JPS6014042Y2 - High-speed feed screw device - Google Patents

Description

[Detailed description of the invention] The present invention is a drive device for an X-Y table (a table that moves in the X direction and the Y direction that are perpendicular to each other in a horizontal plane) used in various mechanical devices, for example. This is a high-speed feed screw device that is ideal for application to a feed screw driven by a motor at high speed, a nut engaged with the feed screw, and an X-Y table to which the nut is connected. The present invention relates to a high-speed feeding screw device that is configured to include a moving member and to feed the moving member at high speed via a nut by high-speed rotation of a feed screw.

Figure 1 shows a high-speed feed screw device in a conventional X-Y table drive device, in which a trapezoidal screw is used as the feed screw 1, and a pair of nuts 2 and 3 are tightened on the nut. For attachment, a double nut 5 which is mutually tightened with a screw 4 is used.

At this time, as shown in FIG. 2, there is a gap 6 in the radial direction between the outer periphery of the feed screw 1 and the inner periphery of the double nut 5 due to the structure of the trapezoidal screw.
A gap 7 in the axial direction (thrust direction) is required for sliding movement.

On the other hand, this type of high-speed feed screw device supports both ends of the feed screw 1 by a pair of bearings, and has a double nut 5 in the middle.
are placed.

Therefore, if there is a radial gap 6 as described above, the feed screw 1
During the high-speed rotation of the feed screw 1, a skipping phenomenon occurs in the feed screw 1 (a phenomenon in which the middle portion of the feed screw is swung around in an arched manner using the pair of bearing portions at both ends as fulcrums).

At this time, the inclination angle θ of the screw retaining surfaces 8 and 9 with respect to the axis
is, for example, 30', the above radial clearance CR
The relationship between C and the axial clearance C is CR= Ca/la
n3°0, and the amplitude of the feed screw 1 due to the clearance CR and Cyu is S'2CR.

That is, in the past, when trying to rotate the feed screw 1 at high speed, a skipping phenomenon occurred in the feed screw 1, causing the entire device to vibrate significantly and making it impossible to move the X-Y table smoothly. However, there was a drawback that the rotational speed of the feed screw 1 was limited and the X-Y table could not be moved at high speed.

Furthermore, conventionally, no measures have been taken to prevent the lubricating oil (grease) applied to the sliding surfaces of the feed screw 1 and the double nut 5 from being retained, and when the feed screw 1 is rotated at high speed, the lubricating oil is As a result, the necessary lubrication of the sliding surfaces was insufficient, and galling, abnormal vibrations, abnormal noises, etc. were likely to occur due to lack of the lubricant film.

For this reason, in the past, lubricating oil had to be replenished frequently at short intervals, which was very disadvantageous in terms of maintenance.

The present invention was devised to correct the above-mentioned defects, and is capable of moving the moving member at high speed by rotating the feed screw at high speed, and also significantly reducing the number of times lubricating oil is replenished. This is what we are trying to provide.

An embodiment in which the present invention is applied to an X-Y table driving device will be described below with reference to FIGS. 3 and 4.

First of all, FIG. 3 shows the entire X-Y table, in which a fixed base 11 placed at the bottom has a longitudinal shape, and a pair of guide rails 12 are provided in parallel on the upper part. .

A longitudinal sliding table 13 is placed on top of the fixed table 11 so as to be perpendicular to the fixed table 11.

The sliding table 13 has a guided portion 1 provided at its lower part.
4 is slidably engaged with both guide rails 12,
This sliding table 13 is configured to be slid horizontally on the fixed table 11 in the X direction.

A pair of guide rails 1 parallel to the upper part of the sliding table 13
5 is provided perpendicular to both guide rails 12.

An XY table 16 is placed on the top of the sliding table 13.

The X-Y table 16 is slidably engaged with both guide rails 15 by a guided portion 17 provided at its lower part, and this X-Y table 16 is placed horizontally in the Y direction on the sliding base 13. It is configured to be slid on.

On the other hand, a pair of feed screws 20 are provided on the upper portions of the fixed base 11 and the sliding base 13 along the center portion between both guide rails 12,15.

Both ends of these feed screws 20 are rotatably supported by a pair of bearings 21 fixed to the upper portions of the fixed base 11 and the sliding base 13, respectively.

Further, one ends of both of the feed screws 20 are connected to a pair of motors 22 fixed to the upper portions of the fixed base 11 and the sliding base 13.

Double nuts 23 fixed to the lower portions of the slide table 13 and the XY table 16 are respectively engaged with intermediate portions of both feed screws 20.

Therefore, by driving both feed screws 20 in forward or reverse rotation with both motors 22, both double nuts 23 are screw-fed, and the X-Y table 16 is
It is configured so that it can be driven horizontally in both the direction and the Y direction.

Next, FIG. 4 shows details of the engaging portion between the feed screw 20 and the double nut 23. First, the feed screw 20
trapezoidal screws are used.

Further, the double nut 23 is constituted by a pair of nuts 24 and 25 that are tightened together by a screw 26.

An annular lubricating oil reservoir 28 is provided on the inner periphery of the central portion of the double nut 23 in the axial direction S, and this lubricating oil reservoir 28 is passed through a passage 30 from an oil filler port 29 provided in the other nut 24. The inside is filled with lubricating oil (grease) G.

In addition, feed screws 2 are attached to both ends of the double nut 23 in the axial direction.
A pair of threaded outer diameter retaining rings 31, 32 are provided which are in close contact with the outer periphery 20a of the screw.

That is, the inner circumference 31 of the outer diameter retaining ring 31, 32 of both screw nuts.
a and 32a are in contact with the outer periphery 20a of the feed screw 20 with an extremely small gap necessary for sliding in the axial direction.

The outer diameter retaining rings 31 and 32 are fastened to the side surfaces of the nuts 24 and 25 by screws 33 and 34, respectively, so that they are coaxial.

According to the high-speed feed screw device configured as described above, when the feed screw 20 is rotated and the double nut 23 is screw-fed, the lubricant G stored in the lubricant oil reservoir 28 is transferred to the feed screw. Mutual sliding surface 3 between 20 and double nut 23
It will be applied automatically between 5.36 and 36 minutes.

When the feed screw 20 is rotated at high speed, the lubricating oil G is scattered on the outer diameter side of the feed screw 20, but the scattered lubricating oil G is inside the outer diameter retaining rings 31 and 32 of both screws. It is automatically scraped off to the inner diameter side of the feed screw 20 by the circumference 31at31b.

Therefore, a necessary amount of lubricating oil G is always retained between the mutual sliding surfaces 35 and 36 of the feed screw 20 and the double nut 23, and sufficient lubrication is achieved.

As a result, by replenishing the lubricating oil G once, the lubricating oil G can be used extremely effectively, and the lubricating oil is less likely to run out.
The number of times lubricant G is replenished can be significantly reduced.

Further, according to this high-speed feeding screw device, since the both screw outer diameter retaining rings 31 and 32 are in close contact with the outer periphery of the feed screw 20 at both ends of the double nut 23, when the feed screw 20 rotates at high speed. It is possible to prevent vibrations caused by the rope skipping phenomenon.

The experimental results show that in the conventional example shown in Figure 1, abnormal vibration occurred in the nut when the rotational speed of the feed screw was around 200 rpm, making it unusable. For example, if the rotation speed of the feed screw is 2
No abnormal vibration occurred even when the rotation speed was increased to 000 rpm, and operation at this rotation speed was possible.

As a result of the above, according to this high-speed feed screw device, the feed screw 20 can be driven to rotate at high speed, and the X-Y table 16 can be moved at high speed.

Although the embodiments of the present invention have been described above, the feed screw referred to in the present invention does not necessarily have to be a trapezoidal screw, and the nut does not necessarily have to be a double nut.

These feed screws and nuts can be modified into various structures.

Furthermore, the present invention is not limited to a drive device for an X-Y table, but can be applied to various screw devices in which various moving members are screwed through a nut by rotation of a feed screw.

As described above, according to the present invention, a lubricating oil reservoir is provided on the inner periphery of the approximately central portion of the nut in the axial direction, and a pair of screw outer diameter retaining rings are fixed to both ends of the nut in the axial direction. By bringing the inner periphery of the screw outer diameter retaining ring into close contact with the outer periphery of the feed screw, both ends of the nut are closed by the pair of screw outer diameter retaining rings, so that there is no leakage from both ends of the nut to the outside. The outflow of lubricating oil can be prevented as much as possible by a pair of screw outer diameter retaining rings.

As a result, it is possible to prevent the lubricant from running out on the sliding surface between the feed screw and the nut, significantly reducing the number of times the lubricant needs to be replenished, and also to prevent vibrations caused by the skipping phenomenon when the feed screw rotates at high speed. This has the advantage that the feed screw can be rotated at high speed without vibration, and the moving member can be moved at high speed.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the main part of the conventional example, and FIG. 2 is an enlarged view of the main part of the same. FIG. 3 is a perspective view showing an embodiment in which the present invention is applied to an X-Y table drive device, and FIG. 4 is a sectional view of the main parts of the same. In addition, in the symbols used in the drawings, 16...X-
Y table, 20...Feed screw, 21...
...Bearing, 22...Motor, 23...
Double nuts, 24゜25...nuts, 28.
... Lubricating oil reservoir, 31, 32 ... Thread outer diameter retaining ring, 35.36 ... Sliding surface, G ...
...It is a lubricating oil.

Claims (1)

[Scope of utility model registration request] It consists of a feed screw that is rotated at high speed by a motor, a nut that is engaged with the feed screw, and a moving member that is connected to the nut.The high speed rotation of the feed screw causes the moving member to be sent at high speed through the nut. In the high-speed feeding screw device, a lubricating oil reservoir is provided on the inner periphery of the nut at approximately the center in the axial direction, and a pair of screw outer diameter retaining rings are provided at both ends of the nut in the axial direction. A high-speed feed characterized in that both ends of the nut are closed by the pair of screw outer diameter retaining rings by fixing and bringing the inner circumference of the screw outer diameter retaining rings into close contact with the outer circumference of the feed screw. screw device.