WO2014108998A1

WO2014108998A1 - Sine bar mechanism for spectrometer

Info

Publication number: WO2014108998A1
Application number: PCT/JP2013/050109
Authority: WO
Inventors: ▲曉▼ 査
Original assignee: 株式会社島津製作所
Priority date: 2013-01-08
Filing date: 2013-01-08
Publication date: 2014-07-17

Abstract

The present invention is a sine bar mechanism for a spectrometer comprising an electric motor (10), a screw bar (3) rotated by the electric motor (10), a frame (2) that rotatably holds the screw bar (3), a guide bar (6) that is disposed in the frame (2) parallel to the screw bar (3), and a slider (4) that is attached to the screw bar (3) and that moves in a direction along the screw bar (3) due to the rotation of the screw bar (3). The slider (4) comprises a first through-hole having a female thread on the interior face that engages with a male thread of the screw bar (3), and the slider (4) is screwed into the first through-hole. Moreover, the slider (4) has an abutting member, which is a bore through which the guide bar (6) is inserted, that abuts the exterior circumferential face of the guide bar (6). The abutting member and the guide bar (6) are attached with high dimensional precision, and thus fluctuations of the slider (4) are limited by a minute gap between the first through-hole of the slider (4) and the screw bar (3).

Description

Sign bar mechanism for spectrophotometer

The present invention relates to a spectrophotometer sign bar mechanism used for rotating a diffraction grating of a spectrophotometer.

Atomic absorption spectrophotometers are widely applied in the fields of medicine, biology, pharmacy, etc. as devices for analyzing the environment, metal semiconductors, and petrochemical polymer materials.

In conventional spectrophotometers, a sine bar mechanism is usually used to rotate the diffraction grating. FIG. 1 is a front sectional view of a conventional sign bar mechanism of a spectrophotometer, and FIG. 2 is a left sectional view. In the following description, the vertical direction and the horizontal direction in FIG. 1 are referred to as “vertical direction” and “horizontal direction”, respectively. A direction perpendicular to the paper surface of FIG. 1 is referred to as “front-rear direction”.

As shown in FIGS. 1 and 2, the conventional spectrophotometer sine bar mechanism includes a frame 2,

bearings

1 and 7 fixed to the frame 2, and both ends rotatably supported by the

bearings

1 and 7. A screw bar 3, an electric motor 10 for rotating the screw bar 3, a guide 6 having both ends fixed to the frame 2 and parallel to the screw bar 3, and a slider 4 held by the screw bar 3. . A first through hole 41 extending in the left-right direction is provided at a substantially middle position in the vertical direction of the slider 4, and an internal thread is provided on the inner peripheral surface of the first through hole 41. The slider 4 is held by the screw bar 3 by screwing the female screw and the male screw of the screw bar 3. A slot 13 that penetrates the slider 4 in the left-right direction and communicates the lower peripheral surface of the first through hole 41 and the lower end surface of the slider 4 is provided at the lower portion of the slider 4. A screw hole that penetrates the slider 4 in the front-rear direction is provided in the lower portion of the slider 4. A screw 5 is screwed into the screw hole, and the width of the slot 13 can be changed by adjusting the screwing amount of the screw 5. Further, by adjusting the screwing amount of the screw 5, the gap between the female screw of the first through hole 41 and the male screw of the screw bar 3 can be adjusted with high accuracy.

The upper end surface of the slider 4 is provided with a groove 12 extending in the left-right direction, and a guide bar 6 is disposed in the groove 12. When the electric motor 10 rotates the screw bar 3, the slider 4 moves to the left and right along the guide bar 6 disposed in the groove 12. A substantially circular hole extending rearward from the groove 12 is formed at the approximate center of the groove 12 in the left-right direction. The rear end of the circular hole is closed. One spring 8 is disposed in the circular hole. The rear end of the spring 8 is in contact with the rear end of the circular hole, and the front end presses the guide bar 6 via the steel ball 9. With such a structure, the gap between the groove 12 of the slider 4 and the guide bar 6 can be reduced, and the movement of the slider 4 in the front-rear direction is limited.

The slider 4 is connected to a turntable on which a diffraction grating is installed via a rod (both not shown). One end of the rod is always in contact with the slider 4 by a spring (not shown), and the other end of the rod is supported by the turntable. When the slider 4 is moved left and right by driving the electric motor 10, the rod swings to rotate the turntable. That is, the linear motion of the slider 4 is converted into rotation of the diffraction grating.

JP 2000-304612 A

In the spectrophotometer sine bar mechanism configured as described above, in order to rotate the diffraction grating with high accuracy, after the electric motor 10 is rotated by a certain angle in the positive direction and the slider 4 is moved, the electric motor 10 is moved at the same angle. When rotating in the opposite direction only, the slider 4 is required to return to its original position. For this reason, the slider 4 and the screw bar 3 need to be screwed with high accuracy. However, in order to allow the slider 4 to move in the left-right direction according to the rotation of the screw bar 3, a certain gap is required between the internal thread of the slider 4 and the external thread of the screw bar 3. The movement in the left-right direction along the 4 guide bars 6 is made unstable. In order to eliminate such instability, in the sine bar mechanism configured as described above, the spring 4 presses the guide bar 6 through the steel ball 9, so that the slider 4 moves back and forth around the screw bar 3. The swinging is restricted. However, because the slider 4 swings left and right or up and down due to the gap still present between the internal thread of the slider 4 and the external thread of the screw bar 3, an error occurs in the amount of movement of the slider 4, and the position of the slider 4 is reproduced. Sex is reduced.

The present invention has been made to solve such a problem, and an object of the present invention is to provide a spectrophotometer sign bar mechanism that can prevent the slider from wobbling.

The sign bar mechanism for a spectrophotometer according to the present invention, which has been made to solve the above problems,
An electric motor,
A screw bar rotated by the electric motor;
A frame for rotatably holding the screw bar;
A guide bar arranged parallel to the screw bar on the frame;
A slider attached to the screw bar and moving along the screw bar as the screw bar rotates.
A first through hole having an internal thread engaging with an external thread of the screw bar;
And a contact member that has a hole through which the guide bar is inserted and contacts the outer peripheral surface of the guide bar.

In the spectrophotometer sine bar mechanism, the contact member includes a plurality of balls that are arranged on the inner peripheral surface of the hole in the axial direction of the guide bar and are in contact with the outer peripheral surface of the guide bar. It is preferable that at least three ball rows are provided, and the at least three ball rows are arranged at equal intervals along the circumferential direction of the guide bar.

It is preferable to provide four ball rows.
The contact member may be a linear bearing.

Further, in the present invention, the contact member can be constituted by a second through hole formed in the slider. In this case, it is preferable that the guide bar is attached to the second through hole so that the wavelength reproducibility during wavelength scanning of the spectrophotometer is nm-0.1 nm to +0.1 nm. It is preferable that the guide bar is attached to the second through hole so that the wavelength reproducibility at the time of wavelength scanning of the total is -0.05 nm to +0.05 nm.

In the present invention, the contact member can be constituted by a second through hole formed in the slider and a bush disposed in the second through hole. In this case, it is preferable that the guide bar is attached to the bush so that the wavelength reproducibility during wavelength scanning of the spectrophotometer is −0.1 nm to +0.1 nm, and further, the wavelength of the spectrophotometer It is preferable that the guide bar is attached to the bush so that the wavelength reproducibility during scanning is in the range of −0.05 nm to +0.05 nm.

According to the present invention, since the slider has a contact member that has a hole through which the guide bar is inserted and contacts the outer peripheral surface of the guide bar, the slider can be prevented from wobbling. For this reason, the wavelength reproducibility at the time of wavelength scanning of a spectrophotometer can be improved. Further, by using a linear bearing as the abutting member, it is possible to reduce friction generated when the slider moves along the guide bar (friction generated between the ball of the linear bearing and the outer ring and the inner ring). For this reason, the slider can be moved with higher accuracy and stability.

Front sectional view of a conventional spectrophotometer sign bar mechanism. FIG. 2 is a left sectional view of the conventional spectrophotometer sign bar mechanism taken along line II-II in FIG. 1. 1 is a front sectional view of an embodiment of a spectrophotometer sign bar mechanism according to the present invention. FIG. The left view sectional view which meets the IV-IV line in Drawing 3 of the sign bar mechanism for a spectrophotometer concerning the present invention.

An embodiment of a spectrophotometer sign bar mechanism according to the present invention will be described with reference to FIGS. In FIGS. 3 and 4, the same or similar members as those in the conventional sign bar mechanism are denoted by the same reference numerals as those in FIGS.

The main difference between the spectrophotometer sign bar mechanism of the present embodiment and the conventional sign bar mechanism is that the slider 4 includes a contact member 11 instead of the groove 12. Since other structures are almost the same as those of the conventional sign bar mechanism, detailed description thereof is omitted here. As shown in FIGS. 3 and 4, a second through-hole penetrating the slider 4 in the left-right direction is formed in the upper part of the slider 4, and a cylindrical ball bush 11 is formed in the second through-hole. It is inserted.

On the inner peripheral surface of the ball bush 11, four rows of ball rows 111 made up of a plurality of balls arranged in a row in the axial direction of the guide bar 6 are arranged. The four ball rows 111 are arranged on the inner peripheral surface of the ball bush 11 at equal intervals in the circumferential direction. All of the four rows of ball rows 111 are in contact with the outer peripheral surface of the guide bar 6. The contact member of the present invention is constituted by the ball bush 11 and the four rows of ball rows 111.

When the electric motor 10 is driven and the screw bar 3 is rotated, the slider 4 moves in the left-right direction along the screw bar 3. At this time, since each ball of the ball row 111 makes point contact with the outer peripheral surface of the guide bar 6, the ball row 111 rotates on the outer peripheral surface of the guide bar 6 with almost no friction with the guide bar 6. Then, the slider 4 is moved along the guide bar 6. At this time, the four rows of ball rows 111 press the guide bar 6 with an equal force from the direction perpendicular to the axial direction of the guide bar 6. Thereby, the movement of the slide 4 in each direction perpendicular to the axial direction of the guide bar 6 is restricted, and the slider 4 can be moved only in the axial direction of the guide bar 6.

As described above, since the sign bar mechanism of the present embodiment has the contact member that prevents the slider 4 from wobbling, the wobbling of the slider 4 in the left-right direction or the up-down direction can be eliminated, and thereby the wavelength scanning of the spectrophotometer. The wavelength reproducibility at the time can be improved.
Here, it is preferable that the dimensional accuracy of the second through hole, the ball bush 11, each ball of the ball row 111, and the guide bar 6 is such that the wavelength reproducibility of the spectrophotometer is -0.1 nm to +0.1 nm. Furthermore, it is more preferable to set the dimensional accuracy so that the wavelength reproducibility is -0.05 nm to +0.05 nm.

In addition, this invention is not limited to an above-described Example, The following modifications are possible.
The four rows of ball rows 111 only need to be arranged at substantially equal intervals along the inner peripheral surface of the ball bushing 11, and the angles of the adjacent two rows of ball rows 111 with respect to the central axis of the guide bar 6 are strictly equal. It is not required to do. In short, it is only necessary that each ball row 111 is configured to press against the outer peripheral surface of the guide bar 6 to such an extent that the slide 4 is restricted from moving in each direction perpendicular to the axial direction of the guide bar 6.

In the above embodiment, the balls of each ball row 111 are arranged on a straight line, but the present invention is not limited to this. It is only necessary that the balls of each ball row 111 are evenly arranged in the axial direction of the guide bar 6. For example, the balls of each ball row 111 may be spirally arranged on the inner peripheral surface of the ball bush 11.

Further, in the above embodiment, four ball rows 111 are provided in the ball bush 11, but it is sufficient that at least three ball rows 111 are provided.
The contact member may be a bearing member including a bearing outer ring and a rolling element. Alternatively, a linear bearing having at least three ball rows between the bearing outer ring and the bearing inner ring may be used as the contact member.

In the above embodiment, the contact member is constituted by the ball bush 11 and the ball row 111. However, the ball bush 11 may be omitted, and at least three ball rows may be arranged directly on the inner peripheral surface of the second through hole. Good. In such a configuration, the contact member is constituted by the second through hole and the ball row.

The abutting member may be composed of a second through hole and a bush provided therein, and the guide bar may be inserted into the bush. In this case, by providing a small gap between the bush and the guide bar so as not to hinder the movement of the slider 4 along the guide bar 6, the slide 4 can move in each direction perpendicular to the axial direction of the guide bar shaft 6. Can restrict movement.

DESCRIPTION OF

SYMBOLS

1, 7 ... Bearing 2 ... Frame 3 ... Screw bar 4 ... Slider 41 ... 1st through-hole 5 ... Screw 6 ... Guide bar 8 ... Spring 9 ... Steel ball 10 ... Electric motor 11 ... Ball bushing 111 ... Ball row 12 ... Groove 13 ... Slot

Claims

An electric motor,
A screw bar rotated by the electric motor;
A frame for rotatably holding the screw bar;
A guide bar disposed in parallel with the screw bar on the frame;
In a spectrophotometer sign bar mechanism comprising a slider attached to the screw bar and moving along the screw bar as the screw bar rotates, the slider includes:
A first through hole having an internal thread engaging with an external thread of the screw bar;
A sign bar mechanism for a spectrophotometer, comprising: a hole through which the guide bar is inserted, and a contact member that contacts the outer peripheral surface of the guide bar.
The spectrophotometer sign bar mechanism according to claim 1,
The abutting member includes at least three ball rows composed of a plurality of balls that are arranged on the inner peripheral surface of the hole in the axial direction of the guide bar and are in contact with the outer peripheral surface of the guide bar,
The spectrophotometer sine bar mechanism, wherein the at least three ball rows are arranged at equal intervals in the circumferential direction of the guide bar.
In the spectrophotometer sign bar mechanism according to claim 2,
4. The spectrophotometer sine bar mechanism according to claim 1, wherein the ball rows are four rows.
The spectrophotometer sign bar mechanism according to any one of claims 1 to 3,
The spectrophotometer sine bar mechanism, wherein the contact member is a linear bearing.
The spectrophotometer sign bar mechanism according to claim 1,
The contact member is a second through hole formed in the slider;
The sign bar mechanism for a spectrophotometer, characterized in that the guide bar is attached to the second through hole so that the wavelength reproducibility during wavelength scanning of the spectrophotometer is -0.1 nm to +0.1 nm. .
The spectrophotometer sign bar mechanism according to claim 1,
The contact member is a second through hole formed in the slider;
A sign bar mechanism for a spectrophotometer, characterized in that the guide bar is attached to the second through hole so that the wavelength reproducibility during wavelength scanning of the spectrophotometer is -0.05 nm to +0.05 nm. .
The spectrophotometer sign bar mechanism according to claim 1,
The contact member includes a second through hole formed in the slider, and a bush disposed in the second through hole.
The sign bar mechanism for a spectrophotometer, wherein the guide bar is attached to the bush so that wavelength reproducibility during wavelength scanning of the spectrophotometer is -0.1 nm to +0.1 nm.
The spectrophotometer sign bar mechanism according to claim 1,
The contact member comprises a second through hole formed in the slider, and a bush disposed in the second through hole,
The sign bar mechanism for a spectrophotometer, wherein the guide bar is attached to the bush so that wavelength reproducibility during wavelength scanning of the spectrophotometer is -0.05 to +0.05 nm.