JP2580678Y2 - Drill equipment - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drill device having improved chip discharge and cutting performance by a drilling cutter.

[0002]

2. Description of the Related Art A drilling tool such as an annular cutter or a twist drill having a cutting blade at its tip is provided with a groove connected to the cutting blade on the outer periphery, and chips generated by the drilling operation are discharged out of the hole along the groove. I do. Chips discharged in this way outside the hole vary depending on the material to be pierced, the cutting speed, the feed speed of the drilling blade, and the like, but are usually continuously discharged with a predetermined length. By the way, when the thrust is given to the drilling cutter with the feed rate of the drill spindle kept almost constant, the length of the chips continuously discharged out of the hole continues to be relatively long, and the cutting weight increases due to its own weight and the discharge resistance. The debris discharge performance is reduced, the chips are clogged between the hole and the drilling tool, and the increased cutting resistance impairs the free-cutting performance and reduces the drilling work efficiency. And the frictional heat causes the cutting edge to become dull. In this regard, the inventor of the present application has filed an earlier application (Japanese Patent Application No. 61-210603 (Japanese Patent Application No. 5-2020).
3)), a drill spindle provided with a mounting portion for a drilling tool at a tip portion is supported on a casing so as to be able to reciprocate in the axial direction, and the drill spindle and the casing are opposed to each other in the axial direction of the drill spindle. Then, a pair of thrust rings are fixed, and further, at least three rolling elements are arranged on the opposing surface of the thrust rings so as to be able to roll with their relative positions regulated, and the rolling tracks of the rolling elements are arranged. Above, a drill device is proposed in which a plurality of recesses are formed in which all the rolling elements temporarily and simultaneously engage. According to this, when the rolling elements rolling under the load in the thrust direction of the drill spindle are temporarily and simultaneously fitted in the respective recesses at every predetermined rotation of the same spindle, the advance output along the thrust direction is then performed. The drill spindle acting on the drilling cutter is slightly displaced in the axial direction in response to the depth of the recess, so that the cutting by the drilling cutter is instantaneously stopped, so that every predetermined rotation of the drill spindle The chips can be cut into predetermined lengths and discharged from the holes.

[0003]

As a result of further study of such a drilling device, the inventor of the present invention tried to cut chips by forcibly retracting the drill spindle by a small distance several times per rotation of the drill spindle. It has been found that there is still room for improvement in more effective chip discharge, processing accuracy, and improvement in the durability of the blade.
That is, the prior art for simply cutting chips has not considered the efficient absorption of heat generated by the cutting force by the chips.

An object of the present invention is to not only cut the chips by forcibly retracting the drill spindle by a minute distance intermittently at every predetermined rotation of the drill spindle, but also to cut off the heat generated by the cutting resistance with the chips. An object of the present invention is to provide a drill device that can be efficiently absorbed, thereby contributing to improvement in machining accuracy and durability of a cutting tool.

[0005]

According to the invention of the present application, a drill spindle provided with a mounting portion for a drilling tool at its tip is axially supported on a casing so as to be able to reciprocate in the axial direction, and the drill spindle and the casing are provided with the same. Fix a pair of thrust rings facing each other in the axial direction of the drill spindle,
On the opposing surface of the thrust ring, at least three rolling elements are arranged so as to be able to roll while regulating the relative position, and further, all the rolling elements are temporarily on the rolling track of the rolling elements. And simultaneously forming a plurality of first recesses,
A large number of second concave portions having a dimension shallower than the concave portions are formed with an interval smaller than the interval between the first concave portions.

[0006]

When a rolling element which rolls by receiving a load in a thrust direction of a drill spindle temporarily and simultaneously fits into each of the first recesses at every predetermined rotation of the spindle, at that time,
The drill spindle acting on the drilling tool with the advance output along the thrust direction is slightly displaced in the axial direction in response to the depth of the first concave portion, thereby instantaneously stopping the cutting by the drilling blade, Thereby, the chip is cut into a predetermined length every predetermined rotation of the drill spindle and discharged from the hole.
Such an operation is performed intermittently at every predetermined rotation of the drill spindle, during which the rolling element rolls while traversing over a large number of second recesses on the rolling track, causing micro-vibration, in other words, to the drill spindle. In this case, small vertical movements are constantly given.
Such a steady fine vibration or a slight vertical fine movement changes the thickness of the chip in accordance with the vibration cycle when cutting is performed at the tip of a knife having a rake angle.
As shown in (B), the chip is finely curled at the part where the part is thinned. The finely curled chips are discharged while contacting the rake face of the blade by its own weight.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 4, a drill device according to this embodiment has an electromagnetic attraction base 2 fixed at a desired position of a workpiece 1 by electromagnetic attraction at a lower portion of a drill stand 3 and the same stand. On the side of 3, a drilling machine 5 that can move forward and backward with respect to the workpiece 1 by the rotation operation of the lifting operation handle 4 and the operation of an automatic feed unit (not shown) is supported. The drilling machine 5 has an electric motor (not shown) built in a casing 6 as shown in FIG. 1, and the rotation of the motor shaft 7 is reduced by two sets of bevel gears 8A to 8D, and a drilling machine such as an annular cutter is provided at the tip. Drill spindle 1 with detachable blade 9
Transmit to 0.

[0008] The drill spindle 10 is a casing 6
The distal end of the housing block 11 is screwed and fixed to the lower end of the housing block 11, and the intermediate portion of the drill spindle 10 is supported by the radial needle bearing 12 fitted and fixed in the housing block 11, The upper end of the drill spindle 10 is pivotally supported by the provided radial needle bearing 14. 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 slightly longer than the axial length of the bearing, so that the drill spindle 10 is slightly moved in the axial direction. Can be reciprocated.

Reference numeral 15 denotes a flange-shaped first thrust ring fixed to the outer peripheral portion of the drill spindle 10 located above the radial needle bearing 12 so as to be integrally rotatable therewith. The disk-shaped second thrust ring 1 whose center hole is loosely fitted to the drill spindle 10 is opposed to the second thrust ring.
6 is fitted and fixed to the casing 6.

Reference numeral 20 denotes a ball support ring having a ball receiving hole 22 in which thrust balls 21, 21 and 21 as three rolling elements are rotatable, and their relative positions are regulated and individually fitted. (Roller element support ring) is rotatably loosely fitted on the outer peripheral portion of the drill spindle 10 located in the space where the thrust rings 15 and 16 are opposed to each other. As shown in FIG. 2, the ball receiving hole 22 is provided with the drill spindle 1 so that the rolling trajectory of the thrust ball 21 is different.
Different distances D1, D1 from the center C2 which coincides with the 0 axis.
D2 and D3 (where D1>D2> D3), and
Relative angular positions θ1, θ2, θ relative to the same center C2
Three are formed so as to take three. Such a ball accommodation hole 22
A part of the surface of the thrust ball 21 protruding from the upper and lower surfaces of the ball support ring 20 is contacted with the opposing surfaces of the thrust rings 15 and 16 so that the thrust ball 21 can roll.

The first thrust ring 15 includes a spacer 25
, The spring force of the compression coil spring 26 interposed between the radial needle bearing 12 and the upper end surface of the radial needle bearing 12, and urges the drill spindle 10 integrally with the drill spindle 10 in a direction away from the workpiece 1. Have been. Therefore, the first thrust ring 15 is connected to the thrust ball 2.
1 is resiliently pressed against the second thrust ring 16, thereby supporting the drill spindle 10 integrated with the ring 15 in the thrust direction. The thrust rings 15 and 16 are provided with three thrust balls 21,
Are supported at three points in a state of being resiliently pressed by the ball receiving holes 21 and 21.
1, θ2, θ3 and the respective distances D1, D2, D3 with respect to the axis of the drill spindle 10 are set such that the forces acting on the three support points are balanced at the axis of the drill spindle 10, and Support ring 20
Center C2 coincides with its center of gravity. As a result, the pair of thrust rings 15, 16 and the ball support ring 2
0 and the thrust balls 21 support the drill spindle 10 in a stable state in the thrust direction irrespective of the number of rotations without applying eccentric rotation or tilting force. Prevent wear.

The upper end surface of the first thrust ring 15 is provided on the respective rolling trajectories L1, L2, L3 of the thrust balls 21 which are accommodated and rolled in the ball accommodation holes 22 so that the respective ball accommodation holes 22 are disposed on each other. The spherical recesses 27 having the same relationship as the relative angular positions θ1, θ2, and θ3 with respect to the center C1 of the thrust ring 15 are all formed one by one at the same depth. Therefore, the three thrust balls 21 are
Are inserted simultaneously, the first thrust ring 15 elastically biased in the direction opposite to the distal end by the compression coil spring 26.
The drill spindle 10 is retracted by a distance corresponding to the depth of the recess 27 (displaced upward in FIG. 1). The depth of the recess 27 is set, for example, substantially equal to the maximum allowable thickness dimension of the chip shaved by the drilling tool 9. The maximum allowable thickness of the chip is determined in relation to the maximum rotation speed of the drill spindle 10 and the maximum allowable feed speed of the drilling machine 5 which the drilling device has as its maximum drilling ability, and furthermore, the material of the workpiece 1 and the like. Is done.

Further, in each of the rolling orbits L1 to L3 on the first thrust ring 15, a groove 23 (an example of a second concave portion) having a dimension shallower than the concave portion 27 is formed. A large number are formed radially at small intervals.
For example, with respect to the depth of the recess 27, the groove 23 is formed so that the feed amount of one blade of the drilling tool 9 by an automatic feed unit (not shown) of the drill device is slightly smaller than the feed amount per rotation of the drill spindle. Is set.

The outer peripheral edge of the upper end surface of the first thrust ring 15 and the outer peripheral edge of the lower end surface of the second thrust ring 16 are
The projections 30 and 31 are formed radially, and concave grooves 32 and 33 associated with the respective projections 30 and 31 are formed on the upper and lower surface outer peripheral edges of the ball support ring 20.
At a position close to the thrust rings 15 and 16, a guide tip 34 having a U-shaped cross section for supporting the ball support ring 20 slidably in the axial direction in a space facing the rings 15 and 16.
And the guide tip 34 is attached to the ball support ring 20.
The operation knob 3 is inserted through a long hole 36 formed from the outer wall of the casing 6 with a disc spring 35 interposed in the axial direction of the casing 3.
7 is fixed with a screw to the tip. This operation knob 37
Is moved along the long hole 36, so that the ball support ring 20 is engaged with the second thrust ring 16, which is achieved by engaging the projection 31 with the groove 33, and the projection 30 is engaged with the groove 32. The locking state with the first thrust ring 15 and the non-locking state with both thrust rings 15 and 16 can be selectively adopted.

When the ball support ring 20 is locked and fixed to the second thrust ring 16, the thrust ball 21 accommodated and supported by the ball support ring 20 only rotates at a fixed position on the second thrust ring 16. The compression coil spring 2 is engaged with the recess 27 at a rate of once per rotation of the drill spindle 10 and the first thrust ring 15.
6 displaces the drill spindle 10 which has been repelled in the direction toward the tip end in the axial direction. Therefore, in such a state, the drill spindle 10 that applies a downward thrust to the drilling tool 9 is displaced in the direction opposite to the tip end once per rotation according to the depth of the concave portion 27, and the cutting by the drilling tool 9 is performed. Is stopped instantaneously, thereby controlling the length of the chip to a cutting length determined by substantially one rotation of the drilling tool 9.

The thrust ring 1 is connected to the ball support ring 20.
When the first thrust ring 15 is rotated integrally with the drill spindle 10 in a non-locking state with respect to the thrust balls 5 and 16, the second thrust ring 16 in which the upper surface of the thrust ball 21 is in rolling contact with the thrust ball 21, The three thrust balls 21 relatively roll and move between the first thrust ring 15 whose lower surface is in rolling contact, and the ball support ring 20 rotates following the thrust balls 21. Thus, since the relative rolling movement distance of the first thrust ring 15 with respect to the thrust ball 21 is made equal to the rolling movement distance of the thrust ball 21 with respect to the second thrust ring 16, the first thrust ring 15 is rotated. And the thrust ball 21 has a half stroke with respect to the rotation angle of the first thrust ring 15,
6. Roll on top. Therefore, drill spindle 1
Three thrust balls 21 are provided in each of the recesses 2 at a rate of once every two rotations of the first thrust ring 15 that rotates integrally with the first thrust ring 15.
7, the drill spindle 10 is slidably displaced in the axial direction. Therefore, in such a state,
The drill spindle 10 is displaced in the anti-tip direction according to the depth of the concave portion 27 at a rate of once every two rotations, thereby instantaneously stopping the cutting by the drilling tool 9, thereby reducing the length of the chip. Is controlled to a cutting length determined by substantially two rotations of the drilling blade 9.

The ball support ring 20 is connected to the first thrust ring 1 while the thrust ball 21 is engaged with the recess 27.
5, the thrust ball 21 accommodated and supported by the ball support ring 20 always keeps the state of being fitted into the concave portion 27 and rolls with the second thrust ring 16 while rotating at a fixed position of the first thrust ring 15. Since it only makes contact, the drill spindle 10 integral with the first thrust ring 15 is not displaced in the axial direction at all during its rotation, and the length of the chips is not specifically controlled.

The drilling tool 9 is an annular cutter, which is detachably fixed to a cutter arbor 39 of the drill spindle 10 by a fixing screw 40. A pilot pin 41 is provided on the axis of the drilling tool 9 with a pilot pin 41. Is inserted from the lower end surface so as to be freely retractable. When the drilling blade 9 is mounted on the drill spindle 10, the head of the pilot pin 41 is pressed by the tip of the press piece 43 which receives the elastic force of the 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 projects from the lower end surface of the drilling tool 9 and functions as a center of the drilling tool 9, and during drilling, the surface of the workpiece 1 according to the feed of the drill spindle 10, Precisely, the cutter idles while being in contact with the surface of the core, and the cutter arbor 39 is displaced upward, and when the drilling machine 5 is returned to the elevated position after the completion of the drilling, the cut piece is rejected by the elastic force of the compression coil spring 42 to cut the drilling blade 9. It is pushed out from the inside.

Next, the operation of the above embodiment will be described. The first thrust ring 15 resiliently presses the three thrust balls 21 housed and supported by the ball support ring 20 toward the second thrust ring 16 to thereby form a drill spindle 10 integrated with the ring 15. Is supported in the thrust direction. For example, when the depth of drilling by the drilling blade 9 is relatively deep, that is, when the workpiece is relatively thick, the operation knob 37 is positioned at the center of the elongated hole 36 as shown in FIG. Then, the ball support ring 20 is unlocked to the thrust rings 15 and 16, and the operation knob 37 is turned so that the guide tip 34 is tightly fixed to the inner surface of the casing 6 so as to maintain the state. When the drill spindle 10 is driven to rotate in this state, the thrust ball 21 housed and supported by the ball support ring 20 is moved to the second thrust ring 16 fixed to the casing 6,
One rotation on the second thrust ring 16 together with the ball support ring 20 for two rotations of the drill spindle 10 while rolling contact with the respective opposing surfaces of the first thrust ring 15 rotating integrally with the drill spindle 10. When the three thrust balls 21 are simultaneously fitted into the recesses 27 provided on the respective rolling orbits L1, L2, L3 at a rate of once every two rotations of the drill spindle 10, the compression coil spring The mutually integral drill spindle 10 and the first thrust ring 15 receiving the resilience of 26 move in the direction opposite to the distal end by a distance corresponding to the depth dimension of the recess 27, and are displaced upward in FIG. Then, the state of FIG. 1 changes to the state of FIG. Accordingly, during drilling, the drill spindle 10 that is applying a downward feed force in the thrust direction to the drilling blade 9 via the rotary operation handle 4 or an automatic feed unit (not shown) increases the depth of the recess 27. , The movement corresponds to substantially stopping the feed of the drilling tool 9 in the cutting direction, and the displacement amount is the maximum allowable thickness of the chip shaved by the drilling tool 9. At the same time, the cutting by the drilling tool 9 stops instantaneously, whereby the chip is controlled to a cutting length determined by substantially two rotations of the drilling tool 9, and the chip is being cut. It will be intermittently discharged from the hole.

The above operation is intermittently performed only once every two rotations of the drill spindle 10. During this time, the rolling element 21 rolls while traversing over a large number of grooves 23 of L1 to L3 on the rolling track. As shown in FIG. 5, the drill spindle 10 is steadily given a slight vibration, in other words, a slight vertical movement. Such steady micro-vibration or gradual vertical micro-movement changes the thickness of the chip in accordance with the vibration cycle when cutting is performed with the cutting edge of the cutting tool 9 having a rake angle. The chip is finely curled around the partially thinned area as shown. The finely curled chips are smoothly discharged while contacting the rake face of the blade 9 by its own weight. Further, since the contact area between the chip and the cutting tool 9 increases, the heat of the cutting tool can be easily transmitted to the cutting chip due to the cutting resistance, and the effect of suppressing a rise in the temperature of the cutting edge can be expected, which improves the durability of the cutting tool. And contribute to the improvement of cutting accuracy. If the groove 23 is not formed, the chip is supported by its own rigidity until the chip is separated by the action of the recess 27 as shown in FIG. As a result, the contact portion with the rake face of the cutting tool is often limited to the cutting edge portion.

In the case where the cutting diameter of the drilling blade 9 is relatively large or the depth of the drilling is relatively shallower than in the above case, the operation knob 37 is positioned at the upper end of the long hole 36 so that the projection 3 is formed.
1 is connected to the groove 33, and the ball support ring 20 is connected to the second groove.
The guide tip 34 is fixedly fastened to the inner surface of the casing 6 by turning the operation knob 37 so as to lock and fix the thrust ring 16 and maintain the state. In this state, the ball support ring 20 assumes the locked state with the second thrust ring 16, and when the drill spindle 10 is driven to rotate, the three thrust balls 21 accommodated and supported by the ball support ring 20 are respectively in the third state. It rotates at a fixed position on the second thrust ring 16 and comes into rolling contact with the first thrust ring 15, and on the rolling trajectories L1, L2, L3 of the first thrust ring 15 at a rate of once per rotation of the drill spindle. At the same time, the drill spindle 10 and the first thrust ring 15 integrated with each other are displaced in a direction opposite to the distal end by a distance corresponding to the depth dimension of the concave portion 27. Therefore, in this case, the chips are intermittently discharged from the hole being drilled while being controlled to a cutting length determined by substantially one rotation of the drilling blade 9. At this time, as in the above, the rolling element 21 has a large number of grooves 2 of L1 to L3 on the rolling track.
Drill spindle 1
Since small vertical movements are constantly given to 0, such steady fine vibrations or small vertical movements change the thickness of the chips in accordance with the vibration cycle and cause the chips to curl finely. Debris is easily discharged from the cutting hole, and the contact area with the blade increases.

In the case of drilling a workpiece as thin as it is not necessary to cut chips, or in a workpiece such as cast iron, in which the chips are hardly continuous due to its own properties, drilling is performed. In such a case, or when the reliability of the chip breaking function is low but the drilling tool itself has a chip break function, the operation knob 37 is positioned at the lower end of the elongated hole 36 so that the projection 30 is engaged with the groove 32. While stopping, all the thrust balls 21 are fitted into the concave portions 27,
The ball support ring 20 is locked and fixed to the first thrust ring 15, and the operation tip 37 is turned so that the guide tip 34 is tightly fixed to the inner surface of the casing 6 so as to maintain the state. In this state, the thrust ball 21 housed and supported by the ball support ring 20 rotates integrally with the rotation of the first thrust ring 15 while constantly maintaining the state of being fitted into the concave portion 27, and Since the first thrust ring 15 and the drill spindle 10 are rolled along the lower surface of the drill 16, the first thrust ring 15 and the drill spindle 10 are not displaced in the axial direction at all during the rotation thereof, and the chip is not actively cut.

Although the present invention has been described in detail based on the embodiments, the present invention is not limited to the above-described embodiments, and can be variously modified without departing from the gist thereof. For example, in the above embodiment, the number of displacements of the drilling tool 9 is selectively switched at a rate of once or twice per two rotations of the drill spindle 10, but an annular cutter having a relatively large cutting diameter is applied. In this case, two sets of recesses 27 into which three thrust balls 21 can be simultaneously fitted are formed on the rolling orbits L1, L2, and L3 of the above-described embodiment, and each set of recesses 27 is formed for every rotation of the drill spindle 10. The spindle 10 is configured to be selectively displaced once or twice, or a common rolling trajectory of three thrust balls can be used to simultaneously fit three thrust balls on the trajectory. A set of recesses can be formed to selectively displace the drill spindle six or three times every two revolutions of the drill spindle. Thrust balls, rolling Orbit, The ratio of the maximum number of displacements of the drill spindle to the number of revolutions of the drill spindle can be varied to more than 1/2 while maintaining the ratio of the number of displacements that can be switched to each other constant by appropriately setting and combining the number of recesses and recesses. Can be changed. Further, the rolling element may be accommodated and held in one thrust ring. Further, the rolling elements interposed between the pair of thrust rings are not limited to thrust balls,
You may change to a tapered roller. Also, the drilling tool attached to the tip of the drill spindle is not limited to an annular cutter,
It may be a twist drill. In the above embodiment, the case where the present invention is applied to a drill device having a portable electromagnetic suction base has been described, but the present invention is also applicable to a small drilling machine and an electric drill.

[0024]

The effects obtained by the invention disclosed in the present application will be briefly described as follows. In other words, the rolling element is inserted into the first concave portion to slightly retreat the drill spindle, thereby instantaneously stopping the cutting by the drilling cutter and cutting the chips. Chips can be cut to a predetermined length and ejected from the cutting hole, and the rolling element rolls while traversing over a large number of second recesses on the rolling track, and finely moves to the drill spindle. Since the vibration, in other words, the fine vertical movement is constantly applied, the fine vibration or the vertical fine movement changes the thickness of the chip in accordance with the vibration cycle and finely curls the chip. When the chips are finely curled, they can be smoothly discharged along the rake face of the blade, and the contact area between the chips and the blade increases, so that the cutting resistance makes it easier to transfer the heat of the blade to the chips. An effect of suppressing a rise in the temperature of the cutting edge can be expected, which contributes to an improvement in durability of the cutting tool and an improvement in cutting accuracy.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of a drill device according to the present invention in a cutting state.

FIG. 2 is a perspective view showing a relationship between a rolling trajectory of a thrust ball and concave portions and grooves formed on the trajectory.

FIG. 3 is a longitudinal sectional view showing the drill device of FIG. 1 in a state where cutting is interrupted.

FIG. 4 is a schematic front view showing the entire drill device.

FIG. 5 is an explanatory diagram of a cross-sectional shape of a concave portion and a groove and a band vibration waveform.

FIG. 6 is an explanatory view conceptually showing the state of chips in a case where only a concave portion is formed and in a case where a concave portion and a groove are formed.

[Description of Signs] 9 Drilling Blade 10 Drill Spindle 15 First Thrust Ring 16 Second Thrust Ring 17 Thrust Ball (Roller) 18 Ball Housing Hole 23 Groove (Second Depression) 27 Depression (First Depression) L1, L2 , L3 rolling orbit

Claims (1)

(57) [Scope of request for utility model registration] 1. A drill spindle provided with a mounting portion for a drilling tool at a distal end thereof is supported on a casing so as to be reciprocally movable in the axial direction, and is opposed to the drill spindle and the casing in the axial direction of the drill spindle. And a pair of thrust rings are fixed to each other, and at least three rolling elements are disposed on opposing surfaces of the thrust rings so as to be capable of rolling while regulating their relative positions. A plurality of first recesses in which all the rolling elements are engaged temporarily and simultaneously are formed, and a second recess having a dimension shallower than the first recess is formed by a distance between the first recesses. Drilling device formed by forming a large number with small intervals.