JP4629256B2 - Variable throttle hydrostatic bearing - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a variable throttle hydrostatic bearing, and more particularly to a variable throttle hydrostatic bearing having a plurality of throttles.
[0002]
[Prior art and problems to be solved by the invention]
Conventionally, various techniques have been proposed as variable throttle hydrostatic bearings. For example, Japanese Patent No. 1888555 proposes a technique in which a second stage of the two stages of diaphragms is formed on a movable object, and the outline thereof is as follows. As shown in FIG. 14, the bearing in which the second stage of the two stage throttles is formed on a movable object includes a fluid supply port 80, a first stage fixed throttle 82, a second stage fixed throttle 84, and a fluid discharge port. 86. The fluid entered from the fluid supply port 80 passes through the first-stage fixed throttle 82 and flows into the lower pocket portion 88. Thereafter, the fluid is divided into two directions, and one of the fluids passes through the second-stage fixed throttle 84 and enters the upper pocket 90, and then passes through the gap 96 between the load shaft 92 and the upper surface of the bearing body 94 to the outside. To be discharged. The other fluid passes through the lower part of the second stage fixed throttle 84 and is discharged from the fluid discharge port 86. By adopting such a bearing structure, the following pressure compensation action can be obtained.
[0003]
Now, when the load of the load shaft 92 increases from a certain balanced state, the load shaft 92 is displaced downward in FIG. Then, the gap 96 on the lower side of the load shaft 92 is narrowed, and the flow rate of the fluid passing through the gap 96 is reduced, so that the pressure in the upper pocket portion 90 located on the lower side of the load shaft 92 increases. This increase in pressure pushes the movable object downward. Conversely, the pressure in the upper pocket portion 90 located on the upper side of the load shaft 92 decreases. As described above, the pressure in the upper pocket 90 increases, and the movable object is displaced downward by the balance of the fluid force applied to the movable object. As a result, the gap between the lower portion of the second stage fixed throttle 84 and the inlet of the fluid discharge port 86 is narrowed, and the discharge flow rate is reduced. As a result, the pressure in the lower pocket 88 of the first stage fixed throttle 82 is increased, and the fluid from the lower pocket 88 flows through the second stage fixed throttle 84 made of a movable object and flows into the upper pocket portion 90 to increase the pressure. Thus, the displacement of the load shaft 92 is prevented.
[0004]
However, in the aperture bearing using the movable object as described above, since the second stage aperture is formed on the movable object, when the load from the load shaft changes or the movable object moves, the movable object Will contact or collide with the bearing body. For this reason, there has been a problem that the movable object or the bearing body is damaged or worn by friction or impact due to contact or collision, or that the smooth operation of the movable object is hindered.
[0005]
The present invention has been made to solve the above-mentioned problems, and suppresses damage and wear of the movable object and the inner wall of the bearing body due to collision and contact between the movable object formed with the throttle and the inner wall of the bearing body. Another object of the present invention is to provide a variable throttle hydrostatic bearing capable of ensuring a smooth operation of a movable object.
[0006]
[Means for Solving the Problems]
In order to solve the above problems, a variable throttle hydrostatic bearing according to the present invention includes a fluid supply port for supplying a fluid, a first flow rate of a fluid supplied from the fluid supply port, and the flow rate of the fluid supplied to the inside. A fixed throttle and a fluid discharge port for discharging the fluid that has flowed in, a bearing body disposed at a distance from the load shaft, and movably accommodated within the bearing body, and the bearing body The interior is partitioned into a first chamber on the load shaft side and a second chamber communicated with the first fixed throttle and the fluid discharge port, and the first chamber and the second chamber communicate with each other. A second fixed throttle for reducing the flow rate of at least one of the fluid flowing into the second chamber from the first chamber and the fluid flowing into the first chamber from the second chamber, and one end opened to the second chamber And the other end opens to a contact portion with the inner wall of the bearing body, and Third fixed stop that form a fluid film between the inner wall of the bearing body for the aperture of the flow rate of fluid to the inner wall direction of the bearing main body is configured to include a movable object formed.
[0007]
According to the present invention, when the load shaft is displaced, the fluid pressure in the first chamber increases and the movable object is displaced toward the first fixed throttle. Due to this displacement, the fluid pressure in the second chamber rises, and the fluid flowing in from the first fixed throttle flows into the first chamber through the second fixed throttle and increases the pressure to prevent displacement of the load shaft. At the same time, the fluid flowing in from the first fixed throttle flows through the third fixed throttle formed in the movable object and flows out into the gap formed between the inner wall of the bearing body and the opposed part of the movable object. Since a fluid film is formed on the inner surface of the movable body and the inner wall of the bearing body due to collision and friction between the movable body and the bearing body when the movable object is displaced due to fluctuations in the load axis, etc. Smooth operation can be ensured.
[0008]
In the present invention, at least one of the first fixed throttle and the second fixed throttle can be a throttle by a porous formed in a porous object.
[0009]
In the present invention, at least one of the first fixed throttle and the second fixed throttle may be a throttle formed by a capillary hole.
[0010]
In the present invention, the first fixed throttle may be a throttle by a capillary hole, and the second fixed throttle may be a throttle by a porous formed in a porous object.
[0011]
Furthermore, the first fixed throttle may be a throttle by a porous formed in a porous object, and the second fixed throttle may be a throttle by a capillary hole.
[0012]
In the present invention, the first fixed throttle can also be a throttle by the orifice effect.
[0013]
In the present invention, the variable throttle hydrostatic thrust bearing can be configured by using the variable throttle hydrostatic bearing according to any one of claims 1 to 6 as a thrust bearing.
[0014]
In the present invention, a variable throttle hydrostatic journal bearing can be configured as a journal bearing by using a plurality of variable throttle hydrostatic thrust bearings according to claim 7.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the variable throttle hydrostatic bearing of the present invention will be described below with reference to the drawings.
[First Embodiment]
As shown in FIGS. 1 and 2, the variable throttle hydrostatic bearing 12 of the present embodiment constitutes a thrust bearing, and comprises a bearing body upper part 10 </ b> A, a bearing body lower part 10 </ b> B, and a movable object 14.
[0016]
As shown in FIGS. 1 and 3, the bearing body upper portion 10 </ b> A of the variable throttle hydrostatic bearing 12 includes a throttle movable portion 22 that penetrates the center portion, an upper pocket 20 on the load shaft 16 side, and an opposite to the upper pocket 20. A lower pocket 24 is formed on the side. The load shaft 16 and the variable throttle hydrostatic bearing 12 are disposed with a gap 18 therebetween, and the upper pocket 20 side is in contact with the load shaft 16 through the gap 18. A passage 46 is formed in the bearing body upper portion 10A so as to communicate the upper pocket 20 and the side surface of the bearing body upper portion 10A. A pressure gauge 26 is installed at a side surface outlet of the bearing body upper portion 10A of the passage 46.
[0017]
The movable object 14 is fitted to the diaphragm movable unit 22 via the gap 32 and moves up and down in the diaphragm movable unit 22. An upper pocket 34 is formed on the load shaft 16 side of the movable object 14, and a first chamber is formed by the upper pocket 34, the upper pocket 20, and the movable portion 22. A cylindrical magnet 30 joined to the plate 28 is attached to the outer periphery of the yoke portion 14 </ b> A of the movable object 14. Side pockets 36 are formed at four equally spaced positions on the outer peripheral side surface of the movable object 14. A third fixed throttle 38 is perforated so as to communicate with each side pocket 36 from one central portion of the movable object 14 on the bearing body lower part 10B side. The movable object 14 is perforated at two locations with a second fixed aperture 40 communicating with the upper and lower surfaces of the movable object 14.
[0018]
The bearing body lower part 10B is formed with a convex part 54 at the center part on the side in contact with the bearing main body upper part 10A, and an annular pocket 56 is formed outside the convex part 54. A voice coil 58 is installed. The cylindrical magnet 30 is inserted between the convex portion 54 and the voice coil 58, and the movable object 14 is in a floating state via the gap 22 above the convex portion 54. The voice coil 58 is connected to a control device 60, and the control device 60 is connected to a position sensor 62 for detecting the position of the load shaft 16. A lower pocket 48 is formed at the tip of the convex portion 54, and a fluid supply port 42 is formed on the opposite surface of the convex portion 54. The first fixed throttle 50 made of a capillary hole is perforated so as to communicate the lower pocket 48 and the fluid supply port 42. A second chamber is formed by the movable object 14 and the lower pocket 48 on the fluid outflow side of the first fixed throttle 50. The bearing body lower part 10B further includes a fluid discharge path 66 that communicates the outer peripheral surface of the bearing body lower part 10B and the bottom part of the annular pocket 56, an outer peripheral surface opposite to the outlet of the fluid discharge path 66, and a fluid supply port 42. The flow path 64 which connects is formed.
[0019]
Next, the operation of the variable throttle hydrostatic bearing of the present embodiment will be described.
[0020]
As shown in FIG. 3, the fluid entering from the fluid supply path 42 passes through the first fixed throttle 50 and enters the lower pocket portion 48. Thereafter, the fluid is divided into the following three directions. The first flow direction of the fluid passes through the second fixed throttle 40 formed in the movable object 14, flows out into the upper pocket 34, enters the upper pocket 20 through the throttle movable part 22, and then enters the gap 18. It is discharged outside the bearing through. The second flow direction of the fluid passes through the gap 68 under the movable object 14, enters the annular pocket 56, and is discharged from the fluid discharge path 66. The third flow direction of the fluid flows out to the side pocket 36 through the third fixed restrictor 38, flows out to the gap 32 between the inner wall of the bearing body upper part 10 </ b> A and the movable object 14, and then annularly It flows into the pocket 48 and is discharged from the fluid discharge path 66.
[0021]
Now, when the load of the load shaft 16 increases from a certain balanced state, the load shaft 16 is displaced downward from the state shown in FIG. Then, the gap 18 becomes narrower, and the flow rate of the fluid passing through the gap 18 decreases, so that the pressure in the first chamber increases. Due to this increase in pressure, the movable object 14 is pushed downward.
[0022]
When the movable object 14 is pushed downward, the movable object 14 moves downward in the diaphragm movable part 22, but the balance of the movable object in the floating state is lost, so that it contacts or collides with the inner wall surface of the upper bearing body 10 </ b> A. While moving down. When the movable object 14 is pushed downward, the gap between the lower gap 68 and the convex portion 54 of the movable object 14 becomes narrow, and the fluid discharge flow rate decreases. As a result, the pressure in the second chamber increases, and most of the fluid flowing out from the first fixed throttle 50 flows into the third fixed throttle 38 and the second fixed throttle 40. The fluid that has flowed into the second fixed throttle 40 flows out into the upper pocket portion 20 and increases the pressure in the first chamber to prevent the load shaft 16 from being displaced.
[0023]
The fluid that has flowed into the third fixed throttle 38 flows into the side pocket 36 and flows into the gap 32. The fluid that has flowed into the gap 32 forms a fluid film between the inner wall of the bearing body upper portion 10A and the movable object 14, and a buffer when the movable object 14 contacts or collides with the inner wall surface of the bearing body upper portion 10A. It becomes a material, suppresses wear and damage of the bearing body upper part 10A and the movable object 14, and ensures a smooth operation of the movable object 14.
[0024]
As described above, the third fixed throttle 38 is provided on an infinitely rigid bearing composed of a plurality of throttles, which theoretically does not change the gap between the load shaft and the bearing even when the load changes. The fluid flows between the object 14 and the inner wall surface of the bearing body upper part 10A to form a fluid film, and the bearing body upper part when the load from the load shaft changes or the second fixed throttle moves. Damage or wear due to contact with 10A can be suppressed.
[0025]
FIG. 4A shows a graph comparing the relationship between the load capacity W of the bearing and the load capacity Wf in the lateral direction when the third fixed throttle 38 is formed and when it is not formed. From this graph, when the third fixed throttle 38 is formed, a linear relationship is obtained in which the lateral load capacity increases in proportion to the load capacity of the bearing, and the third fixed throttle 38 is formed. If not, it can be seen that the load capacity in the lateral direction hardly changes even if the load capacity of the bearing increases. Also from this result, it can be seen that by forming the third fixed throttle 38, damage and wear of the inner surface of the movable object 14 and the upper portion 10A of the bearing body can be suppressed.
[0026]
FIG. 4B is a graph showing the relationship between the load capacity W of the bearing and the load capacity Wf in the lateral direction when the capillary diameter of the third fixed throttle 38 is changed. When the capillary diameter is 0.10 mm, the load capacity Wf in the lateral direction with respect to the load capacity W of the bearing is the largest, and when the capillary diameter is 0.20 mm, the load capacity Wf in the lateral direction has a capillary diameter of 0.10 mm. About half of the case. And when a capillary diameter is 0.30 mm or more, it turns out that the load capacity Wf of a horizontal direction becomes an extremely low value compared with the case where a capillary diameter is 0.10 mm. Therefore, the capillary diameter of the third fixed diaphragm 38 is preferably 0.10 mm to 0.20 mm.
[0027]
FIG. 4C shows the relationship between the clearance 18 between the load shaft 16 and the bearing body 10 = h2 and the clearance 68 = h1 between the first fixed throttle 50 and the movable object 14 and the load capacity W of the bearing. It is a graph to show. Here, “Ps” indicates the fluid pressure from the fluid supply port 42, but it can be seen that both h1 and h2 are not affected by Ps and take a specific value with respect to the load capacity of the bearing.
[0028]
Moreover, the variable throttle hydrostatic bearing of the present invention can be a variable throttle hydrostatic bearing having a configuration different from that of the variable throttle hydrostatic bearing of the above-described embodiment. A variable throttle hydrostatic bearing having another configuration will be described as a second embodiment with reference to the drawings. In addition, the same code | symbol is attached | subjected and demonstrated about the same part as the variable throttle type hydrostatic bearing of 1st Embodiment.
[0029]
[Second Embodiment]
As shown in FIG. 5, a fluid supply port 42 and a fluid discharge path 66 are formed in the bearing body 10 of the variable throttle hydrostatic bearing 12, and an object 50 </ b> A in which the first fixed throttle 50 is formed. A movable object 14 is built in. In the fixed object 50A, a lower pocket 46 is formed on the fluid outflow side, and a first fixed throttle 50 is formed so as to penetrate the upper and lower surfaces. The movable object 14 has an upper pocket 20 formed on the fluid outflow side, and a second fixed throttle 40 formed by a capillary hole so as to penetrate the upper and lower surfaces. Further, side pockets 36 are formed at four equally spaced positions on the outer peripheral side surface of the movable object 14, and a third fixed throttle 38 is formed so as to communicate with the side pocket 36 from the fluid inflow side of the movable object 14. Is formed. The load shaft 16 and the variable throttle hydrostatic bearing 12 are disposed with a gap 18 therebetween, and the upper pocket 20 side is in contact with the load shaft 16 through the gap 18.
[0030]
Since the operation of the variable throttle hydrostatic bearing of the present embodiment is the same as that of the variable throttle hydrostatic bearing of the first embodiment described above, description thereof is omitted.
[0031]
Also in the present embodiment, since the fluid film is formed by the fluid flowing out from the third fixed throttle 38 in the gap 32 between the inner wall surface of the bearing body 10 and the movable object 14, the movable object 14 It becomes a shock absorbing material for collision and contact with the inner wall surface of the bearing body 10 at the time of displacement, and damage and wear of the movable object 14 and the inner wall of the bearing body 10 can be suppressed.
.
[0032]
In the two embodiments described above, examples of thrust bearings have been described, but the present invention can also be applied to journal bearings. That is, for the journal bearing as well, by providing a flow path in the second fixed throttle, a fluid is flowed between the second fixed throttle and the inner wall surface of the bearing body to form a fluid film. It is possible to reduce damage, wear, etc. due to contact with the bearing main body when the second fixed throttle made of is moved. FIG. 6 shows an outline of an example in which the variable throttle hydrostatic bearing of the second embodiment is applied to a journal bearing.
[0033]
In the above-described two embodiments, the capillary aperture is used as the first fixed throttle and the second fixed throttle. However, the first fixed throttle and the second fixed throttle are formed on the porous object. It is also possible to use a narrowed aperture. In addition, it is also possible to use a capillary aperture as a first fixed aperture and a porous aperture formed in a porous object as a second fixed aperture. It is also possible to use a restriction by a capillary hole as a second fixed restriction by using a restriction by a porous formed in the object. Schematic diagrams of examples in which the throttle is used in the variable throttle hydrostatic bearing of the second embodiment are shown in FIGS.
[0034]
FIG. 7 is an example of a thrust bearing that uses a porous diaphragm formed in a porous object in the first fixed throttle and the second fixed throttle, and FIG. 8 shows the first fixed throttle and the second fixed throttle. FIG. 9 shows an example of a journal bearing using a porous aperture formed in a porous body in the aperture, and FIG. 9 shows a case where a capillary aperture is used for the first fixed aperture and a porous object is formed in the second fixed aperture. FIG. 10 shows an example of a thrust bearing using a porous aperture, and FIG. 10 uses a capillary aperture for the first fixed aperture, and uses the aperture formed in the porous object for the second fixed aperture. FIG. 11 is an example of a thrust bearing using a porous diaphragm formed in a porous body for the first fixed throttle and a capillary diaphragm aperture for the second fixed throttle. FIG. 12 shows a porous object in the first fixed throttle. Using the aperture by the formed porous, it is an example of a journal bearing using the aperture by capillary hole to the second fixed throttle.
[0035]
As shown in FIG. 13, a journal bearing can be configured by using a plurality of the thrust bearings of the above-described embodiment.
[0036]
【The invention's effect】
As described above, according to the present invention, when the load shaft is displaced, the fluid pressure in the first chamber is increased and the movable object is displaced toward the first fixed throttle. Due to this displacement, the fluid pressure in the second chamber rises, and the fluid flowing in from the first fixed throttle flows into the first chamber through the second fixed throttle and increases the pressure to prevent displacement of the load shaft. At the same time, the fluid flowing in from the first fixed throttle flows through the third fixed throttle formed in the movable object and flows out into the gap formed between the inner wall of the bearing body and the opposed part of the movable object. Since a fluid film is formed on the surface of the movable body, the movable body and the inner wall of the bearing body are prevented from being damaged or worn due to collision or friction between the movable body and the bearing body when the movable body is displaced due to fluctuations in the load axis, etc. The effect that a proper operation can be secured is obtained.
[Brief description of the drawings]
FIG. 1 is a sectional view of a variable throttle hydrostatic bearing according to a first embodiment.
FIG. 2 is a schematic configuration diagram of a variable throttle hydrostatic bearing of the first embodiment.
FIG. 3 is an enlarged sectional view of a movable object and its surroundings according to the first embodiment.
4A is a diagram comparing the relationship between the load capacity of the bearing and the load capacity in the lateral direction when the third fixed aperture is formed and when it is not formed, and FIG. It is the figure which compared the relationship between the load capacity | capacitance of a bearing corresponding to the change of the capillary diameter of a fixed throttle, and the load capacity of a horizontal direction, (C) is the clearance gap (h2) of a load shaft and a bearing, and the 1st fixed throttle. It is a graph which shows the relationship between the clearance gap (h1) of a movable object, and the load capacity of a bearing.
FIG. 5 is a schematic sectional view of a variable throttle hydrostatic bearing according to a second embodiment.
FIG. 6 is a schematic cross-sectional view when the variable throttle hydrostatic bearing of the second embodiment is applied to a journal bearing. FIG. 7 is a schematic cross-sectional view of another example when the variable throttle hydrostatic bearing of the second embodiment is applied to a thrust bearing.
FIG. 8 is a schematic sectional view of another example in which the variable throttle hydrostatic bearing of the second embodiment is applied to a journal bearing.
FIG. 9 is a schematic cross-sectional view of another example when the variable throttle hydrostatic bearing of the second embodiment is applied to a thrust bearing.
FIG. 10 is a schematic sectional view of another example when the variable throttle hydrostatic bearing of the second embodiment is applied to a journal bearing.
FIG. 11 is a schematic sectional view of another example when the variable throttle hydrostatic bearing of the second embodiment is applied to a thrust bearing.
FIG. 12 is a schematic sectional view of another example when the variable throttle hydrostatic bearing of the second embodiment is applied to a journal bearing.
FIG. 13 is a schematic sectional view of a journal bearing constituted by using a plurality of variable throttle hydrostatic bearings of a second embodiment.
FIG. 14 is an example of a conventional variable throttle hydrostatic bearing.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Bearing main body 12 Variable throttle-type hydrostatic bearing 14 Movable object 16 Load shaft 18 Clearance 20 Upper pocket 22 Restriction movable part 24 Lower pocket 26 Pressure gauge 32 Clearance 34 Upper pocket 36 Side pocket 38 Third fixed restriction 40 Second Fixed throttle 42 Fluid supply port 46 Passage 48 Lower pocket 50 First fixed throttle 54 Protrusion 56 Annular pocket 64 Channel 66 Fluid discharge channel 68 Clearance

Claims (8)

A fluid supply port for supplying a fluid, a first fixed throttle for restricting the flow rate of the fluid supplied from the fluid supply port to flow into the inside, and a fluid discharge port for discharging the fluid that has flowed in, A bearing body disposed at a distance from the shaft;
The bearing body is movably accommodated in the bearing body, and the bearing body is partitioned into a first chamber on the load shaft side and a second chamber communicated with the first fixed throttle and the fluid discharge port. In addition, the flow rate of at least one of the fluid flowing from the first chamber to the second chamber and the fluid flowing from the second chamber to the first chamber is reduced by communicating the first chamber and the second chamber. second fixed throttle, and the bearing body, one end of Ri down the flow of fluid to the inner wall direction of the opening to the bearing body portion facing the inner wall of the second of said opening vital other end bearing body in the room a movable object which third fixed stop that form a fluid film, is formed between the inner wall,
Variable throttle hydrostatic bearing with   2. The variable throttle hydrostatic bearing according to claim 1, wherein at least one of the first fixed throttle and the second fixed throttle is a porous throttle formed in a porous body.   2. The variable throttle hydrostatic bearing according to claim 1, wherein at least one of the first fixed throttle and the second fixed throttle is a throttle formed by a capillary hole.   2. The variable throttle hydrostatic bearing according to claim 1, wherein the first fixed throttle is a throttle by a capillary hole, and the second fixed throttle is a throttle by a porous formed in a porous object. .   2. The variable throttle hydrostatic bearing according to claim 1, wherein the first fixed throttle is a throttle by a porous formed in a porous object, and the second fixed throttle is a throttle by a capillary hole. .   2. The variable throttle hydrostatic bearing according to claim 1, wherein the first fixed throttle is a throttle based on an orifice effect.   7. A variable throttle hydrostatic bearing in which the variable throttle hydrostatic bearing according to any one of claims 1 to 6 is a thrust bearing.   A variable throttle hydrostatic bearing that constitutes a journal bearing by using a plurality of variable throttle hydrostatic bearings according to claim 7.

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