JP2881674B2 - Feeder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a feed device used for a feed table or the like which is displaced in a state of being balanced by two feed screws and a nut mechanism.

[0002]

2. Description of the Related Art For example, when two ball screws are driven by a single motor and a single rigid body (feed plate) is driven by the two screws, two ball screws are driven due to a mounting error or a pitch error between the two. Lame of the ball screw of the book occurs. But,
Since the feed base is commonly engaged with the two screws, a strong force may act between the two ball screws. If such a force always acts, the life of the nut of the ball screw, the support bearing of the ball screw, the belt, etc. will be adversely affected.

In order to prevent such an adverse effect from occurring, a method has been considered in which a motor is attached to each of two ball screws and the motor is rotated synchronously. However, this requires a large number of mechanical parts. This not only increases the cost but also makes it difficult to control the synchronous operation.

[0004]

According to the present invention, when a single motor drives two feed screw / nut mechanisms to move a rigid body such as a feed table, there is a local pitch error or the like. Another object of the present invention is to improve the life of the power transmission system by eliminating the lameness of the feed screw by balancing the loads acting on the respective feed screw / nut mechanisms.

[0005]

According to the present invention, there is provided a belt which is stretched between pulleys attached to a driving side and a feed shaft side (driven side), respectively, between a pulling side belt and a returning side belt. Utilizing the generated tension difference, the idler pulley that contacts both the pulling side belt and the return side belt is displaced, and using the displacement, the same idler pulley on the other side is displaced, and the feed shafts are displaced. The above-mentioned load is balanced, and the above-mentioned problem is solved by adopting the following configuration.

(1) In a feed device in which two feed screw / nut mechanisms are simultaneously driven by one power device to move one feed table, a driving pulley provided in the power device and the two pulleys are provided. A pair of belts respectively laid between the driven side pulleys provided in the feed screw / nut mechanism, and idler means movably supported at an intermediate position between the respective belts by receiving fluctuations in the tension of the belts; with linking between the idle <br/> error means, when one of the idler means is caused a displacement by the tension fluctuation of the belt, substantially displaces to each other toward or away by the same displacement amount of the other idler means, The load applied to each driven pulley is
And a link mechanism for balancing . (2) The idler means includes floating pulleys provided at positions inside the respective belts so as to be in contact with the inner surfaces of the belts running in opposite directions at both outer peripheries,
The link mechanism includes a pair of swinging rods that swingably support each of the floating pulleys in response to a change in belt tension, and displaces the other floating pulley in substantially the same manner in response to the swinging displacement of one of the floating pulleys. The feed device according to the above (1), comprising a connecting mechanism for connecting the respective swinging rods that swing so as to approach or separate from each other by an amount. (3) The idler means includes a pair of floating pulleys that come into contact with the respective belts from the outside of the belts running in opposite directions, and the link mechanism controls the respective pair of floating pulleys to change the tension of the belts. The floating pulley mounting table which is received and rockably supported, and the other floating pulley mounting table is rocked so as to approach or separate from each other by substantially the same displacement amount corresponding to the rocking displacement of one of the floating pulley mounting blocks. The feeder according to the above (1), which comprises a connecting mechanism for connecting the respective floating pulley mounts.

[0008]

According to the present invention, when the load increases on one feed screw shaft side, the idler means reduces the increased tension due to the difference in tension between the tension and return of the belt with which the idler means contacts. However, in conjunction with this movement, the other idler means is displaced in a direction to increase the load and acts to balance the load applied to both feed shafts. Disappears.

[0009]

FIG. 1 is a schematic diagram showing one embodiment of a feeder according to the present invention, FIG. 2 is a partial schematic diagram showing a modified embodiment thereof, and FIGS. 3 and 4 are schematic diagrams showing another modified embodiment. FIG.

In FIG. 1 showing an embodiment of the present invention, ball screw shafts 5 and 7 which are obliquely upward and away from each other and left and right from a pulley (drive side pulley) 3 attached to one motor shaft 1 are shown. The pulleys (driven pulleys) 9 and 11 are respectively provided in a direction perpendicular to the paper surface.
Are mounted, and the ball screw shafts 5 and 7 are wound around the belt 13 stretched between the driving pulley 3 and the driven pulley 9, respectively, and stretched between the driving pulley 3 and the driven pulley 11. The driving force is transmitted by the belt 15. The feed table is configured to be moved in the direction perpendicular to the paper by a screw / nut mechanism using two ball screw shafts, but is omitted from the drawing because it is a well-known technique.

Further, as shown in FIG.
The L-shaped rod 21 having a swinging fulcrum 19 on the line connecting the motor shaft 1 and the center of the ball screw shaft 5 is supported by the supporting rod 21a extending on the line and is in contact with the inside of the belt 13 and the inside of the running belt. It is arranged to be rotated.

As shown, a support rod 21 having a swing support point 19 is provided.
Since the idler pulley 17 supported by a is in contact with the belt 13 bridged between the drive-side pulley 3 and the driven-side pulley 9 on both sides, the pulley 3 of the motor shaft 1 is clocked as shown by the arrow. When the ball screw shaft 5 is rotated in the same direction, it is rotated in the same direction together with the pulley 9 of the ball screw shaft 5, but when a load is applied to the ball screw shaft 5, the tension on the tension side 13a (right side in the drawing) of the belt 13 increases, and Since the tension on the return side 13b (left side in the drawing) decreases and loosens, the floating pulley 17
Is displaced clockwise about the pivot 19.

Similarly, the driving pulley 3 and the driven pulley 1
The floating pulley 23 has a swinging fulcrum 25 on the inner side of the belt 15 stretched between the two.
7a, the driving pulley 3 and the driven pulley 11
When the pulley 3 of the motor shaft 1 rotates clockwise as shown by the arrow, the pulley 3 is rotated in the same direction together with the pulley 11 of the ball screw shaft 7. When a load is applied to the ball screw shaft 7 , the tension on the tension side 15a (the right side in the drawing) of the belt 15 increases, and the tension on the opposite return side 15b (the left side in the drawing) decreases. It will be displaced clockwise about the swing fulcrum 25.

Therefore, the L-shaped rod 21 on the ball screw shaft 5 side and the L-shaped rod 27 on the ball screw shaft 7 side are connected so that the floating pulleys 17 and 23 which support them are displaced by substantially equal amounts in opposite directions. If a large load is applied to one of the ball screw shafts for some reason, the load will increase the tension on the tension side of the belt, and the floating pulley placed inside the belt will Since the displacement is performed in the direction in which the tension decreases, the load decreases on the drive belt side. For example, when the floating pulley 17 swings clockwise, the floating pulley 23 swings counterclockwise (separates). When the floating pulley 23 swings clockwise, the floating pulley 17 swings (approaches) counterclockwise.

Since the displacement of the idle pulley in the load decreasing direction causes the other idle pulley to move in the direction of increasing the load, the loads on the left and right two ball screw shafts are averaged. Can be.

Further, for example, the tension side 13a of the belt 13
The tension on the right side (in the drawing) increases and the return side on the opposite side
When the tension of 13b (left side in the drawing) decreases, the belt 13 stretched between the driving pulley 3 and the driven pulley 9
13a is displaced so as to be close to a straight line, so that the rotation speed of the driven shaft side pulley 9 also decreases at that time, and it is possible to cope with a sudden increase in load.

The ball screw shaft 5 in the embodiment shown in FIG.
The coupling mechanism between the L-shaped rod 21 of the L-shaped rod 21 and the L-shaped rod 27 of the ball screw shaft 7 will be described.
A long groove 21c and a long groove 27c at the free end 27b of the L-shaped rod 27, respectively.
And a guide groove formed on a bisector of an angle formed by a line connecting the motor shaft 1 and the ball screw shafts 5 and 6 respectively.
If the coupling is performed by the coupling pin 31 that is displaced along 29, the floating pulleys 17 and 23 are displaced by the same amount in the opposite directions to each other.

FIG. 2 shows another configuration of the connecting portion of the two L-shaped rods 21 and 27 of FIG. That is, the pin 31 is implanted at the free end 21b of the L-shaped rod 21 and the free end 27b of the L-shaped
The L-shaped rods 21 and 27 are connected by inserting a pin 31 into the long groove 27c. Then, the floating pulleys 17 and 23 are displaced by substantially equal amounts in directions opposite to each other. Compared to FIG. 1, the displacements of the floating pulleys 17 and 23 are not strictly equal, but they do not pose a practical problem and are structurally simple. Therefore, the configuration of FIG. 2 is more practical and preferable.

The embodiment shown in FIG. 3 is different from the embodiment shown in FIG. 1 in that the idler pulley operates so that the other idler pulley is moved toward or away from the idler pulley by approximately the same amount in response to the displacement of one idler pulley between the idler pulleys. The outer configuration is the same except for the connection mechanism provided between the pulleys. That is, in this embodiment, the free end 21b of the L-shaped rod 21 and the free end 27b of the L-shaped rod 27 are pin-connected with one connecting rod 33, whereby the floating pulley 17, 23 are displaced by substantially equal amounts in directions opposite to each other.

The embodiment shown in FIG. 4 is different from the embodiment shown in FIG. 1 only in the configuration of the floating pulley, and the floating pulley is driven by the difference in tension between the tension side belt and the return side belt which increases as the load increases. Since they are the same in the use of the movement, only the differences in the configuration will be described, and the description of the other points will be omitted.

That is, the floating pulley 17 shown in FIGS.
Is composed of two pulleys 35 and 37 that come into contact with the outside of the belt 13 stretched between the drive-side pulley 3 and the ball screw shaft-side pulley 5, respectively.
The mounting base 39 is pivotally supported by the mounting base 39, and the mounting base 39 moves in a counterclockwise direction in response to a tension change due to a tension difference between the tension side 13a and the return side 13b of the belt 13 due to an increase in load. Rotate.

By the way, similarly, two pulleys 41 and 43 which come into contact with the outside of the belt 15 stretched between the drive side pulley 3 and the ball screw shaft side pulley 11, respectively, are pivotally supported.
It is pivotally supported by a mounting table 45 that is swingably supported at 25,
The mounting base 39 and the mounting base 45 are pin-connected by a connecting rod 47, and the mounting bases are configured to approach or separate from each other according to the rotational displacement.

The floating pulley inscribed in the belt in FIGS. 1, 2 and 3 is composed of two pulleys in the same manner as the pulley in FIG. 4, and each is configured to be inscribed in the belt. Is also good. Further, in this embodiment, the screw rotary type configuration in which the pulley is provided on the ball screw is shown, but it is needless to say that the feed nut may be provided with the pulley and the nut rotary type may be employed. Further, a chain may be used instead of the belt, and the belt described in the claims is a belt-like power transmission means such as a belt and a chain.

[0024]

According to the present invention, when one feed base is driven by two ball screws, the load is not always applied to the two ball screws on average due to mounting errors, pitch errors, and the like. Use of belt tension when idler means overload occurs, which may cause lameness of two ball screws and cause an adverse effect of applying excessive load to nuts, bearings, belts, etc. in the power transmission mechanism Then, the contact state with the belt is moved in the load decreasing direction, and the idler means on the other side is interlocked in accordance with the movement, thereby making it possible to equalize the load at the time of feeding by the two ball screws. Therefore, the life of the feed nut, bearing, belt, etc. of the power transmission system can be extended.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing one embodiment of a feeder according to the present invention.

FIG. 2 is a partial schematic configuration diagram showing a modified example of FIG.

FIG. 3 is a schematic configuration diagram showing still another modified example.

FIG. 4 is a schematic configuration diagram showing still another modified example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Motor shaft 3 Drive pulley 5 Ball screw shaft 7 Ball screw shaft 9 Follower pulley 11 Follower pulley 13 Belt 15 Belt 17 Floating pulley 19 Swing fulcrum 21 L-shaped rod 23 Floating pulley 25 Swing fulcrum 27 L-shaped rod 29 Guide groove 31 Connecting pin 33 Connecting rod 35, 37 Floating pulley 39 Support plate 41, 43 Floating pulley 45 Support plate 47 Connecting rod

Claims (3)

(57) [Claims] 1. A feed device wherein two feed screw / nut mechanisms are simultaneously driven by one power device to move one feed table, wherein a drive pulley provided in the power device and the two feeds are provided. it between the driven pulley provided on the screw-nut unit
A pair of belts stretched and wrapped, idler means variably supported at the intermediate position between the respective belts by receiving a change in the tension of the belts, and connecting the respective idler means; when caused displacement by the tension fluctuation, the other idler means substantially is displaced so that only the same amount of displacement to approach or separate from each other, wherein each driven pulley
A link mechanism for balancing an applied load . 2. The idler means comprises idler pulleys provided at positions inside the respective belts so as to come into contact with inner surfaces of the belts running in opposite directions at both outer peripheries, respectively , and the link mechanism comprises: A pair of swinging rods that swingably support the idler pulley in response to a change in belt tension and move the other idler pulley closer to or away from each other by substantially the same amount of displacement in response to the swinging displacement of one idler pulley. The feed device according to claim 1, wherein the feed device comprises a connecting mechanism that connects the swinging rods that swing as described above. 3. The idler means comprises a pair of floating pulleys which come into contact with the respective belts from the outside of the belts running in opposite directions, and the link mechanism comprises a pair of the respective floating pulleys for tensioning the belts. The floating pulley mount that is swingably supported in response to the fluctuation, and the other floating pulley mount is swung so as to approach or separate from each other by substantially the same amount of displacement in accordance with the swing displacement of one of the floating pulley mounts. The feed device according to claim 1, wherein the feed device is a connecting mechanism that connects the respective floating pulley mounts to be connected.