A processing method of a belt pulley inner tooth piece

Abstract

The application discloses a processing method of a pulley inner tooth piece. The pulley inner tooth piece comprises a main body part which is tubular and extends along a shape direction from a first end to a second end, the main body part is provided with an inner hole penetrating to both ends thereof, the inner hole is provided with inner teeth which are distributed in a circular array around a central axis of the main body part at the first end, and a middle part of the inner hole is provided with an internal thread; a flange is arranged at the first end of the main body part, the flange is provided with a limiting groove which faces the second end, the limiting groove surrounds the flange for one turn, the groove depth of the limiting groove changes monotonously, and the limiting groove is provided with a limiting convex point. The spiral inclined surface and the limiting convex point arranged on the flange of the pulley inner tooth piece can adapt to the end face shape of the spring and limit the rotation of the spring, and the installation stability is better. The processing method of the pulley inner tooth piece combines cold heading and vertical forging processes, and improves the production efficiency during mass production. The application relates to the field of automobile manufacturing.

Description

Technical Field

[0001] This invention relates to a method for machining internal gears in pulleys in the field of automobile manufacturing. Background Technology

[0002] Currently, the internal gears of engine pulleys used in the automotive industry are generally tubular, with teeth in the inner hole to mesh with other external components, and a flange on the outer side. A spring is sleeved on the outer side of the internal gears of the pulley and abuts against the flange.

[0003] Because of the complex shape of the internal gear components of the pulley, the production process generally includes a series of machining processes such as cutting and gear hobbing, which makes the production cycle of the internal gear components long and the production cost of the parts high, which is not conducive to large-scale production.

[0004] Furthermore, the contact surface between the flange and the spring on the internal gear of the pulley is currently flat. The end face of the spring needs to be adapted to be flat to improve the contact stability between the two. Otherwise, unstable contact can easily lead to spring slippage, which undoubtedly increases the requirements for the spring manufacturing process. Moreover, during the operation of the car, the spring is prone to vibration and rotation, increasing the wear on the flange. Summary of the Invention

[0005] The purpose of this invention is to at least solve one of the technical problems existing in the prior art, and to provide a method for processing the internal gear of a pulley, which can improve the installation stability of the spring and the internal gear, and improve the production efficiency during mass production.

[0006] According to an embodiment of the present invention, a method for machining an internal gear component of a pulley is provided, the internal gear component of the pulley comprising:

[0007] The main body is tubular and extends from the first end to the second end along the body direction. The main body is provided with an inner hole that extends through both ends. The inner hole is provided with internal teeth arranged in a circumferential array around the central axis of the main body at the first end. The middle part of the inner hole is provided with an internal thread.

[0008] A flange is provided at the first end of the main body. The flange has a limiting groove facing the second end. The limiting groove surrounds the flange and the depth of the limiting groove changes monotonically. The limiting groove has a limiting protrusion.

[0009] The manufacturing method for the internal gear component of the pulley includes the following steps:

[0010] A blank that matches the length of the teeth inside the pulley is obtained using a cutting device;

[0011] Chamfers are formed at both ends of the blank;

[0012] The blank is reverse-extruded into an inner hole using a cold heading machine;

[0013] A pre-formed flange is made at one end of the blank;

[0014] The flange is shaped;

[0015] Remove excess waste material from the blank along the inner hole;

[0016] The limiting groove and the limiting protrusion are formed by a vertical forging machine;

[0017] The surface of the blank is machined by cutting on a lathe;

[0018] The internal teeth are obtained by forging one end of the inner hole;

[0019] The internal thread is obtained by thread cutting in the middle of the inner hole.

[0020] According to an embodiment of the present invention, the number of internal teeth is further 18.

[0021] According to an embodiment of the present invention, the flange is further provided with a transmission groove on its side, the transmission groove being used to contact the belt to transmit power.

[0022] According to an embodiment of the present invention, the cold heading equipment further includes a cold heading die assembly, a cold heading punch assembly, and a cold heading main die. The cold heading die assembly includes a cold heading die holder capable of accommodating the cold heading main die and the blank. The cold heading punch assembly is movable relative to the cold heading die assembly and extends into the cold heading die holder to apply a force to the blank.

[0023] According to an embodiment of the present invention, the cold heading main die is detachably connected to the cold heading die holder.

[0024] According to an embodiment of the present invention, the vertical forging equipment further includes a vertical forging die assembly and a vertical forging punch. The vertical forging die assembly includes a vertical forging die holder capable of accommodating the blank. The vertical forging punch is movable relative to the vertical forging die assembly and extends into the vertical forging die holder to apply force to the blank. The end of the vertical forging punch is helical and has a concave point.

[0025] According to an embodiment of the present invention, before cutting the blank using a cutting device, the wire is first straightened by a straightening wheel.

[0026] According to an embodiment of the present invention, the blank is further annealed before vertical forging to eliminate internal stress and improve elongation.

[0027] According to an embodiment of the present invention, before vertical forging, the surface of the blank is phosphated to reduce the friction on the inner wall of the mold during the forging process.

[0028] The beneficial effects of the embodiments of the present invention include at least the following: by setting a spiral inclined surface and a limiting protrusion on the flange of the inner toothed part of the pulley, the present invention can adapt to the inclined end face shape of the spring and limit the rotation of the spring, thus having better installation stability; moreover, the present invention also proposes a processing method for the inner toothed part of the pulley, which combines cold heading and vertical forging processes to improve production efficiency during mass production. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly explained below. Obviously, the described drawings are only a part of the embodiments of the present invention, and not all of them. Those skilled in the art can obtain other design schemes and drawings based on these drawings without creative effort.

[0030] Figure 1 These are a side sectional view and a three-dimensional view of the internal gear of the pulley according to an embodiment of the present invention;

[0031] Figure 2 This is a schematic diagram of steps a to e in the processing method of this embodiment of the invention;

[0032] Figure 3 This is a schematic diagram of steps f to j in the processing method of this embodiment of the invention;

[0033] Figure 4 This is a schematic diagram of steps k to n in the processing method of this embodiment of the invention;

[0034] Figure 5 This is a structural diagram of the cold heading equipment used in the processing method of this invention embodiment;

[0035] Figure 6 This is a structural diagram of the vertical forging equipment used in the processing method of this invention.

[0036] Reference numerals: 100-Main body, 110-First end, 120-Second end, 130-Inner hole, 131-Internal tooth, 132-Internal thread, 200-Flange, 210-Limiting groove, 220-Limiting protrusion, 230-Transmission groove, 300-Blank, 400-Cold heading equipment, 410-Cold heading die assembly, 411-Cold heading die base, 412-Cold heading die ejector pin base, 413-Cold heading die ejector pin 414-Cold forging die ejector tube, 420-Cold forging punch assembly, 421-Cold forging punch head, 422-Cold forging punch ejector rod, 423-Cold forging punch shell, 424-Cold forging punch ejector rod seat, 430-Cold forging main die, 500-Vertical forging equipment, 510-Vertical forging die assembly, 511-Vertical forging die seat, 512-Vertical forging die ejector rod, 513-Vertical forging die ejector tube, 520-Vertical forging punch head. Detailed Implementation

[0037] This section will describe in detail specific embodiments of the present invention. Preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the drawings is to supplement the textual description with graphics, so that people can intuitively and vividly understand each technical feature and overall technical solution of the present invention, but they should not be construed as limiting the scope of protection of the present invention.

[0038] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0039] In the description of this invention, "several" means one or more, "more than" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0040] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0041] This invention provides an internal gear component for a pulley, which is used to engage with a pulley in an automobile to achieve transmission. Traditional internal gear components for pulleys have a flat flange surface for mounting with a spring. To ensure stable assembly between the spring and the flange, the spring's end needs to be machined into a flat surface, undoubtedly increasing the processing complexity. Furthermore, if assembly deviations result in a gap between the spring and the flange, the spring is prone to vibration and rotation during vehicle operation, affecting the flange's lifespan and the spring's performance. Therefore, this internal gear component for the pulley features a limiting groove 210 at the flange 200, allowing the spring to be positioned within it for limiting its movement. The groove depth of the limiting groove 210 is monotonically variable, causing its inner surface to rise in a spiral slope, conforming to the spring's trajectory and eliminating the need for further end machining. To reduce spring rotation, the limiting groove 210 also includes limiting protrusions 220 to increase friction when in contact with the spring.

[0042] This invention also provides a processing method for producing the aforementioned internal gear of a pulley. It combines cold heading and vertical forging processes and proposes a vertical forging punch 520 capable of pressing out a special structure limiting groove 210 in the vertical forging process, which can improve production efficiency while meeting dimensional accuracy requirements.

[0043] Reference Figure 1 ( Figure 1 a is a side sectional view of the internal gear of this pulley. Figure 1 (b is a three-dimensional view of the internal gear component of this pulley). The internal gear component of the pulley in this embodiment of the invention includes a main body 100 and a flange 200, which are integrally formed. The main body 100 is tubular and extends from a first end 110 to a second end 120 along its shape. An inner hole 130 is provided inside the main body 100, and both ends of the inner hole 130 extend to both ends of the main body 100. The inner hole 130 has internal teeth 131 arranged in a circumferential array around the central axis of the main body 100 at the first end, and an internal thread 132 is provided in the middle of the inner hole 130. The internal teeth 131 are used to mesh with external structures to achieve transmission, and the number of teeth is specifically 18. The internal thread 132 is used to connect with external structures by threads to achieve fixation.

[0044] A flange 200 is located at the first end 110 of the main body 100. The flange 200 has a limiting groove 210 facing the second end 120. The limiting groove 210 surrounds the flange 200, and its depth monotonically changes. In this application, monotonically changing means including both monotonically increasing and monotonically decreasing cases, indicating that the limiting groove 210 surrounds the flange 200 with its depth monotonically increasing or decreasing, forming a spiral ramp structure. A limiting protrusion 220 is also provided in the limiting groove 210 for abutting against the end of the spring to limit the spring's rotation.

[0045] Furthermore, the flange 200 is also provided with a transmission groove 230 on its side, which is used to contact the belt to form a belt drive, thereby realizing power transmission.

[0046] The processing method in this embodiment of the invention is used to produce the aforementioned internal gear component of the pulley, and specifically includes the following steps:

[0047] S100. Reference Figure 2 a. Use a cutting device to cut and obtain a blank 300 that matches the length of the teeth inside the pulley;

[0048] S200. Reference Figure 2 b. Chamfer both ends of the 300 blank to prepare for subsequent cold heading and extrusion;

[0049] S300. Reference Figure 2 c. The blank 300 is back-extruded into an inner hole using a cold heading machine 400, and the inner hole 130 is then machined using this hole position as a calibration.

[0050] S400. Reference Figure 2 d. Pre-form flange 200 at one end of blank 300. Blank 300 is made of DC53 material and is heat-treated and tempered three times to control the hardness at HRC59-60 degrees.

[0051] S500. Reference Figure 2 e. Shape the flange 200 and preliminarily machine the outline of the limiting groove 210;

[0052] S600. Reference Figure 3 f and Figure 3 g. Remove excess waste material from blank 300 along the inner hole 130 and cut off the excess part of blank 300.

[0053] S700. Reference Figure 3 h, the limiting groove 210 and the limiting protrusion 220 are formed by vertical forging equipment;

[0054] S800. Reference Figure 3 i. Using the inner hole 130 as the clamping part, the surface of the blank 300 is machined by a lathe to improve dimensional accuracy;

[0055] S900. Reference Figure 3 j. Using the surface of the blank 300 as the clamping part, one end of the inner hole 130 is forged to obtain the inner tooth 131.

[0056] S1000. Reference Figure 4 k to Figure 4n. The surface of the blank 300 is precision machined by turning on a lathe, and the inner hole 130 is threaded in the middle to obtain the internal thread 132.

[0057] The finished products are then subjected to flaw detection and sorting to separate qualified and unqualified products. Qualified products undergo ultrasonic cleaning, are then coated with anti-rust oil, and packaged for storage.

[0058] Specifically, refer to Figure 5 The cold heading equipment 400 includes a cold heading die assembly 410, a cold heading punch assembly 420, and a cold heading main die 430. The cold heading die assembly includes a cold heading die base 411, a cold heading die ejector pin base 412, a cold heading die ejector pin 413, and a cold heading die push tube 414, which can accommodate the cold heading main die 430 and the blank 300. During installation, the cold heading die ejector pin base 412 supports the cold heading die ejector pin 413 and the cold heading die push tube 414. After the cold heading main die 430 is placed in the cold heading die base 411, the cold heading die ejector pin 413 and the cold heading die push tube 414 can directly contact the blank 300 and apply force. The cold heading punch assembly 420 includes a cold heading punch 421, a cold heading punch ejector pin 422, a cold heading punch die shell 423, and a cold heading punch ejector pin seat 424. The cold heading punch die shell 423 is the outer shell of the cold heading punch assembly 420. The cold heading punch ejector pin seat 424 is located at the top and transmits the force to the blank 300 through the cold heading punch 421 and the cold heading punch ejector pin 422, thereby extruding the blank 300 together with the cold heading die assembly 410.

[0059] The cold heading die assembly 410 and the cold heading punch assembly 420 are respectively connected to an external power device and can move relative to each other to adjust the distance between them. The cold heading punch assembly 420 can extend into the cold heading die holder 411 to apply force to the blank 300. The blank 300 is deformed by force in the cold heading die holder 411 and finally adapts to the shape of the die.

[0060] Furthermore, the cold heading main die 430 is a high-speed steel + surface chromium aluminum titanium steel sleeve spare part. The interference of this spare part is 0.1. It is detachably connected to the cold heading die base 411 and can be replaced, reducing the cost of the die.

[0061] Specifically, refer to Figure 6The vertical forging equipment 500 includes a vertical forging die assembly 510 and a vertical forging punch 520. The vertical forging die assembly 510 includes a vertical forging die base 511 capable of accommodating a blank 300, a vertical forging die ejector pin 512, and a vertical forging die push tube 513. Both the vertical forging die ejector pin 512 and the vertical forging die push tube 513 can contact the blank 300 placed in the vertical forging die base 511 and transmit force. The vertical forging punch 520 can move relative to the vertical forging die assembly 510 and extend into the vertical forging die base 511 to apply force to the blank 300. The end of the vertical forging punch 520 is helical and has a concave point, which can guide the blank 300 to form a helical groove 210 and a limiting protrusion 220 during the extrusion process. The vertical forging punch 520 is made of DC53 material, with a surface roughness controlled above Ra0.05 and a heat treatment hardness controlled at HRC59-60, effectively improving the die life.

[0062] Furthermore, before cutting the blank 300 using the cutting equipment, the wire is first straightened by a straightening wheel to improve the straightness of the finished product.

[0063] Furthermore, before vertical forging, the blank 300 is annealed to eliminate internal stress and increase elongation, which is beneficial for the blank 300 to be deformed under pressure during forging.

[0064] Furthermore, before vertical forging, the surface of the blank 300 is phosphated to reduce the friction on the surface of the blank 300 and reduce the mutual friction between the blank 300 and the inner wall of the mold during the forging process.

[0065] The above is a detailed description of the preferred embodiments of the present invention. However, the present invention is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention. All such equivalent modifications or substitutions are included within the scope defined by the claims of this application.

Claims

1. A method for machining the internal gear of a pulley, characterized in that: The internal gear of the pulley includes: The main body (100) is tubular and extends from the first end (110) to the second end (120) along the body direction. The main body (100) is provided with an inner hole (130) that extends through both ends. The inner hole (130) has internal teeth (131) arranged in a circumferential array around the central axis of the main body (100) at the first end (110). The middle part of the inner hole (130) is provided with an internal thread (132). A flange (200) is provided at the first end of the main body (100). The flange (200) is provided with a limiting groove (210) facing the second end (120). The limiting groove (210) surrounds the flange (200) and the groove depth of the limiting groove (210) changes monotonically. The limiting groove (210) is provided with a limiting protrusion (220). The machining method for manufacturing the internal gear of the pulley includes the following steps: A blank (300) matching the length of the inner tooth of the pulley is obtained using a cutting device. Chamfers are formed at both ends of the blank (300); The blank (300) is reverse-extruded into an inner hole using a cold heading machine (400); A pre-formed flange (200) is provided at one end of the blank (300); The flange (200) is shaped; Remove excess waste material from the blank (300) along the inner hole (130); The limiting groove (210) and the limiting protrusion (220) are formed by a vertical forging machine (500). The surface of the blank (300) is machined by cutting on a lathe; The internal teeth (131) are obtained by forging one end of the inner hole (130). The inner hole (130) is threaded in the middle to obtain the inner thread (132).

2. The method for machining the internal gear of the pulley according to claim 1, characterized in that: The number of internal teeth (131) is 18.

3. The method for machining the internal gear of the pulley according to claim 1, characterized in that: The flange (200) has a transmission groove (230) on its side, which is used to contact the belt to transmit power.

4. The method for machining the internal gear of the pulley according to claim 1, characterized in that: The cold heading equipment (400) includes a cold heading die assembly (410), a cold heading punch assembly (420), and a cold heading main die (430). The cold heading die assembly (410) includes a cold heading die holder (411) capable of accommodating the cold heading main die (430) and the blank (300). The cold heading punch assembly (420) is movable relative to the cold heading die assembly (410) and extends into the cold heading die holder (411) to apply force to the blank (300).

5. The method for machining the internal gear of the pulley according to claim 4, characterized in that: The cold heading main mold (430) and the cold heading die base (411) are detachably connected.

6. The method for machining the internal gear of a pulley according to claim 1, characterized in that: The vertical forging equipment (500) includes a vertical forging die assembly (510) and a vertical forging punch (520). The vertical forging die assembly (510) includes a vertical forging die holder (511) capable of accommodating the blank (300). The vertical forging punch (520) is movable relative to the vertical forging die assembly (510) and extends into the vertical forging die holder (511) to apply force to the blank (300). The end of the vertical forging punch (520) is helical and has a concave point.

7. The method for machining the internal gear of the pulley according to claim 1, characterized in that: Before cutting the blank (300) using the cutting equipment, the wire is first straightened by a straightening wheel.

8. The method for machining the internal gear of the pulley according to claim 1, characterized in that: Before vertical forging, the blank (300) is annealed to eliminate internal stress and improve elongation.

9. The method for machining the internal gear of a pulley according to claim 1, characterized in that: Before vertical forging, the surface of the blank (300) is phosphated to reduce the friction on the inner wall of the mold during forging.

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