JP2005152819A - Centrifuge and rotor for centrifuge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce defective swing of a swing rotor for centrifuge and to prolong the life of a bucket. <P>SOLUTION: The centrifuge has an engagement part annular groove 3 disposed on the bucket 5 and a round part 9 disposed on the annular groove, for providing such a structure that the bucket 5 is brought into point-contact or line-contact with the outside diameter surface of a rotor pin 2 and, a stress is not concentrated in the vicinity of the contact part between the bucket 5 and the rotor pin 2. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a centrifuge and a centrifuge rotor.

  A conventional centrifuge swing rotor will be described with reference to FIGS. There are various types of swing rotors for centrifuges. In general, swings are placed on opposite sides of a bucket storage portion 12 formed by a pair of rotor arm portions 1 provided on the outer peripheral portion of the rotor body. A cylindrical rotor pin 2 serving as a fulcrum is disposed. Further, pin engaging portions 7 are formed on both side surfaces of the bucket 5 into which the sample is placed so as to engage with the rotor pin 2, and engage with the rotor pin 2 to swing. The rotor pin 2 may be attached to a through hole provided in the rotor arm portion 1 with a separate or cylindrical member integrated with the rotor arm portion 1. In either case, when the rotor rotates, centrifugal force acts on the bucket 5 so that it can swing 90 ° horizontally around the bucket rotation center 6. Further, a sealing cap may be provided on the upper surface of the bucket.

  Conventionally, the contact portion of the rotor pin 2 and the pin engaging portion 7 of the bucket 5 is formed in a similar shape so as to increase the contact area so as to withstand the load of the centrifugal force of the bucket 5 and the sample 14. Therefore, there are many contact parts, and the contact part between the rotor pin 2 and the pin engaging part 7 is damaged due to wear due to repeated swinging, so that contact resistance increases and a swing failure is likely to occur. In the worst case, the rotation of the rotor stops. However, the bucket may not return from the horizontal state. Also, due to scratches caused by wear due to the swing, the scratches at the contact boundary 8 of the bucket 5 become notches and cracks occur, and a contact stress singularity is generated near the crack tip. It was.

  For example, as described in Japanese Patent Laid-Open No. 2002-113388, the tip of the rotor pin extends in a tapered shape in the outer diameter direction, and the rotor pin and the bucket recess are in line contact during centrifugation, and during stop, the contact surface becomes a point or line contact and the contact surface becomes It has been proposed to provide means that are less likely to be damaged and that cause poor swing failure. While it is described that the bucket and the pin are in line contact during centrifugation, nothing is described about the configuration in which the bucket and the rotor pin are always in point contact.

  Further, as described in Japanese Utility Model Laid-Open No. 6-39140, a structure has been proposed in which the engagement pin and the bucket are brought into line contact with each other to increase the contact portion, and as described in Japanese Utility Model Laid-Open No. Hei 6-39141. Although it has been proposed to provide a reinforcing member on the opposite surface of the engaging portion of the bucket, nothing is described about providing an annular groove in the circumferential outer peripheral direction of the rotor pin in the engaging portion of the bucket .

JP 2002-113388 A

Japanese Utility Model Publication No. 6-39140 Japanese Utility Model Publication No. 6-39141

  In the above-described conventional swing rotor, a phenomenon that the rotor pin and the bucket are fixed to each other during repeated use may occur. This phenomenon is caused by the fact that the rotor body and the bucket are deformed by the centrifugal force, and at this time, wear powder, scratches in the rotation direction of the bucket, and the like are generated at the contact portion of the engaging portion, and it becomes difficult to swing. In this case, the swinging state of the buckets at the symmetric position becomes uneven and unbalanced operation results in increased rotational vibration, or when the rotation stops, the bucket stops tilting and the sample spills out. This could damage the centrifuge and damage the user's property. In addition, a tensile load acts on the rotor pin center axis direction due to the deformation of the bucket at the contact boundary portion between the bucket and the rotor pin during centrifugation, and the above-mentioned scratch becomes a notch effect, causing stress concentration and reducing the life of the bucket. there were. An object of the present invention is to eliminate the above-described problem of the swing rotor for a centrifuge, to provide a structure in which the swinging motion of the bucket can always be smoothly rotated, and to improve the life of the bucket.

  A drive shaft that is rotated by a drive device, a rotor body that is mounted on the rotation shaft, a bucket storage portion formed on the rotor body, a columnar pin portion disposed in the bucket storage portion, and the pin portion And a centrifuge having a swing rotor having a plurality of buckets arranged so as to be swingable via the pin engaging portion, the pin engaging portion is provided with an annular groove, and the pin portion end surface and the pin engaging portion This is achieved by configuring the engagement portion annular groove to be larger in width than the gap between the portion end faces.

Further, this is achieved by providing an annular groove round portion in the engagement portion annular groove, and providing a radius of curvature of the annular groove round portion to ½ of the engagement portion annular groove.
A driving shaft rotated by the driving device; a rotor body mounted on the rotating shaft; a bucket storage portion formed on the rotor body; a columnar pin portion disposed in the bucket storage portion; In a swing rotor having a plurality of buckets arranged so as to be swingable via a pin portion and a pin engaging portion, an annular groove is provided in the pin engaging portion, and the pin portion end surface and the pin engaging portion end surface This is achieved by configuring the engagement portion annular groove to be wider than the clearance.

  Further, this is achieved by providing an annular groove round portion in the engagement portion annular groove, and providing a radius of curvature of the annular groove round portion to ½ of the engagement portion annular groove.

  As described above, according to the present invention, the swingability of the centrifuge swing rotor can be improved, the life of the bucket can be extended, and a bucket mounting structure with high safety can be provided.

An embodiment of a swing rotor for a centrifuge of the present invention will be described with reference to FIGS. 1, 2, 3, 4 and 7.
FIG. 1 is a cross-sectional view showing a centrifuge 20 mounted with a centrifuge swing rotor 10 of the present invention and a bucket that is swingably supported by the centrifuge swing rotor 1. A bucket 5 drawn with a dotted line represents a state where the rotor 10 is stopped, and a solid line represents a state where the rotor 10 is rotating.

  The centrifuge swing rotor 10 is arranged to be driven to rotate by a drive device 23 arranged so as to protrude into the rotation chamber 22 of the centrifuge 20, and the centrifuge 20 to the rotor 10 and the bucket are disposed above the rotation chamber 22. 5 or a door 25 for taking out the sample container 13 containing the sample 14 is disposed so as to be openable and closable. FIG. 3 is a cross-sectional view showing a state in which the bucket 5 is attached to the rotor pin 2, wherein 1 is a rotor arm portion, 2 is a rotor pin, 3 is an engagement portion annular groove, 5 is a bucket, 6 is a bucket rotation center, and 8 is A contact boundary 9 is an annular groove round portion. In this embodiment, the rotor pin 2 and the rotor body 11 are formed as separate parts, but the rotor pin 2 and the rotor body 11 may be provided integrally.

  The centrifuge swing rotor rotates through the rotation shaft 24 of the drive device 23, so that the plurality of buckets 5 that are swingably arranged in the bucket storage portion 12 of the rotor are centered around the bucket rotation center 6 by centrifugal force. It is structured to swing 90 ° in the horizontal direction. FIG. 2 is an enlarged sectional view of the vicinity of the rotor pin 2. FIG. 5 is a cross-sectional view taken along the line A-A in FIG. 3, showing a contact portion between the bucket 5 and the rotor pin 2.

  The most important point in the present embodiment is that the groove width L2 of the engaging portion annular groove 3 formed to have a gap is larger than the distance L1 between the bucket 5 and the end face of the rotor pin (L2> L1). And the bucket rotation center 6 (center axis of the rotor pin 2) in the state where the bucket 5 is set on the rotor pin 2 and the distance L3 (radius of the rotor pin 2) to the outer surface of the rotor pin 2 The distance L4 to the apex of the joint annular groove 3 is large (L4> L3).

  There are two reasons why the engaging portion annular groove 3 is formed. One is to make the line contact portion at the contact position 4 of the rotor pin 2 and the bucket 5 as small as possible or to make point contact. By making the line contact portion as small as possible or point contact, the rotor pin 2 and By reducing the range of wear powder and scratches at the engaging portion of the bucket 5, the frictional resistance can be reduced, the bucket can be easily swung, and the phenomenon in which the bucket 5 and the rotor pin are firmly fixed is greatly improved. Because.

  However, since the contact portion is reduced, the pressure at the contact portion between the bucket 5 and the rotor pin 2 during centrifugation is larger than that of the conventional structure, but the compressive stress is dominant in the stress generated at the contact position 4 portion. There is almost no effect on the life of the bucket. Actually, as a result of comparing the life of the embodiment of the present invention shown in FIG. 3 with that of FIGS. 3 and 4 of the conventional embodiment, the embodiment of the present invention showed a life equal to or longer than that of the conventional embodiment.

  Another reason is to provide a larger rounded portion in a limited space. Stress is concentrated on the annular groove rounded portion 9 due to the load of the bucket 5 itself and the sample 14 and the sample container 13 loaded therein due to the centrifugal force. Therefore, the larger the annular groove rounded portion 9 is, the more stress can be relaxed. In the present embodiment, the radius of curvature of the annular groove rounded portion 9 is ½ (L2 / 2) of the groove width L2 of the engaging portion annular groove 3. Needless to say, when there is an allowance in terms of stress, the radius of curvature may be set to ½ or less of the groove width L2 of the engagement portion annular groove 3.

  Further, by adopting the form of the present invention, since the tensile load in the direction of the bucket rotation center 6 due to the deformation of the bucket 5 does not act on the contact boundary 8 portion, the rotation of the bucket generated in the sliding portion between the bucket 5 and the rotor pin 2 is achieved. Since the stress concentration due to the direction scratch does not occur, the life of the bucket 5 is improved.

  From the above, it acts on the contact position 4 between the bucket 5 and the rotor pin 2 due to an increase in rotational vibration due to aggravation of the swing due to wear powder or abrasion at the contact portion of the engaging portion, which was a problem in the conventional swing rotor. If the structure in which the engagement portion annular groove 3 is provided in the bucket 5 and the rounded portion 9 is provided in the annular groove can be solved by reducing the strength of the bucket due to the concentrated stress, these problems can be solved.

The fragmentary sectional view of one Embodiment which shows the state which employ | adopted the swing rotor for centrifuges of this invention for the centrifuge. The plane part of one Embodiment of the swing rotor for centrifuges of this invention. The partial expanded sectional view which shows one Embodiment of the bucket attachment structure for this invention centrifuge. The partial expanded sectional view of FIG. 3 which shows one Embodiment of the bucket attachment structure for this invention centrifuge. The principal part expanded sectional view which shows an example of the conventional bucket attachment structure for centrifuges. The principal part expanded sectional view which shows an example of the conventional bucket attachment structure for centrifuges. Sectional drawing which shows AA embodiment of the bucket attachment structure for this invention centrifuge.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 is a rotor arm part, 2 is a rotor pin, 3 is an engagement part annular groove, 4 is a contact position, 5 is a bucket, 6 is a bucket rotation center, 7 is a pin engagement part, 8 is a contact boundary, 9 is an annular groove are , 10 is a swing rotor for a centrifuge, 11 is a rotor body, 12 is a bucket storage unit, 13 is a sample container, 14 is a sample, 20 is a centrifuge, 22 is a rotating chamber, 23 is a driving device, 24 is a rotating shaft, Reference numeral 25 denotes a door.

Claims (4)

A drive shaft that is rotated by a drive device, a rotor body that is mounted on the rotation shaft, a bucket storage portion formed on the rotor body, a columnar pin portion disposed in the bucket storage portion, and the pin portion And a centrifuge having a swing rotor having a plurality of buckets arranged so as to be swingable via the pin engaging portion, the pin engaging portion is provided with an annular groove, and the pin portion end surface and the pin engaging portion A centrifuge equipped with a swing rotor, characterized in that the width of the engagement portion annular groove is larger than the gap with the end face of the portion. 2. The centrifuge according to claim 1, wherein an annular groove rounded portion is provided in the engaging portion annular groove, and a radius of curvature of the annular groove rounded portion is provided at a half of the engaging portion annular groove. A drive shaft that is rotated by a drive device, a rotor body that is mounted on the rotation shaft, a bucket storage portion formed on the rotor body, a columnar pin portion disposed in the bucket storage portion, and the pin portion And a swing rotor including a plurality of buckets arranged so as to be swingable via the pin engaging portion, an annular groove is provided in the pin engaging portion, and the pin portion end surface and the pin engaging portion end surface A swing rotor characterized in that the width of the engaging portion annular groove is larger than the gap. The swing rotor according to claim 1, wherein an annular groove round portion is provided in the engagement portion annular groove, and a radius of curvature of the annular groove round portion is provided at a half of the engagement portion annular groove.

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