JP2812677B2 - Clamp mechanism for indexable inserts - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a throw-away tip clamping mechanism for fixing a throw-away tip to a tool holder using a clamp piece.

[0002]

2. Description of the Related Art Among cutting tools for performing a cutting operation by fixing a throw-away tip to the tip of a tool holder, FIG.
As shown in FIG. 1, a type in which a throw-away tip (hereinafter, abbreviated as a tip) 1 is fixed to a tool holder 4 by an eccentric pin 2 and a clamp piece 3 is known. That is, the tip corner of the tool holder 4 is cut out to form a chip mounting seat 5 having a bottom surface 5a and a side surface 5b, and a screw hole 6 for fixing a sheet is formed in the bottom surface 5a. A screw 2a provided with an eccentric pin 2 at the top is screwed into the screw hole 6, and a sheet 7 is fixed.
The chip 1 is mounted on the chip. On the other hand, a screw hole 4a is formed in the tool holder 4 on the base end side from the tip mounting seat 5, and a screw hole 3a is formed in the clamp piece 3 in a direction opposite to the screw hole 4a of the tool holder 4. A clamp screw 8 having a reverse screw mechanism is provided in these screw holes 3a and 4a.
Is to be screwed.

Then, the eccentric pin 2 is rotated in the mounting hole 1a of the chip 1, and the inner peripheral surface of the mounting hole 1a is pressed toward the side surface 5b of the chip mounting seat 5 by the protrusion 2b. Further, the clamp screw 8 is screwed into the screw holes 3a, 4a and tightened to lower the clamp piece 3 disposed on the base end side of the chip mounting seat 5, and the pressing surface formed at the distal end of the clamp piece 3 The chip 1 is fixed to the chip mounting seat 5 by pressing the upper surface of the chip 1 toward the bottom surface 5a of the chip mounting seat 5 with 3a. However, in this clamp mechanism, since the chip 1 is fixed by the two-step operation using the eccentric pin 2 and the clamp piece 3, it takes time and effort to mount the chip 1 and the operability is poor. Because of the large number of parts, there is a problem that it takes time to manage the parts.

[0004] Therefore, as a tip clamping mechanism which solves the above-mentioned problems, a tip clamping mechanism as shown in FIG. 14 is used. This is because a clamp fixing hole 11 having a screw portion 11a is provided on the base end side of the tool holder 9 from the tip mounting seat 10.
Are formed at an angle of θ ′ with respect to the axis of the screw hole 12 for fixing the seat. Then, a counterbore hole 11b having a diameter larger than that of the screw portion 11a is provided above the clamp fixing hole 11.
Is formed, and the short side portion 13a of the clamp piece 13, which is bent in a "-" shape in cross section, is inserted into the counterbore hole 11b. At the distal end of the long side portion 13b of the clamp piece 13, a pressing portion 14 formed in a curved surface and a projection 15 on its base end side are formed. A bolt hole 16 is formed in the short side 13 a of the clamp piece 13 at a position facing the clamp fixing hole 11. A clamp screw 17 having a reverse screw mechanism is screwed into the bolt hole 16 and a screw portion 11a of the clamp fixing hole 11 in which a screw in a direction opposite to the bolt hole 16 is formed.
Moves along the clamp fixing hole 11. Therefore, the chip 18 is pressed by the pressing portion 14 in the direction of the bottom surface 10a, and the protrusion 15 presses the inner peripheral surface of the mounting hole 15a toward the side surface 10d.
Fixed to

[0005]

According to the above-mentioned conventional clamping mechanism, the upper surface and the side surface of the tip 18 are pressed by the mounting seat 10 only by operating the clamp piece 13, and the tip 18 is easily fixed to the tool holder 10. Is done. However, the pressing portion 14 and the projection 15 formed at the tip of the clamp piece 13
Since the corners of the cutting tool press the tip 18 of cemented carbide or the like with a small contact area, when this cutting tool is used for a long time, the contact part is worn and loosened, requiring additional tightening. Eventually, there was a problem that the clamp piece 13 itself became unusable. The optimal clamping force that the pressing portion 14 and the projection 15 of the clamp piece 13 can give to the chip 18 is determined by the axial center of the clamp fixing hole 11,
Since it is determined by the angle θ ′ formed with the screw hole 12 for fixing the sheet, it is necessary to machine the hole 11 for fixing the clamp with high dimensional accuracy, which leads to an increase in the unit price of the tool as a whole. Has become.

An object of the present invention is to solve the above-mentioned problems of the conventional clamp mechanism.

[0007]

A first aspect of the present invention.
The described tip clamping mechanism has a tip mounting seat formed on the top surface of the tip of the tool holder, and presses the clamp piece by pressing means to press and fix the throw-away tip against the bottom and side surfaces of the tip mounting seat. In the clamp mechanism of the indexable insert, an inclined surface is formed on the upper surface of the tool holder and gradually inclined toward the lower surface side as the distance from the tip mounting seat side to the base end side of the tool holder increases. inclined surface abutting the sliding surface of the tool holder is formed on the end side, the projection which engages in a hole of the throw-away tip to the pressing portion of the clamping piece is formed, the clamp
For the piece and the tool holder, face the tip mounting seat of the clamp piece.
Locking parts are formed to prevent the movement of
The piece slides while its locking part contacts the locking part of the tool holder
To guide the protrusion into the hole of the throw-away tip.
It is characterized in that it has a so that. Further, in the tip clamping mechanism, an elastic member may be mounted between the clamp piece and the tool holder to urge the clamp piece in a direction to separate the clamp piece from the tool holder.

[0008]

According to the tip clamping mechanism of the first aspect of the present invention, when the clamp piece is pressed by the pressing means, the clamp is closed .
When the locking part of the ramp piece contacts the locking part of the tool holder,
Slides down, the projection guides the direction of movement.
Securely engage the hole of the chip is de, and is a sliding surface and the inclined surface of the tool holder engaged with each other in the clamping piece, the clamping piece is moved along the inclined surface with respect to the tool holder.
Thus, the clamp piece presses the chip toward both the bottom surface and the side surface of the chip mounting seat. When the pressing means is loose, contact of the locking portion between the clamp piece and the tool holder prevents lateral movement of the clamp piece beyond a predetermined range, and furthermore, movement of the clamp piece in the direction of the chip mounting seat. Since the range is regulated, the protrusion is prevented from deviating from the range of the hole of the chip. Further, when the pressing means is loose, the clamp piece is urged upward by the elastic force of the elastic member, and is clamped by the pressing means and the elastic member, so that the vertical and horizontal swinging is prevented.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a clamp mechanism for a throw-away tip according to the present invention will be described with reference to FIGS. In FIG. 1, a bottom surface 20 is formed at a corner of the upper surface 19 a of the tool holder 19 on the distal side (hereinafter, the left is referred to as the distal side and the right is referred to as the proximal side in the figure).
The chip mounting seat 20 formed by cutting out the chip mounting seat 20 is formed on the chip mounting seat 20, and a plate-shaped chip 21 having a mounting hole 21a is placed on the chip mounting seat 20 via a sheet 22. A screw hole 20c for fixing the seat, which is perpendicular to this surface, is formed in the bottom surface 20a of the chip mounting seat 20.
Is formed with a through hole 22a whose central upper end is tapered. Then, the sheet 22 is formed by screwing a screw member 23 having a conical head through the through hole 22a into the screw hole 20c for fixing the sheet.
It is fixed to the chip mounting seat 20.

On the other hand, an inclined surface 19b is formed on the upper surface 19a of the tool holder 19 on the base end side of the chip mounting seat 20 toward the lower surface as the distance from the chip mounting seat 20 increases, and the inclined surface 19b is fixed to the seat. Screw hole 20c
Has an acute angle θ with respect to the axis. A concave portion 19c is formed continuously from the inclined surface 19b to the base end side, and a locking wall 19d (locking portion) parallel to the axis of the seat screw hole 20c is formed in the concave portion 19c. A clamp fixing hole 24 having a screw portion 24a is formed between the inclined surface 19b of the tool holder 19 and the tip mounting seat 20, and a larger counterbore is provided above the clamp fixing hole 24. A hole 24b is formed. Tool holder 1
A clamp piece 25 is placed on the upper surface 19a of the plate 9. As shown in FIGS. 3 and 4, the clamp piece 25 has an L-shape in a side view and a rectangular shape with an acute end in a plan view. A clamp screw insertion hole 25a having an oval cross section extending along the longitudinal direction of the clamp piece 25 is formed substantially at the center of the clamp piece 25, and a lower portion of the clamp screw insertion hole 25a is formed in the lower part of the clamp screw insertion hole 25a. Is a counterbore hole 25b having substantially the same diameter as the counterbore hole 24b of the tool holder.
Are formed. As shown in FIG. 3, the counterbore hole 25b
Position of the axis O ₁ is formed as the base end side than the position of the axis O ₂ of the clamp screw insertion hole 25a deviates distance L _0.

The lower surface of the tip of the clamp piece 25 is
A pressing surface 26 is in contact with the upper surface of the first surface, and a projection 27 is formed so as to protrude from the pressing surface 26 on the base end side. The base end side surface of the projection 27 is an arc-shaped convex surface 27a in plan view as shown in FIG. The lower surface 28 following the projection 27 of the clamp piece 25 is located above the pressing surface 26 in FIG. A locking portion 29 protruding downward is formed at the base end of the clamp piece 25. The inside of this corner is formed on a sliding surface 29a having an inclination angle corresponding to the inclination surface 19b of the tool holder 19, and The inclined surface 1 of the tool holder 19
The inner surface connected to 9b is a locking wall 29b orthogonal to the lower surface 28. The clamp piece 25 is inserted into the screw portion 24 by loosely inserting the clamp screw 30 from above the clamp screw insertion hole 25a.
It is attached to the tool holder 19 by being screwed into a. Around this clamp screw 30, a coil spring (elastic member) 31 having an outer diameter slightly smaller than the inner diameter of the counterbore holes 24b, 25b is provided.
b, 25b.

In the state where the clamp screw 30 is loosened as shown in FIG.
5 is separated from the upper surface 19a of the tool holder 19, and the clamp piece 25 is moved from above and below by the head 30a of the clamp screw 30.
And the coil spring 31. At this time, the clamp piece 25 is prevented from moving toward the distal end by the contact between the locking walls 29b and 19d. Then, in this state, the axis O ₁ of the counterbore hole 25b of the clamp piece 25 is L ₁ closer to the base end than the axis O ₃ of the counterbore hole 24b of the tool holder 19.
Distance m of the distance l and the axis O ₃ and engaging wall 19d of the axis O ₁ and the engaging wall 29b so as to be offset only is set. In addition, the position of the protrusion 27 is set in the state of FIG.
The chip 21 is set so as to be kept at a fixed upper position facing the mounting hole 21a of the chip 21 mounted on the chip 21.

As described above, in this state, the clamp piece 2
Since the axis O ₁ of the counterbore 25b of 5 are shifted by L ₁ proximal to the axis O ₃ of the countersunk hole 24b of the tool holder 19, the coil spring 31 is bent proximally toward the upper Due to the restoring force, the clamp piece is urged toward the distal end. Accordingly, since the locking walls 29b and 19d are always in contact, the lateral movement of the clamp piece 25 is prevented. Hereinafter, the clamp piece 25 is the chip 2
The procedure for pressing and fixing 1 will be described with reference to FIGS.

Usually, only the operation of exchanging the chip 21 is required, so that it is not necessary to move the clamp piece 25 upward any more, so that the clamp screw 30 is not loosened further in the state shown in FIG. A detent may be provided. First, the clamp screw 30 is screwed in from the state shown in FIG. At that time, the axis O ₁ , O ₃
Since the members are still displaced from _each other by the distance of L1, the clamp piece 25 is urged toward the distal end by the coil spring 31, and the contact between the locking walls 29b and 19d continues.
Further, the clamp piece 25 is a head 30 of the clamp screw 30.
a and the coil spring 31, the clamp piece 25 does not swing laterally with the rotation of the clamp screw 30. Therefore, the clamp piece 25 is fixed to the locking walls 29b, 19
d moves straight down, guided by the contact of d, and clamp piece 2
5 are provided on the chip 21 as shown in FIGS.
Without moving onto the upper surface of the mounting hole 21a.

When the clamp screw 30 is further screwed in this state, as shown in FIG. 8, the locking walls 29b, 1
The sliding surface 29a and the inclined surface 19b, which are continuous with 9d, come into contact with each other to apply resistance to the base end side of the clamp piece 25 and prevent the base piece from descending. When the clamp screw 30 is further screwed in, as shown in FIG. 9, only the distal end side is lowered, the clamp piece 25 is inclined, and the pressing surface 26 of the clamp piece 25 is brought into line with the sliding surface 29a and the inclined surface 19b in line contact. It contacts the upper surface of the chip 21. Then, when the clamp screw 30 is screwed in and the clamp piece 25 is further pressed downward, the base end side of the clamp piece 25 moves obliquely along the inclined surface 19b, returns to surface contact, and the locking walls 29b, 19d are separated. As the projection 27 gradually approaches the inner wall of the mounting hole 21a, the distance between the axes O ₁ and O ₃ also increases, and the coil spring 3
One bend is even greater.

Then, as shown in FIG.
With the a and the inclined surface 19b engaged in surface contact, the pressing surface 26 of the clamp piece 25 and the convex surface 27a of the projection 27 abut on the upper surface of the chip 20 and the inner wall of the mounting hole 21a. The chip 21 is pressed toward the bottom surface 20a of the chip mounting seat 20 and simultaneously pressed toward the side surface 20b to be fixed. In the above case, the ideal case where the dimensions of the clamp piece 25 match the dimensions of the chip 21 has been described. However, the clamp of the present application is also effective when the type of the chip 21 is different. That is, FIG. 11 occurs when the tip 21 is large or the like, and the lower surface of the clamp piece 25 is not parallel to the upper surface of the tool holder 19 and the clamp piece 25
Is raised, so that the sliding surface 29a and the inclined surface 1
9b are engaged with each other by line contact. Even in this state, the bent coil spring 31 urges the clamp piece 25 in the direction toward the chip mounting seat 20.
The engaged state is sufficiently maintained, and the chip 21 is securely fixed. FIG. 12 shows a situation that occurs when the tip 21 is small. Even when the base end of the clamp piece 25 is lowered and the sliding surface 29a is in line contact with the lower portion of the inclined surface 19b, the tip 21 is securely fixed. ing.

On the other hand, when removing the tip 21 from the tool holder 19, the process reverse to the above proceeds by loosening the clamp screw 30. That is, the clamp piece 25
In the state in which the tip is urged toward the distal end and the upper side by the restoring force of the coil spring 31, the tip first moves obliquely along the inclined surface 19b, and the pressing of the chip is released. Next, locking wall 2
When the members 9b and 19d come into contact with each other, they move upward, the sliding surface 29 separates from the inclined surface 19b, and returns to the state shown in FIG. Even in this release process, the clamp piece 25
Is clamped from above and below by the head 30a of the clamp screw 30 and the coil spring 31, and the locking walls 29b and 19d are in contact with each other by the bias of the coil spring 31, so that the clamp piece 25 always rises in a constant posture. And good operability.
In the state shown in FIG. 2, since the projection 27 is located above the chip 21, the chip 21 can be taken out from the side and the chip 21 can be replaced.

As described above, since the clamp piece 25 is pressed downward by the clamp screw 30 and moved to press the chip 21 against the bottom surface 20a and the side surface 20b of the chip mounting seat 20, the chip 21 is fixed. , A normal cutting operation can be performed, and the coil spring 31 has a structure that sufficiently holds the engagement state between the clamp piece 25 and the tool holder 19. Since it can be manufactured without processing with high dimensional accuracy like a conventional tool holder, the product price of a cutting tool can be reduced.

[0019]

The inclined surface 19b of the tool holder 19 is
The angle θ with respect to the normal to the bottom surface 20a of the seat 20 is 30
When the clamp piece 25 is formed so as to have a range of {60}, the clamp piece 25 can apply a uniform clamping force to the chip 21 and fix it. The tip 21 has an appropriate shape such as a polygon or a circle, and the tip mounting seat 20 is formed in accordance with each shape.

[0021]

According to the first aspect of the present invention, there is provided a tip clamping mechanism in which the upper surface of the tool holder is gradually inclined toward the lower surface as the distance from the tip mounting seat side to the base end side of the tool holder increases. surface is formed on the lower surface of the clamping piece, the inclined surface abutting the sliding surface of the tool holder is formed on the base end side, the projection which engages in a hole of the throw-away tip to the pressing portion of the clamping piece is formed, the clamping piece And tool holder
Prevents the clamp piece from moving toward the tip mounting seat
Locking portions are formed, and the clamp pieces are
Part slides while abutting against the locking part of the tool holder.
Induced protrusions in the hole of the lower tip
Therefore, when the pressing means is loose, contact of the locking portion between the clamp piece and the tool holder prevents lateral movement of the clamp piece beyond a predetermined range, and furthermore, movement of the clamp piece in the direction of the chip mounting seat. Since the range is regulated, the projection is prevented from deviating from the range of the hole of the chip, and when the clamp piece is next pressed by the pressing means, the clamp piece is locked.
The part is guided by the locking part of the tool holder and descends, and the protrusion is smoothly inserted into the hole of the chip. Further, the tip clamping mechanism is provided with an elastic member for urging the clamp piece in a direction to separate the clamp piece from the tool holder between the clamp piece and the tool holder. The clamp piece is urged upward by the resilience of, and is held by the pressing means and the elastic member,
Up, down, left, and right sideswing is prevented.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a first embodiment of a clamp mechanism for a throw-away tip of the present invention, showing a state where the throw-away tip is fixed to a tool holder.

FIG. 2 is a cross-sectional view showing a first embodiment of a clamp mechanism for a throw-away tip according to the present invention, showing a state where a clamp piece is separated from an upper surface of a tool holder.

FIG. 3 is a plan view of a clamp piece according to the first embodiment of the clamp mechanism for a throw-away tip of the present invention.

FIG. 4 is a cross-sectional view of a clamp piece, showing a first embodiment of a clamp mechanism for a throw-away tip of the present invention.

FIG. 5 is a plan view showing a first embodiment of the throw-away tip clamping mechanism of the present invention, and is a virtual view showing an engagement state between the throw-away tip and the clamp piece.

FIG. 6 is a longitudinal sectional view showing the first embodiment of the clamp mechanism of the throw-away tip of the present invention and virtually showing an engagement state between the throw-away tip and the clamp piece.

FIG. 7 is a cross-sectional view illustrating a first step of a method of fixing a throw-away tip to a tool holder using a clamp piece according to a first embodiment of the present invention; is there.

FIG. 8 is a cross-sectional view illustrating a second embodiment of a method of fixing a throw-away tip to a tool holder using a clamp piece, illustrating a first embodiment of a throw-away tip clamping mechanism of the present invention. is there.

FIG. 9 is a sectional view showing a third embodiment of the method for fixing the throw-away tip to the tool holder by using a clamp piece, showing the first embodiment of the throw-away tip clamping mechanism of the present invention. is there.

FIG. 10 is a cross-sectional view showing a fourth embodiment of the method for fixing the throw-away tip to the tool holder using a clamp piece, showing the first embodiment of the throw-away tip clamping mechanism of the present invention. is there.

FIG. 11 is a cross-sectional view showing a state where the clamp piece is attached to the tool holder at an angle and the sliding surface of the clamp piece and the inclined surface of the tool holder are in line contact.

FIG. 12 is a cross-sectional view showing a state where the clamp piece is attached to the tool holder at an angle and the sliding surface of the clamp piece and the inclined surface of the tool holder are in line contact with each other.

FIG. 13 is a sectional view showing a conventional clamp mechanism.

FIG. 14 is a sectional view showing another conventional clamping mechanism.
You.

[Explanation of symbols]

Reference Signs List 19 Tool holder 19a Upper surface of tool holder 19b Inclined surface of tool holder 19d Locking wall of tool holder 20 Chip mounting seat 20a Bottom surface of chip mounting seat 20b Side surface of chip mounting seat 21 Tip (throw-away tip) 24a Screw hole 25 Clamp Piece 25a Clamp screw insertion hole 27 Projection of clamp piece 29 Clamp piece locking part 29a Clamp piece sliding surface 29b Clamp piece locking wall 30 Clamp screw 31 Coil spring (elastic member) O ₁ Shaft center of counterbore hole of clamp piece O ₂ Clamp screw the axis of the countersunk hole in the axis O ₃ toolholder bore

Continuation of the front page (56) References JP-A-58-59705 (JP, A) JP-A-60-114403 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B23B 27 / 16

Claims (2)

(57) [Claims] A tip mounting seat is formed on a top surface of a tip end portion of a tool holder, and a clamp piece is pressed by pressing means to press and fix the throw away tip against the bottom and side surfaces of the tip mounting seat. In the clamping mechanism, an inclined surface is formed on the upper surface of the tool holder, and is gradually inclined toward the lower surface side as the distance from the tip mounting seat side to the proximal end side of the tool holder is increased. A sliding surface is formed on an end side to be in contact with the inclined surface of the tool holder, a projection is formed on a pressing portion of the clamp piece to engage with a hole of the throw-away tip, and the clamp is formed on the clamp piece and the tool holder. Piece
Locking parts that prevent movement toward the tip mounting seat
The clamp piece has a locking portion with a tool holder.
Sliding while contacting the locking part of
A mechanism for clamping a throw-away tip , wherein the projection is guided into a hole of the tip. 2. The thrower according to claim 1, wherein an elastic member for urging the clamp piece in a direction to separate the clamp piece from the tool holder is mounted between the clamp piece and the tool holder. Away tip clamping mechanism.