JPH081413A - Cutting head for machine tool - Google Patents

Abstract

PURPOSE:To provide a cutting head for a machine tool capable of rapid and correct recessing, facing, etc., without applying the overload to a motor with simple operation by allowing a turning tool to be automatically advanced and retracted in the direction orthogonal to a spindle only by the rotation of the spindle in the same direction. CONSTITUTION:When a supporting cylinder 10 is mounted on a frame of a machine tool, and a rotary shaft 11 is connected to a spindle to be rotated, a tool holder 22 and a turning tool 25 fixed to the lower end thereof are rotated together with the rotary shaft 11. An off-centered cam 19 interlocked with the rotary shaft 11 through a reduction gear mechanism 20 is gradually and relatively rotated to the rotary shaft 11, and the tool holder 22 having a guide piece 23 to hold the off-centered cam 19 from each side and the turning tool 25 are gradually shifted to the outwardly side orthogonal to the rotary shaft 11 to execute the recessing, facing, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used by being mounted on a spindle of a drilling machine, a machining center or the like, and while rotating a bite, it is gradually moved in a direction orthogonal to the axis of the spindle to perform reprocessing or facing. The present invention relates to a cutting head for machine tools.

[0002]

2. Description of the Related Art In order to cut an annular groove on an inner surface of a circular hole of a work, that is, to perform re-sizing, usually, while holding the work on a chuck of a lathe and rotating the work, a cutting tool inserted into the circular hole is used. It is moved in the diameter direction.

In this case, however, the work is attached to and detached from the chuck and the annular groove is cut manually, which is troublesome when there are many works and defective products often occur. Such a device is provided.

In FIG. 7, (1) is a main body which is fixedly mounted on a fixed part such as a drilling machine and is fixed to the rotary part at a lower part thereof.
(3) is connected to the spindle (2) and rotated.
The engaging portion (4a) on the upper surface of the bite holder (4) is slidably fitted in a dovetail-shaped engaging groove (not shown) cut on the lower surface of the rotating portion (3) and suspended. A bite (6) is attached to the lower end of an attachment rod (5) which is supported and hangs down from the bite holder (4).

When the spindle (2) rotates forward, the bite holder (4) gradually advances to the outside, which is the right side of FIG. 7,
When it is rotated in the reverse direction, it retreats inward, which is the left side in FIG. 7.

In the above-mentioned apparatus, the mounting rod (5) having the bite (6) mounted therein is inserted into the circular hole (8) of the fixed bottomed cylindrical work (7), and the spindle (2) is inserted. When it is rotated forward, the bite (6) rotates with the spindle (2) and advances outward together with the bite holder (4) to cut an annular groove (9) on the inner surface of the circular hole (8), When the groove (9) is cut to a predetermined depth, the stopper pin provided inside contacts a stopper (none of which is shown) and the clutch is disengaged. Annular groove
When (9) is cut to a predetermined depth, the spindle (2) may be rotated in the reverse direction so that the bite holder (4) and the bite (6) move backward. Attach the bite (6) to the rod.
When it is attached to the lower end of (5) so as to face directly downward or obliquely downward, so-called facing processing can be performed, in which a shallow step hole or the like is formed at the opening edge of the circular hole (8) of the work (7).

[0007]

In the device schematically shown in FIG. 7, when the bite (7) cuts the annular groove (10) to a predetermined depth, the tool holder (4) is stopped by a stopping means such as a stopper. It is necessary to stop the forward movement and rotate it in the reverse direction, the operation is troublesome and time consuming, the motor is overloaded when the stopper comes into contact, or the depth of the annular groove (9) is accurately set. Is difficult. That is, there is a problem that it is difficult to precisely position the forward end of the cutting tool.

In view of the above-mentioned problems of the prior art, the present invention allows the bite to automatically advance and retract in the direction orthogonal to the spindle only by rotating the spindle in the same direction. An object of the present invention is to provide a cutting tool head for machine tools that is easy to operate, does not overload the motor, and can quickly and accurately perform recessing and facing processing.

[0009]

According to the present invention, the above problems can be solved as follows.

(1) A support shaft mounted on a frame of a machine tool is provided with a vertical rotary shaft connected to a spindle of the machine tool, and a guide groove diametrically oriented at the lower end of the rotary shaft. A horizontal engaging portion provided at the upper end of the bite holder, which is capable of fixing the bite at the lower end, is slidably fitted in the guide groove. An eccentric cam externally fitted to the lower end of the rotating shaft is rotatably sandwiched from both sides by a pair of guide pieces that stand upright from both ends, so that the eccentric cam and the rotating shaft have an input rotation speed and an output rotation speed. They are linked to each other by a reduction gear mechanism that is slightly different.

(2) In the above item (1), the reduction gear mechanism is externally fitted to the rotary shaft, one of which is fixed to the rotary shaft and the other of which is fixed to the eccentric cam so as to have a small number of teeth. And at least two spur gears different from
In addition, at least one transmission gear having two teeth having the same or similar number of teeth meshing with the two spur gears.

(3) In the above item (2), an intermediate spur gear is provided between the two spur gears, and the intermediate spur gear and the other spur gears are linked by different linkage gears.

(4) In the above item (1), the reduction gear mechanism is formed in the support cylinder so as to be eccentric with the external gear that is fitted onto the rotation shaft and is prevented from rotating. It has an internal gear that is rotatably fitted in the annular groove, meshes with the external gear with a slightly different number of teeth from the external gear, and is linked to the eccentric cam so as not to rotate relative to it. .

(5) In any one of the above items (1) to (4), the guide groove is a dovetail groove, and the engaging portion of the bite holder slidably fitted therein is a dovetail shape.

(6) In any one of the above items (1) to (5), a friction joint is provided in the transmission path from the rotary shaft to the eccentric cam via the reduction gear mechanism.

(7) In the above item (6), the friction joint is
Spring catch.

[0017]

When the support cylinder is mounted on the frame of the machine tool and the rotary shaft is connected to the spindle for rotation, the rotary tool and the bite fixed to the lower end are rotated together with the rotary shaft, and the speed is reduced. The eccentric cam linked to the rotary shaft via the gear mechanism gradually rotates relative to the rotary shaft, and accordingly, the bite holder and the bite having the guide pieces that sandwich the eccentric cam from both sides are It is gradually moved toward the outer side orthogonal to, and reprocessing, facing, etc. are performed.

When the dead center of the eccentric cam passes the guide piece, the moving direction of the bite holder reverses and gradually moves inward, so it is not necessary to bring the bite holder into contact with the stopper to stop it.

[0019]

1 to 3 show an embodiment of the present invention as claimed in claims 1 to 3 and are mounted on a frame (not shown) such as a drilling machine or a machining center so as not to rotate. A rotating shaft (11) oriented in the up-down direction is inserted into the support cylinder (10) and is pivotally supported by a bearing (12). The upper end of the rotary shaft (11) is connected to a spindle (not shown) such as a drilling machine.

Near the lower end of the rotary shaft (11), the drive spur gear (1
3) is externally fitted to prevent rotation, and the drive spur gear is directly below it.
An intermediate spur gear (14) slightly larger in diameter than the (13) is rotatably fitted outside, and immediately below it, a driven spur gear (15) having a diameter intermediate between both spur gears (13) and (14). Is rotatably fitted on the outside.

The drive spur gear (13) and the intermediate spur gear (14), and the intermediate spur gear (14) and the driven spur gear (15) are respectively support cylinders.
It is linked by a first link gear (17) and a second link gear (18) pivotally provided on a support ring (16) fixed to the lower surface of (10). Both linkage gears (17) and (18) are small diameter 2 with slightly different outer diameter.
It has upper and lower teeth (17a), (17b), (18a), and (18b) that are coaxial with each other.

Thus, the drive spur gear (13) and the intermediate spur gear (1
4), the driven spur gear (15) and the linkage gears (17) (18) form a reduction gear mechanism (20) in which the input rotation speed and the output rotation speed are slightly different from each other. The number of these teeth can be determined as follows, for example.

Drive spur gear (13) -112, teeth (17a) -40, teeth (1
7b) -38, intermediate spur gear (14) -116 (the number of teeth may be any number), teeth (18a) -34, teeth (18b) -36, driven spur gear (15) -11
Four.

Therefore, together with the rotary shaft (11), the drive spur gear
When (13) rotates, the driven spur gear (15) rotates together with the drive spur gear (13) at a slightly different rotation speed, and the driven spur gear (15)
Rotates at a slow speed relative to the rotation axis (11). With the number of teeth as above, while the rotating shaft (11) makes 200 rotations,
The driven gear (15) rotates 201.176.

On the lower surface of the driven spur gear (15), an eccentric cam (19) rotatably fitted on the rotating shaft (11) is integrally connected. A guide groove (21) which is a dovetail groove facing the diametrical surface of the rotating shaft (11) is cut on the lower surface of the rotating shaft (11).

In the guide groove (21), a horizontally oriented dovetail-shaped engaging portion (22a) formed on the upper surface of the bite holder (22) is fitted so as to be slidable sideways. Is suspended. A pair of upwardly projecting guide pieces (23) are fixed to both ends of the engaging portion (22a) of the bite holder (22), and an eccentric cam (9) is provided between the upper inner surfaces of both guide pieces (23). Is sandwiched as rotatable.

Tool holder rod vertically mounted on the tool holder (22)
At the lower end of (24), a bite (25) facing sideways is attached.

In the above-mentioned device of the present invention, the rotating shaft (11)
With the initial position of the bite holder (22) to the predetermined position, the bite (25) is inserted into the circular hole (27) of the cylindrical work (26) with a bottom, and then the rotary shaft (11) is rotated. If the byte (2
5) rotates with the rotating shaft (11) to start cutting.

As the rotating shaft (11) rotates, the eccentric cam (19) is gradually rotated by the reduction gear mechanism (20) relative to the rotating shaft (11). ) By a differential rotation, the bite holder (22) having a pair of guide pieces (23) sandwiching the eccentric cam (19) moves along the guide groove (21) along with the bite (2
The annular groove (28) is gradually cut deeper by gradually advancing toward the protruding outer side of (5).

The portion corresponding to the top dead center of the eccentric cam (19) is
When passing through the guide piece (23) on the right side of FIG. 1, the bite holder (22) is most advanced and the annular groove (28) is cut to a predetermined depth. After that, when the eccentric cam (19) continues to rotate further differentially, the bite (25), together with the bite holder (22), moves to the position shown in FIG.
Begin the retreat to the left, i.e. inward, of the annular groove (28)
Escape more.

In the embodiment described above, the drive spur gear (13)
The intermediate spur gear (14) is provided between the driven spur gear (15) and
When the drive spur gear (13) and the driven spur gear (15) can have sufficiently large diameters, the intermediate spur gear (14) and the second link gear (18) may be omitted.

4 and 5 show an embodiment of the invention as claimed in claims 4 and 5. In this embodiment, the same members as those in FIGS. 1 to 3 are denoted by the same reference numerals and only shown, and detailed description thereof is omitted (the same applies to the embodiment shown in FIG. 6 described later. And). In the embodiment of FIGS. 4 and 5, the reduction gear mechanism (30) has a structure similar to a so-called harmonic drive mechanism.

That is, the reduction gear mechanism (30) has a rotary shaft (1
The external gear (31) that is externally fitted to the (1) and is not rotated, and is rotatably fitted into the annular groove (32) formed in the support cylinder (10) so as to be eccentric with the rotating shaft (11). Combined with external gear
It has an internal gear (33) which meshes with the external gear (31) with a number of teeth slightly different from that of (31), and which is linked to the eccentric cam (34) so as not to rotate relative to it.

At the lower end of the internal gear (33), a plurality of projections (35) facing the centripetal direction are provided at equal intervals in the circumferential direction, and each projection (35) is a shaft of the eccentric cam (34). By engaging with the radial groove (36) formed at the upper end of the portion (34a), the internal gear (33) is rotated relative to the shaft portion (34a) of the eccentric cam (34).
It is possible to move in the direction orthogonal to (11), but it is linked so that relative rotation is impossible.

Even with the configuration shown in FIGS. 4 and 5,
The reduction gear mechanism (30) can transmit the rotational force of the rotating shaft (11) to the eccentric cam with a reduction ratio extremely close to 1, and achieve the same action and effect as those in FIGS. 1 to 3. You can

FIG. 6 shows an embodiment of the invention according to claims 6 and 7. In the embodiment shown in FIG. 6, the rotary shaft (1
A spring catch type friction joint (40) is provided between 1) and the drive spur gear (13).

This friction joint (40) is provided with a cross-shaped hole (41) at a portion of the rotary shaft (11) which is at the same height as the drive spur gear (13), and the outer end of this hole (41). Steel balls (42) arranged on the inner and inner ends
Compress the compression springs (43) between the (42) respectively, and between the four steel balls (42) at the center, at the upper end of the adjusting screw (44) screwed from the center of the lower end of the rotating shaft (11). By moving the formed conical portion (44a) forward and backward, the outward biasing force of the outer steel ball (42) by the compression spring (43) can be adjusted, and the outer steel ball (42) is adjusted.
Is urged by the compression spring (43) and engages with the longitudinal grooves (45) formed at equal intervals in the circumferential direction on the inner surface of the drive spur gear (13), whereby the rotary shaft (11) When a torque exceeding the limit is applied between the drive spur gear (13) and the drive spur gear (13), the rotating shaft (11) and the drive spur gear (13) rotate relative to each other to prevent damage to the transmission parts. Has become.

Incidentally, such a friction joint (40) is
It may be provided at any position on the transmission path from (11) to the eccentric cam (19) through the reduction gear mechanism (20).

By providing such a friction joint (40), safety can be improved and
The tool holder (2) is combined with an appropriate sensor (not shown) that detects one reciprocation of the tool holder (22) along the guide groove (21).
If 2) does not make one reciprocation within the preset time, it is more effective to stop the spindle rotation by assuming that some abnormality such as slipping of the friction joint (40) has occurred. is there.

[0040]

According to the present invention, the following effects can be obtained. (a) By simply continuing to rotate the rotary shaft in the same direction, the bite will slowly and continuously reciprocate in the direction orthogonal to the rotary shaft due to the action of the eccentric cam, and the range of movement will be predetermined by the eccentricity of the eccentric cam. Therefore, when performing recessing or the like, it is possible to accurately determine the depth and the like of the annular groove to be cut and perform high-precision processing.

(B) If the workpieces are exchanged while the cutting tool is moving backward, a large number of workpieces can be continuously and quickly processed without stopping the rotation of the rotary shaft. , Can increase productivity.

(C) Since it is not necessary to stop the outward movement of the cutting tool with a stopper or the like as in the conventional case, the motor is not overloaded, a clutch is provided, and the motor is frequently turned on. , There is no need to turn it off.

(D) When the reduction gear mechanism according to the second aspect is used, the entire head can be compacted and downsized, and the reduction ratio can be remarkably brought close to 1, so that the bite with respect to the rotation speed of the rotary shaft can be reduced. Precise machining can be performed by lowering the feeding speed. In particular, claim 3
By doing so, the speed reduction ratio can be made even closer to 1.

(E) By using a reduction gear mechanism similar to the harmonic drive mechanism according to the fourth aspect, it is possible to further downsize the entire head, reduce the number of gears used, and simplify the structure. You can

(F) When the guide groove is a dovetail groove and the engaging portion of the bite holder slidably fitted into the guide groove is dovetailed, the bite holder is provided at the lower end of the rotary shaft. It can be easily suspended, and there is no need to provide additional means to prevent the bite holder from falling.

(G) If a friction joint is provided in the transmission path from the rotary shaft to the eccentric cam through the reduction gear mechanism, the limit can be provided between the rotary shaft and the eccentric cam. When the above torque is applied, slippage occurs in the friction joint and damage to the transmission component can be prevented, which is safe.

(H) If the friction joint is a spring catch as in claim 7, the structure can be simplified.

[Brief description of drawings]

FIG. 1 is a central longitudinal front view of an embodiment of the present invention according to claims 1 to 3;

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is a sectional view taken along line BB of FIG.

FIG. 4 is a central longitudinal front view of an embodiment of the present invention according to claims 4 and 5.

5 is a cross-sectional view taken along line CC of FIG.

FIG. 6 is a central longitudinal front view of an embodiment of the present invention according to claims 5 to 7.

FIG. 7 is a front view of a conventional device with some cutaways and a part omitted.

[Explanation of symbols]

 (1) Support tube (2) Spindle (3) Guide plate (4) Tool holder (4a) Fitting part (5) Tool mounting rod (6) Tool (7) Work piece (8) Circular hole (9) Annular groove ( 10) Support cylinder (11) Rotating shaft (12) Bearing (13) Drive spur gear (14) Intermediate spur gear (15) Driven spur gear (16) Support ring (17) First linkage gear (18) Second linkage gear (19) Eccentric cam (20) Reduction gear mechanism (21) Guide groove (22) Tool holder (22a) Engagement part (23) Guide piece (24) Tool mounting rod (25) Tool (26) Work (27) Circle Hole (28) Annular groove (30) Reduction gear mechanism (31) External gear (32) Annular groove (33) Internal gear (34) Eccentric cam (34a) Shaft (35) Protrusion (36) Groove (40) Friction joint (41) Hole (42) Steel ball (43) Compression spring (44) Adjustment screw (44a) Cone (45) Groove

Claims (7)

[Claims] 1. A support cylinder mounted on a frame of a machine tool is provided with a rotary shaft connected to a spindle of the machine tool, the rotary shaft facing up and down, and a guide groove facing the diametrical direction at the lower end of the rotary shaft. A horizontal engaging portion provided on the upper end of a cutting tool holder, which is cut and fixed to the lower end of the cutting tool, is slidably fitted to both ends of the engaging portion of the cutting tool holder. By the pair of guide pieces that stand upright, the eccentric cam fitted on the lower end of the rotary shaft is rotatably sandwiched from both sides, and the eccentric cam and the rotary shaft have a small input rotation speed and a small output rotation speed. A machining head for machine tools, characterized in that they are linked to each other by different reduction gear mechanisms. 2. A reduction gear mechanism is fitted onto a rotary shaft,
At least two spur gears, one of which is fixed to the rotating shaft and the other of which is prevented from rotating by the eccentric cam, and has a slightly different number of teeth, and the two spur gears that are pivotally supported by the support cylinder. The cutting head for a machine tool according to claim 1, further comprising: at least one linking gear having two teeth having the same or similar number of meshing teeth. 3. An intermediate spur gear is provided between two spur gears, and the intermediate spur gear and the other spur gears are linked by separate linking gears, respectively. Cutting head for machine tools. 4. A reduction gear mechanism is rotatably fitted in an externally toothed gear that is fitted onto a rotating shaft and is prevented from rotating, and an annular groove formed in a support cylinder so as to be eccentric to the rotating shaft. The machine tool according to claim 1, further comprising: an internal gear that meshes with the external gear with a slightly different number of teeth from the external gear and that is linked to the eccentric cam so as to be relatively non-rotatable. Cutting head. 5. The cutting head for a machine tool according to claim 1, wherein the guide groove is a dovetail groove, and the engaging portion of a bite holder slidably fitted into the guide groove is dovetailed. 6. The cutting head for a machine tool according to claim 1, wherein a friction joint is provided in the transmission path from the rotary shaft to the eccentric cam via the reduction gear mechanism. 7. The cutting head for machine tools according to claim 6, wherein the friction joint is a spring catch.