A worm gear self-locking clamping device and its usage method

Abstract

This invention relates to a worm gear self-locking clamping device and its usage method. It includes: a housing, a rotating shaft, a worm, a worm wheel, a central shaft, a rotating disk, clamping jaws, and a limiting block; the axes of the worm wheel, the central shaft, and the rotating disk are aligned in a straight line, and the worm, the worm wheel, the central shaft, and the rotating disk are all located inside the housing; the clamping jaws, constrained by the oblique guide groove on the end face of the rotating disk and the radial guide groove on the end face of the housing, achieve synchronous centering clamping. This invention provides a worm gear self-locking clamping device that utilizes the reverse self-locking characteristic of the worm gear to maintain stable clamping even after power is removed, without the need for continuous power supply. This invention has a compact structure, is easy to operate, and has advantages such as reliable self-locking, vibration resistance, and energy saving, making it suitable for harsh working conditions such as high vibration and power outage safety.

Description

Technical Field

[0001] This invention relates to a clamping device, specifically to a worm gear self-locking clamping device and its method of use. Background Technology

[0002] In fields such as industrial automation and precision machining, extremely high requirements are placed on the clamping and fixing of workpieces or functional modules, especially in conditions involving high vibration, alternating temperatures, long-term clamping, and power failure safety protection. Clamping devices not only need to provide stable and reliable clamping force but also must possess self-locking capabilities to resist external disturbances and prevent loosening. In precision machine tool fixtures and operating devices, clamping systems often face extreme conditions such as vibration and impact, high-speed rotation, slight dimensional changes in the clamped workpiece due to thermal expansion and contraction, and interruption of drive power. The clamping mechanism must reliably maintain its clamping state even after the loss of external power input to prevent safety accidents and functional failures caused by slippage or loosening. These scenarios are often accompanied by alternating high and low temperatures, corrosive media, and strong electromagnetic interference, posing a severe challenge to the reliability of the electronic control drive unit and sensor feedback system. Clamping devices must be freed from dependence on continuous power supply or complex control loops, relying on pure mechanical transmission and mechanical self-locking principles to achieve inherent safety.

[0003] Traditional clamping solutions exhibit significant limitations when addressing these stringent requirements. For instance, while hydraulic or pneumatic clamping can provide substantial initial clamping force, its pressure maintenance relies on hydraulic valves, seals, and continuously operating oil pumps, resulting in high system energy consumption. Wear of hydraulic components can lead to internal leakage and pressure decay. Furthermore, clamping force is immediately lost upon power failure or pipeline rupture, failing to meet the "fail-safe" redundancy requirement. Electromagnetic clamping devices lose clamping force instantly upon power failure, and drawbacks such as coil heating, residual magnetic interference, and ineffectiveness with non-magnetic materials limit their application. While conventional bolt or eccentric wheel mechanical clamping methods possess a certain degree of self-locking tendency, their locking state depends on the operator's pre-tightening torque control, making it impossible to quantitatively output clamping force. Moreover, under strong vibration environments, microscopic slippage of threads or wedge surfaces can easily lead to pre-tightening force decay and loosening, requiring frequent manual inspection and re-tightening, resulting in high maintenance costs.

[0004] To address the shortcomings of existing clamping devices, such as poor self-locking reliability under extreme conditions, reliance on external power, and insufficient vibration resistance, this invention provides a compact, easy-to-operate, and highly self-locking worm gear self-locking clamping device. This device utilizes a rotating shaft to drive a worm gear, which in turn rotates a rotating disk with oblique guide grooves. Through the decoupling effect of the interactive guide grooves, the circumferential rotation of the rotating disk is uniquely decomposed into precise centripetal or centrifugal linear motion of the guide rod along the radial guide groove of the housing, ultimately driving the clamping jaws to achieve synchronous centering and clamping. The core advantage of this transmission chain lies in the inherent reverse stroke self-locking mechanical characteristics of the worm gear pair. After the drive input is removed, the worm's helix angle is less than the equivalent friction angle, achieving purely mechanical irreversible self-locking, preventing clamping force from attenuating due to vibration or impact, and maintaining stable clamping force. This invention completely eliminates the continuous dependence on electrical or hydraulic power, meeting the stringent reliability requirements of high-end equipment for clamping devices: "zero power retention, high vibration resistance and anti-loosening, long life and maintenance-free operation." Summary of the Invention

[0005] The purpose of this invention is to provide a worm gear self-locking clamping device and its usage method that is simple to operate, highly reliable, low in energy consumption, and self-locking.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A worm gear self-locking clamping device, characterized in that it comprises: a housing, a rotating shaft, a worm, a worm wheel, a central shaft, a rotating disk, clamping claws, and a limiting block; the rotating shaft is rotatably connected to the housing, and the rotating shaft is coaxially and fixedly connected to the worm; the worm is meshed with the worm wheel, and the worm wheel is coaxially and fixedly connected to the central shaft; the central shaft is rotatably connected to the housing, the rotating disk is coaxially and fixedly connected to the central shaft, and the clamping claws are slidably connected to the rotating disk and the housing respectively; the rotating shaft, the worm, the worm wheel, the central shaft, and the rotating disk are all housed within the housing.

[0008] Furthermore, the housing is a hollow cylindrical structure, providing a relatively enclosed working space for the internal components such as the worm gear and worm wheel, ensuring stable operation of the transmission components. An input window is provided on the circumferential sidewall of the housing, which can be used to install and fix the rotating shaft, inputting power to the internal mechanism. The end face of the housing has a radial guide groove, mainly used to restrict the circumferential movement of the clamping jaws, while also enabling precise engagement and positioning. The edges of the housing are rounded, and important structures are thickened to improve the overall structural strength, better withstand the reaction forces generated during clamping, and prevent housing deformation.

[0009] Furthermore, the rotating shaft has a cylindrical structure, which is used to transmit external input power to the worm, and then to the worm wheel and other parts.

[0010] Furthermore, the central shaft is a stepped cylindrical structure composed of cylindrical segments of different diameters. Different segments can respectively perform functions such as fixing the rotating disk, fixing the worm gear, and axial positioning of parts, adapting to the installation requirements of various parts inside the housing. The middle segment of the central shaft serves as the mounting reference for the worm gear and the rotating disk, achieving circumferential fixation of both via a key connection, ensuring that the worm gear and the rotating disk rotate synchronously with the central shaft. Both ends of the shaft are equipped with dedicated bearing connection structures, which are then connected to the housing via bearings. This provides stable support for the central shaft while ensuring its rotational flexibility and reducing frictional resistance during rotation.

[0011] Furthermore, the rotating disk is a disc-shaped structure with a central through hole. This central through hole can be used to connect with the central shaft via a key, enabling synchronous rotation of the rotating disk. It is a key component connecting the central shaft and the clamping jaws. The end face of the rotating disk has several obliquely symmetrically distributed guide grooves. These guide grooves can cooperate with the driven part of the clamping jaws, converting rotation into linear motion of the clamping jaws, thereby completing the clamping action. The disk has uniform overall wall thickness and no weak structures at the edges, enabling it to withstand the reaction force generated during clamping and preventing deformation of the rotating disk from affecting clamping accuracy.

[0012] Furthermore, the clamping jaws have a U-shaped columnar structure, consisting of a clamping part, a guiding part, and a driven part from top to bottom, providing stable clamping for the workpiece. The clamping part consists of two symmetrical arc-shaped side plates, with the outer surface of the side plates contacting the surface of the workpiece being clamped, and each side plate having a triangular reinforcing rib on its inner surface. The guiding part has a square block structure that slides into the radial guide groove on the housing, providing circumferential positioning during installation and preventing the clamping jaws from rotating. The driven part has a cylindrical guide rod that engages with the oblique guide groove of the rotating disk. A circular base is connected below the driven part to achieve axial limiting of the clamping jaws. The clamping jaws have a uniform thickness and a reinforced design with reinforcing ribs on the inner side to withstand the compressive force generated during clamping.

[0013] Furthermore, the method of using this worm gear self-locking clamping device includes the following steps:

[0014] S01. Preparation before clamping: Place the workpiece to be clamped at the center of the end of the housing with the radially extending guide groove, and position the workpiece between the clamping parts of each clamping jaw;

[0015] S02. Power input and reduction transmission: Rotating the shaft installed at the input window of the housing drives the worm gear fixedly connected to the shaft to rotate; the worm gear drives the worm wheel to rotate through meshing connection, and the worm wheel drives the central shaft fixedly connected to it to rotate under the support of the bearing seat holes at both ends of the housing;

[0016] S03. Motion conversion: The central shaft drives the rotating disk, which is fixed coaxially with it, to rotate synchronously. The oblique guide grooves, which are centrally symmetrically distributed on the end face of the rotating disk, rotate accordingly. The oblique guide grooves generate a radial thrust on the driven part at the bottom of the clamping claw that is fitted inside it.

[0017] S04. Guided clamping: Under the constraint of the radial guide groove at the end of the housing, the guide portion of the clamping jaw with a rectangular cross section overcomes the rotational tendency and slides in a straight line towards the center along the radial guide groove on the housing until the clamping portion of each clamping jaw abuts against the workpiece surface to complete the clamping; during this process, the limiting block installed on the housing physically blocks the clamping jaw to limit its maximum stroke range;

[0018] S05. State self-locking: After the clamping is in place, the rotating shaft stops rotating. Relying on the reverse self-locking characteristics of the meshing pair of the worm and the worm wheel, the reaction force generated by the workpiece cannot drive the rotating shaft in the reverse through the rotating disk, thereby maintaining a stable clamping state without continuous power input.

[0019] S06. Release and Reset: After the clamping task is completed, the rotating shaft is rotated in the opposite direction. The worm gear drives the rotating disk to rotate in the opposite direction through the worm wheel and the central shaft in sequence. The oblique guide groove pulls the driven part at the bottom of the clamping jaw in the opposite direction, so that the guide part of the clamping jaw slides outward along the radial guide groove of the housing, releasing the workpiece and returning to the initial opening.

[0020] The beneficial effects of implementing the worm gear self-locking clamping device and its usage method of the present invention are as follows:

[0021] (1) This system only requires one drive mechanism to achieve clamping and loosening of the inner or outer surface of the workpiece. It has a simple structure, high integration, and uniform and controllable clamping force.

[0022] (2) The rotating shaft inputs power to the worm gear, and the rotation of the worm gear drives the worm wheel, which in turn drives the rotating disk to rotate through the coaxially fixed central shaft. The clamping jaw guide part precisely matches the radial guide groove on the housing, converting the torque into the radial displacement of the clamping jaw, ensuring stable clamping stroke and high positioning accuracy. The worm gear mechanism achieves a large clamping force and a self-locking function, ensuring that the clamping jaw does not loosen during operation and reducing the risk of workpiece falling off. At the same time, due to the self-locking function, no continuous supply of electrical or hydraulic energy is required after clamping, saving energy.

[0023] (3) The interactive design of the guide grooves of the housing and the rotating disk converts the rotational motion into radial linear motion, enabling the clamping jaws to move synchronously towards the center or centrifugally, thus achieving automatic centering and clamping of the workpiece. The clamping jaws are applicable to both the inner and outer surfaces of the workpiece and do not require replacement, thereby simplifying the operation steps. The square protruding side of the lower part of the clamping jaws cleverly cooperates with the radial guide grooves on the housing to effectively prevent the clamping jaws from deflecting, ensuring that the clamping force is evenly distributed radially, which is suitable for the rapid clamping of workpieces of various specifications. Attached Figure Description

[0024] Figure 1 This is a perspective view of a worm gear self-locking clamping device according to the present invention;

[0025] Figure 2 This is an internal structural diagram of a worm gear self-locking clamping device according to the present invention;

[0026] Figure 3 This is an exploded view of the internal parts of a worm gear self-locking clamping device according to the present invention;

[0027] Figure 4 This is a left view of the internal structure of a worm gear self-locking clamping device according to the present invention;

[0028] Figure 5 This is a three-dimensional structural diagram of the rotating disk of the worm gear self-locking clamping device of the present invention;

[0029] In the diagram: 1-shell, 2-shaft, 3-worm gear, 4-worm wheel, 5-central shaft, 6-rotating disk, 7-clamping jaw, 8-limiting block. Detailed Implementation

[0030] The following description, in conjunction with the accompanying drawings, further illustrates a worm gear self-locking clamping device and its usage method according to the present invention:

[0031] like Figure 1 , 2As shown in Figures 3, 4, and 5, this invention provides a worm gear self-locking clamping device, characterized in that it comprises: a housing 1, a rotating shaft 2, a worm 3, a worm wheel 4, a central shaft 5, a rotating disk 6, a clamping jaw 7, and a limiting block 8; the rotating shaft 2 is rotatably connected to the housing 1, and the rotating shaft 2 is coaxially and fixedly connected to the worm 3, realizing synchronous rotation of the worm 3 and the rotating shaft 2; the worm 3 is meshed with the worm wheel 4, transmitting power from the worm 3 to the worm wheel 4; the worm wheel 4 is meshed with the central shaft 5, the rotating disk 6, the clamping jaw 7, and the limiting block 8. The spindle 5 is coaxially fixedly connected, and the two rotate synchronously; the spindle 5 is rotatably connected to the housing 1, and the rotating disk 6 is coaxially fixedly connected to the spindle 5. The spindle 5, the worm gear 4, and the rotating disk 6 rotate synchronously; the clamping jaws 7 are slidably connected to the rotating disk 6 and the housing 1 respectively, so that the clamping jaws 7 can move radially; the rotating shaft 2, the worm 3, the worm gear 4, the spindle 5, and the rotating disk 6 are all housed within the housing 1.

[0032] Furthermore, the end face of the rotating disk 6 is provided with a plurality of oblique guide grooves that are centrally symmetrically distributed. The clamping claw 7 is installed in the oblique guide groove through the driven part provided at its bottom, so that the clamping claw 7 moves along the oblique guide groove without rotating.

[0033] Furthermore, the housing 1 is cylindrical, with an axially extending accommodating cavity inside, capable of holding the part within it; an input window is provided on the circumferential sidewall of the housing 1 for mounting the rotating shaft 2; bearing seat holes are provided at both ends of the housing 1 to support the central shaft 5; a plurality of radially extending guide grooves are provided at one end of the housing 1, and the clamping claw 7 is movably placed in the guide groove; the housing 1 and the rotating disk 6 together form an axial constraint and circumferential positioning of the clamping claw 7;

[0034] Furthermore, the clamping claw 7 includes a clamping part, a guiding part, and a driven part connected from top to bottom; the guiding part is a block structure with a rectangular cross-section to form a sliding fit with the radial guide groove on the housing 1; the driven part is used to extend into the oblique guide groove of the rotating disk 6 and is driven by pressure when the oblique guide groove rotates;

[0035] Furthermore, the clamping device also includes the limiting block 8 installed on the housing 1, which is used to limit the stroke of the clamping claw 7 and prevent the clamping claw 7 from disengaging from the housing 1 during operation.

[0036] like Figure 1 , 2 As shown in Figures 3, 4, and 5, the working principle of the worm gear self-locking clamping device of the present invention is as follows:

[0037] First, the workpiece to be clamped is placed at the center of the end face of the housing 1 with the radially extending guide groove. At this time, the clamping jaws 7 are in the initial relaxed state. When it is necessary to clamp the workpiece, the operator or an external drive mechanism applies clockwise rotational power to the rotating shaft 2. Since the rotating shaft 2 is coaxially and fixedly connected to the worm gear 3, the rotating shaft 2 directly drives the worm gear 3 to rotate synchronously. The worm gear 3 then transmits the rotational motion to the worm wheel 4 through meshing transmission. Furthermore, since the worm wheel 4 is coaxially and fixedly connected to the central shaft 5, the rotation of the worm wheel 4 further drives the central shaft 5 to rotate smoothly. At the same time, the central shaft 5 drives the rotating disk 6, which is coaxially fixed to it, to rotate synchronously.

[0038] The rotating disk 6 has several centrally symmetrically distributed oblique guide grooves on its end face. When the rotating disk 6 rotates clockwise, the angle of the oblique guide grooves changes relative to the housing 1, and the driven part at the bottom of the clamping claw 7, which is installed in the oblique guide groove, is pushed. Since the guide part of the clamping claw 7 slides in the radial guide groove opened on the end face of the housing 1, and the cross-section of the guide part is rectangular, the clamping claw 7 cannot rotate and can only slide in a straight line along the radial guide groove of the housing 1. As the rotating disk 6 continues to rotate, it pushes the clamping claw 7 to retract synchronously in the clamping direction until its clamping part tightly abuts against the surface of the workpiece, completing the clamping action.

[0039] Once clamped in place, external power input to the rotating shaft 2 is stopped. Because this device employs a worm gear transmission mechanism, and the helix angle of the worm is less than the friction angle, the worm wheel 4 cannot drive the worm 3 in reverse. Relying on the self-locking characteristics of the worm gear, even if the external driving force is interrupted and no additional locking mechanism is applied, the clamping jaws 7 can still reliably clamp the workpiece using the self-locking force of the transmission assembly, ensuring that the workpiece will not loosen or shift during subsequent processing and movement.

[0040] When the workpiece needs to be unloaded, power is input to the rotating shaft 2 to make it rotate counterclockwise, which in turn drives the worm gear 3, the worm wheel 4, the central shaft 5, and the rotating disk 6 to rotate in the opposite direction. At this time, the oblique guide groove on the rotating disk 6 will pull the driven part at the bottom of the clamping jaw 7 in the opposite direction, causing the guide part of the clamping jaw 7 to slide in the loosening direction along the radial guide groove of the housing 1. At this time, the clamping jaw 7 opens, releases the workpiece, and returns to the initial opening position, waiting for the next clamping operation.

[0041] The method of using the worm gear self-locking clamping device of the present invention includes the following steps:

[0042] S01. Place the workpiece to be clamped on the end face of the housing 1 on the side with the radially extending guide groove, and position the workpiece between the clamping portions of each of the clamping claws 7;

[0043] S02. Power is input to the rotating shaft 2 installed at the input window of the housing 1, which sequentially drives the rotating shaft 2, the worm 3, and the worm wheel 4 to rotate; the worm wheel 4 drives the central shaft 5, which is coaxially fixedly connected to it, to rotate under the support of the bearing seat holes at both ends of the housing 1;

[0044] S03. The central shaft 5 drives the rotating disk 6, which is fixed coaxially with it, to rotate synchronously. The oblique guide grooves distributed in a centrally symmetrical manner on the end face of the rotating disk 6 rotate accordingly. The oblique guide grooves generate a radial thrust on the driven part at the bottom of the clamping claw 7, which is fitted and installed therein.

[0045] S04. Under the constraint of the radial guide groove at the end of the housing 1, the guide portion of the clamping claw 7 with a rectangular cross section overcomes the rotation tendency and slides linearly in the clamping direction along the radial guide groove on the housing 1 until the clamping portion of each clamping claw 7 abuts against the workpiece surface, thus completing the clamping action.

[0046] S05. After clamping in place, stop inputting power to the rotating shaft 2. Relying on the self-locking characteristics of the worm gear, a stable clamping state can be maintained without continuous power input. At this time, the workpiece can be processed.

[0047] S06. After the workpiece processing task is completed, power is input to the rotating shaft 2 to make it rotate in the opposite direction, which in turn drives the worm 3, the worm wheel 4, the central shaft 5 and the rotating disk 6 to rotate in the opposite direction. The oblique guide groove pulls the driven part at the bottom of the clamping jaw 7 in the opposite direction, so that the guide part of the clamping jaw 7 slides in the relaxation direction along the radial guide groove of the housing 1, releases the workpiece and returns to the initial opening.

[0048] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A worm gear self-locking clamping device, characterized in that, include: The enclosure comprises a housing (1), a rotating shaft (2), a worm (3), a worm wheel (4), a central shaft (5), a rotating disk (6), clamping claws (7), and a limiting block (8). The rotating shaft (2) is rotatably connected to the housing (1), and the rotating shaft (2) is coaxially fixedly connected to the worm (3). The worm (3) is meshed with the worm wheel (4), and the worm wheel (4) is coaxially fixedly connected to the central shaft (5). The central shaft (5) is rotatably connected to the housing (1), and the rotating disk (6) is coaxially fixedly connected to the central shaft (5). The clamping claws (7) are slidably connected to the rotating disk (6) and the housing (1), respectively. The rotating shaft (2), the worm (3), the worm wheel (4), the central shaft (5), and the rotating disk (6) are all housed within the housing (1).

2. The worm gear self-locking clamping device as described in claim 1, characterized in that, The end face of the rotating disk (6) is provided with several oblique guide grooves that are centrally symmetrically distributed. The clamping claw (7) is installed in the oblique guide groove through the driven part provided at its bottom.

3. The worm gear self-locking clamping device as described in claim 1, characterized in that, The housing (1) is cylindrical and has an axially extending accommodating cavity inside. An input window is provided on the circumferential sidewall of the housing (1) for installing the rotating shaft (2). Bearing seat holes are provided at both ends of the housing (1) to support the central shaft (5). Several radially extending guide grooves are provided at one end of the housing (1), and the clamping claw (7) is movably placed in the guide groove. The housing (1) and the rotating disk (6) together form an axial constraint and circumferential positioning of the clamping claw (7).

4. The worm gear self-locking clamping device as described in claim 1, characterized in that, The clamping claw (7) includes a clamping part, a guiding part and a driven part connected from top to bottom; the guiding part is a block structure with a rectangular cross section to form a sliding fit with the radial guide groove on the housing (1); the driven part is used to extend into the oblique guide groove of the rotating disk (6) and is driven by pressure when the oblique guide groove rotates.

5. The worm gear self-locking clamping device as described in claim 1, characterized in that, It also includes a limiting block (8) installed on the housing (1) for limiting the stroke of the clamping claw (7).

6. A method of using the worm gear self-locking clamping device according to any one of claims 1-5, characterized in that, Includes the following steps: S01. Preparation before clamping: Place the workpiece to be clamped at the center of the end of the housing (1) on the side with the radially extending guide groove, and place the workpiece between the clamping parts of each of the clamping claws (7); S02. Power input and speed reduction transmission: Rotate the shaft (2) installed at the input window of the housing (1) to drive the worm (3) fixedly connected to the shaft (2) to rotate; the worm (3) drives the worm wheel (4) to rotate through meshing connection, and the worm wheel (4) drives the central shaft (5) fixedly connected to it to rotate under the support of the bearing seat holes at both ends of the housing (1); S03. Motion conversion: The central shaft (5) drives the rotating disk (6) fixed coaxially to rotate synchronously. The oblique guide grooves distributed in a centrally symmetrical manner on the end face of the rotating disk (6) rotate accordingly. The oblique guide grooves generate a radial thrust on the driven part at the bottom of the clamping claw (7) that is fitted inside it. S04. Guided clamping: Under the constraint of the radial guide groove at the end of the housing (1), the guide portion of the clamping claw (7) with a rectangular cross section overcomes the rotation tendency and slides in a straight line towards the center along the radial guide groove on the housing (1) until the clamping portion of each clamping claw (7) abuts against the workpiece surface to complete the clamping; during this process, the limiting block (8) installed on the housing (1) physically blocks the clamping claw (7) to limit its maximum stroke range; S05. State self-locking: After clamping in place, the rotating shaft (2) stops rotating. Relying on the reverse self-locking characteristics of the meshing pair of the worm (3) and the worm wheel (4), the reaction force generated by the workpiece cannot drive the rotating shaft (2) in the reverse through the rotating disk (6), thereby maintaining a stable clamping state without continuous power input. S06. Release and reset: After the clamping task is completed, the rotating shaft (2) is rotated in the opposite direction. The worm (3) drives the rotating disk (6) to rotate in the opposite direction through the worm wheel (4) and the central shaft (5). The oblique guide groove pulls the driven part at the bottom of the clamping claw (7) in the opposite direction, so that the guide part of the clamping claw (7) slides outward along the radial guide groove of the housing (1), releases the workpiece and returns to the initial opening.

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