JP4345540B2 - Work support device - Google Patents

Description

  The present invention relates to a workpiece support device, and more particularly to a workpiece support device that supports a workpiece on a spindle that rotates the workpiece in a machine tool.

  In a machine tool such as a cylindrical grinder or a lathe, a workpiece is supported on a main shaft by a workpiece support device, and the workpiece is rotated by the main shaft to perform appropriate processing such as grinding or cutting. Here, the work support device includes a clamp device provided on the main shaft, and the work is fixed to the main shaft by gripping (chucking) its outer surface and inner surface in the radial direction by the clamp device. It supports the workpiece. And as a clamp apparatus, what is driven by fluid pressures, such as hydraulic pressure and an air pressure, is generally used.

  By the way, when the workpiece is fixed by the clamp device, if the fluid pressure that activates the clamp device drops due to stoppage of the fluid pressure source or pressure leakage in the fluid pressure path, the workpiece can be fixed by the clamp device. Therefore, there is a possibility that the workpiece may fall inadvertently from the workpiece support device. When the workpiece is accidentally dropped from the workpiece support device in this way, a cutting tool such as a grinding wheel or a bite collides with the workpiece, or a drive device of the machine tool collides with the workpiece, resulting in great damage to the entire machine tool. Sometimes.

  Therefore, in the conventional work support device, an accumulator is provided in the pressure path of the fluid that operates the clamp device, and even if the fluid pressure supplied to the clamp device drops due to an unexpected situation, the fluid pressure already supplied to the clamp device Can be compensated by the accumulator, and the work is prevented from being accidentally dropped from the work support device by opening the clamp device.

  The above background art is a general matter, and the applicant of the present application does not particularly know a document in which a description specifying the background art is made at the time of filing.

  However, even if an accumulator is provided as described above, pressure leakage cannot be eliminated and a predetermined fluid pressure cannot be maintained permanently. For this reason, in the conventional workpiece support device, the state in which the workpiece is fixed by the clamp device cannot be reliably maintained, and the workpiece cannot be prevented from being accidentally dropped.

  In particular, in the case where the clamping device is composed of a clamp base fixed to the spindle and a clamp arm that is tilted, when the workpiece is attached or detached, the workpiece should not be accidentally dropped by opening the clamping device. The rotation of the spindle is stopped in a state where the clamp base is positioned below the workpiece so that the workpiece is placed on the clamp base. However, in the case of an emergency stop due to an unexpected situation, when the clamp base is not located on the lower side of the workpiece and the clamp arm is located on the lower side of the workpiece, the workpiece load is applied to the clamp arm. Therefore, the fluid pressure that tilts and drives the clamp arm toward the fixed side of the workpiece is likely to decrease, and the clamp arm is likely to change to the open side, causing a problem that the workpiece falls from the workpiece support device.

  This invention is made | formed in view of the said actual condition, and makes it a subject to provide the workpiece support apparatus which can prevent reliably a workpiece | work falling by the fall of the fluid pressure which drives a clamp apparatus.

The main means taken by the present invention to solve the above problems are as follows:
“A work support device that is provided on a main shaft for rotationally driving a work and supports the work on the main shaft,
A clamping device driven by fluid pressure to fix or release the workpiece;
A workpiece support device comprising an opening prevention device that restricts the operation of the clamping device and prevents the clamping device from changing from a fixed side for fixing the workpiece to an opening side for releasing the workpiece.
It is.

  In the workpiece support device configured as described above, even if the fluid pressure that drives the clamp device decreases, the clamp device moves from the fixed side that fixes the workpiece to the open side that opens the workpiece by the release prevention device that restricts the operation of the clamp device. Fluctuation is prevented. For this reason, the work is released from the clamping device and does not fall, and is maintained in a state of being supported by the work support device. Further, the opening prevention device restricts the operation of the clamp device, in other words, mechanically restrains the movement of the clamp device. Therefore, prevention of the fluctuation | variation to the open side of the clamp apparatus by an opening prevention device is implement | achieved appropriately and reliably. Therefore, according to this work support device, it is possible to reliably prevent the work from dropping due to a decrease in fluid pressure that drives the clamp device.

In the means described above,
“The opening prevention device is urged so as to be in a restricting state that restricts the operation of the clamping device, and at least the opening prevention device is driven by the fluid pressure of the opening-side fluid pressure path that drives the clamping device to the opening side. A workpiece support device that is driven so as to be in an allowable state that allows the operation of the clamping device against its urging force "
It is good.

  In the clamping device, when the movement from the fixing side for fixing the workpiece to the opening side for releasing the workpiece is blocked by the opening blocking device, when the workpiece is attached to and detached from the workpiece support device, the operation of the clamping device by the opening blocking device is prevented. If the operation for releasing the regulation is not performed separately, the work cannot be released from the clamping device, which hinders the smooth work of attaching and detaching the work.

  On the other hand, in the workpiece support device having the above-described configuration, when at least the clamp device is driven to the open side, the release prevention device is also driven by the fluid pressure of the open side fluid pressure path that drives the clamp device to the open side. The blocking device is in an allowable state that allows the operation of the clamping device. For this reason, when attaching and detaching a workpiece to and from the workpiece support device, it is not necessary to separately operate the opening prevention device. Therefore, according to the workpiece support device having the above-described configuration, good workability can be ensured when the workpiece is attached to and detached from the workpiece support device.

  In addition, since the opening prevention device is biased to be in a restricted state that restricts the operation of the clamping device, in order to place the opening prevention device in a restricted state that restricts the operation of the clamping device, fluid pressure or electric Does not require power. Therefore, even if a power source such as a fluid pressure source or a power source is cut off as an unforeseen situation, the clamp device can be operated accurately and reliably so as not to open the workpiece.

In the means described above,
“The opening prevention device is in a permissible state in which the operation of the clamping device is allowed against the biasing force of the opening prevention device itself, even by the fluid pressure in the fixed fluid pressure path that drives the clamping device to the fixed side. Work support device characterized by being driven like this "
It is good.

  In the workpiece support device having the above configuration, the clamp device is driven to the open side by the fluid pressure of the open side fluid pressure path, and the state of being driven to the fixed side by the fluid pressure of the fixed side fluid pressure path. In both states, the opening prevention device is in an allowable state in which the operation of the clamping device is allowed. Here, when the machine tool is in operation, the clamp device is always driven to the open side for releasing the workpiece or driven to the fixed side for fixing the workpiece. , Always in an acceptable state. The opening prevention device operates so as to be in a restricted state when the fluid pressures in both the opening side fluid pressure path and the fixed side fluid pressure path are lowered. This is because the output of the fluid pressure source is reduced. It is an emergency when it drops or leaks in the pressure path.

  By the way, when the clamp device is driven to the fixed side, the above-described state of the clamp device is maintained unless the fluid pressure in the fixed-side fluid pressure path is lowered. The workpiece supported by the workpiece support device does not fall unintentionally. Therefore, in this case, no inconvenience occurs even if the opening prevention device is in the permitted state. On the other hand, if the clamping device is inadvertently moved to the open side and the workpiece supported by the workpiece supporting device falls, the problem is that the fluid pressure in the fixed fluid pressure path decreases and the clamping It is an emergency when the device can no longer be maintained driven to the fixed side. In this emergency, in the work support device having the above-described configuration, the release preventing device is in a restricted state, and the fluctuation of the clamp device to the open side is restricted to prevent the work from falling from the work support device. That is, in the workpiece support device having the above-described configuration, the opening prevention device functions as a so-called “safety device” that does not operate so as to be in a restricted state during normal times but operates so as to be in a restricted state in an emergency. Therefore, in the work support device having the above-described configuration, the opening prevention device does not have any influence on the work support device and the entire machine tool at normal times, thereby reducing the usability of the work support device and the entire machine tool. I will not let you.

In the means described above,
“The clamp device includes a clamp base fixed to the main shaft, a tilt arm supported by the main shaft so as to be tiltable, and a clamp arm that grips the workpiece in the radial direction with the clamp base, and an arm drive that tilts the clamp arm. Having a device,
The opening prevention device is supported by the main shaft so as to be able to advance and retreat, and in a state of being advanced, a stopper pin that contacts the clamp arm in a state of gripping a workpiece and restricts the operation of the clamp arm, and drives the stopper pin forward and backward Workpiece support device characterized by having a pin drive device "
It is good.

  The workpiece support device having the above configuration specifically limits the structures of the clamp device and the release prevention device. According to this work support device, even if the fluid pressure that drives the clamp device is reduced, a mechanism that can reliably prevent the work from falling can be reliably realized with a simple structure. Further, in the clamp device having the clamp base and the clamp arm, as described above, the clamp device is likely to move to the open side depending on the stop position of the main shaft, and the work is likely to be accidentally dropped. Therefore, it is preferable to provide an opening prevention device in the workpiece support device having such a clamping device so as to reliably prevent the workpiece from being accidentally dropped.

  As described above, according to the work support device of the present invention, it is possible to reliably prevent the work from dropping due to a decrease in fluid pressure that drives the clamp device.

  Next, an embodiment of a workpiece support device according to the present invention will be described in detail with reference to the drawings.

  1 and 2 show an example of a workpiece support device 20 according to the present invention provided in a cylindrical grinding machine. This work support device 10 is provided on the front surface of a chuck 12 mounted on a spindle 11 of a spindle stock 10 of a cylindrical grinding machine. The cylindrical grinding machine of this example uses the crankshaft as the workpiece W and grinds the outer peripheral surface of the crankpin W2. The crank journal W1 that is the end of the workpiece W is eccentric from the rotation center of the main shaft 11. The workpiece support device 20 supports the part. Furthermore, in this example, the two headstocks 10 are disposed opposite to each other on the upper surface of a work table (not shown) that supports the work W, and both ends of the work W are supported by the headstocks 10 and both ends. A rotational force is applied to the part and the part is driven to rotate.

  Although illustration is omitted, the cylindrical grinding machine does not include the two headstocks 10, but the workpieces follow the rotational drive of the headstock 10 on one side of the work table and the headstock 10 on the other side. In order to rotate W, it is provided with a rotation support base such as a tailstock that rotatably supports the work W, and the rotation support base also has a work support device that supports the work W. In this case, the work support device 20 according to the present invention may be employed as at least one work support device on the head stock 10 side or the rotation support base side. Here, on the rotation support base side, the member on which the work support device 20 is provided has the same meaning as the main spindle 11 of the head stock 10. In other words, in the present invention, the member on which the workpiece support device 20 is provided, including the member on the rotation support base side, is defined as the “main shaft 11”.

  The workpiece support device 20 includes a clamp device 30 that is driven to fix or release the workpiece W. The clamp device 30 includes a clamp base 60 fixed to the chuck 12 of the main shaft 11, a clamp arm 40 that is supported by the main shaft 11 so as to be tiltable, and holds the workpiece W in the radial direction with the clamp base 60, The clamp arm 40 is configured to have an arm driving device 50 that tilts and drives.

  The clamp base 60 includes a reference block 61 that abuts substantially half of the outer peripheral surface of the work W, and a spacer 62 that finely adjusts the position of the reference block 61 in the height direction and the width direction. The reference block 61 and the spacer 62 are accurately positioned with respect to the main shaft 11.

  The clamp arm 40 is rotatably supported on the main shaft 11 by a support shaft 41 at a substantially central portion, and tilts between a state in which the workpiece W is fixed by the clamp base 60 and a state in which the workpiece W is released. Also, a clamp 44 is attached to one end of the clamp arm 40, and the workpiece W is fixed by abutting and pressing the clamp 44 against the workpiece. Further, a long hole 43 is provided on the other end side of the clamp arm 40.

  The arm drive device 50 is configured by using a fluid pressure cylinder that is operated by fluid pressure such as hydraulic pressure or air pressure. The arm drive device 50 includes a cylinder body 51 and a forward / backward shaft 53 that protrudes from the cylinder body 51. A piston 52 is provided that is reciprocally incorporated and divides the inside of the cylinder body 51 into a first cylinder chamber 51a and a second cylinder chamber 51b. Further, the distal end portion of the advance / retreat shaft 53 is connected to the elongated hole 43 of the clamp arm 40 via a connection pin 54.

  When fluid pressure is supplied from the fixed-side fluid pressure path A to the first cylinder chamber 51a of the arm drive device 50, the piston 52 moves so that the volume of the first cylinder chamber 51a increases, and the advance / retreat shaft 53 moves forward. To do. The clamp arm 40 is pushed by the advancement of the advance / retreat shaft 53, and the clamp arm 40 tilts to the side on which the workpiece W is fixed, that is, the “fixed side”, and fixes the workpiece W. On the other hand, when fluid pressure is supplied from the open-side fluid pressure path B to the second cylinder chamber 51b, the piston 52 moves so that the volume of the second cylinder chamber 51b increases as shown by a two-dot chain line in FIG. Then, the advance / retreat shaft 53 moves backward. The clamp arm 40 is pulled by the retreat of the advance / retreat shaft 53, and the clamp arm 40 tilts to the side that opens the workpiece W, that is, the “open side”, and opens the workpiece W.

  In addition, the workpiece support device 20 includes an opening prevention device 70 that prevents the clamping device 30 from changing from a fixing side that fixes the workpiece W to an opening side that opens the workpiece W. Specifically, the opening prevention device 70 has a stopper pin 75 that is supported by the chuck 12 of the main shaft 11 so as to freely advance and retract. When the stopper pin 75 moves forward as indicated by a two-dot chain line in FIG. The stopper pin 75 comes into contact with the clamp arm 40 and restricts the operation of the clamp arm 40 toward the open side. In other words, the clamp arm 40 is restrained at the operation position where the clamp arm 40 fixes the workpiece W. This prevents the clamping device 30 from inadvertently opening the workpiece W, and prevents the workpiece W from dropping from the workpiece support device 20.

  Since the workpiece W can be prevented from falling off by preventing the clamp arm 40 from tilting greatly toward the open side, the stopper pin 75 must be in close contact with the clamp arm 40 when the stopper pin 75 is advanced. There is no. Therefore, in this example, an appropriate interval is secured between the stopper pin 75 and the clamp arm 40. As a result, even if there is a difference in the position of the clamp arm due to the wear of the abutment 44 of the clamp arm 40 or the dimensional error of the workpiece W, the stopper pin 75 is advanced and retracted satisfactorily without interfering with the clamp arm 40. be able to. Even if there is a difference in the position of the clamp arm 40 by providing a tapered surface at the tip portion of the stopper pin 75 or making the tip portion of the stopper pin 75 an elastic structure made of rubber, a spring or the like, the stopper pin You may make it 75 contact | abut to the crank arm 40 reliably. Furthermore, the stopper pin 75 is not limited to the one that abuts against the end face of the clamp arm 40 and restricts the operation of the clamp arm 40, but the one that abuts against a variable member other than the clamp arm 40 to restrict the operation, It may be engaged with the pin hole of the clamp arm 40 or other member to restrict its operation.

  Next, details of the opening prevention device 70 will be described with reference to FIG. The opening prevention device 70 is configured using a fluid pressure cylinder that is operated by fluid pressure in fluid pressure paths A and B connected to an arm drive device 50 that drives the clamp device 30. The opening prevention device 70 has a cylinder body 73 and a stopper pin 75 protruding from the cylinder body 73. The first piston 71 reciprocally incorporated in the cylinder body 73 and the direction in which the stopper pin 75 moves forward. And an urging member 74 configured by a compression coil spring or the like for urging the first piston 71 and a cylinder main body 73 so as to reciprocate, and the inside of the cylinder main body 73 is arranged in a first cylinder chamber 73a on the first piston 71 side. And the 2nd piston 72 divided in the 2nd cylinder chamber 73b on the opposite side to the 1st piston 71 is provided.

  Here, to the first cylinder chamber 73a of the cylinder body 73, the fixed-side fluid pressure path A connected to the first cylinder chamber 51a of the arm driving device 50 described above is connected. When fluid pressure is supplied to the arm drive device 50 from the fixed-side fluid pressure path A and the clamp device 30 is driven to the fixed side, the opening blocking device 70 increases the volume of the first cylinder chamber 73a accordingly. Thus, the first piston 71 moves to retract the stopper pin 75. Therefore, in this state, the opening prevention measure 70 is in an allowable state in which the operation of the clamping device 30 is allowed. Although illustration is omitted, in this state, since the volume of the first cylinder chamber 73a increases, the first piston 71 moves backward and the second piston 72 moves forward.

  An open-side fluid pressure path B connected to the second cylinder chamber 51 b of the arm drive device 50 is connected to the second cylinder chamber 73 b of the cylinder body 73. When the fluid pressure is supplied to the arm driving device 50 from the opening-side fluid pressure path B and the clamp device 30 is driven to the opening side, the volume of the second cylinder chamber 73b increases in the opening preventing device 70 accordingly. Thus, the second piston 72 moves. At this time, the second piston 72 comes into contact with the first piston 71, presses and moves the first piston 71, and retracts the stopper pin 75. Therefore, even in this state, the opening prevention measure 70 is in an allowable state in which the operation of the clamping device 30 is allowed.

  By the way, the state in which the fluid pressure applied to both the first cylinder chamber 73a and the second cylinder chamber 73b of the cylinder body 73 is reduced is due to some situation in both the fixed-side fluid pressure path A and the open-side fluid pressure path B. This is an emergency when the fluid pressure is reduced. In such a state, in the opening prevention device 70, the driving by the fluid pressure described above is stopped, the first piston 71 is advanced by the urging force of the urging member 74, and the stopper pin 75 is advanced. As a result, the opening prevention device 70 enters a restricted state in which the operation of the clamp device 30 is restricted. The cylinder body 73 is provided with an air vent hole 76 that allows the space on the rear end side of the first piston 71 inside the cylinder body 73 to communicate with the outside air. The space on the rear end side of the first piston 71 is Since the air is released to the atmosphere, the reciprocating movement of the first piston 71 is performed smoothly.

  As described above, in the work support device 20 of the present example, the opening prevention device 70 is allowed in a normal state and does not cause any trouble when the work W is attached or detached. The blocking device 70 is in a restricted state, and the clamping device 30 is reliably blocked from moving to the open side, and the work W is prevented from being accidentally dropped. In addition, even if the fluid pressure paths A and B connected to the first cylinder chamber 73a and the second cylinder chamber 73b of the cylinder body 73 of the opening prevention device 70 are set in the opposite direction, the same operation can be obtained. Can do. Further, a fluid pressure path separate from the fluid pressure paths A and B of the clamping device 30 is connected to the opening prevention device 70 so that the opening prevention device 70 is driven separately from the driving of the clamping device 30. Also good.

  In the above, an example of the workpiece support device according to the present invention has been described. However, the workpiece support device according to the present invention is not limited thereto, and various modifications can be made without departing from the gist of the present invention.

  For example, the clamping device is not limited to one that employs a tilt arm that drives tilting, but may be one that employs a clamping member that is driven in an appropriate manner, such as raising / lowering driving or forward / backward driving. Further, the opening prevention device is not limited to the one using a fluid pressure cylinder driven by fluid pressure, but may be one using a solenoid driven by electric power. Also in this case, it is preferable that the opening prevention device itself is urged to the restricted state so that the open state is allowed by supplying the power source and the restricted state is caused by cutting the power source. Further, in the opening prevention device, as a member for restricting the operation of the clamp device, a stopper member that operates in an appropriate manner such as tilting and sliding can be adopted in addition to a stopper pin that moves forward and backward. Furthermore, the workpiece support device according to the present invention is not limited to a cylindrical grinding machine, and can be applied to a wide range of machine tools that support and rotate a workpiece during machining, such as a lathe.

It is a front view which shows an example of the workpiece | work support apparatus which concerns on this invention. It is a side view of the workpiece | work support apparatus shown in FIG. It is a sectional side view showing an example of an opening prevention device.

Explanation of symbols

W Work (Crankshaft)
W1 Crank journal W2 Crank pin 10 Main shaft base 11 Main shaft 12 Chuck 20 Work support device 30 Clamp device 40 Clamp arm 41 Support shaft 43 Long hole 44 Metal 50 Arm drive device 51 Cylinder body 51a First cylinder chamber 52b Second cylinder chamber 52 Piston 53 Advancing and retracting shaft 54 Connecting pin 60 Clamp base 61 Reference block 62 Spacer 70 Opening prevention device 71 First piston 72 Second piston 73 Cylinder body 73a First cylinder chamber 73b Second cylinder chamber 74 Energizing member 75 Stopper pin 76 Air vent Hole

Claims (3)

A work support device provided on a main shaft for rotationally driving the work, and supporting the work on the main shaft;
A clamping device driven by fluid pressure to fix or release the workpiece;
An opening prevention device that regulates the operation of the clamping device and prevents the clamping device from changing from a fixing side for fixing the workpiece to an opening side for releasing the workpiece ;
The opening prevention device is biased so as to be in a restricting state for restricting the operation of the clamping device, and at least the opening prevention device itself by the fluid pressure of the opening side hydraulic pressure path that drives the clamping device to the opening side. A workpiece support device that is driven so as to be in an allowable state in which the operation of the clamp device is allowed against the urging force of . The opening prevention device is allowed to operate in a clamping device against the urging force of the opening prevention device itself even by a fluid pressure in a fixed fluid pressure path that drives the clamping device to a fixed side. The workpiece support device according to claim 1, wherein the workpiece support device is driven by a motor. The clamp device includes a clamp base fixed to a main shaft, a tilt arm supported by the main shaft so as to be tiltable, and a clamp arm that grips the workpiece in a radial direction with the clamp base, and an arm driving device that tilts and drives the clamp arm. And having
The opening prevention device is supported by the main shaft so as to be able to advance and retreat, and in a state of being advanced, a stopper pin that contacts the clamp arm in a state of gripping a workpiece and restricts the operation of the clamp arm, and drives the stopper pin forward and backward The work support apparatus according to claim 1 or 2 , further comprising a pin driving device.

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