JPH0324316A - Bearing device - Google Patents

Abstract

PURPOSE:To operate in an adequate viscosity by controlling a voltage with application of an electric field to an electrode disposed in a shaft and a bearing so as to control a viscosity of an electroviscous fluid flowing between the shaft and the bearing. CONSTITUTION:A space between a shaft 1 and a bearing 2 is filled with an electroviscous fluid 3 as lubricating oil. A power source 4 is connected to the shaft 1 and bearing 2 serving as an electrode. The shaft 1 and the power source 4 are connected in a rotatable manner. The viscosity of the electroviscous fluid 3 is varied dependently on the output voltage of the power source (voltage controller) 4. There is provided a sensor for detecting a rotational speed of the shaft, a temperature of the electroviscous fluid, and the like, thus controlling the output voltage of the voltage controller on the basis of the detected signal. Therefore, a viscous resistance of a flow in the space between the shaft and the bearing can be freely controlled, and a load capacity and the like can be controlled at real time, thus enabling an operation in a viscosity adequate for a rotational speed.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to bearing devices such as hydrostatic bearings and sliding bearings, and in particular to bearing devices that maintain a constant bearing clearance in response to changes in load or any type of bearing device. The present invention relates to a bearing device in which a clearance can be set.

[Conventional technology]

In conventional bearing devices, Japanese Patent Publication No. 5341853 and Practical Performance of Lubricity New Edition - Tribology Series 2 Kazuyuki Shobo. 19
80, pages 167 to 169, in order to avoid contact between the shaft and the bearing at the start of operation or at low speeds, or poor lubrication, the bearing must be operated as a hydrostatic bearing for a certain period of time from the start of operation. The company then adopted a method of switching to hydrodynamic bearings.

In addition, regarding the relationship between the temperature and viscosity of lubricating oil, the new edition of Practical Performance of Lubricants - Tribology Series 2, Kouserifusa, 1
980, pages 73 to 75 and pages 49 to 5
As described on page 2, the viscosity decreases as the temperature rises, so a viscosity index improver is added to the lubricating oil to suppress changes in viscosity due to temperature changes.

In addition, as shown in Japanese Patent Application Laid-Open No. 60-150950,
The supply pressure of fluid supplied to the bearing was controlled by a pressure control valve in accordance with changes in the bearing clearance. Also,
The aperture resistance was changed using piezo elements, diaphragms, etc.

[Problem to be solved by the invention]

The above-mentioned conventional technology used a static pressure bearing to avoid direct contact between the shaft and the bearing during low-speed operation such as when starting operation, but the device for static pressure was complicated. Additionally, by adding additives such as viscosity index improvers, lubrication performance has been improved by suppressing changes in the viscosity of lubricating oil due to environmental temperature and temperature differences between the start of operation and steady operation. However, with these conventional technologies, only a lubricant that satisfies certain operating conditions is selected, and the viscosity of the lubricant within the bearing cannot be freely changed, so it is not compatible with a wide range of operating conditions. In addition, the method of controlling the supply pressure with a pressure control valve not only requires an expensive pressure control valve at the input, but also
Currently, the response of the valve is poor, so it is at most 50~loO.
It is possible to control only up to about Hz. In addition, a method in which the aperture is mechanically controlled using a diaphragm or the like has a complicated structure.

An object of the present invention is to provide a bearing device that can effectively control load capacity or bearing clearance in a simpler manner by controlling the viscosity of lubricating oil according to the shaft rotational speed, transfer speed, or lubricating oil temperature. The purpose is to [Means for Solving the Problems] In order to achieve the above object, the present invention uses an electrorheological fluid whose viscosity changes depending on an electric field as a lubricant for a bearing device, and a method for applying an electric field to the electrorheological fluid. Electrodes are provided to sandwich the electrorheological fluid, and a rotational speed or a moving speed of the support supported by the bearing device is detected by a rotation sensor or a speed sensor. The viscosity of the electrorheological fluid is changed by applying an electric field between electrodes provided on the bearing device in accordance with the detection signal.

In the sliding bearing, a thermometer for measuring the temperature of the electrorheological fluid is provided on the sliding bearing, and an electric field is applied between electrodes provided on the sliding bearing in accordance with the temperature or a signal corresponding to the temperature. Accordingly, the viscosity of the electrorheological fluid is changed.

Hydrostatic bearings use electrorheological fluid as the working fluid and are designed to apply an electric field near the throttle in the fluid supply section, thereby controlling the viscosity of the fluid passing through the throttle and controlling the throttle resistance. It is. By dividing the bearing gap (bearing surface) into a plurality of segments and changing the electric field independently for each segment, the viscosity of the electrorheological fluid in that part is controlled.

A control loop is configured to detect the bearing clearance with a displacement meter, etc., and control the electric field based on the deviation between this and the target value, changing the viscosity of the electrorheological fluid in that area, and changing the flow resistance. This is what I did.

[Effect]

Electrorheological fluids have the property that when an electric field is applied, their viscosity increases in response to the strength of the electric field, and when the electric field is removed, they return to their original viscosity. Therefore, the viscosity of the electrorheological fluid changes due to an external electric field, and therefore the resistance to flow changes.

In a bearing device, if an electrorheological fluid is used and the viscosity is controlled by applying an external electric field, the flow resistance changes and the performance of the bearing device can be freely controlled. That is, when an electric field is applied between the electrodes provided to sandwich the electrorheological fluid on the bearing surface, the viscosity of the electrorheological fluid changes depending on the strength of the electric field. It is possible to measure the moving speed or the temperature of the electrorheological fluid, change the viscosity of the electrorheological fluid based on this information, and control the bearing load capacity and bearing clearance. Hydrostatic bearings have a throttle that supplies fluid and a bearing gap (bearing surface) that generates pressure and supports the load.If the resistance passing through the throttle increases, the pressure on the downstream side, that is, in the bearing gap, decreases. load capacity decreases,
Furthermore, if the resistance of the bearing gap is increased while the resistance of the throttle is kept constant, the pressure at the throttle outlet will increase and the load capacity will increase.

By creating a structure that allows an electric field to be applied independently to the orifice and the bearing gap, which are the components of a hydrostatic bearing, and controlling the external electric field appropriately according to the load, the bearing gap can be adjusted against load fluctuations. Free control is possible, such as keeping it constant or setting the bearing clearance to an arbitrary size. Furthermore, by dividing the bearing clearance (on the bearing surface) into a plurality of segments and applying an electric field to each segment independently, the bearing clearance of each segment can be controlled, and the posture of the shaft can also be controlled.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. FIG. 1 is a diagram showing an example of application to a journal bearing.

In this figure, there is an electrorheological fluid 3 as a lubricating oil between a shaft 1 and a bearing 2, and a power source 4 for applying an electric field to this electrorheological fluid 3 connects the shaft 1 and the bearing 2, which also serves as an electrode.
Of these, the shaft 1 and the power source 4 are rotatably connected. According to the invention, by changing the output voltage of the power supply 4. The viscosity of the electrorheological fluid 3 as im lubricant can be varied within the bearing.

FIG. 2 is a diagram showing an embodiment in which the structure of the electrodes is changed.

In FIG. 2, 5 is a shaft, 6 is a bearing, 8 is an electrorheological fluid, and 9 is a power source. Further, the bearing 6 has an electrode 6a
, 6b and #@edge bodies 7a, 7b. Insulator? Electrodes 6a, 6 electrically insulated by a, 7b
An electric field can be applied to the electrorheological fluid by connecting an electric current g9 to b and applying a voltage, and by changing the output voltage of the power source 9, the viscosity of the electrorheological fluid can be changed. At this time, it is desirable that the thickness of the insulators 7a and 7b be larger than the bearing clearance, and that the shaft 5 be a good electrical conductor.

FIG. 3 is a diagram showing an example in which the present invention is applied to a reciprocating plane bearing. 10 is a shaft which is a supported body; 11 is a bearing;
12 is an electrorheological fluid, and 13 is a power source. axis IO
and bearing 11 are used as electrodes, and when a power source 13 is connected to these and a voltage is applied, an electric field is generated between shaft 10 and bearing 11, and ? ! The electrorheological fluid, which is J lubricant, has a viscosity that corresponds to this electric field.

Figure 4 shows an example of application to a tailing pad bearing, in which each pad has an independent power supply. In this figure, 14 is the axis, 15a, 1 5 b, 1
5 c and 1 5 d are pads, ↓ 6 is an electrorheological fluid, and 17 a, 17 b, 17 c, and 17 d are power supplies. One end of the power supplies 17a, 17b, 17c, 17d is rotatably connected to the shaft 14, and the other end is connected to each pad 15a, 1
5b, 15c, and 15d. Each electric train] 17a
, 17b, 17c, 17d, each pad 15a, 1
By applying a voltage between 5b, 15c, 15d and the shaft 14, the electrorheological fluid 16 between each bearing becomes viscous in accordance with each electric field. Therefore, the viscosity of the electrorheological fluid 16 can be changed for each pad depending on the shaft support conditions and the like. Also, as a matter of course, the fil sources 17a, 17b,
The viscosity of the entire electrorheological fluid can also be changed by combining 17c and 17d and connecting them between the pad holder 15 and the shaft 14.

FIG. 5 is a diagram showing an embodiment applied to a thrust bearing. In this figure, a power source 21 is connected to the bearing runner 18 and the pad 19, and a voltage is applied between the pad 19 and the bearing runner 18 to generate an electric field. By generating this, the viscosity of the electrorheological fluid 20 during this period can be changed.

FIG. 6 is a diagram showing an example of a sliding bearing that detects the temperature of electrorheological fluid as lubricating oil and changes the viscosity by changing the electric field applied to the electrorheological fluid accordingly. In this figure, 22 is a shaft, 23 is a bearing with an insulator 24 provided inside an electrode 25, and 26 is an electrorheological fluid.

The insulator 24 is connected to the power source 3 when the shaft 22 and the electrode 25 are in contact with each other.
This is to prevent 0 from ending too soon. In this example,
The temperature is detected by a temperature sensor 27, and based on this detection signal, a controller 28 controls the voltage of a power source 29 applied between the shaft 22 and the electrode 25, thereby controlling the viscosity of the electrorheological fluid 26. .

According to this embodiment, the viscosity of the electrorheological fluid 26 as a lubricating oil can be controlled in accordance with the temperature within the bearing. FIG. 7 is a diagram showing an embodiment in which the viscosity of the electrorheological fluid in the bearing is changed depending on the speed of the shaft. In this figure, 30
is a shaft, 31 is a bearing which is connected to an insulator 33 and an electrode 32, and 34 is an electrorheological fluid. The rotational speed of the shaft 30 is detected by a rotational speed detector 35, and based on this detection signal, a controller 36 controls the voltage, that is, the electric field, applied between the shaft 30 and the electrode 32, thereby controlling the viscosity of the electrorheological fluid 34. According to this embodiment, the viscosity of the electrorheological fluid 34 as the lubricating oil in the bearing can be controlled according to the degree of rotation of the shaft 30. Note that the present invention is a sliding bearing that uses lubricating oil, and any structure may be used as long as it can apply an electric field. Next, an example in which the present invention is applied to a hydrostatic bearing will be described.

FIG. 8 shows a general configuration of a hydrostatic bearing. The fluid supplied with pressure Ps is subjected to throttling resistance at the throttle 40, and has a pressure P at the throttle outlet. Furthermore, when the fluid passes through the bearing gap 41, it is discharged to the outside (pressure pa) while being subjected to viscous resistance. The pressure distribution is as shown in FIG. Here, the load capacity of the bearing is the value obtained by integrating the pressure p in the bearing gap over the bearing area.6 When the load W increases, the bearing gap 41 decreases, the resistance of the fluid flowing through the gap increases, and as a result, P+ reaches PIC. As shown by the broken line in FIG. 9, the pressure distribution becomes higher than the pressure distribution shown by the solid line, and the load capacity increases to balance the increased load. The present invention achieves the operating principle of the above-mentioned hydrostatic bearing by using an electrorheological fluid and an electric field generating device that can generate electricity independently for each element. FIG. 10 shows an embodiment of the present invention. An electrode 43 is provided around the diaphragm, and a voltage controller 44 applies an electric field to the vicinity of the diaphragm. When the electric field near the throttle increases by increasing the voltage, the viscosity of the electrorheological fluid passing through the throttle in the electric field increases, the resistance to passing through the throttle increases, and therefore the outlet pressure P+ of the throttle decreases, and the bearing load capacity decreases. descend. Conversely, it is possible to increase the load capacity.

FIG. 11 shows another embodiment of the present invention, in which the bearing clearance 41
Electrodes 46 are installed so as to sandwich the two electrodes. voltage controller 4
When an electric field is applied to the bearing gap 41 by 7, the viscosity of the electrorheological fluid in the gap increases, the flow resistance increases, and therefore the pressure Pi increases and the load capacity increases. Also the 12th
As shown in the figure, if the @ pole is separated into 46 and 48 and independent electric fields are applied by independent voltage controllers, for example, while maintaining a constant load state, the electric field at 46 is increased and the electric field at 48 is increased. If the voltage is lowered, the load capacity in the area indicated by A in the figure increases, and the load capacity in the area indicated by B decreases. Therefore, the bearing can be tilted as shown in FIG. Figure 14 is a diagram showing an example in which the electric field in the aperture and the bearing gap can be controlled independently. It is possible to further increase the effect of increasing load capacity and controlling the gap.

Fig. 15 shows the configuration shown in Fig. 14 with the addition of sensors 50 and 51 that detect the floating ft (amount of bearing clearance δ) and attitude of the bearing, and this information is led to the controller 1/roller 52 to obtain the target value. Compare each voltage controller 4 based on this deviation.
．． 4.47 and 4.9 are controlled to change the electric field of each element, change the viscous resistance of the fluid, and obtain a desired bearing support. With such a structure, for example, as shown in FIG. 16, the relationship between the load and the amount of bearing clearance δ can be freely controlled as shown in ■@◎.

① is a bearing with very high rigidity, with almost no clearance change as the load changes, and it is also possible to achieve infinite rigidity within a certain load range. On the other hand, there are bearings with extremely low rigidity, and in this way, the performance of the bearing can be changed arbitrarily according to the specifications.

〔Effect of the invention〕

According to the present invention, since the viscous resistance of the flow within the bearing gap can be freely controlled, there is an effect that the load capacity, 't% increase, rigidity, etc. can be controlled to arbitrary values in real time.

Furthermore, since the viscosity of the lubricating oil can be changed according to the rotational speed of the shaft, operation with an appropriate viscosity is possible from low-speed rotation to high-speed rotation.

Furthermore, since the viscosity of the lubricating oil can be changed depending on the temperature of the lubricating oil, it is possible to avoid contact between the shaft and the bearing, seizure, etc. due to insufficient viscosity at environmental temperatures or high temperatures. In static pressure bearings, the load capacity can be lowered by changing the throttle resistance of the pressure supply section. Furthermore, with hydrostatic bearings, the above performance can be achieved more effectively by controlling both the throttle resistance and the viscous resistance of the flow within the bearing gap.

By detecting the bearing flying height and load, and controlling the throttle resistance and flow resistance within the bearing gap based on this information, bearing performance such as load capacity, rigidity, bearing posture, etc. can be freely controlled. There is.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view showing an embodiment in which the present invention is applied to a journal bearing, Fig. 2 is a transverse sectional view showing an embodiment in which the electrode structure is changed from Fig. 1, and Fig. 3 is a cross-sectional view showing an embodiment in which the present invention is applied to a journal bearing. A vertical cross-sectional view showing an embodiment applied to a bearing, Figure 4 is a cross-sectional view of a journal bearing using a tailing pad, Figure 5 is a vertical cross-sectional view of a thrust bearing, and Figure 6 is a cross-sectional view of a journal bearing using a temperature sensor. FIG. 7 is a cross-sectional view showing an example in which the viscosity is controlled by
A vertical cross-sectional view showing an example of controlling viscosity by detecting rotational progress, Figure 8 is a vertical cross-sectional view of a conventional hydrostatic bearing, Figure 9 is a view showing its pressure distribution, and Figures 10 to 7 a , 7 b
, 2 4 , 3 3 - insulator, 1 5 - pad pedestal, 15a, 15b, 15c, 15d, 19 pad, 27... temperature sensor, 35... rotation speed detector,
28.36...Controller, 4o...Aperture, 41
...bearing gap, 42...bearing, 43...electrode,
44... Voltage controller, 46... Electrode, 47...
...Voltage controller, 48... Electrode, 49... Voltage controller, 50, 51... Displacement detector, 52...
... Control 1, 5, 10, 14, 22, 30... Axis,
2, 6, 11, 23. 31...bearing, 3, 8, 12,
16,20,26,34...electrorheological fluid, 4,9,
13, 17a, 17b, 17c, 17d, 21, 29.
3 7--Power supply, 6 a, 6 b, 2 5
．． 3 2 -Electrode, Nal Day 2 Ukohaya S ■ /8 l9 /8 Ichiuke Rania 21. ．． Voltage controller cold 3 eyes 4 mouth/6゜dens viscous mud body l7 ・Voltage controller early 7 days 33 Zetsu body 37 electric i Honoka controller Hayago ■ Tower? Mother P also/0 Eye 42 @ Uke 44 Voltage controller younger brother l ■ P. No. 3 Cut 47.49 Electric F5 Controller

Claims (1)

[Claims] 1. A shaft, a bearing, and a voltage controller that can vary the voltage, and apply an electric field to electrodes provided on the shaft and the bearing to lubricate between the shaft and the bearing. A bearing device characterized by controlling the viscosity of an electrorheological fluid. 2. The bearing device according to claim 1, further comprising means for detecting states of the bearing device such as the rotational speed of the shaft and the temperature of the electrorheological fluid, and controlling the voltage of the voltage controller in accordance with changes in the state of the bearing device. 3. A shaft, a bearing divided into a plurality of segments, and a voltage controller capable of independently applying an electric field to each segment to electrodes provided on the shaft and the bearing, and performing lubrication between the shaft and the bearing. A bearing device characterized in that the viscosity of electrorheological fluid is controlled independently for each segment. 4. The bearing device according to claim 1, 2 or 3, wherein an insulator is provided on the shaft side of the bearing. 5. In a hydrostatic bearing consisting of a shaft and a bearing equipped with a fluid supply hole having a throttle for supplying fluid, electrodes are provided on each of the opposing surfaces of the shaft and the bearing, and a voltage controller capable of varying the voltage is used to A bearing device characterized in that an electric field is applied between electrodes to control the viscosity of an electrorheological fluid supplied between the shafts. 6. In a hydrostatic bearing consisting of a shaft and a bearing equipped with a fluid supply hole having a throttle for supplying fluid, the bearing has electrodes divided into a plurality of segments, and the shaft side facing the electrodes is divided into a plurality of segments. A voltage controller that can vary the voltage applies an electric field independently to each segment between the electrodes to control the viscosity of the electrorheological fluid supplied between the shaft and the bearing. A bearing device characterized by controlling heat. 7. The bearing device according to claim 6 or 7, wherein an electrode is provided on the aperture, and an electric field is applied by a voltage controller. 8. The bearing device according to claim 6, 7 or 8, wherein a bearing clearance or a load applied to the bearing is detected, and the voltage of each voltage controller is controlled based on a deviation between the detected value and a set target value.