JPS6368304A - Drill device - Google Patents

Abstract

PURPOSE:To control the length of cut chips to a predetermined value before they are discharged, by providing at least three rolling elements on the opposite surface of a thrust ring while their relative positions are limited, and by forming, on the orbit of the rolling elements in the opposite surface of the thrust ring, a plurality of recesses in which all rolling elements are engaged, simultaneously, at an instant time. CONSTITUTION:By being subjected to a load in the thrust direction of a drill spindle 10, three rolling elements 17, 17, 17 are fitted simultaneously into recesses 20, respectively, at an instant time for every predetermined rotation of the spindle 10. At that time, the spindle 10 exerting an advancing force to a drilling tool along the thrust directions is axially displaced slightly in accordance with the depth of the recesses 20. Thereby the cutting by the drilling tool is instantly ceased so that cut chips are cut into a predetermined length for every predetermined rotation of the drill spindle 10 before being discharged from the drilled hole.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a drilling device with improved chip discharge performance using a drilling tool.

[Prior art]

A drilling tool such as an annular cutter or a twist drill that has a cutting edge at its tip has a groove connected to the cutting edge on its outer periphery, and chips generated during the drilling operation are discharged out of the hole along the groove. The chips discharged out of the hole in this manner vary depending on the material to be drilled, the cutting speed, the feed rate of the drilling blade, etc., but usually they are continuously discharged over a predetermined length.

By the way, if the feed speed of the drill spindle is kept almost constant and thrust is applied to the drilling tool, the length of the cut that is continuously ejected out of the hole is relatively long, and the cut is caused by the increase in its own weight and ejection resistance. Chip discharge performance deteriorates, chips get stuck between the hole and the drilling tool, and the resulting increased cutting resistance impairs free-cutting performance, reducing drilling efficiency, and even causes the cutting blade to become abnormal. There was a problem that the cutting edge would become dull due to frictional heat. As a simple countermeasure in this regard, conventionally, a barrier member is fixed to the casing located above the drilling tool so that it can come into contact with a continuous series of chips, and the chips come into contact with the barrier member. A technique has been proposed in which chips are forcibly broken off by the impact or resistance of the cutting tool, but if such a barrier member is installed near the drilling tool, it not only obstructs the drilling process but also causes the chip to form a spiral shape. There is no guarantee that the chips that are continuously discharged as they undulate and undulate will definitely come into contact with the barrier member.
It is also possible to use a gun drill that uses that pressure to flush out the cut shoulder along with the cutting oil, but in that case, a special machine tool and tool head are required, and a drill such as a portable one or a relatively small drill press is required. Not applicable to equipment.

[Problem that the invention seeks to solve]

When the above-mentioned barrier member is used as a simple means for forcibly cutting the cut shoulders that are continuously discharged from the hole,
Not only does this hinder the drilling work, but there is also the problem that the chips tend to be continuously discharged without contacting the barrier member, and the present invention fundamentally solves these problems.
It is an object of the present invention to provide a drilling device that can control chips to a predetermined length and discharge them from a hole.

[Means for solving problems]

As a means for solving the above-mentioned problems, the present invention provides a drill spindle equipped with a drilling tool attachment part at the tip.
It is supported on the casing so that it can reciprocate in the axial direction, and
A pair of thrust rings are fixed to the drill spindle and the casing so as to face each other, and furthermore, at least three rolling elements are fixed to the opposing surfaces of the thrust rings to regulate their relative positions, and the casing is fixed to the drill spindle. A structure is adopted in which the thrust ring fixed to the roller is interposed so that it can rotate at a fixed position, and a plurality of recesses are formed on the rolling track of the rolling element, in which all the rolling elements temporarily stand at the same time. It is something to do.

[For production]

In the drill device of the present invention, when the rolling elements that roll under the thrust direction load of the drill spindle temporarily fit into the respective recesses at the same time every predetermined rotation of the spindle, at that time, the rolling elements along the thrust direction The drill spindle, which is applying advancing force to the drilling tool, is slightly displaced in the axial direction in response to the depth of the recess, thereby instantaneously stopping cutting by the drilling tool. Each rotation cuts chips to a predetermined length and discharges them from the hole.

〔Example〕

As shown in FIG. 4, the drill device of this embodiment has an electromagnetic adsorption base 2 at the bottom of a drill stand 3, which is fixed to a desired position of a workpiece 1 by electromagnetic adsorption. On the other hand, a punching machine 5 is supported, which can be moved forward and backward with respect to the workpiece by rotating an elevator handle 4 and operating an automatic feed unit (not shown).

As shown in FIG. 1, the drilling machine 5 has an electric motor (not shown) built into a casing 6, and the rotation of the motor shaft 7 is slowed down by two sets of feed gears 8A to 8D, and has an annular cutter or the like at the tip. Drill spindle 10 to which a drilling blade 9 can be attached and detached
to communicate.

The tip of the drill spindle 10 protrudes from a housing block 11 screwed and fixed to the lower end of the casing q, and the middle part of the drill spindle 1o is pivotally supported by a radial needle bearing 12 fitted and fixed to the housing block 11. The upper end of the drill spindle 10 is pivotally supported by a radial needle bearing 14 provided on a partition plate 13 of the casing 6. The portion of the drill spindle 10 that can be contacted and supported by the pair of radial needle bearings 12 and 14 is set to be slightly longer than the axial length of the bearings, so that the drill spindle 10 has a slight axial length. It is installed so that it can be moved back and forth.

Reference numeral 15 denotes a flange-shaped first thrust ring which is fixed to the outer circumference of the drill spindle 1o located above the radial needle bearing 12 so as to be able to rotate integrally therewith. A disk-shaped second thrust ring 16 whose center hole is loosely fitted into the drill spindle 10 is fitted and fixed to the casing 6 via its outer peripheral surface.

On the lower end surface of the second thrust ring 16, as shown in FIG.
．． 17 at different distances Di, D2 . D3
(However, Di>D2>D3), the center is centered on the ball accommodation hole 18 that individually accommodates the thrust balls 17, 17, 17 in a rollable manner on the upper end surface of the first thrust ring 15. They are all set at different distances from each other. Further, on the upper end surface of the first thrust ring 15, rolling tracks LL, L2, . On L3,
Relative angular position θ1 between the ball accommodation holes 18. θ2.
The spherical recesses 20 having a relationship equal to θ3 with respect to the center C1 of the thrust ring 15 are all formed to have the same depth,
Thereby, the 3 rolling on the first thrust ring 15
The thrust balls 17, 17, 17 are one of the first thrust rings 15 that rotate together with the drill spindle 10.
Once per rotation, temporarily and simultaneously each recess 2
0.

The first thrust ring 15 receives an elastic force from a compression coil spring 24 interposed between the first thrust ring 15 and the upper end surface of the radial needle bearing 12 via a spacer 23.
It is urged in the direction d away from the workpiece integrally with the drill spindle 10. Therefore, the first thrust ring 15 has its upper end surface connected to the thrust ball 17.
By elastically pressing the ring 15, the drill spindle 1o, which is integrated with the ring 15, is supported in its thrust direction.

Note that the first thrust ring 15 has different rolling tracks LL, L2, . L3 is elastically pressed by three thrust balls 17, 17, 17 and supported at three points, but if the rolling trajectories of each thrust ball 17 are different, an eccentric load is applied to the thrust ring 15. Therefore, the loads acting on the installation positions of the respective thrust balls are balanced at the axial center position of the drill spindle 10. The centers of gravity of the center C1 of the first thrust ring 15 and the center C2 of the second thrust ring 16 coincide with each other. With such consideration, a pair of thrust rings 15 and 16 and three thrust balls 1
7, 17, and 17 support the drill spindle 10 stably in its thrust direction without being subjected to eccentric rotation or tilting force regardless of the rotation speed, and also support the individual thrust balls 17 and their rolling tracks. Prevent uneven wear.

3 which elastically supports the first thrust ring 15 at three points;
When thrust balls 17, 17.17 are simultaneously fitted into the recess 20 formed in the ring 15, the drill spindle 10 integrated with the first thrust ring 15 has a depth corresponding to the depth of the recess 20. The depth of the recess 20, which is retracted by a distance (displaced upward in FIG. 1), is set to be approximately equal to the maximum allowable thickness of the chips to be scraped off by the punching blade 9. The maximum allowable thickness of chips is determined in relation to the maximum rotational speed of the drill spindle 10 and the maximum allowable feed rate of the drilling machine 5, which the drill device has as its maximum drilling capacity, and the material of the workpiece 1. be done. Therefore, when the thrust balls 17, 17, 17 are placed in the recess 20 due to the feeding force of the drill spindle 10 acting on the drilling tool 9 during drilling, cutting by the drilling tool 9 is momentarily stopped. , whereby the length of the chip is controlled to a cutting length determined approximately by one revolution of the drill spindle 10.

The drilling tool 9 is an annular cutter, and is removably fixed to the cutter arbor 25 of the drill spindle 10 with a set screw 26. A pilot pin 27 is located on the axis of the drilling tool 9 on the lower end surface of the drilling tool 9. It is inserted so that it can appear freely. When the drilling tool 9 is attached to the drill spindle 10, the head of the pilot pin 27 is pressed by the press piece 29 which receives the elastic force of the compression coil spring 28 housed in the cutter radius 25 of the drill spindle 10, and its In this state, the tip of the pilot pin 27 protrudes from the lower end surface of the punching tool 9 and
In the middle of drilling, the cutter arbor 25 is displaced upward by idling while in close contact with the surface of the workpiece, more precisely, the surface of the core, in response to the feed of the drill spindle 10. When the drilling machine 5 returns to its upward position after completing the drilling process, the cut pieces are pushed out from inside the drilling blade 9 by the elastic force of the compression coil spring 28.

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

The first thrust ring 15 supports the drill spindle 10 integrated with the second thrust ring 15 in its thrust direction by elastically pressing the three thrust balls 17 housed and supported in the second thrust ring 16. . When the drill spindle 10 is driven to rotate, the three thrust balls 17, 17, 17 whose surfaces partially protrude from the ball accommodation hole 18 of the second thrust ring 16 roll differently on the first thrust ring 15. Trajectory LL, L2. The rolling orbits LL, L2 .
At the same time, it fits into the recess 20 provided on L3. Then, the drill spindle 10 and the first
The thrust ring 15 moves in the axial direction by a distance corresponding to the depth of the recess 20, displacing upward in FIG. 1, and changing from the state shown in FIG. 1 to the state shown in FIG. 3. Therefore, during the drilling process, the drill spindle 10, which applies a downward feeding force along the thrust direction to the drilling blade 9 via the rotary scraping handle 4 and the automatic feed unit (not shown), increases the depth of the recess 20. When the sliding displacement occurs in response to this, the movement corresponds to substantially stopping the feed of the drilling tool 9 in the cutting direction, and the amount of displacement corresponds to the maximum allowable amount of chips scraped off by the drilling tool 9. Since it is almost the same as the thickness dimension, the cutting by the drilling tool 9 is stopped instantaneously at the same time, and the chips are controlled to the cutting length determined by approximately one rotation of the drill spindle 10, and the chips are stopped during the drilling process. It is intermittently discharged from the hole.

Although the present invention has been described above in detail based on one embodiment, the present invention is not limited to the above embodiment, and can be modified in various ways without departing from the gist thereof.

For example, in the above embodiment, one revolution per revolution of the drill spindle.
Although the spindle is configured to be displaced backward at a rate of 100.degree., when an annular cutter with a relatively large cutting diameter is applied, each of the rolling raceways LL, L2. L3
In addition, two recesses 20 into which three thrust balls 17 can fit simultaneously are formed, and the drill spindle 10 is configured to be displaced twice in the direction opposite to the tip for each revolution of the drill spindle 10. , as shown in Figure 5, 3
The three thrust balls have a common rolling track, and a set of recesses into which three thrust balls can fit simultaneously is formed on the track, and the drill spindle is rotated three times in the axial direction for each revolution of the drill spindle. It can also be configured to be slidably displaced, and by appropriately setting and combining the numbers of thrust balls, rolling tracks, and recesses, the number of displacements of the drill spindle relative to the number of rotations of the drill spindle can be varied to 1 or more. It is possible.

In addition, the first thrust ring and the second thrust ring in the above embodiment
Although the opposing surfaces of the thrust rings are configured to face in the thrust direction of the drill spindle, as shown in FIG. A second thrust ring 33 is fixed to the casing 6, and has a rolling raceway groove 32 on its inner peripheral surface in which the thrust ball 17 protruding from the ball accommodation hole 3o rolls, and is further fixed to the casing 6. A spherical recess 34 into which the thrust ball 17, which is urged upward by receiving the elastic force of 24, can be inserted is formed downward at a predetermined position on the upper end edge of the rolling raceway groove 32. It is also possible to do so.

Furthermore, the rollers interposed between the pair of thrust rings are not limited to thrust balls, but may be changed to tapered rollers.
Further, the rolling element may be accommodated in either of the pair of thrust rings.

Further, the drilling blade attached to the tip of the drill spindle is not limited to an annular cutter, but may be a twist drill.

Although the above embodiment describes the case where the present invention is applied to a drill device equipped with a portable electromagnetic attraction base, the present invention can also be applied to a small drilling machine or an electric drill.

〔Effect of the invention〕

In the drill device of the present invention, a drill spindle, which is provided with a mounting portion of a drilling tool at its tip, is supported on a casing so as to be movable back and forth in the axial direction, and a pair of thrust rings are provided on the drill spindle and the casing so as to face each other. Further, at least three rolling elements are interposed on opposing surfaces of the thrust ring so as to regulate their mutual relative positions and to be rotatable at fixed positions of the thrust ring fixed to the casing. , on the rolling track of the rotor.

A plurality of recesses are formed in which all the rolling elements are temporarily combined at the same time, and the rolling elements, which roll under the thrust load of the drill spindle, fall into their respective recessed parts at the same time every predetermined rotation of the drill spindle. At that time, the drill spindle was slightly displaced in response to the depth of the recess.
According to the invention.

Cutting by the drilling tool can be stopped instantaneously and accurately every time the drill spindle is displaced, thereby
The chips are cut into short and long pieces every predetermined rotation of the drill spindle, and the chips can be intermittently discharged from the hole that is being drilled. therefore.

There is no longer a long chain of chips that are continuously discharged out of the hole, which deteriorates the discharge performance, and there is no longer a case where chips get stuck between the hole and the drilling tool. It is possible to reliably prevent a situation in which free machinability is impaired due to the increased cutting resistance, resulting in a decrease in drilling work efficiency, and furthermore, a situation in which the cutting blade is abnormally worn.

In particular, as shown in the above embodiment, the curvatures of three or more rolling elements are all changed, one recess into which the rolling elements fit is formed on each rolling race, and one If the spindle is configured to slide momentarily with each rotation, the length of the chips removed by the annular cutter with a relatively small cutting diameter will be extremely short, and the chips will be ejected from the hole. It is possible to prevent this from becoming difficult.

[Brief explanation of drawings]

The drawings show one embodiment of the drill device according to the present invention, and FIG. 1 is a longitudinal sectional view of the spindle and its surroundings showing the normal state of the drill spindle during cutting, and FIG. 2 is a rolling track of the thrust balls. FIG. 3 is a vertical cross-sectional view of the drill spindle and its surroundings showing the state of the drill spindle when cutting is interrupted, and FIG. 4 is the entire drill device. FIG. 5 is a perspective view showing another combination of the rolling track of the thrust ball and the recess of the thrust ring formed on the track, and FIG. 6 shows the main parts of another embodiment. FIG. 5...Drilling machine, 6...Casing, 9...Drilling knife. DESCRIPTION OF SYMBOLS 10... Drill spindle, 15... First thrust ring, 16... Second thrust ring, 17... Thrust ball (roller), 18... Ball accommodation hole, 2
゜...4 parts, LL, L2. L3...Rolling track, 30
...Ball accommodation hole, 31...First thrust ring,
32... Rolling raceway groove, 33... Second thrust ring, 34... Recessed portion. Patent applicant: Nitto Kohki Co., Ltd. Figure 2 Figure 3 Figure 5 Former Figure 6 1゜

Claims (1)

[Claims] A drill spindle having a drilling tool mounting portion at its tip is supported on a casing so as to be movable back and forth in the axial direction, and a pair of thrust rings are fixed to the drill spindle and the casing so as to face each other, and further, At least three rolling elements are interposed on opposing surfaces of the thrust ring so that their mutual relative positions are regulated and are rotatable at fixed positions of the thrust ring fixed to the casing,
A drill device in which a plurality of recesses are formed on the rolling track of the rolling elements, in which all the rolling elements are temporarily engaged at the same time.