JPH0541786Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a vibration-proof bearing for a rotation drive device of a centrifuge that decomposes a sample by centrifugal force.

[Background of the idea]

Conventionally, a rotational drive device for a centrifuge rotating container has a fourth
As shown in the figure, in order to reduce the radial load on the bearing due to vibrations caused by the asymmetry of the rotating container, a thin shaft is inserted between the rotating container and the rotor, and the shaft's elasticity is utilized. However, since the rigidity of the shaft is low, the curvature of the shaft becomes large at the primary critical speed of the rotating system in the low speed range, and a rigidity higher than the limited one is required. Therefore, the load cannot be sufficiently reduced.

[Purpose of the invention] The purpose of the invention is to eliminate the drawbacks of the prior art described above, prevent vibrations at the primary critical speed in the low rotational speed range of this type of drive device, and reduce the radial load on the bearing. be.

[Summary of the idea]

This invention focuses on the fact that the part that fixes the bearing expands due to centrifugal force, and is devised so that the bearing acts in the low speed range and moves away from the rotating system in the high speed range. .

[Example of idea]

An embodiment of the present invention is shown in FIGS. 1 and 2. The rotating container 1 rotates at high speed on the crown 2. The crown 2 is connected via the shaft 4 and the rotor shaft 9,
Driven by a drive motor. The drive motor consists of a shaft case 5, an upper housing 6, a housing 7, a stator 10, and a rotor 11. A rotor 11 and an oil inlet 8 are fixed to a rotor shaft 9 and supported by bearings 12 and 13. Further, on the inner wall of the crown 2, a sleeve 15 is provided on the outer periphery of the anti-vibration bearing 3 as a movable piece that moves in the radial direction when the centrifugal force exceeds a predetermined value, that is, when the rotation speed exceeds a predetermined value.
is supported by an anti-vibration bearing 3 and a shaft case 5.

During low speed rotation, the crown and anti-vibration bearing are fixed with a sleeve 15 by pressing with a wave washer 14 as shown in FIG. 2a. Figure 3a shows the shape of the sleeve in this state viewed from above. During high-speed rotation, the sleeve 15 receives centrifugal force 16 outward, so it expands as shown in Figure 3b.
The taper at the bottom of the crown 2 pushes it upward and away from the anti-vibration bearing. At this point, the spring constant of the wave washer 14 is determined so that the primary critical speed (500 to 2000 rpm) has already been passed.

Instead of the wave washer 14 and sleeve 15 shown in FIGS. 1 and 2, for example, as another embodiment shown in FIG. 5, a movable piece movable in the radial direction by a predetermined centrifugal force By providing a leaf spring 17 on the inner wall of the crown 2 instead of the sleeve 15, the leaf spring 17 is provided in contact with the anti-vibration bearing 3 during low-speed rotation, and the leaf spring 17 is provided in place of the sleeve 15 during high-speed rotation.
The same effect can be obtained even if the vibration isolating bearing 7 is moved away from the anti-vibration bearing 3 by the centrifugal force applied thereto. As another embodiment, as shown in FIG. 6, an O-ring 18 is provided on the inner wall of the crown 2 instead of the sleeve 15 as a movable piece, so that it is in contact with the vibration-proof bearing 3 during low-speed rotation. The same effect can be obtained even if the O-ring 18 is pressed against the inner wall of the crown 2 and deformed due to the centrifugal force applied to the O-ring 18 during high-speed rotation, and the O-ring 18 is deformed and separated from the anti-vibration bearing 3. Can be done.

[Effect of idea]

According to the present invention, the anti-vibration bearing acts at low rotational speeds and does not act at high speeds, so it is possible to avoid the primary critical speed and rotate to high speeds. By making the shaft even thinner and lowering its rigidity, the load on the bearing can be reduced.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view showing an embodiment of the vibration-proof bearing of the drive device according to the present invention, Fig. 2 a and b are detailed views of the A part in Fig. 1, and Fig. 3 a and b are respectively the inventive vibration-proof bearing of the present invention. FIG. 4 is a sectional view of a conventional drive device, FIG. 5a and FIG. 6 are sectional views showing other embodiments of the present invention, and FIG. a
FIG. 1 is a rotating container, 2 is a crown, 3 is a vibration-proof bearing,
4 is a shaft, 5 is a shaft case, 6 is an upper housing, 7 is a housing, 8 is an oil inlet, 9 is a rotor shaft, 10 is a stator, 1
1 is a rotor, 12 and 13 are bearings, 14 is a wave washer, 15 is a sleeve, 16 is a direction of centrifugal force,
17 is a leaf spring, and 18 is an O-ring.

Claims (1)

[Scope of utility model registration request] A centrifuge having a motor, a shaft having one end fixed to the motor and surrounded by a shaft case, a crown provided at the other end of the shaft, and a rotating container that rotates integrally with the crown. , an anti-vibration bearing is disposed on the outer periphery of the shaft case surrounding the other end of the shaft, and a movable piece movable in a radial direction by centrifugal force is provided between the anti-vibration bearing and the crown. A vibration-isolating bearing for a centrifuge drive device, characterized in that the movable piece and the vibration-isolating bearing are in contact with each other during low-speed rotation, and the movable piece and the vibration-isolating bearing are out of contact during high-speed rotation.