JP2004066375A - Index table - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an index table, to be attached to the table of a machine tool for indexing work to be processed, which is so structured as to mitigate damage to conveying means when an excessive external force is applied to the table, by absorbing the external force. <P>SOLUTION: This device is an index table consisting of a main body, a revolvable table that is connected to the main body, and conveying means equipped with a wheel and a shaft for conveying the revolution of a motor for turning the table to the table. It is characteristically equipped with an evading mechanism to slightly move the shaft of the conveying means, when an external force, larger than an operational force to be conveyed to the table by the conveying means, is applied to the table. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an indexing table that is attached to a table of a machine tool or the like and performs an indexing operation of a workpiece.
[0002]
[Prior art]
When mounting on a table of a machine tool such as a machining center and processing a workpiece, the tool may be damaged due to a program error of the NC machine, a simple error of mounting a different blade that is not the required blade, or a poor mounting of the workpiece. An accident that collides with the workpiece may occur. Due to such a sudden accident, the indexing table is seriously damaged, and transmission means having a wheel and a shaft for transmitting the rotation of the motor to the table, that is, commonly used worm wheels and worm shafts, hypoid gears Tooth surface damage such as hypoid pinion occurs.
Damage to the transmission means in this indexing table is fatal in a table requiring precise indexing accuracy.
[0003]
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides an indexing table having a structure in which when an excessive external force acts on the table, the table absorbs the external force and reduces damage to the transmission means. The purpose is to:
[0004]
[Means for Solving the Problems]
The present invention is an indexing table comprising: a main body; a rotatable table supported by the main body; and a transmission means having a shaft and a wheel for transmitting rotation of a motor to the table to rotate the table. The indexing table is characterized in that the transmitting means includes an avoiding means for slightly moving the shaft of the transmitting means when an external force greater than the acting force transmitted to the table acts on the table.
[0005]
BEST MODE FOR CARRYING OUT THE INVENTION
[First embodiment]
FIG. 1 is a cross-sectional plan view of a part of an NC indexing table using a hypoid gear as a transmission means.
A table 2 on which a workpiece is mounted is provided on the surface of the main body 1, and is engaged with a transmission means 4 for transmitting the rotational force from the motor 3 to the table 2. The table is supported on the main body 1 through a bearing, and is rotatable with respect to the main body 1.
[0006]
The transmission means 4 is composed of a staggered bevel gear, and includes transmission parts such as a hypoid gear 5 fixed concentrically with the table 2, a hypoid pinion 6 disposed with a fixed offset amount, and a gear for shifting. Consists of The hypoid pinion 6 is inserted into a housing 8 having a pair of bearings 7 for transmitting the rotational force of the motor 3, and the housing 8 is fixed to the main body 1 by bolts 9. The important positioning for fixing is the absolute securing of the offset amount R that can be separated from the center of the hypoid gear 5 by a certain distance. Further, the positioning amount of the depth amount S shown in FIG. It is secure.
[0007]
It is desirable that the variation between the offset amount R and the depth amount S be set within 10 microns, so that the hypoid gear 5 and the hypoid pinion 6 are in normal meshing, and smooth rotation can be obtained.
In the indexing table configured as described above, in order to cope with a sudden large external force generated in the table, the transmitting means 4 is provided with an avoiding means 10 for absorbing a large external force.
FIG. 3 is a partially enlarged view of FIG. 1 and shows a structure for fixing the hypoid pinion 6 to the main body 1.
A housing 8 inserted into the main body 1 and fixed by bolts 9 supports the hypoid pinion 6 by a pair of bearings 7.7. Means 10 are provided.
One of the avoiding means 10 is in contact with the flange 12 of the hypoid pinion 6, and the other is pressed by the lock nut 13 across the pair of bearings 7. That is, the hypoid pinion 6 is fixed while receiving the reaction force of the springs 11, 11 pressed and compressed by the lock nut 13. If the reaction force of the springs 11, 11, a large acting force is applied to the hypoid pinion 6. When working in the axial direction, the hypoid pinion 6 slightly moves in the axial direction. Therefore, when a sudden large external force acts to rotate the hypoid gear 5 while using the indexing table, the acting force generated on the tooth surfaces of the hypoid gear 5 and the hypoid pinion 6 is in the axial direction of the hypoid pinion 6. Absorption and relaxation are caused by the slight movement of the teeth, and damage to the tooth surface can be prevented. However, it should be noted that the reaction force of the springs 11 does not always act on the tooth surfaces of the hypoid gear 5 and the hypoid pinion 6, which is completely different from the purpose of eliminating the conventional backlash. And the configuration is also different.
[0009]
The acting force larger than the reaction force of the above-mentioned springs 11, 11 means, as shown in FIG. 4, when the hypoid pinion 6 is rotated (right rotation R, left rotation L) to rotate the table 2, the hypoid gear 5 is rotated. Is greater than the axial reaction forces FR and FL. That is, it is necessary to tighten the lock nut 13 so that the reaction force of the springs 11 generates a value larger than the reaction force (FR, FL) due to the rotation of the hypoid pinion 6. If the lock nut 13 is excessively tightened, a greater force is required for the fine movement of the hypoid pinion 6, and the amount of the fine movement is also reduced. Therefore, the reaction force of the spring is 1.5 times the size of the reaction forces FR and FL. About twice to twice is desirable.
[0010]
[Second embodiment]
FIG. 5 shows an example in which the position where the avoidance means 10 is provided is changed. In this embodiment, the avoiding means 10 has a structure in which the entire housing 8 supporting the hypoid pinion 6 is slightly moved in the axial direction of the hypoid pinion 6, and the bolt seat surface of the bolt 9 for fixing the housing 8 to the main body 1 and the housing. The springs 11 are assembled between the body 8 and the main body 1 to generate a reaction force on the springs 11 by the tightening force of the bolt 9. Accordingly, when a large acting force acts on the hypoid pinion 6, the hypoid pinion 6 moves slightly in the axial direction together with the housing 8.
As a result, damage to the tooth surfaces of the hypoid gear 5 and the hypoid pinion 6 cannot occur.
It is necessary to tighten the bolt 9 so that by rotating the hypoid gear 5 in the same manner as in the previous embodiment, a reaction force greater than the axial reaction forces FR and FL generated from the hypoid gear 5 is generated in the parallel springs 11.
[0011]
[Third embodiment]
As still another embodiment, as shown in FIG. 6 (all the broken lines are shown by solid lines for easy understanding), which is a partially enlarged view of FIG. Due to the slight movement of the hypoid pinion 6, a large acting force is absorbed and mitigated to prevent damage to the tooth surface.
For this purpose, a structure is adopted in which a counterforce is generated in the parallel springs 11 by a bolt 9 for mounting a housing 8 supporting the hypoid pinion 6 in order to secure the depth S in FIG. Also in the present embodiment, it is necessary to tighten the bolt 9 so that the reaction force of the parallel springs 11 becomes larger than the reaction force in the height direction of the tooth surface generated from the hypoid gear 5 by the rotation of the hypoid pinion 6. .
[0012]
[Other embodiments]
Although all of the above embodiments have been described with reference to the hypoid gear and the hypoid pinion, the same configuration can be applied to the case of a worm wheel and a worm shaft.
Further, a spring suitable for the required reaction force, such as a leaf spring or a coil spring, can be used instead of the spring.
[0013]
【The invention's effect】
According to the configuration described above, even when an excessive acting force acts on the indexing table due to a sudden accident, the cost of maintenance can be greatly reduced without damaging the transmitting means by the action of the avoiding means. .
Further, even if an accident occurs, the indexing table is not damaged, so that the work can be performed with confidence.
[Brief description of the drawings]
FIG. 1 is a plan view in which a part of an indexing table is sectioned.
FIG. 2 is a view taken in the direction of arrow A in FIG. 1;
FIG. 3 is a partially enlarged view of FIG. 1;
FIG. 4 is an explanatory diagram of a reaction force in a part of the transmission means.
FIG. 5 is a partially enlarged view showing a second embodiment.
FIG. 6 is a partially enlarged view showing a third embodiment.
[Explanation of symbols]
1 body,
2 Table 3 Motor 4 Transmission means 5 Hypoid gear 6 Hypoid pinion 7 Bearing 8 Housing 9 Bolt 10 Avoidance means 11 Sara spring 13 Lock nut R Offset amount S Depth amount

Claims (3)

An indexing table comprising a main body, a rotatable table supported by the main body, and a transmission means having a wheel and a shaft for transmitting rotation of a motor to the table to rotate the table, wherein the transmission means comprises: An indexing table comprising an avoiding means for finely moving a shaft of a transmitting means when an external force greater than an acting force transmitted to the table acts on the table. 2. The indexing table according to claim 1, wherein said transmission means is constituted by a hypoid gear. 3. The indexing table according to claim 1, wherein the avoiding means is formed of a salar spring.

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