JPH033709A - Spindle - Google Patents

Abstract

PURPOSE:To obtain strong gripping force by forming a rotor cylindrical, forming a fastening porting portion having a taper hole widened in the direction of the top end thereof at the top end portion, inserting a collet in the taper hole in an axial direction slidably, and also disposing a spring between the rear end portion of the collet and the rotor. CONSTITUTION:A collet opening/closing mechanism 36 is operated to push and move a collet 29 in an axial direction and in the direction of the top end thereof with resistance to the urging force of a spring 35, the gripping portion 31 of the collet 29 is released by the fastening in a centripetal direction due to the taper hole 27 of a fastening portion 28 and is opened in a centrifugal direction, the pressing of the collet 29 by the collet opening/closing mechanism 36 is released and the collet 29 is shifted in a rear end direction by the urging force of the spring 35. The gripping portion 31 is pressed in a centripetal direction by the taper hole 27 and is closed thereby. The collet 29 is shifted in the top end direction, a tool is inserted in the gripping portion 31 and the collet 29 is shifted in the rear end direction and the gripping portion is pressed to the outer circumference of the tool 30 to be gripped thereby. Consequently, the urging force of the spring 35 is increased and the strong gripping force can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a spindle suitable for drilling printed circuit boards.

[Conventional technology] For drilling holes in printed circuit boards, a rotor with an integrated steel core is installed with bearings in the radial direction around its outer periphery, and bearings are placed in the thrust direction on a flange provided around the periphery of the rotor. Therefore, a type of spindle rotatably supported by a spindle body is widely used.

A tool holding mechanism for holding a tool is provided at the tip of the rotor. Conventionally, a centrifugal collet as shown in FIG. 2 has been used as this tool holding mechanism. To explain this centrifugal collet with reference to the same figure, the spindle body 1
A hole 3 that opens at the tip and has an appropriate depth in the axial direction is formed at the tip of the rotor 2, which is rotatably supported around its axis. A guide portion 6 is provided with a fitting hole 5 into which the hole 3 is fitted.
A cylindrical guide part 8 having a fitting hole 7 in the center for fitting the tool 4 is formed at the bottom of the hole 3 to protrude in the axial direction with a certain gap from the inner periphery of the hole 3. The fitting hole 5 of No. 6 and the fitting hole 7 of the cylindrical guide portion 8 are each set to fit with the tool 4 with a concentricity fitting tolerance of several microns.

Further, in the hole 3, there is a fitting hole 9 into which the tool 4 is fitted, and a certain gap 1 between the cylindrical guide part 8 and the inner circumference of the hole 3.
A centrifugal piece 13 having a fitting hole 12 having a diameter of 0.11 is provided, and the centrifugal piece 13 is closed by an O-ring 14 when the centrifugal piece 13 is in a stopped state. It is supported to maintain ++. Further, the fitting hole 9 of the centrifugal piece 13 into which the tool 4 is fitted is set so that the tool 4 and the fitting holes 5 and 7 are fitted with the same tolerance. The tool 4 is inserted into the fitting hole 5. while stopped by the O-ring 15.
7.9 It is designed to prevent it from pulling out and falling.

When the rotor 2 rotates, the centrifugal piece 13 rotates eccentrically with the rotation of the rotor 2, and the center of gravity of the rotation shifts due to the eccentric rotation. The resulting centrifugal force acts in the centrifugal direction to generate a couple centered on the drawing, and a force to hold the tool 4 is generated by the reaction force of the fitting surfaces of the fitting holes 5 and 7 and the friction coefficient of the original. is retained.

[Problems to be Solved by the Invention] According to the centrifugal collet used as the conventional tool holding mechanism described above, high-speed rotation of the rotor is required to obtain a strong holding force, and the holding force for tools with a large diameter is low. Conventionally used centrifugal collets require a rotation speed of 30,000 revolutions or more, and if the rotation speed is less than that, sufficient holding force cannot be obtained and the collet and tool may slip. The diameter of the tool must be 2.0 mm or less, and if it is more than 2゜0IIli1, sufficient holding force cannot be obtained, and if the rotation speed is less than 30,000 rotations or the diameter of the tool is 2゜0II
If the rotation speed exceeds m, the collet and tool will slip and the tool will not be able to obtain the required rotation speed, which may damage the inner surface of the hole and degrade the hole quality, or increase the load on the tool. This may cause problems such as breaking the tool.

The diameter of the tool required to actually drill holes in printed circuit boards is up to 6mm.
35mm, and the appropriate number of rotations required for this tool is 15,000.
It's a thousand revolutions.

For this reason, conventional centrifugal collets have the disadvantage that they can only be used in a very narrow range for drilling holes in printed circuit boards.

Furthermore, it also has the disadvantage that it is troublesome to attach and remove tools.

The present invention provides a spindle which aims to eliminate the above-mentioned drawbacks.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention provides a rotor with an integrated steel core, a radial direction bearing is arranged around the outer periphery of the rotor, and a flange provided on the outer periphery of the rotor is provided with a thrust bearing. In a spindle of a type in which a bearing in the direction is disposed and is rotatably supported on a spindle body, the rotor is formed into a cylindrical shape, and a tightening part having a tapered hole expanding in the direction of the tip is formed at the tip thereof, and the rotor is rotatably supported by the spindle body. A collet that has a gripping part that opens in the tapered hole of the tightening part by moving toward the tip, is compressed by the inner circumferential surface of the tapered hole and closes by moving toward the rear end, and clamps the tool inside. A spring is interposed between the rear end of the collet and the rotor to bias the collet toward the rear end, and the spindle body is provided with a spring that reciprocates in the axial direction. A configuration was adopted in which the collet is opened and closed by moving in the direction, and the collet is pushed in the direction of the tip by the elastic force of the spring.

In the collet opening/closing tank, a push rod is supported by passing through a thrust bearing disposed on the rear end side of the rotor so as to be movable in the axial direction of the rotor, and the tip side of the push rod is supported by a thrust bearing disposed on the rear end side of the rotor. A dicephragm is provided on the rear end side of the push rod, and a spring is installed between the dicephragm and the thrust bearing to bias the push rod toward the rear end, and the diaphragm is inserted into the thrust bearing. A diaphragm cover is provided to form an airtight chamber between the diaphragm cover and the diaphragm cover, which has an air vent that forces air into the airtight chamber to operate the diaphragm, move the push rod toward the tip, and push the collet. A configuration was adopted that formed the following.

[Function] The cororor is formed into a cylindrical shape, and the tip thereof is formed with a tightening portion having a tapered hole that widens toward the tip. As a result of the movement of the taper hole, a collet having a grip portion that is compressed and closed by the inner circumferential surface of the taper hole and that clamps a tool therein is slidably inserted in the axial direction, and the rear end of the collet is connected to the rotor. A spring is inserted between the spindle bodies to urge the collet toward the rear end, and the spindle body reciprocates in the axial direction and moves toward the tip, so that the collet is supported by the elastic force of the spring and is biased toward the tip. Since I thought of a collet opening/closing mechanism that pushes the collet, I operate the collet opening/closing mechanism and push the collet toward the tip in the axial direction by using the elastic force of the spring to move the collet. When the collet is released from the centripetal tightening and opened in the centrifugal direction, and the pressure on the collet by the collet opening/closing mechanism is released, the collet that had been pushed toward the tip is moved toward the rear end due to the elastic force of the spring. The gripping portion is closed by being pressed in the centripetal direction by the tapered hole of the tightening portion. Therefore, when attaching or detaching a tool to a collet, move the collet toward the distal end, insert the tool into the grip that opens in the centrifugal direction, and then move the collet toward the rear end. A gripping portion that closes in the direction is pressed and gripped on the outer periphery of the gripping portion. Thereafter, when the collet holding the tool is moved toward the tip, the gripping portion opens and the tool can be taken out.

The collet opening/closing mechanism includes a thrust bearing disposed at the rear end of the rotor that passes through and supports a push rod so as to be movable in the axial direction of the rotor, and the tip end of the push rod is inserted into the rotor. At the same time, a diaphragm is provided on the rear end side of the push rod, a spring is provided between the diaphragm and the thrust bearing to bias the push rod toward the rear end, and a spring is provided between the thrust bearing and the diaphragm. A diaphragm cover was provided to form an airtight chamber, and this diaphragm cover had an air hole for forcing air into the air chamber to operate the diaphragm, move the push rod toward the tip, and push the collet. When air is forced into the airtight chamber from the air vent, the diaphragm receives the air and deforms toward the tip. Due to the deformation of the diaphragm, the push rod is moved toward the tip by the elastic force of the spring, and the collet When the push rod is pressed in the same direction to remove air from the airtight chamber, the moved push rod moves toward the rear end due to the elastic force of the spring, releasing the pressure on the collet.

[Examples] Hereinafter, the present invention will be described in detail based on the drawings, but the present invention (but not limited to the examples).

In Atsushi 1 figure, 16 is a cylindrical spindle body, 17
18.19 is a rotor supported within the spindle body 16 so as to be rotatable about its axis and movable in the axial direction; 18.19 is a radial static pressure bearing disposed around the outer periphery of the rotor 17;
22 and 23 are air passages that guide air to each static pressure surface of the radial static pressure bearings 18 and 19 and the thrust static pressure bearing 2o; 24; is a connecting rod that reciprocates the rotor 17 in the axial direction with respect to the spindle body 16.

Reference numeral 25 indicates a copper core formed integrally with the rotor 17 at approximately the center in the axial direction of the rotor 17, and reference numeral 26 indicates a motor coil wound around the copper core 25.

The main body of the rotor 17 is formed into a cylindrical body, and a tightening portion 28 is provided at the tip thereof with a tapered hole 27 that expands toward the tip, that is, becomes gradually larger in diameter toward the tip.
is formed protrudingly.

This tapered hole 27 is coaxial with the rotor 17 and communicates with the inside of the rotor 17.

Reference numeral 29 denotes a collet movably inserted into the taper hole 27 of the tightening portion 28. The gripping portion 31 has an insertion hole 33 that is open at the tip and into which the tool 30 is inserted.
It has a structure in which a slit 34 is formed in the axial direction on the outer periphery of the cylindrical body, and when the collet 29 moves toward the rear end,
The gripping part 31 has a tightening part 2 whose diameter gradually decreases toward the rear end.
When the insertion hole 33 is closed by the inner circumferential surface of the tapered hole 27 of No. 8 and the collet 29 is moved toward the distal end, the gripping portion 31 is released from the narrowing pressure caused by the tapered hole 27 and centrifugally closed. It opens in the direction. Inside the rotor 17, there is a bulge 32 at the rear end of the collet 29.
A spring 35 that urges the collet 29 toward the rear end is interposed between the end step of the rotor 17 and the collet 29, and the elastic force of the spring 35 normally moves the collet 29 toward the rear end. The gripping portion 31 is in a closed state, and the collet 29 is moved toward the distal end by the elastic force of the spring 35, thereby opening the gripping portion 31.

This collet 29 is pushed and moved toward the distal end by a collet opening/closing mechanism 36.

2. The collet opening/closing mechanism 36 is configured as follows. A push rod 37 is supported by a thrust static pressure bearing 2o disposed on the rear end side of the rotor 17 so as to be movable in the axial direction thereof. The tip end of the push rod 37 is inserted into the rotor 17, and the tip is located close to the bulge 32 of the collet 29 that is moving toward the rear end. A diamond slam 38 is provided, and a spring 39 is interposed between the diamond slam 38 and the thrust static pressure bearing 20 to bias the push rod 37 toward the rear end. Further, the thrust static pressure bearing 20 is provided with a diaphragm cover 41 that forms an airtight chamber 40 in conjunction with the daisephram 38, and this diaphragm cover 41 has an air hole 42 that pumps air into the airtight chamber 4o. is formed. By pumping air into the airtight chamber 40 from the air hole 42, the diamond slam 38 deforms in response to the air, and the push rod 37 is moved toward the distal end by the elastic force of the spring 39. The tip presses the collet 29 to move it in the same direction, and by releasing air from the airtight chamber 40, the diamond slam 38 is released from the air pressure, and the spring 39
The resilient force causes the bushing 37 to return to its original shape and move toward the rear end, thereby releasing the push rod 37 from pressing the collet 29.

[Effects of the Invention] As described above, according to the present invention, the gripping portion that grips the tool opens and closes by moving the collet in the axial direction, so the tool can be easily attached and detached, and the gripping force of the collet on the tool is reduced. can be determined by the elastic force of the spring that urges the collet toward the rear end, and by strengthening the elastic force of this spring, a stronger gripping force can be obtained. Since it is not affected by the rotation speed at all, the necessary strong gripping force can be obtained regardless of the rotation speed of the rotor (and regardless of the diameter of the tool). All the necessary tools from large diameter to small diameter can be set, and holes can be drilled at a predetermined rotation speed appropriate for each tool.

Furthermore, since the collet opening/closing mechanism for opening and closing the collet can be performed by a simple operation such as sending air into the airtight chamber, tool exchange can be more easily automated.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the present invention, and FIG. 2 is a sectional view showing a conventional spindle holding mechanism. 16... Spindle body 17... Rotor 18
．． 19... Radial bearing 20... Thrust bearing 21... Flange 25.
...Copper core 27...Tapered hole 28...Tightening part
29... Collet 30... Tool 31... Collet opening/closing mechanism 37... Push rod 38... Diaphragm 39... Spring 40... Airtight chamber 41...
Diaphragm cover 42...Air vent 5

Claims (2)

[Claims] (1) A type in which a rotor with an integrated steel core is rotatably supported by a spindle body, with a radial bearing placed around its outer periphery and a thrust bearing placed on a flange provided on the outer periphery of the rotor. In the spindle of
The rotor is formed into a cylindrical shape, and a tightening part having a tapered hole that widens in the distal direction is formed at the distal end of the rotor, and the tapered hole of the tightening part opens when moved toward the distal end and moves toward the rear end. A collet having a grip portion that is compressed and closed by the inner circumferential surface of the tapered hole to clamp a tool therein is slidably inserted in the axial direction, and the collet is inserted between the rear end of the collet and the rotor. A spring is interposed in the spindle body to urge the collet toward the rear end, and the spindle body is provided with a spring that reciprocates in the axial direction and moves toward the tip, and the collet is pushed toward the tip by the elastic force of the spring. A spindle equipped with a moving collet opening/closing mechanism. (2) In the collet opening/closing mechanism, a push rod is supported by penetrating the thrust bearing disposed at the rear end of the rotor so as to be movable in the axial direction of the rotor, and the tip end of the push rod is inserted into the rotor. At the same time, a diaphragm is provided on the rear end side of the push rod, a spring is provided between the diaphragm and the thrust bearing to bias the push rod toward the rear end, and a spring is provided between the thrust bearing and the diaphragm. A diaphragm cover was provided to form an airtight lid, and this diaphragm cover had an air hole for forcing air into the airtight lid to operate the diaphragm, move the push rod toward the tip, and push the collet. The spindle according to claim 1, comprising: