A dynamic pressure bearing for actively controlling dynamic pressure

Abstract

The present invention discloses a hydrodynamic bearing for actively controlling dynamic pressure, which relates to the technical field of fluid hydrodynamic bearings, including a bearing and a journal matched with the bearing, wherein the bearing includes a body, an elastic film, a pressure plate, a thrust hemisphere, a piezoelectric ceramic driver, a bolt and a baffle; the elastic film is fixed on the inner wall of the body. A plurality of cylindrical cavities are opened on the inner wall of the body on the side matching with the journal, and a piezoelectric ceramic driver is arranged in the cylindrical cavity; the piezoelectric ceramic driver is connected to the film arc surface by arranging a thrust hemisphere; the beneficial effect of the present invention is that the thrust hemisphere pushes the film arc surface to move radially through the extension and contraction of the piezoelectric ceramic driver, thereby realizing active control of the size of the wedge gap A and the wedge gap B, thereby controlling the size of the dynamic pressure, and realizing control of the oil film force, which can be used in applications such as suppressing the journal vibration and actively controlling the axis trajectory.

Description

Technical Field

[0001] The invention relates to the technical field of fluid dynamic pressure bearings, in particular to a dynamic pressure bearing for actively controlling dynamic pressure. Background Art

[0002] The sliding bearings of the main shaft can be divided into two categories according to the way they generate oil film pressure: hydrodynamic bearings and static pressure bearings. When the hydrodynamic bearing is in working state, it is liquid hydrodynamic lubrication, and the friction only occurs between the molecules of the lubricant, so the friction resistance is very small, and the sliding surface is not easy to wear, which is an ideal working state. The hydrodynamic bearing runs smoothly, has a simple structure, low noise, and has greater rigidity and overload resistance.

[0003] Hydrodynamic bearings have load-bearing capacity by forming an oil film due to the rotation of the shaft. The load-bearing capacity is proportional to the sliding speed. Hydrodynamic bearings are divided into hydrodynamic radial bearings and hydrodynamic thrust bearings. Hydrodynamic radial bearings are further divided into single oil wedge and multi-oil wedge types; multi-oil wedge hydrodynamic radial bearings have two or more oil wedge bearings around the journal. Before the multi-oil wedge radial bearing bears the load, that is, when the journal center coincides with the bearing geometric center, there is an eccentricity relative to the center of curvature of each section of the bearing surface, and the eccentricity value is equal. The pressure generated in the oil film on each bearing surface is the same, and the force on the journal is balanced. After bearing the load, these eccentricity values ​​increase or decrease, and the oil film pressure on each bearing surface decreases or increases accordingly. The bearing load capacity is the sum of these oil film pressure vectors. The multi-oil wedge bearing has a lower load-bearing capacity than the single oil wedge bearing, but the main bearing bearing surface has an additional oil film pressure, which can improve the stability of the bearing operation.

[0004] The bearing capacity depends on the speed of the journal. The change in speed affects the dynamic pressure and combined force of the oil film, which in turn affects the rotation accuracy of the journal. The dynamic lubrication characteristics of the hydrodynamic bearing are determined by the wedge clearance. The size of the wedge clearance determines the size of the dynamic pressure. Under certain journal speed and lubricating oil viscosity, the smaller the wedge clearance, the greater the dynamic pressure. Therefore, most of the improvements to hydrodynamic bearings on the market are centered around improving the wedge clearance. Accurately determining the optimal wedge clearance is one of the main tasks in designing and manufacturing hydrodynamic bearings.

[0005] The present invention controls the size of the dynamic pressure by actively controlling the size of the wedge gap. The integral of the dynamic pressure is the oil film bearing capacity, which realizes the active control of the oil film bearing capacity, and is mainly used to suppress the vibration of the journal and actively control the axis trajectory. Summary of the invention

[0006] The object of the present invention is to provide a hydrodynamic bearing for actively controlling the dynamic pressure, which is suitable for applications such as journal vibration suppression and active shaft center trajectory control.

[0007] To achieve the above-mentioned purpose, the technical solution of the present invention is a hydrodynamic bearing for actively controlling dynamic pressure, comprising a bearing and a shaft neck matched with the bearing, wherein the bearing comprises a body, an elastic film, a pressure plate, a thrust hemisphere, a piezoelectric ceramic driver, a bolt and a baffle; the elastic film is fixed to the inner wall of the body by at least three pressure plates evenly distributed along the circumferential direction, and at least three film connection positions and film arc surfaces are formed on the elastic film after fixation; at least three cylindrical cavities are arranged alternately and evenly with the pressure plates on the inner wall of the body on the side matching with the shaft neck, and a piezoelectric ceramic driver is arranged in the cylindrical cavity; the piezoelectric ceramic driver is connected to the film arc surface by setting a thrust hemisphere, and a wedge-shaped gap A and a wedge-shaped gap B are formed between the film arc surface of the elastic film and the shaft neck, and the film arc surface is driven to move radially by controlling the elongation or shortening of the piezoelectric ceramic driver, thereby actively controlling the size of the wedge-shaped gap A and the wedge-shaped gap B.

[0008] Furthermore, the wedge-shaped gap A and the wedge-shaped gap B respectively form convergent wedge-shaped gaps when the journal rotates counterclockwise and clockwise, thereby respectively forming dynamic pressures when the journal rotates in two directions.

[0009] Furthermore, a threaded hole A is formed on the outer cylindrical surface of the body at a position corresponding to the cylindrical cavity, and a bolt is arranged in the threaded hole A. The piezoelectric ceramic driver can be replaced by removing the bolt.

[0010] Furthermore, a film through hole is provided at the middle position of the film connecting portion of the elastic film.

[0011] Furthermore, the pressure plate includes a pressure plate arm and two fixed ends. A pressure plate through hole is opened at the center of the pressure plate arm, and a threaded hole B is opened on the fixed end, which is connected to the body by screws.

[0012] Furthermore, the outer cylindrical surface of the body is provided with a main oil supply hole A and a main oil supply hole B, and the main oil supply hole A and the main oil supply hole B are connected with the axial oil supply hole A and the axial oil supply hole B respectively.

[0013] Furthermore, an annular groove is formed on the end surface of the body, and the baffle cooperates with the annular groove and is installed on the end surface of the bearing through the threaded hole C, so that the annular groove forms a closed oil supply path.

[0014] Furthermore, the annular groove is respectively connected with the axial oil supply hole A, the axial oil supply hole B, the axial oil supply hole C, the axial oil supply hole D and the axial oil supply hole E; the axial oil supply hole A, the axial oil supply hole B, the axial oil supply hole C, the axial oil supply hole D and the axial oil supply hole E are further respectively connected with the radial oil supply hole A, the radial oil supply hole B, the radial oil supply hole C, the radial oil supply hole D and the radial oil supply hole E; the radial oil supply hole A, the radial oil supply hole B, the radial oil supply hole C, the radial oil supply hole D and the radial oil supply hole E are further respectively connected with the film through hole and the pressure plate through hole.

[0015] A hydrodynamic bearing for actively controlling dynamic pressure is manufactured using the technical solution of the present invention, and its beneficial effects are as follows: (1) Compared with conventional liquid hydrodynamic bearings, the hydrodynamic bearing for actively controlling dynamic pressure of the present invention acts on the thrust hemisphere through the extension and contraction of the piezoelectric ceramic driver, pushing the film arc surface to move radially, and realizing active control of the size of the wedge gap A and the wedge gap B, thereby controlling the size of the dynamic pressure. The product of the dynamic pressure and the area is the oil film force, which also realizes the control of the oil film force, and can be used in applications such as suppressing the vibration of the journal and actively controlling the axis trajectory. (2) In conventional bearings, the bearing capacity of the bearing depends on the rotation speed of the journal. The change in speed affects the dynamic pressure and the resultant force of the oil film, which also affects the rotation accuracy of the journal. Actively controlling the size of the wedge gap can actively control the dynamic pressure and the resultant force of the oil film, and improve the rotation accuracy of the journal. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic structural diagram of a hydrodynamic bearing for actively controlling dynamic pressure of the present invention;

[0017] Figure 2 A transverse cross-sectional view of a hydrodynamic bearing for actively controlling dynamic pressure according to the present invention;

[0018] Figure 3 An axial view of a hydrodynamic bearing for actively controlling dynamic pressure according to the present invention;

[0019] Figure 4 It is a structural schematic diagram of the baffle of the present invention;

[0020] Figure 5 It is a structural schematic diagram of the pressing plate of the present invention;

[0021] In the above figures,

[0022] 1 bearing; 11 body; 111 threaded hole A; 112 cylindrical cavity; 113 main oil supply hole A; 114 main oil supply hole B; 115 axial oil supply hole A; 116 axial oil supply hole B; 117 axial oil supply hole C; 118 axial oil supply hole D; 119 axial oil supply hole E; 1110 radial oil supply hole A; 1111 radial oil supply hole B; 1112 radial oil supply hole C; 1113 radial oil supply hole D; 1114 radial oil supply hole E; 1115 annular groove;

[0023] 12 elastic film; 121 film through hole; 122 film connection position; 123 film arc surface; 124 wedge-shaped gap A; 125 wedge-shaped gap B;

[0024] 13 pressing plate; 131 pressing plate arm; 132 fixing end; 133 pressing plate through hole; 134 threaded hole B;

[0025] 14 piezoelectric ceramic driver; 15 thrust hemisphere; 16 bolt;

[0026] 17 baffle; 171 threaded hole C; 2 journal. DETAILED DESCRIPTION

[0027] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation methods, structures, features and effects of the present invention are described in detail below in conjunction with the accompanying drawings and preferred embodiments:

[0028] A hydrodynamic bearing that actively controls the dynamic pressure, such as Figures 1 to 5 As shown, it includes a bearing 1 and a journal 2 matched with the bearing. The bearing includes a body 11, an elastic film 12, a pressure plate 13, a piezoelectric ceramic driver 14, a thrust hemisphere 15, a bolt 16 and a baffle 17, wherein the elastic film 12 is fixed to the inner wall of the body 11 by five pressure plates 13 evenly distributed along the circumferential direction. After being fixed, five film connection positions 122 and five film arc surfaces 123 are formed on the elastic film 12; the inner wall of the body 11 is provided with five holes 122 and 123 alternately and evenly distributed with the pressure plates 13 on the side matched with the journal 2. A cylindrical cavity 112 is evenly arranged, and a piezoelectric ceramic driver 14 is arranged in the cylindrical cavity 112; the piezoelectric ceramic driver 14 is connected to the film arc surface 123 by arranging a thrust hemisphere 15; a wedge gap A124 and a wedge gap B125 are formed between the film arc surface 123 of the elastic film 12 and the shaft neck 2, and the film arc surface 123 is driven to move radially by controlling the elongation or shortening of the piezoelectric ceramic driver 14, so that the sizes of the wedge gap A124 and the wedge gap B125 can be actively controlled.

[0029] The wedge-shaped gap A124 and the wedge-shaped gap B125 respectively form convergent wedge-shaped gaps when the journal rotates counterclockwise and clockwise, thereby respectively forming dynamic pressures when the journal rotates in two directions.

[0030] A threaded hole A111 is formed on the outer cylindrical surface of the body 11 at a position corresponding to the cylindrical cavity 112 . A bolt 16 is disposed in the threaded hole A111 . The piezoelectric ceramic driver 14 can be replaced by removing the bolt 16 .

[0031] A film through hole 121 is formed in the middle of the film connecting portion 122 of the elastic film 12 .

[0032] The pressure plate 13 includes a pressure plate arm 131 and two fixed ends 132 . A pressure plate through hole 133 is formed at the center of the pressure plate arm 131 . A threaded hole B134 is formed on the fixed ends 132 . The pressure plate 13 is connected to the body 11 by screws.

[0033] The outer cylindrical surface of the body 11 is provided with a main oil supply hole A113 and a main oil supply hole B114, which are connected to the axial oil supply hole A115 and the axial oil supply hole B116 respectively.

[0034] An annular groove 1115 is formed on the end surface of the body 11, and the baffle 17 cooperates with the annular groove 1115 and is installed on the end surface of the bearing through the threaded hole C171, so that the annular groove 1115 forms a closed oil supply path.

[0035] The annular groove 1115 is respectively connected with the axial oil supply hole A115, the axial oil supply hole B116, the axial oil supply hole C117, the axial oil supply hole D118 and the axial oil supply hole E119; the axial oil supply hole A115, the axial oil supply hole B116, the axial oil supply hole C117, the axial oil supply hole D118 and the axial oil supply hole E119 are further respectively connected with the radial oil supply hole A1110, the radial oil supply hole B1111, the radial oil supply hole C1112, the radial oil supply hole D1113 and the radial oil supply hole E1114; the radial oil supply hole A1110, the radial oil supply hole B1111, the radial oil supply hole C1112, the radial oil supply hole D1113 and the radial oil supply hole E1114 are further respectively connected with the film through hole 121 and the pressure plate through hole 133.

[0036] In the hydrodynamic bearing for actively controlling the dynamic pressure of the present invention, the lubricating oil circuit is as follows: the lubricating oil enters from the main oil supply hole A113 and the main oil supply hole B114, flows through the axial oil supply hole A115 and the axial oil supply hole B116 into the annular groove 1115, flows from the annular groove 1115 to the axial oil supply hole C117, the axial oil supply hole D118 and the axial oil supply hole E119, and then flows to the radial oil supply hole A1110, the radial oil supply hole B1111, the radial oil supply hole C1112, the radial oil supply hole D1113 and the radial oil supply hole E1114, and then flows through the pressure plate through hole 133 and the film through hole 121 to reach the bearing gap. Driven by the rotation of the journal, it reaches the wedge gap A124 and the wedge gap B125.

[0037] The hydrodynamic bearing of the present invention that actively controls the dynamic pressure, when working, acts on the thrust hemisphere 15 through the extension and contraction of the piezoelectric ceramic driver 14, pushing the film arc surface 123 to move radially, and realizing active control of the size of the wedge gap A124 and the wedge gap B125. The size of the wedge gap determines the size of the dynamic pressure. Under certain journal rotation speed and lubricating oil viscosity, the smaller the wedge gap, the greater the dynamic pressure. The size of the dynamic pressure is controlled by controlling the size of the wedge gap A124 and the wedge gap B125. The product of the dynamic pressure and the area is the oil film force, which realizes the control of the oil film force, and can be used in applications such as suppressing journal vibration and actively controlling the axis trajectory.

[0038] The present invention is described above with reference to the preferred embodiments, but the protection scope of the present invention is not limited thereto. Various improvements can be made to the embodiments and parts thereof can be replaced with equivalents without departing from the scope of the present invention. As long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way, and any figure mark in the claims should not be regarded as limiting the claims involved. No matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. Therefore, all technical solutions falling within the scope of the claims are within the protection scope of the present invention.

Claims

1. A hydrodynamic bearing for actively controlling dynamic pressure, comprising a bearing (1), characterized in that: It also includes a shaft neck (2) matched with a bearing, wherein the bearing includes a body (11), an elastic film (12), a pressure plate (13), a piezoelectric ceramic driver (14), a thrust hemisphere (15), a bolt (16) and a baffle (17); The elastic film (12) is fixed to the inner wall of the body (11) by at least three pressing plates (13) evenly distributed along the circumferential direction, and after being fixed, at least three film connection positions (122) and three film arc surfaces (123) are formed on the elastic film (12); At least three cylindrical cavities (112) are arranged alternately and evenly with the pressure plate (13) on the inner wall of the body (11) on the side matching the shaft neck (2), and a piezoelectric ceramic driver (14) is arranged in the cylindrical cavity (112); the piezoelectric ceramic driver (14) and the film arc surface (123) are connected by arranging a thrust hemisphere (15); A threaded hole A (111) is formed on the outer cylindrical surface of the body (11) at a position corresponding to the cylindrical cavity (112), and a bolt (16) is arranged in the threaded hole A (111); The pressure plate (13) comprises a pressure plate arm (131) and two fixed ends (132); a pressure plate through hole (133) is provided at the center of the pressure plate arm (131); a threaded hole B (134) is provided on the fixed end (132), and the pressure plate is connected to the body (11) by screws; A wedge-shaped gap A (124) and a wedge-shaped gap B (125) are formed between the film arc surface (123) of the elastic film (12) and the shaft neck (2).

2. A hydrodynamic bearing for actively controlling dynamic pressure according to claim 1, characterized in that: A film through hole (121) is provided at the middle position of the film connection position (122) of the elastic film (12).

3. The hydrodynamic bearing for actively controlling the dynamic pressure according to claim 1, characterized in that: The outer cylindrical surface of the body (11) is provided with a main oil supply hole A (113) and a main oil supply hole B (114), and the main oil supply hole A (113) and the main oil supply hole B (114) are respectively connected with the axial oil supply hole A (115) and the axial oil supply hole B (116).

4. The hydrodynamic bearing for actively controlling the dynamic pressure according to claim 1, characterized in that: An annular groove (1115) is formed on the end surface of the body (11), and the baffle (17) cooperates with the annular groove (1115) and is installed on the end surface of the bearing through a threaded hole C (171).

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