JPH07861A - centrifuge - Google Patents

Abstract

(57) [Abstract] [Purpose] In a centrifuge, which is a device that rotates several rotating bodies by exchanging them, if the portion connecting the rotating body and the driving device has an acute taper, the rotating body The purpose is to prevent the mating with the drive device and improve the handling. [Structure] The rotating body 2 is rotated by being combined with the rotating shaft 1, and the taper 5 of the connecting hole is placed on the taper 6 of the rotating shaft. By making the angle between the taper 5 of the hole and the taper 6 of the rotating shaft different, it is possible to prevent the coupling hole 3 from being stretched by centrifugal force, and to be stretched back to be mated when it falls and is stopped.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a coupling portion for transmitting drive of a device for exchanging and rotating several rotating bodies such as a centrifuge.

[0002]

_2. Description of the Related Art A conventional device has a structure such that ψ ₁ = ψ _{2 in} FIG. 1, and a coupling hole 3 at the center of a rotary member and a rotary shaft of a drive device have tapers 5 and 6, respectively. Rotation is transmitted by the frictional resistance of the surface. Therefore, in order to increase the frictional resistance, the taper angle of the rotary body side coupling hole 3 and the taper angle of the rotary shaft 1 are set to an acute angle of about 30 °, and they are manufactured to have the same angle.

[0003]

In the conventional structure, as shown in FIG.
As shown in, when the rotating body 2 rotates at high speed and the acupuncture points expand due to centrifugal force, but the taper angle expands without changing from before rotation (shown by the dotted line 9 in the figure), it rotates by the amount When the body 2 falls and stops its rotation and returns to its original spread, the frictional resistance of the taper causes the body 2 to fall back without slipping on the tapered surface. Therefore, there is a case where the rotary body 2 cannot be removed because the taper portion is press-fitted.

As shown in FIG. 3, the object 1 on the object 11
When 0 is attempted to move, generally, when the resultant force of P and F is R, and the angle θ formed by R and the normal has a relationship of tan θ ≦ Ms, no matter how large R is, the object does not start to slip. Here, Ms is a coefficient of static friction. Θs = tan ~ ¹ Ms giving this limit is said to static friction angle. The rotating body is generally made of aluminum alloy or titanium alloy, and the rotating shaft 1 is made of stainless steel or the like. In the case of dry friction, the friction coefficient with iron is about 0.82 for aluminum and about 0.59 for titanium.
It is known that the static friction angle is about 40 ° for aluminum and about 30 ° for titanium. Therefore, when the taper angle of the rotating shaft is about 80 ° or less, the rotating body 2 and the rotating shaft 1 are press-fitted without slipping when the elongation due to the centrifugal force returns. For this reason, there is also one in which the taper angle is widened to 80 ° or more to prevent this type of press fitting. But,
Conventionally used rotating bodies have a low speed so that press-fitting due to the extension of centrifugal force can be ignored, and the taper angle is an acute angle of about 30 °. Changing the taper angle only for a rotating body that rotates at a higher speed and receives a high centrifugal force (that is, a rotating body where the press-fitting cannot be ignored)
It will lose compatibility with the conventional rotating body,
There is a problem that the usable rotors are limited. Further, there is an example in which the press-fitting is reduced by periodically applying a lubricant to the taper portion in order to prevent dry friction and reduce the friction coefficient, but there is a problem of poor operability.

An object of the present invention is to solve the above-mentioned problems, to be compatible with a conventional rotating body, to have good operability, and to prevent press fitting between the rotating body and a rotary shaft.

[0006]

The above object is to make a difference between the taper angle of the coupling hole of the rotating body and the taper angle of the rotary shaft with respect to this tapered portion, and further to provide the rotary shaft with the centrifugal force on the outer circumference of the rotary shaft. This is achieved by providing a movable piece capable of pressing the coupling hole of the rotating body.

[0007]

[Function] The connecting hole and the rotating shaft configured as described above are not in complete contact with the tapered surface and are in linear contact, so even if the connecting hole expands due to centrifugal force, they are only in linear contact. When the rotation is stopped and the expansion of the coupling hole returns to its original state, the friction is small and the original position is restored, so it is difficult for the taper surface to press fit.

If the rotation is high, the movable piece on the outer circumference of the rotating shaft pushes the connecting hole from the inside by centrifugal force, so that the rotating shaft is inclined by the gap between the rotating shaft and the rotating body connecting hole. It is possible to avoid pressing into the tapered surface because the rotating body coupling hole does not undergo taper on the entire circumference of the tapered surface, but a portion of the tapered surface is received, the frictional force becomes lower, and it is easier to return to the original position. it can.

[0009]

FIG. 1 shows an embodiment of the present invention. The rotating body 2 in which the sample 4 is inserted is connected by inserting the connecting hole 3 into the rotating shaft 1 at the tip of the shaft 8 of the driving device. Rotating body 2
Is designed such that the taper 5 of the coupling hole rides on the taper 6 of the rotating shaft. The taper 5 angle ψ ₂ of the coupling hole is larger than the taper 6 angle ψ ₁ of the rotating shaft (ψ ₂ > ψ ₁ ), and only the portion having a large taper diameter is in line contact. Also,
A weight 7 that is movable in the radial direction is provided on a part of the rotary shaft 1, and is rotated together with the rotary body 1 to press the coupling hole 3.

Due to the rotation, the rotating body 2 receives a centrifugal force, and the coupling hole 5 expands in a radial direction. At this time, taper 5, 6
As described above, since the contact surface of is always in contact with only the portion with the large taper diameter, the friction is small even if the rotor 2 spreads at the high speed side and the rotating body 2 falls and then stops and the spread returns. It will not be pressed in. Further, since the weight 7 on the rotary shaft 1 presses the rotary shaft 1 into the coupling hole 3, the rotary body 2 is prevented from falling downward, which is more effective.

The same effect is obtained even in the case of dry friction in which there is no lubricant such as oil on the contact surface. ψ ₁ = 2
As a result of conducting the experiment at 8 °, ψ ₂ = 28 °, 29 °, 30 °, even if the rotating body was always pressed at ψ ₂ = 28 ° and could not come out, it was still pressed at ψ ₂ = 29 °, 30 °. I was able to pull it out.

[0012]

According to the present invention, since the taper angle of the rotating body and the taper angle of the rotating shaft for receiving it are made different, a movable piece for pressing the coupling hole by a centrifugal force is provided on a part of the rotating shaft. It is possible to provide a centrifuge having a rotating shaft that is compatible with a rotating body having a sharp angle and a rotating body that is not pressed into the rotating shaft, and is compatible with a rotating body having a low speed to a high speed.

Further, since it is not press-fitted even in a dry friction state, an oil lubricant is unnecessary and the operability can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view showing a connecting portion of a centrifuge according to the present invention.

FIG. 2 is an enlarged cross-sectional view showing an example of a conventional technique.

FIG. 3 is a schematic diagram illustrating friction.

[Explanation of symbols]

1 is a rotating shaft, 2 is a rotating body, 3 is a connecting hole of a rotating body, 4 is a sample, 5 is a taper of a connecting hole, 6 is a taper of a rotating shaft, 7 is a weight, 8 is a shaft, and 9 is a rotating joint. A hole, 10 is an object A, and 11 is an object B.

Claims (2)

[Claims] 1. A rotating body for containing a sample and a drive device for driving the rotating body, wherein the rotating body has a tapered coupling hole, and the driving device is coupled with the rotating body. In a centrifuge with a tapered coupling axis to
A centrifuge, wherein the coupling hole has a taper angle different from that of the coupling shaft, and a part of the outer periphery of the coupling shaft is provided with a member movable in the same direction as the centrifugal force. 2. The centrifuge according to claim 1, wherein a taper angle of the coupling shaft is larger than a taper angle of the coupling hole.