JPH0244644B2 - KOGUNOJUMYOKENSHUTSUKIKOOSONAETAKOGUHETSUDO - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a tool head equipped with a tool life detection mechanism, and more specifically, it has become possible to prevent breakage of cutting tools. Regarding tool heads.

Conventional technology When a cutting tool such as a drill or an end mill suffers wear, it not only impairs the machining accuracy of the workpiece, but also causes the cutting tool to break and shorten its lifespan. It is important to detect the progress of cutting tools and detect the lifespan of cutting tools.

The first conventional technology for this type of life detection is to detect the vibration of cutting tools during machining using an acceleration sensor attached to the frame of machine tools such as drilling machines, milling machines, and machining centers, and detect the progress of wear based on the detection results. I now have a way to understand the situation.

Further, as a second conventional technique, there is a method of detecting the load on an electric motor that drives the main shaft of a machine tool connected to a cutting tool, and grasping the progress of wear based on the detection result.

Furthermore, as a third conventional technique, there is a method in which the life time of a cutting tool is set in advance through experiments, actual results, etc., and prediction is made based on this life time.

Problems to be Solved by the Invention However, when using detection forms such as the above-mentioned first and second conventional examples, there is a drawback that the device configuration becomes complicated and large-scale.

Furthermore, the third conventional technique has the disadvantage that it is not possible to accurately grasp the progress of wear of the cutting tool.

The present invention has been made in order to solve the problems of the prior art, and provides a tool head equipped with a tool life detection mechanism that can itself accurately detect the tool life. With the goal.

Means for Solving the Problems A tool head equipped with a tool life detection mechanism according to the present invention includes a tool head main body having a cylindrical portion on the distal end side of a shaft portion connected to the main shaft of a machine tool, and the cylindrical portion. one or more engagement grooves formed in the circumferential direction at the tip of the inner circumferential surface, and the same number of engagement grooves as the engagement grooves are formed in the inner circumferential surface, and the tip side is a part of the engagement groove. a retraction groove communicating with the engaging groove, a receiving wall formed at the proximal end of the engagement groove, and a proximal end inserted into the cylindrical part,
a tool drive shaft that holds a cutting tool at its tip; one or more engaging convex portions that are formed protrudingly on the outer circumferential surface of the intermediate portion of the tool drive shaft and that engage with the receiving wall; and the tool drive shaft. One end is connected to the shaft, and the retraction spring is elastically biased toward the proximal end, and the proximal end has a locking claw that engages with the engagement groove. an engagement ring attached to the distal end of the cylindrical part so as to press the engagement protrusion against the receiving wall with a pressing surface formed in a single-sided flow; and an engagement ring that presses the engagement ring toward the proximal end. and a spring member for biasing the cutting tool, the engagement convex portion is disengaged from the receiving wall due to fluctuations in the torque acting on the cutting tool, and the tool drive shaft is guided by the retraction groove to the proximal end side. It's starting to move in and out.

Function When the cutting tool's cutting edge becomes worn due to long-term use, etc., and the cutting resistance increases, the torque of the cutting tool, that is, the tool drive shaft that holds it, increases. The engagement protrusion attached to the tool head body rotates (slips) relative to the engagement ring which rotates in conjunction with the tool head body. Then, as shown by the imaginary line in FIG.
The engaging ring body 4 is pressed toward the distal end side against the biasing force of , detaches from the receiving wall 15, and jumps into the retraction groove 14. After that, the engagement pin 20,
That is, since the tool drive shaft is always urged toward the proximal end by the retraction spring, the tool drive shaft, that is, the cutting tool, is guided by the retraction groove 14 and retracts toward the base end.

Example Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a longitudinal sectional view of a tool head equipped with a tool life detection mechanism according to the present invention, FIG. 2 is an exploded perspective view of main parts, and FIG. 3 is a sectional view taken along line AA in FIG. 1. FIG. 4 is a developed view for explaining the detachment operation of the engagement pin from the receiving wall.

A cylindrical tube portion 11 is provided on the distal end side of a tool head main body 1 formed by connecting a taper shank 10 provided on the proximal end side to the main shaft of a machine tool (not shown). Engagement grooves 13, 13 are provided at opposing positions on the inner circumferential surface of the distal end of the cylindrical portion 11, and are recessed with an appropriate width in the circumferential direction. At the proximal end sides of the engagement grooves 13, 13, recessed lead-in grooves 14, 14 whose width is narrower than the engagement grooves 13, 13 are recessed. That is, as shown in FIG. 4, the tip of the retraction groove 14 is communicated with a part of the engagement groove 13 in the circumferential direction, and the receiving wall 15 is formed in the remaining part of the engagement groove 13. It's summery.

A proximal end of a hollow tool drive shaft 2 having a drill 3 held at its tip is inserted into the cylindrical portion 11 and connected thereto. The tool drive shaft 2 is attached to be rotatable in conjunction with the cylindrical portion 11 and to be slidable relative thereto in the axial direction. That is, an engagement pin 20 is driven into the middle part of the tool drive shaft 2 in the radial direction thereof with both ends protruding, and under normal conditions, this protrusion engages the locking claws 40, 40 of the engagement ring body 4 described below. This causes the tool drive shaft 2 to rotate relative to the cylindrical portion 11, that is, the drill 3 to rotate relative to the tool head body 1.

Note that the means for interlocking the tool drive shaft 2 and the tool head body 1 is not limited to the above-mentioned engagement pin 20, and the means for interlocking the tool drive shaft 2 with the engagement convex portion that is engaged with the receiving wall 15 is Since it is only necessary that the ball be provided on the outer circumferential surface, for example, the ball may be attached to the outer circumferential surface of the tool drive shaft 2,
A short pin may be formed to protrude. Moreover, the number of these is not limited to two, and may be one, or three or more may be provided. Of course, in this case, the engagement groove 13, the retraction groove 14, and the locking pawl 40 described below
The number of engagement protrusions is selected to be the same as the number of engagement protrusions. Furthermore, although it is desirable that the tool drive shaft 2 be formed hollow in order to reduce weight, it may be solid. In this case, the tip of the retraction spring 21 may be locked and connected to the base end of the tool drive shaft.

On the other hand, when the tool drive shaft 2 rotates relative to the engagement ring body 4 as shown in FIG.
0 detaches from the receiving wall 15, jumps into the retraction groove 14, and then slides toward the proximal end. This sliding movement is performed by a retraction spring 21 made of a coil spring that always urges the engagement pin 20 toward the proximal end. That is, the retraction spring 21 has its distal end latched and connected to the center of the engagement pin 20, and its base end latched and connected to the center of the latching pin 22 driven into the taper shank 10.

At the tip of the cylindrical portion 11, as described above, there is an engagement ring 4 that presses the engagement pin 20 against the receiving wall 15 to enable interlocking rotation of the tool drive shaft 2 and the tool head body 1.
is inset. That is, locking pawls 40, 40 of an appropriate width are formed protruding from the proximal end side of the engaging ring body 4, and engage with the engaging grooves 13, 13, respectively.
A pressing surface 4 for pressing the protruding portions at both ends of the engagement pin 20 against the receiving walls 15, 15 is provided on a part of the circumferential direction of the engagement pin 20.
1,41 are provided. As shown in FIGS. 2 and 4, this pressing surface 41 is an inclined surface that has a one-sided flow in the circumferential direction, and the direction of the inclination is toward the tip end side.

A disc spring 5 is provided on the distal end side of the engagement ring body 4 to always press the engagement ring body 4 toward the proximal end side with a predetermined spring pressure. The disc spring 5 is used to set the torque of the drill 3 in conjunction with a torque setting nut member 6 screwed onto the outer peripheral surface of the tip of the cylindrical portion 11.
That is, the torque setting nut member 6 has a cylindrical shape with a bottom.
is screwed onto the outer circumferential surface of the cylindrical portion 11 and the torque setting nut member 6 is locked in a predetermined position in the axial direction of the cylindrical portion 11 using the setscrew 61, the bottom wall 60 of the torque setting nut member 6 and Since the spring constant of the disc spring 5 interposed between the distal end surface of the engagement cylinder 4 is set, the torque of the drill 3 that has a correlation with the spring constant of the disc spring 5 is set. It will be done.

Here, the reason why the spring constant of the disc spring 5 and the torque of the drill 3 have a correlation is as follows.
Now, assuming that the drill 3 rotates clockwise as shown by the arrow in FIG. If the torque is the same as or less than the torque of the engagement ring 4, the engagement pin 20 remains in contact with the receiving wall 15 as shown by the solid line in FIG. 4, and is engaged with the tool drive shaft 2. The ring body 4 will rotate in conjunction with the ring body 4, but if the cutting surface of the drill 3 becomes abraded, the cutting resistance increases, and the torque of the tool drive shaft 2 becomes greater than the torque of the engagement ring body 4 (the tool The rotational speed of the drive shaft 2 is
), the tool drive shaft 2 rotates counterclockwise relative to the engagement ring 4 by that difference.

When the tool drive shaft 2, that is, the engagement pin 20 attempts to rotate relative to each other, it rides on the pressing surface 41, and the component of the pressing force generated at that time in the axial direction of the tool head body 1 causes the engagement ring to rotate. body 4
4, but if the component force is equal to or less than the biasing force of the disc spring 5, the engagement will still occur. The pin 20 is the receiving wall 15
Since the engagement pin 20 is pressed against the engagement pin 20, relative rotation of the engagement pin 20 is prevented. Therefore, by setting the spring constant of the disc spring 5 to an appropriate value, it is possible to set the torque of the drill 3 such that the tool drive shaft 2 does not rotate relative to the engagement ring 4. In other words, the spring constant of the disc spring 5 and the torque of the drill 3 have a certain correlation.

Then, the torque setting of the drill 3, that is, the disc spring 5
As a means for appropriately setting the spring constant of the torque setting nut member 6, as shown in FIG. A cursor 16 is engraved on the corresponding outer peripheral surface. In this way, the torque setting of the drill 3 can be set to a desired value without error by visual inspection by the operator.

Note that this torque setting value is selected in advance to be an appropriate value depending on the type of cutting tool, the material of the workpiece W, and the like.

Thus, in the above configuration, the main shaft is rotated,
When feed is applied to this, the drill 3 rotates via the tool head body 1 and the tool drive shaft 2, and the workpiece W can be cut. When wear or the like occurs on the cutting surface of the drill 3, cutting resistance increases, and the torque of the drill 3 becomes larger than the set value, the tool drive shaft 2 retracts to the proximal end side as described above. Since the drill 3 will come off from the work W as a result of this, breakage of the drill 3 can be reliably prevented. In addition, in FIG. 1, the amount of retraction of the tool drive shaft 2 and the drill 3 is indicated by virtual lines.

In addition, when processing the workpiece W using the tool head of the present invention as described above, a means is provided to detect the retraction of the tool drive shaft 2 or the drill 3 toward the base end side and to report this to the machine tool. This is desirable for implementation. In other words, if such a means is provided, the machine tool will be stopped after the drill 3 is moved in and out, so subsequent measures can be taken quickly and power loss etc. can be prevented. It is from.

As one embodiment of the above-mentioned means, a ring sensor that detects the conduction/non-conduction state between the drill 3 and the workpiece W can be considered. Further, as another embodiment, a touch sensor or the like that comes into contact with and detects the proximal end of the retracting tool drive shaft 2 can be considered.

In addition, in the above embodiment, the drill 3 is used as the cutting tool.
Although the description has been made regarding the case where a cutting tool is used, it goes without saying that the present invention can be similarly applied to other cutting tools such as end mills. Further, in the embodiment described above, the disc spring 5 is used as the spring member that urges the engagement ring 4 toward the proximal end, but other spring members such as a coil spring may be used instead.

Effects of the Invention In the case of the present invention described above, when the wear etc. that occur in the cutting tool progresses and the cutting resistance, that is, the torque of the cutting tool increases, the cutting tool automatically retracts. By setting the value to a predetermined value, breakage of the cutting tool can be reliably prevented. Therefore, the cutting tool is not wasted and can be used repeatedly by re-sharpening. It also has the significance of paving the way for unmanned cutting processes.

Moreover, according to the present invention, since the tool head itself is equipped with a tool life detection mechanism, there is an effect that the device configuration can be significantly simplified and downsized compared to the conventional example.

[Brief explanation of drawings]

1 to 4 show embodiments of the present invention, FIG. 1 is a longitudinal sectional view of a tool head equipped with a tool life detection mechanism according to the present invention, and FIG. 2 is an exploded perspective view of main parts. 3 are cross-sectional views of essential parts taken along the line AA in FIG. 1, and FIG. 4 is an exploded view for explaining the movement of the engagement pin to separate from the engagement groove. DESCRIPTION OF SYMBOLS 1... Tool head main body, 11... Cylinder part, 13... Engagement groove, 14... Retraction groove, 15... Reception wall, 2... Tool drive shaft, 20... Engagement pin, 21... Retraction spring, 3
...drill, 4...engaging ring, 40...locking claw, 41...
Pressing surface, 5... Belleville spring, 6... Torque setting nut member.

Claims (1)

[Claims] 1. A tool head main body having a cylindrical portion on the distal end side of a shaft portion connected to the main shaft of a machine tool, and one or more engagement grooves provided in the circumferential direction at the distal end portion of the inner circumferential surface of the cylindrical portion. , a retraction groove that is recessed in the same number of grooves as the engagement grooves on the inner circumferential surface and whose distal end side communicates with a part of the engagement groove; and a receiving wall formed at the base end of the engagement groove; a tool drive shaft having a proximal end inserted into the cylindrical part and holding a cutting tool at the distal end; and one or more protrusions formed on the outer peripheral surface of the intermediate part of the tool drive shaft, and the receiving wall. an engagement protrusion that engages with the
The tool drive shaft has one end connected to the tool drive shaft, and has a retraction spring that elastically urges the tool drive shaft toward the base end, and a locking claw that engages with the engagement groove on the base end side. An engaging ring body is attached to the distal end of the cylindrical part so that the engaging convex part is pressed against the receiving wall with a pressing surface formed in a single flow shape in the circumferential direction, and the engaging ring body is attached to the proximal end. and a spring member that applies elastic force to the side,
The engagement protrusion is disengaged from the receiving wall due to fluctuations in torque acting on the cutting tool, and the tool drive shaft is guided by the retraction groove and retracted toward the proximal end side. A tool head equipped with a unique tool life detection mechanism.