in FIG. Compared to the liquid control device, it is possible to reduce erroneous operations associated with energization / non-energization operations, and it is possible to favorably suppress malfunctions of the liquid actuator.
[0014]
Further, in the liquid control device according to the present invention, when the throttle opening of the one-way throttle valve is provided to be adjustable, the pilot on-off valve is located at the second position when switching from the second position to the first position. The time can be changed as desired, and the timing for switching the pressure reducing valve from a state where pressure reducing control is not performed to a state where pressure reducing control is performed can be changed as desired, and the apparatus can be applied to a wide range of applications.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The same parts as those in the liquid control apparatus of FIG. In FIGS. 1 and 2, 2 is a pilot on-off valve, 3 is a pressure reducing valve, 4 is an electromagnetic switching valve, and a pressure reducing valve 3 and an electromagnetic switching valve 4 are sequentially stacked on the pilot on / off valve 2. P2 is a supply flow path for supplying pressure liquid connected to the pressure source P. The flow path 6 is provided through the open / close valve body 5 of the pilot open / close valve 2 and the primary drilled through the decompression valve body 7 of the pressure reducer 3. The side flow path 8 and the secondary side flow path 9 are connected to a switching valve body 10 of the electromagnetic switching valve 4 and a perforated flow path 11 is configured. R1 is a discharge flow path connected to the low pressure side T, a flow path 12 penetrating the on-off valve body 5, a flow path 13 penetrating the pressure reducing valve body 7, and a flow path 14 drilled in the switching valve body 10. And connected. B is a load flow path connected to the single acting cylinder 1 as a liquid actuator. The flow path 15 extends through the on-off valve body 5, the flow path 16 extends through the pressure reducing valve body 7, and the switching valve body 10. It is configured by connecting to a predetermined flow path 17. The single-acting cylinder 1 is a clamping device that clamps the workpiece W, and has a working chamber 1B for introducing and leading the pressure liquid, a spring 1A facing the working chamber 1B, and clamping the workpiece W with the force of the spring 1A. Provided. A is a pilot channel through which a pilot liquid flows, and a channel 18 drilled in the on-off valve body 5, a channel 19 penetrating the pressure reducing valve body 7, and a channel 20 drilled in the switching valve body 10. Are connected and configured.
[0016]
The electromagnetic switching valve 4 includes a solenoid S, and communicates the load channel B with the discharge channel R1, the pilot channel A with the supply channel P2, and the load channel B with the first channel X and the supply channel P2. The pilot channel A has a second position Y that communicates with the discharge channel R1, and can be switched between a first position X and a second position Y by energization / non-energization operation to the solenoid S.
[0017]
The pressure reducing valve 3 is disposed in the supply flow path P2, and the pressure reducing valve body 7 is provided with a sliding hole 21 in which the primary side flow path 8 and the secondary side flow path 9 are opened with a gap in the axial direction. The pressure reducing valve body 22 is inserted in the sliding hole 21 so as to be slidable in the axial direction. Reference numeral 23 denotes a lid member fixed to one side surface of the pressure reducing valve body 7, which closes one end opening of the sliding hole 21 to define a working chamber 24 at one end of the pressure reducing valve body 22. And is connected to the secondary side flow path 9. 26 is a housing member fixed on the other side of the pressure reducing valve body 7, the other end opening of the sliding hole 21 is closed, and a housing chamber 27 is defined at the other end of the pressure reducing valve body 22. 27 includes springs 28 and 29 for setting the pressure of the secondary channel 9. Reference numeral 30 denotes an adjustment member that changes and adjusts the forces of the springs 28 and 29, and is provided so as to be screwed to the housing member 26 so as to be rotatable. 31 is a relief passage formed in the pressure reducing valve body 22, which communicates with the housing chamber 27 and has one end opened to the outer peripheral surface of the pressure reducing valve body 22, and this one end opening is normally the inner peripheral surface of the sliding hole 21. 2 and when the pressure of the secondary side flow path 9 rises to the set pressure or higher by the force of the springs 28 and 29, the pressure reducing valve body 22 communicates with the secondary side flow path 9 as it slides to the right in FIG. Is provided.
[0018]
The pressure reducing valve 3 maximizes the opening degree H formed between the pressure reducing valve 22 and the sliding hole 21 by introducing a pilot liquid, which will be described later, into the housing chamber 27 and the pressure reducing valve body 22 is located at the left end of FIG. The pressure liquid flowing through the secondary side flow path 9 is not controlled to be depressurized, and the pressure reducing valve body 22 is operated based on the pressure of the pressure liquid in the working chamber 24 and the spring 28 by derivation of the pilot liquid from the collection chamber 27. 2 is slid rightward in FIG. 2 to an equilibrium position with 29 force to reduce the opening H, or the flow path 31 communicates with the secondary flow path 9 to flow through the secondary flow path 9. The pressure liquid is provided so as to be pressure-reduced to a set pressure by the springs 28 and 29.
[0019]
The pilot open / close valve 2 has a first position X1 that communicates with the pilot flow path A and a second position Y1 that blocks the pilot flow path A, and the open / close valve main body 5 has a flow path 6 constituting the supply flow path P2. A pilot branch channel 32 that branches and connects to the storage chamber 27 of the pressure reducing valve 3 is formed, and a throttle unit 33 that throttles and controls the pilot liquid that flows is provided in the pilot branch channel 32. Reference numeral 34 denotes a bottomed sliding hole, which is provided in the opening / closing valve body 5 in a direction perpendicular to the direction in which each of the flow paths 6, 12, 15 penetrates and opened on one side surface. The sliding hole 34 opens the flow path 18 constituting the pilot flow path A, and is confined to the throttle portion 33 of the pilot branch flow path 32 at a position having a gap in the axial direction from the opening position of the flow path 18. An opening is provided between the chambers 27, whereby the pilot channel A is connected between the throttle 33 of the pilot branch channel 32 and the collection chamber 27.
[0020]
An open / close valve body 35 is inserted into the sliding hole 34 so as to be slidable in the axial direction. The pilot flow path A is provided so as to be able to cut off the communication, and is biased in the communication direction of the pilot flow path A by a spring 36 force. A piston member 37 is provided on the head. 38 is a sub-valve main body fixed on one side of the on-off valve main body 5, the opening of one end of the sliding hole 34 is closed, and a working chamber 39 is defined by a piston member 37 at one end of the on-off valve body 35. The chamber 39 is provided with a pilot liquid that opposes the force of the spring 36 and that acts on the opening / closing valve body 35. Reference numeral 40 denotes a pilot operating flow path through which a pilot liquid that opposes the force of the spring 36 circulates. The pilot operating flow path is formed in the opening / closing valve body 5 at the same position in the axial direction as the position where the pilot flow path A of the sliding hole 34 opens. A flow path 41 that is open and connected to the pilot flow path A is connected to a flow path 42 that is drilled in the sub-valve main body 38 and connected to the working chamber 39. The pilot operating channel 40 is connected to the pilot channel A by opening the channel 41 at the same location in the axial direction as the location of the pilot channel A of the sliding hole 34 as shown in FIG. Thus, the pilot on-off valve 2 in the pilot passage A is connected to the electromagnetic switching valve 4 side.
[0021]
43 is a one-way throttle valve disposed in the flow path 42 of the sub-valve main body 38 that constitutes the pilot operating flow path 40. The pilot liquid introduced into the working chamber 39 is free flow and the pilot liquid is led out from the working chamber 39. A check valve 44 for blocking and a variable throttle valve 45 for throttle-controlling the pilot liquid led out from the working chamber 39 are arranged in parallel, and the variable throttle valve 45 can freely adjust the throttle opening degree by rotating operation. Provided. The pilot opening / closing valve 2 is positioned at the second position Y1 against the force of the spring 36 by introducing the pilot liquid into the working chamber 39, and when the pilot liquid is led out from the working chamber 39, the pilot liquid is one-way throttle valve. Since the aperture is controlled at 43 and derived, it is provided so as to be gradually switched from the second position Y1 to be positioned at the first position X1.
[0022]
Next, the operation of this configuration will be described. In the state of FIG. 1, no pressure liquid is supplied to the supply flow path P2, the electromagnetic switching valve 4 is located at the first position X without energizing the solenoid S, and the pilot opening / closing valve 2 is placed in the working chamber 39 with the pilot liquid. Is not introduced and is located at the first position X1 by the spring 36 force, the pressure reducing valve 3 is located at the left end of FIG. In the cylinder 1, the working chamber 1B communicates with the low pressure side T from the load flow path B through the discharge flow path R1, and the work W is clamped by the force of the spring 1A.
[0023]
When the pressure liquid is supplied from the pressure source P to the supply flow path P2, a part of the pressure liquid in the supply flow path P2 flows as a pilot liquid through the pilot branch flow path 32 and is introduced into the storage chamber 27 of the pressure reducing valve 3. In addition, the pilot channel A, the pilot operating channel 40, and the one-way throttle valve 43 flow through the electromagnetic switching valve 4 located at the first position X from the supply channel P2, and are introduced into the working chamber 39 to open and close the pilot. The valve 2 is switched from the first position X1 to the second position Y1 against the force of the spring 36 by the acting force based on the pressure of the pilot liquid introduced into the working chamber 39, and the pressure reducing valve 3 is supplied with the pilot liquid into the storage chamber 27. While the pressure reducing valve body 22 is introduced and the pressure valve body 22 is positioned at the left end shown in FIG. The single acting cylinder 1 clamps the workpiece W with the spring 1A force as described above.
[0024]
From this state, when the solenoid S of the electromagnetic switching valve 4 is energized to switch from the first position X to the second position Y, the load flow path B is connected to the supply flow path P2 and the pilot flow path A is discharged to the discharge flow path R1. The working chamber 39 of the pilot open / close valve 2 communicates with the discharge operating flow path 40 and the pilot flow path A to the discharge flow path R1, but the pilot liquid in the working chamber 39 is controlled to be throttled by the one-way throttle valve 43. Therefore, the pilot on / off valve 2 is gradually switched from the second position Y1 to the first position X1 by the force of the spring 36 until the pilot on / off valve 2 is switched to the first position X1 (corresponding to the time T1 shown in FIG. 3). In the same manner as described above, the pressure reducing valve 3 does not control pressure reduction of the pressure liquid introduced into the storage chamber 27 and flows through the supply flow path P2, and does not perform pressure reduction control (pressure is set to P3 in FIG. 3). (Shown) is load channel B 1 is introduced into the working chamber 1B of the single acting cylinder 1, and the single acting cylinder 1 moves to the right in FIG. Then, the workpiece W is unclamped, and the workpiece W is replaced with a new one.
[0025]
When the pilot valve 2 is switched to the first position X1 after the time T1 shown in FIG. 3 has elapsed, the pilot liquid in the storage chamber 27 of the pressure reducing valve 3 communicates with the pilot flow path A, and the pilot liquid flows. The pilot liquid flowing through the pilot flow path A and the discharge flow path R1 from the passage 32 is led out to the low pressure side T, and the pilot liquid to be introduced into the storage chamber 27 through the pilot branch flow path 32 from the supply flow path P2 is throttled. The pressure reducing valve 3 is opened by sliding the pressure reducing valve body 22 in the right direction in FIG. 2 to an equilibrium position of the acting force based on the pressure of the pressure liquid in the working chamber 24 and the springs 28 and 29. The flow path 31 communicates with the secondary side flow path 9 while setting H to 0, and the pressure liquid of the secondary side flow path 9 flows from the flow path 31 through the storage chamber 27 to the low pressure side T, The pressure liquid flowing through the supply flow path P2 by reducing H or the force of springs 28 and 29 Then, the pressure liquid under pressure control (the pressure is indicated by P4 in FIG. 3) is introduced into the working chamber 1B of the single-acting cylinder 1 from the load channel B, and is introduced into the working chamber 1B. The acting force based on the pressure of the pressurized liquid is slightly lower than the spring 1A force, and the single-acting cylinder 1 gradually moves in the left direction in FIG. At this time, the pressure liquid in the working chamber 1 </ b> B flows gradually through the flow path 31 through the communication of the flow path 31 to the secondary-side flow path 9.
[0026]
In this state, when the solenoid S of the electromagnetic switching valve 4 is deenergized and switched from the second position Y to the first position X shown in FIG. 1, the pressure liquid in the working chamber 1B is discharged from the load flow path B to the discharge flow path R1. The single-action cylinder 1 clamps a new workpiece W by the force of the spring 1A. The pilot opening / closing valve 2 flows from the supply flow path P2 through the pilot flow path A and the pilot operation flow path 40, and the pilot liquid is introduced into the working chamber 39 to switch to the second position Y1, and then the pressure is applied to the supply flow path P2. When the liquid is not supplied, the pilot on-off valve 2 returns to the first position X1 shown in FIG.
[0027]
With this operation, the pilot on-off valve 2 is positioned at the second position Y1 during the time T1 and then moved to the first position X1 as the solenoid switching valve 4 is switched to the second position Y by energizing the solenoid S. By switching, it is possible to automatically switch the pressure reducing valve 3 from a state where pressure reducing control is not performed to a state where pressure reducing control is performed, so that the flow paths P2, A, B, R1 are controlled by the energization / non-energization operation to the solenoid S of the electromagnetic switching valve 4. The switching communication and the pressure liquid can be controlled to be decompressed or not controlled, and the operation can be simplified. Further, only one solenoid switching valve 4 may be energized and de-energized. Compared to the liquid control device of FIG. 4 which requires two solenoid switching valves and a pilot solenoid valve, the energization / non-energization valve is required. The erroneous operation associated with the energization operation can be reduced, and the malfunction of the single acting cylinder 1 can be satisfactorily suppressed. Furthermore, the second position when the pilot on-off valve 2 is switched from the second position Y1 to the first position X1 by rotating the variable throttle valve 45 of the one-way throttle valve 43 to adjust the throttle opening degree. The time T1 positioned at Y1 can be changed as desired, and the timing of switching the pressure reducing valve 3 from the state where pressure reducing control is not performed to the state where pressure reducing control is performed can be changed as desired, so that the liquid control device can be applied to a wide range of applications.
[0028]
In the above-described embodiment, the liquid control device according to the present invention is applied to the single-acting cylinder 1 that is a clamping device that clamps the workpiece W by the spring 1A. However, the liquid control device according to the present invention is applied to the machine tool shown in FIG. The same can be applied to a clamping device that clamps the main shaft 101. The clamping device shown in FIG. 5 is assembled between the outer periphery of the bearings 102 and 103 supporting the main shaft 101 and the cylinder bore provided in the machine body 104 of the machine tool so as to be liquid-tight and movable in the axial direction. Cylindrical pistons 107 and 108 forming working chambers 105 and 106 (connected to the load flow path B of the liquid control apparatus shown in FIG. 1 through a flow path 104a provided in the machine main body 104), bearings 102, 103 and the pistons 107 and 108, the main shaft 101 and the cylindrical body 111 formed by the machine main body 104 (communicated with the atmosphere through a vent 104b provided in the machine main body 104) and two pairs of sleeves 112 and 113. 114, 115 and the sleeves 112, 113 on the outer periphery, and the sleeves 112, 113 are axially directed toward the pistons 107, 108. It is constituted by four disc springs 116 for biasing.
[0029]
Each of the outer sleeves 112 and 113 has a tapered inner peripheral surface that expands toward the pistons 107 and 108 on the inner periphery, and on the outer periphery of each sleeve 114 and 115 on the inner periphery on the tapered inner peripheral surface. The taper is fitted to the formed outer peripheral surface of the taper, and the diameter is expanded by a wedge action generated in the taper fitting portion, and is fixed to the machine body 104 by pressure contact. The inner sleeves 114 and 115 reduce the diameter by the wedge action when the outer sleeves 112 and 113 move away from each other in the axial direction, and clamp the main shaft 101 from the outer periphery on the inner cylindrical surface. The movement in the axial direction separating from each other by the bearings 102 and 103 is restricted, and axial communication grooves 114a and 115a are provided on the inner periphery.
[0030]
In the clamp device of FIG. 5 configured as described above, when the load flow path B connected to the working chambers 105 and 106 communicates with the discharge passage R1 shown in FIG. It is not pushed by the two pistons 107 and 108 but is pressed in the axial direction away by the force of the disc spring 116 to increase the diameter by the wedge action and to reduce the diameter of the sleeves 114 and 115. For this reason, the main shaft 101 is clamped from the outer periphery by both sleeves 114 and 115 and fixed to the machine main body 104 via the sleeves 112 to 115. In this state, when the pressure liquid not subjected to pressure reduction control indicated by P3 in FIG. 3 is introduced into the working chambers 105 and 106 from the liquid control device shown in FIGS. 1 and 2, the pistons 107 and 108 are moved to the sleeves 112 and 113, respectively. Since the sleeves 112 and 113 are moved in the axial direction against the force of the disc spring 116, the wedge action disappears, and the main shaft 101 is released from being fixed by the sleeves 112 to 115 and the disc spring 116. It becomes unclamping. Then, after the time T1 shown in FIG. 3 has elapsed, the pressure of the pressure liquid supplied from the liquid control device shown in FIGS. 1 and 2 to the working chambers 105 and 106 is controlled to be reduced as indicated by P4 in FIG. Although the pressure becomes a pressure, the force for contracting and holding the disc spring 116 remains, so that the unclamping can be maintained as it is, and a good unclamping state is obtained.
[0031]
In the clamping device of FIG. 5, when the pressure of P3 is maintained, radial forces are generated from the sleeves (wedges) 112 to 115, and it is not easy to obtain a good unclamped state. In this case, after unclamping with the pressure of P3, the pressure in the radial direction can be reduced by reducing the pressure to the pressure of P4, and a good unclamped state can be easily achieved.
[0032]
In the above-described embodiment shown in FIGS. 1 and 2, the pressure reducing valve 3 is a direct acting type, but may be a pilot operated type, and the one-way throttle valve 43 has a variable throttle valve 45 with an adjustable throttle opening. Of course, a fixed throttle valve with a constant throttle opening may be provided. Moreover, in the said embodiment, although the liquid control apparatus by this invention was implemented for the use whose liquid actuator is a clamp apparatus, the liquid control apparatus by this invention is similarly or suitably changed also for the use where a liquid actuator is other than a clamp apparatus. Can be implemented.
[Brief description of the drawings]
FIG. 1 is a circuit diagram showing an embodiment of a liquid control apparatus according to the present invention.
FIG. 2 is a longitudinal sectional view showing a detailed configuration of the liquid control apparatus shown in FIG.
3 is an explanatory diagram showing the relationship between the operating state of an electromagnetic switching valve, the pressure of a supply flow path, and the elapsed time in the liquid control apparatus shown in FIGS. 1 and 2. FIG.
FIG. 4 is a circuit diagram showing an example of a liquid control apparatus configured using a conventionally known pressure reducing valve.
FIG. 5 is a cross-sectional view showing an example of a spindle clamping device of a machine tool whose operation is controlled by the liquid control device according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Single acting cylinder (liquid actuator), 2 ... Pilot open / close valve, 3 ... Pressure reducing valve, 4 ... Electromagnetic switching valve, 27 ... Storage chamber, 28, 29 ... Spring, 32 ... Pilot branch flow path, 33 ... Restriction part , 36 ... Spring, 40 ... Pilot operating channel, 43 ... One-way throttle valve, P2 ... Supply channel, R1 ... Discharge channel, A ... Pilot channel, B ... Load channel, T ... Low pressure side, X ... 1st position of electromagnetic switching valve, Y ... 2nd position of electromagnetic switching valve, X1 ... 1st position of pilot on-off valve, Y1 ... 2nd position of pilot on-off valve.

Claims (3)

A supply flow path for supplying pressure liquid, a discharge flow path connected to the low pressure side, a load flow path connected to the liquid actuator, and a pilot flow path through which the pilot liquid flows are provided, and the load flow path is used as the discharge flow path. A first position that communicates the pilot channel with the supply channel and a second position that communicates the load channel with the supply channel and communicates the pilot channel with the discharge channel. An electromagnetic switching valve provided to be switchable between a first position and a second position, and a pressure reducing valve disposed in the supply flow path, and the pressure reducing valve accommodates a spring for setting the secondary pressure of the supply flow path. A collection chamber is provided, and a pilot branch channel that connects the collection chamber to the primary side of the supply channel is provided. The throttle branch channel is provided with a throttle, and between the throttle and the collection chamber. The pilot flow path is connected and provided in the pilot flow path. A pilot opening / closing valve having a first position communicating with the pilot passage and a second position blocking the pilot flow path is provided, and the pilot opening / closing valve has no acting force based on the pressure of the pilot liquid acting against the spring force. Is located at the first position and is located at the second position by the action, and connects the pilot operating flow path through which the pilot liquid acting against the spring force flows from the pilot opening / closing valve of the pilot flow path to the electromagnetic switching valve side. A liquid control device is provided in which a one-way throttle valve is provided in the pilot operating channel to allow the pilot liquid introduced into the pilot on-off valve to flow freely and to control the pilot liquid led out from the pilot on-off valve. . The liquid control apparatus according to claim 1, wherein a throttle opening degree of the one-way throttle valve is provided to be adjustable. The liquid control device according to claim 1, wherein the liquid actuator is a clamp device that clamps a workpiece or a spindle of a machine tool.

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