Powder metallurgy gear manufacturing mold and manufacturing method

Abstract

The application discloses a powder metallurgy gear manufacturing mold, which comprises a straight-tooth machining mold and a drum-shaped tooth shaping mold; the straight-tooth machining mold comprises a straight-tooth upper punch, a straight-tooth middle mold, a straight-tooth lower punch and a straight-tooth core rod; the straight-tooth upper punch is located at the top, the straight-tooth lower punch is located at the bottom, the lower end of the straight-tooth upper punch and the upper end of the straight-tooth lower punch are correspondingly embedded in the middle mold, the lower end of the straight-tooth upper punch, the upper end of the straight-tooth lower punch and the middle mold form a straight-tooth mold cavity, and the straight-tooth core rod extends into the straight-tooth mold cavity from the straight-tooth lower punch and extends upwards into the straight-tooth upper punch. The drum-shaped gear is manufactured by using the powder metallurgy process, the material utilization rate can be effectively improved to more than 95%, and the resources can be effectively saved and the cost can be reduced; the powder metallurgy gear is formed by using the mold, under normal use conditions, one mold can press tens of thousands to hundreds of thousands of gears, continuous production can be realized, the production efficiency is high, and the production cost is greatly reduced.

Description

Technical Field

[0001] This invention relates to a method for manufacturing powder metallurgy products, specifically a mold and method for manufacturing powder metallurgy drum-shaped gears. Background Technology

[0002] In the existing technology, the processing method of powder metallurgy drum gears is usually mechanical processing, and the common production process of drum gears is: blanking → rough machining → heat treatment → fine machining of the shape → pre-hogging → fine hogging of drum gears.

[0003] For example, the technical solution disclosed in Publication (Announcement) No. CN105612018B is "a gear processing machine", which uses the cooperation of various cutting tools and mechanical equipment to realize the processing of drum-shaped teeth.

[0004] The main disadvantages of this type of machining are as follows:

[0005] 1) The process is complex, the production cycle is long, and the production cost is high;

[0006] 2) During precision machining / precision gear hobbing, multiple tests are required, and the equipment and processing parameters need to be adjusted based on the data, resulting in a long setup time;

[0007] 3) Tool wear during machining affects tooth profile accuracy and results in poor product consistency;

[0008] 4) Mass production is difficult to achieve.

[0009] Therefore, in order to solve the above problems, it is necessary to develop a powder metallurgy drum gear manufacturing mold and manufacturing method that can improve product quality. Summary of the Invention

[0010] The purpose of this invention is to address the shortcomings of existing technologies by providing a powder metallurgy drum-shaped gear manufacturing mold and manufacturing method; the technical solution is as follows:

[0011] A powder metallurgy drum-shaped gear manufacturing mold includes a spur gear machining mold and a drum-shaped gear forming mold. The spur gear machining mold includes a spur gear upper punch, a spur gear middle mold, a spur gear lower punch, and a spur gear mandrel. The spur gear upper punch is located at the top, and the spur gear lower punch is located at the bottom. The lower end of the spur gear upper punch and the upper end of the spur gear lower punch are respectively embedded in the middle mold. The lower end of the spur gear upper punch, the upper end of the spur gear lower punch, and the middle mold constitute a spur gear mold cavity. The spur gear mandrel passes through the spur gear lower punch from below and extends into the spur gear mold cavity, and extends upward into the spur gear upper punch.

[0012] The drum-shaped tooth forming mold includes a drum-shaped tooth upper punch, a drum-shaped tooth middle mold, a drum-shaped tooth lower punch, and a drum-shaped tooth core rod. The drum-shaped tooth upper punch is located at the top, and the drum-shaped tooth lower punch is located at the bottom. The lower end of the drum-shaped tooth upper punch and the upper end of the drum-shaped tooth lower punch are respectively embedded in the middle mold. The lower end of the drum-shaped tooth upper punch, the upper end of the drum-shaped tooth lower punch, and the middle mold constitute the drum-shaped tooth mold cavity. The drum-shaped tooth core rod passes through the drum-shaped tooth lower punch from below and extends into the drum-shaped tooth mold cavity, and extends upward into the drum-shaped tooth upper punch.

[0013] Furthermore, the final height of the drum-shaped tooth is set to 4mm, the maximum outer diameter is set to 8.95-9.05mm, and the inner diameter specification is set to φ4.9.

[0014] Furthermore, the maximum bulging amount of the final bulging tooth is set to 0.134 mm, the profile at the tooth rib is required to be less than 0.035 mm, and the profile at the tooth tip is required to be less than 0.06 mm.

[0015] This invention also provides a method for manufacturing powder metallurgy drum-shaped gears, comprising the following steps:

[0016] 1) Forming: Using a spur gear machining die, powder metallurgy iron powder is placed into the spur gear mold cavity, and powder metallurgy spur gears are obtained by using a press and a spur gear machining die.

[0017] 2) Sintering: The obtained powder metallurgy spur gear is sintered in a sintering furnace to obtain a metal spur gear;

[0018] 3) Co-folding: Removing burrs from metal spur gears using a co-folding machine;

[0019] 4) Oil immersion: The deburred metal spur gears are immersed in oil for rust prevention;

[0020] 5) Shaping: The oil-immersed anti-corrosion metal spur gear obtained in step 4 is placed into the drum-shaped tooth mold cavity of the drum-shaped shaping mold, and the drum-shaped outline is pressed out by the drum-shaped tooth shaping mold to finally obtain the powder metallurgy drum-shaped gear.

[0021] 6) Place the powder metallurgy drum gear into an ultrasonic cleaner for cleaning and inspect the packaging.

[0022] Furthermore, the sintering temperature in step 2 is set to 1120±10℃.

[0023] Further, step 5 specifically involves placing the product obtained in step 4 into the drum-shaped tooth mold cavity, where the tooth profile of the drum-shaped tooth core and the drum-shaped tooth mold plays a positioning role for the product.

[0024] The outer rod and the upper punch of the drum-shaped teeth are pressed down simultaneously by the press. The press controls the downward stroke to ensure that there is a 0.1mm gap between the outer rod and the middle die of the drum-shaped teeth. The upper and lower end faces of the product are squeezed, and the toothed sides at both ends are controlled by the die and are subjected to inward pressure. As the product height decreases in the middle part, the material expands in the diameter direction until it is tightly attached to the inner wall of the middle die and the outer rod of the drum-shaped teeth. Finally, the shape of the product is consistent with the drum shape of the die.

[0025] Furthermore, the press is a 15T shaping machine with a total shaping amount of 0.05-0.10mm.

[0026] Beneficial effects: The present invention has the following beneficial effects:

[0027] 1) This invention requires the use of powder metallurgy to manufacture drum-shaped gears, which can effectively improve material utilization to over 95%, effectively saving resources and reducing costs;

[0028] 2) The powder metallurgy gears of the present invention are formed by pressing with a mold. Under normal use conditions, a set of molds can press tens of thousands to hundreds of thousands of gears, which can realize continuous production, high production efficiency, and greatly reduce production costs.

[0029] 3) The technical solution of the present invention is to first process spur gears by using a spur gear machining mold, and then, after a series of processes, to process the spur gears by using a drum-shaped gear forming mold to finally obtain drum-shaped teeth of metal powder material. After the powder metallurgy gears are shaped by the mold, the surface roughness of the contact surface with the mold wall is excellent, the product dimensional accuracy is high, and the consistency is better.

[0030] 4) The mold structure design of the present invention is reasonable. Both the straight tooth processing mold and the drum tooth forming mold are designed according to the mold standard, and the manufacturing, processing and assembly are very convenient and quick. Attached Figure Description

[0031] Figure 1 This is a structural diagram of the straight gear machining mold of the present invention;

[0032] Figure 2 This is a structural diagram of the drum-shaped tooth forming mold of the present invention;

[0033] Figure 3 This is a diagram of the drum-shaped tooth structure of the present invention;

[0034] Figure 4 This is a structural diagram of the tooth rib of the drum-shaped tooth of the present invention. Detailed Implementation

[0035] The present invention will be further illustrated below with reference to the accompanying drawings and specific embodiments. These embodiments are implemented based on the technical solutions of the present invention, and it should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention.

[0036] A powder metallurgy drum-shaped gear manufacturing mold includes a spur gear machining mold and a drum-shaped gear shaping mold.

[0037] like Figure 1 As shown, the spur gear machining mold includes a spur gear upper punch 101, a spur gear middle mold 102, a spur gear lower punch 103, and a spur gear mandrel 104. The spur gear upper punch 101 is located at the top, and the spur gear lower punch 103 is located at the bottom. The lower end of the spur gear upper punch 101 and the upper end of the spur gear lower punch 103 are respectively embedded in the middle mold. The lower end of the spur gear upper punch 101, the upper end of the spur gear lower punch 103, and the middle mold constitute the spur gear mold cavity. The spur gear mandrel 104 passes through the spur gear lower punch 103 from below and extends into the spur gear mold cavity, and extends upward into the spur gear upper punch 101.

[0038] like Figure 2 As shown, the drum-shaped tooth forming mold includes a drum-shaped tooth upper punch 201, a drum-shaped tooth middle mold 202, a drum-shaped tooth lower punch 203, and a drum-shaped tooth mandrel 204. The drum-shaped tooth upper punch 201 is located at the top, and the drum-shaped tooth lower punch 203 is located at the bottom. The lower end of the drum-shaped tooth upper punch 201 and the upper end of the drum-shaped tooth lower punch 203 are respectively embedded in the middle mold. The lower end of the drum-shaped tooth upper punch 201, the upper end of the drum-shaped tooth lower punch 203, and the middle mold constitute the drum-shaped tooth mold cavity. The drum-shaped tooth mandrel 204 passes through the drum-shaped tooth lower punch 203 from below and extends into the drum-shaped tooth mold cavity, and extends upward into the drum-shaped tooth upper punch 201.

[0039] like Figure 3 As shown, the final height of the drum-shaped tooth is set to 4mm, the maximum outer diameter is set to 8.95-9.05mm, and the inner diameter specification is set to φ4.9.

[0040] like Figure 4 As shown, the maximum bulging amount of the final bulging tooth is set to 0.134 mm, the profile at the tooth rib is required to be less than 0.035 mm, and the profile at the tooth tip is required to be less than 0.06 mm.

[0041] This invention also utilizes a spur gear machining mold and a drum-shaped gear forming mold to manufacture powder metallurgy drum-shaped gears, as detailed below:

[0042] First, the forming process: using a spur gear machining mold, powder metallurgy iron powder is placed into the spur gear mold cavity, and powder metallurgy spur gears are obtained by using a press and the spur gear machining mold.

[0043] Then, sintering: The obtained powder metallurgy spur gear is sintered in a sintering furnace to obtain a metal spur gear; and the sintering temperature is set to 1120±10℃.

[0044] Co-folding: Removing burrs from metal spur gears using a co-folding machine; Oil immersion: Immersing the deburred metal spur gears in oil for rust prevention;

[0045] Then, the oil-immersed anti-corrosion metal spur gear is placed into the drum-shaped tooth mold cavity of the drum-shaped forming mold, and the drum-shaped outline is pressed out by the drum-shaped tooth forming mold, finally obtaining the powder metallurgy drum-shaped gear.

[0046] The tooth profiles of the drum-shaped toothed mandrel 204 and the drum-shaped toothed middle mold 202 serve to position the product. The drum-shaped toothed outer rod and the drum-shaped toothed upper punch 201 are pressed down simultaneously by the press. The press controls the pressing stroke to ensure a 0.1mm gap between the drum-shaped toothed outer rod and the drum-shaped toothed middle mold 202. The upper and lower end faces of the product are compressed, and the toothed sides at both ends are controlled by the mold and subjected to inward pressure. Due to the reduced product height, the material in the middle expands in the diameter direction until it tightly adheres to the inner wall of the drum-shaped toothed middle mold 202 and the drum-shaped toothed outer rod. The final product shape matches the drum shape of the mold. The press is a 15T forming machine with a total forming amount of 0.05-0.10mm.

[0047] The production process of the powder metallurgy drum gear of the present invention mainly involves pressing powder into a rigid spur gear processing mold using a forming press to form a spur gear; sintering in a sintering furnace at a certain temperature and time under a protective atmosphere, metallurgically connecting the particles to form a porous metal spur gear; placing the sintered metal spur gear into the middle mold of the drum gear forming mold, and shaping it using a forming machine and mold; after being squeezed from top to bottom, the outer wall of the gear expands to fit tightly against the spherical middle mold, finally obtaining a drum gear with a smooth outer wall and high dimensional accuracy.

[0048] The invention utilizes powder metallurgy to manufacture drum-shaped gears, which can effectively improve material utilization to over 95%, effectively saving resources and reducing costs. The powder metallurgy gears of this invention are formed by mold pressing. Under normal use conditions, one mold can press tens of thousands to hundreds of thousands of gears, enabling continuous production, high production efficiency, and significantly reducing production costs.

[0049] The technical solution of this invention is to first process spur gears using a spur gear machining mold, and then, after a series of processes, to shape the spur gears using a drum-shaped gear shaping mold, ultimately obtaining drum-shaped teeth of metal powder material. After the powder metallurgy gears are shaped using the mold, the surface roughness of the contact surface with the mold wall is excellent, the product dimensional accuracy is high, and the consistency is better.

[0050] The mold structure of this invention is reasonably designed. Both the straight tooth machining mold and the drum-shaped tooth forming mold are designed according to mold standards, making the manufacturing, processing and assembly very convenient and quick.

[0051] The above-described specific embodiments are merely preferred embodiments of the present invention and are not intended to limit the implementation of the present invention or the scope of the claims. All equivalent changes and modifications made in accordance with the scope of patent protection of the present invention should be included within the scope of the present invention patent application.

Claims

1. A method for manufacturing a powder metallurgy drum-shaped gear, characterized in that: This manufacturing method utilizes straight-tooth machining molds and drum-shaped tooth shaping molds. The spur gear machining mold includes a spur gear upper punch (101), a spur gear middle mold (102), a spur gear lower punch (103), and a spur gear mandrel (104). The spur gear upper punch (101) is located above, and the spur gear lower punch (103) is located below. The lower end of the spur gear upper punch (101) and the upper end of the spur gear lower punch (103) are respectively embedded in the middle mold. The lower end of the spur gear upper punch (101), the upper end of the spur gear lower punch (103), and the middle mold constitute a spur gear mold cavity. The spur gear mandrel (104) passes through the spur gear lower punch (103) from below and extends into the spur gear mold cavity, and extends upward into the spur gear upper punch (101). The drum-shaped tooth forming mold includes a drum-shaped tooth upper punch (201), a drum-shaped tooth middle mold (202), a drum-shaped tooth lower punch (203), and a drum-shaped tooth core rod (204). The drum-shaped tooth upper punch (201) is located at the top, and the drum-shaped tooth lower punch (203) is located at the bottom. The lower end of the drum-shaped tooth upper punch (201) and the upper end of the drum-shaped tooth lower punch (203) are respectively embedded in the middle mold. The lower end of the drum-shaped tooth upper punch (201), the upper end of the drum-shaped tooth lower punch (203), and the middle mold constitute the drum-shaped tooth mold cavity. The drum-shaped tooth core rod (204) passes through the drum-shaped tooth lower punch (203) from below and extends into the drum-shaped tooth mold cavity, and extends upward into the drum-shaped tooth upper punch (201). The production method includes the following steps: 1) Forming: Using a spur gear machining die, powder metallurgy iron powder is placed into the spur gear mold cavity, and powder metallurgy spur gears are obtained by using a press and a spur gear machining die. 2) Sintering: The obtained powder metallurgy spur gear is sintered in a sintering furnace to obtain a metal spur gear; the sintering temperature is set to 1120±10℃; 3) Co-folding: Removing burrs from metal spur gears using a co-folding machine; 4) Oil immersion: The deburred metal spur gears are immersed in oil for rust prevention; 5) Shaping: Place the product obtained in step 4) into the drum-shaped tooth mold cavity. The tooth profile of the drum-shaped tooth core rod (204) and the drum-shaped tooth middle mold (202) plays a positioning role for the product. The outer rod of the drum-shaped teeth and the upper punch of the drum-shaped teeth (201) are pressed down simultaneously under the action of the press. The press controls the pressing stroke to ensure that there is a 0.1mm gap between the outer rod of the drum-shaped teeth and the middle mold of the drum-shaped teeth (202). The upper and lower end faces of the product are squeezed, and the tooth sides at both ends are controlled by the mold and are subjected to inward pressure. As the height of the product decreases, the material in the middle part expands in the diameter direction until it is tightly attached to the inner wall of the middle mold of the drum-shaped teeth (202) and the outer rod of the drum-shaped teeth. Finally, the shape of the product is consistent with the drum shape of the mold. 6) Place the powder metallurgy drum gear into an ultrasonic cleaner for cleaning and inspect the packaging.

2. The method for manufacturing a powder metallurgy drum-shaped gear according to claim 1, characterized in that: The final height of the drum-shaped teeth was set to 4mm, the maximum outer diameter to 8.95-9.05mm, and the inner diameter to 4.9mm.

3. The method for manufacturing a powder metallurgy drum-shaped gear according to claim 1, characterized in that: The maximum bulging amount of the final bulging tooth is set to 0.134 mm, the profile at the tooth rib is required to be less than 0.035 mm, and the profile at the tooth tip is required to be less than 0.06 mm.

4. The method for manufacturing a powder metallurgy drum-shaped gear according to claim 1, characterized in that: The press is a 15T forming machine with a total forming amount of 0.05-0.10mm.

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