JP4806741B2 - Sphere floating device - Google Patents

Description

  The present invention relates to a spherical levitation apparatus to which a static pressure gas bearing is applied.

  Conventionally, a device that floats a sphere using pressure gas has been put into practical use, but its flow rate is as large as several tens to several hundreds [l / sec], and therefore the disturbance torque that the pressure gas gives to the sphere is large. there were. The rotational motion of the floating sphere is easily affected by the disturbance torque due to the working fluid. In applications where this is a problem, it is important to reduce the disturbance torque due to the minute differential pressure and minute flow rate. However, a comprehensive design method for the levitation device to achieve this has not been established. In addition, since compressed air can be supplied with a small-scale pump compared to the conventional system, it is desirable to realize a minute differential pressure and minute flow rate from the viewpoint of energy saving, space saving, weight reduction, high reliability, and noise reduction. .

  Conventionally, many planar bearings using static pressure gas bearings have been put into practical use, and a performance calculation method has been established by the supply throttle type (Non-Patent Document 1).

  One of the supply throttle types is a slot throttle type. This supplies air in the form of a line rather than a point in the bearing surface, and produces a uniform and unspread flow in the bearing surface. Further, a circular slot throttle gas bearing in which the slot shape is circular is conceivable, and a bearing having characteristics such as high bearing rigidity / load capacity and low flow rate / differential pressure is realized.

“Gas Bearing Handbook” by Junichi Jugo Kyoritsu Publishing

  The characteristics of the air supply throttle in the above-described plane bearing can be expected to have the same characteristics in the spherical static pressure gas bearing, but a method for calculating its performance has not been established. In planar bearings, the flying width is uniform over the entire bearing surface, but in spherical bearings, the flying width varies depending on the location of the bearing surface depending on the flying state. For this reason, it is not possible to apply the performance calculation for a plain bearing to a spherical bearing as it is.

  Further, in order to realize a bearing with a small flow rate and differential pressure by the above-described slot restriction, the slot width needs to be extremely narrow. In the conventional planar bearing, in order to realize this, there has been provided a system in which a shim having a thickness corresponding to the slot width is sandwiched between bearing members forming the slot. However, when this method is applied to a spherical bearing, there is a problem that the spherical accuracy of the bearing surface cannot be maintained. In addition, it is very difficult to produce a thin shim, and this method has its limitations.

  An object of the present invention is to provide a sphere floating device that can be operated with a minute flow rate and a minute differential pressure. For this reason, the method for calculating the bearing performance that has been used in the plane hydrostatic gas bearing is formulated so that it can be used in the spherical hydrostatic gas bearing. Furthermore, we will establish a bearing design method based on this formulation, and design a bearing that can be operated with a minute flow rate and minute differential pressure. In order to realize this design result, we propose a method of manufacturing a circular slot diaphragm with a very small width that can be easily applied to spherical bearings.

  A spherical levitation apparatus according to the present invention includes a spherical rigid body, a spherical bearing surface, a spherical static pressure gas bearing for levitating the rigid body in a non-contact manner with a pressure gas, and the spherical static pressure gas bearing. An air supply mechanism for supplying a pressure gas, and the rigid body, the spherical static pressure gas bearing and the air supply mechanism are designed on the basis of the floating width of the rigid body on the formulated bearing surface. It is characterized by that.

  The spherical hydrostatic gas bearing performance calculation method according to the present invention relates to a spherical hydrostatic gas bearing that has a spherical bearing surface and floats a spherical rigid body in a non-contact manner with a pressure gas. A step of calculating a width; a step of calculating a flow rate at the bearing surface from the flying height and a pressure distribution at the bearing surface; and a step of calculating a load capacity from the pressure distribution at the bearing surface. To do.

  A design method for a spherical levitation apparatus according to the present invention is a spherical static pressure gas bearing having a spherical rigid body and a spherical bearing surface, and for levitating the rigid body in a non-contact manner with a pressure gas. A spherical levitation device design method comprising: a spherical static pressure gas bearing in which a shape of a throttle for supplying air in a plane is an annular slot; and an air supply mechanism for supplying pressure gas to the spherical static pressure gas bearing. A step of calculating a flying height at each part of the bearing surface, a step of calculating a flow rate at the bearing surface from the flying width and a pressure distribution at the bearing surface, and a load capacity from the pressure distribution at the bearing surface. A step of calculating a bearing rigidity using the load capacity, and a supply pressure, an ambient pressure, and a spherical surface capable of achieving the calculated load capacity, the flow rate, and the bearing rigidity. Bearing radius of the gas bearing, the radius of the annular slot, the width of the annular slot, and characterized in that it comprises the steps of: determining the depth of the annular slot.

  The bearing according to the present invention is an upper member having an upper surface opening formed on a spherical upper surface and a lower surface opening formed on a lower surface, and communicates with the upper surface opening and an air supply port for taking in air from the outside. An upper member including an introduction path, an engagement hole including a tapered portion that communicates with the introduction path and the lower surface opening and increases in cross-sectional area as it proceeds downward, and has a smaller cross-sectional area than the introduction path. A cylindrical insertion part that forms an annular slot between the insertion path and the engagement hole, and is engaged with the engagement hole. A lower member including an engagement part including a taper part whose cross-sectional area increases as it progresses downward, and a base part on which the engagement part is placed on the upper surface. When substantially the entire tapered portion is covered with the tapered portion of the upper member, Gap between the lower surface of the part member and the upper surface of the base portion of the lower member is configured to be formed, characterized in that.

The bearing according to the present invention is an upper member having an upper surface opening formed on a spherical upper surface and a lower surface opening formed on a lower surface, and communicates with the upper surface opening and an air supply port for taking in air from the outside. An upper member including an introduction path, and an engagement hole including a tapered portion that communicates with the introduction path and the lower surface opening and increases in cross-sectional area as it progresses downward;
A cylindrical insertion portion having a smaller cross-sectional area than the introduction path and forming an annular slot between the introduction path by being inserted into the introduction path through the engagement hole, and the insertion And a lower member including an engaging portion including a tapered portion whose cross-sectional area increases as it proceeds downward so as to be engaged with the engaging hole.

  The bearing manufacturing method according to the present invention is an upper member in which an upper surface opening is formed on a spherical upper surface and a lower surface opening is formed on a lower surface, and the upper surface opening and an air supply port for taking in air from the outside. Producing an upper member including an introduction path that communicates, and an engagement hole including a tapered portion that communicates with the introduction path and the lower surface opening and increases in cross-sectional area as it proceeds downward; and A cylindrical insertion portion having a smaller cross-sectional area and inserted into the introduction passage through the engagement hole to form an annular slot between the introduction passage and the insertion portion coupled to the insertion portion. An engaging portion including a tapered portion whose cross-sectional area increases as it advances downward so as to engage with the engaging hole, and substantially the entire tapered portion covers the tapered portion of the engaging hole of the upper member. Engagement member having a gap forming portion extending from the engagement hole when broken And a step of manufacturing a lower member including a base portion on which the engaging portion is placed on the upper surface, and substantially the entire tapered portion of the engaging portion is covered with the tapered portion of the engaging hole. And combining the upper member and the lower member, and tightening the lower surface of the upper member and the base portion of the lower member with a screw.

  The bearing manufacturing method according to the present invention is an upper member in which an upper surface opening is formed on a spherical upper surface and a lower surface opening is formed on a lower surface, and the upper surface opening and an air supply port for taking in air from the outside. Producing an upper member including an introduction path that communicates, and an engagement hole including a tapered portion that communicates with the introduction path and the lower surface opening and increases in cross-sectional area as it proceeds downward; and A cylindrical insertion part having a smaller cross-sectional area and inserted into the introduction path through the engagement hole to form an annular slot with the introduction path, and coupled to the insertion part A lower member including an engagement portion including a taper portion whose cross-sectional area increases as it proceeds downward to engage with the engagement hole, and the taper portion of the engagement portion is the engagement portion. The upper member and the front to engage the taper of the hole Characterized in that it comprises the steps of: combining the lower member.

  In the present invention, the bearing width is calculated by treating the flying height of the spherical bearing and the load capacity with respect to the pressure distribution as parameters depending on the phase from the vertically downward direction on the bearing surface. The formulation method is shown concretely.

ここでｈは軸受面最下面７における浮上幅である。これを解くと、関数ｈ^*は次式のように表される。

この関数ｈ^*(θ)は、ｈがＲに比して十分小さい場合、以下のように近似して計算しても誤差は十分小さく、軸受性能の計算にはほとんど影響しない。

負荷容量は、浮上球１に加わる圧力の上向きの成分を軸受面２全体で積分することにより求められる。軸受面２上で浮上球１に加わる圧力はその球面に垂直に加わることから、負荷容量は次式で計算される。

ここでθ_aは軸受最下面７に対する軸受端８の位相、ｐ_aは周辺圧力である。 In planar bearings, the flying width is constant at various locations on the bearing surface. However, in a spherical bearing, the flying width varies depending on the location of the bearing surface, and also varies depending on the radius of curvature of the bearing surface and the radius of the ball to be floated. Here, it is assumed that the radius of curvature of the bearing surface coincides with the radius R of the ball to be levitated, and the center of the levitating ball comes directly above the center of the bearing surface. Therefore, consider the relationship between the floating ball 1 and the bearing surface 2 as shown in FIG. The flying width h ^* is a function of the phase difference θ from the lowermost surface portion 7 of the bearing surface. When the cosine theorem is applied to the hatched triangle in FIG. 1, the following relational expression is obtained.

Here, h is the flying width on the lowermost bearing surface 7. Solving this, the function h ^* is expressed as:

If h is sufficiently smaller than R, the function h ^* (θ) has a sufficiently small error even if it is approximated as follows, and hardly affects the calculation of the bearing performance.

The load capacity is obtained by integrating the upward component of the pressure applied to the floating ball 1 over the entire bearing surface 2. Since the pressure applied to the floating ball 1 on the bearing surface 2 is applied perpendicularly to the spherical surface, the load capacity is calculated by the following equation.

Here theta _a is the bearing end 8 with respect to the bearing bottom surface 7 phase, the p _a is ambient pressure.

  If the above spherical bearing formulation is used, it is possible to extend and use the conventionally proposed performance calculation method for a flat bearing as it is. Here, as an example, the performance of a spherical bearing using a circular slot throttle thrust bearing is calculated.

ここで、ｑ_xはx方向の流れにおける流量、Ｂは流路幅、ｈは浮上幅、μは気体の粘性係数、ｐは圧力である。 From Non-Patent Document 1, the flow rate derivation formula for the viscous flow flowing through the narrow gap below is used to calculate the bearing performance.

Here, q _x is a flow rate in the flow in the x direction, B is a flow path width, h is a flying width, μ is a viscosity coefficient of gas, and p is a pressure.

  FIG. 2 is a schematic sectional view of a spherical static pressure gas bearing using a circular slot diaphragm. In the bearing using this throttle type, the flow in the slot 3 from the chamber 4 to the throttle outlet 6 is defined as the flow in the coaxial cylindrical parallel gap, and the flow on the bearing surface 2 from the throttle outlet 6 to the bearing end 8 is defined as the flow. It can be treated as a radial flow in a spherical gap. For each of these, the flow rate of the flow in each gap is determined from the air supply condition and the design condition.

ここで、ｈ_slはスロット幅、ｌ_slはスロット深さ、ｐ_sは給気口５における圧力、ｐ₀は絞り出口６における圧力、Ｒ_aは一般気体定数、Ｔは温度である。 First, the flow rate in the slot 3 is obtained as follows.

Here, h _sl is the slot width, l _sl is the slot depth, p _s is the pressure at the inlet 5, p ₀ is the pressure at the throttle outlet 6, R _a is the general gas constant, and T is the temperature.

ここで、θ₀は軸受最下面７に対する絞り出口６の位相であり、またＦ(θ)は、以下に示すｆ(θ)の積分関数である。

Ｆ(θ)を解析的に求めることは困難である。しかし、ｈがＲに比して十分小さい場合、ｆ(θ)を以下のように近似して用いることにより、解析的に求めることは可能となる。

この近似を用いると、Ｆ(θ)は以下のように求められる。

軸受内の流れに対する連続条件により、(6)、(7)式から次式が得られる。

ただし、

である。この絞り出口圧力が与えられれば、(6)あるいは(7)式に代入することで流量を計算することができる。 Next, the flow rate on the bearing surface 2 is obtained. The flying width h ^{* at} various locations on the bearing surface is a function of θ as determined by equation (2). When this function h ^* (θ) is used, the flow rate on the bearing surface 2 is obtained by the following equation.

Here, θ ₀ is the phase of the throttle outlet 6 with respect to the bearing lowermost surface 7, and F (θ) is an integral function of f (θ) shown below.

It is difficult to analytically determine F (θ). However, when h is sufficiently smaller than R, it can be obtained analytically by approximating f (θ) as follows.

Using this approximation, F (θ) can be obtained as follows.

The following equation can be obtained from equations (6) and (7) depending on the continuous conditions for the flow in the bearing.

However,

It is. If this throttle outlet pressure is given, the flow rate can be calculated by substituting into the equation (6) or (7).

ただし、θ＜θ₀においてはｐ＝ｐ₀で一定であるとする。 Next, calculate the pressure distribution on the bearing surface 2 from the stop outlet pressure p ₀ and ambient pressure p _a.
However, it is difficult to actually calculate the pressure distribution. Here, the pressure p (θ) is approximated as a linear function of θ. That is,

However, it is assumed that p = p ₀ is constant when θ <θ ₀ .

軸受剛性は浮上幅ｈの増加量に対する負荷容量の減少量の割合である。すなわち、

で求めることができる。 負荷容量の計算の場合と同様に(9)の近似式を用いた場合、(14)式をｈで微分することにより軸受剛性は以下の式で計算できる。

ここで、

である。 By substituting this pressure distribution into equation (4), the load capacity can be obtained. When the approximate expression (9) is used, the load capacity can be specifically calculated by the following expression.

The bearing rigidity is the ratio of the decrease amount of the load capacity to the increase amount of the flying width h. That is,

Can be obtained. As in the case of calculating the load capacity, when the approximate expression (9) is used, the bearing rigidity can be calculated by the following expression by differentiating the expression (14) by h.

here,

It is.

As described above, the supply pressure p _s, ambient pressure p _a, throttle outlet phase theta _0, bearing end phase theta _a, slot width h _sl, slot depth l _sl, the floating width h as parameters, flow rates, bearing It is possible to calculate the load capacity, that is, the mass of the ball that can be levitated and the bearing rigidity. As an actual design procedure, p _s , p _a , θ ₀ , θ _a , h _sl , and l _sl are fixed and h is changed around the target design value to calculate the flow rate, load capacity, and bearing stiffness. .

  Here, a method for calculating the bearing performance in the case of the slot throttle type is presented, but this method can also be applied to other throttle shapes, for example, a self-contained throttle or a point supply bearing of an orifice throttle. The new part of this method is to formulate the flying width on the spherical bearing surface and provide a method to calculate the load capacity, flow rate, and bearing rigidity from the pressure distribution on the spherical bearing surface. It is applicable regardless.

  The throttle type of a normal bearing such as a self-contained throttle or an orifice throttle is a point-like air supply hole, whereas the slot throttle supplies air linearly. In the spherical thrust bearing, the concentric pressure distribution is formed by arranging the throttles in a circular shape, and a substantially uniform flow can be formed radially. As a result, the load capacity can be increased efficiently with respect to the supply air pressure. Conversely, the supply air pressure required to obtain the target load capacity is small, and at the same time the flow rate can be reduced. By applying the slot restriction to the spherical bearing in this way, it is possible to float the ball with a minute differential pressure and a minute flow rate.

  The viscous force caused by the gas flowing on the spherical bearing gives a rotational disturbance to the sphere. However, since the air supply condition with a minute differential pressure and a minute flow rate is achieved, a stable uniform flow dominates on the bearing surface, and the viscous torque exerted on the sphere by this flow can be reduced.

  Based on the bearing performance calculation in which the circular slot diaphragm is applied to a spherical bearing, it can be seen that the flying height should be designed to be as small as possible in order to obtain a minute flow rate, minute differential pressure, and high rigidity. However, in order to configure a flow path that creates a uniform flow on the bearing surface even with a small flying width, both the bearing surface and the rigid sphere need to be finished with high accuracy. Further, in order to realize a bearing that reduces the flying width, it is necessary to reduce the slot width as much as possible. In order to construct a flow path that creates a uniform flow in a circular slot, it is necessary to achieve a uniform width over the entire circumference. In the manufacture of such a bearing having a high precision bearing surface and a small annular slot having a uniform width over the entire circumference, the problems in the conventional mechanical design and machining techniques have been solved as follows.

  In the member inside the slot and the member outside the slot forming the circular slot stop, the slot width is expressed by the difference between the outer peripheral radius inside the slot and the inner peripheral radius outside the slot. In order to make the slot width of the circular slot very small and uniform over the entire circumference, it is necessary to keep the central axis of the inner member of the slot and the central axis of the outer member of the slot coincide with each other with high accuracy. In the present invention, as shown in FIG. 3, in order to make the center axes of the members of the slot inner side 9 and the slot outer side 10 coincide with each other with high accuracy, the mating portion 11 of both is tapered. As a result, the slot width can be easily made uniform over the entire circumference.

Actually, it is difficult to machine finish the taper portion mating surfaces 11 of the slot inner side 9 and the slot outer side 10 to the completely same taper angle.
Therefore, the present invention employs a system in which a gap 13 of about 0.1 mm is provided at the straight joint 12 between the slot inner side 9 and the slot outer side 10 and both are adjusted by screwing 14 at several places. Actually, air is supplied from the air supply port 5, and the air discharged from the slot is finely adjusted at several locations while confirming the size of the bubbles in the water. The air discharge amount in the part was made uniform.

  By this method, the taper portion mating surface 11 of the slot inner side 9 and the slot outer side 10 can be completely coupled, and a slight air leakage at the taper portion can be prevented, so that the air discharge becomes stable.

  In the spherical bearing, the spherical shape of the bearing surface 2 is broken by adjusting the positions of the slot inner side 9 and the slot outer side 10. Therefore, in the present invention, a method of adjusting the positional relationship between the slot inner side 9 and the slot outer side 10 and then assembling and then finishing the bearing surface 2 by integral machining is employed. Thereby, a spherical shape can be realized with high accuracy.

  The approximation of the flying width adopted in the formulation of the bearing performance was calculated on the assumption that the radius of the flying ball 1 and the radius of curvature of the bearing surface 2 coincide. When the radius of the levitating sphere 1 and the radius of curvature of the bearing surface 2 are different, there is a problem that the pressure distribution varies depending on the levitating width, and the gas flow becomes unstable when ascending. In the present invention, the bearing surface 2 is lapped (polished) so that the radius of the floating ball 1 and the radius of curvature of the bearing surface 2 coincide with each other with high accuracy. Thereby, the radius of the floating sphere 1 and the curvature radius of the bearing surface 2 coincide with each other with high accuracy, and the gas flow on the spherical bearing can be stabilized.

  Here, the configuration of the spherical static pressure gas bearing shown in FIG. 3 can be expressed by another expression as follows.

The spherical static pressure gas bearing 100 includes an upper member 200 and a lower member 300 combined therewith.
The upper member 200 has a cylindrical shape with a through hole formed therein. The upper surface 201 of the upper member 200 is formed in a spherical shape. An opening (upper surface opening) 202 is formed on the upper surface 201. An opening (lower surface opening) 204 is also formed in the lower surface 203. The upper member 200 is formed with a through hole that allows the upper surface opening 202 and the lower surface opening 204 to communicate with each other.

  Such a through hole includes an introduction path 206 that communicates with the upper surface opening 202 and an air supply port 205 that takes in air from the outside. The through hole further includes an engagement hole 207 communicating with the introduction path 206. The engagement hole 207 includes a tapered portion 207a having a cross-sectional area that increases as it proceeds downward (the tapered portion 207a forms the mating surface 11), and a portion 207b having a constant cross-sectional area. . The engagement hole 207 communicates with the lower surface opening 204.

  The lower member 300 has a smaller cross-sectional area than the introduction path 206 of the upper member 200, and a columnar insertion section 301 that is inserted into the introduction path 206 through the engagement hole 207, and is coupled to the insertion section 301. An engaging portion 302 formed to engage with the joint hole 207 and a base portion 304 for placing the engaging portion 302 on the upper surface 303 are included.

The insertion portion 301 is inserted into the introduction path 206 of the upper member 200, thereby forming an annular slot 3 between the insertion section 301 and the introduction path. A portion 301 a having a smaller cross-sectional area than other portions of the insertion portion is formed between the upper end and the lower end of the insertion portion, and this portion 301 a forms the chamber 4 together with the introduction path 206. The chamber 4 communicates with the air supply port 205.
Further, the upper surface 301 b of the insertion portion 301 is configured to form a spherical surface together with the upper surface 201 of the upper member 200.

  The engaging portion 302 is coupled to the lower end of the insertion portion 301 at the upper end thereof. The engaging portion 302 is formed to include a tapered portion 302a (the tapered portion 302a forms the mating surface 11) whose cross-sectional area increases as it goes downward. The tapered portion 302a is formed so as to engage with the tapered portion 207a of the upper member 200 and its outer peripheral surface substantially coincides with the inner peripheral surface of the tapered portion 207a.

  Further, the engaging portion 302 includes a portion 302b coupled to the tapered portion 302 and having a substantially constant cross-sectional area. The portion 302b is configured to extend to the outside of the engagement hole of the upper member 200 when substantially the entire tapered portion 302a is covered with the tapered portion 207a of the upper member 200. A portion (gap forming portion) extending to the outside of the engagement hole of the upper member 200 in this portion 302b provides the above-described gap 13, that is, the gap 13. Therefore, the size of the gap 13 can be changed by adjusting the height of the portion 302b of the engaging portion 302, for example.

  Furthermore, the lower surface 203 of the upper member 200 and the base portion 304 of the lower member 300 have screw holes 208 and 305 through which screws for tightening the upper member 200 and the lower member 300 to change the size of the gap 13 are passed. Is formed.

  In FIG. 3, tapered portions 207 a and tapered portions 302 a are formed in the upper member 200 and the lower member 300, respectively, so that the central axis of the introduction path 206 of the upper member 200 and the central axis of the insertion portion 301 of the lower member 300 are formed. Is a spherical static pressure gas bearing that implements both a configuration (taper processing method) that matches with a high precision and a configuration (gap processing method) in which a gap 13 is provided in order to realize perfect coupling of these taper portions (gap processing method). Although shown as the best mode of the present invention, the present invention is not limited to this, and includes a spherical static pressure gas bearing that performs only the taper processing method.

  A spherical hydrostatic gas bearing is manufactured by assembling the upper member 200 and the lower member 300 having such a configuration in accordance with the following procedure.

  First, the upper member 200 and the lower member 300 having the above-described configuration are individually manufactured. Next, the upper member 200 and the lower member 300 are combined so that substantially the entire tapered portion 302a of the lower member 300 is covered by the tapered portion 207a of the upper member 200. As a result, only part of the portion 302 b (that is, the gap forming portion) of the engaging portion 302 of the lower member 300 extends to the outside of the engaging hole of the upper member 200. As a result, a gap is formed between the lower surface 203 of the upper member 200 and the upper surface 304 of the base portion 304 of the lower member 300.

  Thereafter, screws are inserted into the screw holes 208 of the upper member 200 and the screw holes 305 of the lower member 300, and the upper member 200 and the lower member 300 are tightened together. By adjusting this tightening, the central axis of the tapered portion 207a of the upper member 200 and the central axis of the tapered portion 302a of the lower member 300 (and consequently the central axis of the introduction path 206 and the central axis of the insertion portion 301) are increased. Can be adjusted with accuracy. As a result, the width of the annular slot 3 formed between the introduction path 206 and the insertion portion 301 can be made uniform with high accuracy.

  When performing such tightening, air can be supplied from the air supply port 205 to the upper member 200 of the upper member 200 and the upper surface opening 202 of the upper member 200 can be immersed in water. As a result, the width of the annular slot 3 can be adjusted with higher accuracy by finely adjusting the tightening of the screw according to the amount of air discharged from the upper surface opening 202 through the annular slot 3.

  After such tightening is completed, a polishing process is performed on the spherical surface formed by the upper surface 201 of the upper member 200 and the upper surface 301b of the insertion portion 301 of the lower member 300.

  In order to calculate the performance of the sphere levitation device, a spherical bearing was mathematically formulated. This enables quantitative design to achieve the required performance.

  By applying the circular slot throttle thrust bearing employed in the present invention, an unprecedented low turbulence torque ball floating device can be realized. This makes it possible to apply a sphere having a three-dimensional rotational degree of freedom to a target to be precisely controlled with higher accuracy. In addition, the scale of the pump for operating the levitation device can be reduced, which is more advantageous than the conventional one in terms of energy saving, space saving, weight reduction, high reliability, and noise reduction. For example, a piezoelectric vibration pump can also be applied to a spherical levitation apparatus that conventionally requires a mechanical pump, and the application range is very wide.

  From the viewpoint of machining / accuracy management technique, ensuring the machining accuracy of the disk-shaped slot throttle thrust bearing, which was difficult to apply to spherical bearings, can be easily realized by the machining technique / mechanism presented in the present invention. became. This can also be applied to conventional planar bearings, and it has become possible to easily ensure the machining accuracy as well.

As an example, FIG. 4 shows an example of an apparatus for levitating a steel ball having an 11/8 inch diameter manufactured as a testing machine for an attitude control device (three-dimensional spherical reaction wheel) of an artificial satellite. FIG. 4 is a cross-sectional view including an air supply port. The gas flowing in from the air supply port 5 by the pump is supplied to the slot 3 arranged in a cylindrical shape via the ring-shaped chamber 4. When the gas is ejected from the slot 3 into the bearing surface 2, the gas spreads radially on the bearing surface 2 and is released at the bearing end 8. The design parameters of this prototype are: throttle aperture phase θ ₀ is 27.27 [deg], bearing end phase θ _a is 66.38 [deg], slot depth l _sl is 10 [mm], and slot width h _sl is 5 [μm]. It is. Under this design condition, when the supply air pressure p _s was 0.03 [MPa], the steel ball surfaced. At this time, the flow rate M was 0.016 [l / min]. Regarding the relationship between supply pressure and flow rate, it is known that the theoretical value obtained by the formulation in the present invention and the experimental value obtained by the manufactured device are in good agreement, and it is confirmed that the performance can be estimated at the design stage. is made of.

  In the production of the prototype, as shown in the exploded view of FIG. 5, the inner slot 9 and the outer slot 10 are assembled together with the tapered surface 11. As a result, the central axes of the inner slot 9 and the outer slot 10 were made identical, and the groove width 5 [μm] of the slot 3 was successfully achieved uniformly over the entire circumference. After that, the assembled bearing surface 2 was subjected to integral machining and finished by lapping, thereby realizing a highly accurate spherical surface that stabilizes the flow of the entire bearing surface 2.

  Although the case where the width of the slot 3 is 5 [μm] has been described as an example, the present invention is not limited to this. In order to realize a minute flow rate, minute differential pressure, and high rigidity, it is necessary to design the flying width as small as possible, and in order to realize this, it is necessary to design the slot width as much as possible. On the other hand, if the flying width and slot width are designed to be extremely small, the influence of work errors increases, and the expected performance cannot be obtained. In this prototype, the bearing performance that enables operation with a piezoelectric vibration pump is realized, and the design value that does not increase the influence of machining errors is set to a slot 3 width of 5 [μm]. The performance close to the value obtained in step 1 was obtained.

  The present invention includes a robot arm joint, a low-disturbance mechanical gyroscope, an inertial specification measurement device, a three-dimensional free motion simulation device (weightless simulation), an artificial satellite attitude control device, an ultra-precision linear guide, an anti-seismic and vibration-proof device, Amusement park playground equipment, non-contact parallel link mechanism, ultra-precision surface plate, slight contact-sensitive revolving door, small contact-sensitive revolving stage, work table, trackball (thing with mouse ball on top) ), Omnidirectional mobile trolley, large speaker stand (anti-vibration use), and other nursing, health and medical equipment.

  As an example, a specific example in which the present invention is applied to a non-contact parallel link mechanism device will be described with reference to FIG.

  FIG. 6A is a schematic diagram showing a configuration of a non-contact parallel link mechanism using a spherical static pressure gas bearing according to the present invention, and FIG. 6B is a non-contact diagram shown in FIG. 6A. It is an exploded view which shows the structure of a parallel link mechanism.

  As shown in FIG. 6A, the non-contact parallel link mechanism mainly includes a plate-like table 601, a plate-like base 602, and a plurality of support mechanisms 603. In FIG. 6A, three support mechanisms 603 are used as an example of the plurality of support mechanisms 603.

  As shown in FIG. 6B, the support mechanism 603 includes a support column 603a and one floating ball 603b and two bearing support columns 603c disposed between the support column 603a, the table 601, and the base 602, respectively. Including. A spherical static pressure gas bearing according to the present invention is used as the bearing post 603c.

  Similar to a general parallel link mechanism, the non-contact parallel link mechanism shown in FIG. 6 controls a plurality of link mechanisms, that is, the support mechanisms 603 in parallel, and moves one point (that is, the movement of the table 601). ) Can be decided.

  Furthermore, according to the non-contact parallel link mechanism shown in FIG. 6, the floating mechanism 603b and the bearing post 603c are not in contact with each other in the link mechanism, that is, the support mechanism 603, thereby realizing a link mechanism having no frictional resistance. Can do. Therefore, the non-contact parallel link mechanism using the spherical static pressure gas bearing according to the present invention has a large industrial application.

It is explanatory drawing of the floating width in a spherical bearing. It is a schematic diagram of a circular slot throttle thrust spherical bearing. It is a schematic diagram which shows the structure of the spherical surface static pressure gas bearing which concerns on this invention. It is sectional drawing which shows the structure of the attitude | position control apparatus using the spherical surface static pressure gas bearing which concerns on this invention. It is an exploded view which shows the structure of the attitude | position control apparatus using the spherical surface static pressure gas bearing which concerns on this invention. It is a schematic diagram which shows the structure of the non-contact parallel link mechanism using the spherical surface static pressure gas bearing which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Floating ball 2 Bearing surface 3 Slot 4 Chamber 5 Air supply port 6 Restriction outlet 7 Bearing bottom surface 8 Bearing end 9 Slot inner side 10 Slot outer side 11 Matching surface 12 Linear coupling part 13 Clearance (gap)
14 Screwing

Claims (12)

A spherical rigid body, a spherical bearing surface having a spherical shape, and a spherical static pressure gas bearing for levitating the rigid body in a non-contact manner with a pressure gas; and an air supply mechanism for supplying pressure gas to the spherical static pressure gas bearing , And
The rigid, the spherical externally pressurized gas bearing and the air supply mechanism, which has been designed based on the floating width of the rigid in the bearing surface that is formulated,
The flow rate, load capacity and bearing rigidity of the spherical hydrostatic gas bearing are calculated using the flying width,
In the spherical static pressure gas bearing, the shape of the throttle for supplying air into the bearing surface is an annular slot,
The spherical hydrostatic gas bearing is
An upper member having an upper surface opening formed on a spherical upper surface and a lower surface opening formed on a lower surface, the introduction path communicating with the upper surface opening and an air supply port for taking in air from outside, and the introduction An upper member including an engagement hole including a tapered portion that communicates with the path and the lower surface opening and increases in cross-sectional area as it proceeds downward;
A cylindrical insertion portion having a smaller cross-sectional area than the introduction path and forming an annular slot between the introduction path by being inserted into the introduction path through the engagement hole, and the insertion A lower member including an engaging portion including a tapered portion that is coupled to the portion and has a cross-sectional area that increases in a downward direction so as to engage with the engaging hole;
Comprising
A sphere floating device characterized by the above. A spherical hydrostatic gas bearing having a spherical bearing surface, for floating a spherical rigid body in a non-contact manner with a pressure gas ,
An upper member having an upper surface opening formed on a spherical upper surface and a lower surface opening formed on a lower surface, the introduction path communicating with the upper surface opening and an air supply port for taking in air from outside, and the introduction An upper member including an engagement hole including a tapered portion that communicates with the path and the lower surface opening and increases in cross-sectional area as it proceeds downward;
A cylindrical insertion portion having a smaller cross-sectional area than the introduction path and forming an annular slot between the introduction path by being inserted into the introduction path through the engagement hole, and the insertion A lower member including an engaging portion including a tapered portion that is coupled to the portion and has a cross-sectional area that increases in a downward direction so as to engage with the engaging hole;
For spherical static pressure gas bearings with
Calculating the flying width at various locations on the bearing surface;
Calculating the flow rate at the bearing surface from the flying width and the pressure distribution at the bearing surface;
Calculating a load capacity from a pressure distribution on the bearing surface;
A method for calculating the performance of a spherical hydrostatic gas bearing, comprising: The performance calculation method according to claim 2 , further comprising a step of calculating bearing rigidity using the load capacity. A spherical static pressure gas bearing having a spherical rigid body and a spherical bearing surface, and for floating the rigid body in a non-contact manner with a pressure gas, wherein the shape of the throttle for supplying air into the bearing surface is an annular slot. A spherical static pressure gas bearing, and an air supply mechanism for supplying pressure gas to the spherical static pressure gas bearing. An upper member having a lower surface opening formed on the lower surface, wherein the upper surface opening communicates with the air supply port for taking in air from the outside, and communicates with the introduction path and the lower surface opening. An upper member including an engagement hole including a tapered portion whose cross-sectional area increases in the downward direction, and has a smaller cross-sectional area than the introduction path, and is inserted into the introduction path through the engagement hole. Columnar insertion to form an annular slot with the introduction path And a lower member including an engagement portion including a taper portion coupled to the insertion portion and having a cross-sectional area that increases in a downward direction so as to engage with the engagement hole. A method for designing a configured sphere levitation device, comprising:
Calculating the flying width at various locations on the bearing surface;
Calculating the flow rate at the bearing surface from the flying width and the pressure distribution at the bearing surface;
Calculating a load capacity from a pressure distribution on the bearing surface;
Calculating a bearing stiffness using the load capacity;
The calculated load capacity, the flow rate and the bearing stiffness, the supply pressure, the ambient pressure, the bearing radius of the spherical hydrostatic gas bearing, the radius of the annular slot, the width of the annular slot, and Determining the depth of the annular slot;
A method for designing a sphere levitation device, comprising: An upper member having an upper surface opening formed on a spherical upper surface and a lower surface opening formed on a lower surface, the introduction path communicating with the upper surface opening and an air supply port for taking in air from outside, and the introduction An upper member including an engagement hole including a tapered portion that communicates with the path and the lower surface opening and increases in cross-sectional area as it proceeds downward;
A cylindrical insertion portion that has a smaller cross-sectional area than the introduction passage and is inserted into the introduction passage through the engagement hole to form an annular slot between the introduction passage and the insertion portion. A lower member including an engaging portion including a tapered portion that increases in cross-sectional area as it is coupled and engages with the engaging hole in a downward direction; and a base portion on which the engaging portion is placed on the upper surface; ,
Comprising
When the entire taper portion of the lower member is covered with the taper portion of the upper member, a gap is formed between the lower surface of the upper member and the upper surface of the base portion of the lower member. A bearing characterized by that. The bearing according to claim 5 , wherein a screw hole through which a screw for tightening each other is formed in the lower surface of the upper member and the base portion of the lower member. The insertion portion of the lower member is formed so as to form a spherical surface together with the upper surface of the upper member when the upper surface reaches the upper surface opening of the upper member,
Furthermore, the upper surface of the said upper member and the upper surface of the said insertion part of the said lower member are the bearings of Claim 6 which were given the polishing process after being tightened with the said screw. An upper member having an upper surface opening formed on a spherical upper surface and a lower surface opening formed on a lower surface, the introduction path communicating with the upper surface opening and an air supply port for taking in air from outside, and the introduction An upper member including an engagement hole including a tapered portion that communicates with the path and the lower surface opening and increases in cross-sectional area as it proceeds downward;
A cylindrical insertion portion having a smaller cross-sectional area than the introduction path and forming an annular slot between the introduction path by being inserted into the introduction path through the engagement hole, and the insertion A lower member including an engaging portion including a tapered portion that is coupled to the portion and has a cross-sectional area that increases in a downward direction so as to engage with the engaging hole;
The bearing characterized by comprising. An upper member having an upper surface opening formed on a spherical upper surface and a lower surface opening formed on a lower surface, the introduction path communicating with the upper surface opening and an air supply port for taking in air from outside, and the introduction Producing an upper member including an engagement hole including a tapered portion that communicates with the path and the lower surface opening and increases in cross-sectional area as it progresses downward;
A cylindrical insertion portion that has a smaller cross-sectional area than the introduction passage and is inserted into the introduction passage through the engagement hole to form an annular slot between the introduction passage and the insertion portion. An engagement portion including a tapered portion that is coupled and that has a cross-sectional area that increases in a downward direction so as to engage with the engagement hole, and the entire taper portion is a taper portion of the engagement hole of the upper member. Manufacturing a lower member including an engagement portion having a gap forming portion extending from the engagement hole when covered with a base portion, and a base portion on which the engagement portion is placed on the upper surface;
Combining the upper member and the lower member such that the entire tapered portion of the engaging portion is covered by the tapered portion of the engaging hole;
Tightening the lower surface of the upper member and the base portion of the lower member using screws;
A bearing manufacturing method comprising: The tightening step comprises:
Immersing the upper surface opening of the upper member in water;
Air is supplied to the air supply port of the upper member, and is discharged from the upper surface opening through an annular slot formed between the introduction path of the upper member and the insertion portion of the lower member. Adjusting the tightening of the screw according to the amount of
The bearing manufacturing method of Claim 9 containing these. After said tightening step, the upper surface and the step of performing a polishing process with respect to formed spherical by the upper surface of the insertion portion of the lower member of the upper member further comprises, according to claim 9 or claim 10 Bearing manufacturing method. An upper member having an upper surface opening formed on a spherical upper surface and a lower surface opening formed on a lower surface, the introduction path communicating with the upper surface opening and an air supply port for taking in air from outside, and the introduction Producing an upper member including an engagement hole including a tapered portion that communicates with the path and the lower surface opening and increases in cross-sectional area as it progresses downward;
A cylindrical insertion portion having a smaller cross-sectional area than the introduction path and forming an annular slot between the introduction path by being inserted into the introduction path through the engagement hole, and the insertion A lower member including an engagement portion including a taper portion that is coupled to the portion and has a cross-sectional area that increases in a downward direction so as to engage with the engagement hole;
Combining the upper member and the lower member such that the tapered portion of the engaging portion engages with the tapered portion of the engaging hole;
A bearing manufacturing method comprising:

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