JP2014226659A - Centrifugal machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a centrifugal machine at an inexpensive price in which a rotor having a high capacity can be used, and a limit value of an imbalance quantity can be reduced.SOLUTION: A centrifugal machine comprises: a housing 2; a rotor 3; a rotor chamber 5 which has an opening 4 for taking in and out the rotor 3 provided in the housing, and accommodates the rotor 3; a door 7 for opening and closing the opening 4; a drive unit 6 which rotationally drives the rotor 3 and to which the rotor is detachably attached; a bearing member 10 having a spring action and an attenuation action existing between the rotor chamber 5 and the drive unit 6; and a movement restriction member 19 which restricts downward movement of the drive unit 6. It is so set that in a non-mounting state of the rotor 3, there is a vertical clearance between the movement restriction member 19 and the drive unit 6, and the contact and non-contact states of the movement restriction member 19 are differed by a self-weight of the rotor 3 mounted to the drive unit 6.

Description

  The present invention relates to a centrifuge using a centrifugal force generated by rotating a rotor by a drive device, and more particularly to a support structure of a drive device for countermeasures against rotor imbalance.

  A centrifuge is a device that uses centrifugal force generated by rotating a rotor at a high speed by a drive device.In a centrifuge, a sample is placed in a tube or a bottle, and the rotor is placed in a rotor. The sample held in the rotor is separated, purified, and the like by centrifugal force generated by being housed in the rotor chamber and rotating the rotor at high speed by a driving device such as a motor.

  The rotational speed of the centrifuge varies depending on the application, and a product group from low speed (maximum rotational speed is several thousand revolutions) to high speed (maximum rotational speed is 150,000 rpm) is provided according to the application.

  In general, the rotation shaft of a centrifuge drive device that rotates at 10,000 rpm or more reduces the bending rigidity of the rotation shaft, and has a natural frequency of bending on the lower speed side than the settable rotation speed of the rotor. A so-called elastic shaft is used to reduce the bearing load during high-speed rotation due to the imbalance of the entire rotor consisting of the imbalance remaining in the rotor itself and the imbalance of the sample.

  On the other hand, there are various types of rotors depending on the application to be separated. An angle rotor characterized by the fact that the hole for accommodating the sample and the rotation shaft of the driving device are at a fixed angle, and a bucket for accommodating the sample are used. There is a swing rotor characterized in that it is suspended from a rotor body and is swung from a vertical direction to a horizontal direction along with the rotation of the rotor to be in a horizontal direction. These various rotors are detachable from the drive device.

  The permissible rotational speed of the angle rotor varies depending on the application, and a product range from high speed to low speed is provided according to the application. A rotor with a high allowable rotational speed is small and has a small sample capacity and a low allowable rotational speed. The rotor is generally large and has a large sample capacity.

  Swing rotors, like angle rotors, are offered in a range of products from high speed to low speed depending on the application. However, swing rotors are complex in structure, and due to strength limitations, allowable rotation speeds are compared to angle rotors. In general, small product groups with low sample volume are provided.

  Here, the structure of a conventional centrifuge employing an elastic shaft, the structure of an angle rotor, and the structure of a swing rotor will be described with reference to FIGS. 6 is a front sectional view showing a conventional centrifuge, FIG. 7 is a front sectional view of an angle rotor, and FIG. 8 is a front sectional view of a swing rotor. However, the left half of FIG. 8 shows a stopped state and the right half shows a rotating state.

  First, the structure of a conventional centrifuge employing an elastic shaft will be described with reference to FIG. The centrifuge 1 accommodates the housing 2 and the rotor 3, and has a rotor chamber 5 having an opening 4 for inserting and removing the rotor 3 on the upper surface, a driving device 6 for driving the rotor 3, and an opening 4 for the rotor chamber 5. It consists of doors 7 and the like. The drive device 6 includes a motor, is configured to be rotatably supported by a bearing 8 and is driven by the motor, and is fixed to the lower surface of the rotor chamber 5 via a plurality of support members 10. The rotating shaft 9 is thin and flexible in order to reduce the bending rigidity. The support member 10 is made of a material having a spring action and a damping action such as a cylindrical vibration-proof rubber, and attenuates the vibration of the rotating shaft 9 due to the imbalance of the rotor.

  Next, the structure of the angle rotor will be described with reference to FIG. The angle rotor 11 has a substantially frustoconical outer rotor body. A plurality of holding holes 12 for sample containers are formed in the rotor body at equal angular pitches along the circumference of the rotor center. Is inserted with a sample container 13 into which a sample has been injected. A drive shaft hole 14A is formed in the lower center of the rotor body, and is attached to a rotation shaft of a drive device (not shown) during operation.

  Next, the structure of the swing rotor will be described with reference to FIG. The left half of FIG. 8 shows a stopped state and the right half shows a rotating state. The swing rotor 15 includes a rotor body 16 and a plurality of buckets 17 and the like disposed at an equal angular pitch along the circumference of the center of the rotor body 16. A drive shaft hole 14 </ b> B is formed in the lower center of the rotor body 16. The rotor body 16 is provided with a bucket pin 18, and the bucket 17 is suspended from the bucket pin 18. When the rotation is stopped, the bucket 17 suspended in the vertical direction due to gravity swings in the horizontal direction due to the centrifugal force generated by the rotation of the rotor body 16.

  In the conventional centrifuge of FIG. 6 that employs an elastic shaft as the rotating shaft described above, when the rotational speed of the rotor 3 is increased, resonance occurs when passing the natural frequency of bending given to the low speed region, and Due to the imbalance of the rotor 3, the shaft 9 vibrates with the lower base portion 21 as a fulcrum so that the shaft 9 swings greatly toward the rotating shaft tip 22. Along with the vibration of the rotating shaft 9, the driving device 6 receives the reaction force of the rotating shaft 9 and vibrates not a little with the support member 10 as a fulcrum. Due to the vibration of the driving device 6, the amplitude of the rotating shaft 9 is suppressed, and the damping effect of the support member 10 of the driving device 6 has an effect of reducing the amplitude of the rotating shaft 9.

  In general, at the time of resonance, it is known that the cylindrical anti-vibration rubber (support member 10) uses a material having a large loss factor (loss factor) to increase the attenuation and reduce the resonance magnification. Further, it is known that the loss coefficient of the cylindrical vibration-proof rubber is increased by increasing the rubber hardness.

  However, increasing the hardness of the cylindrical anti-vibration rubber increases the spring constant of the cylindrical anti-vibration rubber, which makes it difficult for the drive device to vibrate, thus reducing the effect of suppressing the rotation of the rotating shaft during resonance, There was a problem that the amplitude of the rotating shaft was increased. In particular, the swing rotor has a structure that swings the bucket in the horizontal direction, so the position of the center of gravity is high, and the distance between the position of the center of gravity of the swing rotor and the rotating shaft support portion of the drive device becomes long. There is a problem that the plastic shaft is deformed beyond the elastic region of the rotational shaft, and the rotational shaft is bent.

  On the other hand, if a cylindrical anti-vibration rubber with a small spring constant is used to reduce the amplitude of the rotating shaft at the time of resonance, the deformation of the cylindrical anti-vibration rubber increases due to the dead weight of the rotor, and the gap between the rotor bottom and the rotor chamber becomes large. There was a problem that the two became in contact in the worst case. In particular, large-capacity angle rotors have a greater weight than other rotors and have a wider bottom surface. Therefore, in addition to the downward movement of the rotor due to the deformation of the cylindrical anti-vibration rubber, the swing of the rotating shaft during resonance Due to the inclination of the rotor, the bottom surface of the rotor and the rotor chamber are in contact with each other.

  In view of these problems, Patent Document 1 below proposes to use a support member and a suspension made of a wire, a piano wire or the like in combination for mounting the drive device.

Japanese Patent No. 3968960

  In order to solve the above problem, in the conventional centrifuge, the spring constant of the support member is increased to reduce the deformation of the support member due to the weight of the rotor, and the limit value of the rotor imbalance amount is reduced for resonance. Thus, a method of reducing the amplitude of the rotation shaft of the driving device has been taken. However, if the limit value of the imbalance amount is reduced, in order to reduce the residual imbalance amount of the rotor itself, the rotor must be processed more precisely, which takes time and increases the cost. It was. In addition, if the limit value of the sample imbalance amount is reduced, the mass of the sample inserted into the rotor must be strictly controlled, and there is a problem that the user's usability deteriorates.

  In addition, in a conventional centrifuge, a rotor whose weight is large cannot be used so that the spring constant of the support member is reduced, the amplitude at the time of resonance is reduced, and the deformation of the support member due to the weight of the rotor is not increased. There have also been some ways to limit it. However, when the dead weight of the rotor is limited, there is a problem that a large capacity rotor such as a large capacity angle rotor cannot be used, and user convenience is deteriorated.

  Further, in Patent Document 1, a method for reducing the limitation of the rotor imbalance amount and the rotor's own weight is provided by using a support member and a hanging tool made of a wire, a piano wire, or the like in combination for attaching the driving device. However, the centrifuge described in Patent Document 1 has a problem in that the mechanical parts of the lifting tool are complicated and the number of parts is large, and it takes time to adjust the length of the lifting tool, which increases the cost. .

  The present invention has been made in view of such a situation, and an object of the present invention is to provide an inexpensive centrifuge that can use a large-capacity rotor and that reduces the limit value of the imbalance amount.

One embodiment of the present invention is a centrifuge. The centrifuge includes a housing, a rotor, a rotor chamber that houses the rotor, a driving device that rotationally drives the rotor, a support member that supports the driving device on the housing, and a lower portion of the driving device. A movement restriction member that restricts movement to
When the rotor is not mounted, there is a vertical gap between the movement limiting member and the driving device or the housing member, and the movement is performed by the weight of the rotor mounted on the driving device. The contact member and the non-contact state of the restriction member are different.

  In the above aspect, the movement restricting member may be provided below the driving device.

  In the above aspect, the movement restricting member may be provided on the housing side.

  In the above aspect, the movement restricting member may be provided on the driving device side.

  The said aspect WHEREIN: It is good in the structure which the force of the expansion | extension direction is added to the said supporting member with the weight of the said rotor.

  In the above aspect, the movement restricting member may be a vibration isolating component having a spring action and a damping action.

  In the above aspect, the movement limiting member may be a friction damper having a spring and a damping mechanism.

  It should be noted that any combination of the above-described constituent elements, and those obtained by converting the expression of the present invention between methods, systems, and the like are also effective as an aspect of the present invention.

  According to the present invention, there is a vertical gap between the movement limiting member and the driving device or the member on the housing side, and the movement limiting is performed so that the contact and non-contact states of the movement limiting member differ depending on the weight of the rotor's own weight. By arranging the members, it is possible to limit the amount of deformation of the support member of the drive device when the rotor is mounted and when it is rotating. A centrifuge with a reduced value can be realized at low cost.

BRIEF DESCRIPTION OF THE DRAWINGS It is embodiment of the centrifuge which concerns on this invention, Comprising: The front sectional view which shows the centrifuge at the time of rotor mounting. The front sectional view when similarly mounted with a swing rotor. Similarly, a front sectional view when a large-capacity angle rotor is mounted. It is a movement limiting member used in the embodiment, wherein (A) to (D) are front views showing specific examples of the vibration isolating member, and (E) is a front sectional view showing a friction damper. The front sectional view which shows other embodiment of the centrifuge which concerns on this invention. Front sectional view showing a conventional centrifuge. The front sectional view of an angle rotor. The front sectional view of a swing rotor.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same or equivalent component, member, process, etc. which are shown by each drawing, and the overlapping description is abbreviate | omitted suitably. In addition, the embodiments do not limit the invention but are exemplifications, and all features and combinations thereof described in the embodiments are not necessarily essential to the invention.

  The structure of a centrifuge (centrifuge) according to an embodiment of the present invention will be described with reference to FIGS.

  A centrifuge (centrifuge) 1 includes a housing 2, a rotor 3, a rotor chamber 5 having an opening 4 for inserting and removing the rotor 3 on an upper surface, a driving device 6 for driving the rotor 3, and an opening of the rotor chamber 5. It is comprised from the door 7 etc. which open and close the part 4. FIG. The housing 2 has an outer frame 2a on the outer side and an intermediate frame 2b fixed at an intermediate position on the inner side, and the bottom surface of the rotor chamber 5 is fixedly supported by the intermediate frame 2b. A central portion of the intermediate frame 2 b is a duct-shaped recess 30 that houses (encloses) the driving device 6. Cooling air for cooling the drive device 6 is passed through the duct-shaped recess 30.

  The drive device 6 includes a motor, is configured to be rotatably supported by a bearing 8 and is driven by the motor, and the like. The drive device 6 is fixed to the lower surface of the bottom surface portion 5a of the rotor chamber 5 via a plurality of support members 10. Has been. The rotating shaft 9 is a so-called elastic shaft, and is thin and flexible in order to reduce bending rigidity. The support member 10 is composed of a material having a spring action and a damping action such as an anti-vibration rubber or a friction damper combining a coil spring and a friction member. Here, in order to suppress the amplitude of the rotating shaft 9 at the time of resonance, the spring constant of the support member 10 is small.

  Below the bottom surface of the drive device 6 (usually a metal surface), a movement limiting member 19 is fixed to the inside of the bottom surface of the duct-shaped recess 30 formed in the intermediate frame 2b. Similar to the support member 10, the movement restricting member 19 is composed of a member having a spring action and a damping action such as a vibration isolating rubber and a friction damper. A specific configuration of the movement limiting member 19 will be described later with reference to FIG.

  There is a gap in the vertical direction between the movement limiting member 19 and the bottom surface of the driving device 6, and the gap is larger than the amount of deformation of the support member 10 when the swing rotor is mounted, and when a large capacity angle rotor having a large weight is mounted. It is set smaller than the deformation amount of the support member 10.

  FIG. 2 shows a case where a swing rotor is mounted in the present embodiment. When the swing rotor 15 is mounted (mounted) on the rotating shaft 9 of the driving device 6, the support member 10 is deformed by the weight of the swing rotor 15. The drive device 6 moves downward with the deformation of the support member 10, but the clearance provided between the movement limiting member 19 and the bottom surface of the drive device 6 is secured because it is larger than the deformation amount of the support member 10. The member 19 is not contacted. For this reason, at the time of resonance, the drive device 6 can vibrate with the support member 10 as a fulcrum, and the swing of the rotating shaft 9 can be suppressed.

  FIG. 3 shows a case where a large capacity angle rotor is mounted in the present embodiment. When the large-capacity angle rotor 20 is mounted on the rotating shaft 9 of the driving device 6, the support member 10 is deformed by the weight of the large-capacity angle rotor 20. With the deformation of the support member 10, the driving device 6 moves downward, the clearance provided between the movement limiting member 19 and the bottom surface of the driving device 6 is eliminated, and the driving device 6 contacts the movement limiting member 19. As a result, the downward movement of the driving device 6 is restricted, and a sufficient gap is ensured between the bottom surface of the large-capacity angle rotor 20 and the rotor chamber 5.

  The driving device 6 is restrained by contacting the movement restricting member 19. However, the restraining to the driving device 6 is only a downward movement restriction and a frictional force in the horizontal direction, and the restraining force is small. Further, since the movement restricting member 19 is composed of an anti-vibration rubber having a spring action and a damping action, a friction damper, or the like, the drive device 6 can vibrate smoothly during resonance due to the spring action of the movement restricting member 19. Due to these actions, contact between the bottom surface of the large-capacity angle rotor 20 and the rotor chamber 5 at the time of resonance can be prevented.

  According to the present embodiment, the following effects can be achieved.

(1) The imbalance limit value of the rotor 3 is reduced by providing a gap between the movement limiting member 19 and the bottom surface of the driving device 6 so that the contact and non-contact states are different depending on the weight of the rotor 3. It is possible to use a large-capacity rotor that has a large weight.

(2) By using a cylindrical vibration-proof rubber or a friction damper for the movement restricting member 19, the cost of the movement restricting member can be reduced.

  4A to 4E are specific examples of the movement limiting member 19 having a spring action and a damping action, respectively. FIG. 4A shows a vibration isolating component (elastic component) in which metal plates 32a and 32b are fixed to the upper and lower end surfaces of the columnar vibration isolating rubber 31 and a mounting bolt 33 is integrated with the lower metal plate 32b. It fixes using the volt | bolt 33 inside the bottom face of the duct-shaped recessed part 30 formed in the intermediate | middle frame 2b of FIG. In this case, when the drive device 6 is lowered, the metal plate 32 a on the upper end surface comes into surface contact with the bottom surface (metal surface) of the drive device 6. Since the metal surfaces are in contact with each other, there is little friction in the horizontal direction and the movement of the driving device 6 in the horizontal direction is not hindered.

  4 (B) and 4 (C), the upper part of the anti-vibration rubber 31 is formed in a spherical or convex shape, a metal plate 32b is fixed to the lower end surface of the anti-vibration rubber 31, and the mounting bolt 33 is integrated with this. This is an anti-vibration component (elastic component). When the driving device 6 is lowered, the spherical or convex surface portion of the vibration isolating rubber 31 is in point contact with the bottom surface of the driving device 6. For this reason, the effect of reducing the friction in the horizontal direction and not hindering the movement of the driving device 6 can be obtained.

  FIG. 4D shows an elastic part in which a metal ball 35 is embedded in the upper surface of the vibration-proof rubber 31, a metal plate 32 b is fixed to the lower end surface of the vibration-proof rubber 31, and a mounting bolt 33 is integrated therewith. When the drive device 6 is lowered, the metal ball 35 makes point contact with the bottom surface (metal surface) of the drive device 6. For this reason, the effect of reducing the friction in the horizontal direction and not hindering the movement of the driving device 6 can be obtained.

  In FIG. 4E, a metal coil spring 42 is housed in a cylindrical vibration-proof rubber 41, both ends of the cylindrical vibration-proof rubber 41 are closed with metal plates 43a and 43b, and mounting bolts 33 are integrated with the metal plate 43b. It is a friction damper (vibration-proof pipe). Cylindrical anti-vibration rubber 41 constitutes a damping mechanism for damping the vibration of the spring 42. In this case, the drive device 6 can be vibrated smoothly during resonance by the spring action of the coil spring 42, and the amplitude of the rotating shaft can be suppressed.

  FIG. 5 shows another embodiment of the centrifuge according to the present invention. In this case, the movement limiting member 19 is fixed to the bottom surface of the driving device 6. Other configurations are the same as those of the above-described embodiment.

  Also in the embodiment of FIG. 5, when the swing rotor (light rotor) is mounted, the movement restricting member 19 on the driving device side and the inner bottom surface of the duct-shaped recess 30 formed in the intermediate frame 2b are not in contact with each other. When mounting the rotor (heavy rotor), the movement limiting member 19 and the inner bottom surface of the recess 30 can be set to contact each other. As a result, the same effect as that of the above-described embodiment can be obtained.

  The present invention has been described above by taking the embodiment as an example. However, it is understood by those skilled in the art that various modifications can be made to each component and each processing process of the embodiment within the scope of the claims. By the way. Hereinafter, modifications will be described.

  The movement restricting member 19 is arbitrary as long as it can restrict the downward movement of the driving device 6, and the movement restricting member 19 may be provided on the side surface of the driving device 6 or below the bottom surface of the rotor chamber 5. Further, two or more movement restriction members 19 may be provided.

DESCRIPTION OF SYMBOLS 1 Centrifuge 2 Case 3 Rotor 4 Opening part 5 Rotor chamber 6 Drive device 7 Door 8 Bearing 9 Rotating shaft 10 Support member 11 Angle rotor 12 Holding hole 13 Sample container 14 Drive shaft hole 15 Swing rotor 16 Rotor body 17 Bucket 18 Bucket Pin 19 Movement limiting member 20 Large-capacity angle rotor 21 Lower base portion 22 Rotating shaft tip

Claims (7)

A housing,
A rotor,
A rotor chamber containing the rotor;
A driving device for rotationally driving the rotor;
A support member for supporting the driving device on the housing;
A movement restriction member for restricting the downward movement of the driving device,
When the rotor is not mounted, there is a vertical gap between the movement limiting member and the driving device or the housing member, and the movement is performed by the weight of the rotor mounted on the driving device. A centrifuge characterized by different contact and non-contact states of the limiting member.   The centrifuge according to claim 1, wherein the movement restricting member is provided below the driving device.   The centrifuge according to claim 1 or 2, wherein the movement restricting member is provided on the housing side.   The centrifuge according to claim 1 or 2, wherein the movement restricting member is provided on the drive device side.   The centrifuge according to any one of claims 1 to 4, wherein a force in an extending direction is applied to the support member by a weight of the rotor.   The centrifuge according to any one of claims 1 to 5, wherein the movement limiting member is a vibration-proof component having a spring action and a damping action.   The centrifuge according to any one of claims 1 to 5, wherein the movement limiting member is a friction damper having a spring and a damping mechanism.

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