CN115415474B - Cold extrusion process for high-hardness blind hole internal spline - Google Patents
Cold extrusion process for high-hardness blind hole internal spline Download PDFInfo
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- CN115415474B CN115415474B CN202211079314.6A CN202211079314A CN115415474B CN 115415474 B CN115415474 B CN 115415474B CN 202211079314 A CN202211079314 A CN 202211079314A CN 115415474 B CN115415474 B CN 115415474B
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- 238000000641 cold extrusion Methods 0.000 title claims abstract description 42
- 238000000034 method Methods 0.000 title claims abstract description 36
- 230000008569 process Effects 0.000 title claims abstract description 35
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 45
- 238000001125 extrusion Methods 0.000 claims abstract description 15
- 230000007246 mechanism Effects 0.000 claims description 75
- 238000001816 cooling Methods 0.000 claims description 20
- 238000001514 detection method Methods 0.000 claims description 13
- 238000013461 design Methods 0.000 claims description 9
- 238000003825 pressing Methods 0.000 claims description 3
- 239000000463 material Substances 0.000 abstract description 12
- 238000012797 qualification Methods 0.000 abstract description 4
- 230000009286 beneficial effect Effects 0.000 abstract description 3
- 230000000903 blocking effect Effects 0.000 abstract description 2
- 238000012545 processing Methods 0.000 description 12
- 238000010862 gear shaping Methods 0.000 description 5
- 230000000694 effects Effects 0.000 description 4
- 239000007789 gas Substances 0.000 description 4
- 238000000137 annealing Methods 0.000 description 3
- 230000005540 biological transmission Effects 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 230000003028 elevating effect Effects 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 238000009434 installation Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012546 transfer Methods 0.000 description 2
- 230000009471 action Effects 0.000 description 1
- 230000006978 adaptation Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 239000005457 ice water Substances 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 238000010791 quenching Methods 0.000 description 1
- 230000000171 quenching effect Effects 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 238000005496 tempering Methods 0.000 description 1
- 239000002918 waste heat Substances 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21K—MAKING FORGED OR PRESSED METAL PRODUCTS, e.g. HORSE-SHOES, RIVETS, BOLTS OR WHEELS
- B21K1/00—Making machine elements
- B21K1/06—Making machine elements axles or shafts
- B21K1/066—Making machine elements axles or shafts splined
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21J—FORGING; HAMMERING; PRESSING METAL; RIVETING; FORGE FURNACES
- B21J13/00—Details of machines for forging, pressing, or hammering
- B21J13/02—Dies or mountings therefor
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21J—FORGING; HAMMERING; PRESSING METAL; RIVETING; FORGE FURNACES
- B21J13/00—Details of machines for forging, pressing, or hammering
- B21J13/08—Accessories for handling work or tools
- B21J13/10—Manipulators
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21J—FORGING; HAMMERING; PRESSING METAL; RIVETING; FORGE FURNACES
- B21J9/00—Forging presses
- B21J9/02—Special design or construction
- B21J9/06—Swaging presses; Upsetting presses
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21J—FORGING; HAMMERING; PRESSING METAL; RIVETING; FORGE FURNACES
- B21J9/00—Forging presses
- B21J9/10—Drives for forging presses
- B21J9/18—Drives for forging presses operated by making use of gearing mechanisms, e.g. levers, spindles, crankshafts, eccentrics, toggle-levers, rack bars
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21K—MAKING FORGED OR PRESSED METAL PRODUCTS, e.g. HORSE-SHOES, RIVETS, BOLTS OR WHEELS
- B21K29/00—Arrangements for heating or cooling during processing
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Forging (AREA)
Abstract
The invention relates to a high-hardness blind hole internal spline cold extrusion process, which comprises the steps of adding water into a blind hole of a spline shaft, then extruding, wherein in the cold extrusion process, the water is extruded by a die and flows outwards along a gap between the die and the inner wall of the blind hole to form a water film, the die is separated from the inner wall of the blind hole, meanwhile, the water absorbs heat, part of water is evaporated into water vapor, and a gas film is formed in the gap between the die and the inner wall of the blind hole. According to the invention, water is added into the blind hole of the spline shaft, so that heat generated in the extrusion process is absorbed by the water, and the temperature of the die can be prevented from being too high, thereby slowing down the rate of reducing the hardness of the die and being beneficial to prolonging the service life of the die. In the extrusion process, water flows out between the die and the inner wall of the blind hole after being extruded, plays a role in blocking the die and the inner wall of the blind hole, prevents materials on the inner wall of the blind hole of the spline shaft from being adhered to the die, can effectively avoid the conditions that the die is provided with materials and the materials are strained, and improves the qualification rate of products.
Description
Technical Field
The invention belongs to the technical field of processing of blind hole internal splines, and particularly relates to a cold extrusion process of a high-hardness blind hole internal spline.
Background
The non-standard transmission mechanism comprises a spline shaft and a gear, wherein a blind hole is formed in one end of the spline shaft, an internal spline is arranged in the blind hole, the gear is a bevel gear, an installation shaft is arranged at one end of the gear, an external spline is arranged on the outer wall of the installation shaft, and the external spline is in interference fit with the internal spline, as shown in fig. 7.
At present, when the nonstandard transmission mechanism is manufactured, a spline shaft and a gear are respectively machined and then assembled. In the processing process of the spline shaft, firstly, the outer circle, the inner hole and the like are processed to the requirements, and then the internal spline of the blind hole is processed. The common processing mode of the blind hole internal spline is cold extrusion, the efficiency is high, but the design requirement of the spline shaft is quenched and tempered HB250, quenching and tempering are carried out before rough machining, the hardness of quenched and tempered materials is high, if a cold extrusion forming mode is adopted, the forming is difficult, the conditions that the extruded die is provided with materials and the materials are damaged by pulling often occur, the product is scrapped, and meanwhile, the service life of the die is shorter. Therefore, for the spline shaft with high hardness, the internal spline of the blind hole can be processed only through gear shaping, but the gear shaping processing period is long, and the cutter cost and the tool manufacturing cost are high.
In addition, after the processing of the blind hole internal spline of the spline shaft is completed, the blind hole internal spline is required to be transferred to an assembly station to be assembled with a gear, and pressure equipment is also required for the interference fit assembly, so that the number of required equipment is large.
Disclosure of Invention
The invention aims to solve the technical problems of low gear shaping processing efficiency and high cost, and provides a cold extrusion process for high-hardness blind hole internal splines, which can prevent the die from being damaged by belt materials and products, ensure the qualification rate of the products and prolong the service life of the die.
In order to solve the problems, the invention adopts the following technical scheme: the cold extrusion process of the high-hardness blind hole internal spline comprises the steps of adding water into a blind hole of a spline shaft, then extruding again, extruding the water in the cold extrusion process by a die to outwards flow along a gap between the die and the inner wall of the blind hole to form a water film, separating the die from the inner wall of the blind hole, absorbing heat by the water, evaporating part of the water into water vapor, and forming a gas film in the gap between the die and the inner wall of the blind hole.
Further, the die comprises a lower die and an upper die, a cavity is arranged in the lower die, a vertical die core is arranged in the upper die, the die core is coaxial with the cavity, and forming teeth are arranged on the outer wall of the lower end of the die core;
During cold extrusion, the spline shaft is placed in the cavity, water is added into the blind hole of the spline shaft, then the upper die is pushed by the extruder to move downwards, the die core enters the blind hole of the spline shaft, and forming teeth on the outer wall of the die core extrude the inner wall of the blind hole to form the internal spline.
Further, the die is fixedly arranged on a horizontal supporting platform, a first station, a second station and a third station are arranged on the supporting platform, and the extruder is positioned at the third station; the upper surface of the supporting platform is provided with a pair of sliding grooves for connecting the first station, the second station and the third station, the bottom of the die is provided with a sliding block, the sliding block is positioned in the sliding groove and is in sliding fit with the sliding groove, and the die is connected with a driving mechanism for driving the die to slide along the sliding groove; the second station is provided with an upper die dismounting mechanism; the upper surface of the lower die is provided with a positioning groove, and the diameter of the positioning groove is matched with the outer diameter of the gear;
the cold extrusion process is as follows:
S1, placing a spline shaft into a cavity at a first station;
s2, driving the die to move to a second station by using a driving mechanism, and mounting an upper die on a lower die by using an upper die dismounting mechanism;
S3, driving the die to move to a third station by using a driving mechanism, and pushing the upper die to move downwards by using the extruder to form an internal spline;
s4, driving the die to move to a second station by using a driving mechanism, and taking down the upper die by using an upper die dismounting mechanism;
s5, driving the die to move to the first station by using the driving mechanism, and placing the gear in a positioning groove of the lower die to ensure that an external spline of the gear is aligned with an internal spline of the spline shaft;
s6, driving the die to move to a third station by using a driving mechanism, and pressing the external spline of the gear into the internal spline of the spline shaft by using the extruder to finish assembly;
S7, driving the die to move to the first station by using the driving mechanism, and taking out the workpiece.
Further, an ejection mechanism is arranged below the supporting platform of the first station, and in step S7, the workpiece is ejected by the ejection mechanism.
Further, a cooling air pump is arranged beside the upper die dismounting mechanism, the cooling air pump is connected with a plurality of cooling air pipes, and in the step S4, the upper die dismounting mechanism is used for cooling the die core after taking down the upper die, and the cooling air pump drives cold air to blow to the die core.
Further, go up mould dismouting mechanism including setting up first stand and the second stand in supporting platform both sides, the top of first stand and second stand is provided with horizontal supporting beam, be provided with vertical elevating system on the supporting beam, elevating system's lower extreme is connected with the clamping jaw subassembly.
Further, the upper surface of lower mould is provided with many guide posts, go up the mould be provided with a plurality of with guide post sliding fit's guiding hole, the upper end of guide post is the round platform shape.
Further, the lifting mechanism is a hydraulic cylinder, the clamping jaw assembly comprises at least three clamping jaws, a vertical cylinder is fixedly arranged at the lower end of a piston rod of the hydraulic cylinder, a sleeve is fixedly arranged outside the piston rod of the hydraulic cylinder, the upper end of the clamping jaw assembly is hinged with the sleeve, a plurality of diagonal draw bars are hinged to the piston rod of the cylinder, and the lower end of each diagonal draw bar is hinged with one clamping jaw.
Further, the driving mechanism comprises a servo driving motor and a screw rod, a sliding seat which is in sliding fit with the supporting platform is arranged on the supporting platform, a positioning hole is formed in the sliding seat, the positioning hole extends from the upper surface to the lower surface, the lower die is located in the positioning hole, the screw rod penetrates through the sliding seat and is in threaded fit with the sliding seat, and one end of the screw rod is connected with the servo driving motor.
Further, in step S5, after the die moves to the first station, detecting whether the size of the internal spline of the blind hole meets the design requirement or not by using a standard component, wherein the standard component comprises a disc body, a detection shaft is arranged on the lower surface of the disc body, a plurality of standard keys are arranged on the outer wall of the detection shaft, and a horizontal indicating mechanism is arranged on the upper surface of the disc body;
When in detection, a standard key on the detection shaft is aligned with the blind hole internal spline, the standard component is moved downwards, if the standard component can be moved to a target position, and the level degree of the display disc body of the level indicating mechanism meets the requirement, the size of the blind hole internal spline meets the design requirement, and the follow-up operation is carried out; otherwise, the requirement is not met, the spline shaft is taken out, and step S1 is carried out.
The beneficial effects of the invention are as follows: 1. in the cold extrusion process, as the hardness of the spline shaft is high and the resistance is high, the extrusion temperature is continuously increased, so that the temperature of the die is higher, the temperature of the die is reduced after extrusion and demolding, the annealing-like process is carried out, the hardness of the die is continuously reduced due to annealing, the forming difficulty is further increased, and the service life is reduced. According to the invention, water is added into the blind hole of the spline shaft, so that heat generated in the extrusion process is absorbed by the water, and the temperature of the die can be prevented from being too high, thereby slowing down the rate of reducing the hardness of the die and being beneficial to prolonging the service life of the die.
2. In the extrusion process, water flows out between the die and the inner wall of the blind hole after being extruded, plays a role in blocking the die and the inner wall of the blind hole, prevents materials on the inner wall of the blind hole of the spline shaft from being adhered to the die, can effectively avoid the conditions that the die is provided with materials and the materials are strained, and improves the qualification rate of products. In addition, the water absorbs heat and evaporates into a gas state, is discharged outwards after being pressed, and can form a gas film between the die and the inner wall of the blind hole, so that the device has a good isolation effect.
3. Compared with gear shaping, the cold extrusion processing of the invention has high efficiency and low cost.
Drawings
FIG. 1 is a schematic diagram of a mold of the present invention;
FIG. 2 is a schematic overall front view of the present invention;
FIG. 3 is a schematic cross-sectional view of A-A of FIG. 2;
FIG. 4 is a schematic cross-sectional view of B-B of FIG. 2;
FIG. 5 is a schematic cross-sectional view of C-C of FIG. 2;
FIG. 6 is a schematic illustration of a standard;
FIG. 7 is a schematic illustration of a machined spline shaft;
FIG. 8 is a schematic view of a gear engaged with a spline shaft;
Reference numerals: 1-a lower die; 2-upper die; 3-a cavity; 4, a mold core; 5-a supporting platform; 6, a chute; 7-a sliding block; 8-an ejection mechanism; 9, a cooling air pump; 10-an extruder; 11-cooling air pipes; 12-a first upright; 13-a second upright; 14-supporting the cross beam; 15-a lifting mechanism; 16-a jaw assembly; 17-a servo drive motor; 18-a screw rod; 19-a slide; 20-a guide post; 21-a tray body; 22-a detection axis; 23-standard bond; 24-clamping jaw; 25-cylinder; 26-sleeve; 27-diagonal draw bar.
Detailed Description
The invention will be further described with reference to the drawings and examples.
According to the cold extrusion process of the high-hardness blind hole internal spline, water is added into the blind hole of the spline shaft, then extrusion is carried out, in the cold extrusion process, the water is extruded by the die and flows outwards along a gap between the die and the inner wall of the blind hole to form a water film, the die and the inner wall of the blind hole are separated, meanwhile, the water absorbs heat, part of water is evaporated into water vapor, and a gas film is formed in the gap between the die and the inner wall of the blind hole.
Before processing the internal spline of the blind hole, the spline shaft is quenched and tempered to have the hardness of HB240-260, then is machined, and is subjected to cold extrusion after forming the excircle, the blind hole and the like. Because the spline shaft has high hardness, the resistance is large during extrusion, a large amount of heat is generated during extrusion, the temperature of the die is increased, the hardness of the die is reduced after the temperature is increased, in addition, the die is subjected to a similar annealing process after the temperature is increased, the hardness of the die is reduced due to annealing, and therefore the service life of the die is short.
The blind hole of the spline shaft is filled with the hot water or the ice water, so that heat generated in the extrusion process can be absorbed, the cooling effect is achieved, the phenomenon that the hardness is reduced due to overhigh temperature of the die is avoided, and part of water absorbs heat and is evaporated into gaseous water vapor. Because the cold extrusion process is that the die moves from the orifice of the blind hole to the bottom of the blind hole gradually, before extrusion is finished, water always exists in the blind hole, along with the extrusion, the water in the blind hole can continuously flow outwards, and the generated heat is taken away, so that continuous cooling can be realized, and the cooling effect is better. Secondly, water and steam must follow the outside flow between mould and the blind hole inner wall after receiving the extrusion of mould to form water film and air film between mould and blind hole inner wall, certainly because the size error of integral key shaft and mould, the clearance size of mould and blind hole inner wall can not evenly distributed, consequently water film and air film are difficult to evenly distributed, partial position probably does not have water film and air film, but must form water film and air film in partial position at least, can play certain separation effect, separate mould and blind hole inner wall, can prevent the material adhesion of blind hole inner wall on the mould, thereby solved mould area material, the problem of product strain, the qualification rate of improvement product.
At present, blind hole internal spline cold extrusion dies are various, and the prior art can be directly adopted as a preferred embodiment of the invention: as shown in fig. 1, the mold comprises a lower mold 1 and an upper mold 2, a cavity 3 is arranged in the lower mold 1, a vertical mold core 4 is arranged in the upper mold 2, the mold core 4 is coaxial with the cavity 3, and forming teeth are arranged on the outer wall of the lower end of the mold core 4.
The forming teeth are used for forming the blind hole internal spline, and the size, the shape and the like of the forming teeth are the same as those of the blind hole internal spline. The cavity 3 is sized and shaped to fit the spline shaft for positioning the spline shaft. During cold extrusion, the spline shaft is vertically placed into the cavity 3, the spline shaft is kept stable, then water is added into the blind hole of the spline shaft, the upper die 2 is pushed to move downwards by the extruder 10, the die core 4 enters the blind hole of the spline shaft, and forming teeth on the outer wall of the die core 4 extrude the inner wall of the blind hole to form an internal spline. The extruder 10 may be a cold extrusion device commonly used in the art.
The cold extrusion process can enable the precision of the spline in the blind hole to reach IT8 level, completely meets the design requirement, and can assemble the spline shaft and the gear after cold extrusion is completed. The current assembly mode is: after the spline shaft is taken out from the lower die 1, the spline shaft is transferred to an assembly station, and the spline shaft and the gear are in interference fit, so that the gear needs to be pressed into the spline shaft by a press machine. This mode needs to occupy great workshop area to need transfer equipment, press etc. equipment is more, and assembly efficiency is lower. Because the working process of the press machine required by assembly and the working process of the extruder 10 adopted by cold extrusion are basically the same, in order to solve the problems, the cold extrusion process, the assembly process and the like of the blind hole internal spline are carried out on the same equipment, namely, the blind hole internal spline is extruded and formed by the extruder 10, and then the gear is pressed and assembled into the spline shaft by the extruder 10, so that the press machine can be saved, the equipment cost is saved, the occupied area is saved, and the transfer distance is shortened. In addition, during assembly, the mold core 4 does not need to work, and can be sufficiently cooled, and the mold core 4 works again after assembly. The mold core 4 intermittently works, so that the service life of the mold core 4 is prolonged while the overall production efficiency is ensured.
Specifically, as shown in fig. 2 to 5, the mold is disposed on a horizontal support platform 5, and the support platform 5 may be a rectangular metal plate with a larger thickness, and is supported by support legs, so that the support platform 5 is at a proper height.
The support platform 5 is provided with a first station, a second station and a third station, the first station, the second station and the third station are sequentially arranged along the length direction of the support platform 5, and the extruder 10 is located at the third station. At the first station, the spline shaft can be put into the cavity 3, the gear can be put into the lower die 1, and the assembled spline shaft can be taken out, at the second station, the upper die 2 can be taken down and installed, and at the third station, cold extrusion and assembly can be performed.
The upper surface of supporting platform 5 is provided with a pair of spout 6 of connecting first station, second station and third station, and the bottom of mould is provided with slider 7, and slider 7 is located spout 6 and with spout 6 sliding fit, has the interval between the lower surface of slider 7 and the tank bottom of spout 6, avoids the pressure transmission to slider 7 when cold extrusion and the assembly, but bears the pressure by lower mould 1 and supporting platform 5. The mould is connected with a driving mechanism for driving the mould to slide along the chute 6, and the driving mechanism can convey the mould to the first station, the second station and the third station.
The second station is provided with an upper die dismounting mechanism, and the upper die dismounting mechanism can take down the upper die 2 and also can remount the upper die 2 on the lower die 1. The upper surface of lower mould 1 is provided with the constant head tank, and the constant head tank is the circular slot, and the diameter of constant head tank and the external diameter adaptation of gear, and the constant head tank is coaxial with die cavity 3, can fix a position the gear for the gear is coaxial with the integral key shaft during the assembly.
The cold extrusion process is as follows:
s1, placing the spline shaft into the cavity 3 at a first station.
S2, driving the die to move to a second station by using a driving mechanism, and mounting the upper die 2 on the lower die 1 by using an upper die dismounting mechanism to ensure that the die core 4 and the die cavity 3 are coaxial.
The upper die dismounting mechanism can be a manipulator, and preferably comprises a first upright post 12 and a second upright post 13 which are arranged on two sides of the supporting platform 5, wherein the tops of the first upright post 12 and the second upright post 13 are provided with a horizontal supporting cross beam 14, the supporting cross beam 14 is provided with a vertical lifting mechanism 15, and the lower end of the lifting mechanism 15 is connected with a clamping jaw assembly 16. The clamping jaw assembly 16 can clamp the edge of the upper die 2, and then the lifting mechanism 15 drives the clamping jaw assembly 16 to move downwards, so that the upper die 2 can be placed on the lower die 1.
The lifting mechanism 15 may be a hydraulic cylinder, the clamping jaw assembly 16 comprises at least three clamping jaws 24, a vertical air cylinder 25 is fixedly arranged at the lower end of a piston rod of the hydraulic cylinder, a sleeve 26 is fixedly arranged outside the piston rod of the hydraulic cylinder, the upper end of the clamping jaw assembly 16 is hinged with the sleeve 26, a plurality of diagonal draw bars 27 are hinged with the piston rod of the air cylinder 25, and the lower end of each diagonal draw bar 27 is hinged with one clamping jaw 24. When the piston rod of the air cylinder 25 moves downward, each diagonal draw bar 27 is pushed to rotate, and the diagonal draw bars 27 push the clamping jaws 24 to move outwards, so that the clamping jaw assembly 16 is opened. When the piston rod of the air cylinder 25 moves upwards, each diagonal draw bar 27 is pulled to rotate, each clamping jaw 24 is pulled by the diagonal draw bars 27 to synchronously rotate inwards, and the lower end of each clamping jaw 24 can clamp the edge of the lower die 1.
In order to align the mold core 4 of the upper mold 2 with the cavity 3 of the lower mold 1, the upper surface of the lower mold 1 is provided with a plurality of guide posts 20, the upper mold 2 is provided with a plurality of guide holes in sliding fit with the guide posts 20, and the upper ends of the guide posts 20 are in a truncated cone shape. The guide posts 20 play a role in guiding and positioning, and when a plurality of guide posts 20 are matched with corresponding guide holes one by one, the mold core 4 of the upper mold 2 and the mold cavity 3 of the lower mold 1 can be ensured to be coaxial.
S3, driving the die to move to a third station by using a driving mechanism, filling water into the blind hole of the spline shaft, pushing the upper die 2 to move downwards by using the extruder 10, and forming an internal spline; the ram of the extruder 10 is then moved upward and out of the upper die 2.
S4, driving the die to move to the second station by using the driving mechanism, and taking down the upper die 2 by using the upper die dismounting mechanism. Specifically, the lifting mechanism 15 drives the clamping jaw assembly 16 to move downwards to a proper height, then the clamping jaw assembly 16 is used for clamping the edge of the upper die 2, and the lifting mechanism 15 drives the clamping jaw assembly 16 to move upwards, so that the upper die 2 can be removed.
After cold extrusion is completed, the mold core 4 of the upper mold 2 has certain waste heat, the temperature is higher than the normal temperature, a cooling air pump 9 is arranged beside the upper mold disassembly and assembly mechanism for enabling the mold core 4 to be cooled rapidly, the cooling air pump 9 is connected with a plurality of cooling air pipes 11, the cooling air pipes 11 adopt hoses, the air outlets of the cooling air pipes 11 face the mold core 4, and after the upper mold disassembly and assembly mechanism takes down the upper mold 2, the cooling air pump 9 drives nearby cold air to blow to the mold core 4 so as to cool the mold core 4.
S5, driving the die to move to the first station by using the driving mechanism, and manually placing the gear in the positioning groove of the lower die 1 to ensure that the external spline of the gear is aligned with the internal spline of the spline shaft.
S6, driving the die to move to a third station by using the driving mechanism, and pressing the external spline of the gear into the internal spline of the spline shaft by the extruder 10 to finish assembly. The ram of extruder 10 moves upward, away from the gear.
S7, driving the die to move to the first station by using the driving mechanism, and taking out the workpiece. After extrusion, the spline shaft is tightly attached to the cavity 3, and the difficulty of manually taking out the workpiece is high, so that an ejection mechanism 8 is arranged below the support platform 5 of the first station, and the workpiece is ejected by the ejection mechanism 8. The ejection mechanism 8 can be a hydraulic cylinder and the like, an opening for the ejection mechanism 8 to pass through is formed in the supporting platform 5, the ejection mechanism 8 moves upwards, and the spline shaft can be ejected by applying upward thrust to the spline shaft.
The driving mechanism comprises a servo driving motor 17 and a screw rod 18, a sliding seat 19 which is in sliding fit with the supporting platform 5 is arranged on the supporting platform 5, the sliding seat 19 is provided with a positioning hole extending from the upper surface to the lower surface, the lower die 1 is positioned in the positioning hole, the screw rod 18 penetrates through the sliding seat 19 and is in threaded fit with the sliding seat 19, and one end of the screw rod 18 is connected with the servo driving motor 17.
The servo drive motor 17 can accurately control the moving distance of the die to stop the die at a proper position. The bottom of the slide 19 may be provided with a track groove, while the upper surface of the support platform 5 may be provided with a guide rail, which is parallel to the chute 6, which is located in the track groove and which is in sliding fit with the track groove. The lower die 1 is located inside the slide 19, and when the slide 19 moves, the lower die 1 can be pushed to move. The lower die 1 is supported by the supporting platform 5, and after the lower die 1 is subjected to pressure, the lower die is not transmitted to the sliding seat 19, namely, the lower die is not transmitted to the screw rod 18, so that the screw rod 18 is prevented from being deformed. When the servo driving motor 17 rotates, the screw rod 18 is driven to rotate, and under the action of the threads, the screw rod 18 pushes the sliding seat 19 to linearly move, so that the lower die 1 inside the sliding seat 19 is driven to move.
After cold extrusion is finished, the forming precision of the internal spline of the blind hole cannot be guaranteed to completely meet the requirement, so that the formed internal spline of the blind hole is preferably detected, and the assembly is performed after the precision of the internal spline of the blind hole is confirmed to meet the requirement. Specifically, in the step S5, after the die moves to the first station, the standard component is used to detect whether the size of the internal spline of the blind hole meets the design requirement, and the standard component is shown in fig. 6, and includes a disc 21, a detection shaft 22 is disposed on the lower surface of the disc 21, a plurality of standard keys 23 are disposed on the outer wall of the detection shaft 22, and a horizontal indicating mechanism is disposed on the upper surface of the disc 21. The size and position distribution of the standard key 23 are matched with the internal spline of the blind hole, so that the standard key 23 can be in clearance fit with the internal spline of the standard blind hole. The standard key 23 has high dimensional accuracy, and if the forming accuracy of the blind hole internal spline meets the requirement, the standard key 23 can be tightly matched with the blind hole internal spline. The level indicating mechanism is used for detecting the levelness of the tray 21, and may be a bubble level or the like.
During detection, a standard key 23 on the detection shaft 22 is aligned with the blind hole internal spline and the standard component is moved downwards, and if the standard key 23 cannot enter the blind hole internal spline, the blind hole internal spline is unqualified; if the standard key 23 can enter the blind hole internal spline, continuing to move the standard component downwards, and if the standard component can move to the target position downwards and the level degree of the display disc body 21 of the level indicating mechanism meets the requirement, indicating that the size of the blind hole internal spline meets the design requirement, and carrying out subsequent operation; otherwise, the requirement is not met, the spline shaft is taken out, and step S1 is carried out. The target position is the position when the lower end of the index key 23 reaches the bottom of the internal spline of the blind hole, and is determined according to the depth of the internal spline of the blind hole. When the standard part can move downwards to the target position and the levelness of the disc body 21 also meets the requirement, the blind hole internal spline is indicated to be matched with the standard key 23, and the blind hole internal spline meets the requirement. If the standard cannot be moved down to the target position, the position of the spline part in the blind hole is not precisely formed.
The blind hole internal spline processing can be carried out on the spline shaft with the hardness reaching HB240-260 in a cold extrusion mode, compared with gear shaping processing, the blind hole internal spline processing has higher efficiency and lower cost, ensures that the forming precision of cold extrusion reaches IT8 level, completely meets the design requirement, and has high product percent of pass. In addition, the spline shaft and the gear are assembled in the cold extrusion processing procedure, the number of equipment and the occupied area are reduced, and the production cost is further reduced.
The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (6)
1. The cold extrusion process of the high-hardness blind hole internal spline is characterized in that water is firstly added into a blind hole of a spline shaft, then extrusion is carried out, in the cold extrusion process, the water is extruded by a die and flows outwards along a gap between the die and the inner wall of the blind hole to form a water film, the die is separated from the inner wall of the blind hole, meanwhile, the water absorbs heat, part of the water is evaporated into water vapor, and a gas film is formed in the gap between the die and the inner wall of the blind hole;
The die comprises a lower die (1) and an upper die (2), wherein a cavity (3) is formed in the lower die (1), a vertical die core (4) is arranged in the upper die (2), the die core (4) is coaxial with the cavity (3), and forming teeth are formed on the outer wall of the lower end of the die core (4);
during cold extrusion, the spline shaft is placed into a cavity (3), water is added into a blind hole of the spline shaft, then an extruder (10) is utilized to push an upper die (2) to move downwards, a die core (4) enters the blind hole of the spline shaft, and forming teeth on the outer wall of the die core (4) extrude the inner wall of the blind hole to form an internal spline;
the die is arranged on a horizontal supporting platform (5), a first station, a second station and a third station are arranged on the supporting platform (5), and the extruder (10) is positioned at the third station; the upper surface of the supporting platform (5) is provided with a pair of sliding grooves (6) for connecting the first station, the second station and the third station, the bottom of the die is provided with a sliding block (7), the sliding block (7) is positioned in the sliding grooves and is in sliding fit with the sliding grooves, and the die is connected with a driving mechanism for driving the die to slide along the sliding grooves (6); the second station is provided with an upper die dismounting mechanism; the upper surface of the lower die (1) is provided with a positioning groove, and the diameter of the positioning groove is matched with the outer diameter of the gear;
the cold extrusion process is as follows:
s1, placing a spline shaft into a cavity (3) at a first station;
s2, driving the die to move to a second station by using a driving mechanism, and mounting an upper die (2) on a lower die (1) by using an upper die dismounting mechanism;
s3, driving the die to move to a third station by using a driving mechanism, and pushing the upper die (2) to move downwards by using the extruder (10) to form an internal spline;
s4, driving the die to move to a second station by using a driving mechanism, and taking down the upper die (2) by using an upper die dismounting mechanism;
s5, driving the die to move to a first station by using a driving mechanism, and placing the gear in a positioning groove of a lower die (1) to ensure that an external spline of the gear is aligned with an internal spline of a spline shaft;
S6, driving the die to move to a third station by using a driving mechanism, and pressing the external spline of the gear into the internal spline of the spline shaft by using the extruder (10) to finish assembly;
S7, driving the die to move to a first station by using a driving mechanism, and taking out the workpiece;
An ejection mechanism (8) is arranged below the supporting platform (5) of the first station, and in the step S7, a workpiece is ejected out by the ejection mechanism (8);
The driving mechanism comprises a servo driving motor (17) and a screw rod (18), a sliding seat (19) which is in sliding fit with the supporting platform (5) is arranged on the supporting platform (5), the sliding seat (19) is provided with a positioning hole which extends from the upper surface to the lower surface, the lower die (1) is positioned in the positioning hole, the screw rod (18) penetrates through the sliding seat (19) and is in threaded fit with the sliding seat (19), and one end of the screw rod (18) is connected with the servo driving motor (17).
2. The cold extrusion process of the high-hardness blind hole internal spline according to claim 1, wherein a cooling air pump (9) is arranged beside the upper die dismounting mechanism, the cooling air pump (9) is connected with a plurality of cooling air pipes (11), and in step S4, the upper die dismounting mechanism is used for cooling the die core (4) by driving cold air to blow to the die core (4) after the upper die (2) is removed by the upper die dismounting mechanism.
3. The cold extrusion process of the high-hardness blind hole internal spline according to claim 1, wherein the upper die dismounting mechanism comprises a first upright (12) and a second upright (13) which are arranged on two sides of a supporting platform (5), horizontal supporting beams (14) are arranged at the tops of the first upright (12) and the second upright (13), a vertical lifting mechanism (15) is arranged on the supporting beams (14), and a clamping jaw assembly (16) is connected to the lower end of the lifting mechanism (15).
4. A high-hardness blind hole internal spline cold extrusion process as claimed in claim 3, wherein a plurality of guide posts (20) are arranged on the upper surface of the lower die (1), a plurality of guide holes which are in sliding fit with the guide posts (20) are arranged on the upper die (2), and the upper ends of the guide posts (20) are in a truncated cone shape.
5. A high-hardness blind hole internal spline cold extrusion process as claimed in claim 3, wherein the lifting mechanism (15) is a hydraulic cylinder, the clamping jaw assembly (16) comprises at least three clamping jaws (24), a vertical cylinder (25) is fixedly arranged at the lower end of a piston rod of the hydraulic cylinder, a sleeve (26) is fixedly arranged outside the piston rod of the hydraulic cylinder, the upper end of the clamping jaw assembly (16) is hinged with the sleeve (26), a plurality of diagonal tension rods (27) are hinged with the piston rod of the cylinder (25), and the lower end of each diagonal tension rod (27) is hinged with one clamping jaw (24).
6. The cold extrusion process of the high-hardness blind hole internal spline according to claim 1, wherein in the step S5, after the die moves to the first station, whether the size of the blind hole internal spline meets the design requirement is detected by using a standard component, the standard component comprises a disc body (21), a detection shaft (22) is arranged on the lower surface of the disc body (21), a plurality of standard keys (23) are arranged on the outer wall of the detection shaft (22), and a horizontal indicating mechanism is arranged on the upper surface of the disc body (21);
When in detection, a standard key (23) on a detection shaft (22) is aligned with the blind hole internal spline, the standard component is moved downwards, if the standard component can be moved to a target position, and the level degree of a display disc body (21) of a level indicating mechanism meets the requirement, the size of the blind hole internal spline meets the design requirement, and the follow-up operation is carried out; otherwise, the requirement is not met, the spline shaft is taken out, and step S1 is carried out.
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