A liquid dynamic bearing

Abstract

The present invention discloses a liquid hydrodynamic bearing, which relates to the technical field of bearings. The liquid hydrodynamic bearing includes a bearing, a shaft neck matched with the bearing, and the bearing includes a body, and also includes: at least three pressure plates, the pressure plates are evenly spaced and arranged on the inner cylindrical surface of the body; an elastic film, the elastic film is surrounded by the pressure plate and arranged on the inner cylindrical surface of the body; a cylindrical cavity, the cylindrical cavity is arranged between two adjacent pressure plates on the inner cylindrical surface of the body; the number of the cylindrical cavities corresponds to the number of pressure plates. The present invention acts on the thrust hemisphere through the elongation and contraction of the piezoelectric ceramic driver, promotes the radial movement of the film plane, and further drives the radial movement of the semi-cylinder, so as to realize the 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 to suppress the vibration of the shaft neck and control the axis trajectory.

Description

Technical Field

[0001] The present invention relates to the technical field of bearings, and in particular to a liquid dynamic pressure bearing. Background Art

[0002] Sliding bearings are bearings that work under sliding friction. According to the way they generate oil film pressure, they can be divided into two categories: hydrodynamic bearings and static pressure bearings. When hydrodynamic bearings are in working state, they are liquid hydrodynamic lubrication, and 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. It is an ideal working state, and it has the characteristics of smooth operation, simple structure, low noise, greater rigidity and overload resistance.

[0003] Liquid dynamic pressure bearings are divided into liquid dynamic pressure radial bearings and liquid dynamic pressure thrust bearings. Liquid dynamic pressure radial bearings are further divided into single oil wedge and multi-oil wedge. Multi-oil wedge liquid dynamic pressure 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 center of the journal coincides with the geometric center of the bearing, there is 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 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 additional oil film pressure, which can improve the stability of the bearing operation.

[0004] At present, some existing liquid dynamic pressure shaft journals are prone to vibration, resulting in the deviation of the axis trajectory. How to solve the above technical problems is a technical problem that needs to be solved in the current bearing technology field. Summary of the invention

[0005] In view of the above technical problems, an embodiment of the present invention provides a liquid dynamic pressure bearing to solve the problems raised in the above background technology.

[0006] The present invention provides the following technical solution: a liquid dynamic pressure bearing, comprising a bearing, a journal matched with the bearing, the bearing comprising a body, and further comprising:

[0007] At least three pressing plates, the pressing plates being evenly spaced and arranged on the inner cylindrical surface of the body;

[0008] An elastic film, the elastic film is surrounded by a pressing plate and arranged on the inner cylindrical surface of the main body;

[0009] A cylindrical cavity, wherein the cylindrical cavity is arranged between two adjacent pressing plates on the cylindrical surface of the body; the number of the cylindrical cavities corresponds to the number of pressing plates;

[0010] A driving member, wherein the driving member is disposed in the cylindrical cavity;

[0011] A push block, wherein the push block is disposed on the driving member, and the driving member and the elastic film are connected via the push block;

[0012] A semi-cylinder is arranged on the elastic film; a wedge-shaped gap A and a wedge-shaped gap B are formed between the cylindrical surface of the semi-cylinder and the journal.

[0013] Preferably, an annular groove and a baffle covering the annular groove are provided on the side surface of the main body, and the baffle and the annular groove together form a closed annular oil supply cavity.

[0014] Preferably, the outer cylindrical surface of the main body is provided with a first main oil supply hole A and a second main oil supply hole B, and the elastic film and the pressure plate are respectively provided with coaxial film through holes and pressure plate through holes; the first main oil supply hole A and the second main oil supply hole B are respectively connected to the annular oil supply cavity, and the annular oil supply cavity is connected to the film through hole and the pressure plate through hole in sequence through at least one oil delivery hole.

[0015] Preferably, the oil delivery hole includes an axial oil supply hole and a radial oil supply hole, and the annular oil supply cavity, the axial oil supply hole and the radial oil supply hole are connected in series in sequence; the radial oil supply hole is connected to the film through hole and the pressure plate through hole in sequence.

[0016] Preferably, the elastic film forms a film connection position at the pressure plate connection position, and forms a film plane between two adjacent pressure plates, and the semi-cylinder is arranged on the film plane.

[0017] Preferably, the driving element is a piezoelectric ceramic driver.

[0018] Preferably, the push block is a thrust hemisphere.

[0019] Preferably, a threaded hole A is formed on the outer cylindrical surface of the main body at a position corresponding to the cylindrical cavity, and a bolt is arranged in the threaded hole A.

[0020] Preferably, the elastic film is connected to the semi-cylinder through a flexible hinge A and a flexible hinge B, and a film through hole is provided at the film connection position of the elastic film.

[0021] Preferably, the pressure plate includes a pressure plate arm and two fixed ends, the fixed ends are provided with threaded holes B, the pressure plate is connected to the side wall of the body by screws, and the pressure plate arm is provided with a pressure plate through hole.

[0022] A liquid dynamic bearing provided by an embodiment of the present invention has the following beneficial effects:

[0023] (1) The present invention acts on the thrust hemisphere through the extension and contraction of the piezoelectric ceramic driver, pushing the film plane to move radially, further driving the semi-cylinder 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, thus realizing the control of the oil film force, which can be used to suppress the vibration of the journal and control the axis trajectory;

[0024] (2) By actively controlling the size of the wedge gap, the dynamic pressure and the oil film force can be actively controlled to improve the rotation accuracy of the journal;

[0025] (3) A flexible hinge is provided on the elastic film to further improve the sensitivity of the active control semi-cylinder. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural schematic diagram of a liquid dynamic pressure bearing of the present invention;

[0027] Figure 2 A transverse cross-sectional view of a liquid dynamic pressure bearing of the present invention;

[0028] Figure 3 An axial view of a liquid dynamic pressure bearing of the present invention;

[0029] Figure 4 It is a structural schematic diagram of the baffle in the present invention;

[0030] Figure 5 It is a structural schematic diagram of the pressure plate in the present invention;

[0031] Figure 6 It is a perspective view of the lubricating oil circuit in the present invention;

[0032] In the figure, 1 is a bearing; 11 is a body; 111 is a threaded hole A; 112 is a cylindrical cavity; 113 is a main oil supply hole A; 114 is a main oil supply hole B; 115 is an axial oil supply hole A; 116 is an axial oil supply hole B; 117 is an axial oil supply hole C; 118 is an axial oil supply hole D; 119 is an axial oil supply hole E; 1110 is a radial oil supply hole A; 1111 is a radial oil supply hole B; 1112 is a radial oil supply hole C; 1113 is a radial oil supply hole D; 1114 is a radial oil supply hole E; 1115 is an annular groove; 12 is an elastic film ; 121 film plane; 122 flexible hinge A; 123 flexible hinge B; 124 film connection position; 125 film through hole; 13 pressure plate; 131 pressure plate arm; 132 fixed end; 133 pressure plate through hole; 134 threaded hole B; 14 thrust hemisphere; 15 piezoelectric ceramic driver; 16 bolt; 17 semi-cylinder; 171 semi-cylinder plane; 172 semi-cylinder cylindrical surface; 173 wedge gap A; 174 wedge gap B; 18 baffle; 181 threaded hole C; 2 shaft neck. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0034] Example 1, see Figure 1-Figure 4 , Figure 1 It is a structural schematic diagram of a liquid dynamic pressure bearing of the present invention; Figure 2 A transverse cross-sectional view of a liquid dynamic pressure bearing of the present invention; Figure 3 An axial view of a liquid dynamic pressure bearing of the present invention; Figure 4 It is a schematic diagram of the structure of the baffle in the present invention.

[0035] A liquid dynamic pressure bearing comprises a bearing 1 and a journal 2 matched with the bearing 1. The bearing 1 comprises a body 11 and further comprises:

[0036] At least three pressing plates 13, the pressing plates 13 are evenly spaced and arranged on the inner cylindrical surface of the body 11;

[0037] The elastic film 12 is surrounded by the pressing plate 13 and arranged on the inner cylindrical surface of the body 11; the elastic film 12 forms a film connection position 124 at the connection position of the pressing plate 13, and forms a film plane 121 between two adjacent pressing plates 13, and the semi-cylinder 17 is arranged on the film plane 121;

[0038] A cylindrical cavity 112, wherein the cylindrical cavity 112 is disposed between two adjacent pressing plates 13 on the inner cylindrical surface of the body 11; the number of the cylindrical cavities 112 corresponds to the number of the pressing plates 13;

[0039] A driving member 15, wherein the driving member 15 is disposed in the cylindrical cavity 112;

[0040] A push block 14, wherein the push block 14 is disposed on the driving member 15, and the driving member 15 and the elastic film 12 are connected via the push block 14;

[0041] The semi-cylinder 17 includes a semi-cylindrical plane 171 and a cylindrical surface 172. The semi-cylindrical plane 171 is fixedly connected to the film plane 121. The semi-cylindrical plane 171 and the film plane 121 are fixedly connected by gluing or welding.

[0042] A wedge-shaped gap A173 and a wedge-shaped gap B174 are formed between the cylindrical surface 172 of the semi-cylinder 17 and the journal 2; the wedge-shaped gap A173 and the wedge-shaped gap B174 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.

[0043] Preferably, the driving member 15 is a piezoelectric ceramic driver.

[0044] Preferably, the push block 14 is a thrust hemisphere.

[0045] By controlling the extension or contraction of the piezoelectric ceramic driver 15 and driving the semi-cylinder 17 to move radially, the sizes of the wedge gap A173 and the wedge gap B174 can be actively controlled.

[0046] It should be noted that the contact between the thrust hemisphere and the film plane 121 is point contact. In actual operation, the contact point can be adaptively adjusted according to the applied load and processing and assembly errors. At the same time, the lateral friction between the thrust hemisphere and the film plane is greatly reduced.

[0047] The method of using a liquid hydrodynamic bearing of the present invention is as follows: when working, the piezoelectric ceramic driver 12 is extended and shortened to act on the thrust hemisphere 14, pushing the film plane 121 to move radially, further driving the semi-cylinder 17 to move radially, thereby realizing active control of the size of the wedge gap A173 and the wedge gap B174.

[0048] Through research, it was found that the size of the wedge gap determines the size of the dynamic pressure. Under a certain journal speed and lubricating oil viscosity, the smaller the wedge gap, the greater the dynamic pressure. By controlling the size of the wedge gap A173 and the wedge gap B174, the size of the dynamic pressure can be controlled; the product of the dynamic pressure and the area is the oil film force, which means that the control of the oil film force is achieved, which can be used to suppress journal vibration and actively control the axis trajectory.

[0049] It should be noted that 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 a certain journal speed and lubricating oil viscosity, the smaller the wedge clearance, the greater the dynamic pressure.

[0050] Therefore, 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, improves the rotation accuracy of the journal, and can also suppress the journal vibration and actively control the axis trajectory.

[0051] Example 2, see Figure 1-Figure 6, Figure 5 It is a structural schematic diagram of the pressure plate in the present invention; Figure 6 It is a perspective view of the lubricating oil circuit in the present invention.

[0052] The side of the body 11 is provided with an annular groove 1115 and a baffle 18 covering the annular groove 1115 . The baffle 18 and the annular groove 1115 together form a closed annular oil supply chamber. The baffle 18 is installed on the side of the body 11 through a threaded hole C181 on the baffle 18 .

[0053] The outer cylindrical surface of the main body 11 is provided with a first main oil supply hole A113 and a second main oil supply hole B114, and the elastic film 12 and the pressure plate 13 are respectively provided with a coaxial film through hole 125 and a pressure plate through hole 133; the first main oil supply hole A113 and the second main oil supply hole B114 are respectively connected to the annular oil supply cavity, and the annular oil supply cavity is connected to the film through hole 125 and the pressure plate through hole 133 in sequence through at least one oil delivery hole.

[0054] The oil delivery hole includes an axial oil supply hole and a radial oil supply hole. The annular oil supply cavity, the axial oil supply hole and the radial oil supply hole are connected in series in sequence. The radial oil supply hole is connected to the film through hole 125 and the pressure plate through hole 133 in sequence.

[0055] It should be noted that, in the embodiment of the present invention, preferably, five oil delivery holes are provided in the body 11, such as:

[0056] There are five axial oil supply holes, namely, axial oil supply hole A115, axial oil supply hole B116, axial oil supply hole C117, axial oil supply hole D118 and axial oil supply hole E119; and there are five radial oil supply holes corresponding to the axial oil supply holes, namely, radial oil supply hole A1110, radial oil supply hole B1111, radial oil supply hole C1112, radial oil supply hole D1113 and radial oil supply hole E1114.

[0057] The axial oil supply hole A115, axial oil supply hole B116, axial oil supply hole C117, axial oil supply hole D118 and axial oil supply hole E119 are respectively connected with the radial oil supply hole A1110, radial oil supply hole B1111, radial oil supply hole C1112, radial oil supply hole D1113 and radial oil supply hole E1114; the radial oil supply hole A1110, radial oil supply hole B1111, radial oil supply hole C1112, radial oil supply hole D1113 and radial oil supply hole E1114 are further respectively connected with the film through hole 125 and the pressure plate through hole 133.

[0058] Preferably, in the embodiment of the present invention, the first main oil supply hole A113 and the second main oil supply hole B114 are connected to the axial oil supply hole A115 and the axial oil supply hole B116 respectively, and then communicate with the annular oil supply cavity through the axial oil supply hole A115 and the axial oil supply hole B116, and the other ends of the axial oil supply hole A115 and the axial oil supply hole B116 are communicated with the radial oil supply hole A1110 and the radial oil supply hole B1111 respectively;

[0059] The lubricating oil added through the first main oil supply hole A113 and the second main oil supply hole B114 is collected in the annular oil supply cavity, and then flows through the annular oil supply cavity 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.

[0060] A liquid hydrodynamic bearing lubricating oil circuit of the present invention 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 oil supply cavity, flows from the annular oil supply cavity 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 125 to reach the bearing gap; driven by the rotation of the shaft neck, it reaches the wedge gap A173 and the wedge gap B174.

[0061] Furthermore, a threaded hole A111 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 A111 . The piezoelectric ceramic driver 15 can be replaced by removing the bolt 16 .

[0062] Furthermore, the elastic film 12 is connected to the semi-cylinder 17 via the flexible hinge A122 and the flexible hinge B123. The deformation stiffness of the flexible hinge is extremely low, and the film is easily bent and deformed at the flexible hinge.

[0063] Furthermore, the pressure plate 13 includes a pressure plate arm 131 and two fixed ends 132, the fixed ends 132 are provided with threaded holes B134, the body 11 is provided with threaded fixing holes matching the threaded holes B134, and the pressure plate 13 is connected to the side wall of the body 11 by screws passing through the threaded holes B134 and the threaded fixing holes.

[0064] A film through hole 125 is formed on the film connecting position 124 of the elastic film 12 ; and a pressing plate through hole 133 is formed on the pressing plate arm 131 .

[0065] A liquid hydrodynamic bearing provided by an embodiment of the present invention has the following beneficial effects: the present invention acts on the thrust hemisphere through the extension and contraction of the piezoelectric ceramic driver, thereby pushing the film plane to move radially, and further driving the semi-cylinder to move radially, 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. 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 to suppress the vibration of the journal and control the axis trajectory; by actively controlling the size of the wedge gap, the dynamic pressure and the oil film force can be actively controlled to improve the rotation accuracy of the journal; a flexible hinge is provided on the elastic film, which can further improve the sensitivity of the active control of the semi-cylinder.

[0066] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0067] In the present invention, unless otherwise clearly stipulated and limited, the terms such as "installation", "setting", "connection", "fixation" and "screw-on" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. Unless otherwise clearly defined, for ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0068] It is understandable that those skilled in the art can make equivalent substitutions or changes based on the technical solution and concept of the present invention, and all these changes or substitutions should fall within the protection scope of the claims attached to the present invention.

Claims

1. A liquid dynamic pressure bearing, comprising a bearing (1), a journal (2) matched with the bearing (1), wherein the bearing (1) comprises a body (11), characterized in that: Also includes: At least three pressing plates (13), wherein the pressing plates (13) are evenly spaced and arranged on the inner cylindrical surface of the body (11); An elastic film (12), wherein the elastic film (12) is surrounded by a pressure plate (13) and arranged on the inner cylindrical surface of the body (11); A cylindrical cavity (112), wherein the cylindrical cavity (112) is disposed between two adjacent pressing plates (13) on the inner cylindrical surface of the body (11); the number of the cylindrical cavities (112) corresponds to the number of the pressing plates (13); A driving member (15), wherein the driving member (15) is disposed in the cylindrical cavity (112); the driving member (15) is a piezoelectric ceramic driver; A push block (14), wherein the push block (14) is arranged on a driving member (15), and the driving member (15) and the elastic film (12) are connected via the push block (14); the push block (14) is a thrust hemisphere; and the contact between the thrust hemisphere (14) and the film plane (121) is point contact; The elastic film (12) forms a film connection position (124) at the connection position of the pressure plate (13), and forms a film plane (121) between two adjacent pressure plates (13), and the semi-cylinder (17) is arranged on the film plane (121); The elastic film (12) is connected to the semi-cylinder (17) via a flexible hinge A (122) and a flexible hinge B (123), and a film through hole (125) is provided on the film connection position (124) of the elastic film (12); A semi-cylinder (17) is arranged on the elastic film (12); a wedge-shaped gap A (173) and a wedge-shaped gap B (174) are formed between the cylindrical surface (172) of the semi-cylinder (17) and the shaft neck (2).

2. A liquid dynamic bearing according to claim 1, characterized in that an annular groove (1115) and a baffle (18) covering the annular groove (1115) are provided on the side of the body (11), and the baffle (18) and the annular groove (1115) together form a closed annular oil supply chamber.

3. A liquid hydrodynamic bearing according to claim 2, characterized in that a first main oil supply hole A (113) and a second main oil supply hole B (114) are opened on the outer cylindrical surface of the body (11), and coaxial film through holes (125) and pressure plate through holes (133) are respectively provided on the elastic film (12) and the pressure plate (13); the first main oil supply hole A (113) and the second main oil supply hole B (114) are respectively connected to the annular oil supply cavity, and the annular oil supply cavity is connected to the film through hole (125) and the pressure plate through hole (133) in sequence through at least one oil delivery hole.

4. A liquid hydrodynamic bearing according to claim 3, characterized in that the oil supply hole includes an axial oil supply hole and a radial oil supply hole, and the annular oil supply cavity, the axial oil supply hole and the radial oil supply hole are connected in series in sequence; the radial oil supply hole is connected to the film through hole (125) and the pressure plate through hole (133) in sequence.

5. A liquid dynamic bearing according to claim 1, characterized in that a threaded hole A (111) is opened 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).

6. A liquid hydrodynamic bearing according to claim 1, characterized in that the pressure plate (13) includes a pressure plate arm (131) and two fixed ends (132), a threaded hole B (134) is opened on the fixed end (132), the pressure plate (13) is connected to the side wall of the body (11) by screws, and a pressure plate through hole (133) is opened on the pressure plate arm (131).

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