Shaft workpiece machining clamp of CNC (computer numerical control) lathe

Abstract

The invention relates to the technical field of machine tool clamps, in particular to a CNC numerical control lathe shaft workpiece machining clamp which comprises a three-jaw chuck, the three-jaw chuck comprises a chuck body, a large bevel gear, a small bevel gear, clamping jaws and an auxiliary clamping device, a shaft part is clamped in the radial direction through the three-jaw chuck, basic clamping force is kept, and meanwhile the clamping jaws are clamped through the clamping jaws. An auxiliary clamping device is additionally arranged inside to further stabilize the clamping effect, along with rotation of the three-jaw chuck, a centrifugal block in the auxiliary clamping device moves along a set path under the action of centrifugal force, an internal transmission assembly is driven to operate accordingly, the transmission assembly guides an auxiliary bevel gear to generate the rotation trend tending to tighten a small bevel gear, and the clamping effect is further stabilized. Furthermore, a locking effect is exerted on the large bevel gear through the small bevel gear, so that the whole structure forms a linkage locking effect, and the problem that when an existing three-jaw chuck is subjected to low-speed or variable-speed machining, a shaft piece is prone to loosening is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of machine tool fixtures, and particularly to a fixture for machining shaft workpieces on a CNC lathe. Background Art

[0002] With the rapid development of numerical control machining technology, CNC lathes are widely used in the field of mechanical manufacturing, especially in occasions where high-precision and high-efficiency machining of shaft workpieces is required. In order to achieve rapid positioning and stable clamping of workpieces, three-jaw chucks are generally used as the mainstream clamping devices in the prior art.

[0003] However, three-jaw chucks have obvious limitations in practical applications. During the high-speed rotary machining of shaft workpieces, due to the centrifugal force generated by high-speed rotation, the moving parts (such as sliders and jaws) on the three-jaw chuck will be interfered by the centrifugal force, thus affecting the clamping force on the workpiece. As the spindle speed increases, the instability of this clamping force becomes more obvious, which is very likely to cause dangerous accidents such as loosening, yawing or flying out of the workpiece during the machining process, not only affecting the machining accuracy and efficiency, but also posing a great safety hazard.

[0004] In the prior art, for example, the Chinese utility model patent (authorization publication number CN203887252U) discloses a self-clamping three-jaw chuck, which includes a housing, a clamping mechanism, a rubber fixing sleeve, and rubber fixing sleeve screws. The clamping mechanism is fixed inside the housing, and the clamping mechanism is composed of a chuck clamping jaw pressure plate, a chuck clamping jaw pressure plate screw, a lever, a lever shaft, a return spring, a centrifugal steel ball, a chuck clamping jaw, and a lever shaft locking nut.

[0005] The clamping force of this three-jaw chuck completely depends on the centrifugal action of the centrifugal steel balls. At the moment when the lathe starts or rotates at a low speed (such as in the working condition of reducing speed for heavy cutting), insufficient centrifugal force may cause the clamping force to decrease, and it is difficult to ensure the stability of the workpiece only by the interference fit of the rubber fixing sleeve. Summary of the Invention

[0006] Aiming at the problems existing in the prior art, a fixture for machining shaft workpieces on a CNC lathe is provided. The shaft part is clamped radially by a three-jaw chuck. While maintaining the basic clamping force, an auxiliary clamp is added inside to further stabilize the clamping effect. As the three-jaw chuck rotates, the centrifugal blocks in the auxiliary clamp move along a predetermined path under the action of centrifugal force, and thereby drive the internal transmission components to operate. The transmission components then guide the auxiliary bevel gear to generate a rotational tendency to tighten the small bevel gear, and further apply a locking action to the large bevel gear through the small bevel gear, so that the overall structure forms a linkage locking effect, solving the problem that the existing three-jaw chuck is prone to cause loosening of the shaft part during low-speed or variable-speed machining.

[0007] To solve the problems of the prior art, the present invention provides a machining fixture for shaft workpieces of a CNC lathe, including a three-jaw chuck. The three-jaw chuck includes a chuck body, a large bevel gear, a small bevel gear, a jaw, and an auxiliary clamping device. The auxiliary clamping device includes: an auxiliary bevel gear rotatably disposed in the chuck body, coaxially arranged with the large bevel gear, and meshing with at least one of the small bevel gears; a centrifugal block slidably disposed in the chuck body along the radial direction of the chuck body, and the centrifugal block can generate a centrifugal displacement with the rotation of the chuck body; a transmission assembly disposed in the chuck body and connecting the centrifugal block and the auxiliary bevel gear, for converting the radial displacement of the centrifugal block into the rotational movement of the auxiliary bevel gear; when the rotational speed of the chuck body exceeds a set threshold, the centrifugal block slides in a direction away from the axis of the chuck body, and through the transmission assembly, guides the auxiliary bevel gear to generate a rotational tendency to tighten the small bevel gear, and then applies a locking effect on the large bevel gear through the small bevel gear.

[0008] Preferably, the transmission assembly includes a trigger ring slidably disposed in the chuck body along the axial direction of the chuck body. The trigger ring has an inclined surface that contacts the centrifugal block. When the centrifugal block moves away from the axis of the chuck body, the trigger ring moves along its axial direction; an execution ring coaxially connected to the auxiliary bevel gear, and an arc-shaped groove is provided on the inner circumferential surface of the execution ring; a guiding pin disposed on the trigger ring along the radial direction of the trigger ring, and one end of the guiding pin extends into the arc-shaped groove and is slidably engaged with it.

[0009] Preferably, a positioning port is provided in the chuck body. The execution ring has: a connecting cylinder rotatably disposed coaxially in the positioning port, and the arc-shaped groove is circumferentially distributed on the inner circumferential surface of the connecting cylinder; a connecting ring coaxially connected to the connecting cylinder and the auxiliary bevel gear.

[0010] Preferably, an installation cavity close to the positioning port is further provided in the chuck body. The trigger ring has: a passive ring rotatably disposed in the installation cavity, and an inclined surface cooperating with the centrifugal block is formed on the inner circumference of the passive ring; a driving cylinder coaxially disposed at one end of the passive ring facing the positioning port, and the guiding pin is disposed on the driving cylinder.

[0011] Preferably, an elastic reset element is provided between the passive ring and the positioning port.

[0012] Preferably, connecting holes are provided on the driving cylinder along its circumferential direction, the guiding pin is slidably disposed coaxially in the connecting holes, a spring is provided between the guiding pin and the inner wall of the installation cavity, and the guiding pin abuts in the arc-shaped groove.

[0013] Preferably, the passive ring has a tapered groove coaxially with it, and the centrifugal block is slidably engaged with the tapered groove.

[0014] Preferably, inner ball bearings are arranged on the contact surface between the centrifugal block and the conical groove, and the centrifugal block is in rolling fit with the conical groove.

[0015] Preferably, outer ball bearings are arranged between the outer circumferential surface of the passive ring and the inner wall of the installation cavity, and the passive ring is in rolling fit with the installation cavity.

[0016] Preferably, mounting grooves are arranged in the chuck body in a circumferential distribution thereof, and the mounting grooves extend along the radial direction of the chuck body.

[0017] The beneficial effects of the present application compared with the prior art are as follows: In the present application, a three-jaw chuck is used to clamp the shaft part radially. While maintaining the basic clamping force, an auxiliary clamp is added inside to further stabilize the clamping effect. As the three-jaw chuck rotates, the centrifugal block in the auxiliary clamp moves along a predetermined path under the action of centrifugal force, and thereby drives the internal transmission component to operate. The transmission component then guides the auxiliary bevel gear to generate a rotational tendency to tighten the small bevel gear, and further applies a locking effect to the large bevel gear through the small bevel gear, so that the overall structure forms a linkage locking effect. In this process, the problem that the clamping force of the chuck jaws may decrease due to the centrifugal force is effectively alleviated, the clamping stability and working reliability are enhanced, and the higher requirements for maintaining the clamping force under high-speed rotation conditions are met. The entire system has a compact structure and a clear transmission path, effectively converting the centrifugal phenomenon caused by rotation into a driving force for increasing the clamping force, realizing the dynamic coupling of the clamping and self-locking functions, helping to improve the machining accuracy and operation safety, and at the same time solving the problem that the existing three-jaw chuck is prone to loosen the shaft part during low-speed or variable-speed machining. Description of the Drawings

[0018] Figure 1 is a perspective view of a fixture for machining shaft parts on a CNC lathe according to the present invention.

[0019] Figure 2 is a perspective sectional view of a fixture for machining shaft parts on a CNC lathe according to the present invention.

[0020] Figure 3 is a sectional view of a fixture for machining shaft parts on a CNC lathe according to the present invention.

[0021] Figure 4 is Figure 3 a partial enlarged view of part A of

[0022] Figure 5 is a schematic diagram of the installation of the centrifugal block in the chuck body of a fixture for machining shaft parts on a CNC lathe according to the present invention.

[0023] Figure 6It is a perspective view of the internal structure in a CNC lathe shaft workpiece machining fixture of the present invention from the first perspective.

[0024] Figure 7 It is Figure 6 a partial enlarged view of part B.

[0025] Figure 8 It is Figure 6 a partial enlarged view of part C.

[0026] Figure 9 It is Figure 6 a partial enlarged view of part D.

[0027] Figure 10 It is a perspective view of the internal structure in a CNC lathe shaft workpiece machining fixture of the present invention from the second perspective.

[0028] The reference numerals in the figure are: 11, chuck body; 111, positioning port; 112, mounting groove; 12, large bevel gear; 13, small bevel gear; 14, jaw; 21, auxiliary bevel gear; 22, centrifugal block; 23, transmission assembly; 231, trigger ring; 2311, passive ring; 23 .12, tapered groove; 2313, drive cylinder; 2314, connection hole; 232, execution ring; 2321, arc groove; 2322, connection cylinder; 2323, connection ring; 233, guide pin; 234, elastic reset element; 235, spring; 24, inner ball; 25, outer ball. Detailed implementation manners

[0029] To further understand the features, technical means, specific purposes and functions achieved by the present invention, the present invention will be further described in detail below in conjunction with the drawings and specific implementation manners.

[0030] As Figure 1 , Figure 2 and Figure 3As shown in the figure, a fixture for machining shaft workpieces on a CNC lathe includes a three-jaw chuck. The three-jaw chuck includes a chuck body 11, a large bevel gear 12, a small bevel gear 13, and a jaw 14. It also includes an auxiliary clamping device, which includes: an auxiliary bevel gear 21 rotatably arranged in the chuck body 11, coaxially arranged with the large bevel gear 12, and meshing with at least one of the small bevel gears 13; a centrifugal block 22 slidably arranged in the chuck body 11 along the radial direction of the chuck body 11, and the centrifugal block 22 can generate a centrifugal displacement with the rotation of the chuck body 11; a transmission component 23 arranged in the chuck body 11 and connecting the centrifugal block 22 and the auxiliary bevel gear 21, for converting the radial displacement of the centrifugal block 22 into the rotational motion of the auxiliary bevel gear 21; when the rotational speed of the chuck body 11 exceeds a set threshold, the centrifugal block 22 slides in a direction away from the axis of the chuck body 11, and through the transmission component 23, guides the auxiliary bevel gear 21 to generate a rotational tendency to tighten the small bevel gear 13, and then exerts a locking effect on the large bevel gear 12 through the small bevel gear 13.

[0031] The three-jaw chuck moves three equally-spaced jaws 14 simultaneously towards the center along the radial direction to clamp the shaft workpiece. Its structure drives the three jaws in linkage through an internal large bevel gear 12 to make them move synchronously. When operating the chuck wrench or the CNC system drives the chuck body 11 to rotate the spiral disk on the large bevel gear 12, the jaws 14 move along the radial direction in the guide rail to firmly clamp the shaft workpiece in the central position.

[0032] The auxiliary clamping device constitutes a dynamic self-locking mechanism inside the three-jaw chuck. Inside the chuck body 11, the auxiliary bevel gear 21 is installed in a rotatable manner, and its axis is coaxial with the large bevel gear 12, thus forming a stable transmission foundation in terms of structure. The auxiliary bevel gear 21 meshes with at least one small bevel gear 13 to ensure that an effective driving force can be exerted on the small bevel gear 13 during its rotation. The small bevel gear 13 forms a locking linkage with the large bevel gear 12 through the meshing relationship, thereby indirectly acting on the clamping stability of the three-jaw chuck.

[0033] The centrifugal block 22 is slidably arranged in the chuck body 11 and can move freely along the radial direction. When the chuck rotates, it is affected by the centrifugal force and generates a displacement behavior along the radial direction outwards. This centrifugal displacement is not only a direct response to the change in the rotation speed of the chuck, but also the driving source for subsequent auxiliary clamping actions. A transmission component 23 is also arranged inside the chuck body 11 for converting the radial displacement of the centrifugal block 22 into the rotational motion of the auxiliary bevel gear 21.

[0034] When the chuck body 11 reaches or exceeds the set rotational speed threshold, the centrifugal force acting on the centrifugal block 22 causes it to slide rapidly in a direction away from the axis of the chuck body 11. This sliding behavior is converted by the transmission assembly 23 into a rotational tendency of the auxiliary bevel gear 21, which develops towards the meshing direction of the small bevel gear 13, driving the small bevel gear 13 to rotate. As the small bevel gear 13 continues to rotate, a locking relationship is formed between it and the large bevel gear 12, thereby placing the entire clamping system in a state of passively enhancing the clamping force. The secondary clamping force automatically applied as the rotational speed increases effectively suppresses the problem of the main clamping force decreasing due to centrifugal force.

[0035] As Figure 3 , Figure 5 , Figure 6 , Figure 7 , Figure 8 , Figure 9 and Figure 10 As shown, the transmission assembly 23 includes a trigger ring 231 slidably disposed axially within the chuck body 11 along the axial direction of the chuck body 11. The trigger ring 231 has an inclined surface that contacts the centrifugal block 22. When the centrifugal block 22 moves away from the axis of the chuck body 11, the trigger ring 231 moves axially along its axis; an execution ring 232 coaxially connected to the auxiliary bevel gear 21, with an arc-shaped groove 2321 provided on the inner circumferential surface of the execution ring 232; and a guide pin 233 radially disposed on the trigger ring 231, with one end of the guide pin 233 extending into the arc-shaped groove 2321 and slidingly cooperating with it.

[0036] The trigger ring 231 is arranged along the axial direction of the chuck body 11 and can perform an axial sliding movement inside the chuck. Its surface is provided with an inclined surface structure that contacts the centrifugal block 22: when the chuck rotates at high speed, the centrifugal block 22 slides radially outward due to the enhanced centrifugal force, and its outer edge then contacts the inclined surface on the trigger ring 231, thereby generating a thrust along the axial direction of the chuck, prompting the entire trigger ring 231 to displace axially.

[0037] The execution ring 232 is coaxially arranged with the auxiliary bevel gear 21 and is rigidly connected, enabling the rotation of the execution ring 232 to directly drive the auxiliary bevel gear 21 to rotate. A number of arc-shaped grooves 2321 are machined on its inner circumferential surface, and these arc-shaped grooves 2321 cooperate with the guide pin 233 to convert the axial movement of the trigger ring 231 into the rotational movement of the execution ring 232.

[0038] The guide pin 233 is fixed to the trigger ring 231 in the radial direction. One end extends and inserts into the arc-shaped groove 2321 on the inner circumferential surface of the actuator ring 232, forming a sliding fit relationship with it. As the trigger ring 231 moves axially, the guide pin 233 slides along the arc-shaped groove 2321. Due to the arc-shaped groove, this sliding not only drives the guide pin 233 to move radially, but also forces the actuator ring 232 to rotate.

[0039] The entire transmission process starts from the radial sliding of the centrifugal block 22, drives the trigger ring 231 to slide axially through the inclined plane contact, and then through the interaction between the guide pin 233 and the arc-shaped groove 2321, finally rotates the actuator ring 232, thereby driving the auxiliary bevel gear 21 to rotate, and further realizing the tightening trend of the small bevel gear 13 to complete the locking of the large bevel gear 12.

[0040] As Figure 4 shown, a positioning port 111 is provided in the chuck body 11. The actuator ring 232 has: a connecting cylinder 2322, which is coaxially rotatably arranged in the positioning port 111, and the arc-shaped groove 2321 is circumferentially distributed on the inner circumferential surface of the connecting cylinder 2322; a connecting ring 2323, which is coaxially connected to the connecting cylinder 2322 and the auxiliary bevel gear 21.

[0041] The connecting cylinder 2322 is coaxially and rotatably embedded in the positioning port 111 of the chuck body 11, which not only plays a physical constraint role on the rotation axis, but also effectively avoids vibration or meshing error caused by component offset under high-speed rotation.

[0042] A number of arc-shaped grooves 2321 are distributed on the inner circumferential surface of the connecting cylinder 2322. The arc-shaped grooves 2321 are opened circumferentially to form a curved track matching the guide pin 233. This circumferential arrangement can make full use of the axial sliding behavior of the guide pin 233 driven by the trigger ring 231 to ensure that the sliding path in the arc-shaped groove 2321 is both natural and efficient, and finally realize the stable rotation of the connecting cylinder 2322 and even the entire actuator ring 232.

[0043] The connecting ring 2323 is integrally and coaxially connected to the connecting cylinder 2322 in structure, and also maintains a coaxial linkage relationship with the auxiliary bevel gear 21. It can directly transmit the rotational movement of the connecting cylinder 2322 to the auxiliary bevel gear 21.

[0044] As Figure 4 and Figure 6As shown, an installation cavity is also provided in the chuck body 11 near the positioning port 111. The trigger ring 231 has: a passive ring 2311 rotatably arranged in the installation cavity, and an inclined surface cooperating with the centrifugal block 22 is formed on the inner circumference of the passive ring 2311; a driving cylinder 2313 coaxially arranged at one end of the passive ring 2311 facing the positioning port 111, and the guiding pin 233 is arranged on the driving cylinder 2313.

[0045] The internal structure of the chuck body 11 is provided with an installation cavity adjacent to the positioning port 111, which is used to accommodate and support the key trigger ring 231 in the transmission system, so that the entire centrifugal linkage mechanism has a more stable installation foundation and accurate motion guidance.

[0046] In this structure, the trigger ring 231 is composed of a passive ring 2311 and a driving cylinder 2313. The passive ring 2311 is rotatably installed in the installation cavity of the chuck body 11, and an inclined surface structure is machined on its inner peripheral surface for contact cooperation with the centrifugal block 22. When the chuck rotates at a high speed, due to the centrifugal force, the centrifugal block 22 moves radially outward, and its edge contacts the inner inclined surface of the passive ring 2311, pushing the passive ring 2311 to rotate around its axis or guiding it to generate a small amount of axial displacement. The contact between the inclined surface and the centrifugal block 22 not only establishes the initial response path of the transmission system, but also provides a continuous power source for subsequent driving actions.

[0047] A driving cylinder 2313 is arranged at the front end of the passive ring 2311, and the two are coaxially connected to jointly form the transmission unit of the trigger ring 231. The driving cylinder 2313 is located on the side close to the positioning port 111 and is connected to the execution ring 232. The guiding pin 233 is radially arranged on the driving cylinder 2313, and one end of it is inserted into the arc-shaped groove 2321 of the execution ring 232 to form a sliding fit relationship with it. As the passive ring 2311 rotates or moves under the action of the centrifugal block 22, the driving cylinder 2313 moves synchronously, thereby driving the guiding pin 233 to slide along a predetermined trajectory in the arc-shaped groove 2321. Since the arc-shaped groove 2321 is designed with a specific arc, the sliding process of the guiding pin 233 converts the axial movement into the rotation of the execution ring 232, thereby driving the auxiliary bevel gear 21 to complete the torque output in the clamping direction.

[0048] As Figure 4 and Figure 6 shown, an elastic reset element 234 is arranged between the passive ring 2311 and the positioning port 111.

[0049] During the high-speed rotation of the chuck, the centrifugal block 22 moves radially outward due to the driving force of the centrifugal force, and drives the passive ring 2311 to form an axial displacement by virtue of its contact relationship with the inner inclined surface of the passive ring 2311. However, in order for the passive ring 2311 to achieve this displacement, the elastic force exerted by the elastic reset element 234 must be overcome first, which forms a controlled response mechanism: only when the centrifugal force reaches a strength sufficient to overcome this elastic force, the axial movement will be triggered. This design effectively avoids misoperations caused by short-term disturbances or speed changes, enabling the system to have good selectivity and response thresholds before realizing the clamping action.

[0050] During the axial displacement of the passive ring 2311, it drives the driving cylinder 2313 to move integrally with it, thereby pushing the guide pin 233 installed on the driving cylinder 2313 to slide along the arc-shaped groove 2321 on the actuator ring 232, causing the actuator ring 232 to undergo an angular displacement and further driving the auxiliary bevel gear 21 to rotate, forming a driving trend for the small bevel gear 13 and completing the clamping process of the shaft part. At this time, the system is in a stable clamping state, and each component operates coordinately under the drive of external forces and structural guidance to ensure that the shaft part is firmly and reliably fixed in the three-jaw chuck.

[0051] When the three-jaw chuck stops rotating, the centrifugal force quickly disappears, and the centrifugal block 22 retracts inward without external force support and no longer exerts an axial thrust on the passive ring 2311. At this time, the previously compressed or stretched elastic reset element 234 begins to release the elastic potential energy it stores and acts on the passive ring 2311 in the reverse direction, pushing it back to the initial position. With the reset of the passive ring 2311, the driving cylinder 2313 also retracts backward, and the guide pin 233 slides in the arc-shaped groove 2321 in the reverse direction, causing the actuator ring 232 to rotate reversely. During this process, the auxiliary bevel gear 21 rotates accordingly, thereby releasing the driving trend for the small bevel gear 13, and the shaft part originally in a tightly clamped state is loosened. At this time, the operator can easily separate it from the three-jaw chuck by rotating the small bevel gear 13 to achieve fast and safe workpiece replacement.

[0052] As Figure 4 、 Figure 6 shown, connection holes 2314 are provided on the driving cylinder 2313 and are distributed along its circumferential direction. The guide pin 233 is coaxially and slidably arranged in the connection holes 2314. A spring 235 is arranged between the guide pin 233 and the inner wall of the installation cavity, and the guide pin 233 abuts in the arc-shaped groove 2321.

[0053] By providing connection holes 2314 distributed circumferentially on the driving cylinder 2313, each guiding pin 233 can be respectively installed inside it, achieving uniform driving and stable linkage of the actuating ring 232. As a force transmission component, the guiding pin 233 is designed to be coaxially and slidably arranged in the connection hole 2314, which not only ensures the guiding property of the guiding pin 233 in the radial direction but also endows it with good linear transmission effect during movement, being conducive to the precise rotation and position control of the actuating ring 232. Meanwhile, a spring 235 is provided between the guiding pin 233 and the inner wall of the installation cavity, enabling the guiding pin 233 to have a certain elastic pre-tightening force. The spring 235 can not only absorb the instantaneous impact generated during the clamping or releasing process but also stably abut the guiding pin 233 against the arc-shaped groove 2321 when the guiding pin 233 is not subjected to external force, preventing it from loosening or moving abnormally, and prolonging the structural stability and service life of the system.

[0054] As Figure 4 and Figure 6 shown, the passive ring 2311 has a conical groove 2312 coaxial with it, and the centrifugal block 22 is slidably engaged with the conical groove 2312.

[0055] The passive ring 2311 has a conical groove 2312 coaxially arranged with it. The conical groove 2312 can not only guide the radial movement of the centrifugal block 22 but also form an effective component force in the axial direction, thereby pushing the passive ring 2311 to form an axial displacement.

[0056] When the three-jaw chuck rotates at high speed, the centrifugal block 22 moves from the inside to the outside under the action of centrifugal force. Its outer contour comes into contact with the inner wall of the conical groove 2312 and slides along the conical surface. This sliding engagement converts the radial movement of the centrifugal block 22 into an axial thrust acting on the passive ring 2311, forming the initial driving force for the clamping action.

[0057] The sliding between the centrifugal block 22 and the conical groove 2312 not only brings the coherence and self-adaptability of the structural response but also makes the generation of the clamping force closely coupled with the rotational speed.

[0058] The sliding engagement method also facilitates the rapid return of the centrifugal block 22 when the chuck stops rotating. When the rotation stops and the centrifugal force is released, the centrifugal block 22 slides back to its original position along the conical groove 2312 under its own weight or the action of the elastic member, preparing for the subsequent clamping cycle.

[0059] As Figure 4 shown, inner balls 24 are provided on the contact surface between the centrifugal block 22 and the conical groove 2312, and the centrifugal block 22 is in rolling engagement with the conical groove 2312.

[0060] By setting inner ball bearings 24 between the contact surfaces of the centrifugal blocks 22 and the conical grooves 2312, the original sliding fit is optimized into a rolling fit. The rolling fit has a lower friction coefficient compared to the sliding fit, which can effectively reduce energy loss, reduce wear of the mating surfaces, extend the service life of key components, and is especially suitable for complex working conditions with frequent start-stop and high rotational speeds.

[0061] The inner ball bearings 24 are usually embedded in the contact surfaces of the centrifugal blocks 22. When the three-jaw chuck starts to rotate and gradually accelerates, the centrifugal blocks 22 move from the inside out under the action of centrifugal force, and their outer contours form line contact or point contact with the inner walls of the conical grooves 2312 through the inner ball bearings 24, thus achieving low-resistance rolling motion.

[0062] As Figure 4 shown, outer ball bearings 25 are provided between the outer circumferential surface of the passive ring 2311 and the inner wall of the installation cavity, and the passive ring 2311 is in rolling fit with the installation cavity.

[0063] Outer ball bearings 25 are provided between the outer circumferential surface of the passive ring 2311 and the inner wall of the installation cavity, enabling the passive ring 2311 to be in rolling fit with the installation cavity. This structural design greatly reduces the frictional resistance of the passive ring 2311 during axial movement, enabling it to respond more smoothly and quickly to the thrust from the centrifugal mechanism or other drive structures.

[0064] When the small bevel gear 13 rotates, it can drive the auxiliary bevel gear 21 to rotate, and the auxiliary bevel gear 21 can drive the trigger ring 231 and the actuator ring 232 to rotate in the chuck body 11, thus avoiding affecting the rotation of the small bevel gear 13.

[0065] As Figure 4 and Figure 10 shown, mounting grooves 112 are provided in the chuck body 11 and are distributed along its circumferential direction, and the mounting grooves 112 extend radially along the chuck body 11.

[0066] The chuck body 11 is provided with mounting grooves 112 that are evenly distributed along its circumferential direction, and each mounting groove 112 extends in the radial direction of the chuck body 11. This structural design not only helps to enhance the structural symmetry and load balance of the chuck body 11, but also provides a clear mounting reference and movement guide for the arrangement of internal functional components. By installing the centrifugal blocks 22 in the mounting grooves 112, a clear guiding path is provided for them when they are radially stressed or moving, avoiding offset or jamming phenomena.

[0067] The above embodiments merely represent one or several implementation manners of the present invention. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the protection scope of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all fall within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the appended claims.

Claims

1. A machining fixture for shaft workpieces of a CNC lathe, comprising a three-jaw chuck. The three-jaw chuck includes a chuck body, a large bevel gear, a small bevel gear and a jaw, and is characterized in that, It further includes an auxiliary clamp, and the auxiliary clamp includes: An auxiliary bevel gear rotatably arranged in the chuck body, coaxially arranged with the large bevel gear, and meshed with at least one of the small bevel gears; A centrifugal block slidably arranged in the chuck body along the radial direction of the chuck body, and the centrifugal block can generate a centrifugal displacement with the rotation of the chuck body; A transmission assembly arranged in the chuck body and connecting the centrifugal block and the auxiliary bevel gear, for converting the radial displacement of the centrifugal block into the rotational movement of the auxiliary bevel gear; When the rotational speed of the chuck body exceeds a set threshold, the centrifugal block slides in a direction away from the axis of the chuck body, and through the transmission assembly, guides the auxiliary bevel gear to generate a rotational tendency to tighten the small bevel gear, and then applies a locking effect on the large bevel gear through the small bevel gear.

2. The machining fixture for shaft workpieces of a CNC lathe according to claim 1, characterized in that, The transmission assembly includes A trigger ring slidably arranged in the chuck body along the axial direction of the chuck body, and the trigger ring has an inclined surface in contact with the centrifugal block. When the centrifugal block is away from the axis of the chuck body, the trigger ring moves along its axial direction; An execution ring coaxially connected with the auxiliary bevel gear, and an arc-shaped groove is arranged on the inner circumferential surface of the execution ring; A guiding pin arranged on the trigger ring along the radial direction of the trigger ring, and one end of the guiding pin extends into the arc-shaped groove and is in sliding fit with it.

3. The machining fixture for shaft workpieces of a CNC lathe according to claim 2, characterized in that, A positioning port is arranged in the chuck body, and the execution ring has A connecting cylinder rotatably arranged coaxially in the positioning port, and the arc-shaped groove is distributed circumferentially on the inner circumferential surface of the connecting cylinder; A connecting ring coaxially connected with the connecting cylinder and the auxiliary bevel gear.

4. A machining fixture for shaft workpieces of a CNC lathe according to claim 3, characterized in that, An installation cavity close to the positioning port is also arranged in the chuck body, and the trigger ring has A passive ring rotatably arranged in the installation cavity, and an inclined surface matching the centrifugal block is formed on the inner circumference of the passive ring; A driving cylinder coaxially arranged at one end of the passive ring facing the positioning port, and the guiding pin is arranged on the driving cylinder.

5. A machining fixture for shaft workpieces of a CNC lathe according to claim 4, characterized in that, An elastic reset element is arranged between the passive ring and the positioning port.

6. A machining fixture for shaft workpieces of a CNC lathe according to claim 4, characterized in that, Connecting holes distributed along the circumferential direction of the driving cylinder are arranged on the driving cylinder, the guiding pin is coaxially slidably arranged in the connecting holes, a spring is arranged between the guiding pin and the inner wall of the installation cavity, and the guiding pin abuts in the arc-shaped groove.

7. A machining fixture for shaft workpieces of a CNC lathe according to any one of claims 4-6, characterized in that, The passive ring has a conical groove coaxially with it, and the centrifugal block is in sliding fit with the conical groove.

8. A machining fixture for shaft workpieces of a CNC lathe according to claim 7, characterized in that Inner balls are arranged on the contact surface between the centrifugal block and the conical groove, and the centrifugal block is in rolling fit with the conical groove.

9. The machining fixture for shaft workpieces of a CNC lathe according to claim 7, characterized in that, Outer balls are arranged between the outer circumferential surface of the passive ring and the inner wall of the installation cavity, and the passive ring is in rolling fit with the installation cavity.

10. A machining fixture for shaft workpieces of a CNC lathe according to any one of claims 1-6, characterized in that, Installation grooves distributed along the circumferential direction of the chuck body are arranged in the chuck body, and the installation grooves extend along the radial direction of the chuck body.

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