JPS60207736A - Tool fixture for machine tool - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tool mounting device for a machine tool in which a truncated conical receiving hole for receiving a tapered shank of a tool holder is formed and an annular end surface surrounding the periphery of the receiving hole.

The most frequently used coupling structure between the spindle head (DIN 2079) and the tapered shank of the tool holder (DIN 2080) allows the full machining forces of today's alpine machines to be transmitted to the tool without any problems. It has been determined that it is no longer suitable.

Based on DIN 2080 (taking I80 taper 50 as an example, the maximum diameter of the taper groove is approximately 701111, while the outer diameter of the spindle receiving the taper shank is 128n. , all of the lateral forces acting on the tool must be transmitted to the spindle by means of a tee shank that is thin compared to the tool spindle of the machine tool. Since the shank cannot loosen, a very high level of holding force must be generated by means of a retaining means in the spindle that pulls the tapered shank into the receiving hole.For machine tools with automatic tool change, i.e. machining centres. When carrying out a tool change operation, it must be possible to loosen the taper 9 shank by means of the holding means, for which reason a diaphragm spring actuated clamping pawl is often used.The diaphragm spring is released from the load. These pawls then approach behind the head of the headed bolt at the end of the tapered shank and, with residual force, pull the chi/bump shank into the receiving hole. Even at very high bias levels, the retraction force is considerably reduced, and the large radial cutting forces acting on the tool, which protrudes significantly from the spindle, cause the Qi-9 shank to temporarily remain in the receiving hole in the spindle. However, there is a drawback that chattering occurs at this time.
The maximum diameter of the shank is slightly smaller than the outside diameter of the spindle. The bending strength of a tool holder is determined by its minimum diameter when it is unsqueezed; however, the bending strength of a tool holder depends only on its maximum diameter.

Also known drilling tools (German patent no. 3,108,439
According to No. 1, the head portion of the tool has a cylindrical spigot portion that engages in a cylindrical fitting hole in the tool holder. In the area of the cylindrical fitting hole, the tool holder has two radially oppositely extending internal threads, into each of which a tightening screw formed with a conical recess is screwed. A radially movable clamping pin is provided in the lateral hole of the spigot part.

A conical projection is formed at each end of the clamping pin, which projections cooperate with a conical recess of the clamping screw. The axis of the female threaded portion and the axis of the horizontal hole have the following arrangement relationship. That is, when one tightening screw is loosened, this tightening screw acts on the tightening pin and presses the annular surface surrounding the spigot portion against the end surface of the tool holder. According to this bond structure,
A joint structure is obtained between the parts of the drilling tool that improves installation and replacement accuracy, can transmit high levels of torque, and has extremely high bending strength. However, in known drilling tools, the tool holder itself has a taper shankler.
The above-mentioned problems arise when connecting the tool holder to the tool spindle of the machine tool, since the tool holder is inserted into the tool spindle of the machine tool by the Young.

This invention solves the problems of conventional devices as described above, and increases the bending resistance of the connection between the tool spindle and tool holder of a machine tool, enabling high levels of torque transmission and To provide a mounting device that allows the insertion of a spindle head of a tool holder equipped with a conventional teno shank in accordance with the above requirements.

According to the invention, in the area of the truncated conical receiving hole, the spindle head has a cylindrical fitting hole which receives the cylindrical spigot part of the second tool holder, which has a cylindrical spigot part instead of the tapered shank of the first tool. The diameter of this fitting hole is slightly smaller than the maximum diameter of the truncated conical receiving hole, and the axial length from the end of the fitting hole measured from the end face to the end of the truncated conical receiving hole. In the region of the cylindrical fitting hole, the spindle head has two internal threads extending in opposite directions in the radial direction, and the six internal threads are formed with a conical protrusion or a conical recess. The tightening screws are screwed together, and a tightening pin is provided in the horizontal hole of the spigot part so as to be movable in the radial direction, and a conical recess or conical protrusion is formed at each end of the tightening pin. The recess and projection cooperate with the conical projection or conical recess of the tightening screw, respectively, and the distance from the end surface of the shaft of the internal thread is slightly larger than the distance of the axis of the horizontal hole from the annular surface of the tool holder. When one of the tightening screws is tightened, the tightening screw acts on the tightening pin and presses the annular surface and the end surface toward each other.

For this purpose, the present invention provides a truncated conical receiving hole and a cylindrical fitting hole in the spindle head of the machine tool, thereby connecting the first tool holder or cylindrical spigot portion with a conventional tapered shank. A second tool holder having a radially movable clamping pin therein is selectively inserted into the spindle.

The tool user can continue to use a conventional first tool holder with a tapered shank to perform operations where the rotational or bending moments are not too large. Additionally, the user may also optionally use a second tool holder which is received directly into the cylindrical fitting hole of the system spindle head by means of a cylindrical spigot portion. Use of this tool holder provides a connection between the spindle head and the tool holder that is strong against bending and capable of transmitting high torque. That is,
Due to the axial misalignment between the axis of the clamping screw and the axis of the clamping flange pin, the effective axial force component causes the clamping screw to also be moved axially, causing the annular surface of the tool holder to move with a large piascus. Press it against the end face of the spindle head. Since the annular surface and the end surface fit strongly together, most of the torque is transmitted through the frictional engagement on these surfaces. The remaining 90% of the torque is transmitted through the tightening screw, tightening pin, and K.

It is also important that when the annular surfaces securely engage the end faces, the lateral forces acting on the tool are transmitted by these surfaces to the relatively large diameter section of the spindle. This makes the connection between the tool spindle and the tool holder very strong against bending. That is, the vibration of the tool during machining is reduced, the A-work of the machine tool is well transmitted to the tool, and the length of the cantilever beam relative to the tool can be increased. This increases cutting efficiency and reduces machining time. Another advantage is that all elements involved in the tightening operation and which can become fatigued due to frequent tool changes, namely the clamping screws or clamps e7, can be easily replaced.

The present invention will be explained in detail below using examples.

A tool spindle 1 of a machine tool is rotatably mounted in a headstock 2. The head 1a of the spindle 1 is formed with truncated conical receiving holes 3m and 3b. Receiving hole 3m, 3b
shall be of a shape corresponding to DIN 2079 or the corresponding ISO standard. The periphery of the receiving hole 3a is surrounded by a flat annular end surface 4 extending at right angles to the axis A of the spindle.

In the region of the receiving holes 3m and 3b, the spindle head 1a
has a cylindrical fitting hole 5 concentric therewith. The diameter of the fitting hole 5 is slightly smaller than the maximum diameter D1 of the receiving hole 3m, 3b. The length L measured from the end surface 4 to the end of the fitting hole 5 is:
It is p shorter than the axial length Ll to the end of the receiving hole 3b.

When selecting the diameter of the fitting hole 5, the end face 4 and the fitting hole 5 should be
A portion 3a that has a sufficient length in the axial direction and is suitable for reliably supporting the tapered shank 6 of the first tool holder 20 shown in FIG. No. It has been found that the diameter of the fitting hole 5 is preferably about 4 to 10% smaller than the maximum diameter D1 of the receiving hole 31, preferably about 6.5%. Qi/by l5O-50
In this case, the maximum diameter of the receiving hole 3a D I Fi69.
It is 85 mytt. If the diameter of the fitting hole 5 is selected in order of 65.5, the axial length of the receiving hole 3 will be approximately 14-
It is 9111. This length is sufficient to properly support the front end of the tapered shank 6.

The fitting hole 5, in which the rear port of the tapered shank 6 is also supported by the receiving hole 3b, does not extend over the entire length L1 of the receiving hole. End face 4
The axial length L to the end of the fitting hole 5 needs to be about 172 to 2/3 of the axial length Ll to the end of the receiving hole 3b, as measured from . From this point K, a receiving hole 3b is formed which fully supports the rear end of the tapered shank 6.

Furthermore, in the area of the fitting hole 5, the spindle head 1a
K is formed with two internal threads 7.8 extending in opposite directions in the radial direction, and a tightening screw 9.K is formed in the truncated threads 7, 8. IO is screwed in from the radial direction. The m-head screw 9 has a conical protrusion 9a, and the tightening screw lO has a truncated conical recess 10&. The axes A1 of the female threaded portions 7, 8 are spaced apart from the end surface 4 by al.

The cylindrical spigot portion 12 of the tool holder 11 is fitted into the fitting hole 5 with an extremely small gap (actually, there is almost no gap). At the free end 111 of this tool holder 11 a tool, such as a drilling head, an internal cutting tool, a milling tool, a reamer or a broach, or the like, is mounted. These tools are either fixedly attached to the tool holder 11 or are replaceably attached. Alternatively, they may be connected via an intermediate member.

A cylindrical tightening hole is inserted into the horizontal hole 13 formed in the spigot portion 12.
14t - Mounted so that it can be freely displaced in the radial direction. Tightening pin 1
4 is formed with a conical projection 14m at one end thereof, which engages with the coveted conical recess 10m. A truncated conical recess 14b is formed at the other end, into which the conical protrusion 9a engages.

The distance a2 between the axis A2 of the horizontal hole 13 is slightly smaller than the aforementioned distance a1.

The tool holder 11 may be surrounded by a coolant supply ring. If the tool holder 11 is a rotating holder, the coolant supply ring is arranged stationary. Via this coolant supply ring, the cooling fluid supplied to the axial hole 15a of the tool holder is guided to the cutting edge of the tool.

To change the tool, press the conical projection 9a on the front end of the tightening screw.
It is only necessary to loosen the four-head screw 9 until it separates from the fitting hole 5. Along with this, the clamping pin 14 can be moved within the horizontal hole 13 until the conical end 14 of the clamping pin 140 is separated from the conical recess 10m, so the tool holder 11 is moved to the left and removed from the spindle head 1a. It can be removed.

Next, when the tool holder 11 of another tool is fitted, the spigot portion 12 is engaged with the fitting hole 5. Since the diameter D1 of the receiving hole 3a is larger outwardly than the diameter of the fitting hole 5, the receiving hole 3a facilitates the insertion operation of the spigot portion 12.

When the tightening screw 9 is screwed radially inward into the threaded portion 7, the conical protrusion 9a moves the tightening pin 14 in the radial direction.
re-engages with the recess 10m of the tightening screw lO. The effective clamping force in the radial direction of the clamping screw 90 produces a reaction force in the opposite direction of equal magnitude on the clamping screw IOK. Axis AI, A2
are offset by K from each other in the axial direction, so the two tightening screws 9.
Each of the 10 generates an axial force component of equal magnitude. Therefore, the cone angle of the protrusion of the screw 9 is 90°.
In this case, the overall tightening force is doubled by the tightening force of this tightening screw, and the annular surface 16 of the tool holder 11 is pressed against the end surface 4.
The pressing force at this time is 2 of the radial tightening force.
It's double. As is clear from FIG. 1, the outer diameter of the annular surface 16 is equal to the outer diameter of the end face 4 and approximately corresponds to the diameter of the spindle head 1a. The tool holder 11 is therefore supported over a very wide area by the spindle head 1a via these surfaces 16.4. In this way, a bending-resistant and virtually rattling-free bond is obtained between the two parts. Such a configuration example constitutes an important feature of the present invention.

Tightening screw 9 with conical protrusion 9&, conical recess 10a
a tightening screw 10, and a conical protrusion 14 at one end;
a, a conical recess 14b is provided at the other end, and the screw 9,
The use of a clamping pin 14 corresponding to 10 has proven to be particularly advantageous in practice. However, as a modification of this configuration, conical recesses may be formed in both tightening screws, and corresponding protrusions may be formed at both ends of the tightening pin. Conversely, conical protrusions may be formed on both tightening screws, and conical recesses may be formed at both ends of the tightening pin.

Next, another embodiment shown in FIG. 2 will be described.

The spindle head IS having the receiving holes 3m, 3b and the fitting hole 5t is exactly the same as that of the embodiment shown in FIG.

The end of the tool holder 11' facing the spindle head la also has the same structure as that of the tool holder 11, and therefore will be given the same reference numerals as in FIG. 1 and a description thereof will be omitted. However, in this embodiment, a fitting hole 17 is provided at the front end of the tool holder 11', and two female threads '9' radially opposite to each other are provided within the fitting hole 17.
18 and 19 are formed. A clamping screw corresponding to clamping screw 9.10 is then screwed into internal thread 18.19. When selecting the diameter D2 of the fitting hole 17, the milling tool shown in German Patent No. 3.108,439,
The spigot portion (not shown) of an inner round cutting tool or drilling head is engaged with the fitting hole 17, and fc means that the spigot portion of an intermediate member that may be inserted between the tool and the tool holder is The requirements such as engagement with the fitting hole 17 are to be satisfied.

The tool holder 11' is disclosed in the aforementioned German Patent No. 3,108,
Since the tool according to No. 3 and the tool spindle according to the invention function as an adapter, the dimensions of the connection are determined accordingly. Since the tool holder 11' is equipped with the coolant supply ring 1B'i, one identical tool holder 11' and one identical coolant supply ring can be used.
Therefore, there is an advantage that various tools having an internal coolant supply type to the cutting blade can be combined.

Finally, according to the invention, the known tool holder 2ots 3 with a tapered shank according to DIN 20BG
As shown in the figure, it can be fixed to the machine tool tool spindle of the present invention.

That is, by moving the tightening screws 9, 10'li, the two conventionally used entrainment members 21t-1 are fitted into the corresponding grooves 22 provided in the end face portion 4 of the two radially opposite entrainment members 21t-1 in a known manner. do. Then, the entrainment member 21 is inserted into the groove 23 provided in the entrainment flange 20m of the tool holder 20. Next, the tension rod 25 screwed into the taper shank or the lay load tightening is applied to the taper shank 6 by means of a collet (not shown).
When the taper shank 6 is drawn into the receiving hole 311, 3b, the taper shank 6
is supported by receiving holes 3m and 3b. Coolant is then supplied from a coolant supply ring 26 arranged concentrically around the tool holder.

In place of the fitting hole 17, the tool holder 11 may be provided with another forwardly projecting spigot portion having a lateral hole and a tightening pin therein. A tool holder of such construction is suitable for receiving a tool movement that is opposite to the principle described in German Patent No. 3,108,438. This is because such a tool has a fitting hole instead of a spigot and is equipped with two radially opposite internal threads.

As already mentioned, tools of this type can be used in combination with a tool changer.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view of a first embodiment of the invention, FIG. 2 is a partial sectional view of a second embodiment of the invention, and FIG. 3 is a conventional tool spindle of both embodiments. It is a partial sectional view showing the state where the taper shank of the tool was attached. 1... Tool spindle la-... Spindle head 2... Headstock 3m, 3b... Fractional conical receiving hole 4...
...Annular end surface 5...Cylindrical fitting hole 6...Taper shank τ8...Female threaded part 9.10...Tightening screw
9sL... Conical projection 10 &... Conical recess 11
, 11'...Second tool holder 12...Cylindrical spigot portion 53...Horizontal hole 14...Tightening pin 14a...
- Conical recess 14b... Conical protrusion 56... Annular surface 20... First tool holder

Claims (1)

[Claims] 1. Tapered shank (6) of first tool holder (20)
A receiving hole of a tool spindle (1) having a spindle head (1&) formed with a truncated conical receiving hole (am, 3b) for receiving the same, and an annular end surface (4) surrounding the periphery of the receiving hole (3a). In the region of (3g, 3b), Suby)'
A second tool holder (11,
The diameter (D) of the fitting hole (5) is slightly larger than the maximum diameter (DI) of the receiving hole (3a). Small, end face (4)
The axial length measured from the end of the fitting hole (5) is shorter than the axial length Ll) of the end of the receiving hole (3b),
In the area of the fitting hole (5), the spindle head (1a
) has two internal threads (7, 5) extending in opposite directions in the radial direction.
) T-, and each female threaded part (7, 8) has a conical projection (9
a) or the tightening screws (9, 10) formed with a conical recess (10 m) are screwed together, and the horizontal hole (
13) is provided with a clamping pin (14) movable in the radial direction, with a conical recess (14m) at each end of the clamping pin.
Alternatively, a conical projection (14b) is formed, and the recess (14b) is formed.
m) and the protrusion (14b) are respectively tightened by screws (9, 1).
0) conical protrusion (9a) or conical recess (10m)
The distance (al) from the end surface (4) of the axis (Al) of the female threaded portion (7, 8) is determined by the axis M (
A2) is slightly larger than the distance (a2) from the annular surface (1) of the tool holder (11, 11'), and the tightening screw (9, 1
0), this tightening screw will connect to the tightening pin (1).
4) to press the annular surface (16), the end surface (4), and the metal toward each other? ! -Featured tool mounting device for machine tools. 2. In claim 1, the diameter (D) of the fitting hole (5) is about 4-10%, preferably about 6.5%, of the maximum diameter (DI) of the receiving hole (3m, 3b). A tool mounting device characterized by its small size. 3. In claim 1 or 2, the axial length L from the end surface (4) to the end of the fitting hole (5) is equal to the length L from the end of the receiving hole (3b) to the end of the receiving hole (3b). A tool mounting device characterized in that the length in the axial direction is about 172 to 2/3 of Ll). 4. In claim 1, one of the tightening screws (
One has a conical recess (10a), and the other has a tightening screw (
9) has a conical projection (9a), and correspondingly, a conical projection (14m) is formed at one end of the tightening pin (14) and a conical recess (14b) is formed at the other end. A tool mounting device featuring: