Forming device and process of large module gears by semi-solid rolling using low-frequency vibration forming method

Abstract

A forming device and process for semi-solid rolling of large-module gears using a low-frequency vibration Fan Cheng method, comprising a workbench, a supporting device connected to the workbench, a blank mounted on the supporting device, a rolling device symmetrically arranged on the outside of the blank, a radial feed hydraulic cylinder assembly connected horizontally to the outside of the rolling device, an axial feed hydraulic cylinder assembly connected vertically to the outside of the rolling device, and a servo motor connected to the axial feed hydraulic cylinder assembly; low-frequency vibration is used to assist in reducing the resistance to plastic deformation, and a double rolling die with no cutting edge hob on the surface is used, similar to the principle of hobbing gears using the Fan Cheng method, to perform symmetrical progressive rolling forming on the semi-solid large-module gear profile, which can form large-module gear profiles with small forming load and high forming efficiency. The formed part has continuous tissue fibers, high tooth profile accuracy, and high part reliability.

Description

Technical Field

[0001] The present invention belongs to the technical field of large-module gear forming and processing, and in particular relates to a forming device and process for large-module gears using a semi-solid rolling method using a low-frequency vibration forming method. Background Art

[0002] Large-module gears are widely used in heavy-duty equipment due to their strong load-bearing capacity. The main methods of forming gears are cutting and plastic forming. Currently, most gear manufacturers mainly use cutting as their production method. Cutting is mainly divided into gear shaping, gear milling, and gear hobbing. The above-mentioned cutting methods have many disadvantages. Cutting will cut the fiber structure of the material, which will reduce the performance of the parts. It also has low material utilization, high production costs, and low manufacturing efficiency. The production methods of gear plastic forming currently mainly include multi-die rolling, extrusion and other processes. The die arrangement of the multi-die rolling process is generally parallel to the die axis and the blank axis. When forming toothed parts with different numbers of teeth, the die adjustment is inconvenient, and due to the limitation of the die space position, the diameter of the formed gear is generally small. At the same time, the multi-tooth rolling process mainly processes toothed parts with smaller modules. It is not suitable for processing large-module gears due to the excessive forming force.

[0003] The integral extrusion process, however, requires high extrusion pressure and high equipment requirements, making it unsuitable for forming large-module gears. Rolling gear tooth profiles are usually performed at room temperature, so only small-module gears can be formed.

[0004] One method for plastic forming gear rolling (Method for the cold form generating of cylindrical workpieces [P], U.S. Patent No. 3032871) is to use the principle of the fan forming method in cutting processing, that is, the mold structure is in the shape of a worm, the mold axis and the blank axis are arranged in different planes, and the tooth-shaped parts are rolled by the fan forming motion of the two. At present, this gear rolling plastic forming process at room temperature has the following shortcomings: (1) Directly rolling the blank along the circumferential direction of the rolling die at room temperature causes large forming force, severe mold wear, high energy consumption, and high requirements for forming equipment, which is not suitable for rolling forming of large module gears; (2) The fluidity of the cold rolled gear blank material is poor, and the filling performance of the tooth shape of large module gears is poor, resulting in the problem of tooth shape shortage; (3) Due to the large friction and poor plasticity of single-pass rolling forming, the tooth shape of large module gears will not be fully filled, the forming accuracy is poor, and the tooth shape quality is difficult to guarantee. Summary of the Invention

[0005] In order to overcome the shortcomings of the above-mentioned technology, the purpose of the present invention is to provide a forming device and process for semi-solid rolling of large module gears by low-frequency vibration Fan Cheng method, which adopts low-frequency vibration to assist in reducing the resistance to plastic deformation, and uses a principle similar to Fan Cheng method of hob cutting gears. A double rolling die with no cutting edge hob on the surface is used to perform symmetrical progressive rolling forming on the semi-solid large module gear profile, which can form large module gear profiles with small forming load and high forming efficiency. The formed parts have continuous tissue fibers, high tooth profile accuracy and high part reliability.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A forming device for semi-solid rolling of large-module gears using a low-frequency vibration forming method includes a workbench 1, a supporting device 3 is connected to the workbench 1, a blank 2 is mounted on the supporting device 3, a rolling device 5 is symmetrically arranged on the outside of the blank 2, a radial feed hydraulic cylinder assembly 4 is connected to the outside of the rolling device 5 in the horizontal direction, and an axial feed hydraulic cylinder assembly 6 is connected to the outside of the rolling device 5 in the vertical direction, and the axial feed hydraulic cylinder assembly 6 is connected to a servo motor 7.

[0008] The supporting device 3 includes a pair of pressing plates 301, which support the blank 2 from above and below respectively, and are fixed on the workbench 1 through locking nuts 303 and pads 302. The blank 2 rotates around its own axis along with the workbench 1.

[0009] The rolling device 5 includes a rolling die 502, which is installed on the die frame 501 through a rolling die shaft 503. The rolling die 502 is arranged in a different plane from the axis of the blank 2, and the rolling die shaft 503 is connected to the oil motor 504; the radial feed hydraulic cylinder assembly 4 and the axial feed hydraulic cylinder assembly 6 are respectively fixed to the die frame 501, respectively realizing the radial and axial feeding, exit movement and low-frequency vibration of the rolling die 502 along the blank 2.

[0010] The axial feed hydraulic cylinder assembly 6 includes a cylinder body 601 with both ends penetrated, and a first piston 606 and a second piston 609 are installed in the cylinder body 601; a hydraulic rod 605 is installed on the first piston 606, and the hydraulic rod 605 passes through the first end cover 604, and the first end cover 604 seals one end of the cylinder body 601; a second piston 609 is installed at the other end of the cylinder body 601, and a follower shaft disc 612 is installed on the second piston 609, and the follower shaft disc 612 is fixedly connected to the second piston 609 by a nut 607 and a washer 608. The follower shaft disc 612 passes through the second end cover 610, and the second end cover 610 seals the other end of the cylinder body 601; a return spring 611 is installed on the shaft of the follower shaft disc 612 extending out of the second end cover 610; a plurality of balls 614 are installed between the follower shaft disc 612 and the end face cam 615, and the balls 614 are fixed in the disc end groove of the follower shaft disc 612 by a retainer 613;

[0011] The cylinder body 601 is provided with a first oil port 602 and a second oil port 603 . The first oil port 602 is located in the chamber between the first piston 606 and the second piston 609 . The second oil port 603 is located in the chamber between the first piston 606 and the first end cover 604 .

[0012] The end face cam 615 is driven to rotate by the servo motor 7, thereby pushing the follower shaft disc 612 to drive the second piston 609 to move back and forth in a straight line under the reset action of the reset spring 611, and the reciprocating frequency is 20Hz~30Hz; the reciprocating motion of the second piston 609 causes the oil pressure in the chamber between the second piston 609 and the first piston 606 in the cylinder 601 to fluctuate continuously, thereby realizing low-frequency vibration of the first hydraulic rod 605, thereby realizing low-frequency vibration of the rolling die 502 along the axial direction of the blank 2.

[0013] The rolling die 502 is in the shape of a worm, and realizes the rolling plastic forming of large-module gears through the forming movement between it and the blank 2; the total radial feed depth of the blank 2 is S0, and the number of passes used is m, m>1, to achieve progressive forming of the gear profile; during the progressive rolling forming process, the rolling die 502 not only feeds axially along the blank 2, but also vibrates at a low frequency along the feed direction.

[0014] A forming process of a forming device for semi-solid rolling large-module gears using a low-frequency vibration forming method includes the following steps:

[0015] Step 1: Place the forged or rolled gear blank 2 in an electric furnace or a medium frequency induction heating furnace for heating and heat preservation treatment at a heating temperature of 1355-1490° C. for a heat preservation time of 5-30 minutes, thereby obtaining a semi-solid gear blank 2;

[0016] Step 2: clamp the semi-solid tooth blank 2 on the workbench 1 and fix it with the support device 3;

[0017] Step 3: Start the oil motor 504 and the servo motor 7 to make the rolling die 502 rotate around its own axis and vibrate at a low frequency along the axial direction of the blank 2. The low frequency vibration frequency is controlled to be 20Hz to 30Hz. At the same time, the blank 2 rotates around its own axis on the workbench 1. The total radial feed of the rolling die 502 is S0, and the completed radial feed is S1. At this time, S1=0, the number of teeth of the gear to be processed is Z, and the speed of the rolling die 502 is ω 模 and the rotation speed ω of billet 2 坯 Satisfy the relationship shown in formula (1):

[0018]

[0019] Step 4: The rolling die 502 performs the first rolling process to form the gear profile, specifically:

[0020] 4.1. The radial feed hydraulic cylinder assembly 4 controls the radial feed amount of the rolling die 502 to be Δ; Δ is determined by the total radial feed amount S0 and the number of rolling passes m, and is specifically determined by referring to formula (2):

[0021]

[0022] 4.2. During the forming process, the rolling die 502 is kept rotating around its own axis and vibrating at a low frequency of 20 Hz to 30 Hz, while simultaneously performing axial feeding motion along the blank 2;

[0023] 4.3. The rolling die 502 is fed axially from one end to the other end of the blank 2 to complete the rolling forming of the entire gear profile under the radial feed amount Δ;

[0024] Step 5: Determine whether the total radial feed is completed. Refer to formula (3) for details:

[0025] S′1=S1+Δ (3)

[0026] In formula (3), S′1 represents the radial feed amount completed after the current rolling;

[0027] When the radial feed amount has been completed and is equal to the total radial feed amount of the rolling die 502, proceed to step 6;

[0028] When S′1<S0, adjust the radial feed of the rolling die 502 to increase its radial feed by Δ; repeat step 4 until the radial feed is equal to the total radial feed of the rolling die, and then proceed to step 6;

[0029] Step 6: After all m passes are completed, the gear profile rolling is completed, and the oil motor 504 and the servo motor 7 are turned off;

[0030] Step 7: The rolling die 502 moves back to the initial position to unload the blank 2.

[0031] Beneficial effects of the present invention:

[0032] (1) The present invention adopts low-frequency vibration to assist forming, which reduces forming load, reduces mold wear, and reduces energy consumption, and is suitable for plastic forming of large-module toothed parts.

[0033] (2) The present invention combines the semi-solid process to effectively reduce the resistance to plastic deformation, making the material easier to flow, which is beneficial to the tooth filling of large-module gears and effectively avoids the problem of tooth material shortage; and the semi-solid workpiece has a small, uniform, spherical microstructure, and the overall performance of the formed gear parts is excellent.

[0034] (3) The multi-pass progressive forming of the present invention has low friction, good plasticity, and low forming force, thus avoiding the defect of incomplete tooth shape and achieving high tooth shape forming accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is the front view of the device of the present invention.

[0036] Figure 2 Exploded view of the blank support device and workbench of the present invention.

[0037] Figure 3 It is a side view of the device of the present invention.

[0038] Figure 4 It is a cross-sectional view of the axial feed hydraulic cylinder assembly of the present invention along the axis.

[0039] Figure 5 It is the front view of the rolling die of the present invention.

[0040] Figure 6 It is a schematic diagram of the first tooth profile forming process of the present invention.

[0041] Figure 7 This is a schematic diagram of the first tooth profile after forming according to the present invention.

[0042] Figure 8 This is a schematic diagram of the gear profile rolling process of the present invention. DETAILED DESCRIPTION

[0043] The present invention will be described clearly and completely below with reference to the embodiments and accompanying drawings.

[0044] Reference Figure 1 A forming device for semi-solid rolling of large-module gears using a low-frequency vibration forming method includes a workbench 1, a supporting device 3 is connected to the workbench 1, a blank 2 is mounted on the supporting device 3, a rolling device 5 is symmetrically arranged on the outside of the blank 2, a radial feed hydraulic cylinder assembly 4 is connected to the outside of the rolling device 5 in the horizontal direction, and an axial feed hydraulic cylinder assembly 6 is connected to the outside of the rolling device 5 in the vertical direction, and the axial feed hydraulic cylinder assembly 6 is connected to the servo motor 7.

[0045] Reference Figure 1 and Figure 2 The blank 2 is rolled and formed in a semi-solid state and supported by a supporting device 3. The supporting device 3 includes a pair of pressing plates 301. The pair of pressing plates 301 support the blank 2 from the top and bottom respectively, and are fixed on the workbench 1 through locking nuts 303 and pads 302. The blank 2 rotates around its own axis with the workbench 1.

[0046] Reference Figure 1 and Figure 3The rolling device 5 includes a rolling die 502, which is installed on the die frame 501 through a rolling die shaft 503. The rolling die 502 is arranged in a different plane from the axis of the blank 2. The rolling die shaft 503 is connected to the oil motor 504, and the oil motor 504 drives the rolling die 502 to rotate around its own axis; the radial feed hydraulic cylinder assembly 4 and the axial feed hydraulic cylinder assembly 6 are respectively fixed to the die frame 501, respectively realizing the radial and axial feeding, withdrawal movement and low-frequency vibration of the rolling die 502 along the blank 2.

[0047] Reference Figure 4 In order to realize the axial feeding, withdrawal movement and low-frequency vibration of the rolling die 502 along the blank 2, the axial feeding hydraulic cylinder assembly 6 includes a cylinder body 601 with both ends penetrated, and the cylinder body 601 is equipped with a first piston 606 and a second piston 609; the first piston 606 is equipped with a hydraulic rod 605, and the hydraulic rod 605 passes through the first end cover 604, and the first end cover 604 seals one end of the cylinder body 601; the other end of the cylinder body 601 is equipped with a second piston 609, and the second piston 609 is equipped with a follower shaft disc 612, which follows the cylinder body 601. The shaft disc 612 is fixedly connected to the second piston 609 via a nut 607 and a washer 608. The follower shaft disc 612 passes through the second end cap 610, which seals the other end of the cylinder body 601. A return spring 611 is mounted on the shaft of the follower shaft disc 612 extending outside the second end cap 610. A plurality of balls 614 are mounted between the follower shaft disc 612 and the end cam 615. The balls 614 are secured in the end grooves of the follower shaft disc 612 by a retainer 613 to reduce friction during the movement of the end cam 615.

[0048] The cylinder body 601 is provided with a first oil port 602 and a second oil port 603. The first oil port 602 is located in the chamber between the first piston 606 and the second piston 609, and the second oil port 603 is located in the chamber between the first piston 606 and the first end cover 604. By controlling the oil inlet and outlet of the first oil port 602 and the second oil port 603, the hydraulic rod 605 is extended or retracted, thereby driving the rolling die 502 to move synchronously, thereby achieving the feeding or withdrawal movement of the rolling die 502 along the axial direction of the blank 2.

[0049] The end face cam 615 is driven to rotate by the servo motor 7, thereby pushing the follower shaft disc 612 to drive the second piston 609 to move back and forth in a straight line under the reset action of the reset spring 611, and the reciprocating frequency is 20Hz~30Hz; the reciprocating motion of the second piston 609 causes the oil pressure in the chamber between the second piston 609 and the first piston 606 in the cylinder 601 to fluctuate continuously, thereby realizing low-frequency vibration of the first hydraulic rod 605, thereby realizing low-frequency vibration of the rolling die 502 along the axial direction of the blank 2.

[0050] Reference Figure 5The rolling die 502 is in the shape of a worm, and the rolling plastic forming of the large module gear is achieved through the forming movement between the blank 2 and the rolling die 502; the total radial feed depth of the blank 2 is S0, and the number of passes used is m, m>1, so as to achieve the progressive forming of the gear profile; in the progressive rolling forming process, the rolling die 502 not only feeds along the axial direction of the blank 2, but also makes low-frequency vibration along the feed direction, thereby reducing the forming load and improving the tooth profile accuracy. The formed tooth profile is standard. This rolling forming process can form large module gear profiles with small forming force and high forming efficiency. The formed parts have continuous tissue fibers, high forming accuracy, and high part reliability.

[0051] A forming process of a forming device for semi-solid rolling large-module gears using a low-frequency vibration forming method includes the following steps:

[0052] Step 1: Place the forged or rolled gear blank 2 in an electric furnace or a medium frequency induction heating furnace for heating and heat preservation treatment at a temperature of 1355-1490° C. for 5-30 minutes, thereby obtaining a semi-solid gear blank 2 having a fine, uniform, spherical microstructure;

[0053] Step 2: clamp the semi-solid tooth blank 2 on the workbench 1 and fix it with the support device 3;

[0054] Step 3, refer to Figure 3 , start the oil motor 504 and the servo motor 7, so that the rolling die 502 rotates around its own axis and vibrates at a low frequency along the axial direction of the blank 2, and the low frequency vibration frequency is controlled to be 20Hz~30Hz. At the same time, the blank 2 rotates around its own axis on the workbench 1; the total radial feed amount of the rolling die 502 is S0, the completed radial feed amount is S1, at this time S1=0, the number of teeth of the gear to be processed is Z, and the speed of the rolling die 502 is ω 模 and the rotation speed ω of billet 2 坯 Satisfy the relationship shown in formula (1):

[0055]

[0056] Step 4: The rolling die 502 performs the first rolling process to form the gear profile, specifically:

[0057] 4.1. The radial feed hydraulic cylinder assembly 4 controls the radial feed amount of the rolling die 502 to be Δ; Δ is determined by the total radial feed amount S0 and the number of rolling passes m, and is specifically determined by referring to formula (2):

[0058]

[0059] 4.2. Reference Figure 6During the forming process, the rolling die 502 is kept rotating around its own axis and vibrating at a low frequency of 20 Hz to 30 Hz, while making an axial feed motion along the blank 2;

[0060] 4.3. Reference Figure 7 , the rolling die 502 is axially fed from one end to the other end along the axial direction of the blank 2 to complete the rolling forming of the entire gear profile under the radial feed amount Δ;

[0061] Step 5: Determine whether the total radial feed is completed. Refer to formula (3) for details:

[0062] S′1=S1+Δ (3)

[0063] In formula (3), S′1 represents the radial feed amount completed after the current rolling;

[0064] When the radial feed amount has been completed and is equal to the total radial feed amount of the rolling die 502, proceed to step 6;

[0065] When S′1<S0, adjust the radial feed of the rolling die 502 to increase its radial feed by Δ; repeat step 4 until the radial feed is equal to the total radial feed of the rolling die, and then proceed to step 6;

[0066] Step 6, refer to Figure 8 After all m passes are completed, the gear profile rolling forming is completed, and the oil motor 504 and the servo motor 7 are turned off;

[0067] Step 7: The rolling die 502 moves back to the initial position to unload the blank 2.

[0068] The above are merely embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention description and drawings, or directly or indirectly applied to other related system fields, are within the scope of protection of the present invention.

Claims

1. A forming device for semi-solid rolling large-module gears using a low-frequency vibration forming method, comprising a workbench (1), characterized in that: A support device (3) is connected to the workbench (1), a blank (2) is mounted on the support device (3), a rolling device (5) is symmetrically arranged on the outside of the blank (2), a radial feed hydraulic cylinder assembly (4) is connected to the outside of the rolling device (5) in a horizontal direction, an axial feed hydraulic cylinder assembly (6) is connected to the outside of the rolling device (5) in a vertical direction, and the axial feed hydraulic cylinder assembly (6) is connected to a servo motor (7); The axial feed hydraulic cylinder assembly (6) includes a cylinder body (601) with both ends passing through it, a first piston (606) and a second piston (609) are installed in the cylinder body (601); a hydraulic rod (605) is installed on the first piston (606), and the hydraulic rod (605) passes through the first end cover (604), and the first end cover (604) seals one end of the cylinder body (601); a second piston (609) is installed on the other end of the cylinder body (601), and a follower shaft disc (612) is installed on the second piston (609). The follower shaft disc (612) ) is fixedly connected to the second piston (609) through a nut (607) and a washer (608); the follower shaft disc (612) passes through the second end cover (610), and the second end cover (610) seals the other end of the cylinder body (601); a return spring (611) is installed on the shaft of the follower shaft disc (612) extending outside the second end cover (610); a plurality of balls (614) are installed between the follower shaft disc (612) and the end face cam (615), and the balls (614) are fixed in the disc end groove of the follower shaft disc (612) by a retainer (613); The cylinder body (601) is provided with a first oil port (602) and a second oil port (603), wherein the first oil port (602) is located in a chamber between the first piston (606) and the second piston (609), and the second oil port (603) is located in a chamber between the first piston (606) and the first end cover (604); The end cam (615) is driven to rotate by the servo motor (7), thereby pushing the follower shaft disc (612) to drive the second piston (609) to reciprocate linearly under the reset action of the reset spring (611), with a reciprocating frequency of 20Hz to 30Hz; the reciprocating motion of the second piston (609) causes the oil pressure in the chamber between the second piston (609) and the first piston (606) in the cylinder body (601) to fluctuate continuously, thereby realizing low-frequency vibration of the hydraulic rod (605), thereby realizing low-frequency vibration of the rolling die (502) along the axial direction of the blank (2).

2. The device according to claim 1, characterized in that: The supporting device (3) includes a pair of pressing plates (301), which support the blank (2) from above and below respectively, and are fixed on the workbench (1) through locking nuts (303) and pads (302). The blank (2) rotates around its own axis along with the workbench (1).

3. The device according to claim 1, characterized in that: The rolling device (5) includes a rolling die (502), which is mounted on a die frame (501) via a rolling die shaft (503). The rolling die (502) is arranged in a non-planar manner with respect to the axis of the blank (2), and the rolling die shaft (503) is connected to an oil motor (504). A radial feed hydraulic cylinder assembly (4) and an axial feed hydraulic cylinder assembly (6) are respectively fixedly connected to the die frame (501), respectively realizing the radial and axial feeding and withdrawal movements and low-frequency vibration of the rolling die (502) along the blank (2).

4. The device according to claim 3, characterized in that: The rolling die (502) is in the shape of a worm and realizes rolling plastic forming of a large module gear through the forming motion between the rolling die and the blank (2); the total radial feed depth of the blank (2) is S0, and the number of passes used is m, m>1, so as to realize the progressive forming of the gear profile; during the progressive rolling forming process, the rolling die (502) not only feeds along the axial direction of the blank (2), but also performs low-frequency vibration along the feed direction.

5. A forming process for a forming device for semi-solid rolling large-module gears using a low-frequency vibration forming method according to any one of claims 1 to 4, comprising the following steps: Step 1: Place the forged or rolled gear blank (2) in an electric furnace or a medium frequency induction heating furnace for heating and heat preservation treatment at a heating temperature of 1355-1490° C. for a heat preservation time of 5-30 minutes, thereby obtaining a semi-solid gear blank (2); Step 2: clamping the semi-solid blank (2) on the workbench (1) and fixing it with a supporting device (3); Step 3, start the oil motor (504) and the servo motor (7), so that the rolling die (502) rotates around its own axis and vibrates at a low frequency along the axial direction of the blank (2), and the low frequency vibration frequency is controlled to be 20Hz to 30Hz. At the same time, the blank (2) rotates around its own axis on the workbench (1); the total radial feed amount of the rolling die (502) is S0, the completed radial feed amount is S1, at this time S1=0, the number of teeth of the gear to be processed is Z, and the speed of the rolling die (502) is ω 模 and the rotation speed ω of the blank (2) 坯 Satisfy the relationship shown in formula (1): Step 4, the rolling die (502) is used to roll the gear profile for the first time, specifically: 4.

1. The radial feed hydraulic cylinder assembly (4) controls the radial feed amount of the rolling die (502) to be Δ; Δ is determined by the total radial feed amount S0 and the number of rolling passes m, and is specifically determined by referring to formula (2): 4.

2. During the forming process, the rolling die (502) is kept rotating around its own axis and vibrating at a low frequency of 20 Hz to 30 Hz, while simultaneously performing axial feeding motion along the blank (2); 4.

3. The rolling die (502) is axially fed from one end to the other end along the axial direction of the blank (2), completing the rolling forming of the entire gear profile under the radial feed amount Δ; Step 5: Determine whether the total radial feed is completed. Refer to formula (3) for details: S′1=S1+Δ (3) In formula (3), S′1 represents the radial feed amount completed after the current rolling; When the radial feed amount has been completed and is equal to the total radial feed amount of the rolling die (502), proceed to step 6; When S′1<S0, the radial feed of the rolling die (502) is adjusted to increase the radial feed by Δ; step 4 is repeated until the radial feed is equal to the total radial feed of the rolling die, and then step 6 is entered; Step 6: After all m passes are completed, the gear profile rolling forming is completed, and the oil motor (504) and the servo motor (7) are turned off; Step 7: The rolling die (502) moves back to the initial position to unload the blank (2).

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