JPS62282808A - Spindle heat of machine tool - Google Patents

Abstract

PURPOSE:To accelerate the tool exchanging work by separating the compressing process of a clamp spring and the shifting process of a draw bar so that the force applied to the draw bar can be made small. CONSTITUTION:When a tool 30 is to be unclamped by a spindle head 10, a slide member 16 is shifted by an unclamping cylinder 21 in the unclamping direction against the energizing force of a clamping spring 17. At this time, a draw bar 14 is energized to the clamp position by a holding spring 18, thus a collet 15 is coupled with the tool 30. Therefore, the tool 30 is held in a spindle 12 under this condition. Next, the draw bar 14 is shifted by the second cylinder piston rod 21c in the unclamping direction against the energizing force of the spring 18, and the coupling between the collet 15 and tool 30 is released. Accordingly, the force for shifting the draw bar 14 can be made small, and the tool exchange can be accelerated.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a spindle head of a machine tool such as a vertical milling machine, and is particularly suitable for speeding up the work of attaching and detaching tools. Regarding the spindle head of

[Conventional technology]

Modern machine tools, such as vertical milling machines, use tools.

By providing a changing device, various types of processing can be performed continuously. In this case, to improve machining efficiency,
There is a need to shorten the tool exchange time, and conventionally, in this tool exchange work, the end of each process is detected, and after receiving this detection signal, the next process is started. Therefore, there is a limit to how much time it takes to change tools, and this has become a technical issue that must be solved if machining efficiency is to be improved.

In order to solve the above-mentioned problems, the inventors of the present application have developed a tool changing device that performs the tool changing process using a mechanical structure such as a cam mechanism. In this device, for example, as a mechanism for unclamping a tool from a spindle, when a tool changing arm is rotated to a tool gripping position by a plate cam,
Continuously, hydraulic pressure is generated by a cylinder also driven by a plate cam, and this hydraulic pressure is supplied to the drawbar driving cylinder, thereby unclamping the tool. As a result, this plate cam type unclamping mechanism requires tool change time of 2.5 to 7 seconds, whereas the conventional method of starting the next process after detecting the end of the previous process required a tool change time of 6 to 7 seconds. The time can be shortened to 3 seconds, which speeds up the tool change process accordingly.

[Problem that the invention seeks to solve]

By the way, the greater the clamping force of the tool, that is, the larger the tool, the greater the unclamping force.To achieve this, the plate cam type unclamping mechanism developed by the inventors of the present invention requires a large unclamping force. As the diameter of the temporary cam increases, it is necessary to increase the diameter of the temporary cam, and there is a problem in that the surface pressure of the temporary cam also increases. Therefore, this plate cam type unclamping machine barrel had the problem that it was difficult to use it in large machines that required a large unclamping force.

SUMMARY OF THE INVENTION Therefore, the object of the present invention is to solve the above-mentioned problems, and to provide a machine tool that can employ the above-mentioned plate cam type unclamping barrel 1a without increasing the cam diameter even when a large unclamping force is required. The point is that it provides a spindle head for

[Means for solving problems]

The present invention includes a main spindle head of a machine tool, in which a cylindrical slide member is slidably fitted to the end of a drawbar, a locking portion that abuts the drawbar in a clamping direction is formed on the slide member, and A clamp spring consisting of a large number of disc springs is disposed between the slide member and the spindle, and a retaining spring is disposed between the slide member and the drawbar,
The first step is to move the slide member and the drawbar in the unclamping direction. It is characterized by the provision of a drawbar drive device consisting of a second cylinder.

[Effect]

In the spindle head of the machine tool according to the present invention, when unclamping the tool, first the slide member is moved in the unclamping direction by the first cylinder against the biasing force of the clamp spring. At this time, the drawbar is biased to the clamping position by the holding spring, so the collet is engaged with the tool, so that the tool is still held within the spindle in this state. Then, the drawbar is activated in the second cylinder.
When the collet is moved in the unclamping direction against the biasing force of the retaining spring, the collet and the tool become uncoupled.
The tool is removed. In this case, in addition to the urging force of the retaining spring, the force required to move the drawbar is sufficient to move the collet and disengage the tool from the spindle.

In this way, in the present invention, since the compression process of the clamp spring and the movement process of the drawbar are separated, the force applied to the drawbar can be extremely small, so there is no need to increase the size of the plate cam (the above-mentioned plate cam type amplifier). A clamping mechanism can be used to speed up tool changing operations.In this case, even if the clamp spring is compressed, the drawbar remains in the clamped position, and the tool will not come off at this point, making it easy to unclamp. The clamping spring can be compressed in advance, so that there is no time loss due to the separation of the unclamping process into two stages.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

1 to 3 are diagrams for explaining the spindle head of a vertical milling cutter according to an embodiment of the present invention, and this is an example of a so-called bed type vertical milling machine in which the spindle head moves up and down. In FIG. 3, reference numeral 1 denotes a base fixed on a foundation surface, a saddle 2 is disposed on the base 1 so as to be movable in the Y direction shown in the figure, and a table 3 is placed on the saddle 2 in the X direction shown in the figure. Furthermore, a column 4 is provided upright on the base 1. 5 is a tool changing device; 7 is a tool changing arm; the arm 7 grips a tool with gripping claws formed at both ends thereof, and descends in this state;
It is configured to rise after rotating 0°. Note 6
is the control panel.

A spindle head 10 is disposed on the column 4 so as to be movable in the Z direction in the figure, and as shown in FIG. It is rotatably inserted and supported. The spindle 12 has a cylindrical shape, and a tapered tool holding part 12a is formed on the inner surface of its lower end, and a cylindrical stopper 12b is fitted and fixed slightly above the tapered tool holding part 12a.

A drawbar 14 is inserted into the spindle 12 so as to be vertically movable. This 1'' row bar 14 is rod-shaped, and has an annular engagement groove 14a in concave contact with its lower end, and an engagement convex portion 15a of a collet 15 is engaged with the cough groove 14a. A gripping claw 15b formed at the tip of the collet 15 can be engaged with and detached from a retaining portion 30a formed at the upper end of the tool 30.

Further, a flange portion 14b is provided at the upper end of the drawbar 14.
A cylindrical slide tube 16 is inserted between the upper ends of the draw bar 14 and the spindle 12 so as to be slidable a predetermined distance. A locking portion 16a that comes into contact with the drawbar 14 when moved upward, that is, in the clamping direction, is formed on the inner surface of the slide tube 16, and an upper end portion 16b of the locking portion 16a projects upwardly from the drawbar 14. A clamp spring 17 consisting of a large number of disc springs is disposed between the lower end surface of the slide cylinder 16 and the stopper 12b, and a clamp spring 17 is provided between the upper part of the slide cylinder 16 and the flange portion 14b of the drawbar 14. A retaining spring 18 made of a coil spring is provided.

Further, a drawbar drive device 20 is provided at the upper end of the body 11.
is installed. This drawbar drive device 20 includes a parent-child type unclamp cylinder 21, an air booster type first hydraulic pressure supply vt'l 122, and a temporary cam type second hydraulic pressure supply device 2.
It is composed of 3.

A cylinder body 21a of a first cylinder for pressing the slide tube 16 of the unclamp cylinder 21 is fixed to the body 11, and the cylinder body 21a is fixed to the body 11.
A piston rod 21C of a second cylinder for pressing the drawbar 14 is inserted into the piston rod 21b inserted therein, and the piston rod 21b of the first cylinder also serves as the cylinder body of the second cylinder. are doing. In addition, 21d and 21e are each piston rod 2.
This is a return spring for moving 1b, 21c to a clamped state.

The first hydraulic pressure supply device 22 is a device that generates hydraulic pressure with a piston rod 24d by applying air pressure to a piston 24c, and the air chamber 24a of the air booster 24 is connected to an air supply source via an air supply passage 25a. 25
A switching valve 25b is interposed in the passage 25a. Also, the oil chamber 24 of the air booster 24
b is connected to the oil charge tank 26 via an oil supply passage 26a, and a reversal valve 26 is connected to the passage 26a.
b. A switching valve 26e is installed. This oil charge tank 26 is for supplying hydraulic oil to the oil chamber 24b, and the switching valve 26C allows the tool to be manually unclamped when the plate cam type second oil supply device 23 is not operated. It is intended to do so. Also, the upper end of the oil charge tank 26 is connected to the air passage 25C.
is connected to the air supply source 25 via the passage 25.
e is provided with a pressure reducing valve 25d and a switching valve 25e.

Further, a first hydraulic pressure supply passage 26d branches from between the switching valve 26C and the air booster 24, and a second hydraulic pressure supply passage 26e branches from between the switching valve 26c and the check valve 26b of the oil supply passage 26a. These are connected to the first hydraulic chamber 21r of the first cylinder and the second hydraulic chamber 21g of the second cylinder, respectively. Note that the second hydraulic pressure supply passage 26g is made of a flexible hose.

Further, the plate cam type second hydraulic pressure supply device 23 includes a disk-shaped plate cam 2 that is rotationally driven by a drive motor (not shown).
7 and a hydraulic pressure generating cylinder 28 driven by the cylinder 28, the hydraulic chamber 28a of the cylinder 28 is connected to the second hydraulic chamber 21g of the unclamping cylinder 21 by a hydraulic pressure supply hose 28b.

Next, the effects of this embodiment will be explained.

In the device of this embodiment, when the tool 30 is clamped, the slide tube 16 is moved to its upper end position 1 by the clamp spring 17, as shown by the solid line in FIG. 1, and the drawbar 14 is thereby moved upward. The collet 15 is pulled up to the clamp position where the gripping claws 15b of the collet 15 engage with the engaging portion 30a of the tool 30, and as a result, the tool 30 is held in the tool holding portion 12a of the spindle 12 in a clamped state. There is.

In the above state, the operation for exchanging the tool 30 is performed in the following steps.

■ To replace the tool 30, the spindle head 10 first rises along the column 4 to its rising end, which is the tool changing position. The conduction position is switched to the opposite position. Then, compressed air of, for example, 5 kg/d is supplied from the air supply source 25 to the air chamber 24a of the air booster 24. Then, as a result, the oil pressure in the oil chamber 24b increases to, for example, 60.
kg/ad, and this hydraulic fluid is supplied to the first hydraulic chamber 21f of the unclamp cylinder 21 through the first hydraulic pressure supply passage 26d.

(2) Then, the piston rod 21b of the first cylinder descends due to the hydraulic fluid, presses the upper end of the slide tube 16, and compresses the clamp spring 17.

At this time, the drawbar 14 is held at the clamp position, which is the rising end position, by the holding spring 18, so the tool 30
is held in a clamp position by the drawbar 14 via a collet 15 at the lower end.

When the spindle head 10 rises to the tool changing position at the upper end, the tool changing arm 7 rotates and its gripping claws grip each tool, and then the temporary cam 27 rotates to move the piston of the hydraulic pressure generating cylinder 28. 28c moves forward, hydraulic pressure for the second cylinder is generated, and hydraulic oil from the hydraulic chamber 28a of the cylinder 28 is supplied to the second hydraulic chamber 21g of the second cylinder.

■ By supplying the above hydraulic oil, the second piston rod 21
c is lowered to lower the drawbar 14 against the biasing force of the holding spring 18. Then, this causes the drawbar 14
The collet 15 engaged with the lower end of the collet 15 is also lowered and expands outward as shown by the two-dot chain line in FIG.
5b and the engagement portion 30a of the tool 30 are disengaged. At the same time, by pressing the upper end of the tool 30 with the lower end of the draw bar 14, the tool 30 and the spindle 12 are
The fitting will be removed.

- Next, the tool changing arm 7 descends while gripping the tool, rotates 180 degrees, and then rises, so that the tool attached to the spindle 12 is stored in the pot of the tool changing device 5. At the same time, the tool to be installed is inserted into the spindle 12.

When clamping this tool, place the tool on the spindle 12.
The above-mentioned No. 1. When the second cylinder is returned to its original position, the drawbar 14 is returned to its original position by the holding spring 18, and is also urged in the clamping direction via the slide tube 16 by the urging force of the clamp spring 17, thereby achieving a predetermined clamping force. The tool 30 is thereby clamped within the spindle 12.

In this way, in this embodiment, the process of compressing the clamp spring 17 and the process of moving the drawbar 14 in the unclamping direction are separated, so that the force acting on the movement of the drawbar 14 in the unclamping direction is , the urging force of the holding spring 18 and the collet 15 are moved, and the tool 30
Only the sum of the force required to unfit the holding portion 12a of the spindle 12 from the holding portion 12a of the spindle 12 is required, which is very small. Therefore, the temporary cam type hydraulic pressure generating mechanism described above can be employed as the hydraulic pressure generating mechanism for the hydraulic oil to the second cylinder for moving the drawbar 14 without increasing the size of the temporary cam.

Furthermore, in the device of this embodiment, even when the clamp spring 17 is compressed by the first cylinder, the drawbar 14
is held in the clamp position by the holding spring 18, so
While the clamp spring 17 is compressed, the tool 30 does not come off the spindle 12 yet. Therefore, since the clamp spring 17 can be compressed in advance before the tool 30 is gripped by the tool changing arm 7, the work time becomes longer due to the above-mentioned unclamping operation being separated into two steps. In the end, in this embodiment, by adopting the above-mentioned plate cam type unclamping mechanism, the tool change time was shortened from the conventional 6 to 7 seconds to 2.5 to 3 seconds.

Note that in the above embodiment, the first. Hydraulic pressure to the second cylinder is supplied to the air booster 24. Although an example in which the hydraulic pressure is generated by the temporary cam type cylinder 28 has been described, the present invention does not necessarily require the adoption of such a mechanism for generating hydraulic pressure, and the point is that the hydraulic pressure is generated by the compression process of the clamp spring and the movement process of the drawbar. It may be configured to separate the

Further, in the above embodiment, the case where the unclamping cylinder 21 is a parent-child type cylinder has been described, but it may of course be other types of cylinders.

Furthermore, although the above embodiment describes a case where the present invention is applicable to a vertical milling machine, the present invention is not limited to this, and is effective if applied to a machine tool equipped with a tool changing device such as a horizontal milling machine or a lathe.

〔Effect of the invention〕

As described above, according to the spindle head of a machine tool according to the present invention, the slide member for compressing the clamp spring is slidably fitted to the drawbar, and the holding spring for holding the drawbar in the clamp position is provided. , a slide member, and a first one for moving the drawbar. Since a drawbar drive device consisting of a second cylinder is provided, the force required to move the drawbar is extremely small, and even when a large ramp force is required, a plate cam type unclamping mechanism can be used, making it possible to change tools. This has the effect of speeding up the work.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional side view of the spindle head of a vertical milling machine according to an embodiment of the present invention, Fig. 2 is a schematic configuration diagram including the hydraulic pressure generation mechanism, and Fig. 3 is a perspective view of a vertical milling machine to which the above embodiment is applied. It is a diagram. In the figure, 10 is the spindle head, 12 is the spindle, 14 is the drawbar, 15 is the collet, 16 is the slide member, 16a is the locking part, 17 is the clamp spring, 1
8 is a holding spring, 20 is a drawbar drive device, 21 is an unclamp cylinder, and 30 is a tool. Patent applicant Morisei A Seisakusho Co., Ltd. Agent
Patent Attorney Tsutomu Shimofu Figure 3

Claims (2)

[Claims] (1) By inserting a drawbar into the spindle and moving the drawbar forward and backward, the collet engaged with the tip of the drawbar is engaged with and disengaged from the inner end of the tool inserted into the spindle, thereby causing the tool to move forward and backward. A cylindrical slide member is slidably fitted to the end of the drawbar in the spindle head of a machine tool which can be attached to and detached from the spindle. A clamp spring is disposed between the slide member and the spindle to form a stop portion, and includes a plurality of disc springs that bias the slide member in the clamping direction, and a clamp spring is disposed between the slide member and the drawbar. A workpiece characterized in that a holding spring is disposed to bias the drawbar in the clamping direction, and a drawbar drive device is provided that includes a first cylinder and a second cylinder that move the slide member and the drawbar in the unclamping direction, respectively. The main shaft head of the machine. (2) The spindle head of a machine tool according to claim 1, wherein the drawbar drive device is a parent-child cylinder in which the piston rod of the first cylinder also serves as the cylinder body of the second cylinder.