A hot extrusion forming method for high-precision aluminum alloy tubes with head-end traction and a traction mechanism

Abstract

The present invention belongs to the technical field of aviation pipe materials, and discloses a hot extrusion forming method for high-precision aluminum alloy pipes with head-end traction and a traction mechanism. The method is to use the extrusion method to extrude aluminum alloy billets to produce aluminum alloy pipes. The pipe outlet hole is arranged directly below the extrusion equipment. A traction mechanism is arranged outside the pipe outlet hole. After the aluminum alloy pipe extends out of the pipe outlet hole and contacts the traction mechanism, the traction mechanism automatically locks the end of the aluminum alloy pipe and moves vertically downward in cooperation with the extrusion speed of the aluminum alloy pipe to ensure the straightness of the aluminum alloy pipe. The present invention reforms and designs the traction mechanism for a 20MN pipe precision hot extrusion machine, and uses compressed air to control the release and tightening of the traction mechanism to complete the motion binding between the traction mechanism and the pipe, so that the straightness of the extruded pipe can meet the requirements. The speed of the traction mechanism of the present invention is matched with the extrusion forming speed, and the telescopic oil cylinder is triggered by a pressure sensor, which can quickly and automatically complete the processing of aluminum alloy pipes.

Description

Technical Field

[0001] The present invention belongs to the technical field of aviation tubes, and relates to a manufacturing method of high-precision aluminum alloy tubes for helicopter tail drive shafts, specifically to a hot extrusion forming method of high-precision aluminum alloy tubes with head-end traction. Background Art

[0002] Currently, a 20MN vertical tube precision hot extrusion press is used to produce large-diameter thin-wall aluminum alloy extrusion tubes as the blanks for high-precision aluminum alloy tubes for a certain type of medium and small diameter helicopter tail drive shafts. It has many cold working passes, and an intermediate heat treatment process is required after each cold working pass, which easily leads to coarse grains and poor mechanical properties of the finished tubes.

[0003] To shorten the processing flow of tubes for helicopter tail shafts, smaller-sized extrusion tubes are selected as cold working blanks, but the current straightness requirements of the extrusion tubes cannot meet the high-precision requirements of helicopter tail shafts. Summary of the Invention

[0004] To solve the above problems, the present invention provides a hot extrusion forming method of high-precision aluminum alloy tubes with head-end traction, and designs a head-end traction mechanism for the tubes to ensure the straightness requirements.

[0005] The technical solution of the present invention is as follows:

[0006] A hot extrusion forming method of high-precision aluminum alloy tubes with head-end traction uses the extrusion method to extrude aluminum alloy tubes from an aluminum alloy ingot. The tube die hole is arranged directly below the extrusion equipment, and a traction mechanism is arranged outside the tube die hole. After the aluminum alloy tube extends out of the tube die hole and contacts the traction mechanism, the traction mechanism automatically locks the end of the aluminum alloy tube and moves vertically downward in coordination with the extrusion speed of the aluminum alloy tube to ensure the straightness of the aluminum alloy tube.

[0007] Further, before extrusion, the aluminum alloy ingot is first heated to 420 - 430 °C and kept warm for at least 30 minutes, and the extrusion die is heated to 430 - 440 °C and kept warm for at least 30 minutes.

[0008] A traction mechanism used in a hot extrusion forming method of high-precision aluminum alloy tubes with head-end traction includes a traction expansion head and a telescopic oil cylinder. The telescopic oil cylinder is arranged directly below the tube die hole, the telescopic rod of the telescopic oil cylinder extends vertically upward outside the tube die hole, and the traction expansion head is installed at the top of the telescopic rod. The traction expansion head automatically expands and tightens and fixes from the inner wall of the aluminum alloy tube after contacting the aluminum alloy tube.

[0009] Further, the initial state of the telescopic oil cylinder is the maximum extended state. After the traction expansion head expands and tightens and fixes the aluminum alloy tube, the telescopic rod of the telescopic oil cylinder gradually contracts to the minimum contracted state; the telescopic distance of the telescopic oil cylinder matches the length of the aluminum alloy tube.

[0010] Furthermore, the traction expander head includes a base, a pull rod, a driving block, left and right clamping teeth, and a pressure sensor. The base has a structure with left and right double inclined planes at the top and a through hole inside. The pull rod passes through the internal through hole of the base and its bottom is connected to the end of the telescopic rod of the telescopic oil cylinder. A fixed driving block is installed on the pull rod. The driving block is located above the base. Left and right clamping teeth are respectively installed on the left and right sides of the driving block. The tops of the left and right clamping teeth are rotatably connected to the upper end of the pull rod. The lower parts of the left and right clamping teeth are inclined planes and are placed on the left and right double inclined planes of the base.

[0011] Furthermore, it also includes guide posts. The guide posts are fixedly connected to the top of the pull rod. The left and right clamping teeth are respectively rotatably connected to the left and right sides of the guide posts.

[0012] Furthermore, the top of the guide post is an arc body, and the guide post is facing the die orifice of the pipe.

[0013] Furthermore, the left and right double inclined planes at the top of the base are specifically two inclined dovetail grooves. The lower halves of the left and right clamping teeth are respectively arranged in the two inclined dovetail grooves; there are grooves in the middle sections of the left and right clamping teeth, and the driving block is stuck at the grooves of the left and right clamping teeth.

[0014] Furthermore, it also includes a protective cover. The bottom of the base has a convex edge. The protective cover is an annular ring sleeved outside the base and above the convex edge; among them, a spring is arranged between the protective cover and the convex edge of the base. The pressure sensor is arranged on the convex edge of the base; when the pressure sensor detects the touch at the bottom of the protective cover, the telescopic rod of the telescopic oil cylinder starts to contract.

[0015] The beneficial effects of the present invention are as follows:

[0016] 1. The present invention reforms the 20MN pipe precision hot extrusion machine, designs a traction mechanism at the lower end of the die orifice, uses compressed air to control the release and tightening of the traction mechanism, so as to complete the motion binding between the traction mechanism and the pipe, and enables the straightness of the extruded pipe to meet the requirements.

[0017] 2. The traction mechanism of the present invention is used in cooperation with the extrusion die. The speed of the traction mechanism matches the speed of the pipe extrusion forming. The operation of the telescopic oil cylinder is triggered by the pressure sensor, and it can quickly and automatically complete the processing of aluminum alloy pipes.

[0018] 3. The traction mechanism of the present invention is stable and reliable. The outer sides of the left and right clamping teeth are tooth-shaped structures, which can firmly fix the aluminum alloy pipe. Description of the Drawings

[0019] Figure 1 is the schematic diagram of the first step of piercing the piercing needle for the aluminum alloy pipe forming of the present invention;

[0020] Figure 2It is a schematic diagram of upsetting the blank in the second step of forming the aluminum alloy pipe of the present invention;

[0021] Figure 3 It is a schematic diagram of the aluminum alloy pipe coming out of the die in the third step of forming the aluminum alloy pipe of the present invention;

[0022] Figure 4 It is a schematic diagram of traction and extrusion by the traction machine in the fourth step of forming the aluminum alloy pipe of the present invention;

[0023] Figure 5 It is a schematic diagram of the end of extrusion in the fifth step of forming the aluminum alloy pipe of the present invention;

[0024] Figure 6 It is a general schematic diagram of the assembly of the traction mechanism of the present invention;

[0025] Figure 7 It is a schematic diagram of the base of the traction mechanism of the present invention;

[0026] Figure 8 It is a schematic diagram of the protective cover of the traction mechanism of the present invention;

[0027] Figure 9 It is a schematic diagram of the guide post of the traction mechanism of the present invention;

[0028] Figure 10 It is a schematic diagram of the driving block of the traction mechanism of the present invention;

[0029] Figure 11 It is a schematic diagram of the pull rod of the traction mechanism of the present invention;

[0030] Figure 12 It is a schematic diagram of the engaging teeth of the traction mechanism of the present invention;

[0031] Figure 13 It is a schematic diagram of the bushing of the traction mechanism of the present invention;

[0032] Among them, 1 - base 1, 2 - protective cover, 3 - guide post, 4 - driving block, 5 - pull rod, 6 - bushing, 7 - left clamping tooth, 8 - right clamping tooth, 9 - bolt, 10 - spring, 11 - spring guide post, 12 - spring sheath, 101 - extrusion rod, 102 - aluminum alloy ingot, 103 - extrusion pad, 104 - extrusion die, 105 - needle-passing hole, 106 - extrusion cylinder, 107 - traction mechanism, 108 - aluminum alloy pipe. Specific Embodiments

[0033] This part is an embodiment of the present invention, used to explain and illustrate the technical solution of the present invention. Without conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0034] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicating directions or positional relationships are the azimuth or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or case referred to must have a specific azimuth, be constructed and operated in a specific azimuth, and therefore should not be construed as a limitation to the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly indicating the quantity of the technical features indicated. Thus, the features defined with "first", "second", etc. may explicitly or implicitly include more than one such feature. In the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more.

[0035] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installed", "connected", "connected" shall be interpreted in a broad sense. For example, it may be a fixed connection, a detachable connection or an integral connection; it may be a mechanical connection or a point connection; it may be a direct connection or an indirect connection through an intermediate medium, and it may be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood through specific circumstances.

[0036] The present invention will be described in detail below with reference to the drawings and in conjunction with the embodiments.

[0037] The working principle of the present invention is as follows: Under the downward movement of the extrusion rod 101, the aluminum alloy ingot 102 is extruded from the die hole of the pipe with a piercing hole 105 under the dual action of the extrusion pad 103 and the extrusion die 104 to form a pipe shape, which is an aluminum alloy pipe.

[0038] A traction mechanism is provided below the die hole of the pipe. The traction expansion head of the traction mechanism is aligned with the die hole of the pipe. The aluminum alloy pipe moves downward outside the guide post 3 under the guidance of the guide post 3. Then, after the pipe end contacts the protective cover 2, it drives the protective cover 2 to move downward. When the bottom of the protective cover 2 contacts the pressure sensor provided on the convex edge of the bottom plate 1, the pressure sensor emits a signal. After receiving the signal emitted by the pressure sensor, the controller controls the movement of the telescopic oil cylinder in the extended state.

[0039] After receiving the control signal, the telescopic oil cylinder starts to contract. Since the top of the telescopic rod is fixedly connected to the pull rod 5, the pull rod 5 will also move downward. When the pull rod 5 moves downward, it drives the guide post 3 and the driving block 4 to move downward simultaneously. At this time, the guide post 3 and the driving block 4 move downward relative to the base 3. The pull rod 5 supports the driving block 4, and the upper surface of the driving block 4 is in surface contact with the serrated teeth surface. The serrated teeth achieve the process of outer diameter change through the dovetail groove on the base 1. There are protruding ribs on the lower inclined surface of the serrated teeth, and the protruding ribs are stuck into the dovetail groove and slide obliquely to complete the contraction and expansion of the serrated teeth, thereby fixing the end of the aluminum alloy pipe.

[0040] At this time, the telescopic rod continues to move downward, and the driving block 4 drives the base 1 to move downward together, and the entire traction head moves downward together with the aluminum alloy pipe. Due to the extremely high straightness of the movement direction of the telescopic rod of the telescopic oil cylinder, the formed aluminum alloy pipe also has extremely high straightness.

[0041] A head-end traction high-precision aluminum alloy pipe hot extrusion forming method uses the extrusion method to extrude aluminum alloy billets into aluminum alloy pipes. The pipe outlet hole is arranged directly below the extrusion equipment. A traction mechanism is arranged outside the pipe outlet hole. After the aluminum alloy pipe extends out of the pipe outlet hole and contacts the traction mechanism, the traction mechanism automatically locks the end of the aluminum alloy pipe and moves vertically downward in cooperation with the extrusion speed of the aluminum alloy pipe to ensure the straightness of the aluminum alloy pipe.

[0042] Before extrusion, first heat the aluminum alloy billet to 420 - 430 °C and keep it warm for at least 30 minutes, and heat the extrusion die to 430 - 440 °C and keep it warm for at least 30 minutes.

[0043] A traction mechanism used in a head-end traction high-precision aluminum alloy pipe hot extrusion forming method includes a traction head and a telescopic oil cylinder. The telescopic oil cylinder is arranged directly below the pipe outlet hole. The telescopic rod of the telescopic oil cylinder extends vertically upward outside the pipe outlet hole, and the top of the telescopic rod is installed with a traction head. The traction head automatically expands and tightens and fixes from the inner wall of the aluminum alloy pipe after contacting the aluminum alloy pipe.

[0044] The initial state of the telescopic oil cylinder is the maximum extended state. After the traction head expands and tightens and fixes the aluminum alloy pipe, the telescopic rod of the telescopic oil cylinder gradually contracts to the minimum contraction state; the telescopic distance of the telescopic oil cylinder matches the length of the aluminum alloy pipe.

[0045] The traction expander includes a base 1, a pull rod 5, a driving block 4, a left clamping tooth 7, a right clamping tooth 8 and a pressure sensor. The base 1 has a structure with left and right double inclined planes at the top and a through hole inside. The pull rod 5 passes through the internal through hole of the base 1 and its bottom is connected to the end of the telescopic rod of the telescopic oil cylinder. A fixed driving block 4 is installed on the pull rod 5. The driving block 4 is arranged above the base 1. The left clamping tooth 7 and the right clamping tooth 8 are respectively installed on the left and right sides of the driving block 4. The tops of the left clamping tooth 7 and the right clamping tooth 8 are rotatably connected to the upper end of the pull rod 5. The lower parts of the left clamping tooth 7 and the right clamping tooth 8 are inclined planes and are placed on the left and right double inclined planes of the base 1.

[0046] It further includes a guide post 3. The guide post 3 is fixedly connected to the top of the pull rod 5. The left clamping tooth 7 and the right clamping tooth 8 are respectively rotatably connected to the left and right sides of the guide post 3.

[0047] The top of the guide post 3 is an arc body, and the guide post 3 faces the die hole of the pipe.

[0048] The left and right double inclined planes at the top of the base 1 are specifically two inclined dovetail grooves. The lower halves of the left clamping tooth 7 and the right clamping tooth 8 are respectively arranged in the two inclined dovetail grooves; the middle sections of the left clamping tooth 7 and the right clamping tooth 8 have grooves, and the driving block 4 is stuck at the grooves of the left clamping tooth 7 and the right clamping tooth 8.

[0049] It further includes a protective cover 2. The bottom of the base 1 has a convex edge. The protective cover 2 is an annular ring sleeved outside the base 1 and above the convex edge; wherein, a spring 10 is arranged between the protective cover 2 and the convex edge of the base 1. The pressure sensor is arranged on the convex edge of the base 1; when the pressure sensor detects the touch at the bottom of the protective cover 2, the telescopic rod of the telescopic oil cylinder starts to contract.

[0050] The pipe forming process of the present invention is in sequence: piercing by the piercing needle → descending of the extrusion rod → upsetting of the blank → pipe out of the die → expansion of the traction machine → traction and extrusion by the traction machine → end of extrusion.

[0051] The traction mechanism is assembled by a base, a protective cover, a guide post, a driving block, a pull rod, a bushing and an inserted tooth.

[0052] The release and tensioning of the traction mechanism control the up and down movement of the pull rod through compressed air. The pull rod supports the driving block. The upper surface of the driving block is in surface contact with the surface of the inserted tooth. The inserted tooth reaches the process of outer diameter change through the dovetail groove on the base.

Claims

1. A traction mechanism used in a hot extrusion forming method for high-precision aluminum alloy tubes with head-end traction, characterized in that, It includes a traction expanding head and a telescopic oil cylinder. The telescopic oil cylinder is arranged directly below the die hole of the pipe. The telescopic rod of the telescopic oil cylinder extends vertically upward outside the die hole of the pipe, and the traction expanding head is installed at the top of the telescopic rod. The traction expanding head automatically expands and tightens and fixes from the inner wall of the aluminum alloy pipe after contacting the aluminum alloy pipe. The traction expanding head includes a base (1), a pull rod (5), a driving block (4), a left clamping tooth (7), a right clamping tooth (8) and a pressure sensor. The base (1) has a structure with left and right double inclined planes at the top and a through hole inside. The pull rod (5) passes through the internal through hole of the base (1) and is connected to the end of the telescopic rod of the telescopic oil cylinder at the bottom. A fixed driving block (4) is installed on the pull rod (5). The driving block (4) is arranged above the base (1). The left clamping tooth (7) and the right clamping tooth (8) are respectively installed on the left and right sides of the driving block (4). The tops of the left clamping tooth (7) and the right clamping tooth (8) are rotatably connected to the upper end of the pull rod (5). The lower parts of the left clamping tooth (7) and the right clamping tooth (8) are inclined planes and are placed on the left and right double inclined planes of the base (1).

2. The traction mechanism used in the hot extrusion forming method of a high-precision aluminum alloy pipe with head-end traction according to claim 1, characterized in that, The initial state of the telescopic oil cylinder is the maximum extended state. After the traction expanding head tightens and fixes the aluminum alloy pipe, the telescopic rod of the telescopic oil cylinder gradually contracts to the minimum contracted state; the telescopic distance of the telescopic oil cylinder matches the length of the aluminum alloy pipe.

3. The traction mechanism used in the hot extrusion forming method of a head-end traction high-precision aluminum alloy pipe according to claim 1, characterized in that, It also includes a guide post (3). The guide post (3) is fixedly connected to the top of the pull rod (5). The left clamping tooth (7) and the right clamping tooth (8) are respectively rotatably connected to the left and right sides of the guide post (3).

4. The traction mechanism used in the hot extrusion forming method of a head-end traction high-precision aluminum alloy pipe according to claim 3, characterized in that, The top of the guide post (3) is an arc body, and the guide post (3) is directly opposite to the die hole of the pipe.

5. The traction mechanism used in the hot extrusion forming method of a high-precision aluminum alloy pipe with head-end traction according to claim 3, characterized in that, The left and right double inclined planes at the top of the base (1) are specifically two inclined dovetail grooves. The lower halves of the left clamping tooth (7) and the right clamping tooth (8) are respectively arranged in the two inclined dovetail grooves; there are grooves in the middle sections of the left clamping tooth (7) and the right clamping tooth (8), and the driving block (4) is stuck at the grooves of the left clamping tooth (7) and the right clamping tooth (8).

6. The traction mechanism used in the hot extrusion forming method of a high-precision aluminum alloy pipe with head-end traction according to claim 3, characterized in that, It also includes a protective cover (2). The bottom of the base (1) has a convex edge. The protective cover (2) is an annular ring sleeved outside the base (1) and above the convex edge; among them, a spring (10) is arranged between the protective cover (2) and the convex edge of the base (1). The pressure sensor is arranged on the convex edge of the base (1); when the pressure sensor detects the touch at the bottom of the protective cover (2), the telescopic rod of the telescopic oil cylinder starts to contract.

7. A hot extrusion forming method for a head-end traction high-precision aluminum alloy pipe, using a traction mechanism used in the hot extrusion forming method for a head-end traction high-precision aluminum alloy pipe as described in claim 1, characterized in that, The extrusion method is used to extrude the aluminum alloy ingot to produce the aluminum alloy pipe. The die hole of the pipe is arranged directly below the extrusion equipment. A traction mechanism is arranged outside the die hole of the pipe. After the aluminum alloy pipe extends out of the die hole of the pipe and contacts the traction mechanism, the traction mechanism automatically locks the end of the aluminum alloy pipe and moves vertically downward in cooperation with the extrusion speed of the aluminum alloy pipe to ensure the straightness of the aluminum alloy pipe.

8. A hot extrusion forming method for a high-precision aluminum alloy pipe with head-end traction according to claim 7, characterized in that Before extrusion, first heat the aluminum alloy ingot to 420 - 430 °C and keep it warm for at least 30 minutes, and heat the extrusion die to 430 - 440 °C and keep it warm for at least 30 minutes.

Images