JPH042760Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention is a chip breaker mechanism for an annular cutter in a drilling machine that improves the chip evacuation performance of an annular cutter that cuts an annular groove, thereby improving cutting performance. It is related to.

[Prior art]

In general, a twist drill with two cutting blades can be used as a drilling tool, but from the viewpoint of downsizing the rotary drive source for the drilling tool and shortening the cutting time, multiple By using an annular cutter with several cutting blades arranged in parallel in a ring, a relatively narrow area for the desired hole diameter can be efficiently drilled by cutting into an annular groove with multiple cutting blades. be able to.

By the way, chips generated by each cutting blade of the annular blade are discharged from the annular groove in the process of being formed through a plurality of chip discharge grooves formed on the outer circumferential surface of the annular blade in one-to-one correspondence with the cutting blade. However, since the chips discharged outside the annular groove are continuously pushed out, a large amount of chips easily wrap around the outer peripheral surface of the rotatably driven annular cutter. Moreover, the amount of chips that wrap around the outer circumferential surface of the annular cutter increases as the drilling depth of the annular groove becomes deeper, so they immediately block the chip discharge groove, causing the chips to become trapped in the same groove. It gets stuck between the annular groove and the outer wall surface, reducing the chip evacuation function of the annular cutter.
Furthermore, the cutting resistance increases and eventually the drilling operation has to be stopped, in which case the stopped annular cutter is extracted from the workpiece and the chips are manually removed. As a result, it was inevitable that the cutting efficiency would decrease.

Therefore, conventionally, one
Two protrusions are arranged to face the axial direction of the annular cutter, and the chips that are discharged from the annular groove through the chip evacuation groove are brought into contact with the tips of the protrusions and are forcibly bent in the centrifugal direction. Chip breaker mechanism for separating and scattering was patented in JP-A-58-196911, US patent.
It is introduced by specification No. 4514120.

[Problem that the invention attempts to solve]

However, chips ejected from the annular groove during drilling curl and undulate irregularly as cutting conditions change, resulting in slight changes in the cutting thickness. Even if debris comes into contact with the protrusion, it will not break.
A phenomenon occurred in which the outer peripheral surface of the cutter was pushed upward while being wrapped around the annular cutter, and as a result, the chips could not be sufficiently removed from the annular cutter. Once such chips are wrapped around the cutter, new chips become entangled with the wrapped chips, and the amount of the wrapped chips increases cumulatively, resulting in a situation where the chip evacuation function is further deteriorated. When the chips are tightly wrapped around the circular cutter,
As mentioned above, it becomes necessary to interrupt the drilling process, and it becomes necessary to remove chips before the next process, which not only takes extra time but also causes injury to hands and fingers from sharp chips. There was also a fear.

The present invention was developed in view of the problems mentioned above with conventional chip breaker mechanisms.It prevents chips from tightly wrapping around the annular cutter and improves chip evacuation performance. It is an object of the present invention to provide an improved chip breaker mechanism.

[Means for solving problems]

The chip breaker mechanism of the present invention has a plurality of cutting blades on the lower edge of a rotatably driven annular main cylinder, and chips cut by the individual cutting blades are formed on the outer peripheral surface of the main cylinder. In order to solve the above-mentioned problem of a drilling machine that has an annular cutter that guides upward from a chip discharge groove, a comb-shaped piece that scrapes off chips entangled with the annular cutter is used as a means to solve such problems. A configuration is adopted in which the tips of the teeth are erected so as to intersect with the outer circumferential surface of the annular cutter, and the tips of the teeth of the comb-shaped pieces are directed near the outer circumference of the annular cutter.

[Effect]

When the drilling machine is started and cutting work begins, chips become entangled with the outer circumferential surface of the annular cutter.
At this time, the chips are subjected to a force in the centrifugal direction, so in the chip breaker mechanism of the present invention, a portion of the chips first hits the tips of the teeth of the comb piece from below and becomes entangled between the teeth of the comb, and also creates new chips. If any debris comes into contact with the comb-teeth protrusions, they will be entangled together, and at the same time, as the annular cutter rotates, it will be combed and the chips will be torn off. Sequentially scrape over a wide area in the axial direction. As a result, the long chips generated by cutting no longer wrap around the outer circumferential surface of the annular cutter, but are cut into short pieces and moved to the chip discharge groove of the annular cutter, where they continue along the same groove. It then moves above the annular cutter and separates from the outer peripheral surface of the cutter.

〔Example〕

A drilling machine to which the chip breaker mechanism of the present invention is attached is shown, for example, in FIG.

First of all, this drilling machine has an electromagnetic attraction base 2 at the bottom of a frame 4, which is electromagnetically fixed to a desired position of a workpiece 1 having magnetic properties, and an electric drill 3 at the top of the frame 4. The basic structure is a point installed so that it can be raised and lowered,
A cutter arbor 6 is fixed to the spindle 5 of the electric drill 3 concentrically, and the middle part of the cutter arbor 6 is supported by a holder 7 protruding from the front part of the electromagnetic attraction base 1.
An annular cutter 8 is fixed to the lower end of the blade. A pilot pin 9 elastically biased downward is housed in the axis of the cutter arbor 6 so as to be freely protrusive and retractable from the lower end of the annular cutter 8 so as to function as a center of the annular cutter 8 and a pin for discharging slag.

The electric drill 3 can be lifted and lowered manually by rotating an lifting operation handle 10 provided on the frame 4, or by driving an automatic feed unit 11 consisting of a motor and a special speed reducer (for example, a harmonic drive mechanism). Or it is done automatically. In addition, a stabilizer 12 is installed on the frame 4 in order to prevent the front part of the electromagnetic attraction base 2 from easily lifting up due to the reaction force when the annular cutter 8 cuts the workpiece 1 as the electric drill 3 descends. A so-called spike pin 13 is installed on the rear side of the workpiece 1 by screw fitting, or a so-called spike pin 13 is installed on the surface of the workpiece 1 to prevent the electromagnetic adsorption base 1 from sliding sideways due to the rotational torque of the annular cutter 8. or set it up nearby.

As shown in FIGS. 1 and 2, the annular cutter 8 has a plurality of cutting blades 15 at the lower end periphery of the main cylinder 14, and each cutting blade 15 has a plurality of cutting blades 15. 1 by a chip discharge groove 16 provided to guide chips upward to the main cylinder 14.
They are formed in a one-to-one correspondence so as to be guided above the main cylinder 14 . Each cutting blade 15 has an annular groove 1 formed in the workpiece 1 by the cutting action of the annular blade 8.
The inner cutters that cut the inner circumferential side and the outer cutters that cut the outer circumferential side of the cutters 7 form one group and are regularly arranged.

The chip breaker mechanism 20 of the present invention is attached, for example, to the front part of a drilling machine configured as described above so as to face the outer circumferential surface of the annular cutter 8, as shown in FIGS. 1 and 2.

In this chip breaker mechanism 20, comb-shaped pieces 21 for scraping chips 18 entangled on the outer peripheral surface of the annular cutter 8 are fixed at a predetermined interval so as to be orthogonal to the axial direction of the annular cutter 8. Tip 2
1' is directed close to the outer peripheral surface of the annular cutter 8.

This chip breaker mechanism 20 has a comb-shaped piece 21, which is the main part, as shown in FIG.
The comb tip 21' may be fixed perpendicularly to the front surface of the frame 2 so as to be parallel to the imaginary tangent line of the annular cutter 8, or the comb tip 21' should face the axis of the annular cutter 8 (see the two points in Figure 2). (see dashed line and FIG. The optimum spacing is determined by providing elongated holes 22 or other means.

Next, the operation of the above embodiment will be explained.

When the drilling machine is started and the drilling operation progresses with the annular cutter 8, as the annular cutter 8 penetrates deeper into the workpiece 1, the chips 18 protrude from the chip evacuation groove 16 and the annular cutter 8 penetrates deeper into the workpiece 1. Eventually, these chips 18, along with new chips 18 entangled therein, collide with the comb-shaped piece 21, and are successively scraped off as the annular cutter 8 rotates. That is, the chips 18 entangled on the outer peripheral surface of the annular cutter 8 are spread in the centrifugal direction by the centrifugal force of the cutter 8, so that they are uniformly spread over the wide surface of the comb-shaped piece 21, and the combing action by the comb-shaped piece 21 is New chips 18 entangled with the annular cutter 8 are also torn off and scraped off as they are. Therefore, even if the chips 18 become entangled with the annular cutter 8, they will be cut off and separated from the annular cutter 8 before they are wrapped around the annular cutter 8 many times or tightly, and the chips 18 will not clog the chip discharge groove 16. , the chips 18 are in the annular groove 17 in the middle of cutting.
The chips are smoothly discharged along the chip discharge groove 16.

As described above, the chips 18 entangled with the annular cutter 8 spread outward due to the centrifugal force, and the chips 18' that are scraped off the annular cutter 8 and remain at the tip of the comb-shaped piece 21 are transferred to the annular cutter 8. By exhibiting the function of scraping off new entangled chips 18, there is no need to adjust the distance between the tip of the comb-shaped piece 21 and the outer periphery of the annular cutter 8 in accordance with the outer diameter of the annular cutter 8. However, in the case of a drilling machine that can use annular cutting tools 8 of various outer diameters in which the maximum drilling diameter and the minimum drilling diameter are significantly different, in order to avoid contact between the annular cutting tool 8 and the comb piece 21, the third As shown in the figure, it is desirable to bring the piece 21 closer to or away from the annular cutter 8 by a required amount.

The comb-shaped piece 21 is usually made of metal, but is not limited to metal as long as it is hard. In addition, the number and thickness of the comb teeth constituting the comb-shaped piece 21, as well as the spacing between the comb teeth, are determined by cutting conditions such as the cutting performance of the annular blade 8, the thickness and width of chips generated, and the cutting speed. However, in particular, the spacing between the comb teeth must not allow chips to remain unnecessarily in the comb-shaped piece 21, that is, it only needs to satisfy the condition that a smooth combing action is performed. .

[Effect of idea]

The chip breaker mechanism of the present invention has the following effects.

(1) The chip breaker mechanism of the present invention is capable of removing chips that pass through the chip discharge groove of the annular cutter and become entangled with the outer periphery of the annular cutter, or with new chips that have become entangled afterwards. By combing, scraping and cutting from the annular cutter, it is possible to prevent the chips from getting entangled with the annular cutter or the comb piece itself. Therefore, it is possible to prevent the phenomenon in which the chips that have once become entangled with the annular cutter become tightly entwined in multiple layers.

(2) Since the chips are not tightly wrapped around the annular cutter, it is not necessary to remove the chips before the next drilling process as in the past, and the injuries caused by sharp chips that were often experienced in the past are also avoided. be able to.

(3) When chips become entangled with the annular cutting tool, the chips spread outward due to the centrifugal force generated by the rotation of the cutting tool, but the chip breaker mechanism of this invention effectively prevents this phenomenon. Since the combing function can be improved by using this method, it is possible to remove chips extremely effectively without having to precisely adjust the distance between the tip of the comb piece and the outer circumferential surface of the annular cutter depending on the diameter of the annular cutter. It is now possible to remove the holes, and the setup work performed prior to drilling can also be simplified.

(4) During drilling work, the chip evacuation groove is no longer blocked by chips, and chips are smoothly discharged from the annular groove in the middle of cutting along the chip evacuation groove, resulting in always good cutting. The cutting edge of the annular cutter can be prevented from being damaged.

[Brief explanation of drawings]

The drawings show one embodiment of the chip breaker mechanism for an annular cutter in a drilling machine according to the present invention.
3 is a plan sectional view showing another method of attaching the comb-shaped piece, and FIG. 4 is a side view showing an example of a drilling machine to which the present invention is applied. 8... Annular cutter, 14... Main cylindrical body, 15... Cutting blade, 16... Chip discharge groove, 17... Annular groove,
18... Chips, 20... Chip breaker mechanism,
21...comb-shaped piece, 21'...comb tooth tip.

Claims (1)

[Scope of utility model registration request] The rotatably driven annular main cylinder has a plurality of cutting blades on the lower edge thereof, and a chip discharge groove is formed on the outer peripheral surface to guide the chips cut by the individual cutting blades upward to the main cylinder. An annular cutting tool for a drilling machine, which is attached to a drilling machine having an annular cutting tool, in which a comb-shaped piece is erected in the vicinity of the annular cutting tool, with the tips of the teeth facing in an intersecting state with respect to the outer circumferential surface of the annular cutting tool. chip breaker mechanism.