JPH0448516Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a dynamic balance testing machine for small precision rotating parts.

Prior Art Figures 5 and 6 show the main parts of a conventional vertical dynamic balance tester.

In this figure, a rotating main shaft 32 having a specimen mount 30 and a pulley 31 at its upper end is supported by a body 34 by ball bearings 33, 33.
The body 34 is supported by two leaf springs 36, 36 protruding from a base plate 35. The rotating main shaft 32 is rotated by a motor (not shown) via a belt 37 and a pulley 31. At this time, centrifugal force is generated due to the unbalance amount of the specimen 38, and the leaf spring 36
The body 34 is displaced in the X direction with a deflection of
The amount of displacement is detected by the displacement sensor 39, and the amount of unbalance of the specimen 38 is determined.

Problems to be solved by the invention However, in the conventional configuration, vibrations occur due to unevenness of the ball rolling surfaces of the ball bearings 33, 33, fluctuations and vibrations in the tension of the belt 37, and non-uniformity in the bending rigidity of the belt 37. In high-precision testing machines, the level of this vibration is comparable to the amount of displacement due to unbalance, and there was a problem that the test accuracy was determined by the vibration level.

Therefore, it is an object of the present invention to provide a dynamic balance tester that reduces vibration noise that is an obstacle to improving test accuracy.

Means for Solving the Problems In order to achieve the above object, the present invention includes a rotating main shaft having a specimen mount at one end, and a rotating main shaft connected to the rotating main shaft through a radial hydrodynamic bearing and a thrust hydrodynamic bearing. A supporting body, a leaf spring that supports the body so as to be displaceable in one diametrical direction, a displacement sensor that detects the amount of displacement in one diametrical direction, and a connection between the other end of the rotating main shaft and the output rotating shaft of the motor. Equipped with a magnetic joint that connects without contact.

Operation When the output rotation shaft of the motor is driven, the rotation main shaft rotates following the output rotation shaft without contact due to the magnetic force of the magnetic coupling. At this time, dynamic pressure is generated by the radial and thrust hydraulic pressure bearings,
The rotating main shaft rotates while being supported by an oil film. Also, during this rotation, centrifugal force is generated due to the unbalanced amount of the specimen attached to the rotating main shaft, and the body is displaced in one diameter direction with the deflection of the leaf spring, and the amount of displacement is detected by the displacement sensor. , the amount of unbalance of the specimen is determined.

Embodiment FIG. 1 is a partially cutaway front view of a vertical dynamic balance tester according to an embodiment of the present invention.

In this figure, the rotating main shaft 1 is composed of a large diameter portion 1a and a small diameter portion 1b. The large diameter portion 1a is fitted into a bottomed bearing box 2 and supported vertically, and a specimen mounting base 3 is provided at the upper end of the large diameter portion 1a. The bearing box 2 is fitted into the body 4 and fixed with screws 5. Inner peripheral surface of body 4 and bearing box 2
The distance 6a between the outer circumferential surface and the large diameter portion 1 of the rotating main shaft 1 is
A passage 6d communicates with the gap 6b between the outer circumferential surface of a and the inner circumferential surface of the bearing box 2 and the gap 6c between the lower end surface of the large diameter portion 1a and the bottom surface of the bearing box 2, and between the gap 6a and the bottom surface 6b. , 6c are supplied with oil. A shield member 7 is provided on the outer peripheral surface of the small diameter portion 1b of the rotating main shaft 1 to prevent oil leakage. The lower end of the small diameter portion 1b is
It is connected to an output rotating shaft 9a of a motor 9 supported by a substrate 8 via a magnetic coupling 10. Specifically, the magnetic coupling 10 includes a first flange 10b provided at the lower end of the small diameter portion 1b by a screw 10a,
A plurality of poles 10c are arranged intermittently at equal pitches in the circumferential direction on this first flange 10b, a lower second flange 10d is provided on the upper end of the output rotation shaft 9a of the motor 9 with a screw 10j, and An upper second flange 10f provided on the lower second flange 10d by a collar 10i and a screw 10e.
A plurality of upper and lower permanent magnets 10g are provided intermittently at equal pitches in the circumferential direction on both second flanges 10d and 10f, and are individually opposed to each other with air gaps on both upper and lower (axially) end surfaces of each pole 10c. ,10
It is composed of h. Permanent magnets 10g and 10h, which are vertically opposed at each position, are opposite to each other with different polarities. The pole 10c is made of a high magnetic permeability material,
It has the same diameter as a 10g permanent magnet. The distance between the pole 10c and the permanent magnet 10g is set smaller than the distance between the pole 10c and the permanent magnet 10h, and the distance between the rotating main shaft 1, the specimen mounting base 3, the specimen 11, and the first
The weight of the flange 10b, pole 10c, and screw 10a is canceled to minimize the force generated in the axial direction (vertical direction).

As shown in FIG. 2, both sides of the body 4 are supported by screws 16 at one ends of leaf springs 12, 12, which are movable in one direction of the diameter of the body 4, that is, in the direction of the arrow X. The other end is attached to the substrate 8 with screws 17. Furthermore, a displacement sensor 13 is provided on one side of the body 4 to detect the amount of displacement in the direction of arrow X. Displacement sensor 13
A working transformer, moving coil type pick-up, etc. are used for this.

As shown in FIG. 3, a herringbone groove 14 as a radial dynamic pressure fluid bearing is formed on the outer peripheral surface of the large diameter portion 1a of the rotating main shaft 1, and as shown in FIG. A radial spiral groove 15 is formed on the end face as a thrust dynamic pressure fluid bearing. Note that the herringbone groove 14 and the radial spiral groove 15
may be provided on the bearing box 2, or may be provided on both the rotating main shaft 1 and the bearing box 2.

Next, the operation of the above configuration will be explained.

When the output rotation shaft 9a of the motor 9 is driven, the permanent magnets 10g, 10h are displaced in the circumferential direction with respect to the pole 10c.
The magnetic resistance of the magnetic path formed by the h-pole 10c and the flanges 10d, 10f changes, and the pole 10c gradually begins to rotate synchronously with the movement of the permanent magnets 10g, 10h. When the pole 10c rotates, that is, when the rotating main shaft 1 rotates, the specimen 1 attached in advance to the specimen mounting base 3 of the rotating main shaft 1 rotates.
Centrifugal force is generated by the unbalance amount of 1, and the body 4 is displaced in the X direction with the deflection of the leaf spring 12. The displacement amount is detected by the displacement sensor 13, and the unbalance amount of the specimen 11 is determined. .

By the way, when the rotating main shaft 1 rotates as described above, dynamic pressure is generated by the herringbone groove 14 and the radial spiral groove 15 along with this rotation, and the rotating main shaft 1 is moved by the oil film filling the outer space 6b and the outer space 6c. It is supported by the bearing box 2 in a non-contact manner in the radial and thrust directions. Here, since the hydrodynamic bearing using incompressible oil has great rigidity and damping effect, the rotating main shaft 1 rotates very stably, and its vibration is almost zero or very small. Therefore, test accuracy is significantly improved.

Although the embodiments have been described using a vertical dynamic balance tester, this dynamic balance tester can also be used as a horizontal type.

In addition, in this embodiment, a high magnetic permeability material was used for the pole 10c, but this was replaced with a permanent magnet.
If the permanent magnets of 0c, 10g, and 10h are arranged to face each other with different polarities, the power transmission performance of the magnetic joint 10 will be further improved.

Effects of the invention According to the dynamic balance tester of the present invention, the rotating main shaft is supported by a radial dynamic pressure fluid bearing and a thrust dynamic pressure fluid bearing, while a magnetic coupling is used to connect the rotating main shaft and the output rotating shaft of the motor. Since they are connected through contact, it is possible to reduce vibration noise, which is an obstacle to improving test accuracy.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway front view of a dynamic balance tester according to an embodiment of the present invention, FIG. 2 is a plan view of FIG. 1,
Figure 3 is a front view of the rotating main shaft, Figure 4 is a bottom view of Figure 3, Figure 5 is a partially cutaway front view of a conventional dynamic balance tester, and Figure 6 is a plan view of Figure 5. be. 1...Rotating main shaft, 4...Body, 9...Motor, 9a...Output rotating shaft, 10...Magnetic coupling, 1
0b...First flange, 10c...Pole, 10
d, 10f...second flange, 10g, 10h...
...Permanent magnet, 11...Specimen, 12...Plate spring,
13... Displacement sensor, 14... Radial dynamic pressure fluid bearing, 15... Thrust dynamic pressure fluid bearing.

Claims (1)

[Claims for Utility Model Registration] (1) A rotating spindle having a specimen mount at one end;
A body that supports this rotating main shaft via a radial hydrodynamic bearing and a thrust hydrodynamic bearing, a leaf spring that supports this body so as to be displaceable in one diametrical direction, and a displacement sensor that detects the amount of displacement in one diametrical direction. A dynamic balance tester comprising: a sensor; and a magnetic coupling that connects the other end of the rotating main shaft and the output rotating shaft of the motor in a non-contact manner. (2) The magnetic joint includes a first flange provided at the other end of the rotating main shaft, a plurality of poles provided intermittently in the circumferential direction on the first flange, and an output rotating shaft end of the motor. a second flange provided on the pole, and a second flange provided on each of the poles with air gaps provided on both end faces in the axial direction and facing each other.
A dynamic balance testing machine according to claim 1, comprising a plurality of permanent magnets provided on the flange.