Manufacturing method of single-layer wave spring and machining die used by manufacturing method

Abstract

The invention discloses a manufacturing method of a single-layer wave spring and a machining mold used by the manufacturing method. The manufacturing method comprises the following steps of S1, linear cutting, wherein a plate is cut into circular ring pieces; s2, pressure forming is conducted on the cut workpiece, specifically, the circular ring piece manufactured in the step S1 is put into a machining die, slow pressure forming is conducted through a press machine, and forming is conducted under the set pressure of 1.8-2.2 Mpa; s3, quenching the formed workpiece, wherein the quenching temperature is 860-880 DEG C, and the quenching medium is oil; and S4, tempering the quenched workpiece: putting the workpiece into a shaping processing mold for tempering at the tempering temperature of 300-420 DEG C, and carrying out inert gas protection in the heat preservation process. The elastic stability of the single-layer closed wave spring can be improved, the product percent of pass is 75% or above, and the rebound problem in the industrial mass production process of the single-layer closed wave spring is solved.

Description

Technical Field

[0001] This invention relates to a method for manufacturing a single-layer wave spring and the processing mold used therein, belonging to the field of single-layer wave spring processing technology. Background Technology

[0002] The excellent mechanical properties of single-layer closed wave springs have enabled their widespread application in various fields, making them inseparable from modern industry and people's lives. Single-layer closed wave springs are often manufactured using stamping, a process whose results are easily affected by various factors, such as die precision, material properties, and stamping equipment. Therefore, during the stamping process, the product will experience a series of manufacturing errors due to these factors, leading to changes in its performance. Single-layer closed wave springs manufactured using traditional processes have poor fatigue resistance and suffer from low machining accuracy, making it difficult to achieve the desired processing precision.

[0003] A search revealed that Chinese patent document CN115502308A discloses a single-layer wave spring and its processing method. The single-layer wave spring uses a rectangular cross-section material with rounded corners on all four sides, which avoids stress concentration, improves fatigue life, and enhances mechanical properties. The corresponding processing method includes steps such as winding the rounded rectangular cross-section steel wire, laser welding, annealing, cold stamping wave forming, heat treatment, and surface treatment. This solves the problems of low material utilization and stress concentration leading to fatigue failure of the wave spring under alternating loads in current traditional processes.

[0004] Chinese patent document CN115707551A discloses a stretch forming process for a single-layer closed wave spring, which includes the following steps: 1. Calculating the material usage according to design requirements; 2. Vacuum annealing the raw material of the part, with the hardness of the annealed part ≤25HRC; 3. Cold stamping the part in sheet metal condition; 4. Vacuum quenching the formed part to achieve a shaping effect; 5. Cutting the quenched and shaped part to the target size and removing the initial support material; 6. Performing additional tempering to relieve stress. This invention can improve the elastic stability of single-layer closed wave springs and solve the springback problem during industrial mass production.

[0005] Chinese patent document CN114346130A discloses a precision machining control method for a single-layer closed wave spring. This machining control method includes the following steps: 1) According to the design requirements of the part to be machined, the raw material is formed into a ring-shaped blank using a die; 2) The ring-shaped blank from step 1) is cold-stamped to obtain a rough-machined part; 3) The rough-machined part obtained in step 2) is corrected so that its dimensions are consistent with the pre-fabricated height dimensions of the part to be machined, and the parallelism between the wave crests of the rough-machined part is maintained within 0.1 mm; 4) The corrected rough-machined part is heat-treated to obtain a semi-finished machined part; 5) The semi-finished machined part is subjected to high-pressure treatment to complete the machining. The wave spring manufactured by this invention has stable dimensions, reliable mechanical properties, and good fatigue and deformation resistance, fully meeting its service requirements in aero-engines.

[0006] However, in the current environment of eliminating outdated equipment and upgrading process equipment capabilities, adjustments need to be made to the wave spring process, and there is still room for further improvement in properties such as wave height difference and hardness. Summary of the Invention

[0007] The purpose of this invention is to provide a method for manufacturing a single-layer wave spring and the processing mold used therein. This invention eliminates the use of a punch press, and the single-layer wave spring manufactured has a lower wave height difference and higher hardness.

[0008] The technical solution of this invention: A method for manufacturing a single-layer wave spring, comprising the following steps:

[0009] S1. Wire EDM: Cutting sheet metal into circular rings;

[0010] S2. Pressure forming of the cut workpiece: Place the ring-shaped piece prepared in S1 into the processing mold, and use a press to slowly press and form it, with the pressure set at 1.8-2.2 MPa;

[0011] S3. Quench the formed workpiece: the quenching temperature is 860-880℃, and the quenching medium is oil;

[0012] S4. Tempering the quenched workpiece: Place the workpiece in a shaping mold for tempering at a temperature of 300-420℃, and use inert gas protection during the heat preservation process.

[0013] The aforementioned manufacturing method for a single-layer wave spring also includes S5. Inspection and warehousing: After inspecting the wave height difference and hardness of the single-layer wave spring, it is put into storage.

[0014] In the aforementioned method for manufacturing a single-layer wave spring, in step S2, the deformation process takes 1-2 seconds, and the pressure holding time takes 2-3 seconds.

[0015] In the aforementioned method for manufacturing a single-layer wave spring, in step S3, the quenching and holding time is 40-60 minutes.

[0016] In the aforementioned method for manufacturing a single-layer wave spring, in step S4, the tempering and heat preservation time is 60-80 minutes.

[0017] In the aforementioned method for manufacturing a single-layer wave spring, the inert gas in step S4 is argon.

[0018] A processing mold used in the aforementioned method for manufacturing a single-layer wave spring includes a pressure-relieving processing mold, which comprises an upper pressure-relieving processing mold and a lower pressure-relieving processing mold arranged opposite each other. The upper and lower pressure-relieving processing molds form a cavity mold when the molds are closed. The upper and lower pressure-relieving processing molds are respectively provided with a first guide hole and a second guide hole, and a guide post is inserted into the first and second guide holes. A limit ring is sleeved on the outer side wall of the upper end of the lower pressure-relieving processing mold, and a part removal groove is provided on the limit ring.

[0019] In the aforementioned method for manufacturing a single-layer wave spring, the limiting ring and the lower die for pressure relief are fitted with a clearance fit.

[0020] In the aforementioned method for manufacturing a single-layer wave spring, the processing mold further includes a tempering and shaping processing mold. The tempering and shaping processing mold includes an upper tempering and shaping mold and a lower tempering and shaping mold arranged opposite each other. When the upper tempering and shaping mold and the lower tempering and shaping mold are closed, a shaping cavity mold is formed. The upper tempering and shaping mold and the lower tempering and shaping mold are respectively provided with a first screw hole and a second screw hole. After the screw passes through the first screw hole and the second screw hole, its head extends to the top of the upper tempering and shaping mold. A nut is threaded onto the threaded section of the screw located above the upper tempering and shaping mold.

[0021] In the aforementioned method for manufacturing a single-layer wave spring, the bottom of the tempering and shaping lower mold is provided with a stepped countersunk hole, and the cap structure at the end of the screw is embedded in the stepped countersunk hole.

[0022] The beneficial effects of the present invention: Compared with the prior art, the present invention has the following advantages:

[0023] (1) The method of the present invention does not use traditional punching forming. The design of the pressure relief processing mold and the shaping processing mold makes the spring have a lower wave height difference;

[0024] (2) The quenching process forms a thin and hard surface layer on the spring, which makes the surface wear resistance better and the service life longer. If the quenching temperature is too high, the spring will be too brittle and prone to cracking. If the temperature is too low, the spring will not meet the wear resistance standards and the service life will be shortened. Therefore, after many experiments, the quenching temperature was selected as 860-880℃.

[0025] (3) The tempering step makes the microstructure tempered martensite, which has higher yield strength, elastic limit and higher toughness, and eliminates the high internal stress after quenching.

[0026] In summary, this invention can improve the elastic stability of single-layer closed wave springs, with a product qualification rate of over 75%, and solve the rebound problem during industrial mass production. Attached Figure Description

[0027] Figure 1 A schematic diagram of the cross-sectional structure of a pressure-relieving processing mold;

[0028] Figure 2 A cross-sectional structural diagram of the mold used for tempering and shaping.

[0029] Figure 3 Product image of a single-layer wave spring;

[0030] Figure 4 This is a schematic diagram of a single-layer wave spring.

[0031] Figure 5 This is a schematic diagram of the structure of the circular ring plate.

[0032] Reference numerals: 1-Upper mold for slow-pressure processing, 2-Lower mold for slow-pressure processing, 3-Limiting ring, 4-Guide post, 5-Part removal groove, 6-First guide hole, 7-Second guide hole, 8-Upper mold for tempering and shaping, 9-Lower mold for tempering and shaping, 10-First screw hole, 11-Second screw hole, 12-Screw, 13-Nut, 14-Shaping cavity mold, 15-Stepped countersunk hole, 16-Third screw hole. Detailed Implementation

[0033] The present invention will be further described below with reference to the accompanying drawings and embodiments, but this should not be construed as limiting the present invention.

[0034] Example 1

[0035] A method for manufacturing a single-layer wave spring includes the following steps:

[0036] S1. Wire EDM: Cutting sheet metal into circular rings. These rings have inner and outer diameters; see [reference needed]. Figure 5 As shown.

[0037] S2. Pressure forming of the cut circular ring workpiece: Place the circular ring prepared in S1 into the processing mold, and use a press to slowly press and form it. The pressure is set to 1.8 MPa; the deformation process takes 2 seconds, and the holding time is 3 seconds.

[0038] Among them, see the pressure relief processing mold. Figure 1As shown, the processing mold includes a pressure-reducing upper mold 1, a pressure-reducing lower mold 2, a limiting ring 3, and a guide post 4.

[0039] The upper mold 1 and the lower mold 2 for pressure relief processing are arranged opposite each other. When the molds are closed, the upper mold 1 and the lower mold 2 form a cavity. The upper mold 1 is provided with a first guide hole 6, and the lower mold 2 is provided with a second guide hole 7. One end of the guide post 4 is inserted into the first guide hole 6, and the other end of the guide post 4 is inserted into the second guide hole 7, so that the upper mold 1 and the lower mold 2 for pressure relief processing can close and open along the guide post 4.

[0040] The limiting ring 3 is sleeved on the outer wall of the protruding part at the end of the lower die 2 for slow pressure processing. The inner wall of the limiting ring 3 is fitted with the outer wall of the lower die 2 for slow pressure processing with a clearance fit, so that the limiting ring 3 can move freely up and down along the axial direction of the lower die 2 for slow pressure processing. The limiting ring 3 is provided with a part removal groove 5 for placing the blank and removing the workpiece.

[0041] After the upper mold 1 and lower mold 2 are closed, a press is used for slow pressing and forming. After forming, the mold is opened and the workpiece is removed. The guide pillar 4 plays a guiding role during the mold closing and opening processes, improving the processing accuracy.

[0042] S3. Quench the formed workpiece: the quenching temperature is 860℃, the quenching holding time is 40 minutes, and the quenching medium is oil.

[0043] S4. Tempering the quenched workpiece: Place the workpiece in a shaping mold for tempering at a temperature of 300℃ for 60 minutes, with argon gas protection during the tempering process.

[0044] Among them, see the standard processing mold. Figure 2 As shown, the processing mold includes a tempering and shaping upper mold 8, a tempering and shaping lower mold 9, a screw 12, and a nut 13.

[0045] The upper tempering and shaping mold 8 and the lower tempering and shaping mold 9 are arranged opposite each other, forming a shaping cavity mold 14 when the molds are closed. The upper tempering and shaping mold 8 has a first screw hole 10, and the lower tempering and shaping mold 9 has a second screw hole 11. The bottom of the lower tempering and shaping mold 9 also has a stepped countersunk hole 15, and the nut 13 has a third screw hole 16. During assembly, the screw 12 is sleeved on the second screw hole 11 of the lower tempering and shaping mold 9. The stepped head of the screw 12 is embedded in the stepped countersunk hole 15 on the lower tempering and shaping mold 9. The outer side wall of the screw 12 is fitted with the inner side wall of the upper tempering and shaping mold 8 and the lower tempering and shaping mold 9 with a clearance fit, so that the screw 12 can move freely up and down along the axial direction. However, when moving upward, it will be restricted by the stepped countersunk hole 15 to prevent it from dislodging from the lower tempering and shaping mold 9 during the upward movement. The workpiece is fitted into the shaping cavity mold 14. The first screw hole 10 of the tempering and shaping upper mold 8 aligns with the corresponding screw 12 along the crests and troughs of the wave before closing the mold. The third screw hole 16 of the nut 13 rotates along the thread to abut against the tempering and shaping upper mold 8. The height to which the nut 13 is screwed out controls the number of workpieces processed by the mold at one time, thereby fixing the height of the workpiece. After the mold is closed and fixed, it is placed in the furnace for tempering to fix the height of the wave spring and improve the accuracy of the height difference of each wave. In this processing mold, the screw 12 and the nut 13 serve to fix the workpiece during the upper and lower mold closing and opening, improving the accuracy of each wave in the workpiece processing.

[0046] S5. Inspection and Warehousing: After inspecting the wave height difference and hardness of the single-layer wave springs, they are put into storage.

[0047] Example 2

[0048] Referring to Example 1, the difference is that in step S2 of this example, the pressure is set to 2.0 MPa for forming; in step S3, the quenching temperature is 870°C; and in step S4, the tempering temperature is 320°C.

[0049] The remaining steps are the same as in Example 1.

[0050] Example 3

[0051] Referring to Example 1, the difference is that in step S2 of this example, the pressure is set to 2.2 MPa for forming; in step S3, the quenching temperature is 880°C; and in step S4, the tempering temperature is 340°C.

[0052] The remaining steps are the same as in Example 1.

[0053] Performance testing

[0054] Figure 3 The image shows a single-layer wave spring manufactured according to Example 1.

[0055] Figure 4 This is a schematic diagram of a single-layer wave spring.

[0056] Hardness testing: Using a Vickers hardness tester, the hardness of the single-layer wave spring manufactured in Example 1 reached 450 HV. The hardness of the single-layer wave spring manufactured in Example 2 reached 443 HV, and the hardness of the single-layer wave spring manufactured in Example 3 reached 446 HV.

[0057] Wave height difference measurement: Place the single-layer wave spring flat on a platform with secondary precision, and measure the highest point of the wave spring using a vernier depth gauge or special gauge with a graduation value less than or equal to 0.02 mm. Calculate the range of the three wave heights. After the above steps, the wave height difference of the single-layer wave springs manufactured in Examples 1-3 was found to be less than 0.1 mm.

[0058] Elastic force measurement: The elastic force was measured when the compression dimension was 2.3. The elastic force of the single-layer wave springs manufactured in Examples 1-3 was measured to be 35±3N.

[0059] Stability of spring force: The spring was compressed to its limit size, held for 2 seconds and then released. This was repeated 5 times. The spring force of the single-layer wave springs manufactured in Examples 1-3 was measured to be less than 1N.

[0060] The detailed descriptions listed above are merely specific illustrations of feasible embodiments of the present invention and are not intended to limit the scope of protection of the present invention. All equivalent embodiments or modifications made without departing from the spirit of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for manufacturing a single-layer wave spring, characterized in that: Includes the following steps: S1. Wire EDM: Cutting sheet metal into circular rings; S2. Pressure forming of the cut workpiece: Place the ring-shaped piece prepared in S1 into the processing mold, and use a press to slowly press and form it, with the pressure set at 1.8-2.2 MPa; S3. Quench the formed workpiece: the quenching temperature is 860-880℃, and the quenching medium is oil; S4. Tempering the quenched workpiece: Place the workpiece in a shaping mold for tempering at a temperature of 300-420℃, and use inert gas protection during the heat preservation process.

2. The method for manufacturing a single-layer wave spring according to claim 1, characterized in that: It also includes S5. Inspection and warehousing: After inspecting the wave height difference and hardness of the single-layer wave spring, it is put into storage.

3. The method for manufacturing a single-layer wave spring according to claim 1, characterized in that: In S2, the deformation process takes 1-2 seconds, and the pressure holding time is 2-3 seconds.

4. The method for manufacturing a single-layer wave spring according to claim 1, characterized in that: In step S3, the quenching and holding time is 40-60 minutes.

5. The method for manufacturing a single-layer wave spring according to claim 1, characterized in that: In step S4, the tempering and heat preservation time is 60-80 minutes.

6. The method for manufacturing a single-layer wave spring according to claim 1, characterized in that: The inert gas in S4 is argon.

7. A processing mold used in the manufacturing method of a single-layer wave spring as described in any one of claims 1-6, characterized in that: The processing mold includes a pressure-reducing processing mold, which includes a pressure-reducing upper mold (1) and a pressure-reducing lower mold (2) arranged opposite to each other. The pressure-reducing upper mold (1) and the pressure-reducing lower mold (2) form a cavity mold when the mold is closed. The pressure-reducing upper mold (1) and the pressure-reducing lower mold (2) are respectively provided with a first guide hole (6) and a second guide hole (7). A guide post (4) is inserted into the first guide hole (11) and the second guide hole (12). A limit ring (3) is sleeved on the outer side wall of the upper end of the pressure-reducing lower mold (2). A part removal groove (5) is opened on the limit ring (3).

8. The processing mold used in the manufacturing method of a single-layer wave spring according to claim 1, characterized in that: The limiting ring (3) and the pressure-reducing lower mold (2) are installed with a clearance fit.

9. The processing mold used in the manufacturing method of a single-layer wave spring according to claim 1, characterized in that: The processing mold also includes a tempering and shaping processing mold, which includes an upper tempering and shaping mold (8) and a lower tempering and shaping mold (9) arranged opposite to each other. When the upper tempering and shaping mold (8) and the lower tempering and shaping mold (9) are closed, a shaping cavity mold (14) is formed. The upper tempering and shaping mold (8) and the lower tempering and shaping mold (9) are respectively provided with a first screw hole (10) and a second screw hole (11). After the screw (12) passes through the first screw hole (10) and the second screw hole (11), its head extends to the top of the upper tempering and shaping mold (8). A nut (13) is threaded onto the threaded section of the screw (12) located above the upper tempering and shaping mold (8).

10. The processing mold used in the manufacturing method of a single-layer wave spring according to claim 9, characterized in that: The bottom of the tempering and shaping lower mold (9) is provided with a stepped countersunk hole (15), and the cap structure at the end of the screw (12) is embedded in the stepped countersunk hole (15).

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