A feeding and discharging structure of a gear hobbing machine

Abstract

The application provides a feeding and discharging structure of a gear hobbing machine, and belongs to the technical field of metal cutting machine tools, which comprises a rotating table, a plurality of supporting rods and a plurality of positioning assemblies, the rotating table is rotationally installed on a rack, the plurality of supporting rods are uniformly distributed on the circumferential side wall of the rotating table, the plurality of positioning assemblies are respectively arranged at the end portions of the plurality of supporting rods, a feeding assembly is used for conveying workpieces to the positioning assemblies at a feeding station, and a receiving assembly is used for receiving the workpieces falling from the positioning assemblies at a discharging station. When the rotating table rotates, the positioning assemblies at the end portions of the supporting rods are cyclically switched between the feeding station, the machining station and the discharging station, when one of the positioning assemblies positions a workpiece to the machining station through a centering unit, the positioning assemblies at other stations can simultaneously perform feeding or discharging, the waiting time of a traditional single-station device is avoided, manual feeding and discharging are not needed, and the workpiece replacement speed is improved.

Description

Technical Field

[0001] This invention relates to the field of metal cutting machine tool technology, and specifically to a loading and unloading structure for a gear hobbing machine. Background Technology

[0002] Gear hobbing machines are key pieces of equipment widely used in the gear machining industry. They machine gear teeth through the relative motion of the hobbing cutter and the workpiece. The loading and unloading processes, as pre- and post-processes of gear hobbing, directly affect gear machining efficiency, machining accuracy, and the level of automation. However, existing gear hobbing machines mostly rely on manual loading and unloading, with only a machining station. Workpieces need to be placed on the positioning device and clamped manually, followed by manual unloading, resulting in low production efficiency. While industrial robots can also perform loading and unloading, high-precision industrial robots are expensive to purchase. Summary of the Invention

[0003] To address the aforementioned technical shortcomings, the purpose of this invention is to provide a loading and unloading structure for a gear hobbing machine, which achieves automatic loading and unloading of the gear hobbing machine by setting up a loading component, a receiving component, and multiple positioning components.

[0004] To solve the above technical problems, the present invention adopts the following technical solution: The present invention provides a loading and unloading structure for a gear hobbing machine, comprising:

[0005] A rotary table, rotatably mounted on a machine frame;

[0006] Multiple support rods are evenly distributed on the circumferential sidewalls of the rotary table and are rotatably connected to the rotary table;

[0007] Multiple positioning components are respectively disposed at the ends of multiple support rods. Each positioning component includes a lower limit sleeve and a centering unit. The lower limit sleeve is rotatably mounted on the end of the support rod and has the freedom of axial movement. The centering unit is slidably mounted in the lower limit sleeve. When the rotary table rotates, the positioning components switch between three work positions: loading work position, processing work position, and unloading work position.

[0008] The feeding assembly is used to transport workpieces to the positioning assembly at the feeding station;

[0009] The receiving assembly is used to receive the workpiece falling from the positioning assembly at the unloading station;

[0010] The frame is equipped with a mandrel that is raised and lowered. Above the mandrel, a clamping shaft that is collinear with the axis of the mandrel is also raised and lowered on the frame. An upper limit sleeve is fixed at the bottom of the clamping shaft. When the positioning component is in the processing position, the positioning component is located above the mandrel. The mandrel and the clamping shaft move along the positioning component, respectively pressing the lower limit sleeve and the upper limit sleeve against the upper and lower ends of the workpiece. The lower limit sleeve and the upper limit sleeve cooperate to drive the centering unit to align the axis of the workpiece with the axis of the mandrel.

[0011] Preferably, the centering unit includes:

[0012] The central column is slidably installed in the lower limit sleeve;

[0013] Three positioning claws are evenly distributed around the central column. Each positioning claw is hinged to two parallel first links. The end of the first link away from the positioning claw is hinged to the central column.

[0014] A movable sleeve is fitted onto a central column. Three second connecting rods, each corresponding to the position of a positioning claw, are hinged to the movable sleeve. The second connecting rods are hinged to the first connecting rods adjacent to the positioning claws.

[0015] The flexible limiting mechanism, located on the central column, is used to push the movable sleeve to move and open the three positioning claws.

[0016] Preferably, the elastic limiting mechanism includes:

[0017] The fixed sleeve is fixed to the center column on the side of the movable sleeve away from the first connecting rod.

[0018] The first spring is sleeved on the central column between the fixed sleeve and the movable sleeve.

[0019] Preferably, a clamping sleeve is fitted on the central column between the first spring and the fixed sleeve, and the upper limit sleeve is provided with a step that cooperates with the clamping sleeve. During the process of the upper limit sleeve moving towards the lower limit sleeve, the step pushes the clamping sleeve to squeeze the first spring, so that the first spring pushes the movable sleeve to move, and the three positioning claws open and abut against the shaft hole of the workpiece.

[0020] Preferably, the clamping sleeve is provided with a centering conical ring, the upper limit sleeve is provided with a clearance hole that cooperates with the central column, and the step is provided with a conical surface that cooperates with the centering conical ring.

[0021] Preferably, the lower limiting sleeve has a through hole for the central column to pass through, the central column is slidably installed in the through hole, a limiting ring is fixed on the central column above the through hole, a second spring is sleeved on the central column between the limiting ring and the through hole, and a retaining ring is fixed at the end of the central column below the through hole.

[0022] Preferably, the positioning claw includes:

[0023] The vertical segment has a curved surface on the side away from the central column.

[0024] The support foot is fixed to the bottom of the vertical section and extends away from the central column;

[0025] A guide section is fixed to the top of the vertical section and tilted towards the central column.

[0026] Preferably, the feeding assembly includes a feeding conveyor with a baffle plate and a discharge port at the end of the feeding conveyor. The discharge port is located directly above the feeding station. After the feeding conveyor transports the workpiece to the discharge port, the workpiece falls into the centering unit through the discharge port and is placed on three positioning claws.

[0027] Preferably, a material ejection ring concentric with the rotary table is fixed on the frame. The material ejection ring has teeth and clearance grooves. A gear and a limiting frame are fixed on the support rod. At least two limiting wheels are rotatably mounted on the limiting frame. When the positioning component is in the loading or processing position, the corresponding limiting wheel abuts against the surface of the material ejection ring and restricts the rotation of the support rod. When the positioning component is in the unloading position, the gear meshes with the teeth, and the limiting wheel disengages from the material ejection ring under the action of the clearance groove.

[0028] Preferably, the receiving assembly includes a receiving conveyor, and a receiving section is provided at one end of the receiving conveyor located directly below the unloading station. The receiving section includes a baffle and a slider slidably mounted on the baffle. A roller frame is hinged to the slider, and multiple rollers are rotatably mounted on the roller frame. Multiple elastic elements are provided on the baffle for elastically supporting the slider and the roller frame. When the workpiece falls onto the roller, the roller frame rotates around the slider and compresses the elastic elements downward, conveying the workpiece onto the receiving conveyor.

[0029] The beneficial effects of this invention are as follows:

[0030] The rotary table of this invention, when rotating, drives the positioning components at the end of the support rod to cyclically switch between the loading station, processing station, and unloading station. When one of the positioning components positions the workpiece to the processing station via the centering unit, the mandrel and the clamping shaft cooperate to clamp the workpiece. At this time, the gear hobbing cutter of the gear hobbing machine can process the workpiece at the processing station, while the positioning components at other stations can simultaneously load or unload, avoiding the waiting time of traditional single-station equipment, eliminating the need for manual loading and unloading, and improving the material change speed. The mandrel and the clamping shaft can compress the first spring through the lower limit sleeve and the upper limit sleeve, and through the movable sleeve, the second connecting rod, and the first connecting rod, drive the three positioning claws to open synchronously, aligning the axis of the workpiece with the axis of the central column, and simultaneously aligning the axis of the central column with the axis of the clamping shaft and the mandrel. Axis alignment ensures coaxiality and gear precision during gear processing. By incorporating a first and second spring, after the positioning claw aligns the workpiece center, the lower and upper limit sleeves can continue to move and press against the upper and lower end faces of the workpiece, ensuring stable clamping. The invention includes a material ejection ring and a limiting wheel. When the support rod is at the loading and processing stations, the limiting wheel abuts against the upper surface of the material ejection ring, while the gear and its teeth do not mesh, preventing the support rod from rotating and ensuring positioning stability. When the support rod moves close to the unloading station, a clearance groove on the surface of the material ejection ring prevents interference between the limiting wheel and the ring. Simultaneously, the gear and its teeth mesh, driving the support rod to rotate, causing the centering unit to rotate 180°, turning the workpiece downwards. The workpiece then detaches from the positioning claw under its own weight, achieving automatic unloading. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of the overall structure of the loading and unloading structure of a gear hobbing machine provided in an embodiment of the present invention.

[0033] Figure 2 This is a perspective view of the rotary table, support rod, positioning components, and gear hobbing machine body in this invention.

[0034] Figure 3 for Figure 2 A magnified view of a portion of point A in the middle.

[0035] Figure 4 for Figure 2 A magnified view of a section at point B in the middle.

[0036] Figure 5This is a cross-sectional view of the workpiece being fitted onto the positioning unit in this invention.

[0037] Figure 6 This is a cross-sectional view of the workpiece clamped by the upper limit sleeve and the lower limit sleeve in this invention.

[0038] Figure 7 This is a schematic diagram illustrating the usage state of the present invention.

[0039] Explanation of reference numerals in the attached figures:

[0040] 1. Gear hobbing machine body; 2. Rotary table; 3. Support rod; 4. Positioning assembly; 5. Lower limit sleeve; 6. Centering unit; 61. Central column; 611. Limiting ring; 612. Retaining ring; 62. Positioning claw; 621. Vertical section; 622. Support foot; 623. Guide section; 63. First connecting rod; 64. Movable sleeve; 65. Second connecting rod; 66. Fixed sleeve; 67. First spring; 68. Pressing sleeve; 681. Centering cone ring; 6 9. Second spring; 7. Feeding assembly; 8. Receiving assembly; 9. Spindle; 10. Clamping shaft; 11. Upper limit sleeve; 111. Step; 112. Relief hole; 12. Feeding conveyor; 13. Baffle; 14. Drop port; 15. Unloading ring; 16. Toothed groove; 17. Relief groove; 18. Gear; 19. Limiting frame; 20. Limiting wheel; 21. Receiving conveyor; 22. Baffle wall; 23. Idler roller frame; 24. Elastic element. Detailed Implementation

[0041] The technical solutions of the embodiments 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.

[0042] Example 1:

[0043] like Figures 1 to 7 As shown, Embodiment 1 of the present invention provides a loading and unloading structure for a gear hobbing machine, which is set on one side of the gear hobbing machine body 1. This structure enables automatic loading, positioning, and unloading of workpieces, with each process occurring simultaneously. The gear hobbing cutter of the gear hobbing machine body 1 has degrees of freedom for lifting and horizontal movement, allowing it to be positioned close to the workpiece for machining. The present invention does not modify the gear hobbing machine body 1; the focus is on designing the corresponding loading and unloading structure.

[0044] The present invention designs a loading and unloading structure including a loading component 7, a receiving component 8, and a material changing component. The material changing component transfers the workpiece supplied by the loading component 7 to the front of the gear hobbing cutter for machining, and then transfers the machined workpiece to the receiving component 8 for unloading, completing the gear hobbing process. First, as... Figure 1 As shown, the present invention includes a column rotatably mounted on a frame via bearings, with a rotary table 2 fixedly mounted on the top of the column. A Geneva mechanism is installed within the frame, enabling the column to rotate intermittently by 120 degrees. The Geneva mechanism is driven by a servo motor, and the rotation interval can be set according to the processing time. How to drive the column to rotate intermittently, with each rotation being 120 degrees, is easily achieved using existing technology; therefore, the Geneva mechanism will not be described in detail in this invention.

[0045] Three support rods 3 are evenly distributed on the circumferential sidewall of the rotary table 2. One end of each support rod 3 is rotatably connected to the rotary table 2 via a bearing seat, allowing the support rod 3 to rotate around its own axis. The three support rods 3 are distributed at 120-degree intervals along the circumference of the rotary table 2. Each support rod 3 has a positioning component 4 at its end. The three positioning components 4 correspond to three different workstations. When the rotary table 2 rotates, the three positioning components 4 cyclically switch the corresponding workstation. The three workstations are the loading workstation, the machining workstation, and the unloading workstation. The positioning component 4 in the loading workstation is located below the loading component 7, the positioning component 4 in the machining workstation is located on the side of the gear hobbing cutter, and the positioning component 4 in the unloading workstation is located above the receiving component 8.

[0046] like Figure 3 , Figure 5 and Figure 6 As shown, the positioning component 4 of this invention includes a lower limit sleeve 5 and a centering unit 6 disposed on the lower limit sleeve 5. The lower limit sleeve 5 is mounted on the end of the support rod 3 via a linear bearing. The linear bearing allows the lower limit sleeve 5 to rotate at the end of the support rod 3 and also has the freedom to move along the axial direction of the lower limit sleeve 5. The axis of the support rod 3 is perpendicular to the axis of the rotary table 2, while the axis of the lower limit sleeve 5 is parallel to the axis of the rotary table 2.

[0047] The centering unit 6 includes a central post 61 and three positioning claws 62. The central post 61 is inserted into the through hole in the middle of the lower limit sleeve 5. The central post 61 can slide up and down in the through hole. To prevent the central post 61 from dislodging from the through hole when it moves upward, a retaining ring 612 is fixed at the end of the central post 61 below the through hole.

[0048] Three positioning claws 62 are evenly distributed circumferentially around the central column 61 at 120° intervals. Each positioning claw 62 comprises a vertical section 621, a support foot 622, and a guide section 623. The side of the vertical section 621 away from the central column 61 is an arc surface adapted to the shaft hole of the workpiece, and the radius of curvature of the arc surface matches the radius of the shaft hole of a common workpiece. The vertical section 621 is parallel to the central column 61. The support foot 622 is vertically fixed to the bottom of the vertical section 621 and extends horizontally to the side away from the central column 61 to support the workpiece. The guide section 623 is fixed to the top of the vertical section 621 and is inclined at 20° towards the central column 61 to form a constricted structure, which facilitates the smooth insertion of the workpiece.

[0049] Each positioning claw 62 is hinged with two parallel first connecting rods 63. The end of the first connecting rod 63 away from the positioning claw 62 is hinged to the middle of the central column 61 through a pin. The movable sleeve 64 is fitted on the upper part of the central column 61 and can slide along the central column 61. The outer circumference of the movable sleeve 64 is hinged with three second connecting rods 65. The three second connecting rods 65 correspond one-to-one with the three positioning claws 62. The end of the second connecting rod 65 away from the movable sleeve 64 is hinged to the first connecting rod 63 on the positioning claw 62 near the guide section 623, forming a parallelogram linkage mechanism to ensure that the positioning claws 62 can open or close synchronously and keep the vertical section 621 parallel to the central column 61.

[0050] like Figure 6 As shown, to ensure the centering unit 6 can stably hold the workpiece when it is placed on the centering unit 6, an elastic limiting mechanism is provided in the centering unit 6, including a fixed sleeve 66 and a first spring 67. The fixed sleeve 66 is fixed to the central column 61 by screws and is located on the side of the movable sleeve 64 away from the first connecting rod 63; the first spring 67 is sleeved on the central column 61, with its two ends abutting against the lower end face of the fixed sleeve 66 and the upper end face of the movable sleeve 64, respectively. In its natural state, the first spring 67 is in a slightly compressed state, pushing the movable sleeve 64 downward, so that the three positioning claws 62 remain in a moderately open initial state. When the feeding assembly 7 puts the workpiece onto the positioning claws 62, the shaft hole of the workpiece will be placed on the three positioning claws 62 from the guide section 623. Under the action of the workpiece's own weight, it can be driven by the guide section 623 to retract towards the central column 61, thus continuing to slide down until it is placed on the vertical section 621 and abuts against the support foot 622. The elasticity of the first spring 67 allows the vertical section 621 to basically adhere to the inner wall of the shaft hole.

[0051] With the above settings, the positioning component 4 can pick up and initially position the workpiece at the loading station. When the rotary table 2 rotates and moves the positioning component 4 to the processing station, the workpiece is then centered and clamped a second time.

[0052] A clamping shaft 10 and a spindle 9 are mounted on the frame, with the clamping shaft 10 positioned above the spindle 9, and the positioning assembly 4 located between the clamping shaft 10 and the spindle 9. The clamping shaft 10 acts as the driving shaft, and the axis of the spindle 9 is collinear with the axis of the clamping shaft 10, making the spindle 9 the driven shaft. The clamping shaft 10 and the spindle 9 cooperate to clamp the workpiece on the positioning assembly 4, and then the clamping shaft 10 rotates in conjunction with the gear hobbing cutter, causing the gear hobbing cutter to machine teeth on the workpiece. The lifting and rotating structure of the clamping shaft 10 and the spindle 9 can be implemented using existing technology.

[0053] A clamping sleeve 68 is fitted on the central post 61 between the first spring 67 and the fixed sleeve 66. The clamping sleeve 68 can slide freely along the central post 61. A centering conical ring 681 is provided on the upper part of the clamping sleeve 68. An upper limit sleeve 11 is fixed to the bottom of the abutting shaft 10. The upper limit sleeve 11 has a relief hole 112 in the middle that matches the central post 61 to avoid interference with the central post 61. A step 111 is provided inside the upper limit sleeve 11 near the relief hole 112. A conical surface that matches the centering conical ring 681 is provided on the step 111. The cone angle of the conical surface is the same as the cone angle of the centering conical ring 681 to ensure that the two can fit precisely. When the clamping shaft 10 moves towards the spindle 9, the step 111 engages with the centering cone ring 681 to align the shaft center. Simultaneously, it pushes the clamping sleeve 68 to compress the first spring 67. The first spring 67 elastically presses the movable sleeve 64, causing the movable sleeve 64 to drive the three positioning claws 62 to open synchronously via the second connecting rod 65 and the first connecting rod 63. This drives the workpiece to move, aligning the axis of the workpiece's shaft hole with the axis of the center column 61 and the clamping shaft 10. Afterward, the clamping shaft 10 continues to move downward until the upper limit sleeve 11 abuts against the upper end face of the workpiece.

[0054] A limiting ring 611 is fixed to the central post 61 on the upper side of the through hole of the lower limiting sleeve 5 by a snap ring. The limiting ring 611 and the retaining ring 612 together limit the maximum sliding stroke of the central post 61 on the lower limiting sleeve 5. A second spring 69 is sleeved on the central post 61 between the limiting ring 611 and the upper end face of the through hole. The two ends of the second spring 69 abut against the lower end face of the limiting ring 611 and the upper end face of the through hole, respectively. When the mandrel 9 moves upward, the tapered surface at the top of the mandrel 9 engages with the tapered surface at the bottom of the lower limiting sleeve 5 to center the lower limiting sleeve 5 and the mandrel 9. When the mandrel 9 continues to move upward, the mandrel 9 pushes the lower limiting sleeve 5 to compress the second spring 69 and move upward until the lower limiting sleeve 5 abuts against the lower end face of the workpiece. At this point, the clamping shaft 10 and the mandrel 9 cooperate to achieve positioning and clamping of the workpiece on the positioning assembly 4. Then the clamping shaft 10 rotates and drives the workpiece to rotate, cooperating with the gear hobbing cutter to complete the machining of the workpiece.

[0055] Example 2:

[0056] Based on Embodiment 1, to allow the machined workpiece to detach from the positioning assembly 4 at the unloading station, this invention includes a ejector ring 15 concentric with the rotary table 2 fixed on the frame. The ejector ring 15 is an annular structure, horizontally positioned below the support rod 3. The upper surface of the ejector ring 15 is a smooth plane, with a portion of its annular upper surface having teeth 16. The length of the teeth 16 corresponds to a 30° range before and after the unloading station. A limit frame 19 and a gear 18 are fixed on the support rod 3. The axis of the gear 18 coincides with the axis of the support rod 3, and its number of teeth matches the number of teeth in the teeth 16 of the ejector ring 15. When the gear 18 contacts the teeth 16, the gear 18 meshes with the teeth 16. Two limit wheels 20 are rotatably mounted on the limit frame 19. The two limit wheels 20 are symmetrically distributed on both sides of the support rod 3. A clearance groove 17 is provided on the ejector ring 15 corresponding to the unloading station and the position of the teeth 16.

[0057] When the support rod 3 is in the loading and processing positions, the outer circumferential surface of the limiting wheel 20 rolls in contact with the upper surface of the ejector ring 15, restricting the rotation of the support rod 3 and thus keeping the central column 61 parallel to the axis of the rotary table 2. When the support rod 3 follows the rotary table 2 to a position close to the unloading position, the limiting wheel 20 is in the relief groove 17 and no longer restricts the rotation of the support rod 3. The gear 18 on the support rod 3 also meshes with the tooth pattern 16. This causes the gear 18 to rotate along with the support rod 3 as the rotary table 2 continues to rotate, thus causing the central column 61 to begin to rotate. When the workpiece on the positioning claw 62 gradually begins to face downwards, the elasticity of the first spring 67 is insufficient to hold the workpiece. Under the action of the workpiece's own weight, the workpiece detaches from the positioning claw 62 and falls onto the receiving assembly 8 below, completing the unloading process. When the rotary table 2 continues to rotate at a certain angle, the gear 18 disengages from the tooth 16, and at the same time, the limiting wheel 20 re-rolls into contact with the upper surface of the ejector ring 15, restricting the rotation of the support rod 3. At this time, the central column 61 has also returned to a state parallel to the axis of the rotary table 2.

[0058] Example 3:

[0059] Based on Embodiment 1 and Embodiment 2, the receiving component 8 used in this embodiment of the invention includes a belt-type receiving conveyor 21. The receiving conveyor 21 has a receiving part at one end near the unloading station, and the receiving part is located directly below the unloading station.

[0060] like Figure 1As shown, the receiving section includes a ring of baffles 22 perpendicular to the conveying direction. Two vertical grooves are formed on the baffles 22, through which the sliders are slidably connected. One end of the idler frame 23 is hinged to the two sliders on both sides by two pins. Elastic elements 24 for elastically supporting the sliders are also provided in the grooves. Multiple idlers are rotatably mounted on the idler frame 23, their surfaces covered with a rubber layer to reduce rigid collisions with the workpiece. Two elastic elements 24, which are helical springs, are fixed on the baffles 22, corresponding to the bottom corners of the idler frame 23 furthest from the sliders. When the workpiece slides off the positioning claw 62, it lands on the idler roller, where the elastic elements 24 act as a buffer. The weight of the workpiece presses one end of the idler frame 23 downwards, causing it to rotate around the pins, thus tilting. This causes the workpiece to slide down the idler roller and finally onto the belt conveyor 21 via a row of transition rollers.

[0061] The feeding assembly 7 also includes a belt conveyor 12. The feeding conveyor 12 is oriented towards the feeding station, and baffles 13 are fixed on both sides along the feeding direction to prevent the workpiece from falling during the conveying process. A discharge port 14 is provided at the end of the feeding conveyor 12. The inner diameter of the discharge port 14 is slightly larger than the diameter of the workpiece. The lower part of the discharge port 14 is directly opposite the positioning assembly 4 of the feeding station. A downward-extending guide cylinder is also provided at the discharge port 14. The lower end of the guide cylinder extends above the centering unit 6 of the positioning assembly 4 to guide the workpiece to fall accurately onto the positioning claw 62, thus completing the feeding.

[0062] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A loading and unloading structure for a gear hobbing machine, characterized in that, include: A rotary table, rotatably mounted on a machine frame; Multiple support rods are evenly distributed on the circumferential sidewalls of the rotary table and are rotatably connected to the rotary table; Multiple positioning components are respectively disposed at the ends of multiple support rods. Each positioning component includes a lower limit sleeve and a centering unit. The lower limit sleeve is rotatably mounted on the end of the support rod and has the freedom of axial movement. The centering unit is slidably mounted in the lower limit sleeve. When the rotary table rotates, the positioning components switch between three work positions: loading work position, processing work position, and unloading work position. The feeding assembly is used to transport workpieces to the positioning assembly at the feeding station; The receiving assembly is used to receive the workpiece falling from the positioning assembly at the unloading station; The frame is equipped with a mandrel that is raised and lowered. Above the mandrel, a clamping shaft that is collinear with the axis of the mandrel is also raised and lowered on the frame. An upper limit sleeve is fixed to the bottom of the clamping shaft. When the positioning component is in the processing position, the positioning component is located above the mandrel. The mandrel and the clamping shaft move along the positioning component, respectively pressing the lower limit sleeve and the upper limit sleeve against the upper and lower ends of the workpiece. The lower limit sleeve and the upper limit sleeve cooperate to drive the centering unit to align the axis of the workpiece with the axis of the mandrel. The centering unit includes: The central column is slidably installed in the lower limit sleeve; Three positioning claws are evenly distributed around the central column. Each positioning claw is hinged to two parallel first links. The end of the first link away from the positioning claw is hinged to the central column. A movable sleeve is fitted onto a central column. Three second connecting rods, each corresponding to the position of a positioning claw, are hinged to the movable sleeve. The second connecting rods are hinged to the first connecting rods adjacent to the positioning claws. An elastic limiting mechanism, mounted on the central column, is used to push the movable sleeve to move and open the three positioning claws; The elastic limiting mechanism includes: The fixed sleeve is fixed to the center column on the side of the movable sleeve away from the first connecting rod. The first spring is sleeved on the central post between the fixed sleeve and the movable sleeve; A clamping sleeve is fitted on the central column between the first spring and the fixed sleeve. The upper limit sleeve is provided with a step that cooperates with the clamping sleeve. During the process of the upper limit sleeve moving towards the lower limit sleeve, the step pushes the clamping sleeve to squeeze the first spring, so that the first spring pushes the movable sleeve to move, and the three positioning claws open and abut against the shaft hole of the workpiece. The positioning claw includes: The vertical segment has a curved surface on the side away from the central column. The support foot is fixed to the bottom of the vertical section and extends away from the central column; A guide section is fixed to the top of the vertical section and tilted towards the central column.

2. The loading and unloading structure of a gear hobbing machine as described in claim 1, characterized in that, The clamping sleeve is provided with a centering conical ring, the upper limit sleeve is provided with a clearance hole that cooperates with the central column, and the step is provided with a conical surface that cooperates with the centering conical ring.

3. The loading and unloading structure of a gear hobbing machine as described in claim 1, characterized in that, The lower limiting sleeve has a through hole for the central column to pass through. The central column is slidably installed in the through hole. A limiting ring is fixed on the central column above the through hole. A second spring is sleeved on the central column between the limiting ring and the through hole. A retaining ring is fixed at the end of the central column below the through hole.

4. The loading and unloading structure of a gear hobbing machine as described in claim 1, characterized in that, The feeding assembly includes a feeding conveyor with a baffle plate and a discharge port at the end of the feeding conveyor. The discharge port is located directly above the feeding station. After the feeding conveyor transports the workpiece to the discharge port, the workpiece falls into the centering unit through the discharge port and is placed on three positioning claws.

5. The loading and unloading structure of a gear hobbing machine as described in claim 1, characterized in that, A material ejector ring concentric with the rotary table is fixed on the frame. The material ejector ring has teeth and clearance grooves. A gear and a limiting frame are fixed on the support rod. At least two limiting wheels are rotatably mounted on the limiting frame. When the positioning component is in the loading or processing position, the corresponding limiting wheel abuts against the surface of the material ejector ring and restricts the rotation of the support rod. When the positioning component is in the unloading position, the gear meshes with the teeth, and the limiting wheel disengages from the material ejector ring under the action of the clearance groove.

6. The loading and unloading structure of a gear hobbing machine as described in claim 1, characterized in that, The receiving assembly includes a receiving conveyor. A receiving section is provided at one end of the receiving conveyor directly below the unloading station. The receiving section includes a baffle and a slider slidably mounted on the baffle. A roller frame is hinged to the slider, and multiple rollers are rotatably mounted on the roller frame. Multiple elastic elements are provided on the baffle for elastically supporting the slider and the roller frame. When the workpiece falls onto the roller, the roller frame rotates around the slider and compresses the elastic elements downward, conveying the workpiece onto the receiving conveyor.

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