JP2018075645A - Tool diameter variable main shaft apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To change a tool diameter around a main shaft of the tool; and to miniaturize the whole apparatus.SOLUTION: A tool diameter variable main shaft apparatus includes a main shaft 3, an eccentric shaft 4 having a tool 5, and arranged eccentrically in the main shaft 3, and a motor 6 for the eccentric shaft for rotating the eccentric shaft 4 relative to the main shaft 3, in which a tool diameter around the main shaft 3 of the tool 5 can be changed by rotating the eccentric shaft 4. The motor 6 for the eccentric shaft is arranged in the main shaft 3 on a shaft core 4b of the eccentric shaft 4 so as to be rotatable integrally with the main shaft 3. Deceleration means 7 arranged in the main shaft 3 is provided between the eccentric shaft 4 and the motor 6 for the eccentric shaft.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a tool diameter variable spindle device for a machine tool.

  The tool diameter variable spindle device for machine tools has a tool diameter drawn by the tool around the main shaft by rotating the eccentric shaft with respect to the main shaft. There are some which can change (processing diameter) as appropriate (Patent Documents 1 to 3).

  The tool diameter variable spindle device of Patent Document 1 includes an eccentric shaft motor arranged in parallel with the main shaft on the movable table side that rotatably supports the main shaft, and rotates the eccentric shaft by driving the eccentric shaft motor. A screw-type transmission mechanism and clamping means for fixing the eccentric shaft to the main shaft at an arbitrary rotational position are provided, the eccentric shaft is rotated via the transmission mechanism by driving the eccentric shaft motor, and the tool diameter is changed. After changing to the tool diameter, the eccentric shaft is fixed to the main shaft by the clamping means.

  Further, the tool diameter variable spindle device of Patent Document 2 includes a spindle motor arranged on the axis of the spindle and an eccentric shaft motor arranged in parallel with the spindle on the movable base side. The tool diameter is changed by rotating the eccentric shaft via a tool diameter variable mechanism by driving.

  Furthermore, the tool diameter variable spindle device of Patent Document 3 is configured such that the spindle and the eccentric shaft are formed in a flat shape in the axial direction, and a worm gear mechanism that meshes with the outer periphery of the eccentric shaft is provided in the spindle, on the axis of the spindle. An eccentric shaft motor arranged on the other end side rotates the eccentric shaft via a worm gear mechanism to change the tool diameter.

JP-A-7-204910 JP 2014-69290 A JP 2009-190157 A

  In the conventional tool diameter variable spindle device of Patent Documents 1 and 2, since the eccentric shaft motor is arranged on the movable base side in parallel with the spindle, there is a problem that the entire device including the eccentric shaft motor is enlarged. Also, it is impossible to change the tool diameter while the spindle is rotating.

  On the other hand, the conventional tool diameter variable spindle device of Patent Document 3 is configured so that the spindle and the eccentric shaft are flat in the axial direction, and the eccentric shaft, the worm gear mechanism, and the eccentric shaft motor are provided on the spindle side. The tool diameter can be changed during rotation of the main shaft, but there is a problem that the entire outer diameter including the main shaft becomes very large.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above-described conventional problems, and an object of the present invention is to provide a variable tool diameter spindle apparatus that can change the tool diameter around the spindle of the tool and that can downsize the entire apparatus.

  The present invention comprises a main shaft, an eccentric shaft having a tool and arranged eccentrically in the main shaft, and an eccentric shaft motor for rotating the eccentric shaft relative to the main shaft, and rotating the eccentric shaft. In the tool diameter variable spindle apparatus, the tool diameter of the tool around the spindle can be changed, and the eccentric shaft motor is arranged on the axis of the eccentric shaft so as to be rotatable integrally with the spindle. is there.

  A reduction means for reducing the rotation of the eccentric shaft motor may be provided between the eccentric shaft and the eccentric shaft motor. The eccentric shaft motor may be provided in the main shaft. The speed reduction means may be a wave gear device, and the wave gear device may be provided in the main shaft. A support member that rotatably supports the main shaft may be provided on the eccentric shaft motor side, and a slip ring for supplying power to the eccentric shaft motor may be provided between the main shaft and the support member.

  According to the present invention, since the eccentric shaft motor is arranged on the eccentric shaft core of the eccentric shaft so as to be rotatable integrally with the main shaft, the tool diameter can be changed during the rotation of the main shaft, and the entire apparatus is downsized. There are advantages you can do.

It is sectional drawing of the tool diameter variable main axis | shaft apparatus which shows the 1st Embodiment of this invention. It is an expanded sectional view of the principal part. It is explanatory drawing of the eccentric amount of the same spindle, an eccentric shaft, and a tool. It is a partially broken side view of the wave gear device. It is explanatory drawing of the tool diameter of the tool. It is explanatory drawing of the eccentric amount of the main axis | shaft which shows the 2nd Embodiment of this invention, an eccentric shaft, and a tool. It is explanatory drawing of the tool diameter of the tool.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  1 to 5 illustrate a first embodiment of a tool diameter variable spindle device for a machine tool according to the present invention. FIG. 1 shows an outline of a variable tool diameter spindle device, and its main part is shown in FIG.

  As shown in FIGS. 1 and 2, the variable tool diameter spindle device includes a movable base 1 arranged to be reciprocally movable in the front-rear direction, a bearing case 2 fixed to the movable base 1 in the front-rear direction, A main shaft 3 that is rotatably arranged in the bearing case 2 and has an axial core 3b in the front-rear direction, and an axial core that is rotatably arranged in the main shaft 3 and is eccentric from the shaft core 3b of the main shaft 3 by a predetermined eccentricity a. An eccentric shaft 4 having 4b, a tool 5 detachably fixed to the front end side of the eccentric shaft 4, and a rear end side of the main shaft 3 are disposed so as to be integrally rotatable, and the eccentric shaft 4 is driven about its axis 4b. The eccentric shaft motor 6, the speed reduction means 7 disposed between the eccentric shaft 4 and the eccentric shaft motor 6, and the connecting shaft 8 disposed between the eccentric shaft motor 6 and the speed reduction means 7. I have.

  The bearing case 2 is fixed to the movable table 1 on the front end side close to the tool 5. The main shaft 3 has a cylindrical shape, and is concentrically formed on the rear end side of the first main shaft portion 10 and a first main shaft portion 10 rotatably supported in the bearing case 2 via bearings 9 on both front and rear sides thereof. The second main shaft portion 11 is joined, and is rotatable around the shaft core 3b by driving a main shaft motor (not shown) through a transmission mechanism 12 disposed on the rear end side of the first main shaft portion 10. . The transmission mechanism 12 includes a pulley 13 fixed to the first main shaft portion 10 and a belt 14 wound around the pulley 13. The main shaft motor is arranged in parallel with the main shaft 3 and is fixed to the movable table 1.

  The eccentric shaft 4 is parallel to the main shaft 3, and as shown in FIG. 3, the eccentric shaft center 4 a is eccentric from the main shaft center 3 a of the main shaft 3 by a predetermined amount of eccentricity a, and a bearing 16 is provided in the first main shaft portion 10. Is supported so as to be rotatable around the shaft core 4b. The eccentric shaft 4 can be rotated around the shaft core 4 b by driving the eccentric shaft motor 6.

  A tool 5 is detachably attached to the front end of the eccentric shaft 4 via a tool holder 17. The tool 5 has an attachment shaft 18 detachably fixed to the tool holder 17 from the front side, and a blade portion 19 provided on the front end side of the attachment shaft 18, and the eccentric shaft 4 is the origin as shown in FIG. The mounting shaft 18 is configured to be positioned on the main shaft center 3a (= axial core 3b) of the main shaft 3 at the position p1. That is, the eccentric amount of the mounting shaft 18 with respect to the eccentric shaft center 4 a of the eccentric shaft 4 is the same as the eccentric amount a between the main shaft 3 and the eccentric shaft 4.

  An eccentric shaft motor 6, a speed reduction means 7, and a connecting shaft 8 are accommodated in the second main shaft portion 11. As the eccentric shaft motor 6, a stepping motor capable of positioning and holding the stop position is employed. The eccentric shaft motor 6 is fixed in the second main shaft portion 11 of the main shaft 3 on the rear rear end side of the eccentric shaft 4, and the rotating shaft 20 protruding forward is disposed on the shaft core 4 b of the eccentric shaft 4. Has been.

  A wave gear device 21 that is small and has a large reduction ratio is employed as the reduction means 7. As shown in FIGS. 2 and 4, the wave gear device 21 is engaged with an internal gear 22 fixed on the shaft 4 b of the eccentric shaft 4 in the first main shaft portion 10 and the internal gear 22 from the inside. And an elastically deformable thin flat gear 23, an input shaft 24 disposed on the shaft core 4b of the eccentric shaft 4, and a thin bearing 25 fixed to the outer periphery of the input shaft 24 and fitted on the outer peripheral side. And an elliptical eccentric cam 26 slidably in contact with the inner peripheral side of the thin flat gear 23.

  The wave gear device 21 includes a thin flat gear 23 that elastically deforms following the outer periphery of the eccentric cam 26 when the elliptical eccentric cam 26 rotates in conjunction with the rotation of the input shaft 24. The rotation of the eccentric shaft motor 6 is decelerated by utilizing the differential with the perfectly circular internal gear 22 with which the thin flat gear 23 meshes. Incidentally, the reduction ratio of the wave gear device 21 is 1/30 or more.

  The input shaft 24 is connected to the rotary shaft 20 of the eccentric shaft motor 6 through the connecting shaft 8 and the shaft joint 27. The connecting shaft 8 and the shaft joint 27 are arranged on the axis 4 b of the eccentric shaft 4 in the front-rear direction. The connecting shaft 8 is supported at its intermediate portion in the front-rear direction via a bearing 29 by a bearing case 28 between the first main shaft portion 10 and the second main shaft portion 11. The connecting portion 30 of the thin flat gear 23 is detachably fixed to the end surface of the eccentric shaft 4.

  The main shaft 3 is supported on the first main shaft portion 10 side by the bearing case 2, and the rear end portion side of the second main shaft portion 11 is rotatably supported by a support member 32 via a bearing 31. The support member 32 is detachably fixed to the rear end side of the bearing case 2 via a plurality of attachment members 33 in the circumferential direction.

  At the rear end of the second main shaft portion 11 of the main shaft 3, a rotating shaft portion 35 that can rotate integrally with the second main shaft portion 11 is disposed. A coolant introduction port 36 is provided on the rotating shaft portion 35, and the rotating shaft portion 35. A slip ring 37 for supplying power is provided between the support member 32 and the eccentric shaft motor 6.

  The coolant introduction port 36 receives coolant from a coolant supply system (not shown) via a rotary pipe joint (not shown), and from the coolant passage 38 in the rotary shaft portion 35, the second main shaft portion 11 and the first main shaft portion 10. A coolant passage 39, a coolant passage 40 on the axis 4 b of the eccentric shaft 4, and the tool holder 17 are supplied to the machining site on the tool 5 side. In addition, between the main shaft 3 and the eccentric shaft 4, two oil seals 41 for communicating the coolant passages 39 and 40 are provided at a predetermined interval.

  The slip ring 37 includes a rotor 42 fixed to the outer periphery of the rotary shaft portion 35 and a stator 43 fixed to the support member 32 side. The stator 43 is fixed to a bearing press cover 44 that presses the bearing 31, and the bearing press cover 44 is fixed to the support member 32. The stator 43 may be attached to the support member 32 so as not to rotate, and need not be fixed to the support member 32.

  In this tool diameter variable spindle apparatus, as shown in FIG. 3, when the eccentric shaft 4 is at the origin position p <b> 1, the center of the tool 5 coincides with the axis 3 b of the spindle 3. Accordingly, if the eccentric shaft 4 is arranged at the origin position p1, the drilling tool 5 can be mounted and the drilling tool 5 can be mounted and drilling can be performed. It is also possible to perform end milling by attaching an end mill tool 5.

  When changing the tool diameter, the eccentric shaft 4 is rotated about the eccentric shaft center 4 a by the eccentric shaft motor 6 via the connecting shaft 8 and the wave gear device 21. Then, while the eccentric shaft 4 rotates from the origin position p1 to the 180 ° rotation position p5, the tool diameter drawn by the tool 5 around the axis 3b of the main shaft 3 according to the rotation angle of the eccentric shaft 4 is shown in FIG. It can be arbitrarily changed as shown in (E).

  That is, when the eccentric shaft 4 is at the origin position p1, as shown in FIG. 5A, the axis of the tool 5 coincides with the axis 3b of the main shaft 3, so that the tool diameter around the main shaft 3 of the tool 5 is increased. Is the minimum diameter d1 corresponding to the length b (see FIG. 3) from the center of the attachment position of the tool 5 to the cutting edge. Further, at the 180 ° rotation position p5 where the eccentric shaft 4 is rotated 180 ° from the origin position p1, the tool 5 is reversed as shown in FIG. 5E, and the tool diameter of the tool 5 is set to the length b and the eccentric amount a The maximum diameter d5 (= 2a + b) is obtained by adding 2a, which is twice as large.

  Further, when the eccentric shaft 4 rotates to the respective rotation positions p2 to p4 of 45 °, 90 °, and 135 ° between the origin position p1 and the 180 ° rotation position p5, the tool diameter of the tool 5 is changed from FIG. As shown in D), intermediate diameters d2 to d4 between the minimum diameter d1 and the maximum diameter d5 are obtained.

  Therefore, it is possible to perform machining with different tool diameters with one type of tool 5 during boring, etc., and it is not necessary to prepare the tool 5 for each tool diameter, and the number of types of tools 5 to be prepared can be reduced. .

  In particular, in this variable tool diameter spindle device, a wave gear device 21 is interposed between the eccentric shaft motor 6 and the eccentric shaft 4, and a small wave gear device 21 having a large reduction ratio is provided. 6 can be sufficiently decelerated by the wave gear device 21 and transmitted to the eccentric shaft 4. Therefore, the rotation angle of the eccentric shaft motor 6 per unit eccentric amount can be increased, the resolution of the eccentric amount of the tool 5 when changing the tool diameter can be increased, fine adjustment of the eccentric amount, Fine adjustment can be performed easily and with high accuracy.

  Further, since the reduction gear ratio of the wave gear device 21 is large, the load torque is increased, and the eccentric shaft 4 is not rotated by the cutting load applied during machining, and the eccentric amount of the tool 5 is not displaced, and high dimensional accuracy is maintained. be able to. Moreover, since no clamping means for fixing the eccentric shaft 4 is required, the structure can be simplified.

  Further, since the wave gear device 21 having a large reduction ratio is used, it is not necessary to adopt a large-sized motor such as a motor with a speed reducer as the eccentric shaft motor 6, and the wave gear device 21 is changed from the eccentric shaft motor 6. It is possible to reduce the size of the drive transmission system including Therefore, although the eccentric shaft motor 6 and the wave gear device 21 are incorporated in the first main shaft portion 10 and the second main shaft portion 11 constituting the main shaft 3, the diameter of the main shaft 3 can be prevented from being increased. The mechanical rigidity accompanying the reduction in the overall size and weight can be easily promoted.

  That is, when performing boring with the tool 5 or the like, the spindle 3 is rotated about its axis 3b via the transmission mechanism 12 by the spindle motor. At this time, the eccentric shaft motor 6, the wave gear device 21, and the eccentric shaft 4 rotate integrally around the axis 3b of the main shaft 3. However, since the eccentric shaft motor 6 and the wave gear device 21 can be reduced in size, the main shaft 3 The load on the side can be reduced, and the mechanical rigidity is improved.

  Since the wave gear device 21 is disposed in the first main shaft portion 10 and the eccentric shaft motor 6 is disposed in the second main shaft portion 11 detachably joined to the first main shaft portion 10, the eccentric shaft The motor 6 and the wave gear device 21 can be easily assembled. In addition, since the end portion of the second main shaft portion 11 is supported by the support member 32 on the bearing case 2 side via the bearing 31, shaft runout on the second main shaft portion 11 side can also be prevented.

  Further, since the eccentric shaft motor 6 and the wave gear device 21 are in the main shaft 3 and the eccentric shaft motor 6 and the wave gear device 21 are on the shaft core 4 b of the eccentric shaft 4, the eccentric shaft is rotated during the rotation of the main shaft 3. It is also possible to change the tool diameter by rotating the eccentric shaft 4 by the motor 6. Therefore, by changing the tool diameter during machining, it is possible to perform drum-like machining or taper machining with different diameters, and the application can be improved.

If the hole diameter to be machined is known, the rotation angle of the eccentric shaft motor 6 can be obtained from the following calculation formula using the cosine theorem. However, it is assumed that the cutting edge of the tool 5 faces the outside of the eccentric shaft 4 in the radial direction.
Θ = arccos ((a ² + (a + b) ² −r ² / 2a (a + b)) × reduction ratio Θ: rotation angle of the eccentric shaft motor 6 (angle from the origin)
a: Distance between the center of the spindle and the center of the eccentric shaft (Eccentricity)
b: Length from the center of the tool mounting position to the cutting edge r: Radius of the hole to be machined

  If the rotational angle of the eccentric shaft motor 6 is changed in accordance with such a calculation formula, the hole can be drilled with the minimum diameter d1 of the attached tool 5 at the origin position p1, and the maximum diameter d5 at 180 ° from the origin position p1. Hole processing is possible. However, since the cutting edge angle of the tool 5 with respect to the work material changes due to the change of the rotation angle, the amount of eccentricity in actual machining is calculated in consideration of the change in the cutting edge angle. There is a need.

  6 and 7 illustrate a second embodiment of the present invention. In this tool diameter variable spindle apparatus, as shown in FIG. 6, the tool 5 is arranged on the eccentric shaft center 4 a of the eccentric shaft 4 with the shaft center thereof deviating from the main shaft center 3 a of the main shaft 3. Other configurations are the same as those of the first embodiment.

  Thus, even when the tool 5 is arranged on the eccentric shaft center 4a of the eccentric shaft 4, the minimum diameter d1 is obtained when the eccentric shaft 4 is at the origin position p1 shown in FIG. At the 180 ° rotation position p5 shown in (E), the maximum diameter is d5. When the eccentric shaft 4 is at the 45 ° rotation position p2, the 90 ° rotation position p3, and the 135 ° rotation position p4 shown in FIGS. 7B to 7D, the tool diameter of the tool 5 is set to each rotation of the eccentric shaft 4. The intermediate diameters d2 to d4 correspond to the corners.

  Therefore, the tool 5 can be disposed on the axis 4b of the eccentric shaft 4. However, in this case, since the minimum diameter d1 and the maximum diameter d5 are smaller than those in the first embodiment, it is suitable for small-diameter boring.

  As mentioned above, although embodiment of this invention was explained in full detail, this invention is not limited to this embodiment, A various change is possible. For example, although the wave gear device 21 is employed as the speed reduction means 7 in the embodiment, a speed reduction means 7 other than the wave gear device 21, for example, a planetary gear type, a differential type, or the like can be used.

  The eccentric shaft motor 6 is generally a stepping motor, but a servo motor or the like can also be used. Further, when a stepping motor is used as the eccentric shaft motor 6, the rotation angle can be managed by the number of pulses, so that the rotation angle can be easily controlled. However, when another general motor is used for the eccentric shaft motor 6, the rotational shaft 20 is provided with rotational angle detection means such as a pulse encoder, and the eccentric shaft motor is connected via the rotational angle detection means. It is also possible to control the amount of eccentricity of the tool 5 while monitoring the rotation angle of the six rotation shafts 20.

  In the eccentric shaft motor 6, the rotary shaft 20 is disposed on the eccentric shaft center 4 a of the eccentric shaft 4, but the entire center of gravity is preferably on the main shaft center 3 a of the main shaft 3 as much as possible. In the embodiment, the connecting shaft 8 is interposed between the rotating shaft 20 of the eccentric shaft motor 6 and the speed reducing means 7, but the rotating shaft 20 of the eccentric shaft motor 6 is connected to the speed reducing means 7. It is also possible to omit the connecting shaft 8.

  In the first embodiment, the tool 5 is provided so that the eccentric shaft 4 is positioned on the axis 3b of the main shaft 3 when the eccentric shaft 4 is at the origin position p1. In the second embodiment, the axis of the eccentric shaft 4 is provided. Although the tool 5 is provided so as to be positioned on 4b, this tool 5 is positioned on the axis 3b of the main shaft 3 at the origin position p1 and on the axis 4b of the eccentric shaft 4, for example, the axis of the main shaft 3. It is also possible to arrange them between 3b and the axis 4b of the eccentric shaft 4.

  Further, in the embodiment, the eccentric shaft 4 and the speed reducing means 7 are arranged in the first main shaft portion 10, and the eccentric shaft motor 6 is arranged in the second main shaft portion 11 connected to the first main shaft portion 10. The main shaft 3 may be integrated from the eccentric shaft 4 side to the eccentric shaft motor 6 side, and the eccentric shaft 4, the speed reduction means 7, and the eccentric shaft motor 6 may be arranged in the main shaft 3 in the front-rear direction.

3 Spindle 3a Spindle center 3b Shaft core 4 Eccentric shaft 4a Eccentric shaft center 4b Shaft core 5 Tool 6 Eccentric shaft motor 7 Deceleration means 8 Connection shaft 21 Wave gear device 32 Support member 37 Slip ring

Claims (5)

A main shaft, an eccentric shaft having a tool and arranged eccentrically in the main shaft, and an eccentric shaft motor for rotating the eccentric shaft relative to the main shaft; and rotating the eccentric shaft to rotate the tool. In a tool diameter variable spindle device that enables change of the tool diameter around the spindle,
A variable tool diameter spindle device, wherein the eccentric shaft motor is arranged on an axis of the eccentric shaft so as to be rotatable integrally with the spindle. 2. The variable tool diameter spindle device according to claim 1, further comprising a reduction unit that decelerates rotation of the eccentric shaft motor between the eccentric shaft and the eccentric shaft motor. The variable diameter spindle device according to claim 1 or 2, wherein the eccentric shaft motor is provided in the main shaft. The speed reduction means is a wave gear device;
4. The variable tool diameter spindle device according to claim 3, wherein the wave gear device is provided in the spindle. A support member for rotatably supporting the spindle on the eccentric shaft motor side;
5. The tool diameter variable spindle device according to claim 3, wherein a slip ring for supplying power to the eccentric shaft motor is provided between the spindle and the support member.

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