JP2004279659A - Screw-feeding mechanism and spatial light transmitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that the accuracy of a screw-feeding mechanism is deteriorated due to the vibration and decentering of the driving shaft of a nut used for the screw-feeding mechanism. <P>SOLUTION: As for the screw-feeding mechanism of driving a stage while receiving the rotation of a driving shaft as a reference of the stage in a driving direction and a 1st screw (male screw) arranged in nearly parallel to the driving shaft by a 2nd screw (nut), at least one shaft is arranged so that it can rotate and slide around a 2nd screw, then, such the effects can be obtained that the 2nd screw (nut) smoothly follows the vibration and decentering of the driving shaft. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an improvement in coupling between a nut of a general screw feed mechanism and a stage on a driven side, and is particularly suitable for a tracking mechanism of an optical space transmission device that transmits information wirelessly to a remote place. is there.
[0002]
[Prior art]
Generally, when a screw feed mechanism is used, it is often the case that a shaft serving as a reference in the driving direction, a male screw is mounted on the fixed side, and a nut engaging with the male screw is mounted on the stage on the driven side. The nut is fixed to the stage. In this case, it is necessary to perform operations such as parallelizing the shaft serving as a reference in the driving direction and the male screw, and positioning the nut and the male screw.
[0003]
In some cases, the nut is molded from an elastic material such as a resin, and the positioning operation is omitted by bending the nut.
[0004]
[Problems to be solved by the invention]
In the case of the above-described screw feed mechanism, not only takes time for parallel alignment and alignment work, but if the alignment is incomplete, an eccentric load and a twist are generated. Such an eccentric load or twisting deteriorates the accuracy of the screw feed mechanism and greatly affects the service life.
[0005]
Further, when the nut is formed of an elastic material, the nut is bent in the driving direction of the stage, so that the nut cannot be used except when the mass of the object driven on the stage is small.
[0006]
In addition, when a screw feed mechanism is used for the tracking mechanism of the optical space transmission device, periodic maintenance is necessary due to deterioration of the member due to long-term outdoor use and deformation of the member due to temperature change, etc. It is burdensome.
[0007]
In addition, eccentric load and kinking occur due to runout and eccentricity of the drive shaft of the nut used in the screw feed mechanism, and the accuracy of the screw feed mechanism is deteriorated.
[0008]
[Means for Solving the Problems]
In order to solve the above-described problem, in the present invention, the rotation of a first screw installed substantially parallel to the drive shaft serving as a reference for the drive direction of the stage is received by a second screw. In the screw feed mechanism for driving the stage, at least one axis that can rotate and slide around the second screw is provided.
[0009]
That is, in the present invention, the second screw (= nut) is kept highly rigid in the rotation direction of the first screw (= male screw) and the driving direction of the stage, and has a high degree of freedom in all other directions. A screw feed mechanism is provided.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
(Example)
FIG. 1 shows a configuration of a screw feed mechanism according to an embodiment of the present invention. When the male screw 8 rotates, it is transmitted from the nut 1 to the stage 7 via the first annular member 2, the shaft 3, the second annular member 4, the shaft 5, and the base 6, and the stage 7 is moved along the drive shaft 9. Drive in the middle and left and right directions.
[0011]
FIG. 2 is a front sectional view of a nut portion according to the embodiment of the present invention. The nut 1 is integrally fixed to the first connecting member 2. The shaft 3 is coaxially fixed to the outer peripheral portion of the first connecting member. The shaft 3 is engaged with a fitting hole 4a formed in the second annular member 4 so as to be able to smoothly rotate and slide without play. A shaft 5 is coaxially fixed on the outer periphery of the second annular member 4 on a shaft orthogonal to the fitting hole 4a. The shaft 5 is engaged with a fitting hole 6a provided in the base portion 6 so as to be able to smoothly rotate and slide without play. The base 6 is fixed to the stage.
[0012]
With the above configuration, when the male screw 8 rotates and a driving force is generated in the nut 1, the nut 1 is held with high rigidity in the driving direction of the stage 7 and the rotating direction of the male screw 8. Is maintained at a fixed position with respect to the stage 7, and the rotation of the male screw 8 is directly converted into driving of the stage 7.
[0013]
FIG. 3 shows the state of the nut 1 when the male screw 8 is eccentric with respect to the drive shaft 9. In FIG. 3A, the male screw 8 is eccentric in the axial direction of the shaft 3. In FIG. 3B, the male screw 8 is eccentric in the axial direction of the shaft 5. Further, in FIG. 3 (c), the male screw 8 is eccentric in both the axial directions of the shaft 3 and the shaft 5, but in any case, the shaft is smoothly slid in the axial direction with respect to the fitting hole. Is possible, the nut 1 is automatically aligned in accordance with the eccentricity of the male screw.
[0014]
FIG. 4 shows an AA cross section of FIG. FIG. 4A shows a state in which the male screw 8 is attached to the drive shaft 9 at an angle around the shaft 3 at this time. At this time, since the shaft 3 can smoothly rotate with the fitting hole 4a, the nut can follow the inclination of the male screw.
[0015]
FIG. 5 shows a BB cross section of FIG. FIG. 5A shows a state in which the male screw 8 is attached to the drive shaft 9 at an angle around the shaft 5 at this time. At this time, since the shaft 5 can rotate smoothly with the fitting hole 6 a, the nut 1 can follow the inclination of the male screw 8.
[0016]
Further, the nut 1 of the screw feed mechanism of the present embodiment can automatically align the male screw 8 and adjust the angle even when the eccentricity and the inclination of the shaft occur simultaneously as described above.
[0017]
FIG. 6 shows a configuration when the screw feed mechanism of this embodiment is used for a tracking mechanism of an optical space transmission device. When the lens elements are driven, for example, in the vertical direction and the horizontal direction in order to align the optical axis, at least one set of screw feed mechanisms is configured and driven in each direction (only the vertical direction is shown). When the deviation of the optical axis from the partner device is detected, a signal is sent from the control circuit to the tracking drive circuit, and the drive circuit drives the motor. The motor rotates the male screw to drive the stage. At this time, if a thread play occurs between the male screw 8 and the nut 1, an urging means for removing the play is provided so that the nut 1 is always pressed against the male screw 8 in a fixed direction. Constitute.
[0018]
As described above, in the screw feed mechanism of the present embodiment, the nut 1 automatically adjusts the center and the angle with respect to the male screw 8, so that the adjustment work at the time of assembly is unnecessary, and the screw feed mechanism is not used. The life is also dramatically improved. In addition, since the rigidity in the driving direction and the rotation direction of the male screw 8 is high and there is little backlash, it is possible to drive heavy objects with high accuracy. Furthermore, as long as interference with the male screw 8 does not occur, there is no restriction on the mounting angle and the like, so there is no need to provide an angled seat or the like for mounting the nut 1, and the nut is simply mounted on a part having an easily formed shape. Will be better.
[0019]
In addition, by using the screw feed mechanism of the present embodiment for optical axis alignment of the optical space transmission device, it is possible to simplify the assembly of the product and shorten the assembly time by eliminating the need for adjustment, and to increase the life of the screw feed mechanism. This makes it possible to reduce the number of regular repairs after product shipment. Further, when the urging means for the screw backlash is provided, more accurate control is possible.
[0020]
[Embodiments of the present invention]
While various examples and embodiments of the present invention have been shown and described, those skilled in the art will recognize that the spirit and scope of the present invention is not limited to the specific description and figures herein, but rather to It will be appreciated that various modifications and changes are set forth which are all set forth in the following claims.
[0021]
Examples of embodiments of the present invention are listed below.
[0022]
[Embodiment 1]
A drive shaft serving as a reference for the drive direction of the stage 77, and a screw feed mechanism that receives the rotation of a first screw installed substantially parallel to the drive shaft with a second screw and drives the stage,
A screw feed mechanism provided with at least one axis rotatable and slidable around a second screw.
[0023]
[Embodiment 2]
3. The screw feed mechanism according to claim 2, wherein the axis capable of rotating and sliding around the second screw has two axes orthogonal to the second screw.
[0024]
[Embodiment 3]
A base portion for fixing to the stage around the second screw and two connecting members are provided, the second screw is integrally fixed to the first connecting member, and the first with the second screw is provided. Is provided with a first shaft, and the first shaft is rotatably and axially slidably engaged in a fitting hole provided in the second connection member, and the second connection A second shaft is provided at a position orthogonal to the fitting hole on the member, and the second shaft is engaged with the fitting hole provided on the base portion so as to be able to rotate and slide in the axial direction. The screw feed mechanism according to claim 2, wherein the screw feed mechanism is characterized in that:
[0025]
[Embodiment 4]
A base portion for fixing to the stage and two connecting members are provided around the second screw, the second screw is integrally fixed to the first connecting member, and the first screw with the second screw is provided. The connecting member is provided with a first shaft, the first shaft is engaged with a fitting hole provided in the second connecting member via a bearing capable of rotation and axial movement, A second shaft is provided on the second connecting member at a position orthogonal to the fitting hole, and the second shaft is provided on a fitting hole provided on the base portion via a bearing that can rotate and move in the axial direction. The screw feed mechanism according to claim 2, wherein the screw feed mechanism is engaged with the screw.
[0026]
[Embodiment 5]
The screw feed mechanism according to any one of embodiments 1 to 4, wherein a biasing means such as a spring is provided in a feed direction of the first screw.
[0027]
[Embodiment 6]
An optical space transmission device, wherein the screw feed mechanism according to any one of the first to fifth embodiments is mounted on a drive unit of a tracking mechanism that drives an optical element to automatically align an optical axis with a counterpart device. .
[0028]
【The invention's effect】
As described above, according to the present invention, the rotation of the first screw (= male screw) installed substantially parallel to the drive shaft and the second screw (= In a screw feed mechanism receiving the nut and driving the stage, at least one shaft that can rotate and slide around the second screw is provided, and the second screw (= nut) is used to prevent the deflection of the drive shaft. The effect of smoothly following the eccentricity is obtained.
[Brief description of the drawings]
FIG. 1 is a typical configuration of a screw feed mechanism of the present invention. FIG. 2 is a front sectional view of a nut portion of the screw feed mechanism of the present invention. FIG. Alignment of nut when cored (b) Alignment of nut when male screw is eccentric in the axial direction of shaft 5 (c) Eccentricity of male screw in axial direction of shaft 3 and shaft 5 [FIG. 4] AA sectional view of FIG. 1 (a) A state of nut alignment when a male screw is tilted around the axis 3 [FIG. 5] B- FIG. B sectional view (a) State of angle adjustment of nut when male screw is inclined around axis 5 [FIG. 6] Configuration of optical space transmission device using screw feed mechanism of the present invention [Description of reference numerals]
Reference Signs List 1 nut 2 first annular member 3 shaft 4 second annular member 4a fitting hole 5 shaft 6 base 6a fitting hole 7 stage 8 male screw 9 drive shaft

Claims (1)

A drive shaft serving as a reference for the drive direction of the stage, and a screw feed mechanism that receives the rotation of a first screw installed substantially parallel to the drive shaft with a second screw and drives the stage,
A screw feed mechanism provided with at least one axis rotatable and slidable around a second screw.

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