JP6472697B2 - Rotary table with switchable reduction ratio - Google Patents

Description

  The present invention relates to a rotary table that is mounted on a machining center or the like and outputs two systems of driving force from a common output shaft.

As a general workpiece machining process, a workpiece roughing process and a finishing machining process are performed using a lathe or the like. Thereafter, the workpiece is replaced by a machining center or the like, and a cutting process by the machining center or the like is performed. Also, depending on the machining process, the machining center or the like may be changed to a lathe or the like, and it is difficult to avoid the changeover when machining one workpiece.
In such a machining process, the rotary table is mounted on a machining center or the like, and the rotary table is generally used for the purpose of indexing and fixing the mounted workpiece at an arbitrary angle. Has been. As another example of use, there is an application in which a workpiece attached to a rotary table is continuously rotated at a rotational speed (low speed) that can withstand cutting force.
In the cutting process, the rotary table requires high indexing accuracy and a large rotational torque that can withstand the cutting force. Therefore, the rotary table is a worm reducer that uses a worm gear mechanism that combines a worm and a worm wheel, or a roller gear reducer that uses a roller gear cam mechanism that engages a plurality of cam followers arranged radially on the roller gear and output shaft. The built-in mechanism enables high indexing accuracy and large rotational torque.
Further, the resolution of these speed reduction mechanisms can be made higher on the output shaft side than the resolution of the encoder attached to the servo motor or the like. That is, since the rotational position accuracy close to the workpiece can be increased, these reduction mechanisms have become common and have been widely adopted these days.
Further, the conventional rotary table outputs high indexing accuracy and large rotational torque from one system of driving force (such as a motor) to one output shaft (such as a spindle).
Furthermore, since the turntable is mounted on a machining center or the like, a user has always been required to use a turntable with a thin barrel thickness in order to increase the machining area within the determined machining area of the workpiece.
Also, in the machine tool industry, there is a question of how to shorten the tact time (process work time for achieving an equal timing of the production process in manufacturing). It has been developed using various technologies so that it can be shortened in a few seconds.

Japanese Patent Application No. 2014-052878

Therefore, the present applicant has invented the rotary table described in Patent Document 1. According to Patent Document 1, two types of driving force are mounted on a rotary table, and a reduction ratio different from each driving force is output to a common output shaft by using a planetary reduction mechanism, and the reduction ratio is changed. It is possible.
That is, one rotary table can be used for two roles such as high-precision indexing cutting and high-speed rotary cutting.
Therefore, it is not necessary to replace a conventional lathe to a machining center, or from a machining center to a lathe, and the tact time can be greatly reduced.
Further, in Patent Document 1, in order to improve the rotation accuracy, the first ring gear and the first ring gear have a structure that increases the degree of meshing between the planetary reduction mechanism, the first ring gear, and the second ring gear and removes backlash. Each of the ring gears 2 is provided with a preload mechanism so that the preload is adjusted during assembly.
However, since there are two preload mechanisms, it takes much time to assemble. Moreover, since there are many parts, there existed a subject that the lengthening of an apparatus and a manufacturing cost will become high.

  In order to solve the above problems, the present invention is equipped with a two-system driving force on a rotary table, and outputs a reduction ratio different from each driving force to a common output shaft by using a planetary reduction mechanism. An object of the present invention is to provide a rotary table capable of switching the ratio and to reduce the cost by simplifying the preload adjustment work during assembly and reducing the size of the apparatus.

In order to solve the above-described problems, the rotary table of the present invention is a planetary reduction gear in a rotary table that outputs two systems of driving force to different spindles, which are common output shafts, via different reduction gears. The mechanism is structured to be movable in the axial direction, and the first ring gear and the second ring gear can be preloaded simultaneously by adjusting the preload from one direction.
Specifically, the first invention includes a body, a first drive source, a first transmission mechanism that decelerates and transmits a driving force from the first drive source, and the first transmission mechanism. Fixed to the first ring gear, the second drive source, the second transmission mechanism for decelerating and transmitting the driving force from the second drive source, and the second transmission mechanism. A second ring gear, at least two or more planetary reduction mechanisms comprising a gear shaft and a planetary gear meshing with the first ring gear and the second ring gear, and a first driving force by the planetary reduction mechanism. Alternatively, a spindle that transmits the second driving force by further decelerating, a fixing means that fixes the planetary speed reduction mechanism at an arbitrary position of the spindle, and a first pressure that meshes with the planetary speed reduction mechanism with a preload from one direction. Preload that simultaneously increases the degree of meshing between the ring gear and the second ring gear The same number of concave portions as the planetary speed reduction mechanism are formed at equal intervals in the circumferential direction on the outer peripheral surface of the spindle, and the width of the concave portion is formed wider than the gear shaft width in the axial direction, The reduction ratio is switched by transmitting different reduction ratios transmitted from the respective driving forces to a common spindle via a planetary reduction mechanism.

  According to the above configuration, the planetary speed reduction mechanism is movable along the concave portion of the spindle, and the planetary speed reduction mechanism and each ring gear can be preloaded simultaneously by preloading from one direction. In addition, this makes it possible to simplify the assembly work and make the apparatus compact, and to provide a reduction in cost by simplifying the structure.

  According to a second aspect of the invention, the fixing means includes an annular member and a fixing member provided outside the planetary speed reduction mechanism, a locking groove is formed at one end of the gear shaft, and the planetary member includes the planetary member. The same number of penetrating tap holes as the speed reduction mechanism are formed at equal intervals in the circumferential direction, the fixing member is screwed with the tap hole of the annular member, and the lower end surface of the fixing member abuts the locking groove. The planetary speed reduction mechanism is fixed.

  According to the above configuration, the annular member and at least two or more planetary speed reduction mechanisms are evenly contacted by the fixing member, so that the balance can be achieved and the planetary speed reduction mechanism can be fixed.

  The present invention is capable of switching the reduction ratio by mounting two systems of driving forces on the rotary table and transmitting different reduction ratios from the respective driving forces to a common output shaft by using a planetary reduction mechanism. In the rotary table, it is possible to provide cost reduction due to simplification of preload adjustment work during assembly and downsizing of the apparatus.

It is sectional drawing which showed the turntable of embodiment of this invention. It is the figure seen from the arrow A of FIG. 1, and is sectional drawing which notched one part. It is the expanded sectional view seen from the arrow B of FIG.

  The best mode for carrying out the present invention will be described below with reference to the drawings as appropriate. It should be noted that the following description of the preferred embodiments is merely illustrative in nature and is not intended to limit the present invention, its application, or its use.

In the present invention, FIG. 1 is a cross-sectional view of the rotary table of the embodiment, FIG. 2 is a view seen from an arrow A in FIG. 1, a cross-sectional view partly cut away, and FIG. 3 is from an arrow B in FIG. The enlarged sectional views are shown respectively.
As shown in FIGS. 1 to 3, the rotary table 100 capable of switching the reduction ratio according to the present embodiment decelerates the body 1, the motor 10 (first drive source), and the driving force generated from the motor 10. The first transmission mechanism 11 for transmission, the first ring gear 12 fixed to the first transmission mechanism 11, the motor 20 (second drive source), and the driving force generated from the motor 20. A second transmission mechanism 21 that transmits the first transmission gear 21 at a reduced speed, a second ring gear 22 that is fixed to the second transmission mechanism 21, and a planet that meshes with the first ring gear 12 and the second ring gear 22. A reduction mechanism 30, a spindle 2 to which each driving force is further reduced and transmitted by the planetary reduction mechanism 30, and a fixing means 50 that fixes the planetary reduction mechanism 30 at an arbitrary position of the spindle 2 are provided.

The spindle 2 includes a table surface 3 to which a jig or a workpiece can be attached at one end, and is supported on the body 1 by a bearing 13 so as to be rotatable about a rotation axis J.
Further, six concave portions 40 are formed on the outer peripheral surface of the spindle 2 at equal intervals in the circumferential direction.
The recess 40 has a flat slide surface 41 on which a gear shaft, which will be described later, can move, and a guide surface 42 that serves as a guide when moving in parallel with the axial direction of the rotation axis J. Further, the width W of the recess is formed wider than the width W1 of the gear shaft 32 described later in the axial direction, and the depth D is formed to be substantially equal to or greater than the depth D1 of the gear shaft 32.
In this embodiment, six recesses are provided, but at least two recesses may be used.

  The first transmission mechanism 11 includes a worm wheel 11a and a worm shaft 11b. One end side of the worm shaft 11b is pivotally supported on the body 1 through a bearing, while the other end side is A main shaft of the motor 10 is attached. Thereby, the worm shaft 11b can rotate following the rotation of the motor 10.

  The worm wheel 11a has a hollow circular cross-sectional shape, and the outer periphery of the worm wheel 11a and the worm shaft 11b can be engaged with each other. The rotation of the worm shaft 11b causes the worm wheel 11a to transmit a rotational force and reduce the speed. Thus, it can rotate around the rotation axis J.

The planetary reduction mechanism 30 includes a planetary gear 31 and the same number of gear shafts 32 as the planetary gear 31.
The planetary gear 31 has a through-hole at the center, and six planetary gears 31 are provided radially equidistantly with respect to the rotation axis J outside the spindle 2. The plurality of planetary gears 31 are arranged at the same position with respect to the rotation axis J direction. In the present embodiment, the number of planetary gears 31 is six, but at least two planetary gears 31 may be used.

The gear shaft 32 has a T-shaped cross section in which a flange portion 32a projecting radially outward from the outer peripheral surface at one end and a cylindrical portion 32b at the other end are connected to the end surface of the cylindrical portion 32b. Is provided with a locking groove 32c.
The planetary gear 31 is pivotally supported by a bearing through a bearing, and the flange portion 32a at one end is in contact with the slide surface 41 provided on the spindle 2 so as to be movable in the direction of the rotation axis J. On the other hand, the cylindrical portion 32b on the other end side is pressed radially inward by a fixing means 50 described later.
The gear shaft 32 can be translated in the axial direction with the guide surface 42 as a guide.

  The fixing means 50 fixes the planetary reduction mechanism 30 that has been moved to an arbitrary position in the concave portion 40 of the spindle 2 by preload described later.

The fixing means 50 includes an annular member 51 and a set screw 52. On the outer peripheral surface of the annular member 51, the same number of tapped holes 53 as the planetary gear 31 are arranged at equal intervals in the circumferential direction. Is formed.
The set screw 52 includes a male screw portion 52a and a rod-like portion 52b.
The annular member 51 is provided on the outer periphery of the gear shaft 32 with some clearance so as to cover the planetary gear 31 and the gear shaft 32, and a set screw 52 is screwed into the tap hole 53 from the outside. Since the rod-like portion 52b of the screwed set screw 52 is engaged with an engaging groove 32c provided in the gear shaft 32, the set screw 52 presses the gear shaft 32 radially inward.

All six gear shafts 32 are evenly locked and pressed to achieve a balance, and the gear shaft 32 is fixed to the spindle 2.
That is, the planetary reduction mechanism 30 is fixed to the spindle 2.
With such a fixing means 50, the rotary table of this embodiment can reduce the radial and axial spaces.

The first ring gear 12 is pivotally supported on the outer side of the spindle 2 via a bearing so as to be rotatable about a rotation axis J.
The first ring gear 12 has a substantially cylindrical shape, and one end side has a bowl shape toward the outer periphery. The above-mentioned worm wheel 11a is fitted on the substantially cylindrical outer periphery, and is fixed to the flange-shaped side with bolts. On the other hand, a meshing portion 12 a that meshes with the planetary gear 31 is provided on the other end side opposite to the bowl-shaped side.

  On the outer periphery of the meshing part 12a, one or two or more cam followers 12b arranged at equal intervals with respect to the rotation axis J are provided. The plurality of cam followers 12b are arranged at the same position in the rotation axis J direction.

The second transmission mechanism 21 includes a driving pulley 21a, a belt 21b, and a driven pulley 21c that decelerate and transmit the driving force generated from the motor 20.
The driving pulley 21a is fixed to the main shaft of the motor 20, and can rotate following the rotation of the motor 20a. A belt 21b is hung on the outer periphery of the driving pulley 21a.
The driven pulley 21c has a hollow circular cross-sectional shape, and is supported on the outside of the spindle 2 via a bearing so as to be rotatable about the rotation axis J. The driven ring 21c is bolted to the second ring gear 22 with a bolt 23. It is fixed so as to be coaxial with the second ring gear 22. A belt 21b to which the driving force of the driving pulley 21a is transmitted is applied to the outer periphery of the driven pulley 21c.

  The second ring gear 22 has a substantially cylindrical shape, and is supported on the outer side of the spindle 2 so as to be rotatable about the rotation axis J via a bearing. Further, a meshing portion 22 a that meshes with the planetary gear 31 is provided on one end side of the rotating shaft J opposite to the driven pulley 21 c in the axial direction.

  On the outer periphery of the meshing portion 22a, one or two or more cam followers 22b arranged at equal intervals with respect to the rotation axis J are provided. Further, the plurality of cam followers 22b are arranged at the same position with respect to the rotation axis J direction.

A brake mechanism 17 is provided outside the second ring gear 22 to fix and hold the current position with some clearance.
The brake mechanism 17 has a hollow circular cross-sectional shape, and is fixed to the body 1 with bolts 18. The second ring gear 22 stopped by the fluid pressure is fixed and held so that the brake can not be rotated. ing.

  The rotary table 100 includes a preload mechanism 29. The preload mechanism 29 includes a lock nut 29a provided outside the spindle 2. The first ring gear 12 and the second ring that mesh with the planetary reduction mechanism 30 from one direction by adjusting the lock nut 29a. The degree of meshing with the gear 22 is increased at the same time.

Next, a preloading method for increasing the degree of meshing between the first ring gear 12, the planetary gear 31, and the second ring gear 22 during assembly will be described.
When the second ring gear 22 is pressed through the bearing 25 by adjusting the lock nut 29a, the cam follower 22b provided in the second ring gear 22 presses the planetary gear 31.

  At this time, the gear shaft 32 is pressed together with the planetary gear 31 via the bearing, and moves horizontally on the slide surface 41 along the guide surface 42 in parallel with the direction of the rotation axis J, whereby the pressing force is transmitted. The planetary gear 31 presses the cam follower 12 b provided in the first ring gear 12, and the first ring gear 12 is pressed against the spindle 2 via the bearing 15.

That is, when preload is applied to the second ring gear 22 by adjusting the lock nut 29a, the cam follower 22b and the cam follower 12b meshing with the planetary gear 31 are simultaneously preloaded, and the degree of meshing with the planetary gear 31 is increased, and the backlash is zero. Is possible.
After adjusting to an appropriate preload by the lock nut 29a, the gear shaft 32 is pressed evenly inward in the radial direction by a set screw 52 screwed to the annular member 51, so that the gear shaft 32 is moved to the spindle 2 The preload is completed by fixing the balance.

  As described above, according to the rotary table 100 of the present embodiment, the preload adjustment of the planetary speed reduction mechanism, the first ring gear, and the second ring gear can be performed simultaneously from one direction. At times, the preload adjustment work for increasing the degree of meshing and removing the backlash can be easily performed, and the number of parts for preload can be reduced, so that the device can be made compact and the structure is simple. Therefore, it becomes possible to manufacture at a low cost.

The present invention can be used for a rotary table mounted on a machining center, a polishing machine, etc., and as a rotary table for high-precision rotary turning equivalent to a lathe, depending on usage, as a rotary table for high-precision indexing cutting. Can be used.

DESCRIPTION OF SYMBOLS 1 Body 2 Spindle 10, 20 Motor 11 1st transmission mechanism 12 1st ring gear 21 2nd transmission mechanism 22 2nd ring gear 29 Preload mechanism 30 Planetary reduction mechanism 31 Planetary gear 32 Gear shaft 32c Locking groove 40 Recess 50 Fixing means 51 Ring member 52 Set screw 53 Tap hole 100 Rotary table W Recess width

Claims (2)

A body, a first drive source,
A first transmission mechanism for decelerating and transmitting a driving force from the first driving source;
A first ring gear fixed to the first transmission mechanism;
A second drive source;
A second transmission mechanism for decelerating and transmitting the driving force from the second driving source;
A second ring gear fixed to the second transmission mechanism;
At least two or more planetary reduction mechanisms comprising a planetary gear and a gear shaft meshing with the first ring gear and the second ring gear;
A spindle to which the first driving force or the second driving force is further decelerated and transmitted by the planetary reduction mechanism;
Fixing means for fixing the planetary reduction mechanism at an arbitrary position of the spindle;
A preload mechanism that simultaneously increases the degree of meshing between the first ring gear and the second ring gear meshing with the planetary reduction mechanism by preload from one direction,
On the outer peripheral surface of the spindle, the same number of concave portions as the planetary reduction mechanism are formed at equal intervals in the circumferential direction,
The width of the recess is formed wider than the gear shaft width in the axial direction,
A rotary table characterized in that the reduction ratio is switched by transmitting different reduction ratios transmitted from the respective driving forces to a common spindle through the planetary reduction mechanism.
The fixing means comprises an annular member and a fixing member provided outside the planetary reduction mechanism,
A locking groove is formed at one end of the gear shaft,
In the annular member, the same number of penetrating tap holes as the planetary reduction mechanism are formed at equal intervals in the circumferential direction,
The rotary table according to claim 1, wherein the fixing member is screwed into a tap hole of the annular member, and the lower end surface of the fixing member is in contact with the locking groove to fix the planetary reduction mechanism.

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