JPH0232323Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention provides a tool mounting attachment that is attached to a tool mounting part of an NC machine tool, such as a tool post, by a manipulator of an automatic tool changer, to the tool post. This invention relates to a tool clamping device for firmly clamping.

(Prior art and its problems) For example, a tool mounting attachment that is mounted on a tool post of a numerically controlled turret lathe by a manipulator of an automatic tool changer has a tool mounting attachment that fits tightly into a tapered hole in the tool post. A tapered protruding shaft portion is provided. The clamp of the tool attachment attachment pulls the tapered protruding shaft portion fitted into the tapered hole inward to closely fit the two, and the clamp of the tool attachment attachment can be used as needed. This is done by bringing the annular end surfaces formed around the axis on the attachment side and the tool post side into surface contact with each other.

A conventional tool clamping device of this kind has a retracting shaft that can be freely engaged with and disengaged from the tip of the protruding shaft, and a retracting shaft that is inserted into the tool as a means for inwardly retracting the tapered protruding shaft of the tool mounting attachment. It used a multi-stage disc spring that pulled in the opposite direction. Such a conventional clamp device using a disc spring is suitable for machine tools that perform heavy cutting or machining with a large overhang where the cutting force of the cutting tool attached to the tool mounting attachment exceeds the biasing force of the disc spring. When applied to a tool, there is a risk that the clamp for the tool attachment may loosen unexpectedly, which poses a safety problem. Moreover, such conventional devices have a large number of parts and a complicated structure, resulting in high manufacturing costs and poor durability.

(Means for Solving the Problems) The present invention provides a tool clamping device that can solve the above-mentioned problems, and its features are as follows:
A contact surface 16 that contacts the contact surface 15 of the tool attachment section 2 on the machine tool side, and a fitting shaft that protrudes from the contact surface 16 and fits into the fitting hole 14 of the tool attachment section 2. A recess 5 having an inclined inner wall surface 4 is provided on the outer peripheral surface of the fitting shaft portion 3, and the tool attachment portion 2 has a fitting hole portion 14.
A threaded hole 17 extending in a direction perpendicular to the axial direction of the threaded rod 21 is inserted into the threaded hole 17 and has a tapered engagement shaft portion 20 at its tip.
0 is screwed so that it can move in and out of the recess 5 of the fitting shaft 3, and the threaded rod 21 is driven in forward and reverse directions, and the tapered engagement shaft 20 is moved into the recess 5 during normal rotation. The attachment 1 is drawn inward by sliding along the inclined inner wall surface 4 of the attachment, and the recess is formed in the shape of a substantially triangular pyramid hole. This is a characteristic feature.

Further, as an embodiment of the present invention, the tool attachment attachment 1 is formed into a hollow cylindrical shape, and within this hollow cylindrical tool attachment attachment, the rotational force transmission part 10 is provided at the base end, and the tool attachment is provided at the distal end. A structure in which a tool drive shaft 6 having a portion 9 is supported is adopted.

(Function) In the tool clamping device of the present invention as described above, in a state where the tapered engagement shaft portion 20 at the tip of the screw rod 21 is retracted into the screw hole 17, the engagement shaft portion 3 of the tool mounting attachment 1 is removed. is fitted into the fitting hole 14 of the tool attachment part 2 on the machine tool side, and the abutted surface 16 on the attachment 1 side is brought into approximate contact with the abutment surface 15 on the tool attachment part 2 side, so that the rotation By driving the screw rod 21 in the normal rotation by the driving means 22 to cause the tapered engagement shaft portion 20 to protrude into the recess 5 and slide along the inclined inner wall surface 4, a so-called wedge effect is created. The fitting shaft portion 3 is pulled inward in the axial direction, and the abutted surface 16 of the tool attachment attachment 1 comes into close contact with the abutment surface of the tool attachment portion 2, and the attachment 1
Further, according to an embodiment of the present invention, the rotational force transmitting portion 10 of the tool drive shaft 6 supported on the attachment 1 is connected to the drive main shaft 29.
automatically linked to.

(Example) An example of the present invention will be described below based on the drawings.

In FIG. 1, 1 is a hollow cylindrical tool attachment, and 2 is a tool post (tool attachment part) on the machine tool side. The tool mounting attachment 1 is coaxially provided with a straight fitting shaft portion 3 having a smaller diameter than other portions at its inner end. A through hole-shaped recess 5 having a tapered inner wall surface 4 is provided in an axially intermediate portion of the outer circumferential surface of the fitting shaft 3, and is perpendicular to the central axis of the fitting shaft 3. The hole is drilled along the central axis _l1 . And in this invention,
The recess 5 is characterized in that it is formed into a substantially triangular pyramidal hole shape, as shown in FIGS. 2 and 3. A tool drive shaft 6 is rotatably supported through bearings 7 and 8 in the attachment 1, and a tool grip, which is a tool mounting portion for gripping a tool T, is provided at the outer end of the tool drive shaft 6. A clutch pawl 1 serving as a rotational force transmitting portion is attached to the inner end of the tool drive shaft 6 that protrudes from the fitting shaft portion 3.
0 is formed. Reference numeral 11 denotes a manipulator grip portion formed on the attachment 1.

The tool post 2 is a fixing member 1 of a machine tool.
It is attached and fixed to 2 with bolt 13,
A fitting hole 14 that can be fitted with the fitting shaft 3 of the attachment 1 is provided on the front side of the tool post 2, and an annular hole is provided on the outer side (inlet side) opening periphery of the fitting hole 14. A contact surface 15 is formed, and an annular contact surface 16 formed on the base end side of the fitting shaft portion 3 of the attachment 1 is brought into contact with this contact surface 15. The tool post 2 also has a screw hole 1 extending in a direction perpendicular to the center axis of the fitting hole 14.
The screw hole 17 is provided so that its inner open end faces the recess 5 of the fitting shaft portion 3 that is fitted into the fitting hole portion 14, and When the abutted surface 16 is in approximate contact with the abutment surface 15 (close to it), the screw hole 1
The center axis _l2 of the recess ₅ is provided so that it is eccentrically inwardly in the axial direction by a slight amount (indicated by e in the figure) with respect to the center axis l1 of the recess 5 (see Figs. 1 and 2). reference). Reference numeral 18 denotes a rotation preventing pin protruding from the annular abutting surface 15 of the tool post 2, and is fitted into a groove 19 formed in the abutted surface 16 that abuts the annular abutting surface 15.

In the threaded hole 17 of the tool post 2, a bolt-like threaded rod 21 having a tapered engagement shaft 20 at its tip inserts the tapered engagement shaft 20 at its tip into the recess 5. The screw rod 21 is screwed so as to be able to move in and out, and the screw rod 21 is driven to rotate in forward and reverse directions by a rotation drive means 22. Note that the tapered engagement shaft portion 20 has an overall diameter smaller than the inner diameter of the recess 5. The rotational drive means 22 includes a cylindrical holder 25 having an engaging recess 24 that can be fitted into the hexagonal head 23 of the screw rod 21 projecting outside the tool post 2, and one end of which is fitted into the holder 25. holder 2 by the key 26.
A drive shaft 27 is coupled to the drive shaft 27 so as not to rotate relative to the drive shaft 5, and the other end (not shown) is rotated in forward and reverse directions via a speed reduction mechanism and a motor, and a drive shaft 27 is connected concentrically between the holder and the drive shaft 27 in the holder 25. It is composed of a buffer spring 28 interposed in a shape.

The tool drive shaft 6 is rotationally driven by a drive main shaft 29 via a clutch mechanism serving as a rotation transmission section.
This clutch mechanism consists of the clutch pawl 10 on the tool drive shaft 6 side, and a clutch pawl 30 formed at the opposite end of the drive main shaft 29 and meshing with the clutch pawl 10. The driving main shaft 29 is movable in the axial direction, and for example, like the rotation driving means 22, the driving shaft and the driving main shaft 29
By connecting the two shafts by a key/keyway means and interposing a buffer spring between both shafts, the drive main shaft 29 rotates integrally with the drive shaft, but independently of this and by interposing a buffer spring between the two shafts. It is designed to be able to move in the axial direction under pressure.

Next, to explain how to use it, the rotation driving means 22 is driven in reverse, and the tapered engagement shaft portion 20 of the threaded rod 21 is inserted into the threaded hole 1 from the inner circumferential surface of the fitting hole portion 14.
7, and in this state, the tool mounting attachment 1 is placed so that its annular abutment surface 16 faces the annular abutment surface 15 of the tool post 2, and the tool post 2 side is inserted into the concave groove 19. It is attached to the tool post 2 so that the rotation stopper pin 18 fits therein. As a result, the fitting shaft 3 on the attachment 1 side fits into the fitting hole 14 of the tool post 2, and the inner opening of the screw hole 17 of the tool post 2 fits into the recess 5 of the fitting shaft 3. The annular contact surface 16 on the attachment 1 side is slightly deviated from the annular contact surface 15 on the tool post 2 side.
It will be in a state close to.

When the rotation driving means 22 is driven in normal rotation in such a state, the forward rotation of the threaded rod 21 causes the tapered engagement shaft portion 20 on the tip side of the screw rod 21 to rotate against the engagement shaft portion 3 located eccentrically with respect to the screw rod 21. While entering the recess 5, it is brought into pressure contact with the tapered inner wall surface 4 in the state shown in FIG. As a result, the fitting shaft portion 3 is pulled inward in the axial direction indicated by the arrow in FIG.
is brought into contact with the annular contact surface 15 of the tool post 2 in surface contact. In this state, normal rotation drive for the screw rod 21 is stopped, but if a torque limiter is installed on the rotation drive means 22 side or a torque motor is used for the motor, the drive stop timing of the screw rod 21 may be delayed. It is desirable to configure the system so that the load can be automatically avoided.

Furthermore, the tool drive shaft 6 supported within the tool mounting attachment 1 is rotated when the tool mounting attachment 1 is attached to the tool post 2.
The drive main shaft 29 and the tool drive shaft 6 are automatically connected via a clutch mechanism consisting of clutch pawls 30 and 10 on both sides, which serve as rotational force transmitting parts. In other words, even if the phases of both clutch pawls 30 and 10 are shifted during occlusion, the clutch pawl 30 of the drive main shaft 29 is aligned with the tool drive shaft 6.
Pushed by the clutch pawl 10 on the side, the clutch pawl 10 moves backward against the buffer spring, and when the two clutch pawls 30, 10 are brought into phase by the rotation of the drive shaft 29, the drive shaft 29 moves forward under the biasing force of the buffer spring. Both clutch pawls 3
0 and 10 will automatically interlock. Therefore, by rotationally driving the drive main shaft 29, the rotational force can be transmitted to the tool driving shaft 6 on the tool mounting attachment 1 side through the clutch mechanism, and the tool gripping tool 9, which is a tool mounting portion, can be rotationally driven. .

When removing the tool mounting attachment 1 from the tool post 2, the screw rod 21 is reversely driven by the rotary movable means 22, and the tapered engagement shaft portion 20 on the tip side is moved out of the recess 5 of the fitting shaft portion 3. the attachment 1
The fitting shaft portion 3 may be pulled out from the fitting hole portion 17 of the tool post 2 by pulling outward.

In the above-described embodiment shown in FIG.
As shown in the illustrated embodiment, a tapered intermediate fitting shaft portion 31 may be interposed between the fitting shaft portion 3 and the annular abutted surface 16. Of course, in this case, it is necessary to provide a tapered intermediate fitting hole portion corresponding to this intermediate fitting shaft portion 31 on the tool post 2 side.

In the present invention, the recess into which the tapered engagement shaft portion 20 of the screw rod 21 engages is shown in FIGS. 2 and 3.
As shown in the embodiment shown in the figure, since the hole is formed into a substantially triangular pyramid-shaped hole that narrows in the middle, there is a line contact at two locations (indicated by a and b in the figure) on the substantially triangular inner wall surface 32 of this hole 5. Therefore, screw rod 21
Due to the axial force of The pressure contact force against the inner wall surface 32 is dispersed, the wear of the inner wall surface 32 is reduced, a more stable pulling force is applied to the fitting shaft portion 3, and the attachment 1 is not subjected to circumferential load during cutting. Even if the engagement shaft 20 is held between points a and b, and there is no relative displacement between the engagement shaft 20 and the attachment 1, the engagement shaft 20 does not touch the inner wall surface of the recess 5 excessively. Therefore, when removing the attachment 1 from the tool post 2, the screw rod 21 can be easily reversed. In this case, if the recess 5 is formed into a conical hole 33 as shown in FIG. is formed, so that when the attachment 1 receives a load in the circumferential direction due to cutting resistance, the two are relatively displaced in the direction of absorbing the gap 35, and this causes the engagement shaft portion 20 to move along the dashed-dotted line. As shown in , there is a risk that the screw may bite into the inner wall surface 34 of the recess excessively, and an excessively larger torque may be required when the screw rod 21 is rotated in the reverse direction than when it is rotated in the normal direction.

(Effects of the invention) According to the tool clamping device of the present invention, the tool mounting attachment is not clamped by the tensile force of a spring as in the conventional device, but the tapered engagement of the tip of the screw rod attached to the tool mounting portion side is used. The shaft part is engaged and slid into contact with the inclined inner wall surface of the recess on the attachment side, and its wedge effect draws the attachment inward and clamps it, so it can be clamped extremely strongly. Therefore, it can be safely used as a clamping device for a tool attachment in a machine tool that performs heavy cutting or machining with a large overhang.

Further, according to the present invention, the tool mounting attachment is formed into a hollow cylindrical shape, and within the hollow cylindrical tool mounting attachment, the tool has a rotational force transmitting portion at its base end and a tool mounting portion at its distal end. Since the drive shaft is supported by a shaft, when the above attachment is clamped to the tool post, the tool drive shaft is automatically accurately connected to the drive main shaft via the rotational force transmission part, and is also strongly clamped. Since the tool drive shaft is supported by the attachment, it is possible to reliably prevent the shaft runout of the cutting tool attached to the tool attachment portion at the tip thereof, thereby improving machining accuracy.

Furthermore, as shown in the embodiments, the clamping device of the present invention can be easily applied to a rotary tool mounting attachment equipped with a tool drive shaft, making it possible to perform a wide variety of tooling. In addition, even when using a rotary tool attachment in this way, since the rotary tool attachment is fixed to the tool attachment part (tool post 2 in the example) on the machine tool side that does not rotate, automatic tool change is not possible. There is no need to stop the tool drive shaft in a fixed position (orientation) during work, and the tool drive system can be easily controlled and implemented at low cost. It can also be used for both rotating tools and fixed tools.

Further, the tool clamping device of the present invention has a small number of parts and a simple structure, so it can reduce manufacturing costs and is extremely effective in terms of durability.

In particular, in the present invention, the recess into which the tapered engagement shaft of the threaded rod engages is formed into a medium-taper, approximately triangular pyramid-shaped hole, so cutting resistance in the circumferential direction is applied to the tool mounting attachment. Even in this case, the engagement shaft portion does not bite into the inner wall surface of the recess excessively, and the screw rod can be easily reversed when the attachment is removed from the tool post.

Further, according to an embodiment of the present invention, the tool mounting attachment is formed into a hollow cylindrical shape, and the hollow cylindrical tool mounting attachment has a rotational force transmitting portion at its base end and a tool mounting portion at its distal end. When the attachment is clamped to the tool post, the tool drive shaft is automatically and accurately connected to the drive main shaft via the rotational force transmission part, and the Since the tool drive shaft is supported by the attachment clamped on the attachment, it is possible to reliably prevent the axial runout of the cutting tool attached to the tool attachment portion at the tip of the attachment, thereby improving machining accuracy.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view of a tool clamp device showing an embodiment of the present invention, Fig. 2 is a partially sectional plan view showing the positional relationship between the tapered engagement shaft of the screw rod and the recess, and Fig. 3. 4 is a perspective view showing another embodiment, and FIG. 5 is a diagram for explaining the operation of the present invention. 1... Attachment for mounting tools, 2...
Tool post (tool attachment part), 3... Fitting shaft part, 4... Tapered side wall surface (sloped inner wall surface),
5... Recess, 6... Tool drive shaft, 9... Tool attachment part, 10... Rotational force transmission part, 14... Fitting hole part,
15...Abutting surface, 16...Abutted surface, 17...Threaded hole, 20...Tapered engagement shaft portion, 21...Threaded rod.

Claims (1)

[Claims for Utility Model Registration] 1. A tool mounting attachment has a contact surface that contacts the contact surface of a tool mounting portion on the machine tool side, and a contact surface that protrudes from the contact surface and that fits into the tool mounting portion. A fitting shaft portion that fits into the hole portion is provided, a recess having an inclined inner wall surface is provided on the outer circumferential surface of the fitting shaft portion, and the tool attachment portion is provided with a recess that has an axial direction of the fitting hole portion. A screw hole extending in orthogonal directions is provided through the screw hole, and a screw rod having a tapered engagement shaft portion at its tip is inserted into the screw hole so that the engagement shaft portion protrudes and retracts from the recess of the fitting shaft portion. The screw rod is screwed as much as possible, and the screw rod is driven in forward and reverse directions.
The tool clamp device is configured to draw the attachment inward by pushing the tapered engagement shaft into the recess and sliding it along the inclined inner wall surface of the recess during normal rotation, the tool clamping device comprising: A tool clamping device characterized by having a substantially triangular pyramidal hole shape. 2. The tool mounting attachment has a hollow cylindrical shape, and within this hollow cylindrical tool mounting attachment, a tool drive shaft having a rotational force transmission section at the base end and a tool mounting section at the distal end is supported. A tool clamping device according to claim 1 of the utility model registration claim.