JP7195747B2 - Machine tool pallet drop prevention device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a pallet drop prevention device for a machine tool such as a machining center, and more particularly to a device for preventing a pallet from falling, which is clamped to a table of the machine tool by a clamping mechanism.

In numerically controlled (NC) machine tools such as machining centers, in order to continuously process a large number of workpieces by automatic operation, the workpieces are loaded on a pallet, and the pallet loaded with the processed workpieces is carried out from the table. Alternatively, some machines are equipped with an automatic pallet changer (hereinafter referred to as "APC") for loading pallets loaded with unprocessed workpieces in a pallet pool line or preparation station onto the table.

In order to clamp the pallet carried onto the table by the above APC, a pallet guide that moves up and down is provided on the table, the upper end of the pallet guide is formed in a T shape, and the T groove formed on the bottom surface of the pallet is clamped. After engagement, the pallet guide is lowered to clamp the pallet. Further, recently, in order to shorten the pallet exchange time, an APC that directly exchanges pallets on a table has been used (see, for example, Patent Documents 1 and 2). In these APCs, for example, a pallet loaded onto a table is lowered to transfer the pallet to an engaging position of a clamping member on the table, and press and clamp a member to be clamped provided on the lower surface of the pallet. I have to.

In recent years, in such machine tools, it is necessary to prevent the pallet from falling from the machining table when the pallet is unclamped. A safety design is made to prevent the clamped state from being released by controlling the flow of working fluid (oil) in the hydraulic circuit for clamping and unclamping with a check valve or the like.

Japanese Utility Model Publication No. 2-6965 Japanese Utility Model Publication No. 7-46433

However, for example, in a 5-axis control machining center (machine tool), unlike the conventional 4-axis control machine tool where the table was maintained in a horizontal state, the table was loaded with pallets programmed according to the machining purpose. may rotate and the table may tilt more than 90 degrees. Therefore, in addition to conventional control by valves in the hydraulic circuit of the clamping mechanism, even if an unexpected emergency occurs and the hydraulic pressure of the clamping mechanism goes down, the pallet can be prevented from falling off the table of the machine tool. Therefore, development of technology for further safety design is required.

SUMMARY OF THE INVENTION The present invention has been made in view of the circumstances described above, and its object is to provide a device capable of reliably preventing a pallet from falling from a table in a machine tool such as a machining center, particularly a five-axis control machine tool. To provide a device capable of surely preventing a pallet from falling even when a table is tilted.

In order to achieve the above object, the pallet drop prevention device of the present invention comprises an automatic pallet changer and a clamping mechanism for clamping or unclamping a pallet on a table, the clamping mechanism having a clamping cylinder, and a working fluid In a pallet drop prevention device for a machine tool that moves a pallet up and down on a table by means of a clamping piston in the clamping cylinder in response to the supply or outflow of the a fall prevention cylinder into which the working fluid is supplied or discharged in a direction opposite to the supply or outflow of the working fluid to the clamping cylinder; A fall prevention pin that extends or retracts when supplied or flowed out, an urging means that urges the fall prevention pin to extend, and an insertion hole formed in a corresponding portion of the table mounting side surface of the pallet. When the working fluid is supplied to the fall prevention cylinder, the fall prevention pin extends and is inserted into the insertion hole of the pallet, and the working fluid flows into the fall prevention cylinder. The pallet drop prevention device maintains the state of insertion into the insertion hole by extending the drop prevention pin due to the urging force of the urging means when the pallet is no longer supplied, wherein the pallet is unclamped. , wherein the fall prevention pin follows the pallet. According to this configuration, even when the supply of hydraulic oil (pressure oil) for clamping the pallet is interrupted, only the urging force of the urging means acts, so that the drop prevention pin does not retract, and the insertion hole of the pallet does not retract. Since the pallet is held in a state of being inserted into the table, it is possible to reliably prevent the pallet from falling off the table.

Further, the biasing means is a coil spring provided in the fall prevention cylinder and biasing the rear end of the fall prevention pin. According to this configuration, the pallet fall prevention device can be configured simply and inexpensively by using the coil spring as the biasing means.

According to the present invention, in a machine tool such as a machining center, a device capable of reliably preventing the pallet from falling from the table, particularly in the case of a 5-axis control machine tool, etc., in which the table is inclined, the pallet does not fall. It is possible to provide a device that can reliably prevent

1 is a cross-sectional view showing the configuration of a table of a machining center according to an embodiment of the present invention, a pallet clamp mechanism (a part thereof) on the table, and a pallet drop prevention device, in a standby state of the clamp mechanism without a pallet; indicates FIG. 2 is a cross-sectional view showing an enlarged main part of FIG. 1; 1 is a cross-sectional view showing the configuration of a table of a machining center according to one embodiment of the present invention, a pallet clamp mechanism (a part thereof) on the table, and a pallet drop prevention device thereof, in a state before the clamp mechanism receives a pallet; FIG. , that is, indicates the unclamped state of the pallet. 4 is a cross-sectional view showing an enlarged main part of FIG. 3; FIG. 1 is a cross-sectional view showing the configuration of a table of a machining center according to an embodiment of the present invention, a pallet clamp mechanism (a part thereof) on the table, and a pallet drop prevention device thereof, in a state where the clamp mechanism holds the pallet; That is, the pallet is clamped, and at this time, the drop prevention pin of the pallet drop prevention device is inserted into the pallet. 6 is a cross-sectional view showing an enlarged main part of FIG. 5; FIG. 1 is a cross-sectional view showing the configuration of a table of a machining center according to an embodiment of the present invention, a pallet clamp mechanism (part of it) on the table, and a pallet drop prevention device. Even if the pallet is unclamped, the pallet drop prevention device is activated, and even if the hydraulic pressure drops, the pin for drop prevention is held by the force of the spring, so the pallet will not drop. 8 is a cross-sectional view showing an enlarged main part of FIG. 7; FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Here, the machining center (hereinafter referred to as MC) according to the present embodiment includes an automatic pallet changer (hereinafter referred to as APC). It automatically replaces the table as a fixed body. The pallet is clamped and unclamped from the table by clamp members using a clamp and unclamp device. The pallet clamping/unclamping device is equipped with a clamping cylinder device (hereinafter referred to as cylinder), and both clamping and unclamping are performed using hydraulic oil (pressure oil) supplied from the hydraulic unit and set to a predetermined pressure. perform the operation of Further, the MC according to this embodiment is a so-called 5-axis control machine tool, and the table on which the pallet is mounted rotates or rotates during machining, so the table may be tilted during the machining operation. .

FIG. 1 is a cross-sectional view showing the configuration of an MC table 10, (a part of) a pallet clamping mechanism 100 on the table 10, and a pallet fall prevention device 200 thereof according to this embodiment. The standby state of the clamping mechanism 100 is shown. The shaded area in the figure indicates a circuit to which hydraulic pressure is applied, and the same applies to the following figures. Only FIG. 1 shows the outline of the cross section of the table 10, but other drawings show only the essential parts thereof. In addition, illustration of parts of the table 10 that are not related to the present invention is omitted. FIG. 2 is a cross-sectional view showing an enlarged main part of FIG. FIG. 3 shows the state before the clamping mechanism 100 receives the pallet, that is, the pallet unclamped state, and FIG. 4 is a cross-sectional view showing an enlarged main part of FIG. FIG. 5 shows a state in which the clamping mechanism 100 holds the pallet P, that is, a state in which the pallet P is clamped. 6 is a cross-sectional view showing an enlarged main part of FIG. 5. FIG.

Here, before describing the operation of the pallet drop prevention device 200, etc., the basic operation of the pallet clamping mechanism 100 will be described first. As shown in FIGS. 1 and 2, the MC (not shown) according to the present embodiment includes an APC (not shown in its entirety), and on the MC table 10, a part of the APC A pallet clamping mechanism 100 is provided. A supply path (hydraulic circuit) 15 for hydraulic oil (pressure oil) is formed in the table 10, and a hydraulic device (not shown) passes through this supply path (hydraulic circuit) 15 to clamp cylinders, which will be described later. Hydraulic oil (pressure oil) is supplied into the chamber 102</b>A and the fall prevention cylinder chamber 202 . 1 shows only part of the pallet clamping mechanism 100, such as the pallet support 102 of the pallet clamping mechanism 100, the clamping cylinder chamber 102A, the clamping piston 104, and hydraulic units such as hydraulic ports. In FIG. 1, the pedestal 12 of the table 10 is fixed by a plurality of bolts 106 to the clamping piston 104 of the pallet clamping mechanism 100, and the pedestal 12 is also moved up and down by the expansion and contraction (up and down) movement of the piston 104. It is

That is, as shown in FIGS. 1 and 2, in the standby state of the clamping mechanism 100 without a pallet, hydraulic oil ( Pressure oil) is supplied, and the piston 104 and the base 12 are not raised. Next, as shown in FIGS. 3 and 4, in the state before the clamping mechanism 100 receives the pallet P, that is, in the state in which the pallet P is unclamped, a cylinder chamber 102A for clamping includes a cylinder as indicated by diagonal lines in the same drawing. Hydraulic oil (pressure oil) is supplied through the path, the piston 104 and the pedestal 12 are raised, and the pedestal 12 is raised from the pallet support 102 so that the pallet P can be received. Subsequently, as shown in FIGS. 5 and 6, when the clamping mechanism 100 holds the pallet P, hydraulic oil (pressure oil) flows into the clamping cylinder chamber 102A along a path indicated by diagonal lines in the drawing. The piston 104 and the pedestal 12 are lowered, the pedestal 12 is lowered to the pallet support 102, and the pallet P is clamped. Then, the workpiece (not shown) mounted on the pallet P in this clamped state is subjected to NC processing by various tools (not shown) of the MC. When the machining is completed, the pallet P carrying the machined work is replaced by the next pallet carrying the unmachined work by the clamping mechanism 100 operating in reverse order. In each drawing and the above description, the detailed configuration and parts for clamping the pallet P by the clamping mechanism 100 are not shown, and the description thereof is also omitted.

By the above operation, the MC according to the present embodiment automatically exchanges the pallet by the APC. In order to prevent the pallet P from falling off the table 10 when the pallet P is unclamped, hydraulic oil (pressure It also has a safety design that controls the flow of oil) with a check valve or the like to prevent the clamped state from being released. However, in the MC according to the present embodiment, in addition to the safety design by this valve etc., even if an unexpected emergency situation occurs and the hydraulic pressure of the clamping mechanism goes down, the pallet P will fall from the table 10 of the MC. A pallet drop prevention device 200 is provided as a further safety design (fail-safe design) so that it can be prevented.

That is, as shown in FIGS. 1 and 2, the MC according to this embodiment has a pallet drop prevention device 200 in the pallet clamping mechanism 100 of the APC (not shown in its entirety). The prevention device 200 includes a fall prevention cylinder chamber 202 provided inside the clamp piston 104 in the clamp cylinder chamber 102A, a fall prevention piston (pin) 204, and a fall prevention piston (pin). It has a coil spring 206 as a biasing means of 204 . The pallet fall prevention device 200 also has ports 208 and 209 for supplying working oil (pressure oil) into the fall prevention cylinder chamber 202 through different paths. Furthermore, as a part of the pallet fall prevention device 200, a fall prevention insertion hole Ph into which a fall prevention piston (pin) 204 is inserted is formed in a corresponding portion of the lower surface of the pallet P.

Next, the operation and effects of the pallet drop prevention device 200 will be described. The operation of the pallet fall prevention device 200 is characterized by the supply of hydraulic oil (pressure oil) into the fall prevention cylinder chamber 202 and the supply of hydraulic oil (pressure oil) into the clamp cylinder chamber 102A. , inverse timing, that is, a so-called trade-off relationship. That is, as shown in FIGS. 1 and 2, first, in the standby state of the clamping mechanism 100 without a pallet, as described above, in the clamping cylinder chamber 102A of the clamping mechanism 100, there is a path indicated by hatched lines in the same figure. , the clamping piston 104 and the pedestal 12 are not raised, but hydraulic oil (pressure oil) is supplied from the port 208 into the drop prevention cylinder chamber 202 to prevent the drop. The piston (pin) 204 protrudes from the pedestal 12 by this hydraulic pressure.

Next, as shown in FIGS. 3 and 4, in the state before the clamping mechanism 100 receives the pallet P, that is, in the state in which the pallet P is unclamped, the paths shown by hatched lines in the drawings are in the clamping cylinder chamber 102A. Hydraulic oil (pressure oil) is supplied, and the clamping piston 104 and the pedestal 12 rise from the pallet support 102 so that the pallet P can be received. When (pressure oil) is supplied, the fall prevention piston (pin) 204 descends and retracts into the fall prevention cylinder chamber 202 .

5 and 6, when the clamping mechanism 100 holds the pallet P, hydraulic oil (pressure oil) is supplied into the clamping cylinder chamber 102A through the hatched path in the same figure. , the clamping piston 104 and the pedestal 12 are lowered to the pallet support 102, and the pallet P is clamped. The drop prevention piston (pin) 204 is protruded from the pedestal 12 by this hydraulic pressure, and is inserted into the drop prevention insertion hole Ph on the lower surface of the pallet P. In this state, the workpiece (not shown) mounted on the pallet P is subjected to NC machining by various MC tools (not shown). When the machining is completed, the clamping mechanism 100 and the pallet drop prevention device 200 operate in reverse to replace the pallet P carrying the machined work with the pallet carrying the next unmachined work by APC.

Now, in the MC according to this embodiment, in addition to the safety design using the valves and the like described above, as shown in FIGS. Since the pallet fall prevention device 200 is operating, the pallet P can be prevented from falling from the table 10. - 特許庁That is, in the MC according to the present embodiment, the clamped state is maintained even if the hydraulic system stops due to a power failure or the like due to the function of the above-described safety-designed check valve. As shown in FIGS. 7 and 8, even when the supply of hydraulic oil (pressure oil) to the supply path (hydraulic circuit) is cut off, the coil spring 206 as a biasing means (spring force) is applied because there is no hydraulic pressure. As a result of the action of only the force), the drop prevention piston (pin) 204 does not retract and is held in a state of being inserted into the drop prevention insertion hole Ph on the lower surface of the pallet P, so that the pallet P is removed from the table 10 No falling. Therefore, according to the MC pallet drop prevention device 200 according to the present embodiment, an unexpected situation occurs such that the hydraulic path is damaged, and the supply of hydraulic oil (pressure oil) to the supply path (hydraulic circuit) is interrupted. The pallet P can be reliably prevented from falling off the table 10 even when the hydraulic pressure is down. In particular, even if the above situation occurs while the table is tilted during machining with a five-axis control machine tool like the MC according to this embodiment, the pallet P can be prevented from falling from the tilted table 10. can be effectively prevented. Moreover, by using the coil spring 206 as the biasing means, the pallet fall prevention device 200 can be configured simply and inexpensively.

INDUSTRIAL APPLICABILITY According to the present invention, there is provided a device capable of reliably preventing a pallet from falling off a table in a machine tool such as a machining center, and in particular, reliably preventing the pallet from falling even when the table is tilted in a 5-axis control machine tool or the like. It is possible to provide a device that can

In the above-described embodiments, the present invention is applied to a 5-axis control machining center having an APC and a pallet clamping mechanism, but it is of course not limited to this. As long as the present invention has a pallet clamping mechanism, the present invention can be applied to a machine tool whose table is maintained in a horizontal state, and a numerical control router (herein The router mentioned in (1) has a meaning close to a "hollowing machine") and can be widely applied to machine tools, etc.

10 table, 12 pedestal, 15 hydraulic oil supply path,
100 pallet clamping mechanism, 102 pallet support,
102A clamping cylinder chamber, 104 clamping piston,
106 bolt, 200 pallet fall prevention device, 202 fall prevention cylinder chamber,
204 drop prevention pin, 206 coil spring, 208, 209 port,
P Pallet, Ph Fall prevention insertion hole

Claims (2)

An automatic pallet changer and a clamping mechanism for clamping or unclamping the pallet on the table, the clamping mechanism having a clamping cylinder and a clamping piston within the clamping cylinder in response to the supply or flow of hydraulic fluid. In the pallet drop prevention device for machine tools that raises and lowers the pallet on the table by
a fall prevention cylinder provided further inside a clamping piston in the clamping cylinder, to which working fluid is supplied or discharged in a direction opposite to the supply or flow of working fluid to the clamping cylinder, and the fall prevention a drop-prevention pin provided in the drop-prevention cylinder that extends or retracts when working fluid is supplied or flowed into the drop-prevention cylinder; and biasing means that biases the drop-prevention pin to extend. , an insertion hole formed in a corresponding portion of the table mounting side surface of the pallet,
When the working fluid is supplied to the drop prevention cylinder, the drop prevention pin extends and is inserted into the insertion hole of the pallet, and when the supply of the working fluid to the drop prevention cylinder is stopped. is a pallet drop prevention device in which the drop prevention pin is extended by the urging force of the urging means to maintain the inserted state in the insertion hole, and when the pallet is unclamped, the pallet drop prevention device A pallet fall prevention device for a machine tool, wherein a pin follows the pallet. 2. The pallet fall prevention device according to claim 1, wherein said biasing means is a coil spring provided in said fall prevention cylinder and biasing the rear end of said fall prevention pin.

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