JPH06210504A - Tool attachment/detachment device - Google Patents

Abstract

PURPOSE:To provide a tool attachment/detachment device which can conduct the exchange of tools by means of uniform clamp force surely in a short time without any wrong action. CONSTITUTION:The tool attachment/detachment device of a machine tool is constituted by being equipped with a nut 9 screwed on the end part of a main spindle 4; a tool retaining member 10 to be furnished the end part of the main spindle 4 by means of the nut 9; and a lock mechanism 12 to lock the nut 9 in a rotary direction. In this instance, the lock mechanism 12 is equipped with a lock recessed part 9c formed on the outer periphery surface of the nut 9 and a lock pin 12c to be brought in press-contact with the outer periphery surface of the nut 9, and when the main spindle 4 is rotated, the lock recessed portion 9c and the lock pin 12c are engaged with each other.

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 used for an automatic tool changing device of a machine tool such as a machining center, and more specifically, it is of a so-called nut runner type in which a tool holding member is fixed to a spindle with a tightening nut. A tool attaching / detaching device.

[0002]

2. Description of the Related Art Conventionally, as a nut runner type tool attaching / detaching device, there is a device disclosed in Japanese Examined Patent Publication No. 3-4324. This is a nut that has a tool holding member having a male taper part that fits into a female taper hole of the main shaft, a lock hole and a positioning sensor detection protrusion on the outer circumference, and tightens and fixes the tool holding member to the lower end part of the main shaft. And a lock mechanism having a hydraulically operated lock pin that engages with the lock hole, and a sensor for positioning the lock hole and the lock pin.

In the above conventional apparatus, when a tool change signal is issued, the main shaft rotates at a low speed until the lock hole of the nut comes to a position facing the lock pin, and when both of them face each other, the positioning sensor outputs a main shaft stop signal. Then, the spindle stops at that position. Next, the lock mechanism hydraulically advances the lock pin, whereby the lock pin engages with the lock hole and locks the nut. In this state, the spindle is rotated in a predetermined direction to loosen the nut, and the tool is replaced. When mounting the tool, the spindle is rotated in the opposite direction to the above by a predetermined angle while the nut is locked.
The above publication describes that the sensor can be dispensed with by using the orientation function on the machine tool side for positioning. However, when only the orientation function is used, the tightening force becomes unstable due to the variation in the thickness of the flange part of the tool holding member,
Disabling the sensor is difficult.

[0004]

As described above, the above-mentioned conventional apparatus requires a sensor for positioning. However, because of the structure, the installation location of this sensor must be close to the cutting point, so that chips, etc. May cause malfunction or malfunction.
Moreover, in a machine of the type in which the spindle is replaced together with the attachment, there is a problem that the electrical wiring required to operate the sensor becomes difficult.

Further, while the spindle is rotated at a low speed, the positioning sensor detects the position of the projection of the nut, and the lock hole and the lock pin are aligned with each other. There is a problem that it takes time.

Furthermore, since the lock mechanism has a structure in which the lock pin is moved by a mechanism such as a solenoid valve and a hydraulic cylinder, the device is complicated and expensive, and there is also a problem that maintenance and inspection are troublesome. .

Further, since the structure in which the main shaft is rotated by a predetermined angle is adopted, the thickness of the flange portion of the tool holding member clamped by the nut is not completely the same for each tool holding member, and long-term The tightening force may fluctuate due to wear of the threaded portion during use, and as a result it is difficult to obtain a sufficient clamping force.

The present invention has been made in view of the above problems of the prior art, does not require a sensor for positioning, and needs to provide a complicated mechanism such as a solenoid valve for operating a lock pin and a hydraulic cylinder. It is an object of the present invention to provide a tool attaching / detaching device capable of reliably exchanging tools with a uniform clamping force in a short time without malfunction.

[0009]

According to a first aspect of the present invention, a nut screwed on a spindle end portion of a machine tool, a tool holding member mounted on the spindle end portion by the nut, and the nut are rotated in a rotating direction. And a lock mechanism for locking the main shaft in a state where the nut is locked by the lock mechanism.
Alternatively, in the tool attaching / detaching device in which the tool holding member is tightened or loosened with respect to the main shaft by rotating in the reverse direction, the lock mechanism includes a lock concave portion provided on the outer peripheral surface of the nut, and a tool attaching / detaching tool. A lock pin, which is sometimes pressed against the outer peripheral surface of the nut with a predetermined biasing force, is provided, and the lock recess is engaged with the lock pin while the main shaft is rotated by a predetermined angle. .

According to a second aspect of the present invention, in the first aspect of the present invention, the spindle is set to a predetermined torque so that the tool holding member is pressed against the end surface of the spindle with the lock pin engaged with the lock recess. It is characterized by rotating an arbitrary angle until it becomes.

[0011]

According to the tool attaching / detaching device of the present invention, the lock pin is pressed against the outer peripheral surface of the nut by the elastic force of the spring or the like. In this state, for example, when the tool holding member is removed, when the main shaft is rotated, the lock pin and the lock recess of the nut are naturally engaged with each other, and the lock pin locks the nut in the rotation direction. When the main shaft is further rotated, the nut rotates relatively to the loose side, and the tool holding member can be removed. On the other hand, when attaching a tool, the tool holding member is inserted and fitted into the main shaft with the lock pin and the lock recess engaged with each other, and the main shaft is rotated in the opposite direction to the above. As a result, the nut presses the tool holding member against the spindle, and the tool holding member is clamped on the spindle.

According to the second aspect of the invention, when the tool is attached, the spindle is rotated by an arbitrary angle until the drive torque required for the rotation of the spindle reaches a predetermined value.

As described above, according to the present invention, as the lock mechanism, the lock pin is pressed against the outer peripheral surface of the nut with a biasing force, and the nut is rotated to naturally engage the lock pin and the lock recess. Since this is adopted, a sensor or the like for positioning the lock pin and the lock recess can be eliminated, and the risk of failure or malfunction can be avoided. Further, since a mechanism such as a hydraulic cylinder for operating the lock pin is not necessary, the lock mechanism and eventually the device can be constructed inexpensively and easily.

Further, since the lock pin is naturally locked by rotating the main shaft and the nut is loosened by further rotating the main shaft as it is, the lock pin and the lock recess are positioned by the sensor as compared with the conventional method. The time required for tool change work can be shortened.

Further, according to the second aspect of the present invention, the main shaft is rotated by an arbitrary angle until the predetermined torque is reached in the state where the lock pin is engaged with the lock recess. Therefore, the flange portion tightened by the nut of the tool holding member. Sufficient clamping force can be obtained even if there is unevenness in thickness, etc., or if the nut and the threaded portion of the spindle are worn.

[0016]

Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 to 14 are views for explaining a tool attaching / detaching device in a machine tool according to an embodiment of the present invention, FIG. 1 is a sectional side view of the tool attaching / detaching device, FIG. 2 is a side view of a spindle, and FIG. Is a bottom view of the spindle, FIG. 4 is a plan view of the tool holding member, FIG. 5 is a side view of the tool holding member, FIG. 6 is a sectional side view of the nut, FIG. 7 is a bottom view of the nut, and FIG. 8 is a sectional view of the spindle device. Side view, FIG. 9 is a partial cross-sectional plan view of the exchange arm, FIGS.
FIG. 14 is a partial cross-sectional side view for explaining the operation.

First, in FIG. 8, reference numeral 1 is a spindle device in which the tool attaching / detaching device of the present embodiment is adopted, 2 is a housing movably supported in the vertical direction by a column (not shown), and 3 is inserted into the housing 2. The fixed main barrel 4 is a main shaft rotatably supported by the housing 2 via a lower bearing 5 and an upper bearing 6.

The main shaft 4 has a cylindrical shape and has a housing 2
It is rotationally driven by a drive motor 7 arranged inside. A sensor 1 for detecting a rotation angle is provided above the spindle 4.
5, and a detection ring 16 are provided, and a tool attaching / detaching device 8 is attached to the lower end portion. The detection ring 16 is fixed to the main shaft 4, and the sensor 15 is fixed to the upper end of the housing 2.

The tool attaching / detaching device 8 is, as shown in FIG. 1, a nut 9 screwed to the lower end of the spindle 4, and a tool holding member which is attached to the spindle 4 by the nut 9 and holds the tool T. 10 and a lock mechanism 12 arranged on the exchange arm 11 side.

At the lower end of the main shaft 4, as shown in FIGS. 1 to 3, a male screw 4a screwed with the nut 9, a male taper 4b with which the tool holding member 10 is fitted, and the tool holding member. A contact end surface 4c with which 10 is pressed is formed, and a detent key 13 is bolted to the contact end surface 4c.

As shown in FIGS. 4 and 5, the tool holding member 10 is formed with a taper hole 10a which engages with the male taper 4b of the main shaft 4, and the main shaft 4 is formed in a flange portion 10f on the periphery thereof. Contact end face 10b closely contacting the contact end face 4c of
And a key groove 10c that engages with the detent key 13 of the main shaft 4 and transmits the rotational force. Further, the gripping flange 10 formed below the flange portion 10f.
A V-shaped grip 10e held by the exchange arm 11 shown in FIG. 1 is formed in d. This exchange arm 11 is, as shown in FIGS. 1 and 9, an exchange shaft 11 supported by a housing 11a so as to be rotatable and axially movable.
It is fixed to the lower end of b and is movable in the left-right direction in FIG. 1 together with the housing 11a. This allows
The tool T can be exchanged by moving the tool holding member 10 in the axial direction of the spindle by H (see FIG. 5).

As shown in FIGS. 6 and 7, a female screw 9a is formed at the upper end of the inner surface of the nut 9 and is screwed into the male screw 4a of the main shaft 4, and the lower end thereof has a flange portion of the tool holding member 10. A clamp claw 9b for pressing 10f is formed. Further, a lock recess 9c for locking the nut 9 is formed on the outer peripheral surface of the nut 9.

As shown in FIGS. 1 and 9, the lock mechanism 12 is attached to the housing 11a (apparatus fixing portion). The lock mechanism 12 has a slide hole 12a formed in a protrusion 11c protruding from the housing 11a, a slider 12b slidably disposed in the slide hole 12a, and a lock pin at the tip of the slider 12b. 1
It has a structure in which 2c is fixed. In addition, the slider 1
An urging spring 12d is provided at the rear end of 2b, whereby the lock pin 12c can be pressed against the outer peripheral surface of the nut 9 with a predetermined urging force.

Next, the operation and effect of the apparatus of this embodiment will be described mainly with reference to FIGS.

First, the tool holding member 1 mounted on the spindle 4.
The case of removing 0 will be described. When the tool change command is not issued, as shown in FIG. 10, the lock mechanism 1
2 and the exchange arm 11 are located apart from the nut 9. In addition, the clamp claw 9b of the nut 9 and the tool holding member 1
As shown in FIG. 10B, the 0 key grooves 10c are in a positional relationship that does not match each other.

In this state, if a tool change command is issued,
As shown in FIG. 11, the lock mechanism 12 and the replacement arm 11 move forward in the right direction of the drawing to press the lock pin 12c against the outer peripheral surface of the nut 9, and at the same time, the grip claw 11d of the replacement arm 11 fixes the V-shaped grip 10e. Hold it. afterwards,
When the main shaft 4 is rotated in the direction of the arrow, the lock pin 12c
The nut 9 rotates in the same direction while being pressed against the nut 9, and as shown in FIG. 12, the lock pin 12c engages with the lock concave portion 9c provided on the outer peripheral surface of the nut 9, thereby The nut 9 is fixed in the rotation direction.

Further, as shown in FIG. 12B, when the main shaft 4 is rotated in the arrow direction by a predetermined angle (α) with the nut 9 fixed, the clamp claw 9b of the nut 9 is rotated.
And the key groove 10c of the tool holding member 10 are aligned as shown in FIG. In this state, when the replacement arm 11 is moved downward, the tool holding member 10 has its key groove 10c portion descended through the inside of the clamp claw 9b,
As shown in FIG. 14, it is removed from the main shaft 4.

Next, when the exchanging arm 11 is rotated 180 degrees, the tool holding member grasped by the grasping claw 11d 'on the opposite side of the exchanging arm 11 coincides with the axis of the spindle 4. When the exchange arm is raised in this state, the key groove 10c of the tool holding member 10 rises through the inside of the clamp claw 9b, and the tapered hole 10a fits into the male taper 4b of the main shaft 4. At this time, the nut 9 is locked by the lock pin 12c. In this state, if the main shaft 4 is rotated in the opposite direction to the driving torque thereof reaching a predetermined value, the tool exchange is completed.

As described above, in this embodiment, the lock pin 12
By rotating the nut 9 with the main shaft 4 in a state in which c is pressed against the outer peripheral surface of the nut 9, the lock pin 12c is naturally engaged with the lock recess 9c on the nut 9. There is no fear of failure or malfunction like the case of positioning by using, and reliability can be improved.

Further, the lock pin 1 is used as the lock mechanism 12.
Since the structure in which the 2c is pressed against the nut 9 using the elastic force of a spring or the like is adopted, the device is simpler, the cost is suppressed, and the maintenance and inspection work is easier than the mechanism using a hydraulic cylinder or the like. Can be reduced.

Furthermore, the nut 9 is attached to the lock pin 12c.
Since the main shaft 4 is rotated by an arbitrary angle until it reaches a predetermined torque after being fixed by the above, there is an error in the thickness of the flange portion 10f of the tool holding member 10 clamped by the nut 9, and the nut 9 and Even if the threaded portion of the spindle 4 is worn, the tool holding member 10 can be tightened with a constant tightening force.

FIG. 15 shows a modification of the exchange arm in the above embodiment. In this modification, a structure is adopted in which the lock pin 12c of the lock mechanism 12 is pressed against the nut 9 by the turning operation of the replacement arm 11. In this pressure contact state,
By rotating the main shaft 4, the lock concave portion 9c and the lock pin 12c are engaged with each other, whereby the nut 9 is fixed and the tool holding member 10 is attached and detached. This modification can be applied not only to the above-described machine tool of the type in which the exchange arm moves in the direction perpendicular to the axis, but also to the machine tool of only the type in which the swing arm and the vertical movement are performed.

In the above embodiment, the case where the tool attaching / detaching device is directly provided at the lower end of the spindle arranged in the vertical direction has been described, but the tool attaching / detaching device of the present invention can be applied to machine tools other than the above. Can be adopted.

FIG. 16 shows an example adopted in a machine tool provided with a tool attachment. In the figure, 20 is a spindle device equipped with a tool attachment.
The motor case 22 is inserted and disposed in the cylindrical housing 21 so as to be movable back and forth in the axial direction.
A shaft feed motor 23 for moving the motor case 22 in the axial direction is mounted on the upper end of the shaft feed motor 2.
The ball screw 24 connected to the output shaft 23a of No. 3 is screwed into the upper end of the motor case 22.

A clamp mechanism 25 is provided at the lower end of the housing 21. The clamp mechanism 25
The tool attachment 26 is detachably attached to the lower end of the housing 21.

The tool attachment 26 is composed of an attachment case 27, a vertical main shaft 28 arranged in the attachment case 27 in the vertical direction, and a horizontal main shaft 29 arranged in the horizontal direction.

A tool holding member 30 is detachably attached to a right end portion of the horizontal main shaft 29 in the drawing with a nut 31. A lock mechanism 32 is arranged beside the nut 31. The lock mechanism 32 presses the lock pin 33 against the outer periphery of the nut 31, and by rotating the horizontal main shaft 29, the lock pin 33 engages with the lock recess 31a of the nut 31 to lock the nut 31. Fix it.

Also in this modification, the same effect as that of the above embodiment can be obtained. Further, since the sensor is not necessary and therefore the wiring for the sensor is also unnecessary, it can be applied to the case of exchanging the entire tool attachment 26 as in the present embodiment.

As described above, according to the tool attaching / detaching device of the present invention, the lock pin is brought into pressure contact with the nut, and the lock pin is engaged with the lock recess by rotating the nut. Since the positioning sensor is not required, the problem of malfunction due to chips or the like can be solved, and the structure of the lock mechanism can be simplified. Further, since it is not necessary to provide electrical wiring for the sensor, it can be adopted in a machine tool of a type in which the spindle is replaced together with the attachment, and the number of applicable models can be increased.

Further, in the invention of claim 2, after fixing the nut, the main shaft is rotated by an arbitrary angle until a predetermined torque is obtained. Therefore, there is an error in the thickness of the flange portion clamped by the nut of the tool holding member. There is an effect that a sufficient tightening force can be obtained even when the nut and the threaded portion of the main shaft are worn.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional side view of a tool attaching / detaching device for a machine tool according to an embodiment of the present invention.

FIG. 2 is a side view of the spindle in the above embodiment.

FIG. 3 is a bottom view of the spindle in the above embodiment.

FIG. 4 is a plan view of a tool holding member in the above embodiment.

FIG. 5 is a side view of the tool holding member in the above embodiment.

FIG. 6 is a sectional view of a nut in the above embodiment.

FIG. 7 is a bottom view of the nut in the above embodiment.

FIG. 8 is a cross-sectional side view of a spindle device that employs the tool attaching / detaching device of the above embodiment.

FIG. 9 is a partial cross-sectional plan view of the exchange arm in the above-described embodiment.

FIG. 10 is a diagram for explaining the operation of the above embodiment.

FIG. 11 is a diagram for explaining the operation of the above embodiment.

FIG. 12 is a diagram for explaining the operation of the above embodiment.

FIG. 13 is a diagram for explaining the operation of the above embodiment.

FIG. 14 is a diagram for explaining the operation of the above embodiment.

FIG. 15 is a partial cross-sectional plan view of a modified example of the exchange arm in the above embodiment.

FIG. 16 is a side view of a modified example of the spindle device in the above embodiment.

[Explanation of symbols]

 4 Spindle 8 Tool attachment / detachment device 9 Nuts 9c, 31a Lock recess 10,30 Tool holding member 12,32 Lock mechanism 11a Housing (apparatus fixing part) 12c, 33 Lock pin

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kiyoyuki Fukushima 106 Kita-Koriyama-cho, Yamato-Koriyama-shi, Nara Mori Seiki Co., Ltd.

Claims (2)

[Claims] 1. A lock, comprising: a nut screwed on a spindle end of a machine tool; a tool holding member mounted on the spindle end by the nut; and a lock mechanism for locking the nut in a rotational direction. In the tool attaching / detaching device configured to tighten or loosen the tool holding member with respect to the main shaft by rotating the main shaft forward or reverse in a state where the nut is locked by the mechanism, the lock mechanism is
A lock recess formed in the outer peripheral surface of the nut, and a lock pin that is pressed against the outer peripheral surface of the nut with a predetermined biasing force when the tool is attached or detached, and while rotating the main shaft by a predetermined angle,
A tool attaching / detaching device, wherein the lock recess and the lock pin are configured to engage with each other. 2. The spindle according to claim 1, wherein the spindle is rotated by an arbitrary angle until a predetermined torque is reached so that the tool holding member is pressed against the end surface of the spindle while the lock pin is engaged with the lock recess. Characteristic tool attachment / detachment device.