A positioning tool for fast clamping gear

Abstract

This utility model relates to the field of machining technology, specifically disclosing a positioning fixture for quickly clamping gears. The positioning fixture includes a positioning shaft and an inner pull rod. One end of the positioning shaft is configured to fit a central hole and is connected to the inner pull rod; the other end of the positioning shaft is used to connect to a gear. The inner pull rod is disposed in a guide hole of the positioning shaft and is detachably connected to the inner pull rod. When the inner pull rod moves away from the tailstock, the end of the positioning shaft tightens and securely connects to the gear. When the inner pull rod returns to its original position, the end of the positioning shaft retracts, allowing the gear to disengage from the positioning shaft. This solves the problem in the prior art where existing fixtures cannot efficiently and stably clamp gears, resulting in low production efficiency and poor quality stability of precision gears.

Description

Technical Field

[0001] This utility model relates to the field of machining technology, specifically to a positioning fixture for quick clamping of gears. Background Technology

[0002] In the field of precision machinery manufacturing, especially in equipment involving high-precision transmission, the machining quality of precision gears plays a crucial role. Specifically, the machining accuracy of the gear teeth directly affects the gear's transmission efficiency, noise level, and service life. Therefore, precision machining of gears to ensure their tooth surface accuracy is a key step in the machining process.

[0003] In the precision gear finishing process, it is usually necessary to perform gear hobbing on the tooth surface using the gear's inner bore as a reference. This is because using the gear's inner bore as a positioning reference can better ensure key accuracy indicators such as coaxiality during gear machining. Currently, the clamping methods commonly used in the industry for secondary gear hobbing finishing are as follows:

[0004] First, the heat-treated gear blank is mounted onto the positioning shaft. Since the gear blank may deform after heat treatment, its position needs precise adjustment to ensure the accuracy of the subsequent gear hobbing process. Specifically, the operator manually uses a dial indicator to measure and adjust the gear's outer diameter runout until it is controlled within 0.01mm. After adjustment, the machine tool is started to perform a second gear hobbing operation to achieve the required precision machining accuracy.

[0005] However, this clamping method presents numerous problems in actual production: From a time cost perspective, the entire clamping process, including installing the gear blank onto the positioning shaft and manually adjusting the outer diameter runout, takes more than 2 minutes. In mass production, this undoubtedly increases the total production time and reduces efficiency. From a human resources perspective, this clamping method requires highly skilled operators. Manually adjusting the outer diameter runout requires experienced operators with proficient techniques to accurately and quickly control the runout within the specified range. This not only increases reliance on skilled workers, leading to wasted human resources, but also, due to the limited number of skilled workers, can easily cause production delays due to insufficient manpower during heavy production periods. Furthermore, this clamping method severely impacts the production rhythm, creating a bottleneck in the production process. The excessively long clamping time and reliance on skilled workers prevent subsequent processes such as gear hobbing from being performed continuously and efficiently, limiting the overall production line capacity, putting immense pressure on production, and making it difficult to meet the demands of large-scale, high-efficiency production.

[0006] In summary, the existing precision gear clamping method, which relies on manual adjustment, has significant shortcomings in terms of time consumption, human resource utilization, and production rhythm. It is necessary to optimize and improve the current tooling fixtures to enable them to fix gears in a more efficient and stable manner, thereby improving the production efficiency and quality stability of precision gear machining and solving the existing technical problems. Utility Model Content

[0007] The purpose of this invention is to provide a positioning fixture for quick gear clamping, so as to solve the problem that the existing fixtures and jigs cannot clamp gears efficiently and stably, resulting in low production efficiency and poor quality stability of precision gears.

[0008] This utility model is achieved through the following technical solution:

[0009] A positioning fixture for quick clamping of gears is used in a machine tool. One end of the machine tool is provided with a spindle and the other end is provided with a tailstock. An inner pull shaft is provided in the central hole of the spindle, and the inner pull shaft can move along the axial direction of the central hole.

[0010] The positioning fixture includes a positioning shaft and an inner pull rod. One end of the positioning shaft is configured to fit the central hole and is connected to the inner pull rod. The other end of the positioning shaft is used to connect a gear. The inner pull rod is provided in the guide hole of the positioning shaft and is detachably connected to the inner pull rod. When the inner pull rod moves away from the tailstock, the end of the positioning shaft is tightened and securely connected to the gear. When the inner pull rod is reset, the end of the positioning shaft retracts so that the gear can disengage from the positioning shaft.

[0011] Alternatively, the end of the positioning shaft is provided with a plurality of strip grooves, which are evenly spaced along the circumferential direction of the positioning shaft; wherein the extending direction of the strip grooves is parallel to the axial direction of the positioning shaft.

[0012] Alternatively, the number of the strips may be greater than or equal to 6.

[0013] Alternatively, the end of the guide hole is provided as a V-shaped hole, and the large-diameter end of the V-shaped hole faces the tail top; the end of the inner pull rod is formed as a tapered portion adapted to the V-shaped hole; when the inner pull rod moves toward the main shaft, the tapered portion presses against the inner wall surface of the V-shaped hole and causes the positioning shaft to tighten.

[0014] Alternatively, the taper of both the V-shaped hole and the tapered portion is 25° to 40°.

[0015] Alternatively, the taper of the inner tie rod may be greater than the taper of the positioning shaft.

[0016] Alternatively, the positioning shaft body and the inner hole of the gear are clearance-fitted, and the clearance between the two is less than or equal to 0.02 mm.

[0017] Alternatively, the inner tie rod is connected to the inner tie shaft via a coupling sleeve.

[0018] Alternatively, the coupling sleeve is connected to the inner tie rod and the inner tie shaft respectively via a threaded connection structure.

[0019] Alternatively, the material of the positioning shaft is 9CrSi.

[0020] Compared with the prior art, this utility model has the following advantages and beneficial effects:

[0021] Through the above technical solution, based on the structure of this positioning fixture, the automatic tensioning and contraction of the end of the positioning shaft can be achieved through the linkage of the inner pull shaft and the inner pull rod. The entire clamping process requires no manual adjustment; only the insertion and disengagement of the gears need to be completed, shortening the clamping time for a single gear. In mass production, this reduces the total clamping time, prevents machine tools from being idle while waiting for clamping, effectively improves the pace of the production line, and breaks through the bottleneck process formed by traditional clamping methods. Since the clamping process of the positioning fixture is fully automated by the mechanical structure, operators only need to perform simple gear placement and removal operations, and no professional skills training is required to start working. This not only reduces the demand for skilled workers and lowers human resource costs, but also avoids fluctuations in processing accuracy caused by differences in manual operation, ensuring the consistency of batch products.

[0022] In addition, one end of the positioning shaft is adapted to the center hole of the main shaft and connected to the inner pull shaft to ensure the coaxiality of the positioning shaft and the main shaft; the other end is driven to tighten via the inner pull rod, so that the inner hole of the gear and the positioning shaft fit tightly together, achieving precise positioning and avoiding the problem of inconsistent reference in traditional clamping. The positioning fixture is mainly composed of the positioning shaft and the inner pull rod, with a simple structure that is easy to manufacture and maintain; the inner pull rod and the inner pull shaft are detachably connected, which makes it easy to replace the inner pull rod or the end structure of the positioning shaft with a suitable one according to the inner hole size of different gear specifications.

[0023] The inner pull shaft drives the inner pull rod through axial force, causing the positioning shaft to tighten. The gear and positioning shaft have surface contact, achieving a tight fit. This effectively prevents gear loosening due to vibration or stress during machining, reduces shape errors in tooth surface machining (such as tooth profile and tooth direction deviations), and further improves the gear's transmission performance. This solves the problems of low efficiency, reliance on manual labor, and unstable accuracy associated with traditional clamping methods, providing reliable tooling support for efficient and high-quality machining of precision gears. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the exemplary embodiments of this utility model, the drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this utility model and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings:

[0025] Figure 1 A front view of the positioning fixture for quick-clamping gears provided by this utility model in one embodiment;

[0026] Figure 2 A cross-sectional view of the positioning fixture for quick-clamping gears provided by this utility model in one embodiment.

[0027] The markings and corresponding component names in the attached diagram are as follows: 11-Main shaft, 12-Tail top, 13-Center hole, 14-Inner pull shaft, 2-Gear, 3-Positioning shaft, 31-Strip groove, 32-Guide hole, 321-V-shaped hole, 4-Inner pull rod, 41-Tapered part, 5-Coupling sleeve. Detailed Implementation

[0028] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. It should be noted that while the description of these embodiments is intended to aid in understanding the present invention, it does not constitute a limitation thereof. The specific structural and functional details disclosed herein are only for describing exemplary embodiments of the present invention. However, the present invention may be embodied in many alternative forms and should not be construed as being limited to the embodiments described herein.

[0029] According to a specific embodiment of this disclosure, a positioning fixture for quickly clamping and positioning a gear 2 is provided for a machine tool. One end of the machine tool is provided with a spindle 11, and the other end with a tailstock 12. Figure 1 and Figure 2 Specific embodiments thereof are shown.

[0030] See Figure 1 and Figure 2As shown, an inner pull shaft 14 is provided in the central hole 13 of the main shaft 11, and the inner pull shaft 14 can move along the axial direction of the central hole 13. The positioning fixture includes a positioning shaft body 3 and an inner pull rod 4. One end of the positioning shaft body 3 is formed to fit the central hole 13 and is connected to the inner pull shaft 14; the other end of the positioning shaft body 3 is used to connect the gear 2; the guide hole 32 of the positioning shaft body 3 is provided with the inner pull rod 4, and the inner pull rod 4 is detachably connected to the inner pull shaft 14; when the inner pull shaft 14 drives the inner pull rod 4 to move away from the tail tip 12, the end of the positioning shaft body 3 is tightened and securely connected to the gear 2; when the inner pull shaft 14 drives the inner pull rod 4 to reset, the end of the positioning shaft body 3 retracts so that the gear 2 can disengage from the positioning shaft body 3.

[0031] During machine tool operation, the positioning fixture for the quick-clamping and positioning gear 2 achieves rapid clamping and disassembly of gear 2 through the coordinated action of various components. The specific working process is as follows: First, the gear 2 blank (after heat treatment) to be processed is aligned with one end of the positioning shaft 3 used to connect gear 2, so that the inner hole of the gear and the end of the positioning shaft 3 form a preliminary fit. At this time, the inner tie rod 4 is in the initial position, the end of the positioning shaft 3 is not tensioned, and gear 2 can be easily inserted relative to the positioning shaft 3.

[0032] After the machine tool is started, the inner pull shaft 14 inside the center hole 13 of the spindle 11 moves away from the tailstock 12 along the axis of the center hole 13 (i.e., moves inward towards the spindle 11). Since the inner pull rod 4 is detachably connected to the inner pull shaft 14, the inner pull shaft 14 drives the inner pull rod 4 to move synchronously through the connecting structure. When the inner pull rod 4 moves in the guide hole 32 of the positioning shaft 3, its special structure (such as a conical surface fit or a sloped surface drive structure) generates a radial expansion force on the end of the positioning shaft 3, causing the end of the positioning shaft 3 used to connect the gear 2 to undergo elastic deformation and tightening, thereby tightly fitting with the inner hole of the gear and achieving a tight connection of the gear 2. In this process, no manual adjustment is required. Based on the tightening fit between the inner hole of the gear and the positioning shaft 3, positioning is automatically achieved, ensuring that the axis of the gear 2 coincides with the axis of the spindle 11, and ensuring the consistency of the reference for subsequent machining.

[0033] After gear 2 is tightened, the spindle 11 drives the positioning shaft 3 and gear 2 to rotate synchronously. The tailstock 12 cooperates to achieve axial positioning, and the hobbing cutter performs secondary hobbing finishing on the tooth surface according to the preset program. Since the connection between the positioning shaft 3 and gear 2 is stable, and the positioning accuracy is guaranteed by the tooling structure itself, gear 2 will not experience radial runout exceeding the tolerance during the machining process.

[0034] After machining, the inner pull shaft 14 moves towards the tail tip 12 along the axis of the center hole 13 (i.e., resets), and the inner pull rod 4 moves synchronously in the opposite direction with the inner pull shaft 14, releasing the radial expansion force on the end of the positioning shaft 3. The end of the positioning shaft 3 contracts under its own elasticity, creating a gap between it and the inner hole of the gear. At this time, the gear 2 can be easily disengaged from the positioning shaft 3, completing one machining cycle.

[0035] Through the above technical solution, based on the structure of this positioning fixture, the automatic tensioning and contraction of the end of the positioning shaft 3 can be achieved through the linkage of the inner pull shaft 14 and the inner pull rod 4. The entire clamping process requires no manual adjustment; only the insertion and removal of gear 2 needs to be completed, shortening the clamping time of a single gear 2. In mass production, the total clamping time can be reduced, avoiding machine tool idleness due to waiting for clamping, effectively improving the pace of the production line, and breaking through the bottleneck process formed by traditional clamping methods. Since the clamping process of the positioning fixture is fully automated by the mechanical structure, operators only need to perform simple gear 2 placement and removal operations, and can start working without professional skills training. This not only reduces the demand for skilled workers and lowers human resource costs, but also avoids fluctuations in processing accuracy caused by differences in manual operation, ensuring the consistency of batch products.

[0036] In addition, one end of the positioning shaft 3 is adapted to the center hole 13 of the main shaft 11 and connected to the inner pull shaft 14 to ensure the coaxiality of the positioning shaft 3 and the main shaft 11; the other end is driven to tighten by the inner pull rod 4, so that the inner hole of the gear and the positioning shaft 3 fit tightly, achieving precise positioning and avoiding the problem of inconsistent reference in traditional clamping. The positioning fixture is mainly composed of the positioning shaft 3 and the inner pull rod 4. It has a simple structure and is easy to manufacture and maintain. The inner pull rod 4 and the inner pull shaft 14 are detachably connected, which makes it easy to replace the appropriate inner pull rod 4 or the end structure of the positioning shaft 3 according to the size of different specifications of gears 2.

[0037] The inner pull shaft 14 drives the inner pull rod 4 through axial force to tighten the positioning shaft 3. The gear 2 and the positioning shaft 3 have surface contact, achieving a tight fit. This effectively prevents the gear 2 from loosening due to vibration or force during machining, reduces shape errors in tooth surface machining (such as tooth profile and tooth direction deviations), and further improves the transmission performance of the gear 2. Thus, it solves the problems of low efficiency, reliance on manual labor, and unstable accuracy of traditional clamping methods, providing a reliable tooling guarantee for the efficient and high-quality machining of the precision gear 2.

[0038] It should be noted that the directional terms used, such as "inner" and "outer," refer to the "inner" and "outer" relative to the outline of the component, facing the component (which can be combined with...). Figure 1The direction of understanding is "inside," and vice versa. Furthermore, it should be noted that the terms used, such as "first" and "second," are used to distinguish one element from another and do not indicate sequence or importance. Moreover, in the following descriptions with accompanying drawings, the same reference numerals in different drawings represent the same element.

[0039] Specifically, the end of the positioning shaft 3 is provided with a plurality of strip grooves 31, which are evenly spaced along the circumferential direction of the positioning shaft 3; wherein, the extension direction of the strip grooves 31 is parallel to the axial direction of the positioning shaft 3.

[0040] The strip groove 31 divides the end of the positioning shaft 3 into multiple independent elastic flaps. When the inner tie rod 4 moves under the action of axial force, the flaps can generate uniform elastic expansion or contraction in the radial direction, so that the end of the positioning shaft 3 can achieve the required radial tension under a small axial driving force, reducing the driving load of the inner tie shaft 14 and the inner tie rod 4, while avoiding the risk of fixture cracking caused by rigid deformation, and extending the service life of the tooling.

[0041] The strip grooves 31 are evenly spaced along the circumference, ensuring that the size and stiffness of each elastic flap are consistent. When the inner tie rod 4 applies a radial expansion force, each flap can open outward synchronously, so that the tensioning force on the gear inner hole is evenly distributed along the circumference. The extension direction of the strip grooves 31, parallel to the axis, strictly limits the deformation direction of the elastic flaps to the radial direction, avoiding axial displacement during tensioning. At the same time, the presence of the strip grooves 31 provides a clear deformation guide for the flaps, ensuring that the deformation trajectory is consistent each time tensioning, and improving the repeatability of clamping.

[0042] Furthermore, the number of strip grooves 31 is greater than or equal to 6. The number of strip grooves 31 directly determines the number of elastic lobes (number of grooves = number of lobes). When the number is ≥ 6, the number of elastic lobes increases and the width of each lobe decreases, the radial force is distributed to more contact points, and the pressure per unit area is reduced by more than 30%, which can effectively avoid damage to the workpiece surface and reduce micro-deformation of the workpiece caused by uneven force. Thus, multiple elastic lobes form multi-point constraints, offsetting the rigidity deviation of a single lobe.

[0043] In one embodiment provided in this disclosure, the end of the guide hole 32 is provided as a V-shaped hole 321, and the large diameter end of the V-shaped hole 321 faces the tail 12; the end of the inner pull rod 4 is formed as a tapered portion 41 adapted to the V-shaped hole 321; when the inner pull rod 4 moves toward the main shaft 11, the tapered portion 41 presses against the inner wall surface of the V-shaped hole 321 and causes the positioning shaft 3 to tighten.

[0044] The V-shaped hole 321 and the tapered portion 41 are a surface-contact fitting structure. When the inner tie rod 4 moves toward the main shaft 11, the outer tapered surface of the tapered portion 41 fits tightly with the inner tapered surface of the V-shaped hole 321, automatically correcting their relative positions and ensuring that the axis of the inner tie rod 4 coincides with the axis of the positioning shaft 3. This self-centering characteristic effectively eliminates eccentricity errors caused by assembly clearances, ensuring that the axis of the gear 2 and the axis of the main shaft 11 remain highly consistent when the positioning shaft 3 is tightened, reducing tooth surface machining errors caused by reference offset.

[0045] The V-shaped hole 321 and the inclined surface of the tapered portion 41 provide a guiding function. When the inner tie rod 4 moves axially, the tapered portion 41 can smoothly slide along the tapered surface of the V-shaped hole 321, avoiding jamming or sticking. This smooth motion characteristic allows the tensioning and contraction of the positioning shaft 3 to respond quickly, reducing the ineffective time during clamping and further shortening the clamping cycle of a single gear 2. At the same time, the surface contact force distribution can disperse stress, avoiding wear on the end of the positioning shaft 3 or the inner tie rod 4 caused by local stress concentration, which helps to extend the service life of the tooling and reduce the maintenance frequency.

[0046] Furthermore, the taper of both the V-shaped hole 321 and the tapered portion 41 is 25° to 40°. This allows for the conversion of a stable radial tension force under the axial driving force of a conventional machine tool. This ensures a tight fit between the gear's inner hole and the positioning shaft 3, meeting vibration resistance requirements during machining, while preventing excessive radial force from causing plastic deformation of the gear's inner hole or elastic failure of the positioning shaft 3. This balances clamping stability and workpiece protection. Combined with the high-precision machining of the V-shaped hole 321 and the tapered portion 41, it effectively counteracts minor runouts during clamping, ensuring the coaxiality of the gear 2 axis and the spindle 11 axis, and improving positioning accuracy. Thus, while ensuring efficient clamping, the positioning fixture also stably guarantees the precision and reliability of gear 2 machining.

[0047] Furthermore, the taper of the inner tie rod 4 is greater than that of the positioning shaft 3. When the inner tie rod 4 moves toward the main shaft 11, due to its larger taper, the contact between its tapered portion 41 and the V-shaped hole 321 of the positioning shaft 3 gradually expands from a localized area near the small-diameter end of the V-shaped hole 321 toward the large-diameter end, forming a gradual contact process from point to surface. This contact method allows the radial tension force to act first on the inner side of the elastic flap at the end of the positioning shaft 3, and then gradually transfer to the outer side, avoiding local stress concentration caused by instantaneous full contact when both tapers are the same.

[0048] When the taper of the inner tie rod 4 is greater than that of the locating shaft 3, a slight corrective effect occurs during their contact process. In the initial tensioning stage, a slight offset at the contact point generates a lateral force due to the taper difference, pushing the elastic flap of the locating shaft 3 to automatically adjust slightly towards the axial direction until their axes coincide. This self-centering effect effectively compensates for minor coaxiality errors during the assembly of the locating shaft 3 and the inner tie rod 4, resulting in a higher degree of overlap between the locating reference of the gear inner hole and the axis of the main shaft 11. This improves the consistency of batch processing accuracy and reduces tooth surface machining errors caused by reference offset.

[0049] In one embodiment provided in this disclosure, the positioning shaft 3 and the inner hole of the gear are clearance-fitted, and the gap between them is less than or equal to 0.02 mm. This clearance fit design allows the gear 2 to easily fit into the end of the positioning shaft 3 without requiring manual alignment or hammering. The ≤0.02 mm gap ensures that the gear 2 will not wobble significantly after being fitted, requiring only a light manual push for initial positioning, reducing initial installation time and laying an efficient foundation for subsequent automated tightening. When the inner tie rod 4 drives the positioning shaft 3 to tighten, only a radial deformation of ≤0.02 mm through the elastic flap is needed to eliminate the gap and achieve tightening, eliminating the need for additional correction deformation due to excessive initial gap, and ensuring uniform fit between the inner hole of the gear and the positioning shaft 3 after tightening.

[0050] In one embodiment provided in this disclosure, the inner tie rod 4 is connected to the inner tie shaft 14 via a coupling sleeve 5. The coupling sleeve 5, as an intermediate connecting member, allows the axial driving force of the inner tie shaft 14 to be uniformly transmitted to the inner tie rod 4 along the axial direction, avoiding additional radial force caused by eccentricity. Stable axial transmission prevents force fluctuations on the elastic flap at the end of the positioning shaft 3 during tensioning, ensuring the consistency of the radial runout accuracy of the gear 2.

[0051] In actual machining, for gears 2 with different modules or different inner hole sizes, it is necessary to replace the inner tie rod 4 with one of the corresponding specifications (such as tapered parts 41 with different tapers and lengths). The coupling sleeve 5 adopts a detachable connection structure (such as key connection or threaded connection), so that the replacement of the inner tie rod 4 does not require disassembling the inner tie shaft 14. It is only necessary to loosen the fastening parts of the coupling sleeve 5 (such as the lock nut) to complete the disassembly and assembly of the inner tie rod 4. In this way, the adaptability of the positioning fixture to the machining of various types of gears 2 can be enhanced, meeting different production needs.

[0052] Furthermore, the coupling sleeve 5 is connected to the inner pull rod 4 and the inner pull shaft 14 respectively via a threaded connection structure. The threaded connection, through the mechanical self-locking characteristic of the helical pair, forms a rigid connection structure. When the coupling sleeve 5 is screwed onto the inner pull rod 4 and the inner pull shaft 14 respectively, the tight fit between the threads transmits axial force and torque, ensuring that the driving force of the inner pull shaft 14 is fully transmitted to the inner pull rod 4 without significant force loss. Compared to pin connections and snap-fit ​​connections, threaded connections have a stronger load-bearing capacity and can withstand the instantaneous impact force during the tensioning of the positioning fixture, avoiding insufficient tension or positioning misalignment due to loose connection. Simultaneously, by controlling the thread accuracy and engagement length, the coaxiality error of the connection can be guaranteed, ensuring the straightness of the axial movement of the inner pull rod 4, further improving the stability of the tensioning action of the positioning shaft 3.

[0053] Based on the detachable nature of threaded connections, when it is necessary to replace the inner tie rod 4 (e.g., to adapt to gears 2 of different specifications) or repair the coupling sleeve 5, simply rotating the coupling sleeve 5 is sufficient to separate the inner tie rod 4 from the inner tie shaft 14, shortening the replacement time for individual components. Compared to keyed connections which require hammering for disassembly and welded connections which cannot be repeatedly disassembled and reassembled, threaded connections improve the maintenance efficiency of positioning fixtures and reduce production losses caused by equipment downtime. At the same time, threaded connections offer good repeatability, maintaining connection accuracy even after multiple disassemblies and reassemblies, avoiding increased clearance due to frequent replacements, and ensuring the long-term stability of the fixture.

[0054] In one embodiment provided in this disclosure, the positioning shaft 3 is made of 9CrSi. 9CrSi is a typical alloy tool steel; after quenching and low-temperature tempering, its hardness can stably reach HRC58-62, and its surface wear resistance is superior to ordinary structural steel. Because 9CrSi contains alloying elements such as chromium (Cr) and silicon (Si), its hardenability is superior to carbon tool steel, resulting in better wear resistance and impact resistance. The positioning shaft 3 made of 9CrSi has good toughness, allowing it to open and tighten the gear 2 under pressure, and return to its original position after the pressure disappears, thus easily disengaging the gear 2. This allows the positioning shaft 3 to withstand high-frequency tooling stresses, adapt to complex working conditions on the production line, and ensure both performance and service life.

[0055] The above specific embodiments further illustrate the purpose, technical solution and beneficial effects of this utility model. It should be understood that the above are only specific embodiments of this utility model and are not intended to limit the scope of protection of this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.

Claims

1. A positioning fixture for quickly clamping gears, used in a machine tool, wherein one end of the machine tool is provided with a spindle and the other end with a tailstock, characterized in that... An inner pull shaft is provided in the central hole of the main shaft, and the inner pull shaft can move along the axial direction of the central hole; The positioning fixture includes a positioning shaft and an inner pull rod. One end of the positioning shaft is configured to fit the central hole and is connected to the inner pull rod. The other end of the positioning shaft is used to connect a gear. The inner pull rod is provided in the guide hole of the positioning shaft and is detachably connected to the inner pull rod. When the inner pull rod moves away from the tailstock, the end of the positioning shaft is tightened and securely connected to the gear. When the inner pull rod is reset, the end of the positioning shaft retracts so that the gear can disengage from the positioning shaft.

2. The positioning fixture for quick-clamping gears according to claim 1, characterized in that, The end of the positioning shaft is provided with multiple strip grooves, which are evenly spaced along the circumference of the positioning shaft; wherein the extending direction of the strip grooves is parallel to the axial direction of the positioning shaft.

3. The positioning fixture for quick-clamping gears according to claim 2, characterized in that, The number of the strip grooves is greater than or equal to 6.

4. The positioning fixture for quick-clamping gears according to claim 1, characterized in that, The end of the guide hole is provided with a V-shaped hole, and the large diameter end of the V-shaped hole faces the tail top; the end of the inner pull rod is formed into a tapered part that matches the V-shaped hole; when the inner pull rod moves toward the main shaft, the tapered part presses against the inner wall surface of the V-shaped hole and causes the positioning shaft to tighten.

5. The positioning fixture for quick-clamping gears according to claim 4, characterized in that, The taper of both the V-shaped hole and the tapered part is 25° to 40°.

6. The positioning fixture for quick-clamping gears according to claim 5, characterized in that, The taper of the inner tie rod is greater than the taper of the positioning shaft.

7. The positioning fixture for quick-clamping gears according to claim 1, characterized in that, The positioning shaft is clearance-fitted with the inner hole of the gear, and the clearance between the two is less than or equal to 0.02 mm.

8. The positioning fixture for quick-clamping gears according to claim 1, characterized in that, The inner tie rod is connected to the inner tie shaft via a coupling sleeve.

9. The positioning fixture for quick-clamping gears according to claim 8, characterized in that, The coupling sleeve is connected to the inner tie rod and the inner tie shaft respectively via a threaded connection structure.

10. The positioning fixture for quick-clamping gears according to claim 1, characterized in that, The material of the positioning shaft is 9CrSi.

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