Special tool for quenching duplicate gear shaft and quenching deformation control method

Abstract

The invention provides a special tool for quenching a duplicate gear shaft and a quenching deformation control method. The special tool for quenching comprises a base (1), a pressing ring (2), a centering sleeve (3), a mandrel (4) and a pressing head (5), a centering sleeve (3) is arranged in the center of the base (1); the bottom shaft diameter of the duplicate gear shaft is placed in a centering sleeve (3); the mandrel (4) is arranged in the internal spline of the duplicate gear shaft; the pressing ring (2) and the pressing head (5) are connected to a reducing sleeve at the top of a press, during quenching, the bottom end face of the pressing ring (2) is in contact with the upper end face of a large tooth web of the duplicate gear shaft, and the bottom end face of the pressing head (5) is in contact with the top shaft diameter end face of the duplicate gear shaft. The quenching deformation control effect of the internal spline thin web and the duplicate gear shaft is obvious, web warping and shaft shoulder deformation out-of-tolerance after heat treatment of parts can be effectively avoided, and the good shape correcting effect is achieved.

Description

Technical Field

[0001] The invention belongs to the field of quenching tooling and deformation control of gear shaft parts, and in particular relates to a special tooling for quenching a double gear shaft and a quenching deformation control method. Background Art

[0002] The aviation product involves a 16Cr3NiWMoVNbE steel carburized gear shaft, which has a double-tooth structure, such as Figure 1 As shown, the inner hole has an internal spline, the large web tooth top circle diameter is φ129.2-0.05mm, the web wall thickness is 10.625±0.02mm, the small web tooth top circle diameter is φ101.4-0.05mm, the web wall thickness is 15.35±0.02mm. Due to its process design requirements, the double teeth of the part need to be carburized, high-temperature tempering, cyaniding, quenching, ice cooling and tempering and other heat treatments. Due to the special structure of its double teeth, after quenching, the internal spline and web warping of the part and the dimensional deformation of the large web to the shaft diameter step (shoulder) are out of tolerance. The subsequent dimensional repair and correction through cold process cannot be carried out, resulting in the scrapping of batch parts.

[0003] To meet the requirements of subsequent cold processing, the carburizing process uses a press quenching tool adapted to the Gleason 537 quenching press to control quenching deformation. In the past, for gear shafts with single webs, dimensional deformation was directly or indirectly controlled by applying pressure to the entire web through free quenching or press quenching tooling. However, for duplex gears, it is impossible to control the web warping and shoulder dimensions through press quenching by applying pressure to the entire web. After quenching, the ovality and taper deformation of the external teeth are seriously out of tolerance, and the dimensional deformation of the internal spline cannot meet the requirements of subsequent cold processing. Summary of the Invention

[0004] The purpose of the present invention is to provide a special tooling for quenching a duplex gear shaft and a method for controlling quenching deformation. The method has obvious effect on controlling the quenching deformation of the thin web of the internal spline and the duplex gear shaft, can effectively avoid the web warping and excessive deformation of the shoulder after the parts are heat treated, and has a good shape correction effect.

[0005] The first aspect of the present invention provides a special tool for quenching a double gear shaft, comprising: a base 1, a pressure ring 2, a centering sleeve 3, a core shaft 4 and a pressure head 5; The base 1 is set on the bottom of the press. A through hole is set in the center of the base 1, and a centering sleeve 3 is set in the through hole. The bottom shaft diameter of the double gear shaft is placed in the centering sleeve 3. The top end surface of the base 1 is used to support the bottom surface of the large tooth web of the double gear shaft. The core shaft 4 is arranged in the internal spline of the duplex gear shaft to support the internal spline tooth top circle; The pressure ring 2 and the pressure head 5 are connected to the adapter sleeve on the top of the press machine. The inner diameter of the pressure ring 2 is larger than the addendum diameter of the small tooth web of the duplex gear shaft and smaller than the addendum diameter of the large tooth web of the duplex gear shaft. The bottom end surface of the pressure head 5 is provided with a blind hole, and the blind hole and the core shaft 4 are matched with a large clearance; During quenching, the bottom end surface of the pressure ring 2 contacts the upper end surface of the large tooth web of the duplex gear shaft, and the bottom end surface of the pressure head 5 contacts the top shaft diameter end surface of the duplex gear shaft.

[0006] Optionally, a washer is provided between the top end surface of the base 1 and the bottom surface of the large tooth web of the duplex gear shaft.

[0007] A second aspect of the present invention provides a method for controlling deformation during quenching of a duplex gear shaft, using any of the dedicated tooling for quenching a duplex gear shaft described in the first aspect, the method comprising: S1. Pre-process the duplex gear shaft; S2. Insert the large tooth web of the duplex gear shaft upward into a furnace and carburize it in a controlled atmosphere furnace. Carburize at a temperature of (920±10)°C and a carbon potential of (1.2±0.05)%C during the intense carburization phase. Cool the furnace to (840±20)°C and a carbon potential of (0.95±0.05)%C. Hold for (20±10) minutes. Cool in a protective atmosphere. S3. After controlled atmosphere carburizing, the duplex gear shaft is subjected to high-temperature tempering at a temperature of (680±10)°C for (330±30) min, with air cooling. S4. After high temperature tempering, the duplex gear shaft is subjected to copper sandblasting treatment; S5. Copper-plating the duplex gear shaft after the copper sandblasting process except for the internal spline area; S6. Insert the large tooth web of the duplex gear shaft upward into the furnace and place it in a controlled atmosphere furnace for cyanidation. The cyanidation temperature is (840±10)°C, the carbon potential in the strong permeation section is (1.0±0.05)%C, and the temperature is lowered to a holding time of (50±20) min. The ammonia flow rate is (400±100) L / h, and the cooling method is protective atmosphere cooling. S7. After the cyaniding treatment, the duplex gear shaft is subjected to high-temperature tempering treatment at a high-temperature holding temperature of (680±10)°C for (330±30) min, with air cooling. S8. The duplex gear shaft is subjected to copper sandblasting after high temperature tempering; S9. The duplex gear shaft is copper-plated after the copper sandblasting process; S10. The bottom diameter of the double gear shaft is placed in the centering sleeve 3, and the mandrel 4 is provided in the inner spline of the double gear shaft; Control the pressure ring 2 and the pressure head 5 on the top of the press to move downward for quenching treatment. The quenching and holding temperature is (910±10)℃, the time is (70±10)min, and the cooling method is oil cooling; ice cooling is performed within 2h after quenching. S11. Cryogenically treat the multi-zone carburized duplex gear shaft after quenching treatment at a temperature of (-75±10)°C for (2.5±0.5)h, air-cooling, and tempering within 2h after cryogenic treatment. S12. Perform low-temperature tempering on the cryogenically treated multi-zone carburized duplex gear shaft at a temperature of (200 ± 10)°C for (3.5 ± 0.5) h, with air cooling. S13. The duplex gear shaft after low temperature tempering is subjected to copper sandblasting treatment; S14. Dehydrogenate the duplex gear shaft after copper removal at a temperature of (140±10)°C for (5.5±0.5) h, and air cool.

[0008] Optionally, before the strong permeation stage of S2 and / or S6, the method includes: The carbon potential was controlled at (0.35)%C and kept warm for (35) min.

[0009] Optionally, in S10, the quenching holding temperature is (910)°C, the holding time is (70) min, the reference carbon potential is (0.5)%C, the quenching oil temperature is (68)°C, and the quenching cooling time is (300) s.

[0010] Optionally, in S10, the pressure setting value of the press ring (2) is 400 psi, and the pressure setting value of the pressure head (5) is 100 psi.

[0011] Optionally, pre-process the duplex gear shaft, including: The carburized surface of the duplex gear shaft is partially copper plated for protection and sand blasted.

[0012] Optionally, S11 includes: Within 2 hours after quenching, the multi-zone carburized duplex gear shaft is cryogenically treated.

[0013] Optionally, S12 includes: Within 2 hours after cryogenic treatment, the multi-zone carburized duplex gear shaft is subjected to low-temperature tempering treatment.

[0014] Optionally, S14 includes: Within 4 hours after copper removal, the duplex gear shaft shall be dehydrogenated.

[0015] The present invention provides a special tooling for quenching a duplex gear shaft and a method for controlling quenching deformation, utilizing a "weight-avoiding, constraint-reducing" approach to perform carburizing and quenching furnace loading. Through the "local press quenching, comprehensive control" method, the internal splines are supported by a core shaft to control deformation of the internal splines; upper and lower dies are used to perform local press quenching on the large-diameter thin web to control warping deformation; and a center pressure head is used to apply pressure to the top of the shaft diameter to control the shaft shoulder size, thereby achieving a comprehensive deformation control effect. The present invention effectively controls the heat treatment deformation of the internal spline duplex gear shaft and provides a theoretical basis for carburizing and quenching deformation control of other similar structural parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural diagram of a double gear shaft; Figure 2 A schematic diagram of the structure of the special tooling for quenching the duplex gear shaft provided by the present invention; Description of reference numerals: 1—base; 2—pressure ring; 3—Centering sleeve; 4—mandrel; 5—Indenter; 6—Washer. DETAILED DESCRIPTION

[0017] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative work are within the scope of protection of the present invention.

[0018] The features and illustrative embodiments of various aspects of the present invention will be described in detail below. In the detailed description below, many specific details are proposed in order to provide a comprehensive understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention can be implemented without the need for some of these specific details. The following description of the embodiments is merely intended to provide a better understanding of the present invention by illustrating examples of the present invention. The present invention is in no way limited to any specific arrangement and method proposed below, but rather encompasses any improvements, replacements, and modifications to structures, methods, and devices without departing from the spirit of the present invention. In the accompanying drawings and the following description, well-known structures and techniques are not shown to avoid unnecessary ambiguity in the present invention.

[0019] In the description of the present invention, it should be noted that the directions or positional relationships indicated by terms such as "center," "up," "down," "left," "right," "vertical," "horizontal," "inside," and "outside" are based on the directions or positional relationships described in the accompanying drawings and are intended only to facilitate and simplify the description of the present invention and should not be construed as limiting the present invention. Furthermore, the use of ordinal numbers (e.g., "first and second," etc.) is intended to distinguish between objects and is not limited to this order, and should not be construed as indicating or implying relative importance.

[0020] In the description of the present invention, it should be noted that, unless otherwise specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly, and may refer to direct connection or indirect connection through an intermediary. Those skilled in the art will understand the specific meanings of these terms in the present invention.

[0021] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other, and the embodiments can refer to and quote each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0022] The present invention will be described in further detail below with reference to the embodiments and drawings, but the embodiments of the present invention are not limited thereto.

[0023] like Figure 2 As shown, the present invention provides a special tool for quenching a double gear shaft, comprising: a base 1, a pressure ring 2, a centering sleeve 3, a core shaft 4 and a pressure head 5; The base 1 is set on the bottom of the press. A through hole is set in the center of the base 1, and a centering sleeve 3 is set in the through hole. The bottom shaft diameter of the double gear shaft is placed in the centering sleeve 3. The top end surface of the base 1 is used to support the bottom surface of the large tooth web of the double gear shaft. The core shaft 4 is arranged in the internal spline of the duplex gear shaft to support the internal spline tooth top circle; The pressure ring 2 and the pressure head 5 are connected to the adapter sleeve on the top of the press machine. The inner diameter of the pressure ring 2 is larger than the addendum diameter of the small tooth web of the duplex gear shaft and smaller than the addendum diameter of the large tooth web of the duplex gear shaft. The bottom end surface of the pressure head 5 is provided with a blind hole, and the blind hole and the core shaft 4 are matched with a large clearance; During quenching, the bottom end surface of the pressure ring 2 contacts the upper end surface of the large tooth web of the duplex gear shaft, and the bottom end surface of the pressure head 5 contacts the top shaft diameter end surface of the duplex gear shaft.

[0024] Optionally, a washer is provided between the top end surface of the base 1 and the bottom surface of the large tooth web of the duplex gear shaft.

[0025] In an exemplary embodiment, a gasket 6 is provided between the top of the pressure head 5 and the adapter sleeve.

[0026] The present invention provides a special tool for quenching an ultra-thin web double gear shaft and a method for accurately controlling shaft shoulder deformation, comprising the following steps: S1. Pre-treat carburized gears; S2. Carburize the gear in a controlled atmosphere furnace at a temperature of (920±10)°C and a carbon potential of (1.2±0.05)%C in the intensive carburizing stage. Cool the gear to (840±20)°C with a carbon potential of (0.95±0.05)%C. Hold the temperature for (20±10) min. Cool the gear in a protective atmosphere. S3. The gear is subjected to high temperature tempering after controlled atmosphere carburizing treatment; S4. The gear shaft is subjected to copper sandblasting after high temperature tempering; S5. The gear shaft is partially copper plated after the copper sandblasting process; S6. Place the gear in a cyanidation process at a temperature of (840±10)°C, a carbon potential of (1.0±0.05)%C in the strong penetration section, and cool the gear to a holding temperature of (50±20) min with an ammonia flow rate of (400±100) L / h. Cool the gear in a protective atmosphere. S7. Perform high-temperature tempering on the cyanided gear at a holding temperature of (680±10)°C for (330±30) min, using air cooling. S8. The gear shaft is subjected to copper sandblasting after high temperature tempering; S9. The gear shaft is copper plated after the copper sandblasting process; S10. Quench the entire copper-plated gear shaft at a quenching and holding temperature of (910±10)°C for (70±10) min, using oil cooling; ice cooling is performed within 2 h after quenching. S11. Cryogenically treat the multi-zone carburized gear after quenching treatment at a temperature of (-75±10)°C for (2.5±0.5)h, air-cooling, and tempering within 2h after cryogenic treatment. S12. Perform low-temperature tempering on the cryogenically treated multi-zone carburized gear at a temperature of (200 ± 10)°C for (3.5 ± 0.5) h, with air cooling. S13. The carburized gear after low temperature tempering is subjected to copper sandblasting treatment; S14. Dehydrogenate the carburized gear after copper removal at a temperature of (140±10)°C for (5.5±0.5) h, and air cool.

[0027] In a specific embodiment: The intermediate gear shaft of a booster pump made of 16Cr3NiWMoVNbE material, the schematic diagram of the parts is attached Figure 1For a duplex gear structure, the tooth carburizing depth is required to be 0.75-0.9mm (measured to HV550). The tooth top allows for 0.75-1.55mm, and the tooth root allows for 0.6-0.9mm. After carburizing, the large-diameter web warpage is required to be ≤0.15mm. The shaft shoulder dimensions are required to be 37.125.7±0.08mm, and the internal spline roller dimension is 19.541+0.041 (φ1.732).

[0028] The dedicated tooling for quenching the ultra-thin web duplex gear shaft and the precise control method for shoulder deformation of this embodiment specifically include the following steps: (1) All areas except the gear tooth surface are copper-plated for protection, with a copper layer thickness of 0.03 mm; (2) Use a sand blasting machine to clean the carburized surface of the parts. The sand blasting pressure is 0.2 MPa. Carburizing should be carried out within 1 hour after sand blasting. (3) Carburizing: carburizing temperature is (920)℃, carbon potential of stage I is (0.35)%C, holding time is (35)min, carbon potential of stage II is (1.20)%C, holding time is (120)min, cooling to (840)℃, carbon potential is (0.95)%C, holding time is (20)min, cooling method is protective atmosphere cooling, and the large diameter web of the part is inserted into the furnace upward; (4) Use protective atmosphere furnace for high temperature tempering, keep the temperature at 680℃ for 330min, and use air cooling for cooling; (5) Remove the copper layer and oxide scale on the surface of parts; (6) All parts except the internal splines are copper-plated, with a copper layer thickness of 0.01 mm; (7) All parts except the internal splines are copper-plated, with a copper layer thickness of 0.01 mm; (8) Cyanidation: The cyanidation temperature is (840) °C, the carbon potential of stage I is (0.35)%C, the holding time is (35) min, the carbon potential of stage II is (1.0)%C, the holding time is (50) min, the cooling method is air cooling, and the part is inserted into the furnace with the large diameter web facing upwards; (9) Use protective atmosphere furnace for high temperature tempering, keep the temperature at 680℃ for 330min, and use air cooling for cooling; (10) Remove the copper layer on the surface of the parts and prohibit sand blowing on the splines; The parts are quenched using a RDES-230CN rotary hearth furnace for heat preservation and a Gleason 537 pressure quenching machine with a dedicated pressure quenching fixture for oil cooling. The quenching and holding temperature is 910°C, the holding time is 70 minutes, the reference carbon potential is 0.5%C, the quenching oil temperature is 68°C, and the quenching cooling time is 300 seconds. The tooling structure is shown in the attached figure. Figure 2, 15 seconds after the part is heated, it is transferred to the tooling of the pressure quenching machine. The pressure setting value of the machine outer ring (pressure ring 2) is 400psi, and the pressure setting value of the expander (pressure head 5) is 100psi.

[0029] After zero heating out of the furnace, place the part with the spline facing upward in the press positioning sleeve to center the part, then put the mandrel into the internal spline to support the internal spline tooth top circle, transfer the part and the mandrel into the press for quenching, the press head 5 presses the shaft end under the pulse pressure applied by the machine tool, and the press ring 2 and the base 1 press quench the external teeth of the part; (11) Deep cooling at -75℃ for 2.5h, and tempering within 2h after deep cooling; (12) Tempering at 200℃ for 3.5h, air cooling; (13) Remove the copper layer and oxide scale on the surface of parts; (14) Dehydrogenation at 140 °C for 5.5 h, air cooling; (15) Dimension inspection.

[0030] After the end, the measured values ​​are as follows: 1. The carburizing depth of the tooth part is 0.82mm (measured to HV550), the carburizing layer depth at the tooth top is 1.15mm, and the carburizing layer depth at the tooth root is 0.75mm; 2. The large diameter web warpage is 0.05mm, and the shoulder size is 37.15~37.18mm.

[0031] 3. The dimension between the internal spline rollers is 19.55~19.57 (φ1.732).

[0032] The conclusion is qualified.

[0033] The above description is merely a specific implementation case of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements and improvements within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A special tool for quenching double gear shafts, characterized in that: include: Base (1), pressure ring (2), centering sleeve (3), core shaft (4) and pressure head (5); The base (1) is arranged on the bottom of the press, a through hole is arranged in the center of the base (1), and a centering sleeve (3) is arranged in the through hole; the bottom shaft diameter of the double gear shaft is placed in the centering sleeve (3); the top end surface of the base (1) is used to support the bottom surface of the large tooth web of the double gear shaft; The core shaft (4) is arranged in the internal spline of the duplex gear shaft to support the internal spline tooth top circle; The pressure ring (2) and the pressure head (5) are connected to the adapter sleeve on the top of the press machine, and the inner diameter of the pressure ring (2) is larger than the diameter of the tooth top circle of the small tooth web of the duplex gear shaft and smaller than the diameter of the tooth top circle of the large tooth web of the duplex gear shaft; The bottom end surface of the pressure head (5) is provided with a blind hole, and the blind hole and the core shaft (4) are matched with a large clearance; During quenching, the bottom end face of the pressure ring (2) contacts the upper end face of the large tooth web of the duplex gear shaft, and the bottom end face of the pressure head (5) contacts the top shaft diameter end face of the duplex gear shaft.

2. The special tooling for quenching the double gear shaft according to claim 1, characterized in that: A washer is provided between the top end surface of the base (1) and the bottom surface of the large tooth web of the duplex gear shaft.

3. A method for controlling quenching deformation of a double gear shaft, characterized in that: Using the special tooling for quenching the double gear shaft according to claim 1 or 2, the method comprises: S1. Pre-process the duplex gear shaft; S2. Insert the large tooth web of the duplex gear shaft upward into a furnace and carburize it in a controlled atmosphere furnace. Carburize at a temperature of (920±10)°C and a carbon potential of (1.2±0.05)%C during the intense carburization phase. Cool the furnace to (840±20)°C and a carbon potential of (0.95±0.05)%C. Hold for (20±10) minutes. Cool in a protective atmosphere. S3. After the controlled atmosphere carburizing treatment, the duplex gear shaft is subjected to high temperature tempering treatment; S4. After high temperature tempering, the duplex gear shaft is subjected to copper sandblasting treatment; S5. Copper-plating the duplex gear shaft after the copper sandblasting process except for the internal spline area; S6. Insert the large tooth web of the duplex gear shaft upward into the furnace and place it in a controlled atmosphere furnace for cyanidation. The cyanidation temperature is (840±10)°C, the carbon potential in the strong permeation section is (1.0±0.05)%C, and the temperature is lowered to a holding time of (50±20) min. The ammonia flow rate is (400±100) L / h, and the cooling method is protective atmosphere cooling. S7. The double gear shaft after cyaniding is subjected to high temperature tempering treatment; S8. The duplex gear shaft is subjected to copper sandblasting after high temperature tempering; S9. The duplex gear shaft is copper-plated after the copper sandblasting process; S10. The bottom shaft diameter of the double gear shaft is placed in the centering sleeve (3), and the core shaft (4) is set in the inner spline of the double gear shaft; Controlling the pressing ring (2) and the pressing head (5) on the top of the press to move downwards for quenching treatment; S11. The multi-zone carburized duplex gear shaft after quenching is cryogenically treated; S12. The multi-zone carburized duplex gear shaft after cryogenic treatment is subjected to low-temperature tempering treatment; S13. The duplex gear shaft after low temperature tempering is subjected to copper sandblasting treatment; S14. Dehydrogenate the duplex gear shaft after copper removal.

4. The method for controlling quenching deformation of a duplex gear shaft according to claim 3, characterized in that: Before the strong permeation stage of S2 and / or S6, the method includes: The carbon potential was controlled at (0.35)%C and kept warm for (35) min.

5. The method for controlling quenching deformation of a duplex gear shaft according to claim 3, characterized in that: In S10, the quenching holding temperature is (910) °C, the holding time is (70) min, the reference carbon potential is (0.5)%C, the quenching oil temperature is (68) °C, and the quenching cooling time is (300) s.

6. The method for controlling quenching deformation of a duplex gear shaft according to claim 3, characterized in that: In S10, the pressure setting value of the press ring (2) is 400 psi, and the pressure setting value of the pressure head (5) is 100 psi.

7. The method for controlling quenching deformation of a duplex gear shaft according to claim 3, wherein: Pre-processing of the duplex gear shaft, including: The carburized surface of the duplex gear shaft is partially copper plated for protection and sand blasted.

8. The method for controlling quenching deformation of a duplex gear shaft according to claim 3, characterized in that: The S11 includes: Within 2 hours after quenching, the multi-zone carburized duplex gear shaft is cryogenically treated.

9. The method for controlling quenching deformation of a duplex gear shaft according to claim 3, characterized in that: S12 includes: Within 2 hours after cryogenic treatment, the multi-zone carburized duplex gear shaft is subjected to low-temperature tempering treatment.

10. The method for controlling quenching deformation of a duplex gear shaft according to claim 3, characterized in that: S14 includes: Within 4 hours after copper removal, the duplex gear shaft shall be dehydrogenated.

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