JPH0244645B2 - 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 first and second conventional examples described above, 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 to solve the problems of the prior art, and provides a tool head equipped with a tool life detection mechanism that can accurately detect the tool life itself. The purpose is to

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 cylindrical shape with the proximal end side closed, the proximal end part being inserted into the cylindrical part, and the distal end part a tool drive shaft for holding a cutting tool; a means for supplying working fluid into the inside of the tool drive shaft; The proximal end has an engaging protrusion that engages with the engagement groove, and a retaining pawl that engages with the engaging groove, and a pressing surface formed in a one-sided shape in the circumferential direction of the retaining pawl engages the engaging convex portion. an engaging ring attached to the distal end of the cylindrical portion so as to press the retaining wall against the receiving wall; and a spring member that elastically biases the engaging ring toward the proximal end. Due to fluctuations in the torque acting on the tool, the engagement protrusion is disengaged from the receiving wall, and the tool drive shaft is guided by the retraction groove and retracted toward the proximal end side.

Function When the cutting tool's cutting edge wears out 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 engaging protrusion provided on the tool head rotates (slips) relative to the engaging ring which rotates in conjunction with the tool head body. Then, as shown by the imaginary line in FIG. 4, the engagement pin 20 (engagement convex portion)
This pushes the engagement ring 4 toward the distal end against the biasing force of the disc spring 5 (spring member) and the internal pressure P of the working fluid that presses the tool drive shaft toward the proximal end (see Figure 1). As a result, the engagement pin 20 separates from the receiving wall 15 and jumps into the retraction groove 14. Even in this state, the biasing force and internal pressure P still act on the engagement pin 20, that is, the tool drive shaft, so that the tool drive shaft, that is, the cutting tool, is guided by the retraction groove 14 toward the proximal end. You will be leaving.

Embodiments Hereinafter, embodiments of the present invention will be described based on the drawings.
Fig. 1 is a longitudinal sectional view showing a tool head equipped with a tool life detection mechanism according to the present invention, Fig. 2 is an exploded perspective view of the main parts, and Fig. 3 is the main part taken along the line AA in Fig. 1. FIG. 4 is a developed view for explaining the detachment operation of the engagement pin from the receiving wall.

This tool head consists of a tool head main body 1 formed by connecting a cylindrical cylindrical portion 11 to the distal end side of a taper shank 10 provided on the proximal end side corresponding to the left side in the figure, using a bolt 24, and A support cylinder 8 that is fitted externally on the proximal end side and rotatably supports the tool head main body 1, a support member 9 that is connected to a part of the outer peripheral surface of the support cylinder 8, and a support member 9 that is fitted on the proximal side in the cylindrical part 11. It has been inserted,
Hollow tool drive shaft 2 that holds a drill 3 at the tip
, an engagement ring 4 attached to the tip of the cylindrical portion 11 and fitted onto the outer circumferential surface of the intermediate portion of the tool drive shaft 2; and a torque ring attached to the outer circumferential surface of the tip of the cylindrical portion 11. The setting nut member 6 is connected to the main shaft 7 of the machining center.

Specifically, this connection is performed by pushing the taper shank 10 into the fitting hole 70 of the main shaft 7. At this time, the positioning pin 90 provided on the proximal end side of the support member 9 is simultaneously pushed into the pin groove (or hole) 101 of the positioning block 100, and the support tube 8 is reliably prevented from rotating. There is. Thus, due to this connection mode, the workpiece W of the drill 3
Positioning will be performed for. In addition,
92 is a casing that slidably supports the positioning pin 90, and 93 is a spring that always biases the positioning pin 90 toward the base end side.

A fluid passage 102 is formed in communication with the base end side of the pin groove 101 of the positioning block 100, through which a cooling fluid such as cutting oil, air, oil mist air, etc. supplied from a pump (not shown) flows. Further, a fluid passage 91 is provided inside the positioning pin 90, and when the positioning pin 90 is fitted into the pin groove 101, both fluid passages 102 and 91 are brought into communication. The distal end side of the fluid passage 91 includes a communication hole 94 provided at the distal end of the casing 92, a fluid passage 95 provided within the support member 9 to communicate with the communication hole 94, and a fluid passage formed on the inner peripheral surface of the support cylinder 8. Annular fluid passage 8
Connected to 0. Furthermore, the fluid passage 80 is connected to the cylindrical portion 1
The proximal end side of the cylindrical portion 1 communicates with a fluid passage 16 provided in the radial direction of the cylindrical portion 1.
The tool drive shaft 2 is connected to a fluid passage 22 similarly provided at the base end of the tool drive shaft 2 that rotates in conjunction with the tool drive shaft 1 .

Thus, cooling fluid is supplied from the pump to the inside of the tool drive shaft 2 through these passages as indicated by arrows in the figure. This cooling fluid is supplied to the fluid passage hole 3 provided inside the drill 3.
0 to the cutting edge side of the work W and the cutting surface of the drill 3 that is cutting it, and also causes wear etc. on the cutting surface of the drill 3 as will be described later. As the resistance increases,
When the torque of the tool drive shaft 2 that holds the drill 3 increases, it functions to pull the tool drive shaft 2 toward the base end.

Next, details of the cylindrical portion 11 and the tool drive shaft 2 will be explained in order. 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 in the circumferential direction with an appropriate width. Engagement groove 13,
On the proximal end side of 13, recessed lead-in grooves 14, , 14 having a narrower width than this are provided. 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 retaining wall 15 is formed in the remaining part of the engagement groove 13. It's summery.

A proximal end of a cylindrical tool drive shaft 2 is inserted into the cylindrical portion 11 and connected thereto. The proximal end of the tool drive shaft 2 is closed by a proximal wall 21 . The proximal wall 21 is normally located on the distal side of the proximal end surface 17 of the cylindrical portion 11, and is located between the proximal wall 21, the proximal end surface 17, and the connecting hole 10a provided on the inner surface of the distal end portion of the taper shank 10. A space 18 is formed in the space 18. A plurality of air vent holes 19 (only one is shown in the illustrated example) are provided in the portion of the tapered shank 10 corresponding to the connection hole 10a in the radial direction.
has been drilled.

The tool drive shaft 2 is attached to be rotatable in conjunction with the cylindrical portion 11 and 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, which will be described below. This causes the tool drive shaft 2 to be pressed against the cylindrical portion 11, that is, the drill 3
The tool head body 1 rotates in conjunction with 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 The ball only needs to be provided on the outer circumferential surface, so 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. Further, the number of these is not limited to two, and may be one, or three or more. 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.

On the other hand, when the tool drive shaft 2 rotates relative to the engagement ring body 4 as shown in FIG.
is detached from the receiving wall 15, jumps into the retraction groove 14, and then slides toward the proximal end. This sliding movement is performed by the cooling fluid. That is, this is because the cooling fluid supplied to the interior of the tool drive shaft 2 as described above constantly presses the proximal wall 21 toward the proximal end due to its internal pressure P.

However, by performing such a sliding operation,
A relationship is established between the tool drive shaft 2 and the cylindrical portion 11 that allows the tool drive shaft 2, which corresponds to a piston, to slide against the cylindrical portion 11, which corresponds to a cylinder, using the cooling fluid as a working fluid. Become.

Note that the air in the space 18 will be compressed due to this sliding operation, but the air vent hole 1 described above will be compressed.
Since the compressed air is discharged to the outside through the tool 9, there is no risk of the tool drive shaft 2 being pushed back to the tip side.

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, on the proximal end side of the engaging ring body 4, locking pawls 40, 40 of an appropriate width are formed to protrude and engage with the aforementioned engaging grooves 13, 13, respectively.
0 and 40 are provided with pressing surfaces 4 for pressing the protrusions at both ends of the engagement pin 20 against the receiving walls 15 and 15.
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 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, 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
As shown by the imaginary line in FIG. 4, the component force is pushed toward the distal end due to the biasing force of the disc spring 5 and the internal pressure P of the cooling fluid. If the sum is equal to or less than the sum of the above, the engagement pin 20 is still pressed against the receiving wall 15, so that 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 11a is carved 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,
A drill 3 is rotated via a tool head main body 1 and a tool drive shaft 2 that feed the drill, so that a 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 base end side as described above. As the drill 3 moves back and forth from the workpiece W by the stroke S shown in the figure, breakage of the drill 3 can be reliably prevented.

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 proximal 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 suppressed. It is from.

As one embodiment of the above-mentioned means, a ring sensor that detects conduction or non-conduction between the drill 3 and the workpiece W can be considered. In another embodiment, when the cutting resistance increases and the tool drive shaft 2 retracts toward the proximal end, the fluid passage 16 and the fluid passage 22 are disconnected from each other, thereby reducing the load on the pump. Therefore, it is conceivable to adopt a configuration in which this drop in the pump pressure is detected by an appropriate detection means.

In addition, in the above embodiment, the drill 3 is used as the cutting tool.
Although the present invention has been described with reference to the case in which the present invention is used, it goes without saying that the present invention can be similarly applied to other cutting tools such as end mills, and can also be applied to machine tools other than machining centers, such as drilling machines and milling machines. .

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.

Furthermore, in the above embodiment, a so-called side-through type embodiment is adopted in which the cooling fluid is supplied from the side of the tool drive shaft 2. ,
A so-called spindle-through type embodiment is adopted in which fluid passages are provided between the exteriors, and the tips of these fluid passages are communicated with the fluid passage 16 to supply cooling fluid to the inside of the tool drive shaft 2. Good too.

Furthermore, in the above embodiment, the cutting tool has a fluid communication hole inside the tool. Although this embodiment uses a so-called oil hole type tool to effectively cool the cutting edge side of the cutting tool, it goes without saying that the present invention can also be applied to ordinary cutting tools. Alternatively, an embodiment may be adopted in which cooling fluid is jetted toward the cutting edge side of the cutting tool using a nozzle or the like to cool the cutting tool.

Effects of the Invention In the case of the present invention described above, when the wear etc. occurring on 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 showing a tool head equipped with a tool life detection mechanism according to the present invention, and FIG. 2 is an exploded view of the main parts. FIG. 3 is a sectional view of the main part taken along line AA in FIG. 1, and FIG. 4 is a developed 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, 16... Fluid passage, 2... Tool drive shaft, 20... Engagement pin, 21
... Base end wall, 22 ... Fluid passage, 3 ... Drill, 4 ... Engagement ring, 40 ... Locking claw, 41 ... Pressing surface, 5 ... Belleville spring, 6 ... Torque setting nut member, 7 ... Main shaft, 8
...Support tube, 9...Support member, 90...Positioning pin,
100...Positioning block.

Claims (1)

[Scope of 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 recesses provided in the circumferential direction at the distal end portion of the inner circumferential surface of the cylindrical portion. an engagement groove formed on the inner circumferential surface, a retraction groove formed in the same number of grooves as the engagement grooves, and whose distal end side communicates with a part of the engagement groove; and a retraction groove formed at the proximal end of the engagement groove. a receiving wall; a tool drive shaft having a cylindrical shape with a closed base end, the base end of which is inserted into the cylindrical portion, and holding a cutting tool at the distal end; and an interior of the tool drive shaft. means for supplying working fluid to the tool drive shaft; one or more engaging protrusions formed protruding from the outer circumferential surface of the intermediate portion of the tool drive shaft and engaging with the receiving wall; and engaging protrusions engaging with the engaging groove. A locking claw is provided on the proximal end side, and a pressing surface of the locking claw formed in a single flow shape in the circumferential direction presses the engagement convex portion against the receiving wall so as to press the engagement protrusion against the receiving wall. an attached engagement ring;
a spring member that elastically urges the engagement ring toward the proximal end, and the engagement protrusion detaches from the receiving wall due to fluctuations in torque acting on the cutting tool, and the tool drive shaft rotates. A tool head equipped with a tool life detection mechanism, characterized in that the tool head is configured to retract toward the proximal end side while being guided by the retraction groove. 2. The cutting tool is a cutting tool equipped with a fluid communication hole that communicates with the inside of the tool drive shaft, and the working fluid is ejected toward the cutting edge side through the fluid communication hole. A tool head comprising a tool life detection mechanism according to claim 1.