JPH09309004A - Automatic balancing device for main spindle device with variable tool-diameter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate an occurrence of vibration due to rotational unbalance in order to enhance machining accuracy by offsetting the rotational unbalance, which occurs when both inner and outer main spindles are rotated by means of a counterweight. SOLUTION: In a main spindle device with variable tool-diameter, an inner main spindle 2 whose center is biased against the center of an outer main spindle 3 is installed in a freely rotatable manner within an outer main spindle 3, which is supported by a spindle box 1a in a freely rotatable manner. By relatively rotating these inner and outer main spindles 2, 3 using an eccentric angle controlling means, the diameter of a tool attached to the inner main spindle 2 can be varied freely and continuously. A ring-like counterweight 26 surrounding the inner main spindle 2 is provided on the tip end side of the inner main spindle 2. In addition, a counterweight moving means, which moves the counterweight 26 in the opposite direction to the tool and at a period synchronous with the movement of the tool when the diameter of the tool is varied continuously by relatively rotating the inner and outer main spindles 2, 3, is installed in between the counterweight 26 and the outer main spindle 3. With this, since the rotational unbalance, which occurs when the diameter of the tool is varied, is offset by the counterweight 26, the vibration never occurs even if both inner and outer main spindles are rotated at a high speed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic balance device for a variable tool diameter type spindle device in which a diameter of a tool attached to an inner spindle can be continuously varied by relatively rotating inner and outer spindles that are eccentric to each other. .

[0002]

2. Description of the Related Art Conventionally, as an apparatus of this type, for example, Japanese Utility Model Laid-Open No. 61-109601 (Japanese Utility Model Publication No. 5-6001) and Japanese Patent Laid-Open No. 61-121804 (Japanese Patent Publication No. 5-2560).
No. 2) is publicly known.

The above Japanese Utility Model Publication No. 61-109601 discloses a turning machine for machining a crankshaft,
In the chuck body that clamps the work, slide that adjusts the axis of the chuck body, and in conjunction with this slide,
A balance weight is provided that moves in the opposite direction of the slide movement. Then, when the slide is moved according to the phase of the workpiece to be machined, the balance weight moves in the opposite direction to the slide according to the amount of movement of the slide, and the imbalance that occurs when the chuck body rotates is automatically It is configured to fix.

The method disclosed in Japanese Patent Application Laid-Open No. 61-121804 is a method for balancing the rotational balance of a main shaft device, in which a tool mounted on the inner shaft side is rotated by relatively rotating inner and outer shafts that are eccentric to each other. In a spindle device that allows the diameter to be continuously variable, balance the rotational balance of these when the inner shaft is rotated around the tool, and when the tool and inner shaft are rotated around the inner shaft, The balance of these rotations is balanced, and the balance of these rotations is balanced when the tool and the inner and outer shafts are rotated about the outer shaft. Since the vibration due to the vibration can be prevented, the working effects such as the high speed rotation of the main spindle system can be achieved.

[0005]

However, in the device of the former publication, the imbalance of the slide that moves linearly with respect to the chuck body can be corrected, but the inner and outer main shafts that are eccentric to each other are relatively rotated and attached to the inner main shaft. There is a problem that the imbalance cannot be removed even if it is applied to a machine in which an unbalance occurs due to a turning motion, such as a spindle device that continuously changes the diameter of the tool.

In the method of balancing the rotational balance of the latter publication, in order to balance the rotational balance of the tool and the inner and outer shafts, hollow portions are formed in the inner and outer shafts, and the hollow portions are machined with high precision. Is extremely difficult. In addition, if the machining accuracy of the hollow portion is poor, the imbalance cannot be sufficiently removed, so that vibration occurs during rotation, which causes a problem such as deterioration of the machining accuracy. The present invention has been made to improve such a problem, and a simple automatic balance device for a tool diameter variable type spindle device that automatically corrects a rotational imbalance that occurs when the tool diameter is changed by relatively rotating the inner and outer spindles. It is intended to be provided in various configurations.

[0007]

In order to achieve the above-mentioned object, the invention according to claim 1 is arranged such that an eccentricity is made with respect to the center of the outer main spindle in the outer main spindle rotatably supported by the main spindle box. In the tool diameter variable type spindle device in which the inner spindle is rotatably provided and the inner and outer spindles are relatively rotated by the eccentric angle control means, the diameter of the tool attached to the inner spindle can be continuously varied. A ring-shaped counterweight surrounding the inner spindle is provided on the tip side of the spindle, and the inner and outer spindles are relatively rotated between the counterweight and the outer spindle to continuously change the diameter of the tool. Counterweight moving means for moving the counterweight in the opposite direction to the tool in synchronization with the movement is provided.

When the inner and outer spindles are rotated relative to each other to change the tool diameter with the above structure, the counterweight moves in the opposite direction to the tool moving direction in synchronization with the tool movement by the counterweight moving means as the tool moves. The counterweight cancels out the rotational imbalance that occurs when the inner and outer spindles are rotated, which causes vibration due to rotational imbalance even when the inner and outer spindles are rotated at high speed. As a result, processing accuracy is improved. In addition, since the work can be processed by rotating the inner and outer spindles at high speed, productivity is improved, and since there is no vibration generated due to rotational imbalance, the life of the bearings that support the inner and outer spindles is improved, which results in The durability of the entire spindle device can be improved.

According to a second aspect of the present invention, the counterweight moving means is rotatably supported by a face plate fixed to an outer main shaft and is meshed with a drive gear formed on the inner main shaft, and the face plate. And a eccentric pin which is provided at an eccentric position of the weight support gear and which detachably supports the counterweight.

With the above construction, the counterweight can be reliably moved in the direction opposite to the moving direction of the tool by synchronizing with the relative rotation of the inner spindle, so that it occurs when the tool diameter is changed. It is possible to reliably cancel the rotational imbalance that occurs. Further, since the counterweight moving means can be composed of a plurality of gears, the structure can be provided easily and at low cost.

Further, according to the third aspect of the invention, the counterweight can be exchanged depending on the weight of the tool attached to the inner spindle.

With the above structure, when a tool having a different weight is replaced, the counter weight is replaced with a counter weight corresponding to the weight of the tool, so that the rotational imbalance can be reliably canceled even if the weight of the tool used changes. You can

[0013]

Embodiments of the present invention will be described in detail with reference to the drawings. In the figure, reference numeral 1 denotes a main spindle device main body, and an inner main spindle 2 and an outer main spindle 3 having a double structure are provided in a main spindle box 1a.
Is housed. The inner main spindle 2 is eccentrically displaced by ε with respect to the axis of the outer main spindle 3, and is rotatably accommodated in the outer main spindle 3. The tip of the inner main spindle 2 has the same amount as the eccentricity ε. Eccentric and tapered tool mounting hole 2a
Are formed.

Both ends of the outer main shaft 3 are rotatably supported by the main spindle box 1a via bearings 4. On both sides of the outer main shaft 3, at positions facing each other with the outer main shaft 3 interposed therebetween. For example, a pair of ball screw shafts 5 are provided so as to be parallel to the outer main shaft 3. Both ends of these ball screw shafts 5 are rotatably supported by the spindle box 1a via bearings 6, and gears 7 are fixed to one end of each ball screw shaft 5. A synchronous gear 8 is meshed with these gears 7.

The synchronous gear 8 is a ring gear, and is rotatably supported on the spindle box 1a side via a metal bearing 1b. The synchronous gears 8 cause the ball screw shafts 5 to rotate synchronously. In addition, a tool diameter changing drive source (not shown) composed of a servomotor is connected to one end side of one ball screw shaft 5, and each ball screw shaft 5 is connected by this tool diameter changing drive source. Are to be rotated synchronously.

On the other hand, a shifter 1 is attached to each of the ball screw shafts 5 described above.
The ball nut 11 provided at 0 is screwed. The shifter 10 has an annular shape and is provided so as to surround the periphery of the outer main shaft 3, and is movable in the axial direction of the outer main shaft 3 by synchronously rotating the ball screw shafts 5. . A ring-shaped holder 13 is rotatably supported on the inner peripheral portion of the shifter 10 via a bearing 12, and the inner peripheral portion of the holder 13 has inner and outer main shafts 2, 2.
There are provided a tool diameter changing twist key 14 and a backlash removing twist key 15 which are opposed to each other with 3 in between.

The tool diameter changing twist key 14 and the backlash removing twist key 15 are slidably fitted in guide grooves 3a, 3b formed in the axial direction of the outer main shaft 3, respectively, and together with the shifter 10. Inner and outer spindles 2, 3
The tool-variable twist key 14 is detachably attached to the holder 13 by a fastener 16 while being movable in the axial direction.

The twist key 15 for removing the backlash
Is supported by a guide pin 18 having a head portion 18a fixed to a holder 13 so as to be parallel to the axes of the inner and outer main shafts 2 and 3, and is movable in the axial direction of the inner and outer main shafts 2 and 3. A spring chamber 15b is formed in the spring chamber 15b and is biased to the right by a biasing means 19 such as a compression spring housed in the spring chamber 15b. Then, the twist key 14 for changing the tool diameter and the twist key 15 for removing the backlash.
The twist key portions 14a and 15a shown in FIGS. 4 and 5 projecting from the inner peripheral surface of the shaft are engaged with the two twist key grooves 2b and 2c formed on the outer peripheral surface of the inner main shaft 2, respectively.

As shown in FIG. 3, the twist key grooves 2b, 2c are formed in a spiral shape on the outer peripheral surface of the inner main shaft 2 with a phase difference of 180 °.
The above-mentioned twist key portions 14a and 15a having twist tooth surfaces in which the shapes of these grooves are transferred are slidably fitted in 2c, and at the same time, in the tool diameter changing twist key 14 fixed to the holder 13 side. On the other hand, since the backlash removing twist key 15 is biased in the axial direction of the inner and outer main shafts 2 and 3 by the biasing means 19, the backlash generated between the tool diameter varying twist key 14 and the twist key groove 2b is thereby caused. The rush can be removed.

The twist angle of each of the twist key grooves 2b and 2c is set in the range of 0 to 45 °, and the sliding surfaces of the twist keys 14 and 15 and the twist key grooves 2b and 2c are resistant to wear. In order to improve the performance, it is possible to maintain stable positioning accuracy for a long period of time by performing high-precision finishing processing by grinding processing after performing heat treatment such as nitriding treatment on each sliding surface. It has become.

It should be noted that each of the twist keys 14 and 15 has a structure shown in FIG.
As shown in FIGS. 2, 4 and 5, oil supply holes 14b and 15c are formed, and lubricating oil is applied to the sliding surfaces of the respective twist keys 14 and 15 and the twist key grooves 2b and 2c from these oil supply holes 14b and 15c. Is being refueled.

On the other hand, an automatic balancing device 22 is provided at the front end of the outer main spindle 3. The automatic balance device 2
2 has a case 22a attached to the front surface of the spindle box 1a, as shown in FIGS. Case 2 above
The front surface of 2a is opened, and the cover 22b is opened in this opening.
Is detachably attached, and the case 22 described above is attached.
A disk-shaped face plate 23 fixed to the front end surface of the outer main shaft 3 is accommodated in a.

A circular hole 23a through which the inner main shaft 2 penetrates is opened in the center of the face plate 23, and a pair of weight support gears 24 and a pair of weight support gears 24 are provided on the front face of the face plate 23 so as to face each other with the center therebetween. The weight support member 25 is provided. The weight support gear 24 and the weight support member 25 are rotatably supported at their centers by support shafts 24a, 25a provided at equal intervals in the circumferential direction of the face plate 23, and the weight support gear 24 and the weight support member 25 are also supported. Eccentric pins 24b and 25b are provided at eccentric positions of the support member 25, and ring-shaped counterweights 26 are detachably supported on the eccentric pins 24b and 25b, respectively. The counter weight 26 is shown in FIG.
And, as shown in FIG. 6, it is provided so as to surround the inner main shaft 2 loosely, and has a function of canceling the rotational imbalance that occurs when the inner and outer main shafts 2 and 3 are relatively rotated by the action described later. ing.

Further, each weight support gear 24 has a large gear 2
7a and the small gear 27b are coaxially meshed with the intermediate gear 27 on the small gear 27b side. Each of the intermediate gears 27 is rotatably supported by the face plate 23 by a support shaft 27c, and a large gear 27a of each of the intermediate gears 27 has an inner main shaft 2
Are meshed with the drive gears 2d formed on the outer peripheral surface of each of the intermediate gears 27a and 27b, respectively, in response to the rotation of the drive gears 2d.
Are rotated in the same direction.

On the other hand, a gear 3 is provided at the base end of the inner main shaft 2.
3 is fixed, and a ring gear 34a formed on the inner peripheral surface of one end side of the gear cylinder 34 is meshed with the gear 33. The inner periphery of the gear cylinder 34 is rotatably supported by a support cylinder 36 via a bearing 35, and the gear cylinder 3
The outer peripheral portions on both end sides of No. 4 have low speed gears 34b having different numbers of teeth.
And a high speed gear 34c are formed.
b and 34c are selectively meshed with a drive gear of a main shaft drive source (not shown).

Next, the operation of the tool radius variable type spindle device configured as described above will be described. When the work is machined by using the spindle device, the tool T is attached to the tool mounting hole 2a of the inner spindle 2. The rotation speed suitable for the tool T is set to the low speed gear 34b.
Alternatively, the inner main shaft 2 is rotated via the gear 33 by a main shaft drive source (not shown) selected from the high speed gear 34c. As a result, the outer spindle 3 coupled via the tool diameter changing twist key 14 and the backlash removing twist key 15 is simultaneously rotated, and the tool T attached to the inner spindle 2 enables machining such as boring. You can do it.

When the inner diameter of the work to be machined is changed and the tool diameter is changed, one of the ball screw shafts 5 is rotated by the tool diameter changing drive source. As a result, since the ball screw shafts 5 synchronized with each other are simultaneously rotated in the same direction by the synchronous gears 8, the shifters 10 screwed onto the ball screw shafts 5 via the ball nuts 11 move along the ball screw shafts 5. And the tool diameter changing twist key 14 and the backlash removing twist key 15 attached to the shifter 10 are guided in the guide grooves 3a and 3b of the outer main spindle 3 and moved in the axial direction of the outer main spindle 3. . By the movement of the twist key 14 for varying the tool diameter, the inner spindle 2 with which the twist key portion 14a of the twist key 14 for varying the tool diameter is engaged is rotated in the outer spindle 3.

That is, as the inner main spindle 2 and the outer main spindle 3 are relatively rotated by the tool diameter changing twist key 14 and the twist key groove 2b engaging with the tool key, the center of the inner spindle 2 is set to 0 as shown in FIG. ₃ , when the center of the outer main spindle 3 (center of the tool) is 0 ₂ , the center 0 ₃ of the inner main spindle 2 moves to the position of T ₂ depending on the relative rotation angle θ. The diameter of the tool T is changed from R ₁ to R ₂ by controlling the relative rotation angle θ by the source.
It becomes possible to change continuously.

When the inner main shaft 2 is rotated leftward, for example, the intermediate gear 27 meshing with the drive gear 2d of the inner main shaft 2 is rotated in the same direction (rightward in FIG. 6).
Each weight support gear 24 meshed with the small gear 27b of the intermediate gear 27 is rotated leftward. As a result, the eccentric pin 24b provided on the weight support gear 24 is attached to the support shaft 24.
Since it rotates leftward about a, the eccentric pins 24b, 2 of each weight support gear 24 and each weight support member 25 are rotated.
As shown in FIG. 7, the center of the counterweight 26 supported by 5b moves in the direction opposite to the trajectory of the tool T by the same amount W as the tool T.
Is only moved to cancel the rotational imbalance caused by the movement of the tool T.

That is, when the tool diameter is continuously changed by relatively rotating the inner and outer spindles 2 and 3, the counterweight 2
6 moves the same amount W in the direction opposite to the moving direction of the tool T,
In order to offset the rotational imbalance due to the change in tool diameter,
Even if the tool diameter is arbitrarily changed, it is possible to reliably prevent vibration or the like from occurring due to rotational imbalance during processing.

The tool T detachably attached to the inner spindle 2 may have a different weight when it is replaced according to the size of the workpiece to be machined and the machining content. Tool T
If the weight changes, the amount of rotational imbalance generated when the inner and outer main shafts 2, 3 are rotated also changes, and therefore the counterweight 26 having the same weight cannot sufficiently offset the rotational imbalance.

In order to eliminate such a problem, the tool T
When a plurality of types of counterweights 26 having different weights are prepared and the tool T is replaced, the counterweight 26 having a weight corresponding to the weight of the tool T is selected, and the counterweight 26 is also replaced at the time of tool replacement. By doing so, even if the weight of the tool T used changes, the rotational imbalance can be reliably canceled out.

Further, in the above-described embodiment, the twist key groove 2b with which the tool diameter changing twist key 14 is engaged and the key groove 2c with which the backlash removing twist key 15 is engaged are formed in a single line, respectively. A twist key groove 2b that is formed by a strip or engages with the twist key 14 for varying the tool diameter
Only a plurality of lines may be formed. Further, by providing a plurality of the twist keys 14 and 15 and the twist key grooves 2b and 2c, the reaction force at the time of converting the linear motion of the twist key 14 into the rotational motion is dispersed to the twist keys 14, so that the twist keys 14 It is possible to prevent the sliding surface of 14 and the twisted key groove 2b from having a low surface pressure and to wear the sliding surface early.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a tool shaft variable type spindle device provided with an automatic balancing device according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a detailed view of a twist key groove formed on the outer peripheral surface of the inner main shaft and a twist key engaged with the twist key groove.

FIG. 4 (a) is a front view of a twist key for varying the tool diameter. (B) It is an arrow line view from the B direction of (a) of FIG.

FIG. 5 (a) is a front view of the twist key for removing backlash. (B) It is an arrow view from the C direction of (a) of FIG.

6 is a view from the direction of the arrow D in FIG.

FIG. 7 is an operation explanatory view of a tool-axis variable type spindle device provided with the automatic balancing device according to the embodiment of the present invention.

[Explanation of symbols]

1a ... Spindle box, 2 ... Inner spindle, 2d ... Drive gear, 3 ... Outer spindle, 23 ... Face plate, 24 ... Weight support gear, 24b
... eccentric pin, 26 ... counterweight, 27 ... intermediate gear, T ... tool.

Claims (3)

[Claims] 1. An inner main spindle 2 is rotatably provided in an outer main spindle 3 rotatably supported by a main spindle box 1a so as to be eccentric with respect to the center of the outer main spindle 3, and these inner and outer main spindles 2, 3 are eccentric. In a tool diameter variable type spindle device capable of continuously varying the diameter of the tool T attached to the inner spindle 2 by rotating the inner spindle 2 relative to the inner spindle 2, the inner spindle 2 is surrounded by the tip side of the inner spindle 2. A ring-shaped counterweight 26 is provided, and when the diameter of the tool T is continuously varied by relatively rotating the inner and outer spindles 2 and 3 between the counterweight 26 and the outer spindle 3, the tool T is moved. An automatic balancer for a variable tool diameter type spindle device, comprising counterweight moving means for moving the counterweight 26 in the opposite direction to the tool T synchronously. 2. An intermediate gear 27, which is rotatably supported by a face plate 23 fixed to the outer main shaft 3 and meshes with a drive gear 2d formed on the inner main shaft 2, and the face plate 23. The above-mentioned intermediate gear 2 which is supported
7. The variable tool diameter according to claim 1, comprising a weight support gear 24 meshing with the gear 7, and an eccentric pin 24b provided at an eccentric position of the weight support gear 24 and detachably supporting the counterweight 26. Automatic balance device for mold spindle device. 3. The automatic balancing apparatus for a variable tool diameter type spindle device according to claim 1, wherein the counterweight 26 is replaceable according to the weight of the tool T attached to the inner spindle 2.