JPH0520204B2 - - Google Patents

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 blade at its tip has a groove connected to the cutting blade on its outer periphery, and chips generated during drilling are discharged out of the hole along the groove. The chips discharged out of the hole in this way vary depending on the material to be drilled, the cutting speed, and the feed rate of the drilling tool, but usually they are discharged continuously 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 chips that are continuously ejected out of the hole become relatively long.
Due to its own weight and increased ejection resistance, the ejection performance of chips decreases, and the cutting material gets stuck between the hole and the drilling tool, and the increased cutting resistance impairs the free machinability of the drilling work. There was a problem that the efficiency decreased, and furthermore, the cutting blades were abnormally worn and the cutting blades became dull due to the 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 the 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 interferes with the drilling operation, but also
There is no guarantee that the chips that are continuously discharged in a spiral or undulating manner will reliably come into contact with the barrier member. It is also possible to use a gun drill that supplies high-pressure cutting oil through the inside of the drilling tool and uses the pressure to flush out the chips along with the cutting oil.
In that case, a dedicated machine tool and tool head are required, and it is not applicable to portable or relatively small drilling machines such as drilling machines.

[Problem that the invention seeks to solve]

If the above-mentioned barrier member is used as a simple means to forcibly cut the chips that are continuously discharged from the hole, it will not only hinder the drilling operation but also cause the chips to come into contact with the barrier member. The present invention fundamentally solves this problem by selectively controlling the length of chips according to the drilling conditions and discharging them from the hole. The aim is to provide a drilling device that can.

[Means for solving problems]

As a means for solving the above-mentioned problems, the present invention has provided that 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 able to reciprocate along the axial direction, and the drill spindle is A pair of thrust rings are fixed concentrically at a predetermined distance between the outer circumference and the inner circumference of the casing, and the space between the thrust rings is in contact with the opposing surfaces of the pair of thrust rings that face each other in the axial direction of the drill spindle. The main structure is a rotatably arranged rotor support ring that supports three or more rolling elements that can roll, and the center of gravity of the rotor support ring is the rotation center of the drill spindle. Three or more rolling elements are supported so that they can rotate on their own axis with their relative positions regulated, and all rolling elements are on the rolling track of the rolling elements on the thrust ring fixed to the drill spindle. an operating member having a plurality of concave portions recessed in the axial direction of the drill spindle with which the rollers engage temporarily and simultaneously, and further selectively locking the rotor support ring to suppress its rotation; A configuration consisting of the following is adopted.

[Effect]

In the drill device of the present invention, when the rotor support ring that supports the rolling elements that roll under the thrust direction load of the drill spindle is fixed to one thrust ring, each of the rolling elements rotates at a fixed position on one of the thrust rings and rolls into contact with the other thrust ring, and the rolling elements move into the respective recesses formed on the other thrust ring with each predetermined rotation of the drill spindle. When inserted, the drill spindle, which applies thrust forward force to the drilling tool, is slightly displaced in the axial direction in response to the depth of the recess, and cutting by the drilling tool is momentarily stopped. , thereby
Chips are cut into a predetermined length every predetermined rotation of the drill spindle and are discharged from the hole that is being drilled. When the rolling element support ring is in a free rotating state with respect to both thrust rings, each of the rolling elements supported by it rolls in rolling contact with both thrust rings, and the amount of rolling is: The stroke is half the rotation angle of the thrust ring that rotates integrally with the drill spindle, and the rotor support ring rotates at half the rotation speed of the drill spindle, and the drill at that time The number of displacements of the spindle in the direction opposite to the tip of the spindle relative to the number of revolutions of the spindle is half the number of displacements when the rotor support ring is fixed to one thrust ring that does not have a recess as described above. be done. In this way, chips are selectively cut into two different lengths and discharged according to two-step switching of the number of sliding displacements of the drill spindle relative to the number of revolutions of the drill spindle.

〔Example〕

As shown in FIG. 4, the drill apparatus of this embodiment has an electromagnetic adsorption base 2 fixed to a desired position of a workpiece 1 by electromagnetic adsorption on a drill stand 3.
A drilling machine 5 is supported on the side of the stand 3, which can move forward and backward with respect to the workpiece by rotating the lifting operation handle 4 and operating an automatic feed unit (not shown). .

As shown in FIG. 1, the drilling machine 5 has a built-in electric motor (not shown) in a casing 6, and its motor shaft 7.
The rotation is slowed down by two sets of helical gears 8A to 8D and transmitted to a drill spindle 10 having a removable drilling blade 9 such as an annular cutter at its tip.

The tip of the drill spindle 10 protrudes from a housing block 11 screwed onto the lower end of the casing 6.
Radial needle bearing 12 fitted and fixed in
The drill spindle 1 has a radial needle bearing 14 which pivotally supports the middle part of the drill spindle 10 and which is provided on the partition plate 13 of the casing 6.
The upper end of 0 is pivotally supported. On the drill spindle 10, the parts that can be contacted and supported by the pair of radial needle bearings 12 and 14 are:
By setting the bearing to be slightly longer than its axial length, the drill spindle 10 can be slightly reciprocated in its axial direction.

15 is the radial needle bearing 12
The first thrust ring is rotatably fixed to the drill spindle 10 located above, and has a rolling track 17 on its outer circumferential surface that can receive a thrust load that curves upward and is equal to the curvature of the thrust ball 16. . In the outer circumferential direction of the ring 15,
The second thrust ring 18, whose inner peripheral surface faces the rolling raceway 17 with a predetermined gap, is attached to the casing 6.
A rolling track 19 is formed on the inner peripheral surface of the ring 18 to receive a downwardly curved thrust load equal to the curvature of the thrust ball 16.

Reference numeral 20 denotes a ball housing hole into which the three thrust balls 16 as rolling elements that can roll on the rolling raceways 17 and 19 are individually and concentrically fitted while being rotatable and regulating their relative positions. 22, a part of the surface of the thrust ball 16 protrudes from the inner and outer peripheral surfaces of the ball support ring 20, and the rolling raceway 17 is
and 19, in a space in which the thrust rings 15 and 18 face each other. The ball accommodation holes 22 are formed at intervals of 120° with respect to the axis of the ball support ring 20. The first thrust ring 15 receives the elastic force of a compression coil spring 26 interposed between the upper end surface of the radial needle bearing 12 via a spacer 25, and is integrally moved with the drill spindle 10 from the workpiece. It is urged in the direction of separation. Therefore, the first thrust ring 15 supports the drill spindle 10, which is integrated with the ring 15, in its thrust direction by elastically pressing the thrust ball 16 against the second thrust ring 18.

On the rolling track 17 of the first thrust ring 15, three spherical recesses 27, into which the thrust balls 16 can be engaged and detached, are formed at intervals of 120 degrees with respect to the axis thereof, all at the same depth. When the three thrust balls 16 fit into the recess 27 at the same time, the drill spindle 10 integrated with the first thrust ring 15, which is resiliently biased in the direction opposite to the tip by the compression coil spring 26, simultaneously , is displaced backward by a distance corresponding to the depth dimension of the recess 27 (displaced upward in FIG. 1). The recess 27
The depth is set, for example, to be approximately equal to the maximum allowable thickness of 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.

The ball support ring 20 has an outer peripheral edge at its lower end protruding downward from the opposing space of the thrust rings 15 and 18, and a plurality of approximately semicircular notches 30 are formed on the protruding outer peripheral edge. , an operation knob 31 that fits into the notch 30 and locks the ball support ring 20 at its tip is attached to the casing 6.
It is inserted from the outside into the elongated hole 33 via the disc spring 32, and its intermediate portion is screwed into a nut 34 that can slide on the inner surface of the casing 6. The ball support ring 20 is connected to the second thrust ring 18 by the operation knob 31 being fitted and locked into the notch 30.
The operation knob 3 is in a fixed state, and the operation knob 3
1 is removed from the notch 30, so that it assumes a free rotation state.

The ball support ring 20 is attached to the second thrust ring 1
8, the thrust ball 16 accommodated and supported by the ball support ring 20 only rotates at a fixed position on the second thrust ring 18, so the first thrust ring integrated with the drill spindle 10 The drill spindle 10 is inserted into the recess 27 at a rate of three times per one rotation of the drill spindle 15, and the drill spindle 10, which is urged in the direction opposite to the tip end by the compression coil spring 26, is displaced in the axial direction. Therefore, in such a state, the drill spindle 10, which applies a downward thrust to the drilling blade 9, is displaced in the anti-tip direction three times per rotation, depending on the depth of the recess 27. Cutting by the punching blade 9 is momentarily stopped, thereby controlling the length of chips to a cutting length determined by approximately 1/3 rotation of the punching blade 9.

When the first thrust ring 15 is rotated integrally with the drill spindle 10 with the ball support ring 20 in a free state, the outer peripheral surface side of the thrust ball 16 rolls into contact with the second thrust ring 18;
The three thrust balls 16 roll and move relative to the first thrust ring 15 with which the inner circumference side of the thrust balls 16 rolls into contact, and the ball support ring 20 rotates following this. Therefore, the relative rolling movement distance of the first thrust ring 15 with respect to the thrust ball 16 is made equal to the rolling movement distance of the thrust ball 16 with respect to the second thrust ring 18, so that the first thrust ring 15 is rotated. and thrust ball 16
The second thrust ring 18 has a stroke that is half the rotation angle of the first thrust ring 15.
Move by rolling on top. Therefore, the first thrust ring 15 rotates together with the drill spindle 10.
The three thrust balls 16 fit into each recess 27 three times for every two rotations of the drill spindle 1.
0 in the axial direction. Therefore, in such a state, the drill spindle 10 is
It displaces in the anti-tip direction according to the depth of the recess 27 at a rate of 3 rotations to momentarily stop cutting by the punching blade 9, thereby reducing the length of the chips. The cutting length is controlled by approximately 2/3 rotation of the

The drilling blade 9 is an annular cutter, and a set screw 40 is attached to the cutter arbor 39 of the drill spindle 10.
The pilot pin 41 is removably fixed on the drilling tool 9 on the axis of the drilling tool 9.
It is inserted so that it can freely protrude and retract from the lower end surface. When the drilling tool 9 is attached to the drill spindle 10,
The head of the pilot pin 41 is connected to the press piece 4 which receives the elastic force of a compression coil spring 42 housed in the cutter arbor 39 of the drill spindle 10.
In this state, the tip of the pilot pin 41 protrudes from the lower end surface of the drilling tool 9 and functions as the center of the drilling tool 9.
The cutter arbor 39 idles in contact with the surface of the workpiece, more precisely, the surface of the core, according to the feed of the cutter arbor 39.
When the drilling machine 5 is moved upward and the drilling machine 5 is returned to the upward position after completing the drilling process, the cut piece is pushed out from inside the drilling blade 9 by the elastic force of the compression coil spring 42.

Next, the operation of the above drill device will be explained.

The first thrust ring 15 has three thrust balls 16 accommodated and supported by a ball support ring 20.
By resiliently pressing the second thrust ring 18 toward the second thrust ring 18, the drill spindle 10, which is integrated with the second thrust ring 15, is supported in its thrust direction.

For example, the cutting diameter of the punching blade 9 is relatively small;
Alternatively, if the drilling depth is relatively deep, position the operating knob 31 at the lower end of the elongated hole 33 as shown in FIG. The nut 34 is tightened and fixed to the inner surface of the casing 6 by turning the operation knob 31 so as to maintain the state. When the drill spindle 10 is driven to rotate in this state, the thrust balls 16 accommodated and supported by the ball support ring 20 are rotated between the rolling track 19 of the second thrust ring 18 fixed to the casing 6 and the drill spindle 10.
The rolling tracks 16 of the second thrust ring 18 rotate together with the ball support ring 20 for every two rotations of the drill spindle 10, while rolling in contact with the rolling tracks 16 of the first thrust ring 15 rotating integrally with the ball support ring 20.
During the movement, the three thrust balls 16 enter the three recesses 27 provided on the rolling track L17, and the three thrust balls 16 rotate once on the drill spindle 10 for two revolutions.
When inserted simultaneously, the drill spindle 10 and the first thrust ring 15 are integral with each other and are subjected to the elastic force of the compression coil spring 26.
moves in the axial direction by a distance corresponding to the depth dimension of the recess 27, and is displaced upward in FIG.
The state shown in FIG. 1 changes to the state shown in FIG. 2. Therefore, during drilling, the drill spindle 10, which applies a feeding force along the thrust direction to the drilling blade 9 via the rotary operation handle 4 and an automatic feeding unit (not shown), adjusts the depth of the recess 27. When the tip is displaced in the opposite direction in response to Since this is approximately the same as the maximum allowable thickness of chips, the cutting by the punching tool 9 stops instantaneously at the same time, so that the chips have a cutting length determined by approximately 2/3 rotation of the punching tool 9. It is controlled to be intermittently discharged from the hole that is being drilled.

When the cutting diameter of the drilling blade 9 is relatively larger or the drilling depth is relatively shallow than in the above case, the third
By positioning the operation knob 31 at the upper end of the long hole 33 as shown in the figure, the linear end of the operation knob 31 is fitted into the notch 30 of the ball support ring 20, and the ball support ring 20 is locked and fixed. The nut 34 is tightened and fixed to the inner surface of the casing 6 by turning the operation knob 31 so as to maintain this state. In this state,
When the ball support ring 20 is fixed to the casing 6, in other words, fixed to the second thrust ring 18, and the drill spindle 10 is driven to rotate, the three thrusters accommodated and supported by the ball support ring 20 are Each of the balls 21 rotates at a fixed position on the second thrust ring 18 and comes into rolling contact with the first thrust ring 15, and rolls on the rolling track 17 of the first thrust ring 15 three times per rotation of the drill spindle. Recessed part 2 provided on top
7, the drill spindle 10 and the first thrust ring 15, which are integral with each other, are displaced in the axial direction by a distance corresponding to the depth dimension of the recess 27, from the state shown in FIG. 3 to the state shown in FIG. changes to the state of Therefore, in such a case, the chips are controlled to a cutting length determined by approximately 1/3 rotation of the drilling blade 9,
It is intermittently discharged from the hole that is being drilled.

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

For example, in the above embodiment, the number of displacements of the drilling blade 9 in the direction opposite to the tip end can be selectively switched 3 or 6 times per two rotations of the drill spindle 10. In the case where a cutter is applied, six recesses 27 are formed at 60° intervals in the rolling raceway 17 of the above embodiment,
It is also possible to configure the drill spindle 10 to selectively move backward 3 or 6 times per rotation of the drill spindle 10, and the number of thrust balls and recesses can be adjusted according to various drilling conditions. By setting and combining them appropriately, while keeping the ratio of mutually switchable backward displacement times constant,
The ratio of the maximum number of backward displacements of the drill spindle to the number of revolutions of the drill spindle can be variously changed to 3/2 or more.

Further, the rolling elements interposed between the pair of thrust rings are not limited to thrust balls, but can be changed to tapered rollers, and the drilling tool attached to the tip of the drill spindle is not limited to an annular cutter,
It may also be a twist drill.

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

〔Effect of the invention〕

The drill device of the present invention can cut chips into short and long pieces every predetermined rotation of the drill spindle, and can intermittently discharge the chips from a hole that is being drilled. Therefore, the chips discharged outside the hole do not continue for a long time and the discharge performance deteriorates, and the chips do not get stuck between the hole and the drilling tool, unlike before. It is possible to reliably prevent a situation in which free machinability is impaired and drilling work efficiency is reduced, or furthermore, the cutting blade is abnormally worn.

Moreover, when the rolling element support ring is free with respect to both thrust rings, the rolling element supporting ring rotates relative to the rotation speed of the drill spindle at half the rotation speed of the drill spindle at that time. The number of displacements of the spindle in the direction opposite to the tip is theoretically half the number of displacements when the rotor support ring is fixed to a thrust ring without a recess, and thereby the drill spindle is The number of displacements of the spindle relative to the rotational speed can be set in two stages, and chips can be selectively discharged at two different lengths depending on the drilling conditions. Selection of the chip length according to the drilling conditions can be achieved by locking and disengaging the rotor support ring with the operating member, and by disassembling the drill device or replacing parts. Since there is no need to do this, the chip length can be easily optimized depending on the drilling conditions.

[Brief explanation of the drawing]

The drawings show one embodiment of the drill device according to the present invention, and FIG. 1 shows the drill spindle during cutting with the ball support ring capable of displacing the spindle three times for every two revolutions of the drill spindle. Fig. 2 is a vertical cross-sectional view showing the normal state of the surroundings, and shows the state of the surroundings of the drill spindle when cutting is interrupted in the positioning state of the ball support ring that can move the drill spindle backward three times for every two rotations of the drill spindle. FIG. 3 is a longitudinal sectional view showing the normal state around the drill spindle during cutting in a positioning state of a ball support ring that can move the spindle backward three times per rotation of the drill spindle; FIG. 4 is a longitudinal sectional view showing the state around the drill spindle when cutting is interrupted in a positioning state of a ball support ring that can move the spindle backward three times per revolution of the drill spindle;
FIG. 5 is a perspective view showing the relationship between the rolling trajectory of the thrust ball regulated by the ball support ring and the recess of the thrust ring formed on the trajectory;
FIG. 6 is a schematic front view showing the entire drill device. 5... Drilling machine, 6... Casing, 9... Drilling blade, 10... Drill spindle, 15... First
Thrust ring, 16... Thrust ball (roller), 17... Rolling raceway, 18... Second thrust ring, 19... Rolling track, 20... Ball support ring (roller support ring), 22...ball accommodation hole, 27...recess, 30...notch, 31...
operation knob.

Claims (1)

[Scope of Claims] 1. A drill spindle, which is equipped with 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 holes are provided on the outer circumference of the drill spindle and the inner circumference of the casing. Thrust rings are fixed concentrically at a predetermined interval, and between the thrust rings are three or more thrust rings that can roll in contact with the opposing surfaces of a pair of thrust rings that face each other in the axial direction of the drill spindle. A drill device in which a rolling element supporting ring supporting a rolling element is rotatably arranged, and the rolling element supporting ring has three or more rolling elements so that the center of gravity is the rotation center of the drill spindle. The rollers are supported so as to be able to rotate on their own axis while regulating their relative positions, and all the rolling elements are temporarily and simultaneously on the rolling track of the rolling elements on one of the thrust rings fixed to the drill spindle. A plurality of engaging recesses are formed in the axial direction of the drill spindle, and an operating member is further provided to selectively lock the rotor support ring and suppress its rotation.
drilling equipment.