JP2002039207A - Tool driving apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent transmission of the movement of a rotational shaft to a main shaft even if whirling or the like of the rotational shaft occurs, to stabilize the main shaft to normally rotate thereby to make the tool suitably operate. SOLUTION: A radial direction and a thrust direction of the main shaft 3 are supported in a non-contact manner by using two air bearings 41, 42. The main shaft 3 and the rotational shaft 5 rotatably driven by belt drive are linked by means of a coupling 7, so that the rotations of the rotational shaft 5 is transmitted to the main shaft 3, and the movement of the rotational shaft 5 other than the rotation is allowed while preventing the transmission of the movement to the main shaft 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tool driving device used for a machine tool such as grinding.

[0002]

2. Description of the Related Art Generally, in a tool driving device of this type, a main shaft having a mounting portion for a grinding tool and a rotary shaft for rotationally driving the main shaft are mounted on a housing while supported by bearings. When an external motor unit is used for the drive unit of the tool driving device, a pulley is attached to the shaft end of the rotating shaft, and the belt is tensioned between the pulley and the pulley attached to the rotating shaft of the motor unit. , And the rotation shaft is driven to rotate by belt transmission.

[0003]

However, in the conventional tool driving device, when a pulley is attached to a shaft end of a rotating shaft for rotating the main shaft and the rotating shaft is driven to rotate by belt transmission, Since the rotating shaft is swung or pulled in the direction of coming out of the housing, there is a problem that this movement is transmitted to the main shaft and affects the tool mounted on the shaft end. The present invention solves such a conventional problem, and in this type of tool driving device, even if whirling or movement in a pulling-out direction occurs on a rotating shaft that is rotationally driven, the movement of the rotating shaft is used as a main shaft. An object of the present invention is to stably and normally rotate a main shaft without transmitting power and to appropriately operate a tool.

[0004]

In order to achieve the above object, a tool driving device according to a first aspect of the present invention supports a main spindle having a tool mounting portion at a shaft end and a non-contact main spindle. A hydrostatic bearing, a rotating shaft supported coaxially with the main shaft via a bearing, and rotationally driven by a driving unit, and a pin insertion portion and a joint provided at shaft ends of the main shaft and the rotating shaft facing each other. A shaft end joint having a pin, an intermediate joint interposed between the main shaft and the rotating shaft and having a joint pin and a pin insertion portion engageable with each of the two shaft end joints. And a shaft coupling which transmits the rotation of the rotary shaft to the main shaft and does not transmit any movement other than the rotation of the rotary shaft to the main shaft. According to a second aspect of the present invention, there is provided a tool driving device according to the first aspect, wherein the plurality of hydrostatic fluid bearings are arranged in series so as to be supported along substantially the entire length of the main shaft. It is. According to a third aspect of the present invention, there is provided a tool driving device according to the first or second aspect, wherein the hydrostatic bearing is:
It comprises a radial bearing that supports the main shaft in the radial direction, and a thrust bearing that supports the main shaft in the thrust direction. According to a fourth aspect of the present invention, in the tool driving device according to the third aspect, the radial bearing includes a plurality of orifices in a circumferential direction at a plurality of positions in the axial direction. According to a fifth aspect of the present invention, in the tool driving device according to the third or fourth aspect, the thrust bearing includes a plurality of orifices in a circumferential direction. According to a sixth aspect of the present invention, in the tool driving device according to any one of the first to fifth aspects, an air bearing is used as the hydrostatic bearing. According to a seventh aspect of the present invention, in the tool driving device according to any one of the first to sixth aspects, the driving unit includes an external motor unit, the rotary shaft includes a pulley at an axial end, and a belt transmission. Is driven to rotate. The tool driving device according to claim 8 of the present invention is the tool driving device according to any one of claims 1 to 6, wherein the driving unit is configured by an air motor or an electric motor, and the rotating shaft is directly connected to the air motor or the electric motor,
It is driven in rotation. According to a ninth aspect of the present invention, in the tool driving device according to any one of the first to eighth aspects, the shaft end joint on the main shaft side of the shaft joint has a pin inserted through a center of the shaft end in an axial direction. Part and a plurality of joint pins protruding in the axial direction at equal intervals in the circumferential direction around the part, and the shaft end joint on the rotating shaft side is a pin insertion part bored in the center of the shaft end in the axial direction. And a plurality of joint pins protruding in the axial direction in a staggered arrangement with the joint pins on the main shaft side at equal intervals in the circumferential direction and around the intermediate joint,
It comprises a pin that can be inserted into each of the pin insertion portions on the main shaft side and the rotation shaft side, and a flange formed on the peripheral surface and that has a plurality of pin insertion portions through which the respective joint pins of the main shaft and the rotation shaft can be inserted. A tool driving device according to a tenth aspect of the present invention is the tool driving device according to any one of the first to ninth aspects, wherein an O-ring is attached to each joint pin. According to the above configuration, even if whirling or movement in the pull-out direction occurs on the rotationally driven rotary shaft, only the rotation of the rotary shaft is transmitted to the main shaft without transmitting such movement of the rotary shaft to the main shaft. can do. In addition, since the main shaft is supported by the hydrostatic bearing in a non-contact manner, the main shaft can be rotated stably and normally.

[0005]

Embodiments of the present invention will be described below. (Embodiment 1) FIG. 1 shows a first embodiment of the present invention. In this embodiment, a tool driving device used for a machine tool such as a grinder is illustrated. In FIG. 1, a tool driving device 1 includes a housing 2, a main shaft 3 to which a grinding tool is attached, a hydrostatic fluid bearing 4 supporting the main shaft 3, a rotating shaft 5 rotating the main shaft 3, and a rotating shaft 5. It comprises a supporting rolling bearing 6 and a shaft coupling 7 for connecting the main shaft 3 and the rotary shaft 5.

The housing 2 has a front bearing fixing portion 21 for the hydrostatic bearing 4 and a rear bearing fixing portion 22 for the rolling bearing 6 on its inner peripheral surface. Further, an air supply port 23 is attached to the outer peripheral surface, and the air flow path 24 is formed around the front bearing fixing portion 21 in a direction parallel to the axial direction and at a right angle. The air outlet 25 is provided at a predetermined position on the inner peripheral surface of the front bearing fixing portion 21.

The main shaft 3 is provided with a mounting portion 31 for attaching a grinding wheel of a grinding tool at a front end portion, and a flange 32 protruding in an outer peripheral direction at a rear end portion.

[0008] Two air bearings 41, 4 are attached to the hydrostatic bearing 4.
2 is used. One of the air bearings 41 is a radial bearing that supports the radial direction of substantially half of the tip end side of the main shaft 3 in a non-contact manner, and has a circumferential surface at a predetermined position in the axial direction, here a position close to both open ends. Each is provided with ten orifices 40 in the circumferential direction. The other air bearing 42 includes a radial bearing 421 that supports the radial direction of substantially half of the rear end side of the main shaft 3 in a non-contact manner,
A thrust direction bearing 422 for supporting the thrust direction of the main shaft 3 in a non-contact manner. On the circumferential surface of the radial bearing 421, there are ten orifices 40 in the circumferential direction at predetermined positions in the axial direction, in this case, positions close to both open ends.
Are drilled. The thrust bearing 422 is composed of a pair of members having a large outer diameter formed at one opening end of the radial bearing 421, and a plurality of members are provided on each surface of these members in a circumferential direction and opposed to each other. An orifice 40 is formed. Thus, the two air bearings 41, 4
2 is arranged and fixed in series to the front bearing fixing portion 21 of the housing 2, and each orifice 40 is connected to each air outlet 25 on the inner peripheral surface of the front bearing fixing portion 21. The main shaft 3 is supported by these air bearings 41 and 42 along substantially the entire length thereof, and the mounting portion 31 of the tool at the tip is externally (frontward).
The flange 32 of the main shaft 3 is supported by a thrust bearing 422 of the rear air bearing 42.

The rotating shaft 5 has a pulley 50 at the shaft end. The rolling bearing 6 is fixed to the rear bearing fixing portion 22 of the housing 2, and the rotating shaft 5 is supported by the rolling bearing 6. An external motor unit is used for the drive unit of the rotating shaft 5, and a belt is wound around the pulley 50 of the rotating shaft 5 and a pulley attached to the rotating shaft of a motor unit (not shown) in a tight state.

The shaft coupling 7 includes pin insertion portions 711 and 7 provided at shaft ends of the main shaft 3 and the rotating shaft 5 that face each other.
21 and shaft end joint 7 having joint pins 712, 722
1 and 72 and a joint pin 7 interposed between the main shaft 3 and the rotating shaft 5 and capable of engaging with the shaft end joints 71 and 72 of these two shafts.
02 and an intermediate joint 70 having a pin insertion portion 701.

As shown in FIG. 2, a shaft end joint 7 on the main shaft 3 side is provided.
1 is a pin insertion portion 711 that is bored in the center thereof in the axial direction.
And three joint pins 712 protruding in the axial direction around the circumference thereof at equal intervals in the circumferential direction. Grooves 713 are formed in the circumferential direction on the distal end side of each joint pin 712, and two О rings 714 are fitted in the grooves 713.
The shaft end joint 72 on the side of the rotary shaft 5 has a pin insertion portion 721 that is bored in the center in the axial direction and circumferentially equally spaced around the pin insertion portion 721, and is alternately arranged with the joint pin 712 on the main shaft 3 side. Three joint pins 722 protruding in the axial direction
And A groove 723 is formed in the circumferential direction on the distal end side of each joint pin 722, and a О ring 724 is formed in the groove 723.
The books are fitted one by one. The intermediate joint 70 is formed by drilling a pin 702 that can be inserted into each of the pin insertion portions 711 and 721 on the main shaft 3 side and the rotary shaft 5 side, and a flange 705 formed on the peripheral surface thereof. Each joint pin 712, 7
And six pin insertion portions 701 through which the X.22 can be inserted.
A groove 703 is formed on the tip end side of the pin 702 in the circumferential direction,
A О-ring 704 is fitted in the groove 703, and furthermore, a О-ring 704 is provided on the pin 702 adjacent to the flange 705.
Is fitted.

As shown in FIG. 3, a shaft end joint 7 on the main shaft 3 side is provided.
The pin 702 of the intermediate joint 70 is inserted into the center pin insertion portion 711 and the shaft end joint 7 on the main shaft 3 side.
One of the three joint pins 712 is inserted into the pin insertion portion 701 of the intermediate joint 70, and one side of the intermediate joint 70 is connected to the main shaft 3. Similarly, the shaft end joint 72 on the rotating shaft 5 side
The pin 702 of the intermediate joint 70 is inserted into the pin insertion portion 721 at the center of
Two three joint pins 722 are inserted into the pin insertion portions 701 of the intermediate joint 70, and the rotating shaft 5 is connected to one side and the other of the intermediate joint 70. With this coupling structure, the shaft end joint 71 and the intermediate joint 7 on the main shaft 3 side with respect to the rotation of the rotary shaft 5
0, the shaft end joints 72 on the side of the rotating shaft 5 are engaged with each other to transmit the rotation of the rotating shaft 5 to the main shaft 3, and the shaft ends on the side of the main shaft 3 for the movement other than the rotation of the rotating shaft 5. The joint 71, the intermediate joint 70, and the shaft end joint 72 on the side of the rotating shaft 5 do not engage with each other, and allow a movement other than the rotation occurring on the rotating shaft 5, and constitute a clutch mechanism that does not transmit this movement to the main shaft 3.

As shown in FIG. 1, a dustproof member 8 utilizing a labyrinth structure is provided at the rear end of the housing 2. The dustproof member 8 is formed of a cap-shaped member, and has a screw hole 80 at its center. This dustproof member 8
The rotary shaft 5 is passed through the screw hole 80, is screwed to a screw 51 formed on the peripheral surface of the rotary shaft 5, is mounted on the rotary shaft 5, and the outer peripheral portion of the dustproof member 8 is attached to the rear end surface of the housing 2. It is fitted in the formed groove 20. In this way, the dustproof member 8 is rotated together with the rotating shaft 5, and the gap around the rotating shaft 5 at the rear end surface of the housing 2 is closed, thereby preventing dust from entering.

In this manner, the tool driving device 1 includes the main shaft 3
Is supported by the two air bearings 41 and 42 in a non-contact manner, and is rotated by the rotation drive of the rotating shaft 5. That is,
The compressed air sent through the air supply port 23 on the outer peripheral surface of the housing 2 flows through the air flow path 24 around the front bearing fixing portion 21, and the compressed air is supplied to the air bearings 41 and 42 connected to the air outlets 25. The orifices 40 are squeezed out of the orifices 40, and the main shaft 3 is supported on the air bearings 41 and 42 in the radial direction and the thrust direction in a non-contact manner. The power of an external motor unit (not shown) is transmitted by a belt and a pulley 50 to drive the rotation shaft 5 to rotate.
The main shaft 3 connected via the shaft coupling 7 is rotated. At this time, the shaft end joint 71 on the main shaft 3 side, the intermediate joint 70, and the shaft end joint 72 on the rotary shaft 5 side, which constitute the shaft joint 7, are engaged with each other with respect to the rotation of the rotary shaft 5. 5 is transmitted to the main shaft 3, and the main shaft 3 is supported by the air bearings 41 and 42 in a non-contact manner and stably rotates normally. On the other hand, when a motion other than rotation such as whirling or pulling in the pull-out direction occurs on the rotary shaft 5, the shaft end joint 71 on the main shaft 3 side, the intermediate joint 70, and the shaft end joint 72 on the rotary shaft 5 side. Are not engaged with each other, and movement other than the rotation generated on the rotary shaft 5 is allowed, but is not transmitted to the main shaft 3, and the main shaft 3 is
1, 42 and rotate normally.

As described above, according to the first embodiment, 2
The two air bearings 41 and 42 are used to support the radial direction and the thrust direction of the main shaft 3 in a non-contact manner, and the main shaft 3 and a rotary shaft 5 driven to rotate by belt transmission are connected by a shaft coupling 7 to form a rotary shaft. 5 is transmitted to the main shaft 3 and the rotation other than the rotation is allowed to the rotation shaft 5 while this movement is not transmitted to the main shaft 3, so that the main shaft 3 can be rotated stably and normally. it can.

(Embodiment 2) FIG. 4 shows a second embodiment of the present invention. This embodiment also exemplifies a tool driving device used for a machine tool such as a grinding machine. In the case of the tool driving device 11, the configuration of the rotating shaft for rotating the main shaft 3 and the driving unit thereof is the first embodiment. And form.
Here, different parts will be denoted by new reference numerals, and the description will be added. Other parts will be denoted by the same reference numerals as in the first embodiment, and redundant description will be omitted.

Here, the rotating shaft and its driving section are constituted by a vane type air motor 9. This air motor 9
Is a cylinder 90 having an air supply port 91 and an exhaust port 92, a rotor 93 which is a rotary shaft inserted at a position eccentric with respect to the axis of the cylinder 90, and a peripheral surface of the rotor 93 via a spring means. A plurality of vanes 94 are attached, and a rolling bearing 60 is fixed to the rear bearing fixing portion 22 of the housing 2.
3 is supported and housed in the housing 2. A compressed air supply unit 95 and a compressed air discharge unit 96 are attached to the rear part of the housing 2, and these are connected to an air supply port 91 and an exhaust port 92 of the cylinder 90, respectively.

A shaft end joint 97 is fixed to one end of a rotor 93 of the air motor 9. This shaft end joint 97
Similarly to the shaft end joint 72 of the rotary shaft 5 in the first embodiment, a pin insertion portion 721 that is bored in the shaft center in the axial direction.
And three joint pins 722 circumferentially arranged at equal intervals in the circumferential direction and alternately arranged with the joint pins 712 on the main shaft 3 side and protruding in the axial direction. A groove 723 is formed in the circumferential direction on the distal end side of each joint pin 722, and two О rings 724 are fitted in the grooves 723.
The shaft end joint 97 is connected to the intermediate joint 70 and the main shaft 3
Is connected to the rotor 93.

In this way, the tool driving device 11 is rotatably driven by the air motor 9 with the main shaft 3 supported on the two air bearings 41 and 42 in the radial and thrust directions without contact. That is, compressed air is supplied from the compressed air supply unit 95, is sent to the cylinder 90 through the air supply port 91, and the vane 94 is pressed against the compressed air.
The rotor 93 is rotated. The compressed air is exhausted from the compressed air discharge section 96 through the exhaust port 92 as the rotor 93 rotates. With respect to the rotation of the rotor 93,
The shaft end joint 71 on the main shaft 3 side, the intermediate joint 70, and the shaft end joint 97 on the rotor 93 side that constitute the shaft joint 7 are mutually engaged,
The rotation of the rotor 93 is transmitted to the main shaft 3, and the main shaft 3 is supported by the air bearings 41 and 42 in a non-contact manner, and rotates stably and normally. On the other hand, when a motion other than rotation occurs in the rotor 93, the shaft end joint 71, the intermediate joint 70, and the shaft end joint 97 on the rotor 93 side do not engage with each other. The movement other than the generated rotation is allowed, but is not transmitted to the main shaft 3, and the main shaft 3 is provided with an air bearing 41,
Stable on 42 and rotates normally.

As described above, according to the second embodiment, 2
Using two air bearings 41 and 42, the radial direction and the thrust direction of the main shaft 3 are supported in a non-contact manner. The rotor 93 of the air motor 9 is connected to the main shaft 3 by the shaft coupling 7, and the rotation of the rotor 93 is transmitted to the main shaft 3. While transmitting, the rotor 9
Since the movement other than the rotation of the third shaft 3 is allowed, but this movement is not transmitted to the main shaft 3, the main shaft 3 can be rotated stably and normally.

In the second embodiment, the air motor can be replaced with an electric motor, and the same operation and effect can be obtained in this case.

[0022]

As described above, according to the present invention,
The main shaft is supported by hydrostatic bearings, and the rotating shaft is connected to the main shaft by a shaft coupling to transmit the rotation of the rotating shaft to the main shaft and allow movement other than rotation of the rotating shaft, while allowing this movement to the main shaft. Since the transmission is not performed, the main shaft can be stably and normally rotated even if the rotating shaft whirls or moves in the drawing direction, and the tool can be operated properly.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a tool driving device used for a machine tool such as a grinder shown as a first embodiment of the present invention.

FIG. 2 is an enlarged exploded perspective view of a shaft coupling used in the tool driving device.

FIG. 3 is an enlarged sectional view of a shaft coupling used in the tool driving device.

FIG. 4 is a cross-sectional view of a tool driving device used for a machine tool such as a grinder shown as a second embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 tool driving device 2 housing 20 groove 21 front bearing fixing portion 22 rear bearing fixing portion 23 air supply port 24 air flow passage 25 air outlet 3 main shaft 31 tool mounting portion 32 flange 4 hydrostatic fluid bearing 40 orifice 41 42 Air bearing 421 Radial bearing 422 Thrust bearing 5 Rotary shaft 50 Pulley 51 Screw 6, 60 Rolling bearing 7 Shaft joint 70 Intermediate joint 701 Pin insertion part 702 Joint pin 703 Groove 704 О Ring 705 Flange 71 Shaft end joint 711 Pin insertion Part 712 Joint pin 713 Groove 714 O-ring 72 Shaft end joint 721 Pin insertion portion 722 Joint pin 723 Groove 724 O-ring 8 Dust-proof member 80 Screw hole 11 Tool driving device 9 Air motor 90 Cylinder 91 Air supply port 92 Exhaust port 93 Rotor 94 Vane 95 Compressed air supply unit 96 the compressed air outlet 97 shaft end fittings

Claims (10)

[Claims] 1. A spindle having a tool mounting portion at a shaft end, a hydrostatic bearing for supporting the spindle in a non-contact manner, supported via a bearing coaxially with the spindle, and rotationally driven by a drive unit. A rotating shaft, a shaft end joint having a pin insertion portion and a joint pin respectively provided at shaft ends of the main shaft and the rotating shaft opposed to each other, and interposed between the main shaft and the rotating shaft, These two
A joint pin engageable with each of the shaft end joints of the shaft and an intermediate joint having a pin insertion portion, for transmitting rotation of the rotating shaft to the main shaft, and performing movement other than rotation of the rotating shaft to the main shaft. And a shaft coupling that does not transmit to the tool drive. 2. The tool drive device according to claim 1, wherein the hydrostatic bearing includes a plurality of hydrostatic bearings arranged in series so as to be supported along substantially the entire length of the main shaft. 3. The tool drive device according to claim 1, wherein the hydrostatic bearing includes a radial bearing that supports a radial direction of a main shaft, and a thrust bearing that supports a thrust direction of the main shaft. 4. The radial bearing has a plurality of orifices in a circumferential direction at a plurality of positions in an axial direction thereof.
The tool driving device according to claim 1. 5. The tool driving device according to claim 3, wherein the thrust bearing has a plurality of orifices in a circumferential direction. 6. The tool driving device according to claim 1, wherein an air bearing is used as the hydrostatic bearing. 7. The tool driving device according to claim 1, wherein the driving unit is constituted by an external motor unit, the rotating shaft has a pulley at an end of the shaft, and is driven to rotate by belt transmission. 8. The tool driving device according to claim 1, wherein the driving unit is constituted by an air motor or an electric motor, and the rotating shaft is directly connected to the air motor or the electric motor and is driven to rotate. 9. A shaft end joint on the main shaft side of the shaft joint has a pin insertion portion formed in the center of the shaft end in an axial direction, and a plurality of axially protruding portions around the pin insertion portion at circumferentially equal intervals. A coupling pin is provided, and the shaft end coupling on the rotating shaft side is provided with a pin insertion portion that is bored in the axial direction at the center of the shaft end and around the same at circumferentially equal intervals, and alternately with the coupling pin on the main shaft side. A plurality of joint pins protruding in the axial direction in an array, wherein the intermediate joint is formed on a pin that can be inserted into each of the pin insertion portions on the main shaft side and the rotating shaft side and on a peripheral surface thereof, and the main shaft and the rotation The tool drive device according to any one of claims 1 to 8, further comprising: a flange having a plurality of pin insertion portions through which each joint pin of the shaft can be inserted. 10. The tool driving device according to claim 1, wherein a О ring is attached to each joint pin.