JPH09324843A - Fine/coarse/motion ball screw and its unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To execute coarse and fine sending by screwing a ball screw nut through a ball in the ball screw groove of a ball screw nut-cum-ball screw shaft, which is screwed in a ball screw shaft in which a ball screw groove is formed in its periphery and a screw groove and in which a ball screw groove is formed in its periphery. SOLUTION: When a coarse motion side ball screw shaft 43 is rotated by a motor 45, a ball; screw nut 44 is linearly moved by a detent mechanism 56 without being rotated together with the ball screw shaft 43, and a fine motion side ball screw shaft 47 and a nut 50 are also linearly moved accompanied by the movement of the balls crew nut 44, and a table 48 fixed to a supporting body 49 for rotatively supporting a nut 50 is coarsely sent equivalent to the lead of the coarse motion side ball screw nut 44. While, when the nut 50 is rotated by a fine motion side motor 51, the ball screw nut 44 is linearly moved by the ball screw shaft 47, and the table 48 fixed to the supporting body 49 for rotatively supporting the nut 50 is finely sent equivalent to the lend of the screw shaft 47. Hereby, it can be executed from super low speed sending to super high speed sending.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coarse movement fine movement ball screw and a unit thereof which can be used when it is desired to perform coarse movement feed and fine movement feed on the same table.

[0002]

2. Description of the Related Art FIGS. 4, 5, and 6 are, for example, machine tools,
It shows each ball screw unit that feeds a table such as a measuring instrument on one axis.

In the ball screw unit shown in FIG. 4, a ball screw nut 3 is fixed to a table 1 via a bracket 2 and a support body such as a pair of pillow blocks is fixed to the ball screw nut 3 on a base 4. The ball screw shaft 6 rotatably supported by 5 has a plurality of balls (not shown).
A drive motor 7 which is screwed through and is fixed to the ball screw shaft 6 on the base 4 is connected through a coupling 8. In this ball screw unit, when the drive motor 7 rotates the ball screw shaft 6 via the coupling 8, the rotational movement is converted into a linear thrust by the ball screw nut 3, and the bracket 2 is attached to the ball screw nut 3. The fixed table 1 is linearly moved via the.

In the ball screw unit shown in FIG. 5, a ball screw shaft 13 is fixed to a table 11 via a pair of brackets 12, and a base 14 is attached to the ball screw shaft 13.
A ball screw nut 16 rotatably supported by a support body 15 such as a pillow block fixed to the above is screwed through a plurality of balls (not shown), and the ball screw nut 1
A drive motor 17 fixed on the base 14 is connected to the drive shaft 6 via a power transmission mechanism 18. In this ball screw unit, when the drive motor 17 rotates the ball screw nut 16 via the power transmission mechanism 18, the rotational movement is converted into a linear thrust by the ball screw shaft 13, and the ball screw shaft 13 receives a pair of thrusts. The table 11 fixed via the bracket 12 is linearly moved.

The ball screw unit shown in FIG. 6 uses a feed shaft in which a ball spline shaft 21 and two ball screw shafts 22 and 23 having a slight lead difference are integrally formed on one axis. A ball spline nut 26, which is rotatably supported by a support 25 such as a pillow block fixed to a base 24 of the base 21, is screwed through a plurality of balls (not shown), and the ball spline nut 26 is attached to the base. A drive motor 27 fixed on 24 is connected via a power transmission mechanism 28, and a ball screw nut 30 fixed on a block 29 fixed on a base 24 on one ball screw shaft 22 has a plurality of ball screw nuts 30. (Not shown), and the other ball screw shaft 23 is mounted on the table 31 by the bracket 3
The ball screw nut 33 fixed via 2 is screwed through a plurality of balls (not shown). In this ball screw unit, the drive motor 27 drives the power transmission mechanism 2
When the ball spline shaft 21 is rotated through 8, the ball screw shaft 22 is linearly moved by the ball screw nut 30 while being rotated, and the ball screw shaft 23 is also linearly moved while being rotated by the ball screw 23. The screw nut 33 linearly moves in the direction opposite to the ball screw shaft 23, and the table 31 fixed to the ball screw nut 33 via the bracket 32 is attached to the two ball screw shafts 2.
Fine feed is performed corresponding to the lead difference of 2,23. Further, when the ball screw nut 30 is removed from the block 29 fixed on the base 24 and rotates together with the ball screw shaft 22, the drive motor 27 rotates the ball spline shaft 21 via the power transmission mechanism 28. The two ball screw shafts 22 and 23 rotate without linear movement, and accordingly, the ball screw 23 also linearly moves the ball screw nut 33, and the table 31 fixed to the ball screw nut 33 via the bracket 32 is rotated. Coarse motion feed is performed corresponding to the lead of the screw shaft 22.

[0006]

In each of the ball screw units shown in FIGS. 4 and 5, the drive motor 7,
Coarse feed and fine feed are controlled by changing the number of revolutions of 17. Therefore, if the leads of the ball screw shafts 6 and 13 are set to be large with emphasis on coarse feed, the resolution during fine feed will deteriorate. If the leads of the ball screw shafts 6 and 13 are set to be small with emphasis on fine movement feed, the number of rotations of the ball screw shafts 6 and 13 must be increased during coarse movement feed. Problems such as breakage occur.

Further, in the ball screw unit shown in FIG. 6, the ball screw 23 linearly moves while rotating, and the ball screw 23 causes the ball screw nut 3 to move.
The linear movement of 3 in the direction opposite to the ball screw shaft 23 enables the fine movement of the table 31. Therefore, the ball spline shaft 21 and the ball screw shaft 22 are required even though only the ball screw shaft 23 is originally effective as a stroke, and the entire device has a structure that is long in the axial direction, which is also costly. It will be very expensive. Further, during the coarse feed, a conversion mechanism having a structure in which the ball screw nut 30 is removed from the block 29 fixed on the base 24 and rotated together with the ball screw shaft 22 is required, and the structure of the entire apparatus is complicated. It becomes a thing.

Therefore, an object of the present invention is to enable fine movement feed which does not impair resolution and coarse movement feed which does not cause problems such as critical speed and breakage of the circulation portion, and is compact and
(EN) Provided are a coarse movement fine movement ball screw having a simple structure and its unit.

[0009]

In order to achieve the above-mentioned object, the present invention provides a ball screw shaft having a ball screw groove formed on the outer periphery thereof, and a ball screw groove of the ball screw shaft screwed through a plurality of balls. A ball screw nut / ball screw shaft having a ball screw groove formed on the outer periphery thereof, and a ball screw nut screwed into the ball screw groove of the ball screw nut / ball screw shaft through a plurality of balls. And a ball screw shaft rotatably supported by a pair of supports and having a ball screw groove formed on the outer periphery, and a plurality of balls in the ball screw groove of the ball screw shaft. Of the ball screw nut and ball screw shaft, which are screwed together via a ball screw nut and a ball screw groove is formed on the outer periphery of the ball screw groove, and an appropriate anti-rotation mechanism is provided at an arbitrary position. A ball screw nut screwed through a plurality of balls into a ball screw groove, a driving unit that rotationally drives the ball screw shaft, and another driving unit that rotationally drives the ball screw nut. Provided is a characteristic coarse-motion fine-motion ball screw unit.

According to the present invention, the ball screw shaft, the ball screw nut / ball screw shaft, the ball screw nut / ball screw shaft and the ball screw nut constitute two ball screws, each of which is separately controlled to perform coarse movement. I made a slight movement.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows the overall construction of a unit using the coarse / fine movement ball screw of this embodiment.

In this coarse movement / fine movement ball screw unit, a coarse movement side ball screw shaft 43 is rotatably supported on a support body 42 such as a pair of pillow blocks fixed on a base 41.
A coarse movement side ball screw nut 44 is screwed onto the coarse movement side ball screw shaft 43 through a plurality of balls (not shown), and a coarse movement side ball screw nut 43 is fixed to the coarse movement side ball screw shaft 43 on the base 41. The driving side motor 45 is connected via a coupling 46.

As shown in FIG. 2, the coarse movement side ball screw nut 44 is integrally formed with a fine movement side ball screw shaft 47 in which a fine movement ball screw groove is formed on the outer periphery on one axis. A fine movement side ball screw nut 50, which is rotatably supported by a support body 49 such as a pillow block fixed to a table 48 on a shaft 47, is screwed through a plurality of balls (not shown), and a fine movement side ball. A fine movement side motor 51 fixed to the table 48 is connected to the screw nut 50 via a power transmission mechanism 52.

Further, the coarse movement side ball screw nut 44 includes
For example, as shown in FIGS. 1 and 3, when a cam follower 54 rotatably attached to the lower end of a pin 53 fixed to the coarse movement side ball screw nut 44 is fitted into a guide groove 55 formed in the base 41, A stop mechanism 56 is provided, and the rotation stop mechanism 56 does not rotate together with the coarse movement side ball screw shaft 43.

In the above structure, when the coarse movement side motor 45 rotates the coarse movement side ball screw shaft 43 through the coupling 46, the coarse movement side ball screw nut 44 is rotated by the rotation stopping mechanism 56. Since it does not rotate with the shaft 43, the coarse-movement-side ball screw nut 44 moves linearly by the coarse-movement-side ball screw shaft 43, and along with this, the fine-movement-side ball screw shaft 47 and the fine-movement-side ball screw nut 50 also move linearly. The table 48 fixed to a support body 49 in which the side ball screw nut 50 is rotatably supported is fed by coarse movement corresponding to the lead of the coarse movement side ball screw nut 44.

On the other hand, when the fine movement side ball screw nut 50 is rotated by the fine movement side motor 51 via the power transmission mechanism 52, the fine movement side ball screw nut 50 rotates and moves straight by the fine movement side ball screw shaft 47. The table 48, which is fixed to the support body 49 on which the fine-movement-side ball screw nut 50 is rotatably supported, is fine-moved corresponding to the lead of the fine-movement-side ball screw shaft 47.

In the coarse-motion / fine-motion ball screw unit of the present embodiment, the coarse-motion feed achieves high-speed feed at a low rotational speed. Therefore, the lead of the coarse-motion side ball screw shaft 43 is set large, and the fine-motion feed has a high resolution. In order to ensure this, the lead of the fine movement side ball screw shaft 47 is set small. Now, assuming that the lead of the coarse movement side ball screw shaft 43 is set to 40 mm and the lead of the fine movement side ball screw shaft 47 is set to 2 mm, one rotation of the coarse movement side ball screw shaft 43 can perform a coarse feed of 40 mm. ,
Fine rotation of 2 mm is possible with one rotation of the fine movement side ball screw shaft 47. Accordingly, after the coarse movement side motor 45 rotates the coarse movement side ball screw shaft 43 to perform high-speed positioning, the fine movement side motor 51 rotates the fine movement side ball screw nut 50 to perform fine positioning. . in this way,
If fine positioning is performed after high-speed positioning, positioning can be performed in a short time without impairing resolution.
The coarse movement feed and the fine movement feed may be performed separately or simultaneously, and the ball screw grooves of the coarse movement side ball screw shaft 43 and the fine movement side ball screw shaft 47 may be wound in the same direction or in different directions.

Various use examples can be expected by arbitrarily changing the combination of leads of the coarse movement side ball screw shaft 43 and the fine movement side ball screw shaft 47.

For example, the lead of the coarse movement side ball screw shaft 43 is 20 mm and the lead of the fine movement side ball screw shaft 47 is 16 mm.
If it is set to, and it is controlled so as to proceed in the same direction, it has the same effect as a ball screw with a lead 36 mm,
72m / min if rotated at 2000rpm
It enables ultra-high-speed feed and solves problems such as critical speed that cannot be realized with a single ball screw.

When controlled so as to move in the opposite directions, the ball screw having the lead of 4 mm plays the same role.

Further, the coarse movement side ball screw shaft 43 is set to 150.
0 rpm, fine adjustment side ball screw nut 50 at 1870 rp
If they are rotated at m and controlled so as to travel in the opposite directions, respectively, an ultra-low speed feed of 0.08 m / min can be realized.

As an example of an ultra-low speed feed other than the above, it can be realized by providing a slight lead difference between the coarse movement side ball screw shaft 43 and the fine movement side ball screw shaft 47. For example, if the lead of the coarse movement side ball screw shaft 43 is set to 5 mm and the lead of the fine movement side ball screw shaft 47 is set to 4.8 mm, and control is performed so as to proceed in the opposite directions, ultra-low speed feed of 0.2 mm / min is possible. Is.

Although the above description has been made on the case where the leads of the coarse movement side ball screw shaft 43 and the fine movement side ball screw shaft 47 are different, the leads of the coarse movement side ball screw shaft 43 and the fine movement side ball screw shaft 47 are the same. Even if it is, if the coarse-movement-side ball screw shaft 43 and the fine-movement-side ball screw shaft 47 are rotated with a slight rotational speed difference and controlled so as to proceed in the same direction, ultra-high-speed feed is possible. Ultra-low speed feed is possible by controlling each to go in the opposite direction.

[0025]

As described above, according to the present invention,
Since a ball screw groove was machined on the nut outer circumference of one ball screw and the nut outer circumference of one ball screw was used as the screw shaft of another ball screw, the entire device has a structure that is short in the axial direction. It can contribute to downsizing and cost reduction. Also, one ball screw is rotated,
The other ball screw is made to rotate the nut, and each is separately controlled to perform coarse and fine movements. Therefore, the resolution can be secured by setting the lead of the fine movement side ball screw small, and the coarse movement side ball screw can be secured. By arbitrarily combining the lead of the fine movement side ball screw and the ball screw groove winding direction, it is possible to feed from ultra-low speed to ultra-high speed. .

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a unit using a coarse-motion fine-motion ball screw of the present invention.

FIG. 2 is a sectional view of a member in which a coarse movement side ball screw nut and a fine movement side ball screw shaft are machined on one axis.

FIG. 3 is a perspective view of a main part of an example of a rotation stopping mechanism.

FIG. 4 is an overall configuration diagram of a conventional ball screw unit.

FIG. 5 is an overall configuration diagram of another conventional ball screw unit.

FIG. 6 is an overall configuration diagram of still another conventional ball screw unit.

[Explanation of symbols]

 41 base 42 support 43 coarse movement side ball screw shaft 44 coarse movement side ball screw nut 45 coarse movement side motor 46 coupling 47 fine movement side ball screw shaft 48 table 49 support 50 fine movement side ball screw nut 51 fine movement side motor 52 power Transmission mechanism 53 Pin 54 Cam follower 55 Guide groove 56 Anti-rotation mechanism

Claims (7)

[Claims] 1. A ball screw shaft having a ball screw groove formed on the outer periphery thereof, and a ball screw nut having a ball screw groove formed on the outer periphery thereof, which is screwed into the ball screw groove of the ball screw shaft through a plurality of balls. A coarse-motion fine-motion ball screw comprising a ball screw shaft and a ball screw nut screwed into a ball screw groove of the ball screw nut and the ball screw shaft via a plurality of balls. 2. A ball screw shaft rotatably supported by a pair of supports and having a ball screw groove formed on the outer periphery thereof, and a ball screw shaft of the ball screw shaft screwed through a plurality of balls to form an outer periphery thereof. A ball screw groove which is formed with a ball screw groove and which is provided with an appropriate anti-rotation mechanism at an arbitrary position, and a plurality of balls are inserted in the ball screw groove of the ball screw nut and the ball screw shaft. A coarse-motion fine-motion ball screw unit comprising: a ball screw nut screwed together; a driving unit that rotationally drives the ball screw shaft; and another driving unit that rotationally drives the ball screw nut. 3. A coarse movement according to claim 2, wherein a pair of supports for rotatably supporting the ball screw shaft are fixed to a fixed side, and the ball screw nut is rotatably supported on a moving side. Fine movement ball screw unit. 4. A coarse movement according to claim 2, wherein a pair of supports that rotatably support the ball screw shaft are fixed to a moving side, and the ball screw nut is rotatably supported to a fixed side. Fine movement ball screw unit. 5. The coarse / fine adjustment ball screw unit according to claim 2, wherein the ball screw shaft and the ball screw nut / ball screw shaft are wound in the same direction. 6. The coarse / fine adjustment ball screw unit according to claim 2, wherein the ball screw shaft and the ball screw nut / ball screw shaft are wound in opposite directions. 7. The coarse-motion fine-motion ball screw according to claim 2, 3, 4, 5 or 6, wherein the ball screw shaft and the lead of the ball screw groove of the ball screw nut / ball screw shaft are combined arbitrarily. unit.