JP2008221129A - Centrifugal separator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a centrifugal separator which enables a rotor to be easily detachably attached to a drive shaft while securing a sufficient combining force in a rotating rotor. <P>SOLUTION: The centrifugal separator is provided with the rotor 50 for storing a sample and a drive device for rotating the rotor 50. In the centrifugal separator, a fitting hole 50e fitted to the drive device is formed in the rotor 50, and a weight 3 (a protruding member for preventing idling) is stored at the bottom of the fitting hole 50e, and a similar protruding member for preventing idling is formed at the drive shaft 35 of the drive device. An elastic seal member 7 is formed at the outer circumference of the drive shaft 35 and a plurality of holes 8 communicating with the outside are formed at the upper part of the fitting hole 50e of the rotor 50 fitted to the drive shaft 35. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a centrifuge that rotates by exchanging a rotor.

  In a centrifuge for separating a biological sample or the like, the rotor, which is a sample holding container, is exchanged and used, so that the rotor is frequently attached and detached. For this reason, as the coupling between the rotor and the driving device is simpler, the convenience for the user is better. In order to realize this simplicity, it is necessary to use an attaching / detaching means that can be easily attached / detached instead of a fastening means using screws.

  7 and 8 show a typical mechanism for facilitating attachment / detachment.

  7 is a cutaway front view of a conventional centrifuge, and FIG. 8 is an enlarged detail view of part B of FIG. 7. Conventionally, a plurality of pins 53 are arranged behind the coupling hole 51 of the rotor 50 and coupled to each other. Similarly, a plurality of pins 1 are arranged on the upper surface side of the shaft 35, and a structure for transmitting the rotational force from the drive shaft 35 to the rotor 50 is adopted.

  Usually, a centrifuge with a rotational speed of up to about 20,000 rpm is operated in the atmosphere, so air exists in the rotor chamber 33 in which the rotor 50 is mounted. For this reason, when the rotor 50 rotates at high speed, the air in the rotor chamber 33 is agitated, and a pressure distribution is generated in the rotor chamber 33. The pressure distribution varies depending on the cross-sectional shape of the rotor 50, but when the pressure difference between the upper part and the lower part of the rotor 50 is large, a force that moves in the axial direction is generated. When the upper pressure P1 is lower than the lower pressure P2, the coupling force of the rotor 50 decreases due to buoyancy.

  Further, a slight gap is provided between the coupling hole 51 of the rotor 50 and the drive shaft 35, and the attachment / detachment is possible due to the gap. However, if the clearance is excessively large, the coupling of the rotor 50 is deteriorated, which causes a self-excited vibration during rotation.

For this reason, the weight 3 attached to the side surface of the drive shaft 35 so as to be slightly movable is provided. The weight 3 is pressed against an annular groove provided in the coupling hole 51 of the rotor 50 by centrifugal load generated by the rotation of the drive shaft 35. Tapered portions are provided at both ends of the annular groove in the axial direction, and by holding the weight 3 with the tapered portions, a force is generated that prevents the rotor 50 from moving in the axial direction during rotation. This axial movement restraining force prevents the rotor 50 from moving due to buoyancy and prevents self-excited vibration.
JP 2000-107643 A

  However, in the conventional configuration, if the rotor 50 is frequently attached and detached, wear may occur in the annular groove provided in the coupling hole 51 of the rotor 50. When the driving force is transmitted to the rotor 50 in a state where the annular groove is worn, there is a case where the restraining effect is insufficient with the axial restraining force generated by the centrifugal load generated by the weight 3 and self-excited vibration may occur. It was.

  The present invention has been made in view of the above problems, and an object thereof is to provide a centrifuge that can be easily attached to and detached from the drive shaft of the rotor while ensuring a sufficient coupling force to the rotating rotor. There is.

  In order to achieve the above object, the invention described in claim 1 includes a rotor that accommodates and holds a sample, and a drive device that rotationally drives the rotor, and the rotor has a fitting hole that fits the drive device. In the centrifugal separator formed and accommodated in the bottom of the fitting hole, the protrusion member for preventing idling is provided on the driving shaft of the driving device, and the outer periphery of the driving shaft is provided. An elastic seal member is provided, and a hole communicating with the outside is provided above the fitting hole of the rotor that is fitted to the drive shaft.

According to a second aspect of the present invention, in the first aspect of the present invention, a plurality of the holes are provided.

  According to the present invention, the elastic seal member is provided on the outer peripheral portion of the drive shaft, and the plurality of holes communicating with the outside are provided above the fitting holes of the rotor fitted to the drive shaft. Then, centrifugal force is generated in the elastic seal member, and the seal member comes into close contact with the fitting hole of the rotor. At this time, the space V formed above the elastic seal member is isolated from the space below the elastic seal member. During rotation, since the air inside the space V is discharged from the hole formed in the fitting hole of the rotor, the pressure in the upper space V isolated by the elastic seal member decreases. Due to the pressure difference with the outside, a coupling force is generated in the rotor in the direction of the rotation axis. This coupling force is generated by rotation, but when the rotor is rotating at a constant rotational speed, a large pressure fluctuation does not occur inside the rotor chamber, so that a constant coupling force can be generated stably. it can.

  When the rotor is attached / detached after the rotation is stopped, external air flows into the space V simultaneously with the rotation stop, so that the pressure difference is eliminated and no coupling force is generated. In addition, since the elastic seal member is restored to its original shape due to the absence of centrifugal force, it does not hinder the attachment / detachment of the rotor.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a cutaway front view of a centrifuge 30 according to the present invention. The illustrated centrifuge 30 includes a motor 34 and a rotor chamber 33. The motor 34 is a motor made of vibration-proof rubber or the like that absorbs vibration. It is supported by the support part 37. A drive shaft 35 of the motor 34 projects into the rotor chamber 33, and a rotor 50 is fixed to the upper end of the motor 34 via a fastening portion 36. A door 32 is installed in the upper portion of the rotor chamber 33, and the rotor 50 is attached and detached from above by opening the door 32.

  Next, the fastening part 36 is demonstrated based on FIG.2 and FIG.3.

  2 is a front sectional view of the fastening portion, and FIG. 3 is a partially enlarged sectional view of the elastic seal member mounting portion of FIG.

  The fastening portion 36 is largely composed of a cylindrical portion 2 and a tapered portion 4, and a circumferential groove 5 is formed on the upper end surface of the cylindrical portion 2. A plurality of cylindrical pins 1 are arranged in the groove 5 at equal intervals in a circular shape so as to be concentric with the groove 5. A weight groove 2a is formed on the side surface of the cylindrical portion 2, and a weight 3 is accommodated in the weight groove 2a. The weight 3 is fixed to the cylindrical portion 2 so as to be slightly movable in the radial direction via the weight pin 3a.

  A seal groove 6 is formed between the cylindrical portion 2 and the weight groove 2 a, and an elastic seal member 7 is mounted in the seal groove 6.

  The outer diameter d2 of the elastic seal member 7 mounted in the seal groove 6 is set slightly larger than the outer diameter d1 of the cylindrical portion 2 as shown in FIG.

  The elastic seal member 7 is made of an elastic body such as rubber, and its cross-sectional area is set to be about 80% with respect to the cross-sectional area of the seal groove 6. The elastic seal member 7 exhibits the same effect regardless of whether the cross-sectional shape is circular or rectangular, but the circular shape is most suitable because the sliding resistance needs to be reduced in order to easily attach and detach the rotor 50. . Usually, when the cross-sectional shape is circular, the simplest means is to use an industrial O-ring as the elastic seal member 7.

  Next, the structure of the rotor 50 will be described with reference to FIGS. 4 is a front sectional view of the rotor, and FIG. 5 is a sectional view taken along line AA of FIG.

  The rotor 50 is formed in a substantially truncated cone shape, and a plurality of tube holes 50 c for holding a sample to be centrifuged are formed radially with a predetermined angle with respect to the rotation shaft 60. A mounting hole 50e for mounting the rotor 50 to the drive shaft 35 is formed on the lower surface side of the rotor 50. The mounting hole 50e has a cylindrical hole 51 and a base from the cylindrical hole 51 to the lower surface. It is comprised from the taper surface 52 formed so that it might spread. A plurality of rotor pins 53 are arranged at equal intervals in a circular shape on the rear end face of the cylindrical hole 51 so as to be concentric with the cylindrical hole 51.

  As shown in FIG. 5, the cylindrical hole 51 has a plurality of communication holes 8 formed radially from the cylindrical hole 51 toward the radially outer side at the final end. Here, the inner diameter D of the cylindrical hole 51 is set to be slightly larger than the outer diameter d2 of the elastic seal member 7. The shape of the rotor 50 is not limited to that of the present embodiment.

  Next, the effect of this invention is demonstrated based on FIG.

  FIG. 6 is a schematic diagram showing centrifugal force and air flow when the rotor 34 is combined with the centrifuge 30 and the motor 34 generates rotational torque.

  When rotational torque is generated in the motor 34, centrifugal force is generated in the elastic seal member 7 provided in the fastening portion 36, and the elastic seal member 7 sticks to the cylindrical hole 51 and the seal groove 6 of the mounting hole 50e of the rotor 50. And sealed. At this time, the space V formed above the elastic seal member 7 is isolated from the space below the elastic seal member 7. During rotation, the air inside the space V is discharged from the communication hole 8 formed in the cylindrical hole 51 of the mounting hole 50e of the rotor 50, so that the pressure in the upper space V isolated by the elastic seal member 7 decreases. To do. Due to the pressure difference with the outside, the rotor 50 and the fastening portion 36 generate a coupling force in the direction of the rotation axis. This coupling force is generated by rotation, but when the rotor 50 is rotating at a constant rotational speed, a large pressure fluctuation does not occur inside the rotor chamber 33, so that a constant coupling force is stably generated. be able to.

  When the rotor 50 is detached after the rotation is stopped, external air flows into the space V through the communication hole 8 simultaneously with the rotation stop, so that the pressure difference is eliminated and no coupling force is generated. Further, since the elastic seal member 7 is restored to its original shape due to the disappearance of the centrifugal force and becomes smaller than the inner diameter D of the cylindrical hole portion 51 of the mounting hole 50e, there is no hindrance to the attachment / detachment of the rotor 50.

  In the conventional structure, since the elastic seal member 7 is not provided, the space V to be isolated is not formed, and the communication hole 8 that communicates radially outward from the space V does not exist, so the pressure inside the space V decreases. No fastening force in the direction of the rotation axis is generated.

It is a fracture front view of the centrifuge concerning the present invention. It is front sectional drawing of the fastening part of the centrifuge which concerns on this invention. It is a partial expanded sectional view of the elastic seal member attachment part of FIG. It is front sectional drawing of the rotor of the centrifuge which concerns on this invention. It is the sectional view on the AA line of FIG. It is a schematic diagram which shows the centrifugal force and the flow of air when a motor generate | occur | produces rotational torque in the centrifuge which concerns on this invention. It is a fracture front view of the conventional centrifuge. It is the B section enlarged detail drawing of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pin 2 Cylindrical part 2a Weight groove 3 Weight 3a Weight pin 4 Tapered part 5 Groove 6 Seal groove 7 Elastic seal member 8 Communication hole 30 Centrifuge 32 Door 33 Rotor chamber 34 Motor 35 Drive shaft 36 Fastening part 37 Motor support part 50 Rotor 50c Tube hole 50e Mounting hole 51 Cylindrical hole 52 Tapered surface 53 Rotor pin 60 Rotating shaft

Claims (2)

A rotor for accommodating and holding a sample, and a driving device for rotationally driving the rotor, a fitting hole for fitting with the driving device is formed in the rotor, and a protrusion member for preventing idling is formed at the bottom of the fitting hole In a centrifuge that is provided with a similar anti-spinning projection member on the drive shaft of the drive unit,
A centrifugal separator, wherein an elastic seal member is provided on an outer peripheral portion of the drive shaft, and a hole communicating with the outside is provided in an upper portion of a fitting hole of the rotor fitted to the drive shaft.   The centrifuge according to claim 1, wherein a plurality of the holes are provided.

Images