Hot extrusion die device and method for forming micro gears

Abstract

The present invention belongs to the field of mold design, and discloses a hot extrusion mold device and method for forming micro gears. It includes a concave mold, an extrusion gasket, an extrusion needle, a push rod, an inner sleeve, and an extrusion rod. One side of the extrusion rod is an extrusion needle, and the other end of the extrusion needle is partially placed in the through hole III of the inner sleeve, and the other end of the extrusion needle is placed on one side of the through hole III. The extrusion gasket, the blank and the concave mold are also placed in the middle through hole III of the inner sleeve in sequence. The through hole III of the inner sleeve is connected to the tapered groove in the middle of the other end of the inner sleeve. One end of the push rod abuts against the tapered groove of the inner sleeve, and the push rod has a central cavity. The present invention provides a hot extrusion mold device for forming micro gears, which has the characteristics of compact structure, high mold matching accuracy, good guiding performance, low cost, and high production efficiency.

Description

Technical Field

[0001] The present invention relates to the field of mold design, and in particular to a hot extrusion mold device and method for forming micro gears. Background Art

[0002] With the development of modern science and technology, especially the rapid development of micro-machining technology and micro-electromechanical systems, and driven by the diversified needs of industrial production in the 21st century, micro-machines have also developed rapidly. The demand for micro parts is becoming more and more extensive, requiring a low-cost, high-quality, high-precision forming device that can be mass-produced.

[0003] Titanium alloys are widely used in various industrial fields due to their excellent comprehensive properties. However, the difficulty of processing titanium alloys has hindered their further development. Traditional precision processing equipment has been unable to meet these demands. Although the later developed micro-plastic forming equipment can be used to process a variety of materials, the extremely small parts still pose manufacturing difficulties for existing molds. Summary of the Invention

[0004] In response to the problems existing in the prior art, the present invention provides a hot extrusion die device and method for forming micro gears, which has the characteristics of compact structure, high mold matching precision, good guidance, low cost and high production efficiency.

[0005] The present invention is realized in this way: a hot extrusion die device for forming a micro gear comprises a guide die, a concave die, an extrusion gasket, a push rod, an extrusion rod and an inner sleeve.

[0006] One end of the extrusion rod has a stepped structure, wherein one end of the extrusion rod is a flange with two through holes I. During the extrusion process, through hole I on the flange at the end of the extrusion rod is connected to through hole II on the flange at the upper end of the inner sleeve using a dedicated wire.

[0007] The stepped structure of the extrusion rod forms an extrusion needle, with rounded corners at the transition point. The small end of the extrusion needle extends into through-hole III of the inner sleeve. Insulating cotton is placed between the extrusion rod and the extrusion needle, ensuring that current can only be conducted to the inner sleeve via the wire. A compression gasket is installed at the small end of the extrusion needle and placed in through-hole III of the inner sleeve. A funnel-shaped guide die is placed in through-hole III of the inner sleeve. A concave die, containing a working cavity for extruding the gear shape, is placed in through-hole III of the inner sleeve.

[0008] The inner sleeve is installed at one end of the push rod, and has a flange at one end of the inner sleeve with two through holes II on the flange. A through hole III is opened in the middle of one end of the inner sleeve, and through hole III is used to install extrusion gaskets, blanks, guide molds and concave molds. A tapered groove is opened in the middle of the other end of the inner sleeve, and through hole III is connected to the tapered groove. The inner wall of the tapered groove has an internal thread for connecting to the push rod. The other end of the inner sleeve is a hexagonal prism structure I.

[0009] The ejector pin is in the shape of a stepped shaft, and one end of the ejector pin is a hexagonal prism structure II. The hexagonal prism structure II facilitates the disassembly of the mold after extrusion is completed. A cavity 11 is provided in the middle of the ejector pin.

[0010] The purpose of the hexagonal prism design (I and II) is as follows: 1. The hexagonal prism design ensures precise positioning with a simple structure without the addition of other positioning and guiding mechanisms. 2. During disassembly, since there are no additional locking or guiding components, the parts can be directly pulled out, thus facilitating demolding.

[0011] One end of the push rod has a cone angle of 30 degrees, and an external thread for connecting with the inner sleeve is provided on the outer circumferential end surface on the rear side of the cone angle.

[0012] The method of the present invention comprises the following steps:

[0013] Step 1. Use the external thread on the ejector pin to connect with the internal thread of the inner sleeve, then place the die, guide die, blank, and extrusion gasket into the through hole III of the inner sleeve in sequence, and then place the extrusion needle into the through hole III of the inner sleeve.

[0014] Step 2. Place the extrusion needle into the through hole III of the inner sleeve and press the extrusion rod against the other end face of the extrusion needle against the extrusion gasket. Place insulating cotton between the contact surface of the extrusion rod and the extrusion needle to separate the extrusion rod and the extrusion needle to prevent the extrusion needle from being damaged by the force during the extrusion process. Use a special wire to connect the through hole I of the extrusion rod and the through hole II of the inner sleeve to complete the assembly of the mold.

[0015] The hot extrusion die designed in this invention heats the billet and die directly via current conduction. Insulation cotton is added between the extrusion rod and the extrusion needle to prevent the extrusion needle from generating high temperatures during heating, which could reduce its strength and cause damage during the extrusion process.

[0016] Step 3. Install the mold on a reheating simulator to heat the mold and the blank. Select the method of passing electric current to use Joule heat to heat the mold and the blank to the specified temperature at a specified heating rate. After reaching the forming temperature, keep it warm for a specified time.

[0017] Step 4. The force-applying mechanism of the thermal simulator presses onto the extrusion rod, and the pressure is transmitted to the extrusion gasket through the extrusion needle. The extrusion gasket presses the blank downward toward the guide die and transmits it to the die, causing the die to tend to move downward.

[0018] Step 5. The die is supported by the ejector pin, and the movement direction of the blank is guaranteed by the cavity of the inner sleeve. The blank transmits force to the guide die and the die. The die is supported by the ejector pin (the die is supported by the ejector pin and is fixed during the extrusion of the blank). The blank is subjected to pressure and begins to undergo plastic deformation after reaching a certain value, which can fill the cavity of the die and form a part with the same shape and size as the cavity of the die.

[0019] Step 6. After cooling, remove the extrusion needle and rotate the ejector pin out of the inner sleeve, remove the formed part, and complete the entire forming process.

[0020] The advantages and positive effects of the present invention are:

[0021] 1. This device is used on a thermal simulator. The forming process is completely controlled by the mold device structure. The precision of the formed part is guaranteed by the extrusion gasket and the die.

[0022] 2. The die and extrusion gasket are processed with high-precision processing technology, and the matching accuracy is very high.

[0023] 3. The movement of the extrusion gasket is guided by the cavity of the inner sleeve, and the die is placed on the ejector pin and fixed. The gap between the extrusion needle and the inner sleeve reduces the friction during the extrusion process, improves the efficiency of the device, saves energy, reduces costs, and also effectively protects the micro mold, giving it a longer service life.

[0024] 4. The present invention has the advantages of compact structure, high mold matching precision, good guidance, low cost, high work efficiency, simple processing technology, and can form a variety of materials.

[0025] 5. Optimize the structure of the inner sleeve of the mold. Set interfaces on the extrusion rod and the inner sleeve that can be directly connected by wires (that is, set through holes on the flange of the extrusion rod and on the flange of the inner sleeve). Use the Joule heating effect through electric current to heat the blank to improve the poor forming performance of the material at room temperature. At the same time, use the electroplastic effect to promote the forming of titanium alloy micro gears.

[0026] 6. A through hole is opened inside the inner sleeve, which is connected to the tapered groove. The tapered groove is provided with an internal thread. The ejector pin has a cavity and a 30° cone angle at the end. The outer circumferential surface on the rear side of the cone angle has an outer circumferential surface, which is connected by the external thread and the internal thread, thereby ensuring the accuracy of the mold during the high-temperature molding process, ensuring the fit of the mold assembly, and reducing the cost of repairing the mold as a whole after mold loss.

[0027] 7. Adding a guide die between the blank and the die reduces the loss of the die during the extrusion process, ensures that the high-precision die is subjected to less force during the forming process, and increases the service life of the key component die. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a structural schematic diagram of the present invention;

[0029] Figure 2 It is a schematic diagram of the structure of the concave mold of the present invention;

[0030] Figure 3 It is a schematic diagram of the inner sleeve structure of the present invention;

[0031] Figure 4 It is a schematic diagram of the top rod structure of the present invention;

[0032] Figure 5 It is a schematic diagram of the structure of the extrusion rod of the present invention;

[0033] Figure 6 It is a schematic diagram of the structure of the extruded gasket of the present invention;

[0034] Figure 7 It is a schematic diagram of the structure of the extrusion rod of the present invention;

[0035] Figure 8 It is a schematic structural diagram of the extrusion needle of the present invention.

[0036] In the figure, 1-guide die, 2-die, 3-blank, 4-extrusion gasket, 5-extrusion needle, 6-pull rod, 7-inner sleeve, 8-extrusion rod, 9-through hole I, 10-through hole II, 11-cavity, 12-hexagonal prism structure I, 13-hexagonal prism structure II, 14-external thread, 15-internal thread, 16-through hole III, 17-taper angle, 18-tapered groove, 19-insulating cotton. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0038] The application principle of the present invention is further described below with reference to specific embodiments.

[0039] like Figure 1-8 As shown, the hot extrusion die device for forming micro gears includes a guide die 1, a concave die 2, an extrusion gasket 4, a push rod 6, an extrusion rod 8, and an inner sleeve 7.

[0040] One end of the extrusion rod 8 has a stepped structure and is provided with a flange with two through-holes I9. During the extrusion process, through-holes I9 on the flange at the end of the extrusion rod 8 are connected to through-holes II10 on the flange at the upper end of the inner sleeve 7 using a dedicated wire. This conducts current and prevents current from flowing through the extrusion needle 5, which could overheat the head of the extrusion needle 5 and cause damage to the mold.

[0041] The stepped structure of the extrusion rod 8 forms an extrusion needle 5, with rounded corners at the transition point to prevent stress concentration. The small end of the extrusion needle 5 extends into the through-hole III 16 of the inner sleeve 7. Insulating cotton 19 is placed between the extrusion rod 8 and the extrusion needle 5 to block the flow of current, allowing current to be conducted only through the wires to the inner sleeve 7. A compression gasket 4 is placed at the small end of the extrusion needle 5. This separate extrusion gasket 4 is used to reduce friction when extruding the billet and prevent damage to the die. The separate structure also facilitates part replacement. The compression gasket 4 is placed in the through-hole III 16 of the inner sleeve 7. A guide die 1 is placed in the through-hole III 16 of the inner sleeve 7 and is used to feed the billet into the die 2 during the extrusion process. The guide die 1 is funnel-shaped, facilitating entry of the billet into the die during plastic flow caused by heat and extrusion (the guide die 1 is designed to be funnel-shaped). The die 2 is set in the through-hole III 16 of the inner sleeve 7 and has a working cavity for extruding the gear shape.

[0042] The extrusion gasket 4 is a separate component. When assembling the mold before extrusion begins, the extrusion gasket 4 can be directly placed therein.

[0043] The inner sleeve 7 is installed at one end of the push rod 6. A flange is provided at one end of the inner sleeve 7. The flange has two through holes Ⅱ10. A through hole Ⅲ16 is provided in the middle of one end of the inner sleeve 7. The through hole Ⅲ16 is used to install the extrusion gasket 4, the bad material 3, the guide die 1 and the die 2. A tapered groove 18 is provided in the middle of the other end of the inner sleeve 7. The through hole Ⅲ16 is connected to the tapered groove 18. The inner wall of the notch of the tapered groove 18 has an internal thread 15 for connecting with the push rod 6. The other end of the inner sleeve 7 is a hexagonal prism structure Ⅰ12. The hexagonal prism structure Ⅰ12 facilitates the disassembly of the mold after the extrusion is completed.

[0044] The ejector pin 6 is in the shape of a stepped shaft, and one end of the ejector pin 6 is a hexagonal prism structure II13. The hexagonal prism structure II13 facilitates the disassembly of the mold after extrusion is completed. The middle of the ejector pin 6 has a cavity 11 for placing the billet formed by extrusion.

[0045] The purpose of the hexagonal prism design (I and II) is as follows: 1. The hexagonal prism design ensures precise positioning with a simple structure without the addition of other positioning and guiding mechanisms. 2. During disassembly, since there are no additional locking or guiding components, the parts can be directly pulled out, thus facilitating demolding.

[0046] One end of the push rod 6 is a 30° taper angle 17 , and an outer circumferential end surface on the rear side of the taper angle 17 is provided with an external thread 14 for connecting with the inner sleeve 7 .

[0047] The method of using the present invention comprises the following steps:

[0048] Step 1. Use the external thread 14 on the push rod 6 to connect with the internal thread 15 of the inner sleeve 7, and then put the die 2, the guide die 1, the blank 3, and the extrusion gasket 4 smoothly into the through hole III16 of the inner sleeve 7 in sequence.

[0049] Step 2. Place the extrusion needle 5 into the through hole Ⅲ16 of the inner sleeve 7 and press against the extrusion gasket 4, and press the extrusion rod against the other end face of the extrusion needle installed in step 1. Insulating cotton is installed between the extrusion rod and the end face of the extrusion needle to separate the contact surface of the extrusion rod and the extrusion needle to prevent the extrusion needle from being damaged by heat when power is turned on and the extrusion needle from being damaged by force during the extrusion process. Use a special wire to connect the through hole Ⅰ9 of the extrusion rod 8 and the through hole Ⅱ10 of the inner sleeve 7 to complete the assembly of the mold.

[0050] Step 3. Install the mold on a reheating simulator to heat the mold and the blank. Select the method of passing electric current to use Joule heat to heat the mold and the blank to the specified temperature at a specified heating rate. After reaching the forming temperature, keep it warm for a specified time.

[0051] Step 4. The force-applying mechanism of the thermal simulator presses onto the extrusion rod 8, and transmits the pressure to the extrusion gasket 4 through the extrusion needle 5. The extrusion gasket 4 presses the blank 3 downward toward the guide die 1 and transmits it to the die 2, so that the die 2 tends to move downward.

[0052] Step 5. The die 2 is supported by the push rod, and the movement direction of the blank 3 is guaranteed by the cavity 6 of the inner sleeve 7. The blank transmits force to the guide die 1 and the die 2. The die 2 is supported by the push rod 6 and is fixed in the process of extruding the blank. The blank is subjected to pressure and begins to undergo plastic deformation after reaching a certain value, which can fill the cavity of the die 2 and form a part with the same shape and size as the cavity of the die 2.

[0053] Step 6. After cooling, remove the extrusion needle 5 and rotate the ejector pin 6 out of the inner sleeve 7, take out the formed part, and complete the entire forming process.

[0054] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A hot extrusion die device for forming a micro gear, comprising a concave die, an extrusion gasket, an extrusion needle, a push rod, an inner sleeve, and an extrusion rod, characterized in that: One side of the extrusion rod is an extrusion needle, and the other end part of the extrusion needle is placed in the through hole III of the inner sleeve. The extrusion gasket, the blank and the die are also placed in the middle through hole III of the inner sleeve in sequence. The through hole III of the inner sleeve is connected to the tapered groove in the middle of the other end of the inner sleeve. One end of the push rod is against the tapered groove of the inner sleeve. The push rod has a central cavity, and the inner circumferential notch of the inner tapered groove has an internal thread. One end of the push rod is a 30-degree cone angle, and the outer circumferential surface behind the 30-degree cone angle has an external thread. The inner sleeve is connected to the external thread of the push rod through the internal thread. The die has a working cavity for extruding a gear shape. A guide die is also provided between the blank and the die. The guide die is placed in the through hole III of the inner sleeve and is funnel-shaped. Insulating cotton is provided between the extrusion rod and the extrusion needle. Among them, the method for using the hot extrusion die device for forming a micro gear comprises the following steps: Step 1. Use the external thread on the ejector pin to connect with the internal thread of the inner sleeve, and then put the die, guide die, blank, and extrusion gasket into the through hole III of the inner sleeve in order, and then put the extrusion needle into the through hole III of the inner sleeve; Step 2. Place the extrusion needle into the through hole III of the inner sleeve and against the extrusion gasket, place the extrusion rod against the other end face of the extrusion needle installed in step 1, install insulating cotton between the extrusion rod and the end face against which the extrusion needle abuts, to separate the contact surface of the extrusion rod from the extrusion needle, and connect the through hole I of the extrusion rod and the through hole II of the inner sleeve with a special wire to complete the assembly of the mold; Step 3. Install the mold on a reheating simulator to heat the mold and the blank. Select the method of passing electric current to use Joule heat to heat the mold and the blank to a specified temperature at a specified heating rate. After reaching the forming temperature, keep the temperature for a specified time. Step 4. The force-applying mechanism of the thermal simulator presses on the extrusion rod, and transmits the pressure to the extrusion gasket through the extrusion needle. The extrusion gasket presses the blank downward toward the guide die and transmits it to the concave die, so that the concave die tends to move downward; Step 5. The die is supported by the ejector pin. When the blank transmits force to the guide die and the die, the die is supported by the ejector pin and cannot move. At this time, the blank is subjected to pressure and begins to undergo plastic deformation after reaching a certain value. It enters the die through the guide die and fills the cavity of the die, forming a part that is consistent with the shape and size of the die cavity. Step 6. After cooling, remove the extrusion needle and rotate the ejector pin out of the inner sleeve, take out the formed part, and complete the entire forming process.

2. The hot extrusion die device for forming micro gears according to claim 1, characterized in that: One end of the extrusion rod is a flange, and the flange of the extrusion rod is provided with a through hole I. One end of the inner sleeve is also provided with a flange, and the flange of the inner sleeve is provided with a through hole II.

3. The hot extrusion die device for forming micro gears according to claim 2, characterized in that: During the extrusion process, the through hole I on the flange at the end of the extrusion rod is connected with the through hole II on the flange at the upper end of the inner sleeve using a special wire.

4. The hot extrusion die device for forming micro gears according to claim 1, characterized in that: The extrusion needle is in the shape of a stepped shaft, and the small shaft end portion of the extrusion needle is placed in the through hole III of the inner sleeve.

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