JP2017032028A - Bearing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bearing device having sufficient properties under an environment that a temperature rises by continuous operation and the like.SOLUTION: A bearing device includes a first bearing portion 1 and a second bearing portion 2. The first bearing portion 1 has a region in which a first layer 3 composed of a first material, and a second layer 4 composed of a second material having a thermal expansion coefficient smaller than that of the first material, are stacked. The second bearing portion 2 is opposed to or fitted to the first bearing portion 1 through a clearance gap. At least one of the first bearing portion 1 and the second bearing portion 2 has rotating or sliding operation means. Further the second layer 4 is formed at a side of the second bearing portion 2, of the first bearing portion 1.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a bearing mechanism, and more particularly to a hydrostatic bearing.

  Bearings and guide mechanisms are used in the operating parts of various devices such as production facilities and transportation equipment. Rolling bearings, sliding bearings, fluid lubricated bearings, and other bearings are used as the bearings and the guide mechanism. In applications where high-speed and high-precision operation is required, hydrostatic bearings are often used. In a hydrostatic bearing, a fluid such as air or oil is used for lubrication between two relatively moving surfaces such as rotation and sliding. The hydrostatic bearing is not guided by local contact, but is guided on the fluid surface, so that high guidance accuracy can be obtained.

  Rigidity and load capacity, which are basic characteristics of the bearing, are proportional to the area of the bearing surface and inversely proportional to the air gap, which is the distance between the bearings. The area of the bearing surface is greatly limited in design in terms of the size of the device and the processing accuracy. Therefore, in order to obtain stable and high characteristics, it is necessary to design optimally the spacing between the bearings and the structure of the air supply section and exhaust section for supplying and discharging the fluid, and to appropriately use them in the usage environment. is there.

  On the other hand, during operation of the bearing device, thermal expansion of the bearing member occurs due to heat transfer from the power of the bearing, changes in the surrounding temperature, temperature rise due to fluid friction in the air gap, and the like. When the thermal expansion of the bearing member occurs, the air gap between the bearings changes, and the characteristics such as the rigidity of the bearing vary. Further, contact of the bearing surface may also occur due to expansion of the bearing member. Therefore, in order to maintain the performance in the actual use environment and operate the bearing device stably, it is necessary to maintain characteristics such as the rigidity of the bearing in the actual use environment. From such a background, development of a technique for obtaining stable characteristics in an environment where the bearing device is actually assumed to be used has been developed. As a technique for obtaining stable characteristics in an actual use environment in a bearing device, for example, a technique as disclosed in Patent Document 1 is disclosed.

  Patent Document 1 relates to a spindle device provided with a thrust bearing mechanism. In the spindle device of Patent Document 1, a thrust gap is formed between the flange portion provided in the shaft portion, the bearing body, and the bearing portion. In the bearing mechanism of Patent Document 1, members having a thermal expansion coefficient close to each other are used for the bearing body and the bearing portion near the flange portion. Patent Document 1 states that by making the thermal expansion coefficients of the bearing main body and the bearing portion close to each other, the thrust gap becomes too narrow at a low temperature and the state where the flange portion and the bearing are in contact can be avoided.

JP 2013-7393 A

  However, the technique of Patent Document 1 is not sufficient in the following points. In the bearing mechanism of Patent Document 1, when the bearing body contracts at a low temperature, the thrust gap is prevented from becoming narrow due to deformation of the bearing portion around the flange portion. For this reason, in the bearing mechanism of Patent Document 1, when the temperature rises, the bearing body and the bearing portion may thermally expand, and the thrust gap that receives the flange portion may be narrowed. When the thrust gap that receives the flange portion becomes narrow, fluctuations in characteristics such as contact and rigidity between the flange and the bearing occur. Therefore, the bearing mechanism of Patent Document 1 may not be able to obtain a stable operating state when the temperature rises due to continuous operation or the like. Therefore, the technique of Patent Document 1 is not sufficient as a technique for obtaining stable characteristics in an actual use environment in a bearing device.

  In order to solve the above-described problems, an object of the present invention is to obtain a bearing device having sufficient characteristics in an environment where the temperature has increased due to continuous operation or the like.

  In order to solve the above-described problems, the bearing device of the present invention includes a first bearing portion and a second bearing portion. The first bearing portion has a region in which a first layer formed of a first material and a second layer formed of a second material having a smaller thermal expansion coefficient than the first material are stacked. . The second bearing portion faces or fits with the first bearing portion via a gap. At least one of the first bearing portion and the second bearing portion has rotating or sliding operation means. Further, the second layer is formed on the second bearing portion side of the first bearing portion.

  According to the present invention, sufficient characteristics can be obtained in an environment where the temperature has increased due to continuous operation or the like.

It is a figure which shows the outline | summary of a structure of the 1st Embodiment of this invention. It is a perspective view which shows the structure of the bearing apparatus of the 2nd Embodiment of this invention. It is sectional drawing which shows the structure of the bearing apparatus of the 2nd Embodiment of this invention. It is a figure which shows the state of the bearing apparatus at the time of the temperature rise in the 2nd Embodiment of this invention. It is a perspective view which shows the structure of the bearing apparatus of the 3rd Embodiment of this invention. It is sectional drawing which shows the structure of the bearing apparatus of the 3rd Embodiment of this invention. It is a perspective view which shows the structure of the bearing apparatus of the 4th Embodiment of this invention. It is sectional drawing which shows the structure of the bearing apparatus of the 4th Embodiment of this invention.

(First embodiment)
A first embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing an outline of the configuration of the bearing device of the present embodiment. The bearing device of the present embodiment includes a first bearing portion 1 and a second bearing portion 2. The first bearing portion 1 includes a first layer 3 formed of a first material and a second layer 4 formed of a second material having a smaller thermal expansion coefficient than the first material. Has a region. The second bearing portion 2 faces or fits with the first bearing portion 1 via a gap. At least one of the first bearing portion 1 and the second bearing portion 2 has rotating or sliding operation means. The second layer 4 is formed on the second bearing portion 2 side of the first bearing portion 1.

  The first bearing portion 1 of the bearing device of the present embodiment has a structure in which two materials having different thermal expansion coefficients are laminated. Further, the thermal expansion coefficient of the material of the first layer 3 on the opposite side is larger than the thermal expansion coefficient of the material of the second layer 4 on the side facing the second bearing portion 2 through the gap. Therefore, when the temperature rises, the first layer 3 tends to expand more than the second layer 4, so the first bearing portion 1 is opposite to the second bearing portion 2 side. The structure is warped to increase the area of the surface. When the first bearing portion 1 is warped to increase the area of the surface opposite to the second bearing portion 2 side, the first bearing portion 1 is at the end of the first bearing portion 1. And the distance of the 2nd bearing part 2 becomes near. When the distance between the first bearing portion 1 and the second bearing portion 2 is reduced, the bearing device of this embodiment can obtain high rigidity when the temperature rises. As a result, in the bearing device of the present embodiment, sufficient characteristics can be obtained in an environment where the temperature has increased due to continuous operation or the like.

(Second Embodiment)
A second embodiment of the present invention will be described in detail with reference to the drawings. 2 and 3 show an outline of the configuration of the bearing device of the present embodiment. FIG. 2 is a perspective view of the bearing device of the present embodiment. FIG. 3 is a cross-sectional view of the bearing device of the present embodiment.

  The bearing device of this embodiment includes a lower bearing portion 11, an upper bearing body portion 12, and an upper bearing end portion 13. Further, as shown in FIG. 3, the lower bearing portion 11 includes an air supply portion 14. An air gap 15 is formed between the lower bearing portion 11 and the upper bearing main body portion 12 and the upper bearing end portion 13. An end portion of an air gap 15 formed between the lower bearing portion 11 and the upper bearing main body portion 12 and the upper bearing end portion 13 is provided as an exhaust portion 16.

  The bearing device of the present embodiment includes a thrust bearing mechanism in which a lower bearing portion 11, an upper bearing portion formed by an upper bearing main body portion 12 and an upper bearing end portion 13 are opposed or fitted in a plane via an air gap 15. Have In the bearing device according to the present embodiment, the air gap 15 is filled with a fluid such as lubricating oil, the interval between the bearing portions is maintained by the static pressure of the fluid, and the bearing portions rotate and slide.

  The lower bearing portion 11 has a function as a thrust bearing. The lower bearing portion 11 of the present embodiment is formed of SUS (Steel Use Stainless) 304 that is stainless steel. The thermal expansion coefficient of SUS304 used in this embodiment is 17.3 ppm. The lower bearing portion 11 may be formed of stainless steel other than SUS304 or other metals. An air supply portion 14 is formed in the lower bearing portion 11. The lower bearing portion 11 of the present embodiment corresponds to the second bearing portion 2 of the first embodiment.

  The upper bearing main body 12 has a function as a thrust bearing by being combined with the upper bearing end 13. The lower bearing portion 11, the upper bearing main body portion 12, and the upper bearing end portion 13 are opposed to or fitted to each other in a plane via the air gap 15. The upper bearing body 12 of the present embodiment is formed of the same material as the lower bearing 11, that is, SUS304 that is stainless steel. Therefore, the thermal expansion coefficient of the upper bearing body 12 of this embodiment is 17.3 ppm. The upper bearing body 12 may be formed of stainless steel other than SUS304 or other metals. Further, the lower bearing portion 11 and the upper bearing body portion 12 may be formed of different stainless steels or other metals.

  The upper bearing end 13 has a function as a thrust bearing in combination with the upper bearing main body 12. Further, the upper bearing end 13 has a function as a member for adjusting the interval of the air gap 15. The upper bearing end portion 13 is formed on the lower bearing portion 11 side near the exhaust portion 16 of the upper bearing body portion 12. In the vicinity of the exhaust portion 16, the upper bearing main body portion 12 and the upper bearing end portion 13 made of different metals are laminated. That is, in the vicinity of the exhaust part 16, the thrust bearing formed by the upper bearing main body part 12 and the upper bearing end part 13 has a bimetallic structure.

  The upper bearing end 13 is formed using a metal having a smaller coefficient of thermal expansion than the upper bearing body 12. The thermal expansion coefficient of the material used for the upper bearing end 13 is preferably less than half the thermal expansion coefficient of the material used for the upper bearing body 12. In the present embodiment, the upper bearing end 13 is made of titanium. The thermal expansion coefficient of titanium used for the upper bearing end 13 of this embodiment is 8.0 ppm. The upper bearing end 13 may be made of a metal other than titanium.

  Further, the upper bearing end 13 of the present embodiment is joined to the upper bearing main body 12 and formed as an integral member. For example, the upper bearing end 13 is joined to the upper bearing body 12 by welding or adhesion. By joining the upper bearing body 12 and the upper bearing end 13, the deformation effect due to the difference in thermal expansion coefficient is improved.

  The upper bearing body 12 and the upper bearing end 13 may be formed as separable members. By forming the bearing in a state where the upper bearing main body 12 and the upper bearing end 13 can be separated, only one of the corresponding members can be exchanged when one of them is damaged. When the upper bearing body 12 and the upper bearing end 13 are separable, the upper bearing end 13 is fixed to the upper bearing body 12 at two or more locations including the vicinity of the center and the periphery. It is desirable to fix with tools. This is because by fixing with two or more, the degree of freedom is suppressed when the upper bearing body 12 is thermally expanded, and the effect of causing warpage is enhanced.

  In the present embodiment, SUS304 having a large thermal expansion coefficient and high hardness is used for the upper bearing body 12. Further, titanium having a low thermal expansion coefficient and low hardness is used for the upper bearing end portion 13. Therefore, when an abnormality occurs such that the supply of fluid suddenly stops, there is a high possibility that the upper bearing end portion 13 contacts the lower bearing portion 11 and is damaged. In such a case, it may be possible to use it again as a bearing by simply replacing the upper bearing end 13. Since the hydrostatic bearing is required to have high surface accuracy, maintainability is improved by adopting a configuration in which each member can be replaced.

  The bearing formed by the upper bearing body 12 and the upper bearing end 13 of the present embodiment corresponds to the first bearing 1 of the first embodiment. Further, the upper bearing body 12 corresponds to the first layer 3 of the first bearing 1 of the first embodiment. The upper bearing end portion 13 corresponds to the second layer 4 of the first bearing portion 1 of the first embodiment.

  The air supply unit 14 has a function as a path for supplying a pressurized fluid to the air gap 15. In the bearing device of the present embodiment, the air supply unit 14 is provided in the lower bearing unit 11. The air supply unit 14 is connected to a fluid supply pipe. The pressurized fluid shared via the air supply unit 14 is filled in the air gap 15 and discharged from the exhaust unit 16. A plurality of air supply units 14 may be provided. As the fluid, pressurized gas, lubricating oil or the like is used.

  The air gap 15 is a space formed between the lower bearing portion 11, the upper bearing main body portion 12 and the upper bearing end portion 13. During operation, the air gap 15 is filled with a fluid pressurized through the air supply unit 14. The air gap 15 is formed such that the interval between the lower bearing portion 11, the upper bearing main body portion 12 and the upper bearing end portion 13 is on the order of micrometers. Further, in the present embodiment, due to the temperature rise during operation, the distance between the lower bearing portion 11 and the upper bearing end portion 13 near the exhaust portion 16 is set so that the lower bearing portion 11 and the upper bearing body portion near the center of the bearing device. It becomes narrower than the interval of 12.

  The space | interval of the air gap 15 is set according to the rigidity characteristic requested | required of a bearing apparatus. The space | interval of the air gap 15 means the distance of the plane of the lower bearing part 11, and the plane which the upper bearing main-body part 12 and the upper bearing end part 13 form. The distance between the air gaps 15 in the present embodiment takes into account the amount of deformation of the lower bearing portion 11, the upper bearing main body portion 12 and the upper bearing end portion 13 at a temperature assumed in an environment where the bearing device is actually used. Is set. That is, the distance of the air gap 15 is set in consideration of the distance from the opposite lower bearing portion 11 when the member warps due to thermal expansion of the upper bearing main body portion 12 and the upper bearing end portion 13.

  In the bearing device of this embodiment, the thermal expansion coefficient of the material of the upper bearing body 12 is larger than the thermal expansion coefficient of the material of the upper bearing end 13. Therefore, when the temperature rises during operation of the bearing device, the upper bearing body 12 tends to expand more than the upper bearing end 13. However, since the upper bearing body 12 and the upper bearing end 13 are formed as an integral member, the upper bearing body 12 is affected by the upper bearing end 13 when expanded. At that time, since the upper bearing body 12 expands more greatly, the upper bearing body 12 and the upper bearing end 13 are deformed and warped so that the surface opposite to the air gap 15 is in a convex state. It becomes. That is, as the temperature rises, the gap between the lower bearing portion 11 and the upper bearing end portion 13 near the periphery of the air gap 15 becomes narrower than the gap between the lower bearing portion 11 and the upper bearing body portion 12 near the center. It becomes.

  Since the gap between the air gap 15 and the vicinity of the air gap 15, that is, near the exhaust portion 16 becomes narrow, the bearing device of this embodiment has the same structure as the exhaust throttle when the temperature rises. That is, in the bearing device according to the present embodiment, the rigidity of the bearing characteristics can be increased by using the temperature rise by using a bimetallic structure in which two substances having different thermal expansion coefficients are connected around the exhaust portion 16.

  Further, the bearing device of the present embodiment includes the upper bearing end portion 13 having a different thermal expansion coefficient only in the vicinity of the periphery, that is, in the vicinity of the exhaust portion 16. The portion other than the exhaust portion 16 is provided with a single layer of the upper bearing portion 12 made of the same material as that of the lower bearing portion 11 on the opposite side, thereby estimating an interval variation due to the temperature of the air gap 15 and Control becomes easy. As a result, since the average interval of the air gap 15 can be controlled with high accuracy, the rigidity of the bearing device is stabilized. Further, in the vicinity of the exhaust portion 16, since the rigidity of the air gap 15 is narrowed to increase the rigidity, by providing the upper bearing end portion 13 in the vicinity of the exhaust portion 16, the overall rigidity of the bearing device can be controlled. It is possible to achieve both improvement in rigidity.

  The exhaust unit 16 has a function of discharging the fluid filled in the air gap 15. The exhaust part 16 is formed at the end of an air gap 15 formed between the lower bearing part 11 and the upper bearing body part 12 and the upper bearing end part 13.

  2 and 3, the upper bearing body 12 and the upper bearing end 13 are shown on the upper side and the lower bearing part 11 is shown on the lower side, but the upper and lower parts may be installed upside down. That is, the lower bearing portion 11 may be installed on the upper side, and the upper bearing main body portion 12 and the upper bearing end portion 13 may be installed on the lower side. Moreover, you may install in the horizontal direction instead of the up-down direction. Further, the intake portion 14 may be provided in the upper bearing body portion 12.

  The operation of the bearing device of this embodiment will be described. In the bearing device of the present embodiment, a predetermined fluid is pressurized and supplied from the air supply unit 14 during operation. In this embodiment, lubricating oil is used as the predetermined fluid. The predetermined fluid may be a pressurized gas or a liquid other than the lubricating oil. Lubricating oil supplied from the air supply unit 14 is filled in the air gap 15. The lubricating oil filled in the air gap 15 is sequentially discharged from the exhaust unit 16.

  When the air gap 15 is filled with lubricating oil, the load acting on the bearing is supported by the static pressure of the lubricating fluid film. The lower bearing portion 11, the upper bearing main body portion 12, and the upper bearing end portion 13 maintain an interval by the static pressure of the fluid and perform operations such as rotation or sliding. Operations such as rotation or sliding are performed by movement of at least one of the lower bearing portion 11 and the upper bearing portion formed by the upper bearing main body portion 12 and the upper bearing end portion 13.

  During continuous operation, the temperature of each part of the bearing device rises due to heat transfer from power, temperature rise in the device, temperature rise due to fluid friction, and the like. When the temperature rises, each part of the bearing device thermally expands. FIG. 4 schematically shows the state of the bearing device of this embodiment when the temperature rises.

  When the upper bearing main body portion 12 and the upper bearing end portion 13 are thermally expanded, the upper bearing main body portion 12 has a larger thermal expansion coefficient than the upper bearing end portion 13 and therefore tends to expand larger. Since the upper bearing main body portion 12 and the upper bearing end portion 13 are joined to each other, the joint surface side of the upper bearing main body portion 12 with the upper bearing end portion 13 cannot expand freely. On the other hand, the surface of the upper bearing main body 12 opposite to the upper bearing end 13 can freely expand. Therefore, the upper bearing body 12 is warped by thermal expansion. When the upper bearing body 12 is warped by thermal expansion, a structure is formed such that the surface opposite to the air gap 15 has a peak and the surface on the air gap 15 side becomes a valley. In such a structure, the upper bearing main body portion 12 tends to increase its area freely by thermal expansion on the surface opposite to the air gap 15, while the upper bearing end portion 13 and the upper bearing end portion 13 on the surface facing the air gap 15. It is formed by being restrained by the joint surface.

  When the upper bearing main body portion 12 is warped, the upper bearing end portion 13 joined to the upper bearing main body portion 12 approaches the lower bearing portion 11 in the vicinity of the air gap 15, that is, in the vicinity of the exhaust portion 16. It becomes a state. When the upper bearing end portion 13 and the lower bearing portion 11 are close to each other, the rigidity of the bearing device is increased. Therefore, the bearing device of this embodiment operates in a highly rigid state as the temperature rises.

  Further, in the bearing device of this embodiment, even when the gap of the air gap 15 is widened near the center due to the upper bearing main body 12 being warped by thermal expansion, the gap is narrow near the periphery, so that the entire device as a whole. Can suppress the fluctuation of rigidity.

  The bearing device of this embodiment is provided with a bearing portion having a bimetallic structure using metals having different coefficients of thermal expansion at the upper bearing main body portion 12 and the upper bearing end portion 13. The bearing device according to the present embodiment uses a metal having a small thermal expansion coefficient for the upper bearing end 13 on the air gap 15 side and a metal having a large thermal expansion coefficient for the upper bearing main body 12 on the side opposite to the air gap 15. It has a structure. Therefore, in the bearing device of the present embodiment, the air gap 15 tends to expand more on the side opposite to the air gap, so that the air gap 15 is narrowed only at the periphery when the temperature rises. In the bearing device of the present embodiment, the air gap 15 in the peripheral portion becomes narrow when the temperature rises, so that the rigidity is increased. Moreover, since the bearing apparatus of this embodiment is improving rigidity using the deformation | transformation by the thermal expansion of a bearing part, in order to improve rigidity, another special mechanism is not required. Therefore, in the bearing device of this embodiment, the rigidity of the bearing can be increased while suppressing the complexity of the device configuration and the increase in size of the device. As described above, in the bearing device of the present embodiment, high rigidity can be obtained in an actual use environment in which the temperature rises more than normal temperature without causing a complicated device configuration or an increase in the size of the device. As a result, in the bearing device of the present embodiment, sufficient characteristics can be obtained in an environment where the temperature has increased due to continuous operation or the like.

(Third embodiment)
A third embodiment of the present invention will be described in detail with reference to the drawings. 5 and 6 show the outline of the configuration of the bearing device of the present embodiment. FIG. 5 is a perspective view of the bearing device of the present embodiment. FIG. 6 is a cross-sectional view of the bearing device of the present embodiment. In the second embodiment, the bearing device corresponding to the thrust bearing mechanism has been described. However, the bearing device of the present embodiment is characterized in that it corresponds to the air slide guide mechanism.

  The bearing device of the present embodiment includes a guide portion 21, a stage main body portion 22, and a stage end portion 23. Further, as shown in FIG. 6, the guide part 21 includes an air supply part 24. An air gap 25 is formed between the guide portion 21 and the stage main body portion 22 and the stage end portion 23. The functions of the air supply unit 24, the air gap 25, and the exhaust unit 26 are the same as those of the parts having the same names in the second embodiment.

  The bearing device of this embodiment has an air slide guide mechanism including a guide portion 21 through an air gap 25 inside a stage formed by the stage main body portion 22 and the stage end portion 23. In the bearing device of this embodiment, the air gap 25 is filled with a fluid such as lubricating oil, and the distance between the guide portion 21, the stage main body portion 22, and the stage end portion 23 is maintained by the static pressure of the fluid. In the bearing device of the present embodiment, the stage body 22 and the stage end 23 operate along the long axis direction of the guide 21.

  The guide part 21 has a function as a guide when the stage formed by the stage main body part 22 and the stage end part 23 operates. The guide part 21 of this embodiment is formed of SUS304 that is stainless steel. The thermal expansion coefficient of SUS304 used in this embodiment is 17.3 ppm. The guide part 21 may be formed of stainless steel or other metals other than SUS304. In addition, an air supply part 24 is formed in the guide part 21.

  The stage main body portion 22 has a function of operating along the long axis direction of the guide portion 21. The stage main body portion 22 of the present embodiment is formed of the same material as the guide portion 21, that is, SUS304. Therefore, the thermal expansion coefficient of the stage main body portion 22 of this embodiment is 17.3 ppm. The stage main body 22 may be formed of stainless steel or other metal other than SUS304. Moreover, the guide part 21 and the stage main-body part 22 may be formed with a mutually different metal.

  The stage end portion 23 has a function of moving along the major axis direction of the guide portion 21 together with the stage main body portion 22 and a function of adjusting the width of the air gap 25 in the vicinity of the exhaust portion 26. The stage end 23 is formed in the vicinity of the exhaust part 26. In the vicinity of the exhaust part 26, a stage main body part 22 and a stage end part 23 made of different metals are laminated and formed. That is, in the vicinity of the exhaust portion 26, a bimetal structure is formed by the stage main body portion 22 and the stage end portion 23. The stage end 23 is joined to the stage main body 22, and the stage main body 22 and the stage end 23 are formed as an integral member. The stage end 23 is joined to the stage main body 22 by welding or adhesion, for example.

  The stage main body 22 and the stage end 23 may be formed as separate removable members. When the stage main body portion 22 and the stage end portion 23 are configured to be separable, the stage end portion 23 may be fixed to the stage main body portion 22 with a fixture at two or more locations in the stage long axis direction. desirable. This is because, by fixing with two or more, the degree of freedom is suppressed when the stage main body portion 22 is thermally expanded, and the effect of causing warpage is enhanced.

  The stage end 23 is formed using a metal having a smaller thermal expansion coefficient than the stage main body 22. The thermal expansion coefficient of the material used for the stage end 23 is preferably less than half the thermal expansion coefficient of the material used for the stage main body 22. In the present embodiment, the stage end 23 is made of titanium. The thermal expansion coefficient of titanium used in the stage end portion 23 of this embodiment is 8.0 ppm. The stage end portion 23 may be formed of a metal other than titanium.

  The operation of the bearing device of this embodiment will be described. In the bearing device of the present embodiment, a predetermined fluid is pressurized and supplied from the air supply unit 24 during operation as in the second embodiment. In this embodiment, lubricating oil is used as the predetermined fluid. Lubricating oil supplied from the air supply unit 24 is filled in the air gap 25. Further, the lubricating oil filled in the air gap 25 is sequentially discharged from the exhaust part 26.

  When the air gap 25 is filled with lubricating oil, the gap between the guide portion 21, the stage main body portion 22, and the stage end portion 23 is maintained by the static pressure of the lubricating fluid film. The stage formed by the guide part 21, the stage main body part 22 and the stage end part 23 maintains a gap by the static pressure of the fluid. The stage formed by the stage main body portion 22 and the stage end portion 23 operates along the long axis direction of the guide portion 21.

  During continuous operation, the temperature of each part of the bearing device rises due to heat transfer from the power, temperature rise in the device, temperature rise due to fluid friction, and the like. When the temperature rises, each part of the bearing device thermally expands. When the stage main body portion 22 and the stage end portion 23 are thermally expanded, the stage main body portion 22 has a larger thermal expansion coefficient than the stage end portion 23 and therefore tends to expand larger. Since the stage body 22 and the stage end 23 are joined together, the stage body 22 is warped by thermal expansion.

  When the stage main body portion 22 is warped, the stage end portion 23 joined to the stage main body portion 22 is close to the guide portion 21 near the end of the stage, that is, near the exhaust portion 26. For this reason, the bearing device of this embodiment has high rigidity in the vicinity of the exhaust port 26 at the end of the stage when the temperature rises during actual use or the like. As a result, the bearing device of the present embodiment has high rigidity under the actual use environment.

  Further, when the temperature rises, the vicinity of the center of the stage also approaches the vicinity of the periphery even when the guide portion 21 and the stage main body 22 are slightly separated from each other. The amount is suppressed.

  In the present embodiment, the stage formed by the stage main body 22 and the stage end 23 is operated as a movable part, but the guide 21 may be moved. The intake section 24 may be provided in the stage main body section 22. In this embodiment, the stage formed by the stage main body 22 and the stage end 23 is a movable part, but the movable part may be other than the stage.

  The bearing device of this embodiment includes a bimetallic structure bearing portion using metals having different coefficients of thermal expansion at the stage main body portion 22 and the stage end portion 23. In the bearing device of the present embodiment, a metal having a small thermal expansion coefficient is used for the stage end portion 23 on the side facing the guide portion 21, and a metal having a large thermal expansion coefficient is used for the stage main body portion 22 on the side opposite to the guide portion 21. It has a bimetal structure. Therefore, in the bearing device of the present embodiment, the air gap 25 is narrowed only around the exhaust port 26 at the end of the stage when the temperature rises because the bearing device tends to expand more greatly on the side opposite to the guide portion 21. . In the bearing device of the present embodiment, the air gap 25 becomes narrow at the end of the stage when the temperature rises, so that the rigidity is increased. Moreover, since the bearing apparatus of this embodiment is improving rigidity using the deformation | transformation by the thermal expansion of the stage main-body part 22, in order to improve rigidity, another special mechanism is not required. As described above, in the bearing device of the present embodiment, high rigidity can be obtained in an actual use environment in which the temperature rises more than normal temperature without causing a complicated device configuration or an increase in the size of the device. As a result, in the bearing device of the present embodiment, sufficient characteristics can be obtained in an environment where the temperature has increased due to continuous operation or the like.

(Fourth embodiment)
A fourth embodiment of the present invention will be described in detail with reference to the drawings. 7 and 8 show an outline of the configuration of the bearing device of the present embodiment. The bearing device of the present embodiment has a spindle mechanism.

  The bearing device of this embodiment includes a main shaft portion 31, a rotating body main body portion 32, and a rotating body end portion 33. Further, as shown in FIG. 8, the main shaft portion 31 includes an air supply portion 34. In addition, an air gap 35 is formed between the main shaft portion 31, the rotating body main body portion 32, and the rotating body end portion 33. The functions of the air supply unit 34, the air gap 35, and the exhaust unit 36 are the same as those of the parts having the same names in the second embodiment.

  The bearing device of the present embodiment has a spindle mechanism including a main shaft portion 31 through an air gap 25 inside a rotating body formed by the rotating body main body 32 and the rotating body end 33. In the bearing device of the present embodiment, the air gap 35 is filled with a fluid such as lubricating oil, and the distance between the main shaft portion 31, the rotating body main body portion 32, and the rotating body end portion 33 is maintained by the static pressure of the fluid. In the bearing device of the present embodiment, the rotating body formed by the rotating body main body 32 and the rotating body end 33 performs a rotating operation in the circumferential direction with the main shaft portion 31 as the rotation center.

  The main shaft portion 31 has a function as a rotating shaft of a rotating body formed by the rotating body main body portion 32 and the rotating body end portion 33. The main shaft portion 31 of the present embodiment is formed of SUS304 that is stainless steel. The thermal expansion coefficient of SUS304 used in this embodiment is 17.3 ppm. The main shaft portion 31 may be formed of stainless steel other than SUS304 or other metals. In addition, an air supply portion 34 is formed in the main shaft portion 31.

  The rotator main body 32 has a function as a rotator that performs a rotation operation with the main shaft 31 as a rotation axis. The rotating body main body 32 of the present embodiment is formed of the same material as the main shaft portion 31, that is, SUS304. Therefore, the thermal expansion coefficient of the rotating body main body 32 of the present embodiment is 17.3 ppm. The rotating body main body 32 may be formed of stainless steel other than SUS304 or other metals. Further, the main shaft portion 31 and the rotating body main body portion 32 may be formed of different metals.

  The rotating body end portion 33 has a function of performing a rotating operation together with the rotating body main body portion 32 and a function of adjusting an interval of the air gap 35 in the vicinity of the exhaust portion 36. The rotating body end 33 is formed in the vicinity of the exhaust part 36. In the vicinity of the exhaust part 36, the rotary body main body 32 and the rotary body end 33 made of different metals are laminated. That is, a bimetal structure is formed in the vicinity of the exhaust part 36 by the rotating body main body 32 and the rotating body end 33. In the present embodiment, the rotating body end portion 33 is joined to the rotating body main body portion 32, and the rotating body main body portion 32 and the rotating body end portion 33 are formed as an integral member. The rotating body end 33 is joined to the rotating body main body 32 by welding or adhesion, for example.

  The rotator main body 32 and the rotator end 33 may be formed as separate removable members. When the rotary body main body 32 and the rotary body end 33 are separable, the rotary body end 33 is fixed to the rotary body main body 32 at two or more locations in the longitudinal direction of the rotary body. It is desirable to be fixed with. This is because, by fixing with two or more, the degree of freedom is suppressed when the rotating body main body 32 is thermally expanded, and the effect of causing warpage is enhanced.

  The rotating body end portion 33 is formed using a metal having a smaller thermal expansion coefficient than the rotating body main body portion 32. The thermal expansion coefficient of the material used for the rotating body end 33 is preferably less than half the thermal expansion coefficient of the material used for the rotating body main body 32. In the present embodiment, the rotating body end portion 33 is made of titanium. The thermal expansion coefficient of titanium used in the rotating body end portion 33 of this embodiment is 8.0 ppm. The rotating body end portion 33 may be formed of a metal other than titanium.

  The operation of the bearing device of this embodiment will be described. In the bearing device of the present embodiment, a predetermined fluid is pressurized and supplied from the air supply unit 34 during operation as in the second embodiment. In this embodiment, lubricating oil is used as the predetermined fluid. Lubricating oil supplied from the air supply unit 34 is filled in the air gap 35. Further, the lubricating oil filled in the air gap 25 is sequentially discharged from the exhaust part 36.

  When the air gap 35 is filled with lubricating oil, the space between the main shaft portion 31, the rotating body main body portion 32, and the rotating body end portion 33 is maintained by the static pressure of the lubricating fluid film. The main shaft portion 31, the rotator main body portion 32, and the rotator end portion 33 maintain the air gap 35 by the static pressure of the fluid. The rotator formed by the rotator main body 32 and the rotator end 33 performs a rotation operation with the major axis of the main shaft 31 as the center of rotation.

  During continuous operation, the temperature of each part of the bearing device rises due to heat transfer from the power, temperature rise in the device, temperature rise due to fluid friction, and the like. When the temperature rises, each part of the bearing device thermally expands. When the rotator main body 32 and the rotator end 33 thermally expand, the rotator main body 32 tends to expand more because the coefficient of thermal expansion is larger than that of the rotator end 33. Since the rotator main body 32 and the rotator end 33 are joined to each other, the rotator main body 32 is warped by thermal expansion.

  When the rotator main body 32 is warped, the rotator end 33 joined to the rotator main body 32 approaches the main shaft 31 near the end of the rotator, that is, near the exhaust portion 36. . Therefore, the rigidity is increased at the end of the rotating body. As a result, the bearing device of the present embodiment has high rigidity under an actual use environment in which the temperature rises above the normal temperature.

  Further, even when the main shaft portion 31 and the rotating body main body portion 32 are slightly separated from each other near the center of the rotating body due to warpage when the temperature rises, the peripheral portion approaches the bearing portion. In the entire apparatus, the amount of change in rigidity is suppressed.

  In the present embodiment, the rotating body side formed by the rotating body main body portion 32 and the rotating body end portion 33 operates as a movable portion. However, the main shaft portion 31 side may be configured to move. The intake portion 34 may be provided in the rotating body main body 32.

  The bearing device of the present embodiment includes a bimetallic structure bearing portion using metals having different thermal expansion coefficients at the rotating body main body 32 and the rotating body end 33. In the bearing device of the present embodiment, a metal having a small thermal expansion coefficient is used for the rotating body end portion 33 on the side facing the main shaft portion 31, and a metal having a large thermal expansion coefficient is used for the rotating body main body portion 32 on the side opposite to the main shaft portion 31. It has the bimetal structure used. Therefore, in the bearing device of the present embodiment, the air gap 35 is narrowed only in the peripheral portion when the temperature rises because the bearing device tends to expand more greatly on the side opposite to the main shaft portion 31. In the bearing device of this embodiment, the air gap 35 in the peripheral portion is narrowed when the temperature rises, so that the rigidity is increased. Moreover, since the bearing apparatus of this embodiment has improved rigidity using the deformation | transformation by the thermal expansion of the rotary body main-body part 32, in order to improve rigidity, another special mechanism is not required. As described above, in the bearing device of the present embodiment, high rigidity can be obtained in an actual use environment in which the temperature rises more than normal temperature without causing a complicated device configuration or an increase in the size of the device. As a result, in the bearing device of the present embodiment, sufficient characteristics can be obtained in an environment where the temperature has increased due to continuous operation or the like.

  In the second to fourth embodiments, the member of the bearing portion is formed of metal, but the member of the bearing portion may be formed of a combination of resin or ceramic having a difference in thermal expansion. Moreover, the surface of the metal of each site | part may be processed with the other metal, resin, etc.

DESCRIPTION OF SYMBOLS 1 1st bearing part 2 2nd bearing part 3 1st layer 4 2nd layer 11 Lower bearing part 12 Upper bearing main-body part 13 Upper bearing end part 14 Air supply part 15 Air gap 16 Exhaust part 21 Guide part 22 Stage Main Body 23 Stage End 24 Air Supply Part 25 Air Gap 26 Exhaust Part 31 Main Shaft Part 32 Rotating Body Main Part 33 Rotating Body End Part 34 Air Supply Part 35 Air Gap 36 Exhaust Part

Claims (10)

1st bearing part which has the area | region which laminated | stacked the 1st layer formed with the 1st material, and the 2nd layer formed with the 2nd material whose thermal expansion coefficient is smaller than the said 1st material When,
A second bearing portion facing or fitting with the first bearing portion through a gap;
At least one of the first bearing portion and the second bearing portion has a rotating or sliding operation means,
The bearing device, wherein the second layer is formed on the second bearing portion side of the first bearing portion.   The gap formed between the first bearing portion and the second bearing portion is narrower in the vicinity of the periphery than in the vicinity of the center due to deformation of the first bearing portion when the temperature rises. The bearing device according to claim 1.   The first bearing portion is formed of the first layer in the substantially entire surface opposite to the second bearing portion side and in the vicinity of the center of the second bearing portion side, and the second bearing portion side. 3. The bearing device according to claim 1, wherein the vicinity of the bearing is formed of the second layer. An air supply part that is formed in the first bearing part or the second bearing part and injects a fluid;
An exhaust part that is formed near the periphery of the gap between the first bearing part and the second bearing part and that discharges the fluid;
4. The bearing device according to claim 1, wherein the air supply unit and the exhaust unit are connected to the gap, and the fluid is filled in the gap. 5.   The first layer and the second layer of the first bearing portion are joined to each other, and the first bearing portion is formed as an integral member. A bearing device according to claim 1.   5. The bearing device according to claim 1, wherein the first bearing portion is formed as a member in which the first layer and the second layer can be separated from each other.   The bearing device according to claim 1, wherein the first bearing portion and the second bearing portion face each other with the gap therebetween. The second bearing portion is provided inside the first bearing portion such that the major axis direction of the second bearing portion is substantially parallel to the major axis direction of the first bearing portion,
The bearing device according to claim 1, wherein the gap is provided between an outer peripheral portion of the second bearing portion and an inner peripheral portion of the first bearing portion.   The bearing device according to claim 8, wherein at least one of the first bearing portion and the second bearing portion operates in the long axis direction.   The bearing device according to claim 8, wherein at least one of the first bearing portion and the second bearing portion operates with the long axis as a rotation center.

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