Bending device for PTC thermistor pin

Abstract

The application relates to a PTC thermistor pin bending device, which comprises a bending device body, an arc-shaped pressing plate is arranged on one side of an upper pressing plate of the bending device body, facing a lower pressing plate of the bending device body, the arc-shaped pressing plate is connected with the upper pressing plate through at least one elastic piece, and the inner arc surface shape of the arc-shaped pressing plate is matched with the outer contour shape of a PTC thermistor body; a positioning groove is arranged on one side of the lower pressing plate, facing the upper pressing plate, the shape of the positioning groove is matched with the shape of the PTC thermistor body, and the position of the positioning groove is arranged opposite to the inner arc surface of the arc-shaped pressing plate, so that when the upper pressing plate and the lower pressing plate relatively move, the arc-shaped pressing plate can press and fix the PTC thermistor body arranged in the positioning groove. Through the synergistic effect of the components, the problem that the fixing of the thermistor is not firm and influences the bending precision when the existing bending device bends the pin of the thermistor is effectively solved.

Description

Technical Field

[0001] This application relates to the technical field of thermistor manufacturing, and in particular to a bending device for the pins of a PTC thermistor. Background Technology

[0002] Positive temperature coefficient (PTC) thermistors, due to their resistance increasing significantly with temperature, are widely used in critical electronic circuits such as overcurrent protection, temperature sensing, and motor starting. PTC thermistors are typically made of barium titanate-based semiconductor ceramic materials. Their brittleness and weak shear resistance make the lead bending process a critical point for quality control during production. The consistency of the lead bending angle and the positional accuracy directly determine the assembly reliability and electrical performance stability of the device on the PCB.

[0003] Chinese patent application CN202323036233.0 discloses a bending device for PTC thermistor leads, comprising a support frame, with a first fixed plate and a second fixed plate fixed at the two ends of the upper longitudinal position of the support frame, a driven roller shaft mounted above the first fixed plate, and a drive roller shaft mounted above the second fixed plate. A drive motor is provided on one side of the drive roller shaft, and a conveyor belt connects the drive roller shaft and the driven roller shaft. A fixed frame is provided at the upper end of the support frame, and a first telescopic cylinder is installed at the top of the fixed frame. An upper pressure plate is fixedly connected below the first telescopic cylinder. Several sets of identical mounting grooves are arranged longitudinally on both sides of the upper pressure plate, and bending pressure blocks are installed in the mounting grooves. Second telescopic cylinders are provided at both ends of the inner side of the fixed frame, and a lower pressure plate is fixedly connected to the upper end of the second telescopic cylinder. Several sets of identical bending grooves are arranged longitudinally on both sides of the lower pressure plate.

[0004] The aforementioned technologies have the following drawbacks: the rigid clamping method of the upper and lower plates on the bending equipment can easily lead to stress concentration on the surface of the PTC thermistor, causing it to crack. Furthermore, since the conveyor belt only separates the resistor body through spacing grooves, the radial force generated when the bending block presses down can easily push the PTC thermistor body to slide or deflect within the grooves, causing the lead bending point to deviate from the designed position and affecting the bending accuracy of the PTC thermistor leads. Utility Model Content

[0005] To address the problem of insecure thermistor fixing affecting bending accuracy when bending the leads of existing bending equipment, this application provides a bending device for PTC thermistor leads.

[0006] The bending device for PTC thermistor leads provided in this application adopts the following technical solution: A bending device for the pins of a PTC thermistor includes a bending device body. An arc-shaped pressure plate is provided on the side of the upper pressure plate of the bending device body facing the lower pressure plate of the bending device body. The arc-shaped pressure plate is connected to the upper pressure plate by at least one elastic element. The inner arc surface shape of the arc-shaped pressure plate is adapted to the outer contour shape of the PTC thermistor body. The lower pressure plate has a positioning groove on the side facing the upper pressure plate. The shape of the positioning groove matches the shape of the PTC thermistor body, and its position is directly opposite to the inner arc surface of the arc-shaped pressure plate. This allows the arc-shaped pressure plate to press and fix the PTC thermistor body placed in the positioning groove when the upper and lower pressure plates move relative to each other.

[0007] Furthermore, the elastic element is a spring, one end of which is fixedly connected to the upper pressure plate, and the other end is fixedly connected to the arc-shaped pressure plate.

[0008] Furthermore, the number of elastic elements is two, and the two elastic elements are respectively disposed at both ends of the arc-shaped pressure plate along its length direction.

[0009] Furthermore, both ends of the arc-shaped pressure plate are fixedly connected to limiting posts extending towards the upper pressure plate, and the upper pressure plate is provided with limiting grooves that cooperate with the limiting posts; the two elastic elements are respectively sleeved on the outer periphery of the corresponding limiting posts.

[0010] Furthermore, an elastic rubber pad is bonded to the inner arc surface of the arc-shaped pressure plate.

[0011] Furthermore, the surface of the elastic rubber pad is provided with a plurality of anti-slip protrusions arranged in an array.

[0012] Furthermore, a flexible pad is adhered to the inner surface of the positioning groove.

[0013] In summary, the beneficial technical effects of this application are as follows: 1. By using the contour design of the arc-shaped pressure plate and the positioning groove of the lower pressure plate, combined with the "bidirectional limiting" structure, the PTC thermistor body is accurately and stably fixed; the guide mechanism formed by the limiting post and the limiting groove further constrains the movement trajectory of the arc-shaped pressure plate, effectively preventing the displacement or rotation of the resistor body during the bending process, thereby ensuring the accuracy of the pin bending angle and position. 2. The elastic rubber pad and the flexible pad with the positioning groove form an "upper-lower" double-sided buffer system, which absorbs impact energy and compensates for processing tolerances, avoiding local stress concentration caused by rigid contact; the high coefficient of friction of the rubber pad and the "mechanical interlocking" effect of the anti-slip protrusions enhance static friction and disperse shear stress, preventing sliding damage, and reducing the risk of micro-damage to the brittle PTC thermistor body while ensuring stable positioning. 3. The elastic rubber pad and the flexible pad in the positioning groove can compensate for the minor manufacturing tolerances of PTC thermistor bodies of different specifications or batches, enhancing the equipment's adaptability to product differences. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the overall structure of an embodiment of this application; Figure 2 yes Figure 1 A magnified view of part A in the middle; Figure 3 This is a schematic diagram of the structure of the upper pressure plate and the arc-shaped pressure plate in an embodiment of this application.

[0015] Explanation of reference numerals in the attached figures: 1. The bending equipment body; 2. Upper pressure plate; 21. Elastic element; 22. Arc-shaped pressure plate; 221. Limiting post; 222. Elastic rubber pad; 23. Limiting groove; 3. Lower pressure plate; 31. Positioning groove; 311. Flexible pad. Detailed Implementation

[0016] The technical solutions of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0017] This application discloses a device for bending the leads of a PTC thermistor. (Refer to...) Figure 1 and Figure 2 It includes a bending equipment body 1, an arc-shaped pressure plate 22 is provided on the side of the upper pressure plate 2 of the bending equipment body 1 facing the lower pressure plate 3 of the bending equipment body 1, the arc-shaped pressure plate 22 is connected to the upper pressure plate 2 by at least one elastic element 21, and the inner arc surface shape of the arc-shaped pressure plate 22 is adapted to the outer contour shape of the PTC thermistor body.

[0018] The lower pressure plate 3 has a positioning groove 31 on the side facing the upper pressure plate 2. The shape of the positioning groove 31 matches the shape of the PTC thermistor body, and its position is directly opposite to the inner arc surface of the arc-shaped pressure plate 22. This allows the arc-shaped pressure plate 22 to press and fix the PTC thermistor body placed in the positioning groove 31 when the upper pressure plate 2 and the lower pressure plate 3 move relative to each other.

[0019] Thus, when the upper pressure plate 2 and the lower pressure plate 3 move relative to each other, the arc-shaped pressure plate 22 first contacts the thermistor body in the positioning groove 31, and the elastic element 21 generates an initial clamping force to achieve preliminary fixation. As the upper pressure plate 2 and the lower pressure plate 3 continue to move relative to each other, the elastic element 21 is further compressed, and the arc-shaped pressure plate 22 and the positioning groove 31 together form a "bidirectional limiting" structure. The arc-shaped pressure plate 22 applies vertical pressure from the top, and the positioning groove 31 provides reaction force support from the bottom. The two work together to firmly clamp the PTC thermistor body in three-dimensional space, effectively preventing displacement or rotation during bending. At the same time, the bending pressure block set on the upper pressure plate 2 and the bending groove at the corresponding position on the lower pressure plate 3 work together to precisely bend the pins while the thermistor body is stably fixed. This bending equipment solves the problem of easy displacement and damage of PTC thermistors during lead bending by combining structural conformal design, elastic buffering, and bidirectional positioning. It effectively improves the problem of thermistors not being firmly fixed and affecting bending accuracy when bending the leads of existing bending equipment.

[0020] Specifically, refer to Figure 1 and Figure 3 The elastic element 21 is a spring, one end of which is fixedly connected to the upper pressure plate 2, and the other end is fixedly connected to the arc-shaped pressure plate 22. To achieve a stable connection, both ends of the spring can be rigidly connected to the upper pressure plate 2 and the arc-shaped pressure plate 22 through welding, threaded connection, or snap-fit ​​structure, thus forming a rigid transmission chain of "upper pressure plate 2 - spring - arc-shaped pressure plate 22". In this way, the contour design of the arc-shaped pressure plate 22 and the positioning groove 31 ensures that the PTC thermistor body is in a precise geometric constraint state when pressed. The elastic buffering characteristics provided by the spring element effectively compensate for the problem of incomplete contact of the contour structure caused by manufacturing tolerances. The two work together to achieve a dual protection mechanism of "rigid positioning" and "elastic buffering". It ensures extremely high positioning accuracy through contour design, and effectively avoids micro-damage to the brittle PTC thermistor body caused by pure rigid pressing through elastic buffering, thereby significantly improving the product yield while ensuring bending accuracy.

[0021] Furthermore, referring to Figure 1 and Figure 3There are two elastic elements 21, which are respectively located at both ends of the arc-shaped pressure plate 22 along its length. The two symmetrically arranged springs together form a "double-pivot" support structure. When the upper pressure plate 2 moves downward and applies pressure, the pressure is transmitted synchronously and evenly to the arc-shaped pressure plate 22 through the springs at both ends, causing the arc-shaped pressure plate 22 to produce uniform elastic deformation along its length. This deformation mode ensures that the inner arc surface of the arc-shaped pressure plate 22 can achieve complete and stable surface contact with the outer contour of the PTC thermistor body, thereby significantly improving the uniformity and stability of the clamping. More importantly, the symmetrical arrangement of the springs at both ends forms an anti-torsional moment on both sides of the arc-shaped pressure plate 22, which can effectively prevent the PTC thermistor body from undergoing slight rotation or displacement during bending, thereby ensuring the accuracy of the pin bending angle and position.

[0022] Furthermore, referring to Figure 1 and Figure 3 Both ends of the arc-shaped pressure plate 22 are fixedly connected to limiting posts 221 extending upwards in the direction of the pressure plate 2. The upper pressure plate 2 is provided with limiting grooves 23 that cooperate with the limiting posts 221. Two elastic elements 21 are respectively sleeved on the outer periphery of the corresponding limiting posts 221.

[0023] When the upper pressure plate 2 is pressed down, the limiting posts 221 at both ends of the arc-shaped pressure plate 22 insert into and slide vertically along the corresponding limiting grooves 23 on the upper pressure plate 2, thus forming a "post-groove" sliding pair. This sliding pair can forcibly constrain the movement trajectory of the arc-shaped pressure plate 22 to strictly maintain the vertical direction, completely eliminating any horizontal deviation or rotational tendency that occurs during the pressing process, thereby ensuring that the direction of the pressing force is completely coincident with the axis of the PTC thermistor body, providing a key guiding guarantee for the core positioning accuracy. Moreover, when the pressing force increases abnormally, the ends of the limiting posts 221 will make rigid contact with the bottom of the limiting grooves 23, thus forming a mechanical hard limit. This structure can effectively prevent the spring from being over-compressed, avoiding damage to the arc-shaped pressure plate 22, the elastic element 21, or the PTC thermistor body itself due to excessive pressing force, significantly improving the safety and reliability of the equipment.

[0024] Furthermore, two elastic elements 21 are symmetrically arranged at both ends of the arc-shaped pressure plate 22, and together with the precision guiding constraint formed by the limiting post 221 and the limiting groove 23, they form a symmetrical mechanical system of "double springs and double limits". This system can automatically balance the clamping force at both ends of the arc-shaped pressure plate 22 during the clamping process, effectively eliminating the risk of unilateral overpressure or underpressure caused by processing errors or assembly gaps, ensuring that the pressure on all parts of the PTC thermistor body is uniform, and further improving the stability of the bending operation and the consistency of the finished product.

[0025] Furthermore, referring to Figure 1 and Figure 3An elastic rubber pad 222 is bonded to the inner arc surface of the arc-shaped pressure plate 22. This rubber pad serves as a flexible interlayer between the rigid arc-shaped pressure plate 22 and the PTC thermistor body. Preferably, the thickness of the elastic rubber pad 222 can be selected from 0.5mm to 5mm, and its material can be selected from materials with suitable elasticity, wear resistance, and high coefficient of friction, such as nitrile rubber, silicone rubber, or neoprene rubber.

[0026] When the curved pressure plate 22 presses down and contacts the PTC thermistor body, the elastic rubber pad 222 effectively absorbs the impact energy, transforming the instantaneous rigid collision into a flexible elastic buffer. This avoids localized stress concentration caused by rigid contact between the curved pressure plate 22 and the resistor body, significantly reducing the risk of damage to the PTC thermistor body, especially its brittle ceramic material, due to impact during the initial pressing stage. Furthermore, the elastic rubber pad 222 undergoes compressive deformation under pressure, effectively compensating for minor dimensional deviations between the contoured surface of the curved pressure plate 22 and the actual contour of the PTC thermistor body (e.g., due to manufacturing tolerances or slight differences between different batches of resistor bodies). The rubber pad achieves "self-adaptive fit" through its elastic filling properties, ensuring complete contact of the pressing surface even with minor gaps between the inner curved surface of the curved pressure plate 22 and the contour of the resistor body, thereby improving the equipment's versatility and pressing reliability for different specifications or batches of PTC thermistors.

[0027] Furthermore, the elastic rubber pad 222 has a high coefficient of friction. When pressed against the surface of the PTC thermistor body, it significantly enhances the static friction between the arc-shaped pressure plate 22 and the resistor body. This characteristic helps prevent minor displacement or rotation of the resistor body due to equipment vibration or inertia generated by bending force during lead bending. Moreover, at the moment of lead bending, the bending force generates impact vibration and is transmitted through the arc-shaped pressure plate 22. The elastic rubber pad 222, with its damping characteristics, can absorb and attenuate this high-frequency vibration energy. This helps maintain a continuous and stable clamping force, preventing micro-damage or slight positioning misalignment of the PTC thermistor body caused by vibration, and ensuring the smoothness and consistency of the bending process.

[0028] At the same time, refer to Figure 1 and Figure 3 The elastic rubber pad 222 has multiple arrayed anti-slip protrusions (not shown in the figure) on its surface facing the PTC thermistor body. These anti-slip protrusions together form a microtextured structure. Preferably, the anti-slip protrusions can be hemispherical, pyramidal, cylindrical, or other regular geometric shapes, and their height can be selected in the range of 0.1 mm to 0.5 mm. The spacing between adjacent protrusions can be optimized according to the required coefficient of friction.

[0029] The micro-textured structure of the anti-slip protrusions significantly increases the actual contact area between the rubber pad and the surface of the PTC thermistor. Compared to an absolutely smooth contact surface, this structure greatly enhances the static friction between the two through the "mechanical interlocking" effect formed by the protrusions and the micro-unevenness of the resistor body surface. Furthermore, at the moment of lead bending, the bending force generates shear stress, which is transmitted to the rubber pad through the arc-shaped pressure plate 22. The arrayed anti-slip protrusions create a "multi-point anchoring" effect. This effect effectively disperses the concentrated shear force acting on the resistor body into multiple tiny force vectors, thereby avoiding the tendency to slip due to excessive stress concentration at a single point. This mechanical dispersion mechanism ensures that even under high-speed bending conditions, the PTC thermistor body maintains extremely high positioning stability, effectively preventing positioning failure caused by single-point slippage.

[0030] Additionally, refer to Figure 1 and Figure 2 A flexible pad 311 is bonded to the inner surface of the positioning groove 31. This flexible pad 311 serves as a secondary buffer layer for the positioning groove 31, and together with the elastic rubber pad 222 disposed on the inner arc surface of the arc-shaped pressure plate 22, it forms an "upper-lower" double-sided flexible buffer system.

[0031] When the upper pressure plate 2 and the lower pressure plate 3 move relative to each other, the flexible pads 311 and elastic rubber pads 222 located on the upper and lower sides of the resistor body work together. The flexible pads 311 absorb the impact energy generated during the pressing process through their own elastic deformation, and cooperate with the upper rubber pad to achieve bidirectional attenuation of the clamping force. This mechanism effectively avoids rigid contact between the arc-shaped pressure plate 22 and the positioning groove 31 and the PTC thermistor body, significantly reducing the risk of damage to the brittle resistor body due to local stress concentration.

[0032] Unless otherwise defined, the technical or scientific terms used in this application shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms "first," "second," "third," and similar terms used in this application specification and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. The terms "an" or "a" and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms "comprising" or "including" and similar terms mean that the elements or objects preceding "comprising" or "including" encompass the elements or objects listed following "comprising" or "including" and their equivalents, and do not exclude other elements or objects. "Above," "below," "left," "right," etc., are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0033] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A bending device for the pins of a PTC thermistor, comprising a bending device body (1), characterized in that, An arc-shaped pressure plate (22) is provided on the side of the upper pressure plate (2) of the bending equipment body (1) facing the lower pressure plate (3) of the bending equipment body (1). The arc-shaped pressure plate (22) is connected to the upper pressure plate (2) by at least one elastic element (21). The inner arc surface shape of the arc-shaped pressure plate (22) is adapted to the outer contour shape of the PTC thermistor body. The lower pressure plate (3) has a positioning groove (31) on the side facing the upper pressure plate (2). The shape of the positioning groove (31) matches the shape of the PTC thermistor body, and its position is directly opposite to the inner arc surface of the arc-shaped pressure plate (22). This allows the arc-shaped pressure plate (22) to press and fix the PTC thermistor body placed in the positioning groove (31) when the upper pressure plate (2) and the lower pressure plate (3) move relative to each other.

2. The bending device for PTC thermistor leads according to claim 1, characterized in that, The elastic element (21) is a spring, one end of which is fixedly connected to the upper pressure plate (2), and the other end is fixedly connected to the arc-shaped pressure plate (22).

3. The bending device for PTC thermistor leads according to claim 2, characterized in that, The number of elastic elements (21) is two, and the two elastic elements (21) are respectively disposed at both ends of the arc-shaped pressure plate (22) along its length direction.

4. The bending device for PTC thermistor leads according to claim 3, characterized in that, Both ends of the arc-shaped pressure plate (22) are fixedly connected to limiting posts (221) extending toward the upper pressure plate (2), and the upper pressure plate (2) is provided with limiting grooves (23) that cooperate with the limiting posts (221); the two elastic elements (21) are respectively sleeved on the outer periphery of the corresponding limiting posts (221).

5. The bending device for PTC thermistor leads according to claim 1, characterized in that, An elastic rubber pad (222) is bonded to the inner arc surface of the arc-shaped pressure plate (22).

6. The bending device for PTC thermistor leads according to claim 5, characterized in that, The surface of the elastic rubber pad (222) is provided with a plurality of anti-slip protrusions arranged in an array.

7. The bending device for PTC thermistor leads according to claim 1, characterized in that, A flexible pad (311) is bonded to the inner surface of the positioning groove (31).

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