JPS6237269B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a means for reducing friction loss in a rolling bearing for supporting a flywheel of a flywheel device having a vertical rotating machine structure.

A flywheel device generally stores electrical energy or mechanical energy as rotational inertia energy of a flywheel, and makes it available for use as electrical energy or rotational energy by a generator or mechanical converter when necessary. It is. Therefore, in the case of a flywheel device,
As means for improving the energy storage capacity, there are measures such as increasing the moment of inertia around the flywheel rotation axis or increasing the operating speed of the flywheel, and the latter is particularly effective. Therefore, in devices with an extremely large energy storage capacity, the diameter of the flywheel itself increases in order to obtain a large inertial effect from the above measures, and the weight accordingly becomes extremely large, sometimes reaching several hundred tons. . Therefore, in order to avoid an increase in the vibration of the rotating shaft due to shaft deflection due to the flywheel's own weight, or from the viewpoint of making effective use of the site area, it is advantageous for this type of flywheel device to have a vertical rotating shaft structure. In addition, in this type of device, in order to use the stored rotational inertia energy as effectively as possible and increase the energy fluctuation efficiency of the device, it is necessary to reduce energy loss due to friction in the bearing that supports the flywheel as much as possible. . Therefore, if the weight of the flywheel is large, most of the weight is supported by the magnetic attraction force of the electromagnet installed opposite the flywheel, thereby reducing energy loss due to frictional torque in the support bearing. suppressing the increase.

FIG. 1 is a sectional view showing a schematic configuration of a conventional flywheel device of this type. In Figure 1, 1
2 is a flywheel, 2 is an upper shaft of the flywheel 1, 6 is a lower shaft, and 4 is a rolling bearing for supporting the upper shaft 2, which is fixed to a housing 5. 6 is a rolling bearing for supporting the lower shaft 3, and is fixed to the frame 7. At the top of the flywheel 1, an electromagnet 8 is disposed in an upper bracket 9 with a slight gap therebetween. The excitation current supplied to the electromagnet 8 is controlled by detecting the thrust direction position of the flywheel 1 by a single displacement meter 12 attached to the upper bracket 9 and using the displacement signal.
A so-called constant suction force control method is used to generate a constant suction force regardless of changes in the gap between the two. The control circuit configuration of the electromagnet 8 at this time is shown in FIG. The displacement signal of the flywheel 1 from the displacement meter 12 becomes an input to the control circuit 14 through the amplifier 13, and the output signal of the control circuit 14 drives the excitation power supply 15 to control the excitation current to the electromagnetic coil 16. The flywheel 1 is rotatably housed in a container consisting of a housing 5, an upper bracket 9, a frame 7, and a lower bracket 10 so as to be rotatable by the rolling bearings 4 and 6. The upper shaft 2 is connected to a generator motor or the like through a coupling 11.

Next, the operation of the conventional flywheel device having such a configuration will be explained. Energy is stored by rotating the flywheel 1 by a generator connected to the coupling ring 11, converting it into rotational inertia energy of the flywheel 1, and storing the energy. is extracted and used as electrical energy by a generator motor, etc. On the other hand, the magnetic attraction force of the electromagnet 8 loads most of the total weight of the flywheel 1, and by reducing the thrust load on the rolling bearings 4 and 6, friction loss in the rolling bearings 4 and 6 is reduced. We are making reductions. However, the perpendicularity of the upper surface of the flywheel 1 facing the electromagnet 8 with respect to the center of the rotation axis inevitably involves a certain degree of error due to manufacturing accuracy, and it is difficult to process the upper surface at a right angle.
In order to increase the storage capacity, it is necessary to rotate the flywheel 1 at high speed, but this high speed rotation causes an uneven temperature rise in the flywheel 1.
In addition, even at operating speeds near the lateral vibration critical speed,
As shown in FIG. 3, the flywheel 1 is inclined with respect to the center of the rotation axis.
As a result, the gap formed between the electromagnet 8 and the upper surface of the flywheel 1 is not uniform on the circumference, resulting in a change in the gap Δg. The change Δg in the air gap due to the inclination of the flywheel 1 is determined by the displacement meter 12.
This is detected as a change in the thrust position of the flywheel 1. The magnitude of the magnetic attraction force of the electromagnet 8 is inversely proportional to the square of the air gap. Therefore, as the flywheel 1 rotates at an angle with respect to the center of rotation, the magnetic attraction force of the electromagnet 8 has a variable magnetic attraction force having a rotational speed component at that time according to a change in Δg. arise. As shown in FIG. 4, this fluctuating magnetic attraction force exhibits a characteristic in which the fluctuating magnetic semi-attraction force ΔF is superimposed on the magnetic attraction force F ₀ for the average air gap. The generation of such a fluctuating magnetic attraction force acts as a disturbance of a fluctuating load on the rolling bearings 4 and 6 that support the flywheel 1. This is not preferable in terms of securing the rotational performance and life of the rolling bearings 4 and 6, and in particular significantly affects the reduction in the life of the bearings.

This invention was made in order to eliminate the drawbacks of the conventional ones as described above, and includes at least two displacement meters for detecting the thrust position of the flywheel.
It is an object of the present invention to provide a flywheel device in which the fluctuating magnetic attraction force caused by the inclination of the flywheel is eliminated. FIG. 5 is a sectional view of a main part showing an embodiment of the present invention, and FIG. 6 is a block diagram showing a control circuit configuration of an electromagnet. In the figure, 1 to 11 are the same as those in FIG. 1, so their explanation will be omitted. Two displacement meters 12 are installed at symmetrical positions on the circumference of the flywheel 1. Each displacement meter 12
The displacement signal is input via an amplifier 13 to an averaging circuit 17 that performs arithmetic averaging of the displacement signal.
This averaged displacement signal is applied to the excitation power supply 15 via the control circuit 14 to control the excitation current to the electromagnetic coil 16.

Figure 5 shows the relative positional relationship with the displacement gauges 12 when the flywheel 1 is tilted with respect to the center of the rotation axis.
Assuming g ₁ and Δg ₂ , the difference between Δg ₁ and Δg ₂ becomes maximum when the inclination direction of the flywheel 1 matches the arrangement direction of the displacement meter 12, and becomes zero at a position rotated by 90 degrees from this position. . However, Δg ₁ , Δ
At the position where the difference in g ₂ is maximum, the displacement signals from the respective displacement meters 12 are averaged by the averaging circuit 17, and the drive signal to the excitation power source 15 is (Δg ₁ +Δ
g ₂ )/2. An excitation current proportional to this averaged signal (Δg ₁ +Δg ₂ )/2 is supplied to the electromagnetic coil 16. Since the averaged signal represents the average value of the air gap, fluctuations in the magnetic attraction force of the electromagnet 8 can also be effectively minimized.

As described above, according to the present invention, a plurality of displacement meters are provided to detect the thrust position of the flywheel, and the magnetic attraction force of the electromagnet is controlled using a signal obtained by averaging the displacement signals of the displacement meters, so that the flywheel It is possible to effectively reduce fluctuations in the magnetic attraction force due to the inclination of the flywheel, and it is also possible to extremely minimize fluctuations in the thrust load applied to the bearing that supports the flywheel, which has a remarkable effect on ensuring the life of the bearing. Therefore, a remarkable effect can be obtained in improving the safety, rotational performance, etc. of the flywheel device.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing a conventional flywheel device, Fig. 2 is a block diagram showing a conventional electromagnet control system, and Fig. 3 is a diagram showing the relative positional relationship with the electromagnet due to the inclination of the flywheel of the conventional device. FIG. 4 is a characteristic diagram showing changes in magnetic attraction force of the device shown in FIG. 3, FIG. FIG. 3 is a block diagram showing a control system of an electromagnet. In the figure, 1 is a flywheel, 2 is an upper shaft, 3 is a lower shaft, 4 is a rolling bearing, 8 is an electromagnet, 12 is a displacement meter, 13 is an amplifier, 14 is a control circuit, 15 is an excitation power supply, and 16 is an electromagnetic coil , 17 is an averaging circuit. Note that the same reference numerals in the drawings indicate the same or corresponding parts.

Claims (1)

[Claims] 1 A flywheel having an upper shaft and a lower shaft, a rolling bearing supporting the upper shaft, and an upper surface of the flywheel for magnetically attracting the flywheel to reduce the thrust load applied to the rolling bearing. An electromagnet disposed through a slight gap and at least two displacement meters for detecting displacement of the flywheel in the thrust direction are disposed at equal pitches on the circumference, and the electromagnet has the plurality of A flywheel device characterized in that an excitation current controlled by an averaged displacement signal from a displacement meter is supplied.