JP3088994B2 - Centering device for shaft-like objects having a cutting edge - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a centering device for aligning the axial center of a shaft such as a drill for drilling with a center line of a strain measuring device or the like, and particularly to a drill for drilling concrete or tile. The present invention relates to a centering device for a shaft-like object having a cutting edge capable of accurately aligning a drill having a cutting edge at its tip.

[0002]

2. Description of the Related Art FIG. 3 is a partially enlarged view showing a conventional centering device for a shaft-like object. The centering device 1 shown in FIG. 3 is mounted on an axial strain measuring device that measures the strain in the short axis (radius) direction of a shaft-like object such as a concrete drill.

[0003] The centering device 1 comprises a chuck 2 on the left end in the figure and a receiving portion 3 on the right end. The chuck 2 has a grip portion 2b formed of, for example, a three-jaw chuck capable of increasing the grip force by a booster. The chuck 2 is rotatably supported by a rotating shaft 2a of a motor (not shown) provided in the centering device 1.

On the other hand, the receiving portion 3 is rotatably supported by the rotating shaft 3a and is movably supported in the X direction in the figure. An elastic member 4 such as a spring coil is externally inserted on the rotation shaft 3 a of the receiving portion 3.
Are pressed (pressed) in the X2 direction in the figure. At the tip (X2 side) of the receiving portion 3, a tapered portion 3 facing the chuck 2 is provided.
b is provided. The center of the rotation shaft 2a of the chuck 2 and the center of the rotation shaft 3a of the receiving portion 3 are both m-
It is provided so as to coincide with the center line of the centering device indicated by m.

Reference numeral 7 denotes an object to be measured (axial object) of the axial strain measuring device, such as a drill. Note that the left end side of the DUT 7 is the base 7a, and the right end side is the cutting edge, that is, the tip 7b. As shown in FIG. 3, when measuring the DUT 7 with the axial strain measuring device, the centering device 1 is used.
The DUT 7 is supported between the chuck 2 and the receiver 3.

That is, the base 7 a of the DUT 7 is gripped by the grip 2 b of the chuck 2. On the other hand, a tip portion 7b serving as a cutting edge of the DUT 7 is supported by the tapered portion 3b of the receiving portion 3. Since the receiving portion 3 receives the elastic force of the elastic member 4, the tip 7b of the measured object 7 is centered by following the tapered portion 3b of the receiving portion 3 pushed in the X2 direction. When the rotation of the chuck 2 is given by the motor in such a state, the receiving part 3 is simultaneously rotated following the rotation. As shown in FIG. 3, a plurality of strain sensors 8 are provided below the DUT 7 in parallel in the long axis (X) direction, and the distortion of the DUT 7 around the axis (radial direction) can be measured. Done.

[0007]

The shape of the receiving portion 3 is a tapered portion 3b formed of an inclined surface, and
Is directly supported. Originally, this tapered part 3
b against the tip 7b of the DUT 7
The tip 7b is centered so that the axial center thereof coincides with the center line mm. In an automated strain measurement device,
For example, the measured object 7 is supplied to the centering device by an automatic hand or a robot hand.

However, for example, when the object 7 has a sharp shape such as an axially extending cutting edge such as a drill for concrete drilling, both ends or one end of the cutting edge may be used. The measured object 7 hits the tapered portion 3b.
In some cases, the friction between the distal end portion 7b and the tapered portion 3b increases, or the cutting edge bites into the tapered portion, and the axial center of the distal end portion 7b cannot be aligned with the center line mm.

The present invention has been made to solve the above-mentioned conventional problems, and has a long axis (axial center) of an object to be measured (shaft-like object) having a tip end shape as a cutting edge like a concrete drill. It is an object of the present invention to provide a centering device for a shaft-like object having a cutting edge capable of accurately aligning the center line with the center line of the centering device.

[0010]

According to the present invention, there is provided an apparatus for centering a shaft having a cutting edge , comprising: a chuck for gripping a base of the shaft having a cutting edge at a tip thereof; and a receiving portion for supporting the cutting edge of the shaft. When, in the centering device of the shaft-like material having an elastic member that presses in a direction to approach the chuck to receiving portion, the receiving portion, the axis of the shaft-like material
Phosphorus around the center line (mm)
And a groove formed in the shape of a
With a plurality of rigid spheres arranged with a clearance margin in the circumferential direction of the groove
Is provided, and the rigid ball arranged in the annular shape is
The cutting edge is exposed so as to hit the cutting edge, and the cutting edge is
(Mm) sandwiched between the hard spheres at an axially symmetric position with respect to (mm)
By doing so, the axis center of the shaft-like object is aligned with the center line (m-
m).

According to the present invention, the tip of the shaft-like object is located in the receiving portion.
It is sandwiched between the provided hard spheres. Therefore, the shaft-like object can be positioned in a direction (radial direction) approaching the center line of the centering device connecting the chuck and the receiving portion. That is, the axial center of the shaft can be accurately aligned with the center line. In the above, in the case where the cutting edge of the shaft-like object is oriented in the opposite direction by 180 degrees, it is preferable that the number of the hard spheres provided in the receiving portion is an even number.

The distal end (blade edge) of the shaft-like object is sandwiched between a plurality of annularly arranged rigid spheres in an axially symmetric manner with respect to the center line mm (see FIG. 2A). Therefore, when the cutting edge is oriented in the opposite direction by 180 degrees, if the number of the hard spheres is even, each of the cutting edges of the shaft-like object is sandwiched between two adjacent hard spheres. At this time, the respective tips of the cutting edges that are oriented 180 degrees in the opposite direction can be sandwiched between the two hard spheres. Therefore, the plurality of hard balls arranged in an annular shape can be equally divided on both sides of the cutting edge of the shaft-like object. For this reason, the side surface of the cutting edge is supported by the rigid sphere with an even clamping force, and the axial center of the shaft can be aligned with the center line of the centering device.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. 1 is a sectional view showing a centering device for a shaft-like object having a cutting edge according to the present invention, FIG. 2 is an enlarged view of a receiving portion, (A) is a front view, and (B) is a sectional view.

The centering device shown in FIG. 1 includes a chuck 12, a strain sensor 18, a receiving portion 20, and the like, similarly to the above-described conventional centering device. That is, the chuck 12 is a three-jaw chuck or the like, and the gripping force can be increased by the booster. The center of the chuck 12 is a gripper 12b that grips a base 17a of an object (shaft) 17 such as a drill. The chuck 12 is rotatably attached to a tip of a rotating shaft 12a of a motor (not shown). The rotating shaft 12a of this motor is accurately positioned on the center axis mm of the centering device.

A plurality of strain sensors 18 are provided below the DUT 17 in the X direction in the drawing.
7, the measurement of the distortion around the axis (radial direction) of the object 17 can be performed.

As shown in FIG. 2 (B), the receiving portion 20 is provided at the end of a rotating shaft 14 which is provided rotatably and movably in the X direction. This rotating shaft 14
It is accurately positioned on the center axis mm of the centering device. An elastic member 15 made of a spring coil or the like is externally inserted into the rotating shaft 14, so that the receiving portion 20 can be elastically pressed (pressed) in the X2 direction in the figure.

The receiving portion 20 comprises a pedestal 21, a holding member 22, and an outer frame 23. The pedestal 21 is a joint member fixed to the rotating shaft 14. Pedestal 21
Is formed so as to protrude in the X2 direction, and a ring-shaped inner ring groove 21a is provided around the edge of the tip.

The holding member 22 is a ring-shaped member having an insertion hole 22b in the center, and is fixed to the end face of the pedestal 21 on the X2 side by mounting screws 13,13. An outer ring groove 22a is formed on the inner peripheral surface of the holding member 22,
The pressing member 22 faces the inner ring groove 21a.

As shown in FIGS. 2A and 2B, a plurality of rigid spheres 24 are provided between the inner ring groove 21a of the pedestal 21 and the outer ring groove 22a of the pressing member 22. The number of the hard spheres 24 is at least four or more even numbers.
In the case shown in (A), eight are provided. A lubricant such as grease is applied between the inner ring groove 21a and the outer ring groove 22a, and the hard sphere 24 is formed between the inner ring groove 21a and the outer ring groove 2a.
2a, a clockwise direction α1 and a counterclockwise direction α
2 can be moved smoothly.

The outer frame 23 includes the pedestal 21 and the holding member 22.
Are fixed by fastening members 26, 26 to the end face on the X2 side. Each of the fastening members 26 has a ball at its tip, and the ball presses the V groove between the boundary between the pedestal 21 and the pressing member 22. Therefore, the outer frame 23 is X2
Can be mounted in any direction. In the center of the outer frame 23, a hole 21b of the base 21 and an insertion hole 22b of the pressing member 22 are provided.
A through hole 23a is formed continuously with the through hole 23a. Through hole 23
The X2 side of a is a tapered surface 23b. The tapered surface 23b guides the leading end of the shaft into the through hole 23a.

As shown in FIG. 2A, each of the rigid balls 24 arranged in an annular shape has a portion corresponding to a hemisphere of the outer frame 2.
3 is exposed in the center line mm direction from the through hole 23a. Further, a clearance is formed between the rigid balls 24 adjacent to each other, and the total clearance in the circumferential direction of the entire rigid balls 24 arranged in a ring is set to about 0.2 mm. Have been.

In the centering device constructed as described above, the base 17a of the workpiece (shaft) 17 is gripped by the grip portion 12b of the chuck 12, and the tip 17b serving as the cutting edge of the workpiece 17 is fixed to the above-mentioned position. It is supported by the receiving part 20.

In this centering device, the DUT 17
Is supplied by an automated hand or robot hand. In the centering device, in a preparation stage before the measured object 17 is supplied, the receiving portion 20 is at a position separated in the X1 direction in the drawing. Then, the DUT 17 supplied by the automatic hand, the robot hand, or the like is first placed on the holding portion 12b of the chuck 12 of the centering device.
Is gripped. Next, the receiving portion 20 is moved in a direction (X2 direction) approaching the chuck 12, and the receiving portion 20 holds the tip portion 17 b of the DUT 17.

As shown in FIG. 2 (B), when the tip 17b of the DUT 17 has a cutting edge extending in the axial direction, and the cutting edge is oriented in the opposite direction by 180 degrees, the cutting edge is annular. The rigid balls 24 provided are supported so as to be divided. For example, one end 17A of the tip of the cutting edge is rigid balls 24a and 24a.
b, the other end 17B of the cutting edge is a rigid sphere 24a 'and a rigid sphere 24a whose axis is symmetric about the center line mm.
b '.

However, since the total gap size between the annularly arranged rigid spheres 24 is set to be as narrow as about 0.2 mm, the tips 17A and 17B of the cutting edges are more pedestal than the spherical center 24A of each of the rigid spheres 24. It does not approach in the 21 direction (X1 direction), and the tips 17A and 17B of the cutting edge are prevented from contacting the pedestal 21.

In FIG. 2A, the direction in which the cutting edge of the workpiece 17 held between the rigid spheres 24a, 24b and the rigid spheres 24a ', 24b' extends is indicated by a direction line EE. Hard ball 2
The number of 4 is set to an even number, and the number of the hard spheres 24 divided by the cutting edge of the workpiece 17 is the same on both sides of the direction line EE. In FIG. 2A, the cutting edge is divided into four on one surface and four on the other surface. And both sides of the tips 17A and 17B of the cutting edge are
The hard spheres 24a, 24b and the hard spheres 24a ', 24 respectively
b 'supports it with an even clamping force. The object to be measured (axial object) 17
Of the center of the center of the centering device
Can be aligned.

[0027]

When a predetermined rotation is given to the DUT 17 whose axial center is aligned with the center line mm, the DUT 17 can rotate around the center line mm. . Therefore, by measuring with the plurality of strain sensors 18, it is possible to accurately detect the strain in the direction around the axis (radius) of the measured object (shaft) 17. Note that FIG.
As shown in (B), a hole 21b is formed in the center of the pedestal 21 (a portion protruding in the X2 direction), and the inner surface thereof is formed in a tapered shape so that the tip of the measured object has a pointed shape. Can be aligned in the same manner as described above.

[0029]

According to the present invention described in detail above, the center of the object to be measured (shaft) having a cutting edge at the tip can be accurately aligned with the center line of the centering device.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a centering device for a shaft-like object having a cutting edge at a tip end according to the present invention;

FIGS. 2A and 2B are enlarged views of a receiving portion, wherein FIG.
Is a sectional view,

FIG. 3 is a partially enlarged view showing a conventional centering device for a shaft-like object,

[Explanation of symbols]

 Reference Signs List 12 chuck 14 rotating shaft 15 elastic member 17 workpiece (shaft) 17a base of shaft 17b distal end of shaft 17A, 17B blade edge of shaft 18 strain sensor 20 receiving portion 21 pedestal 22 pressing member 23 Outer frame 24, 24a, 24b, 24a ', 24b' Hard sphere 24A Spherical center E-E Direction line of the blade edge of the shaft-shaped object mm-m Center line of the shaft-shaped object

Claims (2)

(57) [Claims] A chuck for gripping a base of a shaft having a cutting edge at a tip , a receiving portion for supporting a cutting edge of the shaft, and an elastic member for pressing the receiving portion toward the chuck. In the centering device for a shaft-like object provided with: a center of the shaft of the shaft-like object is aligned with the receiving portion.
Formed in a ring around the center line (mm)
And a groove arranged in the groove in the groove in the circumferential direction of the groove.
A plurality of rigid balls arranged with a margin are provided,
The hard spheres arranged in an annular shape hit the cutting edge of the shaft-like object.
So that the cutting edge is aligned with the center line (mm).
By being sandwiched between the hard spheres at an axially symmetric position,
The axis center of the object is positioned at the center line (mm).
Centering device of the shaft-like material having a cutting edge, characterized in that it is. 2. The centering device for a shaft-like object having a cutting edge according to claim 1, wherein the number of the hard spheres provided in the receiving portion is set to an even number.