Cold working die for elastic supporting foil of dynamic pressure gas thrust bearing and preparation method of cold working die

Abstract

The invention discloses a cold working die of a dynamic pressure gas thrust bearing elastic supporting foil and a preparation method, the cold working die comprises an annular flexible polyvinyl chloride plastic upper die and a hard lower die, key holes corresponding to tongue pieces on the elastic supporting foil in a one-to-one mode are distributed in the hard lower die, core rods are inserted into the key holes, and the core rods are connected with the elastic supporting foil in a one-to-one mode. The mandrels have right trapezoid sections, the upper sides of the mandrels form a uniform gradient, and the gradient can be adjusted by replacing the mandrels; and during mold closing, the flexible polyvinyl chloride plastic upper mold is pressed to deform and is tightly attached to the hard lower mold. The forming precision of the elastic supporting foil can be improved, the warping degree of the tongue piece can be flexibly adjusted, and the machining cost is saved.

Description

Technical Field

[0001] The invention relates to a dynamic pressure gas thrust bearing, and in particular to a cold working die and a preparation method of an elastic supporting foil of a dynamic pressure gas thrust bearing. Background Art

[0002] The hydrodynamic gas thrust bearing is a self-acting bearing with an elastic support structure, which is mainly composed of a bottom foil, a supporting corrugated foil and a top foil. Since air is used as the lubricating medium and an elastic support structure is integrated, the bearing is a passive adjustment bearing. Compared with traditional oil film bearings and rolling bearings, it has the advantages of strong adaptability, clean and pollution-free, high speed, low friction power consumption, strong vibration resistance, wide operating temperature range, and low maintenance cost.

[0003] Due to its unique advantages, hydrodynamic gas thrust bearings have been widely used in many fields. For example, in the field of aerospace, hydrodynamic gas thrust bearings are widely used in the support and positioning of high-speed rotating parts, such as aircraft engines, inertial navigation systems, etc.; in the field of precision machinery, hydrodynamic gas thrust bearings are widely used in precision machine tools, measuring instruments and other equipment due to their high precision, low friction and low power consumption; in the field of medical equipment, hydrodynamic gas thrust bearings are used in medical equipment that requires high precision and low friction, such as surgical robots, precision medical instruments, etc.; in the field of energy, hydrodynamic gas thrust bearings are used in high-speed turbine machinery, cryogenic turbines and other equipment to achieve efficient energy conversion and transmission.

[0004] At present, the processing of elastic support foils for hydrodynamic gas thrust bearings is very complicated, especially for bottom foils with complex structures, which require customized special molds for pressing. Since the upper and lower molds are manufactured separately, it is often difficult to meet the precision requirements of the matching dimensions, and thus it is difficult for the elastic support foils to meet the molding precision requirements (micrometer level). Low-precision products and high manufacturing costs caused by complicated processing are not conducive to the application and development of hydrodynamic gas thrust bearings. On the other hand, in experiments, it is often necessary to adjust the warpage of the tongue of the elastic support foil, but traditional molds are usually not adjustable after manufacturing. Summary of the invention

[0005] Purpose of the invention: The first purpose of the present invention is to provide a cold working die for the elastic support foil of a dynamic pressure gas thrust bearing, which can meet the precision requirements of the elastic support foil, facilitate the adjustment of the tongue warp of the elastic support foil, and save processing costs; The second purpose of the present invention is to provide a method for preparing the elastic support foil of a dynamic pressure gas thrust bearing based on the cold working die.

[0006] Technical solution: The cold working die of the elastic support foil of the dynamic pressure gas thrust bearing described in the present invention comprises an upper die seat and a lower die seat, a flexible polyvinyl chloride plastic upper die in the shape of an annular ring is fixed to the bottom of the upper die seat; a hard lower die is fixed to the top of the lower die seat, a plurality of key holes are distributed on the top of the hard lower die, the elastic support foil is a thin annular spring leaf, and the key hole positions correspond to the tongue pieces of the elastic support foil one by one; a core rod is inserted into the key hole, the core rod has a right-angle trapezoidal cross section, and the upper side of each core rod forms a uniform slope, and the slope can be Adjustment is performed by replacing the core rod; a center guide column and a positioning pin are also provided on the top of the hard lower die; the center guide column is matched with the inner hole of the flexible polyvinyl chloride plastic upper die and is used to sleeve the elastic supporting foil; the positioning pin is used to cooperate with the semicircular arc ear on the edge of the elastic supporting foil to fix the elastic supporting foil; the upper die base and the lower die base are installed on the hydraulic press, and the center guide column can be inserted into the inner hole of the flexible polyvinyl chloride plastic upper die when the die is closed, and the flexible polyvinyl chloride plastic upper die covers all the tongues of the elastic supporting foil.

[0007] Furthermore, the flexible polyvinyl chloride plastic is obtained by adding 5 to 10 parts of plasticizer to 1 part of PVC resin.

[0008] Furthermore, the slope is 3° to 10°.

[0009] Furthermore, there are multiple positioning pins, which are arranged at intervals along the circumferential direction.

[0010] Furthermore, the elastic supporting foil is made of GH145 high temperature nickel-based alloy, and the hard lower die, lower die seat, positioning pin, central guide column, core rod and upper die seat are made of stainless steel.

[0011] Furthermore, the hard lower die and the lower die base are fixed by bolts.

[0012] Furthermore, the flexible polyvinyl chloride plastic upper mold and the upper mold base are bonded by strong glue.

[0013] Furthermore, bolt holes are provided on the upper die base and the lower die base, and the two are fixed to the hydraulic press by bolts.

[0014] The method for preparing the elastic support foil of the dynamic pressure gas thrust bearing of the present invention adopts the cold working mold of the elastic support foil of the dynamic pressure gas thrust bearing, and the preparation method comprises:

[0015] 1) Using slow wire cutting technology to cut the elastic supporting foil to form the tongue and the semicircular arc ear on the edge;

[0016] 2) Insert the mandrel into each key hole on the top of the hard lower die, and the direction of the upper slope of the mandrel is determined as required;

[0017] 3) Insert the elastic support foil into the central guide column, align the semicircular arc ear on the edge with the positioning pin, fix the elastic support foil on the hard lower mold, and press gently to make the tongue fit the upper slope of the core rod to produce pre-deformation;

[0018] 4) The cold working mold is installed on a hydraulic press, and the upper and lower molds are closed. The flexible polyvinyl chloride plastic upper mold is deformed and fits tightly with the hard lower mold. The pressure is maintained for more than 20 minutes to form the elastic supporting foil.

[0019] Furthermore, the hydraulic press adopts a hydraulic press of more than 50t, and the mold clamping pressure is 200-250KN.

[0020] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: the cold working die provided by the present invention has a flexible upper die and a rigid lower die. When the hydraulic press applies pressure, the flexible upper die can adaptively change its shape and fit the rigid lower die, thereby avoiding the problem of low matching accuracy of the traditional upper and lower dies, and can meet the precision requirements of the elastic support foil. In addition, by replacing core rods with different slopes, the warping of the tongue can be flexibly adjusted. The present invention no longer requires the customization of special molds, which can save processing costs, and the elastic support foil can be tested many times and reused repeatedly. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic structural diagram of an elastic supporting foil in an embodiment of the present invention;

[0022] Figure 2 It is a structural schematic diagram of a cold working die of an elastic supporting foil of a dynamic pressure gas thrust bearing provided by an embodiment of the present invention;

[0023] Figure 3 It is a schematic diagram of the combined structure of the upper mold base and the flexible polyvinyl chloride plastic upper mold in an embodiment of the present invention;

[0024] Figure 4 It is a schematic diagram of the combined structure of the lower die base and the hard lower die in an embodiment of the present invention;

[0025] Figure 5 Schematic diagram of the structure of the core rod in the embodiment of the present invention. DETAILED DESCRIPTION

[0026] The present invention will be further described below in conjunction with the accompanying drawings.

[0027] Attached Figures 1 to 5 The reference numerals in the figures are as follows:

[0028] 11, elastic supporting foil; 12, tongue piece; 21, upper die seat; 22, flexible polyvinyl chloride plastic upper die; 31, lower die seat; 32, bolt hole; 33, hard lower die; 34, positioning pin; 35, core rod; 36, center guide column.

[0029] like Figures 2 to 5 As shown, the embodiment of the present invention provides a cold working die for an elastic support foil of a dynamic pressure gas thrust bearing, and the cold working die is used to prepare Figure 1 The elastic support foil 11 shown is a thin circular spring with a thickness of 0.1 mm. The material is GH145 high-temperature nickel-based alloy. The diameter of the central circular hole of the elastic support foil 11 is 24 mm. There are 16 tongues 12 of the same shape and size distributed on the elastic support foil 11, which are divided into two circles, 8 in each circle. These tongues 12 need to be processed into a uniform warpage to play a supporting role. The edge of the elastic support foil 11 has four semicircular arc ears evenly distributed along the circumference, and the diameter of the semicircular arc ears is 4 mm. The maximum contour surface diameter of the elastic support foil 11 is 55.5 mm.

[0030] The cold working die comprises an upper die seat 21 and a lower die seat 31. A flexible polyvinyl chloride plastic upper die 22 in a circular shape is fixed to the bottom of the upper die seat 21 by strong adhesive. The flexible polyvinyl chloride plastic is obtained by adding 5 to 10 parts of plasticizer to 1 part of PVC resin, so that the flexible polyvinyl chloride plastic upper die 22 is easy to deform when under pressure. In this embodiment, the inner diameter of the flexible polyvinyl chloride plastic upper die 22 is 20 to 26 mm, and the outer diameter is 48 to 50 mm.

[0031] A hard lower die 33 with a thickness of 10 to 25 mm is fixed to the top of the lower die seat 31 by bolts. There are 16 key holes distributed on the top of the hard lower die 33. The positions of the key holes correspond to the tongue pieces 12 of the elastic supporting foil 11. A core rod 35 is inserted into the key hole. The core rod 35 has a right-angle trapezoidal cross section. The upper side of each core rod 35 forms a uniform slope, and the slope can be adjusted by replacing the core rod 35. The adjustable range of the slope is 3° to 10°.

[0032] A central guide column 36 and three positioning pins 34 are also provided on the top of the hard lower mold 33. The central guide column 36 is matched with the inner hole of the flexible polyvinyl chloride plastic upper mold 22 and is used to sleeve the elastic support foil 11. The three positioning pins 34 are arranged at intervals along the circumference, and their positions match the semicircular arc ears on the edge of the elastic support foil 11. The positioning pins 34 are used to match the semicircular arc ears on the edge of the elastic support foil 11 to fix the elastic support foil 11.

[0033] The upper die base 21 and the lower die base 31 are both provided with bolt holes 32, and the two are fixed to the hydraulic press by bolts. The central guide column 36 can be inserted into the inner hole of the flexible polyvinyl chloride plastic upper die 22 when the mold is closed, and the flexible polyvinyl chloride plastic upper die 22 covers all the tongues 12 of the elastic supporting foil 11.

[0034] In this embodiment, the hard lower die 33 , the lower die base 31 , the positioning pin 34 , the central guide column 36 , the core rod 35 and the upper die base 21 are made of stainless steel.

[0035] The embodiment of the present invention further provides a method for preparing an elastic support foil of a dynamic pressure gas thrust bearing, using a cold working die of the elastic support foil of the dynamic pressure gas thrust bearing according to the embodiment of the present invention, the preparation method comprises:

[0036] 1) The elastic supporting foil 11 is cut by a slow-wire cutting process to form a tongue 12 and a semicircular arc ear on the edge. The slow-wire cutting process can better ensure the precision size of the elastic supporting foil 11;

[0037] 2) Insert the mandrel 35 into each key hole at the top of the hard lower die 33, with the upper side of the mandrel 35 sloped, the inner circle facing outwards, and the outer circle facing inwards;

[0038] 3) Insert the elastic supporting foil 11 into the central guide column 36, align the semicircular arc ear on the edge with the positioning pin 34, fix the elastic supporting foil 11 on the hard lower mold 33, and press gently to make the tongue 12 fit the upper slope of the core rod 35 to produce pre-deformation;

[0039] 4) Install the cold working mold on a hydraulic press of more than 50t, apply a pressure of 200-250KN, close the upper and lower molds, deform the flexible polyvinyl chloride plastic upper mold 22, and fit tightly with the hard lower mold 33 (filling and covering the foil surface), maintain the pressure for more than 20 minutes, and form the elastic supporting foil 11.

[0040] In summary, in view of the processing difficulties of the consistency of the curved surface forming of the bottom foil tongue of the thrust bearing and the problem of low matching accuracy of the upper and lower molds, the present invention proposes a "flexible adaptive" cold working mold for the bottom foil of the thrust bearing, which uses a flexible upper mold to match the rigid lower mold, and the protruding part of the lower mold is replaced by a core rod with a trapezoidal cross-section. The core rods with different slopes can be replaced to prepare tongue structures with different warping degrees. The upper mold is a flexible polyvinyl chloride plastic ring with the ability to deform under pressure. The cold working mold has the characteristics of high precision and easy manufacturing, and can avoid the stress concentration problem caused by uneven matching of the upper and lower molds, improve processing accuracy, and save costs.

Claims

1. A cold working die for elastic support foil of a dynamic pressure gas thrust bearing, characterized in that: The invention comprises an upper die base (21) and a lower die base (31), wherein a flexible polyvinyl chloride plastic upper die (22) in the shape of an annular ring is fixed at the bottom of the upper die base (21); a hard lower die (33) is fixed at the top of the lower die base (31), and a plurality of key holes are distributed on the top of the hard lower die (33); the elastic supporting foil (11) is a thin annular spring sheet, and the key hole positions correspond to the tongue pieces (12) of the elastic supporting foil (11) one by one; a core rod (35) is inserted into the key hole, and the core rod (35) has a right-angle trapezoidal cross section, and the upper side of each core rod (35) forms a uniform slope, and the slope can be adjusted by replacing the core rod (35); the hard lower die (33) A central guide column (36) and a positioning pin (34) are also provided at the top. The central guide column (36) is matched with the inner hole of the flexible polyvinyl chloride plastic upper mold (22) and is used to sleeve the elastic supporting foil (11); the positioning pin (34) is used to cooperate with the semicircular arc ear on the edge of the elastic supporting foil (11) to fix the elastic supporting foil (11); the upper mold base (21) and the lower mold base (31) are installed on the hydraulic press, and the central guide column (36) can be inserted into the inner hole of the flexible polyvinyl chloride plastic upper mold (22) when the mold is closed, and the flexible polyvinyl chloride plastic upper mold (22) covers all the tongues (12) of the elastic supporting foil (11).

2. The cold working die according to claim 1, characterized in that: Flexible polyvinyl chloride plastic is obtained by adding 5 to 10 parts of plasticizer to 1 part of PVC resin.

3. The cold working die according to claim 1, characterized in that: The slope is 3° to 10°.

4. The cold working die according to claim 1, characterized in that: There are a plurality of positioning pins (34), which are arranged at intervals along the circumferential direction.

5. The cold working die according to claim 1, characterized in that: The elastic supporting foil (11) is made of GH145 high temperature nickel-based alloy, and the hard lower die (33), the lower die seat (31), the positioning pin (34), the central guide column (36), the core rod (35) and the upper die seat (21) are made of stainless steel.

6. The cold working die according to claim 1, characterized in that: The hard lower die (33) and the lower die base (31) are fixed by bolts.

7. The cold working die according to claim 1, characterized in that: The flexible polyvinyl chloride plastic upper mold (22) is bonded to the upper mold base (21) by strong glue.

8. The cold working die according to claim 1, characterized in that: The upper die base (21) and the lower die base (31) are both provided with bolt holes (32), and the two are fixed on the hydraulic press by bolts.

9. A method for preparing an elastic support foil for a dynamic pressure gas thrust bearing, characterized in that: A cold working die for the elastic support foil of a dynamic pressure gas thrust bearing according to any one of claims 1 to 8 is used, and the preparation method comprises: 1) using a slow-wire cutting process to cut the elastic supporting foil (11) to form a tongue (12) and a semicircular arc ear at the edge; 2) inserting a mandrel (35) into each key hole at the top of the hard lower die (33), and the direction of the upper slope of the mandrel (35) is determined as required; 3) inserting the elastic supporting foil (11) into the central guide column (36), aligning the semicircular arc ear on the edge with the positioning pin (34), fixing the elastic supporting foil (11) on the hard lower mold (33), and gently pressing to make the tongue (12) fit the upper slope of the core rod (35) to produce pre-deformation; 4) The cold working die is mounted on a hydraulic press, and the upper and lower dies are closed, so that the flexible polyvinyl chloride plastic upper die (22) is deformed and closely fits with the hard lower die (33), and the pressure is maintained for more than 20 minutes to form the elastic supporting foil (11).

10. The preparation method according to claim 9, characterized in that: The hydraulic press uses a hydraulic press of more than 50t, and the mold clamping pressure is 200-250KN.

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