Axial and radial bidirectional limiting quenching die based on phase change heat compensation

Abstract

The application discloses a shaft-diameter bidirectional limiting quenching die based on phase change heat compensation, belongs to the technical field of gear part quenching heat treatment die, and is designed for the problems of thin-web wave distortion, inner hole shrinkage and end face warping of thin-web gears (especially 9310 steel materials) which are easily caused by the action of organizational stress and thermal stress in the heat treatment process. The pressure quenching die can be axially and radially limited and can compensate temperature. The pressure quenching die is composed of a multi-hole convection enhanced axial outer pressure ring, an axial limiting inner pressure ring, a multi-stage compression radial limiting multi-claw support body, an axial driving variable diameter mandrel, a lower die support seat, a lower die base and a positioning pin assembly. The thin-web gear is heated to quenching temperature and kept for a period of time, the gear is transferred from the heating furnace and sleeved into the pressure quenching die by using a special extraction aid, the press is started, the press and the die jointly act, the thin-web gear is deformed in the shaft-diameter bidirectional direction, and the thin-web gear part meeting the finishing requirement is obtained. The technical problems of controlling the heat treatment deformation of gear parts and single direction limiting are solved.

Description

Technical Field

[0001] This invention belongs to the technical field of quenching heat treatment molds for gear parts, and mainly relates to a shaft diameter bidirectional limiting quenching mold based on phase transformation heat compensation. Background Technology

[0002] In the mechanical transmission system of aero-engines, aero-gears occupy a central position and are crucial for ensuring the engine's long service life and high reliability. 9310 steel, as a high-performance carburizing gear steel, is widely used in the manufacture of thin-web gears. To meet the service requirements of aero-gears under extremely complex operating conditions, 9310 steel thin-web gears typically undergo carburizing and quenching heat treatment, thereby significantly improving the load-bearing capacity and fatigue resistance of the tooth surface, ensuring the efficient and stable operation of the transmission system.

[0003] Thin-web gears have obvious discontinuous geometric features and thin-walled structures. In the traditional carburizing process, the volume expansion of the carburized layer during the martensitic transformation is inconsistent with the transformation of the core structure, which leads to the shrinkage of the gear inner hole, uneven distribution of quenching oil on the gear surface, and differences in cooling rate in the radial direction of the gear. This causes the gear end face to warp. The gear web is thin and has a large thickness difference with other areas, making it very easy to become unstable and twisted under the action of thermo-mechanical coupling, resulting in wave distortion of the gear web.

[0004] Traditional gear quenching dies typically apply rigid or flexible constraints to critical gear components to control deformation, employing simple conical expansion or pressure plate clamping. These conventional dies cannot dynamically compensate for the volume shrinkage of the gear during cooling, achieving only single-dimensional constraint and failing to provide coordinated support for complex hubs, inner rings, and rims. Therefore, developing a shaft diameter bidirectional constraint quenching die based on phase change heat compensation is of practical significance. Summary of the Invention

[0005] The present invention aims to provide a shaft diameter bidirectional limiting quenching mold based on phase change heat compensation. During the quenching process, the deformation of thin-web gears is controlled by dynamic compensation of intelligent phase change materials and bidirectional limiting of shaft diameter.

[0006] The technical solution of the present invention is as follows:

[0007] A shaft diameter bidirectional limiting quenching mold based on phase change heat compensation includes: a porous convection-enhanced axial outer pressure ring 1, an axial limiting inner pressure ring 2, a multi-stage clamping radial limiting octagonal support body 3, an axially driven variable diameter mandrel 4, a lower mold support seat 5, a lower mold base 6, a positioning pin assembly 7, a variable diameter slide groove I, and a variable cross-section Laval type oil drain groove II, characterized in that: The multi-stage pressing radial limiting octagonal support body 3 adopts a radial cantilever layout. Its characteristic is that the support body is arranged symmetrically in a radial pattern around the axial drive variable diameter spindle 4, with each support unit independently embedded in the guide hole of the axial limiting inner pressure ring 2. The multi-stage pressing radial limiting multi-claw support body 3, through the coupling of axial mechanical stroke drive and radial thermal stress compensation, constructs a full-process adaptive constraint system to ensure that the thin-web gear remains under a fixed displacement-pressure self-compensating support function throughout the drastic phase transformation process. The lower mold support 5 adopts an interlocking spiral pressure-bearing structure, specifically including: a multi-functional end face pressure-bearing ring 5-1, a hub pressure-bearing ring 5-2, and a radially segmented expansion mandrel 5-3. The key feature is that the contact surface between the multi-functional end face pressure-bearing ring 5-1 and the hub pressure-bearing ring 5-2 is designed with a large helix angle thread; the upper mating surface of the multi-functional end face pressure-bearing ring 5-1 is provided with an annular support surface and a raised constraint ring for positioning the gear; the radially segmented expansion mandrel 5-3 consists of six strip-shaped expansion wedges arranged in a circumferential array inside the hub pressure-bearing ring 5-2, and its inner wall engages with the expansion drive ball head 4-1 in a wedge-shaped configuration.

[0008] Furthermore, the thin-web gear is placed in a carburizing furnace for high-temperature carburizing, establishing a preset surface carbon concentration gradient and carburizing layer depth at a temperature of 930℃. The carburized gear is then transferred to a heating furnace and held at 820±10℃ for 80±10 minutes to ensure sufficient homogenization of the matrix structure.

[0009] Furthermore, the lower mold base 6 is connected to the inner mold of the quenching bed through the pre-set positioning pin assembly 7, and the oil inlet is connected to the fluid distribution interface of the quenching bed. A radial flow channel is set to facilitate the orderly entry of quenching oil into the circulating oil circuit.

[0010] Furthermore, the multifunctional end-face pressure ring 5-1 is nested in the wedge-shaped constraint boss structure of the lower mold base 6, and the oil inlet hole corresponds one-to-one with the oil inlet hole of the lower mold base 6. The multifunctional end-face pressure ring 5-1 is provided with 16 variable cross-section Laval-type oil drain grooves II on the side wall. The variable cross-section Laval-type oil drain grooves II apply the Venturi effect to accelerate the flow rate of quenching.

[0011] Furthermore, the radially segmented expansion mandrel 5-3 is formed by six identical strip-shaped expansion wedges surrounding the inner side of the hub bearing ring 5-2, and its outer surface is provided with an arc surface with the same curvature as the inner hole of the thin-web gear, which can ensure complete fit with the inner hole of the thin-web gear and avoid stress concentration.

[0012] Furthermore, the heat-insulated thin-web gear is moved into the quenching bed and precisely positioned by the annular support surface of the multifunctional end face bearing ring 5-1. Then, the inner mold of the quenching bed moves upward to send the radially segmented expansion mandrel into the inner hole of the thin-web gear.

[0013] Furthermore, the porous convection-enhanced axial external pressure ring 1 is connected to the external mold of the quenching machine through the specially designed positioning pin assembly 7, ensuring that the axis of the porous convection-enhanced axial external pressure ring 1 is highly coaxial with the machine tool spindle, and presses the gear rim under the push of the quenching machine tool spindle.

[0014] Furthermore, the upper part of the guide cone ring 2-1 of the axial limiting inner pressure ring 2 is connected to the spindle of the quenching bed through eight pre-set positioning pin holes 7. Under the push of the spindle, the gear hub is pressed. Then, the hub pressure ring 2-2 is nested in the inner wall of the guide cone ring 2-1 and positioned and installed through the threaded holes of the two components.

[0015] Furthermore, the porous convection-enhanced axial outer pressure ring 1 and the axial limiting inner pressure ring 2, driven by the spindle of the quenching bed, move downwards and press against the rim and hub of the thin-web gear respectively to perform axial limiting control.

[0016] Furthermore, the multi-stage pressing radial limiting octagonal support body 3 consists of eight multi-stage pressing radial single-claw support bodies installed in the guide hole of the guide cone ring 2-1. The spherical pair on the top is connected to the variable diameter slide groove I on the side of the axial drive variable diameter mandrel 4. The radial support slider 3-1 is threaded to the end of the spherical self-aligning push rod. The limiting groove of the thermal response compensator 3-2 is set in the center of the radial support slider 3-1. Then, the thermal response compensator 3-2 is installed in the limiting groove and connected to the limiting boss of the spherical self-aligning push rod 3-3.

[0017] Furthermore, the spindle of the quenching bed drives the axially driven variable diameter mandrel 4 to move up and down, and the spherical self-aligning push rod 3-3 generates radial displacement accordingly, realizing the variable diameter function, and supporting the radial support slider 3-1 to support the inner ring of the thin web gear for radial limit control.

[0018] Furthermore, the thermal response compensator 3-2 is made of a high thermal expansion coefficient material and has a constant pitch of 1.5 mm, a length of 10.5 mm, and a diameter of 5.5 mm. It has a two-way thermally induced phase change characteristic. When the temperature is high, the thermal response compensator 3-2 will expand and press against the limiting boss of the spherical self-aligning push rod 3-3 and the limiting groove of the radial support slider 3-1. The change in oil temperature in the quenching bed causes the thermal response compensator 3-2 to be tightened a second time, floating the inner ring of the support gear.

[0019] The beneficial effects of this invention are as follows:

[0020] 1. This invention dynamically compensates for the supporting force by utilizing the difference in the thermal expansion coefficient of intelligent phase change materials at different temperatures, enabling multi-level clamping methods and ensuring that the warping of the gear end face and the deformation of the web are within the required range.

[0021] 2. This invention can automatically adjust the gear support for inner rings of different diameters by moving the variable diameter mandrel up and down through the axial drive variable diameter slide groove, and has the characteristics of high adjustability and flexibility.

[0022] 3. This invention controls the deformation of thin-web gears by limiting the shaft diameter in both directions. The axial pressure ring and radial support slider in the upper mold and the bearing ring and segmented radial expansion mandrel in the lower mold work together to achieve bidirectional deformation control of the shaft diameter. Attached Figure Description

[0023] Figure 1 This is a cross-sectional view of a shaft diameter bidirectional limiting quenching mold tooling based on phase change heat compensation in this invention.

[0024] Figure 2 This is a schematic cross-sectional view of the thin-web pressure-quenched gear in this invention;

[0025] Figure 3 This is a diagram showing the arrangement of the multi-stage pressing radial limiting octagonal support body in this invention;

[0026] Figure 4 This is an isometric view of the multi-stage compression radial limiting support body in this invention;

[0027] Figure 5 This is a front view of the axially driven variable diameter mandrel in this invention;

[0028] Figure 6 This is a cross-sectional view of the lower mold support base in this invention.

[0029] The labels in the diagram are as follows:

[0030] 1. Porous convection-enhanced axial outer pressure ring; 2. Axial limiting inner pressure ring; 3. Multi-stage clamping radial limiting octagonal support; 4. Axial drive variable diameter mandrel; 5. Lower die support seat; 6. Lower die base; 7. Positioning pin assembly; 2-1. Guide cone ring; 2-2. Hub inner pressure ring; 3-1. Radial support slider; 3-2. Thermal response compensator; 3-3. Spherical self-aligning push rod; 4-1. Expansion drive ball head; 5-1. Multifunctional end face bearing ring; 5-2. Hub bearing ring; 5-3. Radial segmented expansion mandrel; Ⅰ. Variable diameter groove; Ⅱ. Variable cross-section Laval type oil drain groove. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be described more clearly and completely below with reference to the accompanying drawings.

[0032] like Figure 1 , 2 As shown, this example provides a shaft diameter bidirectional limiting quenching mold based on phase change heat compensation. The mold includes: a porous convection-enhanced axial outer pressure ring 1, an axial limiting inner pressure ring 2, a multi-stage clamping radial limiting octagonal support body 3, an axial drive variable diameter mandrel 4, a lower mold support seat 5, a lower mold base 6, a positioning pin assembly 7, a variable diameter slide groove I, and a variable cross-section Laval type oil drain groove II.

[0033] The porous convection-enhanced axial external pressure ring 1 and the axially limiting internal pressure ring 2 are respectively provided with positioning pins 7 on their outer circumferences. The porous convection-enhanced axial external pressure ring 1 and the axially limiting internal pressure ring 2 are respectively connected to the positioning threaded holes on the outer mold of the quenching press through the positioning pins 7. The porous convection-enhanced axial external pressure ring 1 is provided with a quenching medium circulation and drainage loop channel, and the contact area of ​​the gear end face is not less than 80%, ensuring that the gear is subjected to sufficient pressure, controlling the warping deformation of the end face, and controlling the deformation amount within 0.003mm.

[0034] The axial limiting inner pressure ring 2 adopts a nested structure. The hub inner pressure ring 2-1 is designed as a hollow tube structure. The upper part has 8 M6 threaded holes along the ring wall. The guide cone ring 2-1 and the hub pressure ring are installed through the positioning threaded holes. 8 through holes with a diameter of 6mm are designed on the side cone surface of the guide cone ring for installing the multi-stage pressing radial limiting octagonal support body 3. 8 positioning pins 7 are set on the top of the guide cone ring 2-1.

[0035] like Figure 3 As shown, the multi-stage pressing radial limiting octagonal support body 3 adopts a radial cantilever layout. The support body is arranged symmetrically in a radial pattern with the axial drive variable diameter mandrel 4 as the center. Each support unit is independently embedded in the guide hole of the axial limiting inner pressure ring 2, realizing the limiting control of the thin web gear in the radial direction and solving the problem of web deformation of the thin web gear during the quenching process.

[0036] The porous convection-enhanced axial external pressure ring 1, the axial limiting internal pressure ring 2, and the multi-stage pressing radial limiting octagonal support body 3 work together to achieve bidirectional deformation control of the shaft diameter, solving the limitation problem of single-direction deformation control.

[0037] like Figure 4As shown, the axial drive variable diameter mandrel 4 is designed as a variable diameter truncated cone in the middle, and eight variable diameter grooves are designed on the side of the variable diameter truncated cone. This is the core of the structure. These variable diameter grooves have an inclination angle of 155° relative to the axis. When the axial drive variable diameter mandrel 4 moves downward along the axis, the spherical self-aligning push rod moves in the variable diameter groove. Through the physical contact of the wedge surface, the axial force is decomposed into a huge radial component. The axial drive variable diameter mandrel 4 drives the multi-stage clamping radial limiting eight-claw support body 3 to internally clamp the inner ring of the thin-web gear, providing circumferential uniform rigid support for the thin-web gear.

[0038] The thermal response compensator in the multi-stage clamping radial limiting octagonal support 3 is made of nickel-titanium alloy with a high coefficient of thermal expansion. It is designed as a spring structure with a constant pitch of 1.5mm, a length of 10.5mm, and a diameter of 5.5mm. It is repeatedly trained to ensure its stability during operation.

[0039] During the pressure quenching process, the thermal response compensator 3-2 undergoes three stages. The first stage: after the hot gear is placed into the mold and the mold is closed, heat is rapidly conducted to the thermal response compensator 3-2 through the quenching oil, causing it to initially expand and eliminate mechanical gaps between the mold components. The second stage: as heat from the gear continues to be input into the quenching oil, the thermal response compensator 3-2 enters a high expansion rate range. Due to uneven heating, the thin-web gear begins to deform, but the dynamic support provided by the thermal response compensator 3-2 counteracts this tendency, ensuring that the gear web does not warp. The third stage: after entering the cooling stage, due to thermal contraction, the tension of the thermal response compensator 3-2 gradually decreases, preventing excessive thermal stress from causing cracking in the thin-web gear during the later stages of hardening.

[0040] The thermal response compensator in the multi-stage clamping radial limiting octagonal support 3 realizes the difference in thermal expansion coefficient of the phase change material at different temperatures to dynamically compensate for the support force, thus achieving the multi-stage clamping function.

[0041] like Figure 5 As shown, the lower mold support 5 adopts an interlocking spiral pressure-bearing structure. A stepped hole is machined at the center of the multi-functional end face pressure ring 5-1. A coaxial large helix angle internal thread is machined on the inner wall of the stepped hole. Sixteen variable cross-section Laval-type oil drain grooves are arranged in a circumferential array around the central axis on the side of the multi-functional end face pressure ring 5-1. The inner side of the variable cross-section Laval-type oil drain groove accelerates the flow rate of quenching oil, which solves the deformation problem caused by the large difference in cooling rate of thin web gears. A stepped positioning surface is provided at the top of the multi-functional end face pressure ring 5-1. In order to ensure its positioning accuracy, the surface roughness of the stepped positioning surface is Ra0.4.

[0042] The hub bearing ring 5-2 has an external thread with a pitch of 5mm machined at the bottom and a thickened bearing flange at the top. Under the action of the inner mold of the quenching bed, the hub bearing ring 5-2 converts the rotational motion into axial linear upward motion through the thread pair of the multi-functional end face bearing ring 5-1, which supports the hub of the thin-web gear and ensures the force balance between the outer circle of the gear and the hub.

[0043] The radially segmented expansion mandrel 5-3 is formed by six identical strip-shaped expansion wedges arranged inside the hub bearing ring 5-2. The inner surface of the hole formed by the strip-shaped expansion wedges has the same arc surface as the outer surface of the hemispherical expansion drive ball head 4-1, and the roughness is no greater than Ra0.4 to ensure fitting accuracy. A 5mm space is left between each strip-shaped expansion wedge to facilitate the flow of quenching oil, while also ensuring that the contact area with the gear inner hole is no less than 90%.

[0044] The lower die support 5 achieves bidirectional limit control of the shaft diameter through the combined action of the multi-functional end face bearing ring 5-1, the hub bearing ring 5-2, and the radially segmented expansion mandrel 5-3, working in conjunction with the upper die. The lower die support 5 accelerates the flow rate of quenching oil through the variable cross-section Laval-type oil drain groove II, reducing the wavy distortion caused by the large difference in cooling rate of the thin web.

[0045] The lower mold base 6 is connected to the positioning threaded hole on the inner mold of the quenching press through the positioning pin 7, and is fixed to the inner mold of the quenching press. The oil inlet and auxiliary flow channel at the bottom are connected to the quenching medium circulation cooling system of the quenching press.

[0046] The porous convection-enhanced axial outer pressure ring 1, the axial limiting inner pressure ring 2, the spherical self-aligning push rod 3-3, the radial support slider 3-1, the axial drive variable diameter mandrel 4, the lower mold support seat 5, and the lower mold base 6 are all made of GCr15 steel with a hardness of 58-62HRC.

[0047] A shaft diameter bidirectional limiting quenching mold based on phase change heat compensation includes the following steps:

[0048] Step 1: The inner mold of the quenching bed lifts the lower mold base, the lower mold support is fixed, and the thin-web gear is moved from the heating furnace to the quenching bed and placed on the first positioning surface of the multi-functional end face bearing ring.

[0049] Step 2: The quenching bed die drives the porous convection-enhanced axial external pressure ring downward to press against the thin-web gear rim;

[0050] Step 3: The hub bearing ring spirals upward, the hub end face of the thin-web gear engages with the second positioning surface of the hub bearing ring, and the radially segmented expansion mandrel is inserted into the gear's inner hole;

[0051] Step 4: The axial limiting inner pressure ring descends and presses against the gear hub, and drives the multi-stage pressing radial limiting eight-claw support body to press against the inner ring of the gear. The axially driven variable diameter mandrel presses against the support body to apply a fixed mechanical support force to the gear.

[0052] Step 5: The quenching bed is closed. The quenching oil flows into the quenching mold through the cooling circulation system. The quenching oil flows from the inside to the outside through the variable cross-section Laval-type oil discharge groove of the lower mold support.

[0053] Step 6: After the quenching of the thin-web gear is completed, the quenching oil flows out through the cooling circulation system, the mold is opened, and the thin-web gear is moved to the next process.

[0054] Obviously, the above specific embodiments are only used to illustrate the technical solution of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above specific embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific embodiments of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of the claims.

Claims

1. A shaft diameter bidirectional limiting quenching mold based on phase change heat compensation, comprising: The axial external pressure ring (1) with porous convection enhancement, the axial limiting internal pressure ring (2), the multi-stage clamping radial limiting octagonal support body (3), the axial drive variable diameter mandrel (4), the lower die support seat (5), the lower die base (6), the positioning pin assembly (7), the variable diameter slide groove (Ⅰ), and the variable cross-section Laval type oil drain groove (Ⅱ) are characterized by: The multi-stage pressing radial limiting octagonal support (3) adopts a radial cantilever layout. The support is arranged symmetrically in a radial pattern with the axial drive variable diameter spindle (4) as the center. Each support unit is independently embedded in the guide hole of the axial limiting inner pressure ring (2). The multi-stage pressing radial limiting octagonal support (3) constructs a full-process adaptive constraint system through the coupling of axial mechanical stroke drive and radial thermal stress compensation to ensure that the thin-web gear is always in a fixed displacement-pressure self-compensation support role during the violent phase transformation process. The lower mold support (5) adopts an interlocking spiral pressure bearing structure, specifically including: a multi-functional end face pressure bearing ring (5-1), a hub pressure bearing ring (5-2), and a radially segmented expansion mandrel (5-3). The contact surface between the multi-functional end face pressure bearing ring (5-1) and the hub pressure bearing ring (5-2) is designed with a large helix angle thread. The upper mating surface of the multi-functional end face pressure bearing ring (5-1) is provided with an annular support surface and a raised constraint ring for positioning the gear position. The radially segmented expansion mandrel (5-3) is installed inside the hub pressure bearing ring (5-2) by a circumferential array of 6 strip-shaped expansion wedges, and its inner wall is wedge-shapedly engaged with the expansion drive ball head (4-1).

2. The shaft diameter bidirectional limiting quenching mold based on phase change heat compensation according to claim 1, characterized in that: The porous convection-enhanced axial external pressure ring (1) has a circular hole hollow structure, and its side wall is provided with a radial convection-enhancing hole group arranged in a 360° circumferential array around the central axis. The bottom mating surface is provided with a semi-circular quenching medium circulation discharge circuit channel.

3. The shaft diameter bidirectional limiting quenching mold based on phase change heat compensation according to claim 1, characterized in that: The axial limiting inner pressure ring (2) specifically includes: a guide cone ring (2-1) and a hub pressure ring (2-2). The guide cone ring (2-1) is designed as a thin-walled cone ring with a taper of 135° with the central axis, so that the guide hole it opens is coaxial with the spherical self-aligning push rod.

4. A shaft diameter bidirectional limiting quenching mold based on phase change heat compensation according to claim 1, characterized in that: The multi-stage pressing radial limiting octagonal support body (3) adopts a 360° circular array around the central axis for floating support, specifically including: radial support slider (3-1), thermal response compensator (3-2), and spherical self-aligning push rod (3-3). The thermal response compensator (3-2) is made of nickel-titanium alloy with a high thermal expansion coefficient and is designed as a spring structure with a two-way effect. It is installed on the bottom limiting boss of the spherical self-aligning push rod and the countersunk seat of the radial support slider.

5. A shaft diameter bidirectional limiting quenching mold based on phase change heat compensation according to claim 1, characterized in that: The axial drive variable diameter mandrel (4) has eight variable diameter grooves (Ⅰ) arranged in a 360° circumferential array around the central axis on the side of the variable diameter cone, which are used to realize the variable diameter function of the multi-stage pressing radial limiting octagonal support (3). The expansion drive ball head (4-1) is configured as an ellipsoidal structure with a length range of 20-30mm, which is used for the expansion mandrel (5-3) that opens radially segmented.

6. A shaft diameter bidirectional limiting quenching mold based on phase change heat compensation according to claim 1, characterized in that: The lower mold support (5) is characterized in that: the multifunctional end face bearing ring (5-1) is arranged in a circumferential array around the central axis with 16 variable cross-section Laval-type oil drain grooves (II), the variable cross-section Laval-type oil drain grooves (II) apply the Venturi effect to accelerate the quenching oil from the bottom mold into the entire quenching chamber; the upper mating surface of the multifunctional end face bearing ring (5-1) is provided with an annular support surface and a raised constraint ring for positioning the gear position.

7. A shaft diameter bidirectional limiting quenching mold based on phase change heat compensation according to claim 1, characterized in that: The lower mold base (6) is provided with radial auxiliary flow channels to accelerate the flow rate of quenching oil from the center to the outside, which facilitates faster circulation and cooling of the quenching oil; the lower mold base (6) is provided with a wedge-shaped constraint boss structure to realize the radial limiting and positioning fixation of the multi-functional end face pressure ring in the mold.

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