TWI628370B - Hydrostatic cycling and holding devices - Google Patents

Abstract

A static pressure circulation holding device comprises: a sleeve having an oil storage chamber, a bearing including a bearing shell and a linear bushing, a linear motion axis partially embedded in the linear bushing, and a hydraulic oil filled in the oil storage chamber. The bearing housing has a sidewall through hole communicating with the oil reservoir. The linear bushing has a plurality of grooves formed in the inner wall of the linear bushing and a plurality of radial oil holes communicating with the side wall through holes, each groove having a plurality of groove turning points that are axially open toward the two ends of the linear bushing, respectively. The hydraulic oil forms a pressure oil film between the linear bushing and the linear motion axis through the radial oil hole. When the linear motion axis moves linearly along the axial direction of the linear bushing, the pressure oil film forms a plurality of oil tip points that hold the linear motion axis at the groove turning point toward the linear motion direction.

Description

Static pressure circulation holding device

The present invention relates to a hydraulic holding device applied to high-precision machine equipment, and in particular to a static pressure circulating holding device having a dynamic pressure effect.

With the trend of integrating various functional circuits into a single electronic device, the size of components and substrates of various functional circuits is gradually reduced to less than a millimeter, and the manufacturing of reduced-sized components or substrates requires not only sub-micron tolerance accuracy. It also takes a long time (hours to tens of hours) to maintain the stability and accuracy of the processing action to ensure the yield of a large number of products in a continuous process.

High-precision machines require precise motion mechanisms and positioning control, while the key to precise motion mechanisms and positioning control include high rigidity, low friction, vibration suppression, and constant temperature control. The bearing is a member that supports a rotating axle or a linear motion shaft to withstand the load acting on the shaft and maintain the center position of the shaft. Various studies have indicated that it has high rigidity, high load, high damping, Hydraulic bearings with low friction and long life are the key technologies for developing high-precision mechanical equipment.

According to the way of forming hydraulic pressure, hydraulic bearings can be classified into Hydrodynamic, Hydrostatic and Squeeze-film. The dynamic pressure type bearing uses the relative movement of the contact surface and the viscosity of the fluid, and pulls the fluid into the fine groove on the contact surface to form a bearing oil film, which is usually applied to a small rotating mechanism (for example, a cooling fan). The hydrostatic bearing uses a high-pressure fluid supply system. The external system introduces the pressurized fluid into the gap between the bearing and the shaft through the throttling device to form a bearing oil film, which is usually applied to large-scale precision machine equipment. The squeeze film type bearing utilizes the vibration of the moving shaft in the vertical direction and the viscosity of the fluid, so that the fluid in the gap between the moving shaft and the bearing is not discharged to form the bearing oil film.

Fig. 1A is a schematic cross-sectional view showing a conventional fan using a dynamic pressure bearing. As shown in FIG. 1A, the fan 1 includes a dynamic pressure bearing 10, a bottom plate 11, a fixing base 12, a blade 13, a rotor 14, a stator 15, and a rotating shaft 16. The dynamic pressure bearing 10 is mounted on the fixed seat 12 on the bottom plate 11. The rotating shaft 16 is disposed on the dynamic pressure bearing 12. The fan blade 13 is mounted on the rotating shaft 16 to expose one end of the dynamic pressure bearing 10. The rotor 14 is mounted on the inner side of the blade 13. The stator 15 is fixed on opposite sides of the dynamic pressure bearing 10, and the rotor 14 and the stator 15 can generate mutually exclusive magnetic fields to drive the blades 13 to rotate.

Fig. 1B is a cross-sectional view showing the dynamic pressure bearing of Fig. 1A. As shown in FIG. 1B, the dynamic pressure bearing 10 includes a body 101, an oil guiding groove 102, a fixing portion 103, an oil storage chamber 104, and a bottom cover 105. The rotating shaft 16 is disposed in the rotating shaft hole 1011 of the body 101. A two-way human-shaped oil guiding groove 102 is formed on the inner wall of the rotating shaft hole 1011. The fixing portion 103 is integrally connected to the bottom end of the body 101 and is fixed to the fixing base 12. The oil reservoir 104 communicates with the bottom end of the shaft hole 1011. The bottom cover 105 is closed to one side opening of the oil storage chamber 104. The oil storage chamber 104 is filled with lubricating grease (not shown). When the rotating shaft 16 rotates and pulls the lubricating grease into the gap between the rotating shaft 16 and the inner wall of the rotating shaft hole 1011, the oil guiding groove 102 guides the lubricating grease to flow on the surface of the rotating shaft 16. A pressure oil film is formed between the inner wall of the shaft hole 1011 and the inner wall of the shaft hole 1011 for supporting the rotating shaft 16 not contacting the inner wall of the shaft hole 1011, thereby reducing the running wear of the shaft 16 and the body 101.

The main purpose of the above-mentioned dynamic pressure bearing design of the two-way human-shaped oil guiding groove is to guide the lubricating grease to form a pressure oil film in accordance with different rotation directions of the rotating shaft (shun or counterclockwise direction), however, if the rotating shaft drives the centrifugal force of the lubricating grease to be greater than the viscous force The lubricating grease will be broken toward the human-shaped groove opposite to the rotating direction; if the centrifugal force of the lubricating oil is less than the viscous force, the lubricating grease cannot be uniformly distributed in the same human-shaped groove as the rotating direction, and the uneven pressure oil film may cause The vibration of the shaft is even worn, so the two-way human groove of the rotating bearing cannot actually form an effective pressure oil film.

The design of hydrostatic bearings needs to consider the bearing capacity, liquid flow, static stiffness, dynamic rigidity, damping, heat dissipation and other properties. The optimal conditions for hydrostatic bearings are extremely sensitive to the configuration of the bearings. The performance often affects each other, even the opposite. For example, the rigidity and damping of the bearing are completely opposite. At present, the prior art can only optimize the single performance of the hydrostatic bearing, and cannot be optimized at the same time. Several properties.

Therefore, how to solve the above problems and use hydraulic technology to manufacture mechanical equipment meeting high-precision process requirements is the main purpose of developing the present invention.

To achieve the above object, the present invention provides a static pressure circulation holding device comprising: a sleeve, a bearing, a linear motion axis, and a hydraulic oil. The sleeve has an oil storage chamber. The bearing comprises: a bearing shell disposed in the oil storage chamber and a linear bushing embedded in the bearing shell, wherein the bearing shell has a sidewall through hole communicating with the oil storage chamber, and the linear bushing has a plurality of grooves formed on the inner wall of the linear bushing and located a plurality of radial oil holes between the plurality of grooves, each groove having a plurality of groove turning points respectively opening axially toward the two ends of the linear bushing, the radial oil holes communicating with the side wall through holes. The linear motion axis is partially embedded in the linear bushing through the axial opening of the linear bushing. The hydraulic oil is filled in the oil storage chamber and forms a pressure oil film between the linear bushing and the linear motion axis through the sidewall through hole and the radial oil hole, and when the linear motion axis linearly moves along the axial direction of the linear bushing, The pressure oil film forms a plurality of oil tip points that hold the axis of the linear motion at each groove turning point toward the linear motion direction.

In one embodiment, the sleeve has a shroud that connects the oil storage chamber, and the shroud has a plurality of heat dissipation holes.

In one embodiment, the oil storage chamber has a circulation hole connected to the hydraulic oil circulation device for injecting or discharging the hydraulic oil.

In one embodiment, the radial oil hole surrounds a central portion of the inner wall of the linear bushing, and the groove surrounds the inner wall of the linear bushing on both sides of the radial oil hole.

In one embodiment, the groove and the radial oil hole alternately surround the inner wall of the linear bushing.

In an embodiment, the angle between the groove turning points is less than 90 degrees.

In one embodiment, each of the grooves is a continuous W-shaped groove surrounding the inner wall of the linear bushing.

In one embodiment, the surface of the linear motion axis is formed with a plurality of axis guide grooves.

In one embodiment, the radial thickness of the oil tip point is greater than the radial thickness of the pressure oil film.

In one embodiment, the linear motion axis has a slot for mounting a screw nut and a screw. When the screw is linearly moved by the screw nut to drive the linear motion axis, the screw rotates out or enters the axial direction of the slot. The linear distance differs from the linear motion axis above or from the linear bushing by less than 1 micron.

In the static pressure circulating retainer of the present invention, the bearing comprises a bearing shell and a linear bushing, the bearing shell has a side wall through hole communicating with the sleeve oil storage chamber, and the linear bushing has a plurality of grooves and connecting lines formed on the inner wall of the linear bushing a plurality of radial oil holes of the sidewall through hole, each groove has a plurality of groove turning points respectively opening axially toward the two ends of the linear bushing, and the hydraulic oil stored in the oil reservoir of the sleeve can be linearly lined through the radial oil hole A pressure oil film is formed between the sleeve and the linear motion axis. When the linear motion axis moves linearly along the axial direction of the linear bushing, the pressure oil film forms a high-pressure-holding linear motion axis at each groove turning point toward the linear motion direction. A plurality of oil tip points provide good support for the linear motion axis, suppress vibration damping, heat dissipation and lubrication. In addition, since the static pressure circulation holding device of the present invention can achieve the accuracy of sub-micron tolerances, the static pressure circulation holding device of the present invention can be used as a calibration device for a distance measuring instrument, in addition to being applicable to a high-precision machine tool.

The embodiments of the present invention will be described in detail below with reference to the drawings and the elements of the present invention, and the present invention may be practiced by those of ordinary skill in the art.

2A is a perspective view showing a static pressure circulation holding device according to an embodiment of the present invention, and FIG. 2B is a schematic axial sectional view showing the static pressure circulating holding device shown in FIG. 2A. As shown in FIGS. 2A and 2B, the static pressure circulation holding device 2 includes a sleeve 21, a bearing 22, a linear motion axis 23, and hydraulic oil (not shown).

In this embodiment, the sleeve 21 has an oil storage chamber 211, a shroud 212 and a sleeve flange 213. The shroud 212 is connected to one end opening of the oil storage chamber 211, and the sleeve flange 213 is disposed at the oil storage chamber 211. Open at one end. The shield 212 has a plurality of heat dissipation holes 2121 for assisting the heat dissipation of the linear motion axis 23. The oil reservoir 211 has a circulation hole 2111 connected to a hydraulic oil circulation device (not shown) for injecting or discharging hydraulic oil.

The bearing 22 includes a bearing housing 221, a linear bushing 222, and a bearing flange 223. The linear bushing 222 is inserted into the bearing housing 221 from one end of the bearing housing 221, and the bearing flange 223 is disposed on the other end opening of the bearing housing 221. The outer diameter of the bearing housing 221 is smaller than the inner diameter of the oil reservoir 211, and the bearing housing 221 can be inserted into the oil storage chamber 211 from the opening of the sleeve flange 213 end. The sleeve flange 213 has a corresponding locking hole with the bearing flange 223 to fix the bearing 22 to the oil reservoir 211 by means of a screw lock. It should be noted that in the static pressure circulation holding device of the present invention, the manner in which the bearing is disposed in the oil storage chamber is not limited to the use of the sleeve flange 213 and the bearing flange 223.

The bearing housing 221 has four side wall through holes 2211, and the adjacent two side wall through holes 2211 are spaced apart from each other by 90 degrees (1/4 circle), and the side wall through holes 2211 respectively communicate with the oil storage chamber 211, but the number of the side wall through holes 2211 Not limited to four, for example: three, six, eight, etc. The linear bushing 222 has a plurality of grooves 2222 formed on the inner wall 2221 of the linear bushing and a plurality of radial oil holes 2223 between the grooves 2222. A portion of the radial oil holes 2223 communicate with the side wall through holes 2211, and the grooves 2222 There are a plurality of groove turning points 2222a that are axially open toward the two ends of the linear bushing 222, respectively, and the angle of each groove turning point 2222a is less than 90 degrees.

In the present embodiment, the inner diameter of the central portion of the side wall through hole 2211 of the bearing housing 221 is larger than the inner diameter of the two sides, and the hydraulic oil can be filled in the central portion of the bearing housing 221 through the four side wall through holes 2211. The inner diameter of the central portion of the inner wall 2221 of the linear bushing is larger than the inner diameter of the two sides, the radial oil hole 2223 surrounds the central portion of the inner wall 2221 of the linear bushing, and the hydraulic oil can be filled in the linear bushing 222 through the radial oil hole 2223. Central area. The groove 2222 is formed on the linear bushing inner wall 2221 on both sides of the radial oil hole 2223, and the groove 2222 on each side is a continuous W-shaped groove surrounding the inner wall 2221 of the linear bushing and spaced apart from each other by the groove 2222. The width and depth dimensions are, for example, 0.1 to several millimeters (mm).

In other embodiments of the invention, the inner wall of the linear bushing may form a different groove design. As shown in FIG. 3, a perspective view of a linear bushing according to an embodiment of the present invention, a plurality of continuous W-shaped grooves 3222 of the linear bushing 322 and a plurality of radial oil holes 3223 alternately surround the inner wall 3221 of the linear bushing, each continuous The W-shaped grooves 3222 are the same size and have a plurality of groove turning points 3222a that are axially open toward the two sides.

As shown in FIG. 4, a perspective view of a linear bushing according to another embodiment of the present invention, a plurality of radial oil holes 4223 of the linear bushing 422 surround a central portion of the inner wall 4221 of the linear bushing, and a plurality of continuous W-shaped grooves 4222 The linear bushing inner walls 4221 of the two sides of the radial oil holes 4223 are arranged in different sizes and in sequence, and each of the continuous W-shaped grooves 4222 has a plurality of groove turning points 4222a axially open toward the two sides.

As shown in FIG. 5, a perspective view of a linear bushing according to still another embodiment of the present invention, a plurality of radial oil holes 5223 of the linear bushing 522 surround a central portion of the inner wall 5221 of the linear bushing, and a plurality of continuous circular grooves 52222 surround The linear bushing inner wall 5221 on both sides of the radial oil hole 5223 has different sizes of the continuous crotch grooves 5222 on each side, and sequentially arranges the linear bushing inner wall 5221 on both sides of the radial oil hole 5223, and the sides are continuous. The shaped groove 5222 has a plurality of groove turning points 5222a that open axially toward the same side.

Referring again to FIGS. 2A and 2B, the linear motion axis 23 is partially embedded in the linear bushing 222 through the axial opening of the shroud 212 of the sleeve 21 and the linear bushing 222 (in the direction indicated by the arrow). In the present embodiment, the surface of the linear motion axis 23 is formed with a plurality of axis guide grooves 231 corresponding to the groove turning points 2222a. Further, the linear motion axis 23 further has a screw nut and a screw (not shown). The first slot 232 and the second slot 233 for mounting a tool (for example, a punch of a punch, not shown).

The outer diameter of the linear motion axis 23 is slightly smaller than the inner diameter of the linear bushing 222, and the gap therebetween is, for example, 0.01 to 0.1 mm. Since the hydraulic oil of the oil storage chamber 211 has a certain hydraulic pressure, and the gap between the linear bushing 222 and the linear motion axis 23 can generate capillary action, the hydraulic oil can pass through the sidewall through hole 2211 and the radial oil hole 2223 to the linear bushing 222. A pressure oil film (not shown) is formed between the linear motion axis 23 and the linear motion axis 23 . In the present invention, the hydraulic oil can be used as a general bearing hydraulic oil, and is not particularly limited. The pressure oil film formed by the hydraulic oil can provide the support tension and lubrication required for the linear motion axis 23 to perform linear motion, and the linear motion axis 23 does not. Direct contact with the inner wall 2221 of the linear bushing can greatly reduce the frictional force of the linear motion axis 23 and the frictional heat generated by the linear motion.

The static pressure circulation holding device of the present invention can manufacture mechanical equipment that meets the requirements of high precision processes. Fig. 6 is a schematic cross-sectional view showing a machine tool to which the static pressure circulation holding device of the present invention is applied. As shown in Fig. 6, the machine tool 6 includes a static pressure circulation holding device 60, a base 61, a servo motor 62, a screw 63, and a hydraulic oil circulation device 64. The static pressure circulation holding device 60 is fixed to the base 61. The head of the screw 63 is coupled to the rotating shaft of the servo motor 62, and the threaded portion of the screw 63 is provided to the static pressure circulation holding device 60. The hydraulic oil circulation device 64 communicates with the static pressure circulation holding device 60 for injecting or discharging the pressurized hydraulic oil 605 into the static pressure circulation holding device 60.

The static pressure circulation holding device 60 includes a sleeve 601, a bearing 602, a linear motion axis 603, a screw nut 604, and a hydraulic oil 605. The sleeve 601 is disposed above the base 61, and the bearing 602 is fitted into the oil reservoir 6011 of the sleeve 601 from below the base 61. The sleeve flange 6013, the base 61, and the bearing flange 6023 are provided with corresponding screw holes, and the sleeve flange 6013 and the bearing flange 6023 are respectively screwed to the base 61 by the two sides of the base 61. The linear motion axis 603 is partially embedded in the bearing 602 through the shroud 6012 of the sleeve 601. The hydraulic oil 605 is stored in the oil storage chamber 6011.

The bearing 602 includes a bearing housing 6021 and a linear bushing 6022. The bearing housing 6021 has four side wall through holes 60211. The adjacent two side wall through holes 60211 are spaced apart from each other by 90 degrees (1/4 circle); the linear bushing 6022 has a formation. a continuous W-shaped groove 60222 of the linear bushing inner wall 60221 and a radial oil hole 60223 communicating with the sidewall through hole 60211, each of the continuous W-shaped grooves 60222 having a plurality of axial openings respectively facing the two ends of the linear bushing 6022 Trench turning point 60222a (as shown in Figure 7B). The linear motion axis 603 has a shaft guiding groove 6031, a first groove 6032, and a second groove 6033. The axis guiding groove 6031 corresponds to a groove turning point 60222a arranged in the axial direction. A screw nut 604 (for example, a ball screw nut) and a tool (for example, a punch, not shown) are respectively locked to the first slit 6032 and the second slit 6033 of the linear motion axis 603. The servo motor 62 drives the screw 63 to rotate or enter the first slot 6032 of the linear motion axis 603. The screw nut 604 can convert the torque of the screw 63 into a linear thrust to drive the linear motion axis 603 to perform linear motion for linear motion. The shaft 603 drives the tool to extend or retract into the bearing 602. The hydraulic oil 605 forms a pressure oil film supporting the linear motion axis 603 through the side wall through hole 60211 and the radial oil hole 60223.

Fig. 7A is a schematic cross-sectional view showing the vertical downward movement of the hydrostatic circulation holding device shown in Fig. 6, and Fig. 7B is a cross-sectional view showing the bearing in Fig. 7A. As shown in FIG. 7A, during the vertical downward movement of the linear motion axis 603 in the axial direction (as indicated by the hollow arrow), the pressure oil film 6051 flows along the linear motion axis 603, and flows. The portion of the hydraulic oil 605 pushed by the pressure oil film 6051 in the central portion of the linear bushing 6022 flows into the oil storage chamber 6011 through the radial oil hole 60223 and the side wall through hole 60211; since the oil storage chamber 6011 has a certain pressure, it is filled in the oil storage chamber 6011. The hydraulic oil 605 is squeezed by the inflowing hydraulic oil 605 and then flows through the radial oil hole 60223 and the sidewall through hole 60011 to flow between the linear bushing 6022 and the linear motion axis 603 to form a pressure oil film 6051. The circulating hydraulic oil 605 flows. The pressure oil film 6051 can provide excellent lubricity and a very low friction coefficient of the linear motion axis 603, and can also transfer the friction heat generated by the linear motion to the heat dissipation holes of the oil storage chamber 6011 and the shroud 6012 for heat dissipation.

As shown in FIG. 7B, in the process in which the pressure oil film 6051 flows downward, the pressure oil film 6051 filled in the V-shaped sides of each of the W-shaped grooves 60222 is driven to be pressed toward the groove turning point 60222a in the linear motion direction to have a shape. The high hydraulic oil tip point 6052, the oil tip point 6052 radially surrounding the linear motion axis 603, uniformly applies radial pressure to hold the linear motion axis 603 to the vertical axis. In addition, since the radial thickness of the oil tip point 6052 is slightly larger than the radial thickness of the pressure oil film 6051, and the axis guiding groove 6031 of the linear motion axis 603 corresponds to a portion of the axially arranged groove turning point 60222a, the axis guide groove is protruded. The oil tip point 6052 of 6031 can further provide a linear motion axis 603 to suppress vibration or rotational damping.

Fig. 8A is a schematic cross-sectional view showing the vertical upward movement of the static pressure circulation holding device shown in Fig. 6, and Fig. 8B is a schematic sectional view showing the bearing in Fig. 8A. As shown in FIG. 8A, during the vertical upward movement of the linear motion axis 603 in the axial direction (as indicated by the hollow arrow), the pressure oil film 6051 flows along the linear motion axis 603, and the flow pressure The oil film 6051 pushes a part of the hydraulic oil 605 in the central portion of the linear bushing 6022 into the oil storage chamber 6011 through the radial oil hole 60223 and the side wall through hole 60211; the hydraulic pressure filled in the oil storage chamber 6011 due to the oil storage chamber 6011 having a certain pressure The oil 605 is squeezed by the inflowing hydraulic oil 605 and then flows through the radial oil hole 60223 and the sidewall through hole 60211 to flow between the linear bushing 6022 and the linear motion axis 603 to form a pressure oil film 6051, and the circulating hydraulic oil 605 and The pressure oil film 6051 can provide excellent lubricity of the linear motion axis 603 and an extremely low friction coefficient, and can also transfer the friction heat generated by the linear motion to the heat dissipation holes of the oil storage chamber 6011 and the shroud 6012 for heat dissipation.

As shown in FIG. 8B, in the process of the upward flow of the pressure oil film 6051, the pressure oil film 6051 filled in the two sides of the W-shaped groove 60222 is driven to be pressed to form a groove turning point 60222a in the linear motion direction. The hydraulic oil tip point 6052, since the radial thickness of the oil tip point 6052 is slightly larger than the radial thickness of the pressure oil film 6051, the oil tip point 6052 radially surrounding the linear motion axis 603 can uniformly apply radial pressure to the linear motion axis. The heart 603 is held on the vertical axis. In addition, the axis guiding groove 6031 of the linear motion axis 603 corresponds to a partially axially arranged groove turning point 60222a, and the oil tip point 6052 protruding into the axis guiding groove 6031 can further provide the linear motion axis 603 to suppress vibration or rotational damping.

After the actual test of the mounting punch, the linear motion axis 603 performs vertical punching of the workpiece for at least a period of time (for example, several hours to several tens of hours), and the axial distance of the screw 63 rotated or inserted into the first slot 6032 is The linear motion axis 603 extends or retracts into the linear bushing 6022 by a distance of less than 1 micron, even up to a tolerance of less than 0.1 micron, meeting the micron tolerance requirements of high precision processes.

In summary, in the static pressure circulating retainer of the present invention, the bearing comprises a bearing shell and a linear bushing, the bearing shell has a sidewall through hole communicating with the sleeve oil storage chamber, and the linear bushing has a hollow bushing formed on the inner wall of the linear bushing. a plurality of grooves and a plurality of radial oil holes communicating with the side wall through holes, each groove having a plurality of groove turning points respectively opening axially toward the two ends of the linear bushing, and the hydraulic oil stored in the oil reservoir of the sleeve can pass the radial oil The hole forms a pressure oil film between the linear bushing and the linear motion axis. When the linear motion axis moves linearly along the axial direction of the linear bushing, the pressure oil film forms a high pressure holding straight line at the groove turning point toward the linear motion direction. The plurality of oil tip points of the motion axis provide good support for the linear motion axis, suppress vibration damping, heat dissipation and lubrication. In addition, since the static pressure circulation holding device of the present invention can achieve the accuracy of sub-micron tolerances, the static pressure circulation holding device of the present invention can be used as a calibration device for a distance measuring instrument, in addition to being applicable to a high-precision machine tool.

The above-described embodiments are merely illustrative of the principles of the invention and its effects, and are not intended to limit the invention. Modifications and variations of the above-described embodiments can be made by those skilled in the art without departing from the spirit and scope of the invention. Therefore, all equivalent modifications and changes may be made without departing from the spirit and scope of the invention as disclosed in the appended claims.

1 of the fan base 10 11 12 dynamic pressure bearing holder 14 stator 16 rotor 15 rotating shaft 102 is turned groove 101 of the body 104 oil reservoir chamber 105 shaft hole 103 of the bottom cover 1011 fixed blade portion 13, 60 remains static pressure cycle Set 6 Machine tool 21, 601 Sleeve 22, 602 Bearing 23, 603 Linear motion axis 61 Base 62 Servo motor 63 Screw 64 Hydraulic oil circulation device 211, 6011 Oil storage chamber 212, 6012 Shield 213, 6013 Sleeve convex Edge 2111 circulation hole 2121 heat dissipation hole 221, 6021 bearing housing 222, 322, 422, 522, 6022 Linear bushing 223, 6023 bearing flange 231, 6031 shaft guide groove 232, 6032 first slot 233, 6033 second slot 604 screw nut 605 hydraulic oil 2211, 60211 sidewall through hole 2221, 3221, 4221, 5221, 60221 Linear bushing inner wall 2222, 3222, 4222, 5222, 60222 Groove 2223, 3223, 4223, 5223, 60223 Radial oil hole 6051 Pressure oil film 6052 Oil tip point 2222a, 3222a, 4222a, 5222a, 60222a Groove turning point

1A is a cross-sectional view of a conventional fan using a dynamic pressure bearing, FIG. 1B is a cross-sectional view of the dynamic pressure bearing of FIG. 1A; FIG. 2A is a static pressure circulating holding device of an embodiment of the present invention; 3B is a schematic axial cross-sectional view of the static pressure circulation holding device shown in FIG. 2A; FIG. 3 is a perspective view of a linear bushing according to an embodiment of the present invention; 3 is a perspective view of a linear bushing according to still another embodiment of the present invention; and FIG. 6 is a schematic cross-sectional view of a power tool using the static pressure circulating holding device of the present invention; Figure 7 is a schematic cross-sectional view of the static pressure cycle holding device shown in Figure 6 for vertical downward movement, Figure 7B is a schematic cross-sectional view of the bearing in Figure 7A; and Figure 8A is the static pressure cycle shown in Figure 6 A schematic cross-sectional view of the apparatus for vertical upward movement, and FIG. 8B is a schematic cross-sectional view of the bearing of FIG. 8A.

Claims (9)

A static pressure circulation holding device comprises: a sleeve having an oil storage chamber; and a bearing comprising: a bearing shell disposed in the oil storage chamber and a linear bushing embedded in the bearing shell, wherein the bearing shell has a connection with the oil storage chamber a sidewall via having a plurality of trenches formed in an inner wall of the linear bushing and a plurality of radial oil holes between the trenches, each of the trenches having a side facing the linear bushing a plurality of groove turning points axially opening, the radial oil holes communicating with the side wall through holes; a linear motion axis partially embedded in the linear bushing through an axial opening of the linear bushing; and hydraulic oil filled in The oil storage chamber forms a pressure oil film between the linear bushing and the linear motion axis through the sidewall through hole and the radial oil holes, and the linear motion axis is along the axial direction of the linear bushing During linear motion, the pressure oil film forms a plurality of oil tip points for holding the linear motion axis at the groove turning points toward the linear motion direction, wherein the oil storage chamber has a circulation hole connecting the hydraulic oil circulation device for injection Or row The hydraulic oil. The static pressure circulation holding device of claim 1, wherein the sleeve has a shroud connected to the oil storage chamber, the shroud having a plurality of heat dissipation holes. The static pressure circulation holding device according to claim 1, wherein the radial oil holes surround a central portion of the inner wall of the linear bushing, and the grooves surround the linear lining on both sides of the radial oil holes. Set of inner walls. The static pressure circulation holding device of claim 1, wherein the grooves and the radial oil holes alternate around the inner wall of the linear bushing. The static pressure circulation holding device according to claim 1, wherein the groove turning point has an included angle of less than 90 degrees. The static pressure circulation holding device of claim 1, wherein each of the grooves is a continuous W-shaped groove surrounding an inner wall of the linear bushing. The static pressure circulation holding device according to claim 1, wherein the surface of the linear motion axis is formed with a plurality of axis guide grooves. The static pressure circulation holding device of claim 1, wherein the oil tip point has a radial thickness greater than a radial thickness of the pressure oil film. The static pressure circulation holding device according to claim 1, wherein the linear motion axis has a slot for mounting a screw nut and a screw, and the screw drives the linear motion axis through the screw nut to perform the straight line When moving, the axial distance of the screw rotating or moving into the slot is less than 1 micrometer from the distance of the linear motion axis extending or retracting into the linear bushing.