JP2548030Y2 - Tip clamp mechanism - Google Patents

Description

[Detailed description of the invention]

[0001]

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

[0002]

2. Description of the Related Art Conventionally, as a clamping mechanism of this kind, for example, as shown in FIG. 10, a clamp piece 3 is disposed above a tip mounting seat 2 provided on the upper surface side of the tip end of a tool holder 1. A reverse thread 5a of a clamp screw 5 screwed into the female thread 4 of the tool holder 1 is screwed into the thread 3a provided on the rear end side of the block 3, and the clamp screw 5 is connected to the tool holder 1 The clamp piece 3 is made to approach the bottom surface 2a of the chip mounting seat 2 by tightening toward the lower surface side of the chip mounting surface 2 and thereby the throw-away chip (hereinafter, chip) mounted on the bottom surface 2a of the chip mounting seat 2 via the sheet 6 There is known a configuration in which a pressing member 7 is sandwiched between a pressing surface 3b formed on the lower surface of the distal end portion of the clamp piece 3 and a bottom surface 2a of the chip mounting seat 2.

[0003] In the tip clamp mechanism having the above-described structure, the screwing direction of the clamp screw 5 is particularly set in the tip mounting seat 2.
10 is inclined at an acute angle θ ° with respect to a direction orthogonal to the bottom surface 2a of the tip mounting seat 2 with the clamping operation of the clamp screw 5 described above. ) Is given. Therefore, when the tip 7 is clamped, the projection 3c formed on the lower surface side of the distal end portion of the clamp piece 3 engages with the inner peripheral surface of the mounting hole 7a, and the tip 7 is drawn back to the tip mounting seat 2. Accordingly, the chip 7 is pressed against the wall surface 2b of the chip mounting seat 2, and the rearward movement of the chip mounting seat 2 is prevented.

[0004]

In the above-described conventional tip clamp mechanism, since the moving direction of the clamp piece 3 is limited to the axial direction of the clamp screw 5, the pressing surface 3b of the clamp piece 3 and the tip 7 Changes with the error of the inclination angle θ of the axis of the clamp screw 5. In particular, when the inclination angle θ becomes large, the tip of the clamp piece 3 is inclined obliquely with respect to the chip 7 so that the tip of the pressing surface 3b (the left end in FIG. 10) and the portion near the tip of the upper surface of the chip 7 May come into strong line contact. In this case, as shown in FIG. 11, a force for pressing the chip 7 against the bottom surface 2a of the chip mounting seat 2 (hereinafter, referred to as a vertical clamping force) is used. 2 tip side (hatched part in the figure)
Uniform vertical clamping force cannot be obtained due to large deviation.
When the tip 7 is used in such a state where the longitudinal clamping force is deviated in this manner, as shown in FIG. 12, the synergistic effect of the longitudinal clamping force P of the tip 7 and the cutting resistance F applied to the cutting edge 8 causes The rear end of the tip 7 rises upward from the initial position indicated by the two-dot chain line, and the cutting edge 8 moves to the side where the work W is cut into the work W, thereby causing an error δ in the processing diameter of the work W. In particular, in the case of profile cutting in which the cutting amount of the cutting edge 8 fluctuates, the floating amount of the chip 7 constantly changes due to the fluctuation of the cutting resistance F accompanying the fluctuation of the cutting amount, and There was also a risk of loss.

Further, in the above-described chip clamping mechanism, as shown in FIG. 13, since the distance e from the tip of the clamp piece 3 to the cutting edge of the tip is short, the chip C easily interferes with the tip side of the clamp piece 3. Accordingly, there is also a disadvantage that the distal end of the clamp piece 3 is damaged and abrasion tends to progress early.

The present invention has been made under such a background, and even if a machining error occurs in a tool holder, a chip, or the like, the vertical clamping force applied to the chip can be uniformly held, and the clamping can be performed. It is an object of the present invention to provide a tip clamp mechanism that can also suppress damage and premature wear of a leading end of a bridge.

[0007]

In order to solve the above-mentioned problems, the present invention is directed to an upper surface of a tool holder, which is gradually inclined toward a lower surface of the tool holder as the distance from the tip mounting seat to the rear end of the tool holder increases. While forming the inclined surface, a sliding surface that contacts the inclined surface is formed on the lower surface side of the clamp piece, and the pressing surface of the clamp piece is formed separately from the protrusion.
A convex curved surface is formed adjacent to the vicinity, and the protrusion and the mounting hole
At least a part of both engagement surfaces is
The angle of the tip mounting seat tip side to the bottom is 90 degrees or less.
It forms so that it may become .

[0008]

According to the invention, first, the clamp piece is pressed against the chip mounting seat, whereby the sliding surface of the clamp piece and the inclined surface of the tool holder come into contact with each other, and the sliding surface moves on the inclined surface. Therefore, the clamp piece is given a movement toward the rear end side of the tool holder in addition to the movement toward the bottom side of the tip mounting seat, whereby the tip comes into contact with the pressing surface of the clamp piece and the bottom side of the tip mounting seat. At the same time, the projection of the clamp piece engages with the inner peripheral surface of the mounting hole of the chip, and the chip is drawn toward the rear side of the chip mounting seat. In addition, the pressing surface is located near the protrusion separately from the protrusion.
Formed adjacent to the fitting surface of both the projection and the mounting hole.
At least a part of the tip
Formed so that the angle on the tip side of the top mounting seat is 90 degrees or less
So that the tip of the tip is
Prevents protrusions from coming off from mounting holes when drawing
Is done. In this case, since the pressing surface of the clamp piece is formed in a convex curved shape and is adjacent to the vicinity of the pressing surface , the chip is clamped in a state where the clamp piece is inclined.
The pressing surface of the clamp piece touches the chip
Touch Then, the contact of the tip of the clamp piece is prevented.
You. Therefore, the chip and the pressing surface come into contact with each other in the vicinity of the mounting hole formed substantially in the center of the chip, and a substantially uniform longitudinal clamping force acts on the chip over the entire surface. Furthermore, pressing
Since the surface is formed near the protrusion , the tip of the tip
With the conventional tip clamp mechanism that positively pressed the side
In comparison, the distance from the tip of the clamp piece to the center of the protrusion can be shortened.Therefore, the distance from the cutting edge to the tip of the clamp piece when the chip is clamped is set large to avoid damage to the tip of the clamp piece due to chips. it can.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. The same components as those of the above-described conventional example are denoted by the same reference numerals, and description thereof will be omitted.

In FIGS. 1 to 3, reference numeral 10 denotes a tool holder. The tool holder 10 is formed in a columnar shape having a square cross section, and a tip 7
The chip mounting seat 11 to which is mounted is formed. The tip mounting seat 11 includes a diamond-shaped bottom surface 11a facing upward from the tool holder 10 and two side surfaces 11b standing along two sides of the bottom surface 11a (see FIG. 3).
A rhombic flat sheet 12 is placed on the bottom surface 11 a and fixed with bolts 13. In the following description, the end of the chip mounting seat 11 in the direction of arrow A in FIG. 3 is treated as the front end side of the chip mounting seat 11 and the end of the chip mounting seat 11 in the direction of arrow B is regarded as the rear end side.

On the other hand, above the chip mounting seat 11, a clamp piece 1 extending diagonally on the chip mounting seat bottom surface 11a.
4 is provided, and is detachably connected to the tool holder 10 by a clamp bolt 16 inserted into a bolt hole 15 at an intermediate portion in the longitudinal direction.

As shown in more detail in FIGS. 4 and 5, on the lower surface of the distal end portion of the clamp piece 14, a pressing surface 1 projecting somewhat lower than the lower surface 14a of the central portion of the clamp piece 14 is provided.
7 is formed, and a projection 18 projecting toward the chip mounting seat 11 is formed at the center of the pressing surface 17. The pressing surface 17 is formed in a shape of a convex curved surface that extends downward from the both ends in the longitudinal direction toward the center of the clamp piece 14 and gradually curves downward with a radius of curvature R1 from the clamp piece 14. The protrusion 18 is formed in a columnar shape having an axis in a direction orthogonal to the lower surface 14a of the central portion of the clamp piece 14, and the tip portion 18a has a convex curved surface curved with a radius of curvature R2 over the entire circumference. Is formed.
Further, the outer diameter d of the projection 18 is set to be somewhat smaller than the inner diameter D (see FIG. 2) of the mounting hole 7a formed in the chip 7, and specifically, 1 mm from the inner diameter D of the mounting hole 7a.
It is set to a small value. Accordingly, as shown in FIG. 2, the engaging surface of the impact force 18 and the mounting holes 7a, i.e., the protrusion 1
8 and the rear end of the inner peripheral surface of the mounting hole 7a.
Is a chip with respect to the bottom surface 11a of the chip mounting seat 11.
The angle of the tip of the mounting seat 11 is set to 90 degrees or less.
I have.

As shown in more detail in FIG. 5, the range in which the pressing surface 17 is formed is the thickness t occupied by the projection 18 in the chip pulling direction (corresponding to the outer diameter d of the projection 18 in the illustrated example). Is limited to a range that does not exceed t from the center point P ₀ of the projection 18 in the drawing direction of the chip 7 and in the opposite direction. Incidentally, in the illustrated example, both ends of the pressing surface 17 are separated from the center point P ₀ of the projection 18 by 0.5t, ie, the pressing surface 1
7 are determined so that both ends in the longitudinal direction of the clamp piece coincide with the projections 18. Here, the pulling direction of the chip 7 refers to a direction from the front end side to the rear end side of the chip mounting seat 11, and in the case of this embodiment, from the front end side in the longitudinal direction of the clamp piece 14 to the rear end. Coincides with the direction toward the side.

The bolt hole 15 of the clamp piece 14 is formed in a long hole shape extending in the longitudinal direction of the clamp piece 14 so as to allow the clamp piece 14 to move in the longitudinal direction within a certain range. ing. A tapered portion 15 a is formed at the lower end of the bolt hole 15 so as to gradually increase in diameter toward the lower end of the bolt hole 15.
Further, as shown in FIGS. 1 and 2, the rear end of the clamp piece 14 is bent toward the lower surface side of the tool holder 10, and a corner of the bent portion has a tool holder 10 to be described later.
The sliding surface 20 in contact with the inclined surface 19 of the clamp piece 1
4 is formed over the entire length in the width direction. As shown in more detail in FIG. 4, the sliding surface 20 gradually curves downward at a constant curvature R ₃ from one end to the other end in the longitudinal direction of the clamp piece 14 similarly to the above-described pressing surface 17. It is formed in a convex curved surface shape extending. In addition, a restraining surface 22 is formed below the sliding surface 20 to abut against the locking wall 21 of the tool holder 10 and to prevent the clamp piece 14 from rotating around the clamp bolt 15. Note that the restraining surface 22 is formed on a plane orthogonal to the longitudinal direction of the clamp piece 14.

As shown in FIGS. 1 and 2, a screw hole 23 for screwing with the clamp bolt 15 is formed in a portion of the tool holder 10 behind the tip mounting seat 11. The screw hole 23 extends in a direction orthogonal to the bottom surface 11a of the chip mounting seat 11, and a counterbore portion 23a is formed coaxially on the upper end side. A coil spring 24 having a diameter slightly smaller than that of the counterbore 23a is disposed between the counterbore 23a and the tapered portion 15a of the clamp piece 14, whereby the clamp piece 14 always faces upward. Have been energized.

Further, on the rear side of the screw hole 23 of the tool holder 10, there is formed an inclined surface 19 which is gradually inclined toward the lower surface side of the tool holder 10 as the distance from the tip mounting seat 11 to the rear increases. The inclined surface 19 has a length substantially equal to the width of the clamp piece 14, and its inclined angle θ with respect to a direction perpendicular to the chip mounting seat bottom surface 11a is constant over the entire surface.

Further, a locking wall 21 is formed below the inclined surface 19 so as to be parallel to the axis O1 of the screw hole 23. The axis O of the counterbore 23a of the locking wall 21
The distance S from 1 is set slightly larger than the distance m from the restraining surface 22 of the clamp piece 14 to the axis O2 of the tapered portion 15a, so that the locking wall 21 and the restraining surface 22 are brought into close contact with each other. In this state, the axis O2 of the tapered portion 15a of the clamp piece 14 is aligned with the counterbore 25 of the tool holder 10.
a minute amount L1 toward the rear side of the tool holder 10 with respect to the axis O1 of FIG.
(= S−m) (see FIG. 2).

Next, the operation of the tip clamp mechanism configured as described above will be described. In order to clamp the chip 7 by the chip clamping mechanism of the present embodiment, first, as shown in FIG.
4 and the counterbore 23 of the tool holder 10
The clamp bolt 16 is gradually tightened in the state where the clamp piece 14 is fitted to the position a, and the clamp piece 14 is moved downward until the sliding surface 20 comes into contact with the inclined surface 19 of the tool holder 10.

At this time, the tapered portion 15a of the clamp piece 14
Is slightly eccentric behind the counterbore portion 23a of the tool holder 10, so that the coil spring 24 is largely bent toward the rear end side of the tool holder 10 toward the upper end, and is generated according to the amount of bending. The clamp piece 14 is urged toward the tip end of the tip mounting seat 11 by the restoring force. Therefore, until the inclined surface 19 and the sliding surface 20 come into contact with each other,
A restraining surface 22 is in close contact at all times of the engaging wall 21 and the clamp piece 14 of the tool holder 10, thereby rotating around the axis O ₁ of the clamp bolt 15 of the clamping piece 14 is prevented, further clamping piece 14 engaging It is guided by the wall 21 and descends straight in a direction perpendicular to the bottom surface 11a of the chip mounting seat 11. For this reason, as the clamp piece 14 descends, the projection 18 does not ride on the upper surface of the
a is securely fitted.

After the sliding surface 20 of the clamp piece 14 and the inclined surface 19 of the tool holder 10 come into close contact with each other, the clamp bolt 16 is further tightened. As a result, the sliding surface 20 moves along the inclined surface 19, so that the clamp piece 14 moves not only below but also behind the tip mounting seat 11. As a result, the pressing surface 17 of the clamp piece 14 comes into contact with the upper surface of the chip 7 to press the chip 7 against the bottom surface 11a of the chip mounting seat 11, and at the same time, the projection 18 of the clamp piece 14 is inserted into the chip mounting hole 7a. circumferential surface engaged with the chip 7 is Ru pulled rearward of the chip mounting seat 11. At this time,
The engagement surface between the projection 18 and the mounting hole 7a, that is,
The rear end of the outer peripheral surface and the rear end of the inner peripheral surface of the mounting hole 7a are
Chip mounting seat for bottom surface 11a of chip mounting seat 11
11 The angle of the tip side is 90 degrees or less.
Thus, detachment of the projection 18 from the mounting hole 7a is prevented.
As a result, the chip 7 is pressed against the side surface 11b of the chip mounting seat 11, and the chip 7 is firmly fixed.

Here, in the tip clamping mechanism of the present embodiment, the pressing surface 17 and the sliding surface 20 of the clamp piece 14 are both formed into a convex curved surface, and the range in which the pressing surface 17 is formed is the mounting range of the chip 7. As shown in FIGS. 6 and 7, the clamp piece 14 is inclined with respect to the upper surface of the tool holder 10 so that the sliding surface 20 is formed at the lower end of the inclined surface 19. even if the side and upper side such as to contact the chip 7 and the pressing surface 17 abuts always in diagonal direction central portion near the tip 7, the clamping piece 14 the tip of the
Contact is prevented. As a result, as shown by hatching in FIG. 8, a substantially uniform longitudinal clamping force acts on the chip 7 over the entire surface, and the chip 7 is stably clamped. Therefore, according to the tip clamping mechanism of the present embodiment, it is possible to prevent the rear end of the tip 7 from being lifted when the tip 7 is used, thereby avoiding deterioration of machining accuracy and loss of the cutting edge.

Further, according to the tip clamping mechanism of the present embodiment, the tip 18a of the projection 18 provided on the clamp piece 14 is also formed in a convex curved shape, so that the projection 18 as shown in FIG. Even in the case where the axis of the mounting hole 7a of the chip 7 is relatively displaced from the axis of the chip 7, the projection 18 can be easily inserted into the mounting hole 7a. Accordingly, the difference between the outer diameter d of the projection 18 and the inner diameter D of the mounting hole 7a can be set smaller than in the past, and therefore, a chip clamping mechanism capable of increasing clamping rigidity and sufficiently withstanding heavy cutting is provided. it can. In this embodiment, in particular, the outer peripheral surface of the projection 18 is formed in a cylindrical shape over the entire circumference, but the present invention is not limited to this, and the projection 18 comes into contact with the inner peripheral surface of the mounting hole 7a. If only the side is formed in a cylindrical surface, the remaining portion may be flat.

Further, in the present embodiment, the range in which the pressing surface 17 is formed is limited to the vicinity of the protruding portion 18 so as to press the diagonally center portion of the chip 7, so that the tip side of the chip 7 is positively moved. The distance from the tip of the clamp piece 14 to the center point P ₀ of the projection 18 can be greatly reduced as compared with the conventional tip clamp mechanism that has been pressed. For this reason, the distance e (see FIG. 3) from the cutting edge 8 to the tip of the clamp piece 14 in a state where the chip 7 is clamped is set to be larger than that of the above-described conventional chip clamping mechanism, and chips generated from the work material are set. Damage and premature wear of the clamp piece 14 due to the rubbing of the clamp piece 14 can be avoided.

In order to release the clamp of the tip 7 in the tip clamping mechanism of the present embodiment, the clamp bolt 16 may be gradually loosened in the reverse order of the above procedure.
As shown in FIG. 1, the amount of eccentricity L between the tapered portion 15a of the clamp piece 14 and the counterbore portion 23a of the tool holder 10 increases due to the movement of the clamp piece 14 to the rear side of the tip mounting seat 11 during tip clamping. Therefore, in the tip clamp state, the bending of the coil spring 24 increases, and the force for urging the clamp piece 14 toward the tip end of the tip mounting seat 11 also increases. Accordingly, even in the process of loosening the clamp bolt 16, the sliding surface 20 of the clamp piece 14 moves along the inclined surface 19 of the tool holder 10, and after they are separated, the locking wall 21 and the restraining surface 22 come into close contact. For this reason, even when the clamp is released, the rotation of the clamp piece 14 is prevented, and the clamp piece 14 rises in a fixed posture. As a result, the operability is greatly improved in any of the above-described clamp work and clamp release work. .

In the above-described embodiment, in order to improve the workability particularly during the clamping operation, the clamp surface 14 is
Is formed and is brought into contact with the locking wall 21 of the tool holder 10. However, the present invention does not require this, and may be omitted if unnecessary. Further, the shape of the chip 7 is not limited to a rhombic flat plate shape, and can be appropriately changed, such as a triangular flat plate shape.

[0026]

As has been described above devised] According to this invention, the inclination to form a pressing surface of the clamping piece in a convex curved shape, because that adjacent forming the pressing surface in the vicinity of the protrusion, with respect to the tool holder clamp piece Regardless of the degree of contact, the pressing surface and the chip always contact near the mounting hole formed almost in the center of the chip, preventing the tip of the clamp piece from abutting.
You. As a result, the chip can be pressed down with a substantially uniform clamping force over the entire surface, and deterioration of processing accuracy due to lifting of the chip rear end side and loss of the cutting edge can be prevented. Also, insert the tip at the rear end of the tip mounting
When pulling, make sure that the engaging surfaces of both the protrusion and the mounting hole are small.
At least a part of the tip
The angle on the tip side of the mounting seat is 90 degrees or less.
Therefore, detachment of the projection from the mounting hole is prevented. this
The chip is pressed against the rear end of the chip mounting seat
The tip is firmly fixed. Furthermore, the pressing surface is
Because it is formed in the vicinity, positively touch the tip end of the chip
The distance from the cutting edge to the tip of the clamp piece when the tip is clamped can be set larger than in the past , compared to the conventional tip clamp mechanism that was pressing. Damage and premature wear can be avoided.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a tip clamp mechanism according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a state in which the tip clamp is released in the tip clamp mechanism of FIG. 1;

FIG. 3 is a view as seen from the direction of arrow III in FIG. 1;

FIG. 4 is a cross-sectional view of the clamp piece according to the embodiment of the present invention, taken along a longitudinal direction.

FIG. 5 is a view from arrow V in FIG. 4;

FIG. 6 is a cross-sectional view showing a state in which the tip is clamped in a state where the clamp piece is inclined in the tip clamp mechanism shown in FIG. 1;

FIG. 7 is a cross-sectional view showing a state where the tip is clamped in a state where the clamp piece is inclined to the opposite side to the case shown in FIG. 6;

FIG. 8 is a diagram showing a distribution of a longitudinal clamping force applied to a chip.

FIG. 9 is a diagram showing a state in which a protrusion of a clamp piece is inserted into a mounting hole of a chip.

FIG. 10 is a sectional view showing a conventional tip clamp mechanism.

FIG. 11 is a diagram showing a distribution of a longitudinal clamping force in a conventional tip clamping mechanism.

FIG. 12 is a diagram showing a state in which a tip clamped by a conventional tip clamping mechanism is used for cutting a work material.

FIG. 13 is a view showing interference between a clamp piece and chips.

[Explanation of symbols]

 Reference Signs List 7 Indexable insert 7a Mounting hole 10 Tool holder 11 Chip mounting seat 11a Bottom surface of chip mounting seat 11b Side surface of chip mounting seat 14 Clamp piece 17 Pressing surface 18 Protrusion 18a Tip of projection 19 Slope 20 Sliding surface

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-58-59705 (JP, A) JP-A-51-19382 (JP, U) JP-B-49-6262 (JP, B1) JP-B-52- 46745 (JP, B2) Jikken Sho 51-22626 (JP, Y2)

Claims (1)

(57) [Scope of request for utility model registration] 1. A tip mounting seat is formed on an upper surface side of a tip end portion of a tool holder, a clamp piece is disposed above the tip mounting seat, and a throw placed on the tip mounting seat on a lower face side of the clamp piece. A pressing surface that comes into contact with the away tip and a projection that fits into the mounting hole formed in the throw away tip are formed, and the projection of the clamp piece is fitted into the mounting hole of the throw away tip. By pressing the clamp piece against the lower surface of the tool holder in the state, the tip away mechanism is pressed toward the bottom surface of the chip mounting seat and is pulled toward the rear end side of the chip mounting seat to be fixed. On the upper surface of the tool holder, the inclination gradually inclines toward the lower surface of the tool holder as the distance from the tip mounting seat to the rear end of the tool holder increases. While forming the surface, the lower surface side of the clamping piece forms the inclined surface abutting the sliding surface, the pressing surface of the clamping piece, apart from those projecting from the protrusion
A convex curved surface is formed adjacent to the vicinity of the raised portion, and at least one of the engagement surfaces of both the projection and the mounting hole is formed.
The tip with respect to the bottom surface of the tip mounting seat.
A tip clamp mechanism characterized in that the angle of the mounting seat tip side is 90 degrees or less .