JPH0760515A - Tool attaching/detaching device - Google Patents

Abstract

PURPOSE:To provide a tool attaching/detaching device with which effects of hysteresis characteristics in a clamp spring can be avoided, with which deflection quantity at the time of clamping can therefore be reduced, with which operation force at the time of unclamping can be reduced, with which deflection quantity per spring can be set smaller, and with which life of the spring can be elongated. CONSTITUTION:A tool attaching/detaching device is provided with a draw bar 37 inserted into a spindle hole of a main spindle 32 to be freely movable in the axial direction of the main spindle 32 for clamping/unclamping a tool T to/from a tool installation hole 32c of the main spindle 32 by axial movement, a clamp spring 43 to energize the draw bar 37 in the clamping direction, and a clamping/unclamping operation mechanism 70 to perform clamping action in a process where deflection quantity of the clamp spring 43 is increased, and perform unclamping action in a process where the deflection quantity is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tool attaching / detaching device for clamping / unclamping a tool on a spindle of an angular attachment (hereinafter abbreviated as attachment) mounted on the tip of a spindle ram, and more specifically, a necessary clamp. The present invention relates to improvement of a clamp / unclamp method that can secure force with a small amount of deflection.

[0002]

2. Description of the Related Art For example, in a machine tool such as a five-sided machine, an attachment is attached to the tip of a spindle ram so that the attachment can be pivotally indexed and detached, and a tool is attached to the tip of the spindle by an automatic tool changer. Some of them are automatically replaced and mounted one after another for processing. Such a machine tool is provided with a tool attaching / detaching device that automatically clamps / unclamps the tool at the time of replacement.

As such a tool attaching / detaching device, there is one conventionally disclosed, for example, in Japanese Patent Publication No. 61-57138. This is configured as shown in FIG. 11, for example. A tapered hole 102a is formed at the tip of a hollow main shaft 102 that is rotatably supported on the attachment body 100 via a bearing 101, and the tapered portion Ta of the tool T is inserted into the tapered hole 102a. Then, the collet 103 is engaged with and disengaged from the pull stud Tb of the tool T by the drawbar 104, and the drawbar 104 is clamped by the disc spring 105.
It is configured to be pulled in the clamp direction. Further, behind the drawbar 104, the drawbar 104
A hydraulic cylinder 107 that pushes and moves the piston is provided.

To unclamp the tool T in the above conventional apparatus, the hydraulic cylinder 107 is connected to the drawbar 10.
Move forward to press 4. Then piston rod 1
06 pushes and advances the draw bar 104 against the spring force of the disc spring 105 until the collet 103 is completely opened, the collet 103 is disengaged from the pull stud Tb, and the tip of the draw bar 104 is brought to the rear end surface of the pull stud Tb. When it hits, the close contact between the tool T and the tapered hole 102a is released. After that, the tool T is pulled out by a tool changer or the like.

To clamp the tool T, the tool T is inserted into the tapered hole 102a by a tool exchanging device or the like, and the hydraulic cylinder 107 is retracted. Then drawbar 104
Is moved backward by the disc spring 105 and collet 1
03 is contracted and pulled inward of the spindle, whereby the tool T is clamped to the spindle 102.

[0006]

SUMMARY OF THE INVENTION Here, the inventor of the present invention discloses a case in which a large number of disc springs are coaxially arranged, gradually compressed, and after a predetermined deflection, the compression force is gradually released. The relationship between the amount of flexure and the spring force generated was investigated, and as shown in FIG. 12, the spring force (characteristic line A) generated during the flexure increase process and the spring force (characteristic line B) generated during the flexure decrease process. We paid attention to the existence of hysteresis between the two.

The present inventor has found that the above conventional device has the following problems. That is, in the above conventional device, the unclamping is performed in the state of the maximum deflection amount E1 in the deflection increasing process, and the deflection amount E2 in the deflection decreasing process is performed.
I am trying to clamp in the state of. Therefore, the spring force P2 generated in this clamped state is smaller than the spring force P2 'generated at the same deflection amount E2 in the deflection increasing process. In other words, there is no choice but to set the flexure amount E2 larger than the flexure amount E3 for generating the spring force P2 in the process of increasing the flexure.

Further, in the above-mentioned conventional apparatus, it is necessary to secure the maximum deflection amount E1 (collet opening stroke) so that the collet is completely opened at the time of unclamping. Therefore, the total length of the clamp spring becomes long, so that the tool attaching / detaching device can be installed. There is a problem that the built-in spindle length becomes long. When unclamping the clamp spring, the maximum deflection E1
There is also a problem that the operation force during unclamping becomes extremely large because it is necessary to compress up to.

The present invention has been made in view of the above-mentioned conventional problems, and it is possible to avoid the influence of the hysteresis characteristic of the clamp spring, and therefore, it is possible to reduce the amount of deflection at the time of clamping, and at the time of unclamping. It is an object of the present invention to provide a tool attaching / detaching device that can reduce the operating force, can further set the amount of deflection per spring to be small, and can extend the life of the spring.

[0010]

According to a first aspect of the present invention, there is provided a drawbar which is movably inserted in a shaft hole of a main shaft in a direction of a main shaft axis, and clamps / unclamps a tool in a tool mounting hole of the main shaft by the axial movement. A clamp spring for urging the draw bar in the clamp direction, and a clamp / unclamp operation mechanism for performing a clamp operation in the process of increasing the amount of deflection of the clamp spring and an unclamping process in the process of decreasing the amount of deflection. Is a tool attaching / detaching device.

According to the second aspect of the present invention, a clamp operating mechanism is provided for performing a clamping operation by compressing the spring force or the amount of deflection during clamping to be larger than the spring force or the amount of deflection during unclamping. I am trying.

[0012]

According to the tool attaching / detaching device of the invention of claim 1,
With the clamp / unclamp operation mechanism, the tool clamping operation is performed in the process of increasing the deflection amount due to the increase of the compression force applied to the clamp spring, and the tool unclamping operation is performed in the process of the deflection amount decreasing due to the decrease of the compression force. Done. According to the second aspect of the present invention, the clamp operation mechanism performs the clamping operation such that the spring force or the flexure amount during the clamping is larger than the spring force or the flexure amount during the unclamping.

Therefore, in the device of the present invention, in FIG. 10, for example, when the required clamping force P2 is obtained, the deflection amount is E3 as compared with the conventional E2, and the deflection amount of the clamp spring is reduced while securing the required clamping force P2. it can. Further, in the device of the present invention, since the spring force and the amount of deflection at the time of unclamping are smaller than those at the time of clamping, the operating force at the time of unclamping can be reduced, and the amount of deflection can be made smaller.
The amount of deflection per sheet can be set small, and the life of the spring can be extended.

[0014]

Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 to 10 are views for explaining a tool attaching / detaching device according to an embodiment of the present invention, FIG. 1 is a sectional front view of a 90-degree angular attachment including the tool attaching / detaching device of the present embodiment, and FIG. 2 is the attachment. FIG. 3 is a sectional view taken along the line III-III of FIG. 2, FIG. 4 is an enlarged exploded perspective view of the main portion, and FIGS. 5 to 8 are views for explaining the operation of the attachment. Is a partial sectional front view of a spindle ram equipped with the above attachment, and FIG. 10 is a flexure-spring force characteristic diagram for explaining the effect of this embodiment.

In each of the above figures, 1 is a spindle ram,
The main spindle ram 1 includes a cylindrical ram body 2, a rotary drive motor 3 arranged and fixed coaxially with the ram body 2,
A drive shaft 5 inserted into the output shaft 4 of the rotary drive motor 3 so as to rotate together with the output shaft 4 and to be movable in the axial direction.
And a shaft feed mechanism 6 attached to the upper end of the main spindle ram body 2 for moving the drive shaft 5 in the axial direction, and a disengagement mechanism for clamping / unclamping a pressing shaft 33 of an attachment 8 described later on the drive shaft 5. A mechanism 7 and an attachment / detachment mechanism 22 disposed on the inner surface of the lower portion of the ram body 2 for detachably attaching the attachment 8 to the lower end portion of the ram body 2 are provided. The feed mechanism 6 and the engagement / disengagement mechanism 7 constitute a drive source of the tool attaching / detaching device of this embodiment, and the attachment 8 constitutes an operating portion of the tool attaching / detaching device of this embodiment.

The rotary drive motor 3 has a motor case 9
The output shaft 4 is rotatably disposed inside a bearing 10, and the rotor 11 and the stator 12 are disposed so as to face each other between the output shaft 4 and the motor case 9.

In the shaft feed mechanism 6, a rotary cylinder 14 is rotatably disposed on the upper end of the ram body 2 via a bearing 13, and the rotary cylinder 14 is driven by a drive motor 15 to form pulleys 16a, 1a.
6b, and is driven to rotate via the belt 17. Further, a nut member 18 is fixed inside the rotary cylinder 14, and a ball screw 19 is screwed into the nut member 18. To the lower end of the ball screw 19, a connecting cylinder 20 is inserted which is inserted into the boss portion 9a of the motor case 9 so as to be movable in the axial direction. The connecting cylinder 20 is connected to the ball screw 19 and the drive shaft 5. Is connected to the upper end of the through a bearing 21. Further, the tapered portion 33a of the pressing shaft 33 of the attachment 8 is fitted in the tapered hole formed at the lower end of the drive shaft 5, so that when the ball screw 19 is moved up and down, the pressing shaft 33 moves up and down. It has become.

The engaging / disengaging mechanism 7 has a piston rod 26 in a cylinder 25 fixed to the upper end of the ball screw 19.
The piston 26a is inserted, and the piston rod 26 is inserted through the axial center of the ball screw 19 so as to be movable in the axial direction. The lower end portion of the piston rod 26 is a draw bar 27 inserted in the drive shaft 5 so as to be movable in the axial direction.
The drawbar 27 is disposed so as to be capable of contacting the upper end of the drawbar 27.
Is urged upward by a clamp disc spring 28. Further, at the lower end portion of the draw bar 27, a collet 29 that engages and disengages with the pull stud of the pressing shaft 33 of the attachment 8 is attached.
The collet 29 expands and contracts when the draw bar 27 is moved up and down.

The attaching / detaching mechanism 22 has a piston 23 disposed in a cylinder 2a coaxially formed in the ram body 2 and a plurality of collets arranged circumferentially at the lower end of the piston 23. The collet chuck 24 is configured to move up and down. When the piston 23 is moved up and down, the collet chuck 24 is disengaged from the flange portion 30a of the attachment case 30 of the attachment 8 and is fixed to the attachment case 30 and the ram body 2 respectively.
b and 2b are disengaged from each other.

The attachment 8 has an intermediate shaft 31 in a vertical direction inside the attachment case 30 having a substantially L-shaped shape, and a main shaft 32 in a horizontal direction orthogonal to the intermediate shaft 31.
And rotatably supported by bearings 31a and 32a, respectively. The intermediate shaft 31, the main shaft 32
Is connected by meshing the bevel gears 31b and 32b,
The rotation of the intermediate shaft 31 around CT1 is transmitted as the rotation of the main shaft 32 around CT2.

An annular coupling 30b, which meshes with the coupling 2b provided on the lower end surface of the ram body 2 and is positioned at a predetermined angle around the axis of the drive shaft, is fixed to the attachment case 30. Further, a flange portion 30a is formed on the upper end of the cylindrical convex portion that penetrates the coupling 30b and projects upward, to engage and disengage the collet chuck 24 of the attachment / detachment mechanism 22.

The intermediate shaft 31 has a cylindrical shape into which the drive shaft 5 is inserted. An inner gear 31c is formed on an inner peripheral surface of an upper end portion of the drive shaft 5 protruding upward from the attachment case 30. Is meshed with an external gear formed on the lower outer peripheral surface of the shaft so as to be rotatable and relatively movable in the axial direction. Further, the pressing shaft 33 is inserted into the intermediate shaft 31 so as to be movable in the axial direction and urged upward by a spring 34. A compression shaft portion 33b for pressing and rotating a cam described later is formed at the lower end of the pressing shaft 33.

The main shaft 32 has a cylindrical shape, and a taper hole 32c for fitting with the taper portion of the tool T is formed at the tip (right end in FIG. 1) of the main shaft 32, and the shaft hole connected to the taper hole 32c is formed in the shaft hole. A guide cylinder 35 is fitted concentrically with the main shaft 32. Inside the guide cylinder 35, there are arranged a collet chuck 36 which is formed by combining a plurality of collets on the circumference and is movable in the axial direction, and a draw bar 37 which locks the collet chuck 36 and drives the collet chuck 36 to move in the axial direction. It is set up.

The collet chuck 36 is constructed so as to be expanded and contracted in the radial direction by being guided by the guide surface inside the guide cylinder 35 by a slight movement in the axial direction. The drawbar 37 is attached to the spring 4 via an operation mechanism 70 described later.
When the main shaft 32 is biased rearward (leftward in FIG. 1) by the spring force of 3, the collet chuck 36 holds the pull stud Tp fixed to the tip of the taper portion of the tool T and the main shaft 3
2 Pull it in the rearward direction and insert the tool T into the main shaft tapered hole 3
Clamp to 2c.

The operating mechanism 70 has the following structure. A pressure rod 72 is inserted and arranged in the sleeve 71 inserted and fixed in the main shaft 32 so as to face the draw bar 37. The rear end flange portion 72 of the pressure rod 72
The clamp spring 43 is interposed between a and the bottom wall 71a of the sleeve 71.
Is urged to the rear of the spindle (to the left in FIG. 1). Opposing flanges 72c and 37b are formed on the opposing ends of the pressure rod 72 and the draw bar 37, respectively, and the first and second driven parts are provided on the opposite opposing surface sides of the opposing flanges 72c and 37b, respectively. Cam surfaces 72b and 37a are formed.

The sleeve 7 in the shaft hole of the main shaft 32.
1, a cylindrical sleeve 73 is axially movable and non-rotatably inserted between the guide cylinders 35, and an interrupting cam 74 is inserted in the sleeve 73 in a direction perpendicular to the main axis (vertical direction in FIG. 2). ) Is arranged so as to be movable. The intermittent cam 74 is formed by integrally forming semi-circular ring-shaped semi-circular flange portions 74b and 74c on both sides of the circular flange portion 74a with a space therebetween. The semi-circular flange portions 74b, 74c
Is formed with a semi-circular recess 74h in which the pressure rod 72 and the draw bar 37 are located, and the axially inner side surface (the surface facing the circular flange portion 74a) has the first and second portions. First and second drive cam surfaces 74d and 74e which are in sliding contact with the driven cam surfaces 72b and 37a are formed.
Here, the second drive cam surface 74e on the draw bar 37 side is lower than the first drive cam surface 74d on the pressure rod 72 side, and when the interrupting cam 74 moves in the direction perpendicular to the main axis, the second driven cam surface 74e. Comes off the second drive cam surface 37a,
This allows the draw bar 37 to move in the axial direction.

A projection 74i is provided on the surface of the circular flange portion 74a of the connecting / disconnecting cam 74 on the side of the draw bar, and the projection 74i is slidably guided on the outer end surface of the opposing flange portion 37b of the draw bar 37. Guide groove 37
c is formed. An inclined surface 37d is formed at the lower end of the guide groove 37c, and the inclined surface 37d is formed.
When the projection 74i presses, the draw bar 37 moves in the minute distance axial direction toward the unclamp side.

A clearance portion 73c is formed on the inner surface of the sleeve 73 that encloses the interrupting cam 74 so as to allow the interrupting cam 74 to move in the direction perpendicular to the axis. Further, a pair of guide pins 75 are fixed to the outer circumference of the circular flange portion 74a, and each guide pin 75 has a pair of guide holes 73 formed in the sleeve 73 in a direction perpendicular to the axis.
a, 73b. As a result, the connecting / disconnecting cam 74 is movable in the direction perpendicular to the main axis. Operation holes 32e and 32f are formed through the main shaft 32 so as to be coaxial with the guide holes 73a and 73b, and the pressing shaft 3 inserted through the operation holes 32e and 32f.
3, the intermittent cam 74 is moved in the direction perpendicular to the axis. Furthermore, the intermittent cam 74 described above
Is urged to the clamp position (the position shown in FIG. 2) by a spring 76 arranged between the sleeve 73 and a recess 74f formed in parallel with the guide holes 73a and 73b on the outer periphery thereof.

Next, the function and effect of this embodiment will be described. In the clamped state of the tool T, as shown in FIG. 5, the intermittent cam 74 is located at the clamp position at the upper end of the figure. Therefore, the first and second drive cam surfaces 74d and 74e of the intermittent cam 74 strongly slide against the pressure rod 72 and the first and second driven cam surfaces 72b and 37a of the draw bar 37, respectively, and the pressure rod 72, And the draw bar 37 is pulled inward, whereby the clamp spring 43 is compressed and its spring force is transmitted to the draw bar 37, and the collet chuck 36 holds the pull stud Tp of the tool T and pulls it inward. The resulting tool T is clamped in the tapered hole 32c of the spindle 32.

To unclamp the above tool T, refer to FIG.
As shown in, the pressing shaft 33 is inserted into the operation hole 32e and the disconnecting cam 74 is pushed down to the recess 73c side of the sleeve 73. Then, the first drive cam surface 74d and the first driven cam surface 7
The sliding contact force with 2b becomes weaker, and as a result, the pressure rod 7
2 moves a slight distance to the left in the drawing, and the second drive cam surface 74e
The second driven cam surface 37a is disengaged, the spring force of the spring 43 is cut off from the draw bar 37, and the draw bar 37 is allowed to move in the axial direction (to the right in the drawing).

When the intermittent cam 74 descends to a position where it comes into contact with the recess 73c, the projection 7 of the intermittent cam 74 is moved.
4i is an inclined surface 73d of the guide groove 37c of the drawbar 37.
The draw bar 37 is moved to the tool side in the axial direction by a minute distance, and the close contact with the taper hole 32c of the tool T is released (see FIG. 7). At this time, since the tool T is gripped by the tool changing arm, it does not drop.

Thereafter, when the tool T is moved in the pull-out direction (right direction in the drawing) by the tool exchanging arm, the collet chuck 36 moves together with the draw bar 37, the collet chuck 36 is opened, and the tool T can be pulled out. .

When the tool T of the next stroke is clamped, the tool T of the next stroke is inserted with the collet chuck 36 opened, and the pressing shaft 33 is once pulled out from the operation hole 32e, and then, as shown in FIGS. The main shaft 32 is rotationally positioned so that the operation hole 32f located on the lower side of the position coincides with the pressing shaft 33. The draw bar 37 is pushed inward by the pull stud Tp of the tool T, the collet chuck 36 is closed, and the pull stud Tp is gripped.
It will be in the same state as. After that, as shown in FIG. 8, the pressing shaft 33 is inserted through the operation hole 32f and the disconnecting cam 74 is pushed downward. Then, the first and second drive cam surfaces 74d,
74e slidably contacts the first and second driven cam surfaces 72b and 37a to draw the pressure rod 72 and draw bar 37 inward,
The spring force of the spring 43 is transmitted to the draw bar 37, and the tool T
Is clamped on the main shaft 32.

Spring 43 at the time of clamping / unclamping
The relationship between the flexure amount and the spring force (clamping force) will be described in more detail mainly with reference to FIG. In the figure, characteristic lines A and B are diagrams showing the clamping and unclamping operation in the conventional device, and characteristic lines A'and B'are diagrams showing the clamping and unclamping operation in the device of the present embodiment.

First, when the interrupting cam 74 is moved downward in FIG. 8 to clamp the tool, the pressure rods 72, 72 are moved by sliding contact between the driving cam surfaces and the driven cam surfaces as described above.
The draw bar 37 is pulled in, and the compressive force applied to the spring 43 by the pressure rod 72 increases. With the increase, the amount of deflection of the spring 43 and the spring force increase along the curve A'in FIG. Then, when the intermittent cam 74 moves to the clamp position at the lowermost end in FIG. 8, the amount of deflection of the spring 43 becomes E3, and the spring force becomes the necessary clamping force P2. As described above, in the apparatus of this embodiment, clamping is performed in the process of increasing the amount of spring deflection.

Next, when the interrupting cam 74 is moved downward in FIG. 5 to unclamp the tool, the sliding contact force between the cam surfaces weakens as described above, and the compression force by the pressure rod 72 decreases. Along with this, the amount of deflection of the spring 43 and the spring force decrease along the curve B'of FIG. When the intermittent cam 74 moves to the lowest unclamp position shown in FIG. 6, the amount of deflection of the spring 43 becomes E4, and the spring force becomes the spring force P4 during unclamping. As described above, in the apparatus of this embodiment, unclamping is performed in the process of reducing the amount of spring deflection.

As described above, in this embodiment, the clamping operation is performed in the process of increasing the deflection amount of the clamping spring 43, and the unclamping operation is performed in the process of decreasing the deflection amount. The amount of deflection when obtaining P2 is E3 as compared with the conventional E2, and the amount of deflection of the clamp spring 43 can be reduced while securing the required clamping force P2.

Further, in this embodiment, the spring force P4 and the deflection amount E4 at the time of unclamping are smaller than those at the time of clamping, so that the operating force at the time of unclamping, that is, the driving force of the pressing shaft 33 can be reduced. Further, since the amount of deflection per disc spring can be set small, the spring life can be extended.

In the above embodiment, an example in which a collet chuck is used as the clamping means for the tool T has been described.
The clamping means of the present invention is not limited to this. In short, any structure may be used as long as it is clamped by using a spring force, and for example, a ball lock may be used for clamping.

[0040]

As described above, according to the tool attaching / detaching device of the present invention, the spring is clamped in the process of increasing the deflection amount and unclamped in the process of decreasing the deflection amount.
There is an effect that the amount of flexure of the clamp spring can be reduced while securing the necessary clamping force, and thus the spring life can be extended, and in the invention of claim 2, the spring force during clamping or the spring force during unclamping is the amount of flexure. Alternatively, since the clamping is performed so as to be larger than the deflection amount, there is an effect that the operating force at the time of unclamping can be reduced.

[Brief description of drawings]

FIG. 1 is a sectional front view of a 90-degree angular attachment according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a main part of the above embodiment.

3 is a sectional view taken along line III-III in FIG.

FIG. 4 is an enlarged perspective view of a main part of the above embodiment.

FIG. 5 is a diagram for explaining the operation of the apparatus of the above embodiment.

FIG. 6 is a diagram for explaining the operation of the apparatus of the above embodiment.

FIG. 7 is a diagram for explaining the operation of the apparatus of the above embodiment.

FIG. 8 is a diagram for explaining the operation of the apparatus of the above embodiment.

FIG. 9 is a partial cross-sectional front view of a spindle ram to which the device of the above embodiment is attached.

FIG. 10 is a deflection-spring force characteristic diagram for explaining the effect of the apparatus of the above-mentioned embodiment.

FIG. 11 is a sectional front view of a conventional tool attaching / detaching device.

FIG. 12 is a deflection for explaining the problems of the conventional device-
It is a spring force characteristic diagram.

[Explanation of symbols]

 32 spindle 32c taper hole (tool mounting hole) 37 draw bar 43 clamp spring 70 operation mechanism

Claims (2)

[Claims] 1. A drawbar which is movably inserted into a shaft hole of a spindle in a direction of a spindle axis and clamps / unclamps a tool in a tool mounting hole of the spindle by the axial movement, and urges the drawbar in a clamping direction. A tool attaching / detaching device provided with a clamp spring and a clamp / unclamp operation mechanism that performs a clamping operation in the process of increasing the deflection amount of the clamp spring and an unclamping operation in the process of decreasing the deflection amount. . 2. A drawbar, which is movably inserted in a shaft axis direction of a spindle in a direction of a spindle axis, and clamps / unclamps a tool in a tool mounting hole of the spindle by the axial movement, and urges the drawbar in a clamping direction. A clamp spring and a clamp operating mechanism that performs a clamp operation by compressing the clamp spring so that the spring force or the flexure amount during clamping is larger than the spring force or the flexure amount during unclamping are provided. Tool attachment / detachment device.