High-stability laminated NTC (Negative Temperature Coefficient) thermistor

Abstract

The invention relates to the technical field of thermistors, in particular to a high-stability laminated NTC thermistor which comprises ceramic resistor discs, inner electrode plates and a frame assembly, the frame assembly is made of ceramic materials, the ceramic resistor discs are installed in the frame assembly, and the inner electrode plates are installed in the frame assembly. Corresponding inner electrode plates are arranged on the ceramic resistor discs in a silk-screen printing mode, a connecting assembly is arranged on the frame assembly, and the frame assembly is fixed through the connecting assembly. According to the invention, the plurality of layers of ceramic resistor discs are mounted in the frame assembly made of ceramic for lamination pressing production, so that the phenomenon that the lamination process or equipment slightly fluctuates in the production process of the laminated negative temperature coefficient thermistor is avoided; the problem that a certain layer of electrode or multiple layers of electrodes deviate along the length direction or the width direction of the porcelain body is solved, and the consistency, the stability and the reliability of the resistance value of the negative temperature coefficient thermistor are ensured.

Description

Technical Field

[0001] The invention relates to the technical field of thermistors, in particular to a stacked NTC thermistor with high stability. Background Art

[0002] Thermistor is a sensor resistor whose resistance value changes with temperature. NTC thermistor means negative temperature coefficient thermistor. When the temperature rises, the resistance value decreases. It is a semiconductor device and is often used in temperature measurement, temperature compensation and other occasions. With the miniaturization and integration trend of electronic products, the development of microelectronics technology and surface mount technology has been promoted. The chip-type of traditional bulk resistors, capacitors, inductors and other sensitive components is also an inevitable requirement and result of the development of surface mount technology. As one of the important sensitive components, thermistors are also developing in the direction of miniaturization, low resistance and stacking. The stacked negative temperature coefficient thermistor is a complex structure resistor composed of ceramic sheets and Ni inner electrodes alternately stacked. The use of a stacked structure through the superposition of multiple layers of materials can reduce the performance fluctuations caused by a single material, increase the reliability and stability of the thermistor, and improve the uniformity of the overall performance. At the same time, the stacked structure can also be designed according to specific application requirements to achieve specific resistance-temperature characteristics to meet different application scenarios. Since multiple ceramic sheets and multiple internal electrodes are stacked together to form a thermistor, when there is a slight fluctuation in the stacking process or equipment, a layer of electrode or multiple layers of electrodes may be displaced along the length or width of the porcelain body, and the unit resistance will be affected by the change in the area of ​​the adjacent electrode layers, thereby affecting the consistency of the product resistance and the stability and reliability of the product.

[0003] In order to avoid the electrode layer from being displaced along the length direction or the width direction of the porcelain body during processing, which affects the consistency of the product resistance and the stability of the product, the invention patent with application number CN202321836469.X provides a new type of chip NTC thermistor. The invention installs a multilayer ceramic sheet in a base one, and a telescopic plate is fixedly connected to the end face of the base one, and a base two is slidably sleeved on the other end of the telescopic plate. Cavities are opened on both sides of the base two, and a rotating block is hinged in the cavity. A ring sleeve is fixedly connected to the end face of the rotating block, and a push rod is slidably sleeved in the ring sleeve, and a spring is installed between the push rod and the rotating block. This chip NTC thermistor can accurately fix the ceramic resistance layer. Even if the stacking process or equipment fluctuations have no effect on the unit resistance, the overall stability of the unit resistance can be maintained at all times, which can fundamentally solve the impact of process or equipment fluctuations. At the same time, it can avoid the waste of wide and narrow electrodes, and can accurately determine the position of the internal electrodes and the area value of the facing area, thereby ensuring the consistency of the product resistance value and the stability and reliability of the product. However, since the base one and the base two are fixed by a rotating block, the top rod may fall off when the base is subjected to vibration force, and this fixing method is limited to a single stacked thermistor and cannot be mass-produced.

[0004] Therefore, in order to avoid the electrode layer being offset along the length direction or the width direction of the porcelain body during processing, which affects the consistency of the product resistance and the stability of the product, a stacked NTC thermistor with high stability is proposed. Summary of the invention

[0005] The object of the present invention is to provide a stacked NTC thermistor with high stability. In order to prevent a layer of electrode or a layer of electrodes from being displaced along the length direction or the width direction of a ceramic body when a stacking process or equipment has a slight fluctuation during the production process of the stacked negative temperature coefficient thermistor, and the unit resistance is affected by the change in the area of ​​the adjacent electrode layers, thereby affecting the resistance value of the negative temperature coefficient resistor, a multilayer ceramic resistor is installed in a frame assembly made of ceramic for stacking and pressing production, so as to avoid the problem of a layer of electrode or a layer of electrodes being displaced along the length direction or the width direction of a ceramic body, thereby ensuring the consistency, stability and reliability of the resistance value of the negative temperature coefficient thermistor.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A stacked NTC thermistor with high stability comprises a ceramic resistor, an inner electrode sheet and a frame assembly, wherein the frame assembly is made of ceramic material, the frame assembly comprises a first frame, a second frame and an upper frame, symmetrical connecting beams are arranged on both sides of the first frame, the connecting beams connect the two ends of the frame, a middle beam is arranged on the first frame, the width of the middle beam is arranged to be twice that of the connecting beam, the second frame and the first frame are arranged in a symmetrical shape, the upper frame is provided with connecting beams and middle beams corresponding to the first frame and the second frame, the upper frame is slidably mounted above the first frame and the second frame, the length of the upper frame is equal to the sum of the lengths of the first frame and the second frame, the plurality of ceramic resistor sheets are mounted inside the first frame and the second frame, the upper frame covers the plurality of ceramic resistor sheets, the plurality of ceramic resistor sheets are screen-printed with corresponding inner electrode sheets, a connecting assembly is mounted on the frame assembly, the connecting assembly connects the first frame and the second frame.

[0008] By stacking and pressing multilayer ceramic resistors to form a stacked negative temperature coefficient thermistor, the performance fluctuation caused by a single material can be reduced and the uniformity of the overall performance of the negative temperature coefficient thermistor can be improved. The inner electrode sheets screen-printed on the ceramic resistor sheets can be designed according to specific application requirements. By changing the number of alternating stacking and stacking distance of the inner electrode sheets, specific resistance-temperature characteristics can be achieved to meet different application scenarios. The multilayer ceramic resistor sheets are first slid and installed into frame one, and the side walls of the ceramic resistor sheets are fitted with the inner side walls of frame one, and the connecting beams of frame one are fitted with the edge lines of the bottom ceramic resistor sheets. After the multilayer ceramic resistor sheets are installed in frame one, frame two is slid and installed from the other end of the ceramic resistor sheets, and the other side walls of the ceramic resistor sheets are fitted with the inner side walls of frame two, and the connecting beams of frame two are fitted with the edge lines of the bottom ceramic resistor sheets. After one side wall of frame one is fitted with the side wall of frame two, the connecting assembly connects frame one to frame two. The relative position of the frame two is fixed, and the upper frame is slid downward from the top of the frame one and the frame two to fit the surface of the uppermost ceramic resistor. The rectangle formed by the frame assembly completely covers the multilayer ceramic sheets, restricting the longitudinal and lateral movement of each layer of the ceramic resistor, preventing the negative temperature coefficient thermistor from having slight fluctuations in the lamination process or equipment during the processing, and preventing a layer of electrode or multiple layers of electrodes from being offset along the length direction of the ceramic body or the width direction of the ceramic body, thereby preventing the unit resistance from being affected by the change in the area of ​​the adjacent electrode layer, and ensuring the consistency, stability and reliability of the resistance value of the negative temperature coefficient thermistor. When the lamination process is completed, the frame assembly can be cut into multiple equal stacked negative temperature coefficient thermistors, and then processed by subsequent processes. The frame assembly can position the ceramic resistor and enable batch production of the stacked negative temperature coefficient thermistors, thereby improving the production efficiency of the stacked negative temperature coefficient thermistors.

[0009] Preferably, two supporting base plates are symmetrically arranged on the frame one, and the supporting base plates are arranged in a T shape. The side walls of the supporting base plates are flush with the side walls of the frame one, and the width of the supporting base plates is the same as the width of the frame one. The frame two and the upper frame are both provided with supporting base plates corresponding to the frame one.

[0010] By setting a support base plate on the frame assembly, after the frame assembly is cut, each equal stacked negative temperature coefficient thermistor will have a support base plate at both ends. After the stacked negative temperature coefficient thermistor is processed, when the stacked negative temperature coefficient thermistor needs to be soldered to the circuit board, if there is excessive solder, the increase in the amount of solder will increase the pressure on the stacked negative temperature coefficient thermistor, which is caused by the shrinkage pressure generated by the solder, thereby causing cracks. However, if the amount of solder is too little, there will be a risk of poor contact or chip falling off, and the groove part formed by the connection between the support base plate and the frame assembly can absorb and store part of the solder, which can not only avoid the excessive solder at the end causing the solder to generate shrinkage pressure and cause cracks in the thermistor, but also prevent the poor contact of the thermistor or chip falling off due to too little solder.

[0011] Preferably, the connecting assembly includes a square block, a connecting plate, and a thrust spring. A connecting groove is opened in the square block. The connecting plate is rotatably installed in the connecting groove. The width of the connecting plate is equal to the width of the connecting groove. The end of the connecting plate extends out of the connecting groove and is arranged in an arc trapezoid. The bottom of the connecting plate is parallel to the end face of the connecting groove. One end of the thrust spring is connected to the end face of the connecting groove, and the other end is fixedly connected to the bottom of the connecting plate. Two square blocks are symmetrically installed on frame one and frame two, and the connecting plate on frame one and the connecting plate on frame two are installed in opposite directions.

[0012] By arranging the connection assembly on the frame assembly, when the multilayer ceramic resistor is installed on the frame one, the frame two is slidably installed from the other end of the ceramic resistor, and the relative distance between the frame one and the frame two gradually decreases. Since the end of the connection plate extends out of the connection groove, and the installation directions of the connection plates on the frame one and the frame two are opposite, the arc part of the arc trapezoid of the connection plate on the frame one first contacts the arc part of the arc trapezoid of the connection plate on the frame two and slides relatively, the connection plate on the frame one enters the connection groove on the frame two, and the connection plate on the frame two enters the connection groove on the frame one, the thrust spring is compressed, and the connection plate is limited in the connection groove. Rotate, when the square block on frame one fits with the side wall of the square block on frame two, the connecting plate on frame one and the connecting plate on frame two restore to a state parallel to the end face of the connecting groove under the thrust of the thrust spring. At this time, the arc trapezoidal vertical parts of the two connecting plates fit together, and the two connecting plates are clamped, limiting the lateral movement of frame one and frame two, and the width of the connecting plate is equal to the width of the connecting groove. After the two connecting plates are inserted into the connecting groove, the longitudinal movement of frame one and frame two is limited, avoiding relative displacement of the frame assembly due to vibration force or stress, maintaining the position and facing area value of the internal electrodes of the unit resistor, and improving the stability of the connection of the frame assembly.

[0013] Preferably, a rectangular groove is formed at the vertical connection between the support base plate and the frame assembly, and two vertical surfaces are present in the rectangular groove. When the frame assembly is subjected to the glass packaging process, the glass cladding covers the frame assembly, and the cross-section of the glass cladding is arc-shaped at the connection of the two vertical surfaces, and the thickness is greater than the glass cladding covering the connecting beam.

[0014] By using glass encapsulation materials to protect the internal porcelain body and internal electrodes before sintering the terminal electrodes of the stacked negative temperature coefficient thermistor, the performance deterioration caused by the intrusion of chemical plating liquid is prevented. This protection measure improves the pressure resistance and reliability of the thermistor. Before the support base is set, the glass encapsulation on the surface of the thermistor is a layer of glass cladding with uniform thickness, and the glass cladding is vertical at the corner of the edge of the thermistor. In the vertical direction, the two ends of the stacked negative temperature coefficient thermistor are generally more prominent than the middle part, so when the thermistor is welded and used The stress on both ends is greater, and the glass cladding at that location will be subjected to greater stress accordingly. When a supporting base plate is arranged on the frame assembly, due to the effect of liquid tension during the glass coating process, the glass cladding is in an arc shape at the connection between the supporting base plate and the connecting frame assembly, and its thickness is greater than that of ordinary glass cladding. Compared with the vertical glass cladding in a normal state, the arc-shaped glass cladding can resist greater stress, thereby preventing the glass cladding on the surface of the thermistor from being broken due to stress, and improving the stress resistance of the glass cladding at both ends of the stacked negative temperature coefficient thermistor.

[0015] Preferably, a rectangular groove 1 is symmetrically provided on the frame 1, and the rectangular groove is located on the side wall of one end of the frame 1, and a rectangular groove 2 is provided on the side wall of the other end of the frame 1, and the width of the rectangular groove 2 is half of the rectangular groove 1, and corresponding rectangular grooves 1 and 2 are provided on the frame 2, and the upper frame is symmetrically fixed with a plurality of rectangular blocks, and the plurality of rectangular blocks are respectively slidably matched with the rectangular groove 1 and the rectangular groove 2, and the length of the rectangular groove 1 is 0.5-1mm greater than the length of the rectangular block, and a connecting electrode layer is coated on one side wall of the frame, and the connecting electrode layer is in contact with the inner electrode sheet on the inner wall of the frame, and the upper frame is fitted with the upper end surface of the connecting electrode layer.

[0016] By providing rectangular groove 1 and rectangular groove 2 on frame 1 and frame 2, after the side walls of frame 1 and frame 2 are fitted together, the rectangular groove 2 on frame 1 and the rectangular groove 2 on frame 2 are fitted together, at this time, the size of the two rectangular grooves 2 is the same as the size of the rectangular groove 1, and the upper frame is provided with a plurality of rectangular blocks corresponding to the rectangular groove 1 and the rectangular groove 2, which is convenient for the sliding installation of the upper frame, and the length of the rectangular groove is greater than the length of the rectangular block, and after the upper frame is matched with frame 1 and frame 2, a gap is avoided between the upper frame and the uppermost ceramic resistor sheet, so that the frame assembly and the ceramic resistor sheet are more fitted, and the upper frame is set to be installed in a sliding matching manner, which is convenient for brushing a connecting electrode layer on the inner side walls of frame 1 and frame 2, and the connecting electrode layer is convenient for the connection between the inner electrode sheet and the outer electrode, thereby simplifying the production steps and improving the production efficiency of the stacked negative temperature coefficient thermistor.

[0017] Preferably, two guide rods are symmetrically fixedly installed under the square block, and the two guide rods are in contact with the inner wall of the supporting base plate. Two clip-on strips are arranged on the lower side of the square block, and the two clip-on strips are made of rubber material. The distance between the two clip-on strips is smaller than the width of the connecting beam, and the clip-on strips are slidably matched with the connecting beam.

[0018] By arranging guide rods and snap-in strips on the square blocks, when the connecting assembly is installed on the frame assembly, the guide rods are inserted into the connection between the supporting base plate and the frame assembly, and the guide rods play a positioning and guiding role. The square blocks are then snapped onto the connecting beams through snap-in strips made of rubber. The spacing between the snap-in strips is smaller than the width of the connecting beams, thereby increasing the friction between the snap-in strips and the connecting beams and improving the stability of the connection. The connecting assembly is detachably installed on the frame assembly using the guide rods and snap-in strips. The connecting assembly is installed when frame one and frame two need to be connected, and is removed when the frame assembly is cut. The connecting assembly can be reused many times, thereby reducing production costs.

[0019] Preferably, two limit blocks are symmetrically fixedly installed on the side wall at one end of the frame, the limit blocks are located above the connecting assembly, and corresponding limit grooves are opened on the side wall at one end of the frame, and the limit blocks are slidably connected to the limit grooves.

[0020] By arranging a limit block above the connection component and slidingly connecting it with the limit groove, it is avoided that the connection plate rotates when bending stress occurs at the connection tangent of the connection component, causing the connection component to loosen, thereby improving the stability of the connection between frame one and frame two.

[0021] Preferably, a through hole is provided at the upper end of the square block, the through hole penetrates into the connecting groove, a circular hole corresponding to the through hole is provided on the connecting plate, a cylindrical pin is slidably mounted on the square block, and the cylindrical pin is coaxially matched with the through hole and the circular hole.

[0022] By sliding the cylindrical pin on the square block, the cylindrical pin is in the through hole when the connecting plates on frame one and frame two are not yet connected. When the two connecting plates are snapped together, the cylindrical pin is inserted into the round hole to completely lock the connection between the two square blocks, thereby preventing the elastically connected connecting plates from vibrating and affecting the fixing effect of the connecting assembly, thereby further improving the stability of the connecting assembly.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. By setting up a frame assembly to completely cover the multilayer ceramic sheet, the longitudinal and lateral movement of each layer of ceramic resistor is limited to prevent the negative temperature coefficient thermistor from having slight fluctuations in the lamination process or equipment during the processing. A layer of electrode or multiple layers of electrodes may be offset along the length direction or width direction of the ceramic body, avoiding the unit resistance from being affected by the change in the area of ​​the adjacent electrode layer, and ensuring the consistency, stability and reliability of the resistance value of the negative temperature coefficient thermistor.

[0025] 2. By setting a supporting base plate on the frame assembly, the groove formed by the connection between the supporting base plate and the frame assembly can absorb and store part of the solder, which can not only avoid excessive solder at the end causing shrinkage pressure of the solder to cause cracks in the thermistor, but also prevent too little solder from causing poor contact of the thermistor or falling off of the chip.

[0026] 3. By setting a connecting component on the frame component, the frame component is prevented from relative displacement due to vibration force or stress, the position and facing area value of the internal electrodes of the unit resistor are maintained, and the stability of the connection of the frame component is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0028] Figure 2 It is a bottom view of the overall structure of the present invention;

[0029] Figure 3 A schematic diagram of the stacking of ceramic resistor sheets of the present invention;

[0030] Figure 4 It is a schematic diagram of the structure of the frame assembly of the present invention;

[0031] Figure 5 It is a cutaway schematic diagram of the present invention;

[0032] Figure 6 is a schematic diagram of the glass cladding of the present invention;

[0033] Figure 7 It is a schematic diagram of the structure of the connection assembly of the present invention;

[0034] Figure 8 This is a schematic diagram of the frame assembly of the present invention after cutting.

[0035] In the figure: 1. Ceramic resistor; 2. Inner electrode sheet; 3. Frame assembly; 31. Frame one; 311. Rectangular groove one; 312. Rectangular groove two; 313. Support base plate; 314. Connecting electrode layer; 315. Limit block; 32. Frame two; 321. Limit groove; 33. Upper frame; 331. Rectangular block; 34. Connecting beam; 35. Middle beam; 4. Connecting assembly; 41. Square block; 411. Connecting groove; 412. Guide rod; 413. Snap-in strip; 414. Through hole; 415. Cylindrical pin; 42. Connecting plate; 421. Round hole; 43. Thrust spring; 5. Glass cladding. DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] In the description of the present invention, it is to be understood that the terms "both sides", "symmetrical", "upper", "longitudinal", "lateral", "flush", "opposite", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0038] See also Figures 1 to 8 The present invention provides a high-stability laminated NTC thermistor, and the technical solution is as follows:

[0039] When the pressing process is performed on the multiple ceramic resistor sheets 1, the multiple ceramic resistor sheets 1 are first slidably installed into the frame assembly 3. The frame assembly 3 includes a frame 1 31, a frame 2 32, and an upper frame 33. Symmetrical connecting beams 34 are arranged on both sides of the frame 1 31. The connecting beams 34 connect the two ends of the frame. A middle beam 35 is arranged on the frame 1 31. The width of the middle beam 35 is set to be twice that of the connecting beam 34. After the frame assembly 3 is cut from the middle, the width of the middle beam divided into two is the same as the width of the connecting beam 34. The frame 2 32 and the frame 1 31 are set to a symmetrical shape. The upper frame 33 is provided with connecting beams 34 and middle beams 35 corresponding to the frame 1 31 and the frame 2 32. The upper frame 33 is slidably installed above the frame 1 31 and the frame 2 32. The length of the frame 33 is equal to the sum of the lengths of the frame 1 31 and the frame 2 32. Multiple ceramic resistors 1 are installed inside the frame 1 31 and the frame 2 32. The upper frame 33 covers the multiple ceramic resistors 1. The multiple ceramic resistors 1 are screen-printed with corresponding inner electrode sheets 2. The frame assembly 3 is provided with a connecting assembly 4. The connecting assembly 4 connects the frame 1 31 and the frame 2 32 so that the side walls of the frame 1 31 and the frame 2 32 are attached. The multilayer ceramic resistors 1 are stacked and pressed to form a stacked negative temperature coefficient thermistor, which can reduce the performance fluctuation caused by a single material and improve the uniformity of the overall performance of the negative temperature coefficient thermistor. The inner electrode sheet 2 screen-printed on the ceramic resistor 1 can be designed according to specific application requirements, and the inner electrode sheet 2 can be changed. The number of alternating stacking layers and the stacking distance can achieve specific resistance-temperature characteristics to meet different application scenarios. The multilayer ceramic resistor 1 is first slidably installed in the frame 1 31, and the side wall of the ceramic resistor 1 is fitted with the inner wall of the frame 1 31. The connecting beam 34 of the frame 1 31 is fitted with the edge line of the bottom ceramic resistor 1. After the multilayer ceramic resistor 1 is installed in the frame 1 31, the frame 2 32 is slidably installed from the other end of the ceramic resistor 1. The other side wall of the ceramic resistor 1 is fitted with the inner wall of the frame 2 32. The connecting beam 34 of the frame 2 32 is fitted with the edge line of the bottom ceramic resistor 1. After one side wall of the frame 1 31 is fitted with the side wall of the frame 2 32, the connecting component 4 fixes the relative position of the frame 1 31 and the frame 2 32. The frame 33 is installed by sliding downward from the top of the frame 1 31 and the frame 2 32, and is fitted with the surface of the topmost ceramic resistor 1. The rectangle formed by the frame assembly 3 completely covers the multilayer ceramic sheets, restricting the longitudinal and lateral movement of each layer of the ceramic resistor 1, preventing the negative temperature coefficient thermistor from having slight fluctuations in the lamination process or equipment during the processing, and preventing a layer of electrode or multiple layers of electrodes from being offset along the length direction or width direction of the ceramic body, thereby preventing the unit resistance from being affected by the change in the area of ​​the adjacent electrode layers, and ensuring the consistency, stability and reliability of the resistance value of the negative temperature coefficient thermistor. After the lamination process is completed, the frame assembly 3 can be cut into multiple equal laminated negative temperature coefficient thermistors, and then processed by subsequent processes.The frame assembly 3 can position the ceramic resistor 1 while enabling batch production of the stacked negative temperature coefficient thermistors, thereby improving the production efficiency of the stacked negative temperature coefficient thermistors; two supporting base plates 313 are symmetrically arranged on the frame 1 31, and the supporting base plates 313 are arranged in a T-shape. The side walls of the supporting base plates 313 are flush with the side walls of the frame 1 31, and the width of the supporting base plates 313 is the same as the width of the frame 1 31. The frame 2 32 and the upper frame 33 are both provided with supporting base plates 313 corresponding to the frame 1 31. After the cutting of the frame assembly 3 is completed, both ends of each equal stacked negative temperature coefficient thermistor will have supporting base plates 313. After the stacked negative temperature coefficient thermistor is processed, when the stacked negative temperature coefficient thermistor needs to be welded to the circuit board, if the solder is excessive, the increase in the amount of solder will increase the pressure on the stacked negative temperature coefficient thermistor, which is caused by the shrinkage pressure generated by the solder, thereby causing cracks. However, if the amount of solder is too little, there will be a risk of poor contact or chip falling off, and the groove portion formed by the connection between the support base plate 313 and the frame component 3 can absorb and store part of the solder, which can not only avoid the shrinkage pressure of the solder caused by excessive solder at the end to cause cracks in the thermistor, but also prevent the poor contact of the thermistor or chip falling off caused by too little solder; when the stacked thermistor is glass packaged, the glass cladding 5 covers the frame component 3, and the glass cladding 5 is arc-shaped at the connection between the support base plate 313 and the frame component 3, and the thickness is greater than the glass cladding 5 covering the connecting beam 34. Before the stacked negative temperature coefficient thermistor is sintered with the end electrode process, the internal porcelain body and the internal electrode are protected by glass packaging material to prevent the intrusion of chemical plating solution and cause performance deterioration. This protection measure improves the pressure resistance and reliability of the thermistor. Before the support base plate 313 is set, the glass is encapsulated on the surface of the thermistor as a layer of glass cladding 5 with uniform thickness, and the glass cladding 5 is at the corner of the edge of the thermistor. The two ends of the stacked negative temperature coefficient thermistor are generally more prominent than the middle part in the vertical direction, so the two ends are subjected to greater stress when the thermistor is welded and used, and the glass cladding 5 at this place will be subjected to greater stress accordingly. After the support base plate 313 is set on the frame assembly 3, due to the effect of liquid tension during the glass coating process, the glass cladding 5 is arc-shaped at the connection between the support base plate 313 and the connecting frame assembly 3, and the thickness is greater than the ordinary glass cladding 5. Compared with the glass cladding 5 in a vertical state under normal conditions, the arc-shaped glass cladding 5 can resist greater stress, avoid the glass cladding 5 on the surface of the thermistor from being broken due to stress, and improve the stress resistance of the glass cladding 5 at both ends of the stacked negative temperature coefficient thermistor; rectangular grooves 311 are symmetrically opened on the frame 1 31, and the rectangular grooves are located on the side wall of one end of the frame 1 31, and rectangular grooves 2 312 are opened on the side wall of the other end of the frame 1 31, and the width of the rectangular grooves 2 312 is half of the rectangular grooves 1 311.The frame 32 is provided with corresponding rectangular grooves 1 311 and 2 312, and the upper frame 33 is symmetrically fixed with a plurality of rectangular blocks 331, which are respectively slidably matched with the rectangular grooves 1 311 and 2 312, and the length of the rectangular grooves 1 311 is greater than the length of the rectangular blocks 331 by 0.5 mm. The side wall of the frame 31 is coated with a connecting electrode layer 314, and the connecting electrode layer 314 is in contact with the inner electrode sheet 2 on the inner wall of the frame 1 31, and the upper frame 33 is fitted with the upper end surface of the connecting electrode layer 314. After the side walls of the frame 1 31 and the frame 2 32 are fitted together, the rectangular grooves 2 312 on the frame 1 31 and the rectangular grooves 2 312 on the frame 2 32 are fitted with each other. At this time, the two rectangular grooves 2 312 The size is the same as that of the rectangular groove 1 311. The upper frame 33 is provided with a plurality of rectangular blocks 331 corresponding to the rectangular groove 1 311 and the rectangular groove 2 312, which facilitates the sliding installation of the upper frame 33. The length of the rectangular groove is greater than the length of the rectangular block 331. After the upper frame 33 is matched with the frame 1 31 and the frame 2 32, a gap is avoided between the upper frame 33 and the top ceramic resistor 1, so that the frame assembly 3 and the ceramic resistor 1 are more closely fitted. The upper frame 33 is set to be installed in a sliding fit, which is convenient for brushing the connecting electrode layer 314 on the inner side wall of the frame 1 31 and the frame 2 32. The connecting electrode layer 314 facilitates the connection between the inner electrode sheet 2 and the outer electrode, simplifies the production steps, and improves the production efficiency of the stacked negative temperature coefficient thermistor.

[0040] As an embodiment of the present invention, refer to Figures 4 to 8The connecting assembly 4 includes a square block 41, a connecting plate 42, and a thrust spring 43. A connecting groove 411 is provided in the square block 41. The connecting plate 42 is rotatably installed in the connecting groove 411. The width of the connecting plate 42 is equal to the width of the connecting groove 411. The end of the connecting plate 42 extends out of the connecting groove 411 and is set to be an arc trapezoid. The bottom of the connecting plate 42 is parallel to the end face of the connecting groove 411. One end of the thrust spring 43 is connected to the end face of the connecting groove 411, and the other end is fixedly connected to the bottom of the connecting plate 42. Two square blocks are symmetrically installed on the frame 1 31 and the frame 2 32. The connection plate 42 on the frame 1 31 is installed in opposite directions to the connection plate 42 on the frame 2 32. When the multilayer ceramic resistor 1 is installed on the frame 1 31, the frame 2 32 is slidably installed from the other end of the ceramic resistor 1, and the relative distance between the frame 1 31 and the frame 2 32 is gradually reduced. Since the end of the connection plate 42 extends out of the connection groove 411, and the connection plates 42 on the frame 1 31 and the frame 2 32 are installed in opposite directions, the arc part of the arc trapezoid of the connection plate 42 on the frame 1 31 is first connected to the connection plate 42 on the frame 2 32. The arc parts of the arc trapezoid of the plate 42 contact and slide relative to each other, the connecting plate 42 on the frame 1 31 enters the connecting groove 411 on the frame 2 32, the connecting plate 42 on the frame 2 32 enters the connecting groove 411 on the frame 1 31, the thrust spring 43 is compressed, and the connecting plate 42 rotates within the connecting groove 411. When the square block 41 on the frame 1 31 fits with the side wall of the square block 41 on the frame 2 32, the connecting plate 42 on the frame 1 31 and the connecting plate 42 on the frame 2 32 are restored under the thrust of the thrust spring 43. The two connecting plates 42 are parallel to the end surface of the connecting groove 411. At this time, the arc trapezoidal vertical parts of the two connecting plates 42 are fitted, and the two connecting plates 42 are connected to each other, which limits the horizontal movement of the frame 1 31 and the frame 2 32. The width of the connecting plate 42 is equal to the width of the connecting groove 411. After the two connecting plates 42 are inserted into the connecting groove 411, the vertical movement of the frame 1 31 and the frame 2 32 is limited, so as to prevent the relative displacement of the frame assembly 3 due to vibration force or stress, maintain the position and the facing area value of the internal electrodes of the unit resistor, and improve the stability of the connection of the frame assembly 3;Two guide rods 412 are symmetrically fixedly installed under the square block 41. The two guide rods 412 are in contact with the inner side wall of the support base plate 313. Two clip strips 413 are arranged on the lower side of the square block 41. The two clip strips 413 are made of rubber material, and the distance between the two clip strips 413 is smaller than the width of the connecting beam 34. The clip strips 413 and the connecting beam 34 are slidably matched. When the connecting assembly 4 is installed on the frame assembly 3, the guide rods 412 are inserted into the connection between the support base plate 313 and the frame assembly 3. The guide rods 412 play a positioning and guiding role, and the square The block 41 is then clamped on the connecting beam 34 through a clamping strip 413 made of rubber. The spacing between the clamping strips 413 is smaller than the width of the connecting beam 34, which increases the friction between the clamping strips 413 and the connecting beam 34 and improves the stability of the connection. The connecting assembly 4 is detachably installed on the frame assembly 3 using the guide rod 412 and the clamping strip 413. When the frame 1 31 and the frame 2 32 need to be connected, the connecting assembly 4 is installed. When the frame assembly 3 is cut, the connecting assembly 4 is removed. The connecting assembly 4 can be reused many times to reduce the production cost; the frame 1 31 and the frame 2 32 need to be connected. Two limit blocks 315 are symmetrically fixedly installed on the side wall at one end of the frame 1, and the limit blocks 315 are located above the connecting component 4. A corresponding limit groove 321 is provided on the side wall at one end of the frame 2 32. The limit blocks 315 are slidably connected with the limit groove 321 to prevent the connecting plate 42 from rotating when bending stress occurs at the connecting tangent of the connecting component 4, causing the connecting component 4 to loosen, thereby improving the stability of the connection between the frame 1 31 and the frame 2 32; a through hole 414 is provided at the upper end of the square block 41, and the through hole 414 penetrates the connecting groove 411, and a through hole 414 is provided on the connecting plate 42 There is a circular hole 421 corresponding to the through hole 414, and a cylindrical pin 415 is slidably installed on the square block 41. The cylindrical pin 415 is coaxially matched with the through hole 414 and the circular hole 421. When the connecting plates 42 on the frame 1 31 and the frame 2 32 are not connected, the cylindrical pin 415 is in the through hole 414. When the two connecting plates 42 are clamped, the cylindrical pin 415 is inserted into the circular hole 421, and the connection between the two square blocks 41 is completely locked, so as to prevent the elastically connected connecting plates 42 from vibrating and affecting the fixing effect of the connecting assembly 4, and further improve the stability of the connecting assembly 4. ;

[0041] Working principle: first insert the guide rod 412 on the square block 41 between the support base plate 313 and the frame assembly 3, then fix the square block 41 on the connecting beam 34 with the clamping strip 413, slide the multilayer ceramic resistor 1 into the frame 1 31, then slide the frame 2 32 from both ends of the ceramic resistor 1, the other side wall of the ceramic resistor 1 fits with the inner side wall of the frame 2 32, the connecting beam 34 of the frame 2 32 fits with the edge line of the bottom ceramic resistor 1, and the frame 1 31 fits with the frame 2 32. The relative distance between the frame 2 and the frame 32 gradually decreases, the limit block 315 on the frame 1 31 slides with the limit groove 321 on the frame 2 32, the arc part of the arc trapezoid of the connecting plate 42 on the frame 1 31 first contacts with the arc part of the arc trapezoid of the connecting plate 42 on the frame 2 32 and slides relatively, the connecting plate 42 on the frame 1 31 enters the connecting groove 411 on the frame 2 32, the connecting plate 42 on the frame 2 32 enters the connecting groove 411 on the frame 1 31, and the thrust spring 43 is compressed, and the connecting plate 42 rotates within the connecting groove 411. When the square block 41 on the frame 1 31 fits with the side wall of the square block 41 on the frame 2 32, the connecting plate 42 on the frame 1 31 and the connecting plate 42 on the frame 2 32 restore to a state parallel to the end face of the connecting groove 411 under the thrust of the thrust spring 43. At this time, the arc trapezoidal vertical parts of the two connecting plates 42 fit together, and the two connecting plates 42 are snap-fitted. Then the upper frame 33 is installed on the frame 1 31 and the frame 2 32, and the rectangular block 331 slides with the rectangular groove 1 311 and the rectangular groove 2 312. After the frame assembly 3 completely covers the multilayer ceramic resistor 1, the unit resistor is sent into the pressing process. After the pressing of the multilayer ceramic resistor 1 is completed, the connecting assembly 4 is removed from the frame assembly 3, and then the unit resistor is cut. First, the center line of the middle beam is cut, and then the middle part of the upper frame 33 is cut to cut a unit resistor into four equally divided stacked negative temperature coefficient thermistors.

[0042] A specific embodiment of the present invention is described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above described embodiment. For those skilled in the art, various changes, modifications, substitutions and variations of these embodiments without departing from the principles and ideas of the present invention should still fall within the scope of protection of the present invention.

Claims

1. A stacked NTC thermistor with high stability, characterized in that: The invention comprises a ceramic resistor sheet (1), an inner electrode sheet (2), and a frame assembly (3), wherein the frame assembly (3) is made of ceramic material, the frame assembly (3) comprises a first frame (31), a second frame (32), and an upper frame (33), symmetrical connecting beams (34) are arranged on both sides of the first frame (31), the connecting beams (34) connect the two ends of the frame, a middle beam (35) is arranged on the first frame (31), the width of the middle beam (35) is arranged to be twice that of the connecting beam (34), the second frame (32) and the first frame (31) are arranged to be symmetrical in shape, and the upper frame (33) is arranged to be connected to the first frame (31) and the second frame (32). ) corresponding connecting beams (34) and middle beams (35), the upper frame (33) is slidably mounted above frame one (31) and frame two (32), the length of the upper frame (33) is equal to the sum of the lengths of frame one (31) and frame two (32), the plurality of ceramic resistor sheets (1) are mounted inside frame one (31) and frame two (32), the upper frame (33) covers the plurality of ceramic resistor sheets (1), the plurality of ceramic resistor sheets (1) are screen-printed with corresponding inner electrode sheets (2), the frame assembly (3) is mounted with a connecting assembly (4), the connecting assembly (4) connects frame one (31) and frame two (32).

2. A stacked NTC thermistor with high stability according to claim 1, characterized in that: Two supporting bottom plates (313) are symmetrically arranged on the frame one (31), and the supporting bottom plates (313) are arranged in a T shape. The side walls of the supporting bottom plates (313) are flush with the side walls of the frame one (31), and the width of the supporting bottom plates (313) is the same as the width of the frame one (31). The frame two (32) and the upper frame (33) are both provided with supporting bottom plates (313) corresponding to the frame one (31).

3. A stacked NTC thermistor with high stability according to claim 2, characterized in that: The connecting assembly (4) comprises a square block (41), a connecting plate (42), and a thrust spring (43). A connecting groove (411) is provided in the square block (41). The connecting plate (42) is rotatably mounted in the connecting groove (411). The width of the connecting plate (42) is equal to the width of the connecting groove (411). The end of the connecting plate (42) extends out of the connecting groove (411) and is arranged in a circular arc trapezoid. The bottom of the connecting plate (42) is parallel to the end surface of the connecting groove (411). One end of the thrust spring (43) is connected to the end surface of the connecting groove (411), and the other end is fixedly connected to the bottom of the connecting plate (42). Two square blocks (41) are symmetrically mounted on the first frame (31) and the second frame (32). The connecting plate (42) on the first frame (31) and the connecting plate (42) on the second frame (32) are mounted in opposite directions.

4. A stacked NTC thermistor with high stability according to claim 2, characterized in that: A rectangular groove is formed at the vertical connection between the support base plate (313) and the frame assembly (3), and two vertical surfaces are present in the rectangular groove. When the frame assembly (3) is subjected to a glass encapsulation process, a glass cladding (5) covers the frame assembly (3), and the cross section of the glass cladding (5) is in an arc shape at the connection of the two vertical surfaces, and the thickness is greater than that of the glass cladding (5) covering the connection beam (34).

5. A stacked NTC thermistor with high stability according to claim 2, characterized in that: The frame 1 (31) is symmetrically provided with a rectangular groove 1 (311), the rectangular groove is located on one end side wall of the frame 1 (31), the other end side wall of the frame 1 (31) is provided with a rectangular groove 2 (312), the width of the rectangular groove 2 (312) is half of the rectangular groove 1 (311), the frame 2 (32) is provided with corresponding rectangular groove 1 (311) and rectangular groove 2 (312), the upper frame (33) is symmetrically fixedly provided with a plurality of rectangular blocks (33 1), the plurality of rectangular blocks (331) are respectively slidably matched with the rectangular groove one (311) and the rectangular groove two (312), the length of the rectangular groove one (311) is 0.5-1 mm greater than the length of the rectangular block (331), the side wall of the frame one (31) is coated with a connecting electrode layer (314), the connecting electrode layer (314) is in contact with the inner electrode sheet (2) located on the inner wall of the frame one (31), and the upper frame (33) is in contact with the upper end surface of the connecting electrode layer (314).

6. A stacked NTC thermistor with high stability according to claim 3, characterized in that: Two guide rods (412) are symmetrically fixedly installed below the square block (41), and the two guide rods (412) are in contact with the inner side wall of the supporting bottom plate (313). Two clamping strips (413) are arranged on the lower side of the square block (41), and the two clamping strips (413) are made of rubber material. The distance between the two clamping strips (413) is smaller than the width of the connecting beam (34), and the clamping strips (413) are slidably matched with the connecting beam (34).

7. A stacked NTC thermistor with high stability according to claim 5, characterized in that: Two limit blocks (315) are symmetrically fixedly installed on the side wall at one end of the frame (31), and the limit blocks (315) are located above the connecting assembly (4). A corresponding limit groove (321) is opened on the side wall at one end of the frame (32), and the limit blocks (315) are slidably connected to the limit groove (321).

8. A stacked NTC thermistor with high stability according to claim 3, characterized in that: A through hole (414) is provided at the upper end of the square block (41), and the through hole (414) penetrates into the connecting groove (411). A circular hole (421) corresponding to the through hole (414) is provided on the connecting plate (42). A cylindrical pin (415) is slidably mounted on the square block (41), and the cylindrical pin (415) is coaxially matched with the through hole (414) and the circular hole (421).

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