JP2004017193A - Work chuck device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a work chuck device for gripping a work without deforming the same and reducing a chuck open and close time. <P>SOLUTION: This device is provided with: a chuck including a plurality of chuck members 8 and gripping the work W; a cylinder device 7 opening and closing the chuck members 8; and a pressurized fluid supply circuit 13. The pressurized fluid supply circuit 13 is provided with a high low pressure switching means 18 switching pressure of fluid supplied to the cylinder device 7 to high pressure or low pressure. A circuit control means 25 controlling the pressurized fluid supply circuit 13 is provided with a high low pressure switching control means 26. The high low pressure switching control means 26 controls the high/low pressure switching means 18 to maintain a transmitting route part Sa in a side from a middle position of a transmitting route which is opened and closed by the chuck 5 to grip the work W at low pressure and a transmitting route part Sb in a side far from the work W at high pressure. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a work chuck device for chucking a work in a lathe or other machine tools.
[0002]
[Prior art]
In a work chuck device such as a spindle chuck of a lathe, a fluid pressure cylinder device is used for opening and closing chuck members such as chuck claws. The fluid pressure for driving the chuck cylinder device is set to an appropriate pressure according to the chuck size, the assumed work weight, and the like, and is set to a low pressure or a high pressure throughout the opening and closing stroke of the chuck.
[0003]
[Problems to be solved by the invention]
However, when the pressure is high, the work may be distorted by the gripping force of the chuck member depending on the shape of the work. For example, in the case of a cylindrical work or the like, if the thickness of the work is thin, distortion may occur. When the fluid pressure is low, the chuck opening / closing time may be long due to the resistance of the chuck opening / closing. In particular, when a small work is gripped by a large-sized chuck, the opening and closing time of the chuck is unnecessarily long.
[0004]
SUMMARY OF THE INVENTION An object of the present invention is to provide a work chuck device capable of gripping a work without distorting and shortening a chuck opening / closing time.
Another object of the present invention is to be able to instruct high / low pressure switching timing without providing a dedicated detection mechanism such as a sensor or a switch for detecting a middle position of the chuck member.
[0005]
[Means for Solving the Problems]
The configuration of the present invention will be described with reference to FIG. 1 corresponding to the embodiment. The work chuck device includes a plurality of chuck members (8) that can freely open and close and has a chuck (5) capable of holding a work (W) in a closed state, and a cylinder device (open and close) for opening and closing the chuck members (8). 7) and a pressure fluid supply circuit (13) for supplying a pressure fluid to the cylinder device (7), having the following configuration. That is, high and low pressure switching means (18) provided in the pressure fluid supply circuit (13) for switching the fluid pressure supplied to the cylinder device (7) between high pressure and low pressure, and the pressure fluid supply circuit (13) A circuit control means (25) for controlling, and a movement path portion provided on the circuit control means (25), on a side where the workpiece (W) is gripped from an intermediate position of the movement path (S) in which the chuck (5) opens and closes. High and low pressure switching control means (26) for controlling the high and low pressure switching means (18) so that (Sa) has a low pressure and the moving path portion (Sb) farther from the work (W) has a high pressure. Shall be provided.
According to this configuration, by the high / low pressure switching control means (26), the moving path portion (Sa) on the side where the workpiece (W) is gripped from the intermediate position of the moving path (S) where the chuck (5) is opened / closed has a low pressure. The high / low pressure switching means (18) is controlled so that the moving path portion (Sb) on the far side with respect to (W) has a high pressure. Therefore, the work (W) is gripped at a low pressure, and the work (W) can be gripped without being distorted. Since the chuck member (8) is moved at a high pressure while the work (W) is not pressed, the chuck member (8) can be moved at a high speed, and the entire movement path (S) can be moved at a low pressure. The opening and closing time of the chuck is reduced as compared with the case of moving.
[0006]
In the present invention, the circuit control means (25) is configured to supply a pressure fluid to the cylinder device (7) in accordance with an opening / closing command (Q1, Q2) for moving the chuck member (8). 13) may be controlled. In this case, the high / low pressure switching control means (25) may control the high / low pressure switching means (18) to perform high / low pressure switching after a set time from when the opening / closing command (Q1, Q2) is received. good.
As described above, when the high / low pressure switching is performed after a set time after receiving the opening / closing command, the high / low pressure is not provided without providing a dedicated detection mechanism such as a sensor or a switch for detecting an intermediate position of the chuck member (8). Can be instructed. The set time can be set by, for example, a timer (27).
[0007]
Further, in the present invention, a timer (27) for storing a set time is provided, and the high / low pressure switching control means (26) is configured to set the timer (27) after the chuck member (8) starts moving. The high / low pressure switching means (18) may be controlled so as to perform high / low pressure switching after a lapse of time.
Thus, even when the timer (27) is provided, the high / low pressure switching timing can be instructed without providing a dedicated detection mechanism such as a sensor or a switch for detecting the middle position of the chuck member (8). The start of the movement of the chuck member (8) can be obtained from, for example, a detection signal of the operation of the cylinder device (7).
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is an explanatory diagram showing a cross section of a main spindle portion of a machine tool including the work chuck device and a conceptual configuration of a control system. The main shaft 1 is rotatably supported by a headstock 2 via a bearing 3, and is rotationally driven at a rear portion by a main shaft motor (not shown) via a transmission system 4 such as a pulley. The spindle 1 is provided with a chuck 5 for gripping the work W at its tip, and is opened and closed by a fluid pressure cylinder device 7 through a chuck draw bar 6 penetrating through the spindle 1 composed of a hollow shaft.
[0009]
The chuck 5 has a plurality of chuck members 8 which can be freely opened and closed, and can grip the workpiece W in a state where the chuck members 8 are closed. The chuck member 8 includes a chuck claw or the like. The chuck 5 has a chuck body 9 attached to the front end of the spindle 1 on the back surface, and the chuck members 8 are provided on the front surface of the chuck body 9 via guide means (not shown) such as guide grooves in the radial direction. It is installed movably. The chuck members 8 are provided, for example, at three or four positions in the circumferential direction. The chuck body 9 is provided with an operation conversion mechanism 10 for converting the forward / backward movement of the chuck drawbar 6 into the above-mentioned radial forward / backward movement of each chuck member 8. The chuck member 8 moves to the chuck shaft side when the chuck draw bar 6 is pulled, and moves to the outer diameter side when pressed. The motion conversion mechanism 10 includes, for example, a plurality of rotation levers 10 a rotatably supported by the chuck body 9 corresponding to the chuck members 8 and one end of each rotation lever 10 a provided at the tip of the chuck draw bar 6. It comprises a lever engaging member 10b for swinging, and an engaged member 10c provided on each chuck claw 8 and receiving operation transmission from the other end of the rotating lever 10a.
[0010]
In the cylinder device 7, a cylinder body 7 a is installed on the headstock 2 via a mounting member (not shown), and a piston rod having a piston 7 b is connected to the chuck draw bar 6. The cylinder device 7 is a double-acting type in which a pressure fluid is supplied and discharged from a pressure fluid supply circuit 13 to a top fluid pressure chamber 11 and a bottom fluid pressure chamber 12 which are separated from each other by a piston 7b in the cylinder chamber. Have been. For example, oil is used as the pressure fluid.
[0011]
The pressure fluid supply circuit 13 is capable of switching and supplying the fluid in the tank 14 to both the fluid pressure chambers 11 and 12 of the cylinder device 7 via the direction switching valve 16 by the pump 15. The direction switching valve 16 is, for example, an electromagnetic valve. The fluid discharged from the fluid pressure chambers 11 and 12 of the cylinder device 7 is returned to the tank 14 from the direction switching valve 16. The pump 15 is driven by a motor 17. The pressure fluid supply circuit 13 is provided with high / low pressure switching means 18 for switching the fluid pressure supplied to the cylinder device 7 between high pressure and low pressure. The high / low pressure switching means 18 is provided in the pump side circuit portion 13 a from the pump 15 to the cylinder device 7 in the pressure fluid supply circuit 13, and is disposed closer to the pump 15 than the direction switching valve 16. The high / low pressure switching means 18 is constituted by, for example, a single pressure control valve or a combination of a plurality of control valves. As the pressure control valve, for example, a relief valve or a pressure reducing valve is used, and an electromagnetic valve is used. The pressure fluid supply circuit 13 is a part of a circuit that supplies pressure fluid to the entire machine tool, and the motor 15 is also used for supplying pressure fluid to each part of the machine tool.
[0012]
FIG. 2 shows a specific example of the pressure fluid supply circuit 13 of FIG. The directional control valve 16 uses a 4-port 2-position or 3-position solenoid valve. In the case of three positions, a switching position at which each port is closed is added. The high / low pressure switching means 18 is provided in a branch circuit 13aa branched from the pump-side circuit portion 13a of the pressure fluid supply circuit 13, and includes a pressure control valve 18a and a circuit flowing into the pressure control valve 18a in a passing state and a built-in state. And a switching valve 18b for switching to a check state by a check valve. This switching valve 18b serves as a high / low pressure switching valve. The pressure control valve 18a is composed of a pressure reducing valve, and a return path 13ab of the pressure control valve 18a is connected to the tank side circuit 13b. The tank-side circuit 13b is a circuit portion from the cylinder device 7 to the tank 14 in the pressure fluid supply circuit 13. Note that another pressure control valve 19 is interposed in the pump-side circuit portion 13a, and the branch circuit 13aa is provided to branch off from the other pressure control valve 19. The pressure control valve 19 is composed of, for example, a relief valve.
2 is a state in which the chuck of the cylinder device 7 is closed. The high / low pressure switching means 18 is in a position where the high / low pressure switching valve 18b is in the check state shown in FIG. 9A, the built-in check valve functions, no branch flow occurs, and the pump side circuit portion 13a is maintained at a high pressure. When the high / low pressure switching valve 18b is switched to the passing state shown in FIG. 8B, the pressure control valve 18a functions, and the pump side circuit portion 13a is brought into the low pressure state.
[0013]
The control system will be described with reference to FIG. The machine control device 21 is a device that controls the entire machine tool, and includes a numerical control device 22 and a programmable controller 23. The machine control device 21 is of a computer type, and decodes and executes the machining program 24 by the numerical control device 22 to control each axis of the machine tool. Each of the shafts is, for example, a motor for moving back and forth in each direction of a tool rest (not shown), a spindle motor, or the like. Each sequence command in the machining program 24 is transferred from the numerical controller 22 to the programmable controller 23, and is executed according to a predetermined sequence set in the programmable controller 23. A circuit controller 25 is provided in the programmable controller 23.
[0014]
The circuit control unit 25 is a unit that controls the pressure fluid supply circuit 13 and controls supply and discharge of the pressure fluid to and from the chuck cylinder device 7. As one of the controls, switching control of the direction switching valve 16 is performed. In this case, the circuit control means 25 controls the pressure fluid supply circuit 13 so that the pressure fluid is supplied to the cylinder device 7 in accordance with the opening / closing commands Q1 and Q2 for moving the chuck member 8. The opening / closing commands Q1 and Q2 are, for example, commands described in the machining program 24, and include an opening / closing command Q1 serving as a clamp command and an opening / closing command Q2 serving as an unclamping command.
[0015]
The high / low pressure switching control means 26 determines that the moving path portion Sa on the side that grips the workpiece W (that is, the chuck center side) has a low pressure from the middle position of the moving path S of the chuck member 8 that the chuck 5 opens and closes. This is a means for controlling the high / low pressure switching means 18 so that the moving path portion Sb on the far side (that is, the outer diameter side of the chuck) has a high pressure. Therefore, the high / low pressure switching control means 26 sets the high / low pressure switching means 18 to the high pressure state when the chuck 5 is open, and sets the high / low pressure switching means 18 to the low pressure state when the chuck 5 is closed. The chuck open state refers to a maximum open state or an open state with a predetermined opening degree. The chuck closed state is a state in which the work W can be gripped by the chuck 5 to a close degree.
[0016]
Further, the high / low pressure switching control means 26 controls the high / low pressure switching means 18 so as to perform high / low pressure switching after a set time from when the opening / closing commands Q1 and Q2 are received. The time when the opening / closing commands Q1 and Q2 are received is when the high / low pressure switching control means 26 receives the commands Q1 and Q2. Specifically, the opening / closing commands Q1 and Q2 of the machining program 24 are programmable. According to the sequence provided by the controller 23, the state becomes executable and is transmitted to the high / low pressure switching control means 26. In this case, when receiving the opening / closing command Q1 as a clamp command, the high / low pressure switching control means 26 controls the high / low pressure switching means 18 so that the pressure becomes low after a set time. When the opening / closing command Q1 serving as a clamp command is received, the chuck 5 is in the open state, and in this open state, the high / low pressure switching means 18 is set to the high pressure by the high / low pressure switching control means 26 as described above. When receiving the opening / closing command Q2 serving as an unclamping command, the high / low pressure switching control means 26 controls the high / low pressure switching means 18 so that the pressure becomes high after a set time. When the opening / closing command Q2 serving as the unclamping command is received, the chuck 5 is in the closed state. In this closed state, the high / low pressure switching means 18 is set to the low pressure by the high / low pressure switching control means 26 as described above. The set time when switching from high pressure to low pressure and the set time when switching from low pressure to high pressure are different times, and the set time for switching from high pressure to low pressure is longer, but the reverse is true. Or the same time.
[0017]
Each of the set times is a time set in the timer 27. The timer 27 may be provided in the high / low pressure switching control means 26, may be provided in the circuit control means 25, or may be provided somewhere in the programmable controller 23. The timer 27 is provided separately from a set time for switching from high pressure to low pressure and a set time for switching from low pressure to high pressure. If the two set times are the same, a common timer 27 may be used. It is desirable that the timer 27 can change the set time by, for example, an appropriate input means or the machining program 24.
[0018]
The operation of the above configuration will be described. Now, as shown in FIG. 3C, the chuck opening / closing position indicates that the chuck 5 is in the open state, the chuck clamp command (FIG. 3A) is off, and the chuck unclamping command (B) is off. Suppose there was. The chuck clamp command is the opening / closing command Q1 in FIG. 1, and the unclamping command is the opening / closing command Q2. FIGS. 3A and 3B show the state when the high / low pressure switching control means 26 receives these commands. At this time, under the control of the high / low pressure switching control means 26, the high / low pressure switching means 18 is set to a high pressure as shown in FIG.
[0019]
Here, when the chuck clamp command is turned on, the direction switching valve 16 is opened with respect to the top side fluid pressure chamber 11 of the cylinder device 7 by the circuit control means 25, and the cylinder device 7 is driven at a high pressure. Therefore, the chuck member 8 of the chuck 5 moves to the closing side at a high speed as shown by a curved line portion c2 in FIG. When the set time T1 set by the timer 27 elapses from the ON of the chuck clamp command, the chuck member 8 becomes a predetermined intermediate position on the movement path, and at this time, the high / low pressure switching control means 26 switches the high / low pressure switching means 18 to low pressure. . Therefore, the chuck member 8 moves at a low speed as indicated by a curved portion c3 in FIG. 3C. When the chuck member 8 comes to a position where it completely grips the work W, the chuck member 8 maintains the closed position as shown by the curved portion c4. In this state of gripping the workpiece, the chuck 4 grips the workpiece W at a low pressure, so that the workpiece W is not distorted by the clamp pressure.
[0020]
When performing unclamping, the chuck clamp command is turned off (FIG. 3A), and at the same time, the chuck unclamping command is turned on (FIG. 3B). In response to the chuck unclamping command, the circuit control means 25 switches the direction switching valve 16 and supplies the pressurized fluid to the fluid pressure chamber 12 on the bottom side. At this time, the clamping pressure is low, and the chuck member 8 moves at a low speed as indicated by the curved line portion c5. When the set time T2 has elapsed from the unclamping command, the chuck member 8 is at a predetermined intermediate position on the movement path, and at this time, the high / low pressure switching control means 26 switches the high / low pressure switching means 18 to high pressure. Therefore, the chuck member 8 moves at a high speed as indicated by a curved portion c6 in FIG. 3C. When it moves to the maximum opening position that is the stroke end, it stops at that position.
[0021]
As described above, the moving path portion Sa on the side that grips the work W from the intermediate position of the moving path S (FIG. 1) in which the chuck 5 opens and closes has a low pressure, The high / low pressure switching means 18 is controlled so that the moving path portion Sb has a high pressure. Therefore, the work W is gripped at a low pressure, and the work W can be gripped without being distorted. In addition, since the chuck member 8 is moved at a high pressure while the work W is not pressed, the chuck member 8 can be moved at a high speed, and the chuck opening / closing time is shorter than when the entire moving path is moved at a low pressure. Is shortened.
[0022]
When the size of each workpiece W to be processed sequentially is constant, the setting time T1 of the timer 27 is optimized, and the pressure is set to be high just before the workpiece W is actually gripped, so that distortion due to chuck pressure is reduced. While avoiding, the chuck operation time can be reduced as much as possible.
[0023]
At the time of unclamping, that is, when giving the unclamping opening / closing command Q2, it is possible to switch back to the high pressure immediately after the opening operation of the chuck 5 or immediately after the opening operation without providing the set time T2 as shown in FIG. . Thereby, the unclamping operation can be further reduced. Immediately after the opening of the chuck 5 is started, if there is a possibility that the work W is still distorted at a high pressure, it is desirable to switch to a high pressure during the opening movement of the chuck member 8 even during unclamping as shown in FIG.
[0024]
In the above embodiment, the high / low pressure switching control means 26 controls the high / low pressure switching means 18 so as to perform the high / low pressure switching after a set time from when the opening / closing command is received. The control unit 26 may control the high / low pressure switching means 18 to perform high / low pressure switching after a set time set in the timer 27 from the start of movement of the chuck member 8. The start of the movement of the chuck member 28 can be obtained from, for example, a detection signal of the operation of the cylinder device 7 or the like. The cylinder device 7 may be provided with switches for detecting a stroke end for various purposes, and a signal from such a switch may be used as a signal for starting the movement of the chuck member 28.
[0025]
【The invention's effect】
In the work chuck device of the present invention, high-low pressure switching means for switching the fluid pressure supplied to the chuck opening / closing cylinder device between high pressure and low pressure is provided in the pressure fluid supply circuit, and the workpiece is moved from a middle position of the movement path where the chuck opens and closes. High and low pressure switching control means for controlling the high and low pressure switching means is provided so that the moving path portion on the gripping side has a low pressure and the moving path portion on the far side to the work has a high pressure, so that the work is not distorted. It can be gripped and the opening and closing time of the chuck can be reduced.
When the high / low pressure switching control means controls the high / low pressure switching means so as to perform high / low pressure switching after a set time after receiving the opening / closing command, a sensor or a switch for detecting a middle position of the chuck member may be used. The high / low pressure switching timing can be instructed without providing a detection mechanism.
A timer for storing a set time is provided, and the high / low pressure switching control means controls the high / low pressure switching means to perform high / low pressure switching after a set time set in the timer after the chuck member starts moving. Also in this case, it is possible to instruct the high / low pressure switching timing without providing a detection mechanism such as a sensor or a switch for detecting the middle position of the chuck member.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram illustrating a conceptual configuration of a main spindle portion of a machine tool including a work chuck device according to an embodiment of the present invention and a control system thereof.
FIG. 2 is a circuit diagram showing a specific example of the pressure fluid supply circuit.
FIG. 3 is a timing chart of each part of the chuck device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Spindle 5 ... Chuck 6 ... Chuck drawbar 7 ... Cylinder device 8 ... Chuck members 11, 12 ... Fluid pressure chamber 13 ... Pressure fluid supply circuit 16 ... Direction switching valve 18 ... High / low pressure switching means 19 ... Pressure control valve 23 ... Programmable Controller 24: Machining program 25: Circuit control means 26: High / low pressure switching control means 27: Timers Q1, Q2: Opening / closing command S: Moving paths Sa, Sb: Moving path portion

Claims (3)

A chuck having a plurality of chuck members capable of being opened and closed with respect to each other and capable of holding a work in a closed state, a cylinder device for opening and closing the chuck member, a pressure fluid supply circuit for supplying a pressure fluid to the cylinder device, High and low pressure switching means provided in the fluid supply circuit for switching the fluid pressure supplied to the cylinder device between high pressure and low pressure; circuit control means for controlling the pressure fluid supply circuit; and High / low pressure switching that controls the high / low pressure switching means so that the moving path portion on the side that grips the work from the middle position of the moving path that the chuck opens and closes has a low pressure, and the moving path portion on the far side with respect to the work has a high pressure. A work chuck device comprising a control unit. The circuit control means controls the pressure fluid supply circuit so that pressure fluid is supplied to the cylinder device according to an opening / closing command for moving the chuck member, and the high / low pressure switching control means receives the opening / closing command. 2. The work chuck device according to claim 1, wherein the high / low pressure switching means is controlled so as to perform the high / low pressure switching after a set time. A timer for storing a set time is provided, and the high / low pressure switching control means controls the high / low pressure switching means to perform high / low pressure switching after a set time set in the timer after the chuck member starts moving. The work chuck device according to claim 1, wherein

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