A conical part forming method based on forced lubrication

Abstract

This invention provides a method for forming conical parts based on forced lubrication. The blank is placed in the conical cavity of an inner die. At this time, the inner die is suspended on the liquid surface under the action of a spring, and the liquid pressure in the main hydraulic chamber, auxiliary hydraulic chamber, and hydraulic channel is low. The punch is controlled to move downwards, rapidly increasing the liquid pressure in the main hydraulic chamber, auxiliary hydraulic chamber, and hydraulic channel to a high-pressure range, and then maintaining this pressure constant. After forming, the pressure is released and the workpiece is removed. The thin-walled conical part produced using this method has good uniformity and consistency on its outer surface, without any missing material defects.

Description

Technical Field

[0001] This invention relates to the field of thin-walled conical part manufacturing technology, and specifically to a method for forming conical parts based on forced lubrication. Background Technology

[0002] Conical precision parts with concave inner sections are core functional components of certain special devices. Cold extrusion can increase the density and refine the grain size of these parts, and allow for unmachined inner and outer surfaces. However, direct extrusion often results in the workpiece sticking to the die during the forming process. When the workpiece is removed by external force, a 0.1–0.3 mm defect appears on the outer surface. Therefore, direct extrusion is not commonly used to manufacture these precision parts in existing methods. Furthermore, these parts require forming force fluctuations to be within 5%, a requirement that is difficult to achieve using existing cold extrusion equipment.

[0003] In addition, the uniformity of the cone tip structure of this type of precision conical part is also a crucial factor affecting its performance. Conventional extrusion equipment usually produces a large allowance at the cone tip, with an allowance length of about 5mm, which requires secondary precision machining to meet the usage requirements. Summary of the Invention

[0004] In order to solve at least the technical problems mentioned in the background art, the present invention aims to provide a method for forming conical parts based on forced lubrication.

[0005] The present invention adopts the following technical solutions.

[0006] A method for forming tapered parts based on forced lubrication employs a die forming device.

[0007] The die forming device includes an outer die, an inner die that can slide up and down is fitted inside the cavity of the outer die, a main hydraulic chamber is located below the inner die, and a punch is provided above the inner die.

[0008] A tapered cavity is provided on the inner die, a secondary hydraulic chamber is provided on the inner die and below the tapered cavity, and a hydraulic adjustment mechanism is provided on the side wall of the outer die.

[0009] A push rod assembly is installed in the main hydraulic chamber. A spring is sleeved on the push rod assembly. The lower end of the spring abuts against the bottom wall of the main hydraulic chamber, and the upper end of the spring abuts against the bottom wall of the inner die. The upper end of the push rod of the push rod assembly extends into the secondary hydraulic chamber. A hydraulic channel is provided on the push rod assembly, which communicates with the secondary hydraulic chamber and the main hydraulic chamber.

[0010] The steps of the tapered part forming method include:

[0011] Step 1: Place the blank in the conical cavity of the inner die. At this time, the inner die is suspended on the liquid surface under the action of the spring. The liquid pressure in the main hydraulic chamber, the auxiliary hydraulic chamber, and the hydraulic channel is low pressure.

[0012] Step 2: Control the downward movement of the punch to rapidly increase the liquid pressure in the main hydraulic chamber, auxiliary hydraulic chamber, and hydraulic channel to the ultra-high pressure range, and maintain it at a constant level;

[0013] Step 3: After forming is complete, release the pressure and remove the workpiece.

[0014] As a preferred embodiment, the low pressure is a pressure not exceeding 1 MPa, and the ultra-high pressure is a pressure of 300–600 MPa.

[0015] As a preferred option, in step 2, when the punch moves downward, the liquid pressure rapidly increases from 0.2MPa to 0.5MPa to ultra-high pressure.

[0016] As a preferred embodiment, the hydraulic adjustment mechanism includes a short pipe, the inner cavity of which serves as a pressure control channel and is connected to the main hydraulic chamber. A pressure regulating slider is provided on the short pipe, and the outer end of the short pipe is connected to a low-pressure chamber, wherein the liquid pressure in the low-pressure chamber is 0-32 MPa.

[0017] As a preferred option, the pressure increase ratio of the pressure regulating slider is 1:5 to 1:20.

[0018] As a preferred option, the wall thickness of the tapered part is 1 to 3 mm.

[0019] As a preferred option, the tapered component is made of tantalum or copper.

[0020] To prevent excess material from forming at the tip of the tapered component, an arc-shaped plate is provided at the top of the auxiliary hydraulic chamber. The arc-shaped plate is fixedly connected to the inner die. The arc-shaped plate has several micro-holes with a diameter of no more than 1 mm. The arc-shaped concave part of the arc-shaped plate matches the arc surface of the tip of the tapered component.

[0021] Beneficial effects: The thin-walled conical part made using the method of the present invention has good uniformity and consistency on its outer surface, with no missing material defects, and fundamentally avoids the generation of excess material at the tip of the cone. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the tapered part forming process based on forced lubrication in Example 1. Figure 1 The liquid pressure in each chamber and hydraulic passage is low.

[0023] Figure 2 This is a schematic diagram of the tapered part forming process based on forced lubrication in Example 1. Figure 2 During the downward movement of the punch;

[0024] Figure 3 This is a schematic diagram of the tapered part forming process based on forced lubrication in Example 1. Figure 2 The downward movement of the punch has ended;

[0025] Figure 4 This is a schematic diagram of the location of the arc-shaped plate in Example 3;

[0026] Figure 5 for Figure 4 Enlarged view of part A in the middle. Detailed Implementation

[0027] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] Example 1

[0029] Combination Figures 1 to 3 As shown, one type of die forming device will be described first. It includes an outer die 2, and an inner die 3 that can slide up and down is fitted inside the inner cavity of the outer die 2. The mating part between the inner die 3 and the outer die 2 is in a sliding seal. The inner die 3 has a main hydraulic chamber 8 below it, and a punch 1 is provided above it. A tapered cavity is provided on the inner die 3, and a secondary hydraulic chamber 7 is provided on the inner die 3 and below the tapered cavity. A hydraulic adjustment mechanism is provided on the side wall of the outer die 2. A push rod assembly 6 is provided in the main hydraulic chamber 8. A spring 5 is sleeved on the push rod assembly 6. The lower end of the spring 5 abuts against the bottom wall of the main hydraulic chamber 8, and the upper end of the spring 5 abuts against the bottom wall of the inner die 3. The upper end of the push rod of the push rod assembly 6 extends into the secondary hydraulic chamber 7. A hydraulic channel 9 is provided on the push rod assembly 6, and the hydraulic channel 9 communicates with the secondary hydraulic chamber 7 and the main hydraulic chamber 8. The hydraulic adjustment mechanism includes a short pipe 11, which is installed on the outer die 2. The inner cavity of the short pipe 11 serves as a pressure control channel 10 and is connected to the main hydraulic chamber 8. A pressure regulating slider 13 is provided on the short pipe, and the outer end of the short pipe is connected to a low-pressure chamber 12. The liquid pressure in the low-pressure chamber 12 is 0 to 32 MPa. The pressure increase ratio of the pressure regulating slider 13 is 1:5 to 1:20.

[0030] Example 2

[0031] A method for forming a conical part based on forced lubrication, using the die forming apparatus described in Example 1 to prepare a pure copper conical part (molded cover) with a wall thickness of 1.5 mm, includes the following steps:

[0032] Step 1: Place the blank in the conical cavity of the inner die 3. At this time, the inner die 3 is suspended on the liquid surface under the action of the spring 5, and its state is as follows. Figure 1 As shown, the liquid pressure in the main hydraulic chamber 8, the auxiliary hydraulic chamber 7, and the hydraulic passage 9 is a low pressure not exceeding 1 MPa;

[0033] Step 2: Control the punch 1 to move downward at a uniform speed (downward speed is 10mm / s) so that the liquid pressure in the main hydraulic chamber 8, the auxiliary hydraulic chamber 7, and the hydraulic channel 9 can be rapidly brought to the ultra-high pressure range and kept constant.

[0034] The maximum unit pressure between the pure copper conical part and the inner die 3 is 200MPa. Therefore, the pressure of the low-pressure chamber 12 is adjusted to 20MPa, and the pressure increase ratio of the slider is adjusted to 1:10. When the pressure in the main hydraulic chamber 8 reaches 200MPa, a wetting layer will be formed between the pure copper conical part and the inner die 3, thereby achieving forced lubrication. The unit pressure fluctuates between 197MPa and 200MPa, and the pressure fluctuation is less than 3%.

[0035] Step 3, after the forming is completed (e.g.) Figure 3 (As shown), depressurize and remove workpiece 4.

[0036] Example 3

[0037] In this embodiment, the die forming device is as follows: Figure 4 and Figure 5As shown, the device includes an outer die 2, an inner die 3 that can slide up and down within the inner cavity of the outer die 2, and the mating parts of the inner die 3 and the outer die 2 are in a sliding seal. The inner die 3 has a main hydraulic chamber 8 below it, and a punch 1 is positioned above it. A tapered cavity is provided on the inner die 3, and a secondary hydraulic chamber 7 is provided on the inner die 3 and below the tapered cavity. A hydraulic adjustment mechanism is provided on the side wall of the outer die 2. A push rod assembly 6 is provided within the main hydraulic chamber 8, and a spring 5 is sleeved on the push rod assembly 6. The lower end of the spring 5 abuts against the bottom wall of the main hydraulic chamber 8, and the upper end of the spring 5 abuts against the bottom wall of the inner die 3. The upper end of the push rod of the push rod assembly 6 extends into the secondary hydraulic chamber 7. A hydraulic channel 9 is provided on the push rod assembly 6, and the hydraulic channel 9 communicates with the secondary hydraulic chamber 7 and the main hydraulic chamber 8. The hydraulic adjustment mechanism includes a short pipe 11, which is mounted on the outer die 2. The inner cavity of the short pipe 11 serves as a pressure control channel 10, communicating with the main hydraulic chamber 8. A pressure regulating slider 13 is installed on the short pipe, and its outer end is connected to a low-pressure chamber 12. The liquid pressure in the low-pressure chamber 12 is 0–32 MPa. The pressure increase ratio of the pressure regulating slider 13 is 1:5–1:20. An arc-shaped plate 14 is installed at the top of the auxiliary hydraulic chamber 7, and is fixedly connected to the inner die 3. The arc-shaped plate 14 has several micro-holes 15 with a diameter not exceeding 1 mm. The arc-shaped concave part of the arc-shaped plate 14 matches the arc surface of the cone tip of the conical part. During use, the high-pressure liquid in the auxiliary hydraulic chamber 7 enters the cavity of the inner die 3 through the micro-holes 15, but the blank does not enter the micro-holes 15.

[0038] A method for forming a conical part based on forced lubrication, using the die forming apparatus in this embodiment to prepare a pure tantalum conical part (molded cover) with a wall thickness of 1 mm, includes the following steps:

[0039] Step 1: Place the blank in the conical cavity of the inner die 3. At this time, the inner die 3 is suspended on the liquid surface under the action of the spring 5. The liquid pressure in the main hydraulic chamber 8, the auxiliary hydraulic chamber 7, and the hydraulic channel 9 is a low pressure of no more than 1 MPa.

[0040] Step 2: Control the punch 1 to move downward at a uniform speed (downward speed is 9mm / s) so that the liquid pressure in the main hydraulic chamber 8, the auxiliary hydraulic chamber 7, and the hydraulic channel 9 can be rapidly brought to the ultra-high pressure range and kept constant.

[0041] The maximum unit pressure between the pure tantalum conical part and the inner die 3 is 600MPa. Therefore, the pressure of the low-pressure chamber 12 is adjusted to 30MPa, and the pressure increase ratio of the slider is adjusted to 1:20. When the pressure in the main hydraulic chamber 8 reaches 600MPa, a wetting layer will be formed between the pure tantalum conical part and the inner die 3, thereby achieving forced lubrication. The unit pressure fluctuates between 592MPa and 500MPa, and the pressure fluctuation is less than 3%.

[0042] Step 3: After forming is complete, release the pressure and remove the workpiece 4.

[0043] In this invention, when the punch 1 descends to extrude the blank, the inner die 3 moves downward. At this time, the liquid in the main hydraulic chamber 8, the auxiliary hydraulic chamber 7, and the hydraulic channel 9 is compressed, and its hydraulic pressure rapidly rises from low pressure (0MPa~1MPa) to ultra-high pressure (maximum pressure 600MPa). When the pressure ratio between the ultra-high pressure liquid in these oil chambers and the low pressure liquid in the low pressure chamber 12 exceeds a certain set value, the adjusting slider moves outward to ensure that the excess pressure in the oil chamber is within a constant range. On the other hand, the liquid in the auxiliary hydraulic chamber 7 enters the cavity through the micro-holes on the arc plate 14 and forms an ultra-high pressure liquid lubricating film on the inner wall of the cavity. The arc plate 14 and the ultra-high pressure liquid lubricating film work together to prevent excess material and flash from forming at the cone tip.

[0044] The samples obtained in Examples 2 and 3 were tested. The entire inner and outer surfaces of the obtained conical parts were free of pits or missing material. In particular, the cone tip of the cone obtained in Example 3 had no excess material and no flash. The outer diameter deviation of the center part of the cone in Example 2 was -0.015 to +0.021 mm in the same radial section, and the inner diameter deviation of the center part of the cone in Example 2 was -0.01 to +0.012 mm in the same radial section. The outer diameter deviation of the center part of the cone in Example 3 was -0.027 to +0.035 mm in the same radial section, and the inner diameter deviation of the center part of the cone in Example 3 was -0.02 to +0.032 mm in the same radial section.

Claims

1. A method for forming a conical part based on forced lubrication, employing a die forming device, characterized in that: The die forming device includes an outer die (2), an inner die (3) that can slide up and down is fitted in the inner cavity of the outer die (2), a main hydraulic chamber (8) is provided below the inner die (3), and a punch (1) is provided above the inner die (3). A tapered cavity is provided on the inner die (3), and a secondary hydraulic chamber (7) is provided on the inner die (3) and below the tapered cavity. A hydraulic adjustment mechanism is provided on the side wall of the outer die (2). A push rod assembly (6) is provided in the main hydraulic chamber (8). A spring (5) is sleeved on the push rod assembly (6). The lower end of the spring (5) abuts against the bottom wall of the main hydraulic chamber (8), and the upper end of the spring (5) abuts against the bottom wall of the inner die (3). The upper end of the push rod of the push rod assembly (6) extends into the secondary hydraulic chamber (7). A hydraulic channel (9) is provided on the push rod assembly (6). The hydraulic channel (9) communicates with the secondary hydraulic chamber (7) and the main hydraulic chamber (8). The steps of the tapered part forming method include: Step 1: Place the blank in the conical cavity of the inner die (3). At this time, the inner die (3) is suspended on the liquid surface under the action of the spring (5). The liquid pressure in the main hydraulic chamber (8), the auxiliary hydraulic chamber (7), and the hydraulic channel (9) is low. Step 2: Control the punch (1) to move down, so that the liquid pressure in the main hydraulic chamber (8), the auxiliary hydraulic chamber (7), and the hydraulic channel (9) rises rapidly to the ultra-high pressure range and remains constant; Step 3: After the forming is completed, release the pressure and remove the workpiece (4).

2. The method for forming a conical part according to claim 1, characterized in that: The low pressure is no more than 1 MPa, and the ultra-high pressure is 300~600 MPa.

3. The method for forming a conical part according to claim 1, characterized in that: In step 2, when the punch (1) moves down, the liquid pressure rapidly rises from 0.2MPa~0.5MPa to ultra-high pressure.

4. The method for forming a conical part according to claim 1, characterized in that: The hydraulic adjustment mechanism includes a short pipe, the inner cavity of which serves as a pressure control channel (10) and is connected to the main hydraulic chamber (8). A pressure regulating slider (13) is provided on the short pipe, and the outer end of the short pipe is connected to a low-pressure chamber (12). The liquid pressure in the low-pressure chamber (12) is 0~32Mpa.

5. The method for forming a tapered part according to claim 4, characterized in that: The pressure increase ratio of the pressure regulating slider (13) is 1:5~1:

20.

6. The method for forming a tapered part according to claim 5, characterized in that: The wall thickness of the tapered part is 1~3mm.

7. The method for forming a tapered part according to claim 5, characterized in that: The tapered part is made of tantalum or copper.

8. The method for forming a tapered part according to claim 7, characterized in that: The top of the auxiliary hydraulic chamber (7) is provided with an arc plate (14), which is fixedly connected to the inner mold (3). The arc plate (14) is provided with a number of micro holes (15) with a diameter of no more than 1 mm. The arc concave part of the arc plate (14) matches the arc surface of the cone tip of the cone.

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