Axial double replenishment process and die for driving axle housing hydraulic bulging

Abstract

A kind of axial double material supplementing process and mould of drive axle housing hydraulic bulging;For the hydraulic bulging of stepped tube with taper surface, the following processes can be flexibly realized: ① first material supplementing of pipe blank end, then material supplementing of sliding die ② material supplementing of pipe blank end and sliding die ③ first material supplementing of pipe blank end, then material supplementing of pipe blank end and sliding die ④ first material supplementing of pipe blank end, then material supplementing of pipe blank end and sliding die, finally only material supplementing of sliding die ⑤ only material supplementing of sliding die, etc. The mould includes sealing assembly and sliding die assembly, which are connected with horizontal inner and outer cylinders of hydraulic machine respectively, the inner and outer diameters of the inner cavities of left upper and lower sliding die blocks II and right upper and lower sliding die blocks II are all greater than the outer diameters of corresponding sections of stepped tube, the outer cylindrical surface diameters of left and right sealing inserts are equal to the outer diameter of pipe blank end, which can slide axially in the cavity of sliding die assembly with pipe blank end;The present application can reduce the maximum wall thickness reduction rate of bulged pipe, improve the limit bulging rate of pipe, reduce the product trial production cycle and cost.

Description

Technical Field

[0001] This invention relates to a hydraulic bulging axial feeding process and mold for a stepped tube with a conical surface, and particularly to a hydraulic bulging drive axle housing bulging feeding process and mold. Background Technology

[0002] The axle housing is one of the main load-bearing components in a rear-wheel-drive vehicle, and it is generally formed using several main methods, including casting, stamping-welding, and hydraulic bulging. Hydraulically bulged axle housings, due to their seamless construction and advantages in strength, rigidity, and fatigue life, have gradually gained market acceptance and are now being mass-produced. Because of the axle housing's long axial dimension (L = 1.3m–1.7m), the ratio of the height H of the central axle housing to the diameter D1 of the end tube is large (H / D1 = 2.9–3.6) (see...). Figure 1 Before the tube blank is expanded, the two ends of the straight tube need to be reduced in diameter multiple times by shrinking or spinning to reduce the diameter to the size of the round tube at the end of the bridge housing. Then, the middle part of the stepped tube with the conical surface after forming is subjected to one or two hydraulic expansions (see...). Figure 2 Finally, it is pressed into a bridge shell product.

[0003] Chinese invention patent application number 200710019709.6 discloses an internal high-pressure forming method for tubular parts with irregular cross-sections. It employs a fixed forming mold. After the upper and lower fixed molds are closed, high-pressure liquid is injected into the tube. Two pressure heads push the tube blank ends inward to extrude material. Under the combined action of liquid pressure and axial thrust, the metal tube undergoes plastic deformation and eventually adheres to the inner wall of the mold cavity. This process and mold, which relies solely on axial material filling from the tube blank ends, is more suitable for parts with short axial dimensions and a small central bulging ratio (the ratio of the diameter before and after bulging). Its biggest drawback is that when the metal at the tube blank ends flows towards the central bulging zone, it is hindered by the friction between the fixed mold and the tube wall (this friction is proportional to the friction coefficient between the tube wall and the mold, the internal pressure of the tube blank, and the length of the contact surface between the tube wall and the mold). The greater the friction, the worse the metal flowability. For bridge housings with long axial dimensions and large bulging ratio in the middle (1.5~1.9), only feeding material at the end of the tube blank results in a large reduction in wall thickness in the bulging zone, which easily leads to cracking.

[0004] Chinese invention patent application number 201010146622.7 discloses a semi-sliding hydraulic bulging process and mold for automotive axle housing parts. The mold uses a semi-sliding bulging mold whose main body consists of upper and lower fixed modules and left and right sliding modules. The left and right sliding modules are driven by the left and right sliders of a hydraulic press to move in opposite directions, performing two hydraulic bulging processes on the reduced-diameter tube blank. This overcomes the drawbacks of fixed forming molds. While the contact length between the sliding modules and the tube blank is still relatively long, except for the section between the sliding and fixed modules where relative movement and friction occur during the tube wall's contact with the cavity, the remaining parts have no relative displacement and are unaffected by friction. The sliding module and the tube blank end move at the same speed and displacement, which means that the tube blank end follows the sliding module and only plays a sealing role. This process and mold, which relies solely on the sliding module to push the central expansion area for axial material feeding, is more suitable for bridge shell forming (patents 2019101976767.2, 201110196728.2, and 201110196729), and can achieve a large expansion rate (maximum single expansion rate of 1.45-1.55). However, it still has the following shortcomings: ① The wall thickness reduction rate of the tube after expansion is still relatively large; ② It is difficult to achieve a larger expansion rate; ③ This process and mold, which relies solely on the sliding module for axial material feeding, is not very flexible. If the reserved material feeding length in the central expansion area of ​​the tube is too long or too short after the first expansion, wrinkles or cracks are likely to occur during the final expansion. In both cases, the length of the first expansion mold or even the cavity needs to be modified, which is time-consuming and labor-intensive, and seriously affects the product development cycle.

[0005] Chinese invention patent application number 202310361177.3 discloses a method for manufacturing heavy-duty truck axle housings. It uses a stepped tube blank, firstly undergoing axial and circumferential pre-expansion forming to obtain a pre-expansion tube blank with a flat upper side and outward convex lower and front / rear sides. After annealing, final expansion is performed to obtain the axle housing fitting. In addition to axial feeding via left and right sliding dies during pre-expansion, the circumferential feeding is achieved by designing the fixed mold cavity on the pre-expansion form as a flat shape, which allows for a larger tube diameter expansion ratio. However, its shortcomings are as follows: In the pre-expansion forming process, the expansion coefficient of the upper side of the tube blank is much smaller than that of the lower side. The same amount of axial feeding required to meet the wall thickness reduction of the lower side will cause metal accumulation on the upper side. In addition, the upper part is first attached to the mold during the forming process. Due to the influence of friction, the downward flow of the upper metal is blocked and cannot flow completely to the lower side. Excess metal will cause wrinkles on the upper side of the tube. The greater the difference between the diameter of the upper control mold and the diameter of the lower control mold, the greater the probability of wrinkles, which directly affects the subsequent pressing process, the cutting of the reinforcing ring, and the welding of the reinforcing ring. Summary of the Invention

[0006] The technical problem this invention aims to solve is as follows: Using a fixed mold and relying solely on axial feeding from the tube blank end results in poor feeding performance due to the long axial dimension of the tube end from the central bulging zone and the combined effects of friction, leading to easy cracking of the axle housing. Using a semi-sliding mold and relying solely on the sliding module for axial feeding still cannot achieve a larger bulging ratio or a smaller wall thickness reduction, and the inflexible axial feeding results in long product development cycles and high costs. Using a flat upper mold to achieve circumferential feeding easily causes wrinkles on the upper side of the tube, affecting subsequent welding of the reinforcing ring. This invention provides a hydraulic bulging process and mold for driving the axle housing with dual axial feeding, achieving dual axial feeding from the tube blank end and the sliding mold. Depending on the actual situation, it allows for flexible combinations of the two axial feeding methods, enabling several main axial feeding methods: ① tube blank end feeding first, then sliding mold feeding; ② tube blank end and sliding mold feeding together; ③ tube blank end feeding first, then end and sliding mold feeding together; ④ tube blank end feeding first, then end and sliding mold feeding together, finally only sliding mold feeding; ⑤ only sliding mold feeding.

[0007] The technical solution adopted by this invention to solve its technical problem is: a hydraulic expansion axial double-feeding mold for a drive axle housing, comprising a mold assembly and a sealing assembly; upper and lower fixed molds, a left sliding mold assembly composed of upper left and lower left sliding mold blocks I and II, a right sliding mold assembly composed of upper right and lower right sliding mold blocks I and II, and upper and lower mold guide seats forming the mold assembly; a left sealing assembly composed of a left sealing head, a left sealing block, and a left sealing insert, and a right sealing assembly composed of a right sealing head, a right sealing block, and a right sealing insert, together forming the sealing assembly.

[0008] The hydraulic bulging axial double-feeding mold for the drive axle housing is characterized by the following: the upper and lower mold guides are respectively fixed to the vertical slider and the worktable of the three-way hydraulic press; the upper and lower fixed molds are respectively fixed to the middle of the upper and lower mold guides; the upper left and lower sliding mold blocks I located on the left side of the upper and lower fixed molds are respectively connected to the right end faces of the upper left and lower sliding mold blocks II by bolts; the left end faces of the upper left and lower sliding mold blocks II are fixed to the left horizontal outer cylinder end face of the three-way hydraulic press by bolts; the upper right and lower sliding mold blocks I located on the right side of the upper and lower fixed molds are respectively connected to the left end faces of the upper right and lower sliding mold blocks II by bolts; the right end faces of the upper right and lower sliding mold blocks II are fixed to the right horizontal outer cylinder end face of the three-way hydraulic press by bolts; and the left and right sliding mold assemblies can slide within the upper and lower mold guides as the left and right horizontal outer cylinders move.

[0009] The sealing assembly of the hydraulic expansion axial double-feeding mold for the drive axle housing is characterized by the following: the left and right sealing heads are connected to the end faces of the left and right horizontal inner cylinders of the three-way hydraulic press through the connecting holes on the flanges, respectively; the inner cylindrical surfaces of the left and right sealing heads mate with the outer cylindrical surfaces of the left and right sealing inserts, respectively, and are sealed to the high-pressure oil through Ω-shaped sealing rings; the inner cylindrical surfaces of the left and right sealing inserts mate with the inner holes of the left and right sealing blocks, respectively; the left and right sealing blocks are pressed and fixed to the left and right sealing heads by bolts, respectively; and the left and right sealing assemblies can slide axially within the cavity formed by the upper left and lower sliding mold blocks II and the upper right and lower sliding mold blocks II, respectively, with the end of the tube blank.

[0010] The hydraulic expansion axial double-feeding mold for the drive axle housing is characterized by sliding mold blocks II: upper left and lower sliding mold blocks II and upper right and lower sliding mold blocks II, with inner and outer diameters ΦD of their inner cavities. 2模 ΦD 1模 The diameters should be greater than the corresponding outer diameters ΦD2 and ΦD1 of the stepped pipe, respectively, i.e., ΦD 2模 >ΦD2、ΦD 1模 >ΦD1, with a diameter difference of about 2 to 4 mm, its length should ensure that at the initial stage of hydraulic bulging (before the working process), its outer end face exceeds the end of the stepped tube or is flush with the end of the tube blank, that is, to ensure that the upper left and lower sliding mold blocks II and the upper right and lower sliding mold blocks II fully cover the end of the tube blank.

[0011] The hydraulic expansion axial double-feeding mold for the drive axle housing has the following characteristics for its sealing inserts: the diameter ΦD of the inner outer cylindrical surface of the left and right sealing inserts is equal to the outer diameter ΦD1 of the tube blank end, i.e., ΦD=ΦD1, which ensures that it can slide axially with the tube blank end in the cavity composed of the upper left and lower sliding mold blocks II and the upper right and lower sliding mold blocks II, respectively.

[0012] The working process of the hydraulic bulging axial double-feeding mold for the drive axle housing is as follows:

[0013] ① Place the stepped tube on the lower fixed mold, and the vertical slider of the three-way hydraulic press drives the upper mold guide to move downward to the mold closing position.

[0014] ②The left and right horizontal inner cylinders of the three-way hydraulic press drive the left and right sealing components to move inward to a distance S0 after contacting the end of the tube blank, thereby sealing the end of the tube blank.

[0015] ③ The left and right horizontal outer cylinders of the three-way hydraulic press drive the left and right sliding mold assemblies to move inward to the predetermined initial position.

[0016] ④ High-pressure liquid is introduced into the stepped pipe. At the same time, the left and right horizontal inner cylinders of the three-way hydraulic press drive the left and right sealing components respectively, and the left and right outer cylinders drive the left and right sliding mold components respectively, moving inward to the mold closing position according to the predetermined sequence, speed and distance.

[0017] ⑤ Depressurization: The left and right horizontal inner and outer cylinders of the three-way hydraulic press return to their original positions, and the ejector cylinder on the working platform ejects the pipe upwards.

[0018] The hydraulic bulging axial double-feeding process for the drive axle housing is characterized by:

[0019] At the initial stage of hydraulic bulging (after sealing the tube blank ends and before the left and right sliding mold assemblies advance), the axial distance between the right end face of the upper left and lower sliding mold segment I and the left end face of the upper and lower fixed molds is equal to the axial distance between the left end face of the upper right and lower sliding mold segment I and the right end face of the upper and lower fixed molds, which is S. h The axial distance between the right end face of the left sealing block and the left end face of the upper left and lower left sliding mold segment II is equal to the axial distance between the left end face of the right sealing block and the right end face of the upper right and lower right sliding mold segment II, which is S. d The axial distance between the conical surface of the upper left and lower sliding mold block I and the left conical surface of the stepped tube is equal to the axial distance between the conical surface of the upper right and lower sliding mold block I and the right conical surface of the stepped tube, which is S. d0 (When the conical surfaces of the upper left and lower sliding mold blocks I coincide with the left conical surface of the stepped tube, and the conical surfaces of the upper right and lower sliding mold blocks I coincide with the right conical surface of the stepped tube, S) d0 =0); During hydraulic bulging, the inward feed speed of the left and right sliding mold assemblies is always V. h The inward working speed of the left and right sealing components is the same at V. d (V d≥ V h If the values ​​before and after are different, then the initial value should be based on speed V. d1 Inward working to the left and right sliding module assembly inward working S h1 After the distance, press speed V d2 The process proceeds to mold closing.

[0020] ①a. Set S d0 >0, S h V d =V h That is, the left and right sealing components and the left and right sliding mold components move at the same speed V. d =V h Works S h The distance from the mold closing position allows for material feeding at the billet end first, followed by material feeding at the sliding mold. In this case, the material feeding length at the billet end is S. d0 The sliding die feeding length is S h -S d0 S should be set d ≥0mm.

[0021] b. Set S d0 =0, S h S h1< Sh V d1> V h V d2 =V h That is, the initial left and right sealing components are set according to V. d1 Speed, left and right sliding module components press V h Speed, simultaneously feed to the left and right sliding module components S h1 After the distance is reached, the left and right sealing components move at the same speed V as the left and right sliding mold components. d2 =V h When the feed reaches the mold closing position, material can be added to the tube blank end first, followed by material addition to the sliding mold. In this case, the material addition length to the tube blank end is S. h1 (V d1 / V h -1), S should be set d ≥S h (V d / V h -1), the sliding die feeding length is S h .

[0022] ② Set S d0 =0, S h V d> V h That is, the left and right sealing components are at a speed V d The left and right sliding module components move at speed V. h Simultaneously, the feed advances to the mold closing position, allowing for simultaneous material replenishment at the tube blank end and through the sliding mold. At this point, the material replenishment length through the sliding mold is S. h The length of material added to the end of the tube blank is S. h (V d / V h -1), S should be set d ≥S h (V d / V h -1).

[0023] ③ Set S d0 >0, S h V d> V h That is, the left and right sealing components are at a speed V d And the left and right sliding module components according to speed V h Simultaneous feeding of different speeds into the mold allows for material replenishment at the billet end first, followed by simultaneous replenishment at the end and sliding mold. At this point, the replenishment length of the sliding mold is S. h -S d0 The length of material added to the end of the tube blank is S. d0 +(S h -S d0 (V) d / V h -1), S should be setd ≥(S h -S d0 (V) d / V h -1).

[0024] ④ Set S d0 >0, S h1< S h V d1> V h V d2 =V h That is, the initial left and right sealing components are set according to V. d1 Speed, left and right sliding module components press V h Speed, simultaneously feed to the left and right sliding module components S h1 After the distance is reached, the left and right sealing components move at the same speed V as the left and right sliding mold components. d2 =V h When the feed reaches the mold closing position, material can be fed to the tube blank end first, then simultaneously to the end and the sliding mold, and finally only to the sliding mold. At this point, the material feeding length of the sliding mold is S. h -S d0 The length of material added to the end of the tube blank is S. d0 +(S h1 -S d0 (V) d1 / V h -1), S should be set d ≥(S h1 -S d0 (V) d1 / V h -1).

[0025] ⑤ Set S d0 =0, S h V d =V h That is, the left and right sealing components and the left and right sliding mold components advance at the same speed S. h By adjusting the distance to the mold closing position, material replenishment can be achieved using only the sliding mold. In this case, the material replenishment length of the sliding mold is S. h S should be set d ≥0mm.

[0026] The beneficial effects of this invention are: ① It can reduce the maximum wall thickness reduction rate of the expanded pipe fitting (when the pipe material, mold, and expansion rate are the same, comparing the biaxial feeding method with the sliding mold feeding method). ② It can increase the ultimate expansion rate of the pipe fitting (when the material and the thickness and circumferential strain ratio of the expanded pipe material are the same, comparing the biaxial feeding method with the sliding mold feeding method). ③ When designing the expansion mold, the expansion feeding length in the middle of the expanded pipe is designed with the smaller value, and the insufficient feeding amount is made up from the end of the pipe blank, which can greatly reduce the probability of mold repair during the product trial production process, and reduce the product trial production cycle and cost. Attached Figure Description

[0027] Figure 1 This is a simplified diagram of a certain drive axle housing;

[0028] Figure 2 It is a stepped tube with a tapered surface used in the hydraulic bulging process of a certain drive axle housing;

[0029] Figure 3 It is the first tube after expansion in the hydraulic expansion process of a certain drive axle housing;

[0030] Figure 4 It is the tube after final expansion in the hydraulic expansion process of a certain drive axle housing;

[0031] Figure 5 This is a simplified diagram of an axial double-feeding mold for the front expansion of a certain drive axle housing;

[0032] Figure 6 This is a simplified diagram of an axial double-feeding mold for the final expansion of a certain drive axle housing;

[0033] Reference numerals: 1, 1′. Left and right sealing heads; 2, 2′. Connecting holes; 3, 3′. Ω-shaped sealing rings; 4, 4′. Left and right sealing inserts; 5, 5′. Left and right sealing blocks; 6, 6′, 8, 8′, 8″, 8″′, 12, 12′, 12″, 12′″, 15, 15′, 15″, 15″′, 18, 18′, 18″, 18″′. Bolts; 7, 7′. Oil passages; 9, 9″. Upper left sliding mold section II; 9′, 9″′. Lower left sliding mold section II. Block II, 10, 10″. Upper left sliding mold block I, 10′, 10′″. Lower left sliding mold block I, 11, 11″. Stepped tube, 13, 13′. Upper and lower sliding mold guides, 14, 14″. Upper fixed mold, 14′, 14′″. Lower fixed mold, 16, 16″. Upper right sliding mold block I, 16′, 16′″. Lower right sliding mold block I, 17, 17″. Upper right sliding mold block II, 17′, 17′″. Lower right sliding mold block II, 19. High-pressure pipe connector. Detailed Implementation

[0034] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings.

[0035] Example:

[0036] Figure 1 This is a simplified diagram of a drive axle housing, where H = 510mm, L = 1555mm, and ΦD1 = 142mm. Figure 2 , 3 4 and 5 represent the stepped tube with tapered surface, the tube after the first expansion, and the tube after the final expansion in the hydraulic expansion process of a certain drive axle housing, respectively. Figure 2The outer diameter of the middle expansion zone of the stepped tube is φ0 = 273 mm, the initial wall thickness is t0 = 10.5 mm, the outer diameter of the transition arc of the stepped tube is ΦD2 = 176 mm, and the stepped tube is asymmetrical (the left and right transition arcs have cone angles θ). f ≠θ r and radius R f ≠R r And the lengths of the left and right sides are l f0 ≠l r0 ); Figure 3 After the initial expansion, the diameter of the middle section of the tube is φ1 = 368 mm, the wall thickness is t1 = 9.3 mm, and the lengths on the left and right sides are l. f1 ≠l r1 ; Figure 4 After final bulging, the upper diameter of the central cross-section of the tube is R1 = 231 mm, the lower diameter is R2 = 239 mm, and the lengths on the left and right sides are l. f2 ≠l r2 . Figure 5 , 6 These are simplified diagrams of the axial double-feeding molds for the initial and final bulging of a drive axle housing. In this invention, the axial double-feeding molds for the initial and final bulging of the drive axle housing have the same structure, connection positions, and movement process, and the sealing components and upper and lower mold guides are interchangeable. Considering that the final bulging of the tube in this invention is more typical due to its asymmetry both horizontally and vertically, only the axial double-feeding process and mold for the final bulging of the drive axle housing will be specifically described:

[0037] The axial double-feeding mold for the final expansion of the drive axle housing in this invention includes a mold assembly and a sealing assembly. The mold assembly consists of upper and lower fixed molds (14, 14'), a left sliding mold assembly composed of upper and lower left sliding mold blocks I (10, 10') and upper and lower left sliding mold blocks II (9, 9'), a right sliding mold assembly composed of upper and lower right sliding mold blocks I (16, 16') and upper and lower right sliding mold blocks II (17, 17'), and upper and lower mold guides (13, 13'). The sealing assembly consists of a left sealing pressure head 1, a left sealing pressure block 5, and a left sealing insert 4, and a right sealing pressure head 1', a right sealing pressure block 5', and a right sealing insert 4'.

[0038] The upper and lower mold guides (13, 13') are fixed to the vertical slide block and the worktable of the three-way hydraulic press, respectively. The upper and lower fixed molds (14, 14') are fixed to the middle of the upper and lower mold guides (13, 13'), respectively. The upper left and lower sliding mold blocks I (10, 10') located on the left side of the upper and lower fixed molds (14, 14') are connected to the right end face of the upper left and lower sliding mold blocks II (9, 9') respectively by bolts (12, 12'). The left end face of the upper left and lower sliding mold blocks II (9, 9') is fixed to the three-way hydraulic press by bolts (8, 8'). On the left side of the press's horizontal outer cylinder end face, the upper right and lower right sliding mold blocks I (16, 16') located to the right of the upper and lower fixed molds (14, 14') are connected to the left end faces of the upper right and lower right sliding mold blocks II (17, 17') respectively by bolts (15, 15'). The right end faces of the upper right and lower right sliding mold blocks II (17, 17') are fixed to the right side of the three-way hydraulic press's horizontal outer cylinder end face by bolts (18, 18'). The left and right sliding mold assemblies can slide within the upper and lower mold guide seats (13, 13') as the left and right horizontal outer cylinders move.

[0039] The left and right sealing heads (1, 1') are connected to the left and right horizontal inner cylinder end faces of the three-way hydraulic press through the connecting holes (2, 2') on the flange, respectively. The inner cylindrical surfaces of the left and right sealing heads (1, 1') are respectively engaged with the outer cylindrical surfaces of the left and right sealing inserts (4, 4'), and the high-pressure oil is sealed by the Ω-shaped sealing rings (3, 3'). The inner cylindrical surfaces of the left and right sealing inserts (4, 4') are respectively engaged with the inner holes of the left and right sealing blocks (5, 5'). The left and right sealing blocks (5, 5') are respectively pressed and fixed to the left and right sealing heads (1, 1') by bolts (6, 6'). Under the drive of the left and right horizontal inner cylinders, the left and right sealing assemblies can slide axially in the cavity formed by the upper left and lower sliding mold blocks II (9, 9') and the upper right and lower sliding mold blocks II (17, 17') with the tube blank end, respectively.

[0040] The inner and outer diameters ΦD of the upper left and lower sliding mold blocks II (9, 9') and the upper right and lower sliding mold blocks II (17, 17') have the following characteristics: 2模 =178mm, ΦD 1模 =144mm, which is 2mm larger than the outer diameter of the corresponding section of the stepped tube (ΦD2=176mm, ΦD1=142mm) respectively, before the left and right sliding module components are advanced (S d0 When =0), its outer end face is flush with the end of the stepped tube; the inner outer cylindrical surface diameter of the left and right sealing inserts (4, 4′) is ΦD=ΦD1=142mm.

[0041] The working process of the axial double-feeding mold for the final bulging of the axle housing in this invention is as follows:

[0042] ① Place the stepped tube 11 on top of the lower fixed mold 14′, and the vertical slider of the three-way hydraulic press drives the upper mold guide seat 13 to move downward to the mold closing position.

[0043] ② The left and right horizontal inner cylinders of the three-way hydraulic press drive the left and right sealing components to move inward until they contact the end of the tube blank by 3mm, thereby sealing the end of the tube blank.

[0044] ③ The left and right horizontal outer cylinders of the three-way hydraulic press drive the left and right sliding mold assemblies to move inward to the predetermined initial position.

[0045] ④ High-pressure liquid is introduced into the stepped pipe 11. At the same time, the left and right horizontal inner cylinders of the three-way hydraulic press drive the left and right sealing components respectively, and the left and right outer cylinders drive the left and right sliding mold components respectively, moving inward to the mold closing position according to the predetermined sequence, speed and distance.

[0046] ⑤ Depressurization: The left and right horizontal inner and outer cylinders of the three-way hydraulic press return to their original positions, and the ejector cylinder on the working platform ejects the pipe upwards.

[0047] The meanings and specific values ​​of the parameters in the axial double-feeding process for the final bulging of the drive axle housing in this invention are as follows:

[0048] At the initial stage of hydraulic bulging (after sealing the tube blank ends and before the left and right sliding mold assemblies advance), the axial distance between the right end face of the upper left and lower sliding mold segments I (10, 10') and the left end face of the upper and lower fixed molds (14, 14') is equal to the axial distance between the left end face of the upper right and lower sliding mold segments I (16, 16') and the right end face of the upper and lower fixed molds (14, 14'), which is S. h The axial distance between the right end face of the left sealing block 5 and the left end face of the upper and lower sliding mold blocks II (9, 9') is equal to the axial distance between the left end face of the right sealing block 5' and the right end face of the upper and lower sliding mold blocks II (17, 17'), which is S. d The axial distance between the conical surfaces of the upper left and lower left sliding mold blocks I (10, 10') and the left side conical surface of the stepped tube 11 is equal to the axial distance between the conical surfaces of the upper right and lower right sliding mold blocks I (16, 16') and the right side conical surface of the stepped tube 11, which is S. d0 (When the conical surfaces of the upper left and lower sliding mold blocks I (10, 10') coincide with the left conical surface of the stepped tube 11, and the conical surfaces of the upper right and lower sliding mold blocks I (16, 16') coincide with the right conical surface of the stepped tube 11, S d0 =0); During hydraulic bulging, the inward feed speed of the left and right sliding mold assemblies is always V. h The inward working speed of the left and right sealing components is the same at V. d (V d≧ V h If the values ​​before and after are different, then the initial value should be based on speed V. d1Inward working to the left and right sliding module assembly inward working S h1 After the distance, press speed V d2 The process proceeds to mold closing.

[0049] ①a. Set S d0 =4mm, S h =38mm, V d =V h =2mm / s, meaning the left and right sealing components and the left and right sliding mold components move at the same speed V. d =V h Works S h The distance from the mold closing position allows for material feeding at the billet end first, followed by material feeding at the sliding mold. In this case, the material feeding length at the billet end is S. d0 =4mm, sliding die feeding length is S h -S d0 =34mm, S should be set d ≥0mm, the wall thickness at the lower end of the central section of the tube after final expansion is 8.37mm, and the maximum wall thickness reduction rate is 10.4%, which is less than that of the sliding mold feeding mode only.

[0050] b. Set S d0 =0, S h =34mm, S h1 =8mm, V d1 =3mm / s, V d2 =V h =2mm / s, meaning the initial left and right sealing components are at V... d1 Speed, left and right sliding module components press V h Speed, simultaneously feed to the left and right sliding module components S h1 After the distance is reached, the left and right sealing components move at the same speed V as the left and right sliding mold components. d2 =V h When the feed reaches the mold closing position, material can be added to the tube blank end first, followed by material addition to the sliding mold. In this case, the material addition length to the tube blank end is S. h1 (V d1 / V h -1) = 4mm, S should be set d ≥S h (V d / V h -1) = 4mm, the sliding die feeding length is S h =34mm.

[0051] ② Set S d0 =0, S h =34mm, V d =2.5mm / s, V h =2mm / s, meaning the left and right sealing components move at a speed of V dThe left and right sliding module components move at speed V. h Simultaneously, the feed advances to the mold closing position, allowing for simultaneous material replenishment at the tube blank end and through the sliding mold. At this point, the material replenishment length through the sliding mold is S. h =34mm, the blank end feeding length is S h (V d / V h -1) = 8.5mm, S should be set d ≥S h (V d / V h -1)=8.5mm, the wall thickness of the lower end of the central section of the tube after final expansion is 8.31mm, the maximum wall thickness reduction rate is 11.0%, which is less than that of the sliding mold feeding mode only.

[0052] ③ Set S d0 =4mm, S h =30mm, V d =3mm / s, V h =1.5mm / s, meaning the left and right sealing components move at a speed V d And the left and right sliding module components according to speed V h Simultaneous feeding of different speeds into the mold allows for material replenishment at the billet end first, followed by simultaneous replenishment at the end and sliding mold. At this point, the replenishment length of the sliding mold is S. h -S d0 =26mm, the blank end feeding length is S d0 +(S h -S d0 (V) d / V h -1) = 30mm, S should be set d ≥(S h -S d0 (V) d / V h -1) = 26mm, and the wall thickness at the lower apex of the center section of the final bulging tube after forming is 8.21mm, which is comparable to the sliding mold feeding mode. At this time, the middle length of the first bulging tube is 12mm shorter than the middle length of the first bulging tube in the sliding mold feeding mode, but it can still be formed into a qualified final bulging tube.

[0053] ④ Set S d0 =4mm, S h =38mm, S h1 =12mm, V d1 =3mm / s, V d2 =V h =2mm / s, meaning the initial left and right sealing components are at V... d1 Speed, left and right sliding module components press V h Speed, simultaneously feed to the left and right sliding module components Sh1 After the distance is reached, the left and right sealing components move at the same speed V as the left and right sliding mold components. d2 =V h When the feed reaches the mold closing position, material can be fed to the tube blank end first, then simultaneously to the end and the sliding mold, and finally only to the sliding mold. At this point, the material feeding length of the sliding mold is S. h -S d0 =34mm, the blank end feeding length is S d0 +(S h1 -S d0 (V) d1 / V h -1) = 8mm, S should be set d ≥(S h1 -S d0 (V) d1 / V h -1) = 4mm. The wall thickness at the lower apex of the center section of the tube after final bulging is 8.44mm, with a maximum wall thickness reduction rate of 9.6%, which is about 20% lower than that of the sliding mold feeding mode.

[0054] ⑤ Set S d0 =0, S h =34mm, V d =V h =2mm / s, meaning the left and right sealing components and the left and right sliding mold components advance at the same speed (S). h By adjusting the distance to the mold closing position, material replenishment can be achieved using only the sliding mold. In this case, the material replenishment length of the sliding mold is S. h =34mm, S should be set d ≥0mm, the wall thickness at the lower apex of the center section of the tube after final expansion is 8.21mm, and the maximum thinning rate is 12.1%.

Claims

1. A hydraulic bulging process for drive axle housings with axial dual-feeding, specifically for hydraulic bulging of stepped tubes with tapered surfaces, enabling axial dual-feeding at the tube blank end and in the sliding die; wherein, The upper left and lower left sliding mold blocks I (10, 10') and the upper left and lower left sliding mold blocks II (9, 9') form the left sliding mold assembly; the upper right and lower right sliding mold blocks I (16, 16') and the upper right and lower right sliding mold blocks II (17, 17') form the right sliding mold assembly; the left sealing assembly includes a left sealing pressure block (5), and the right sealing assembly includes a right sealing pressure block (5'); the specific process is as follows: At the initial stage of hydraulic bulging, i.e. after the tube blank end is sealed and before the left and right sliding mold assemblies advance, the axial distance between the right end face of the upper left and lower sliding mold segments I (10, 10') and the left end face of the upper and lower fixed molds (14, 14') is equal to the axial distance between the left end face of the upper right and lower sliding mold segments I (16, 16') and the right end face of the upper and lower fixed molds (14, 14'), which is S. h The axial distance between the right end face of the left sealing block (5) and the left end face of the upper and lower sliding mold blocks II (9, 9') is equal to the axial distance between the left end face of the right sealing block (5') and the right end face of the upper and lower sliding mold blocks II (17, 17'), which is S. d The axial distance between the conical surfaces of the upper left and lower sliding mold blocks I (10, 10′) and the left conical surface of the stepped tube (11) is equal to the axial distance between the conical surfaces of the upper right and lower sliding mold blocks I (16, 16′) and the right conical surface of the stepped tube (11), which is S. d0 When the conical surfaces of the upper left and lower sliding mold blocks I (10, 10′) coincide with the left conical surface of the stepped tube (11), and the conical surfaces of the upper right and lower sliding mold blocks I (16, 16′) coincide with the right conical surface of the stepped tube (11), S d0 =0; During hydraulic bulging, the inward feed speed of the left and right sliding mold assemblies is always V. h The inward working speed of the left and right sealing components is V when the front and rear are the same. d V d V h If the preceding and following times are different, then the initial time is based on speed V. d1 Inward working to the left and right sliding module assembly inward working S h1 After the distance, press speed V d2 The process proceeds to mold closing; a. Set S d0 >0, V d =V h That is, the left and right sealing components and the left and right sliding mold components advance at the same speed S. h The distance from the mold closing position allows for material feeding to the tube blank end first, followed by material feeding to the sliding mold; at this time, the material feeding length at the tube blank end is S. d0 The sliding die feeding length is S h -S d0 It should be set ; b. Set S d0 =0, V d1 >V h V d2 =V h That is, the initial left and right sealing components are set according to V. d1 Speed, left and right sliding module components press V h Speed, simultaneously feed to the left and right sliding module components S h1 After the distance is reached, the left and right sealing components and the left and right sliding mold components advance to the mold closing position at the same speed, which can also achieve material replenishment at the tube blank end first and then material replenishment at the sliding mold; at this time, the material replenishment length at the tube blank end is It should be set The sliding die feeding length is S h ; Set S d0 =0, V d >V h That is, the left and right sealing components are at a speed V d The left and right sliding module components move at speed V. h Simultaneously, the feed advances to the mold closing position, allowing for simultaneous material replenishment at the tube blank end and through the sliding mold; at this point, the material replenishment length of the sliding mold is S. h The length of material added to the end of the tube blank is It should be set ; Set S d0 >0, V d >V h That is, the left and right sealing components are at a speed V d And the left and right sliding module components according to speed V h Simultaneous feeding of different speeds into the mold closing position allows for material replenishment at the tube blank end first, followed by simultaneous feeding of the tube blank end and the sliding mold; at this time, the feeding length of the sliding mold is S. h -S d0 The length of material added to the end of the tube blank is It should be set ; Set S d0 >0, V d1 >V h V d2 =V h That is, the initial left and right sealing components are set according to V. d1 Speed, left and right sliding module components press V h Speed, simultaneously feed to the left and right sliding module components S h1 After the distance is reached, the left and right sealing components and the left and right sliding mold components advance to the mold closing position at the same speed, which can realize the following: first, the tube blank end is fed with material, then the tube blank end and the sliding mold are fed with material simultaneously, and finally only the sliding mold is fed with material; at this time, the feeding length of the sliding mold is S. h -S d0 The length of material added to the end of the tube blank is It should be set ; Set S d0 =0, V d =V h That is, the left and right sealing components and the left and right sliding mold components advance at the same speed S. h The distance to the mold closing position allows for material replenishment only through the sliding mold; at this point, the material replenishment length of the sliding mold is S. h It should be set .

2. A hydraulic bulging axial double-feeding mold for a drive axle housing used in the process described in claim 1, characterized in that, The mold assembly includes a mold assembly and a sealing assembly; the mold assembly consists of upper and lower fixed molds (14, 14'), a left sliding mold assembly, a right sliding mold assembly, and upper and lower mold guides (13, 13'); the left sealing assembly consists of a left sealing head (1), a left sealing block (5), and a left sealing insert (4); the right sealing assembly consists of a right sealing head (1'), a right sealing block (5'), and a right sealing insert (4'); together they form the sealing assembly. The upper and lower mold guides (13, 13') are fixed to the vertical slide block and the worktable of the three-way hydraulic press, respectively. The upper and lower fixed molds (14, 14') are fixed to the middle of the upper and lower mold guides (13, 13'), respectively. The upper left and lower sliding mold segments I (10, 10') located on the left side of the upper and lower fixed molds (14, 14') are connected to the right end face of the upper left and lower sliding mold segments II (9, 9') respectively by bolts (12, 12'). The left end face of the upper left and lower sliding mold segments II (9, 9') is fixed to the three-way hydraulic press by bolts (8, 8'). On the left side of the horizontal outer cylinder end face of the press, the upper right and lower right sliding mold blocks I (16, 16') located to the right of the upper and lower fixed molds (14, 14') are connected to the left end face of the upper right and lower right sliding mold blocks II (17, 17') respectively by bolts (15, 15'). The right end face of the upper right and lower right sliding mold blocks II (17, 17') is fixed to the right side of the horizontal outer cylinder end face of the three-way hydraulic press by bolts (18, 18'). The left and right sliding mold assemblies can slide within the upper and lower mold guide seats (13, 13') as the left and right horizontal outer cylinders move. The left and right sealing heads (1, 1') are connected to the left and right horizontal inner cylinder end faces of the three-way hydraulic press through the connecting holes (2, 2') on the flange, respectively. The inner cylindrical surfaces of the left and right sealing heads (1, 1') are respectively engaged with the outer cylindrical surfaces of the left and right sealing inserts (4, 4'), and the high-pressure oil is sealed by the Ω-shaped sealing rings (3, 3'). The inner outer cylindrical surfaces of the left and right sealing inserts (4, 4') are respectively engaged with the inner holes of the left and right sealing blocks (5, 5'). The left and right sealing blocks (5, 5') are respectively pressed and fixed on the left and right sealing heads (1, 1') by bolts (6, 6'). Under the drive of the left and right horizontal inner cylinders, the left and right sealing assemblies can slide axially in the cavity formed by the upper left and lower sliding mold blocks II (9, 9') and the upper right and lower sliding mold blocks II (17, 17') with the tube blank end. The inner end diameter ΦD of the inner cavity of the upper left and lower sliding mold blocks II (9, 9') and the upper right and lower sliding mold blocks II (17, 17') 2模 The outer diameter ΦD2 of the corresponding section of the stepped tube is greater than the outer diameter ΦD of the outer end. 1模 The outer diameter ΦD1 of the corresponding segment of the stepped tube is greater than that of the tube. The lengths of the upper left and lower sliding mold blocks II (9, 9′) and the upper right and lower sliding mold blocks II (17, 17′) should ensure that at the beginning of the hydraulic expansion, their outer end faces exceed the tube blank end or are flush with the tube blank end, that is, ensure that the upper left and lower sliding mold blocks II (9, 9′) and the upper right and lower sliding mold blocks II (17, 17′) fully cover the tube blank end. The inner outer cylindrical surface diameter ΦD of the left and right sealing inserts (4, 4′) is equal to the outer diameter ΦD1 of the tube blank end, i.e. ΦD=ΦD1, ensuring that it can slide axially with the tube blank end in the cavity composed of the upper left and lower sliding mold blocks II (9, 9′) and the upper right and lower sliding mold blocks II (17, 17′).

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