A square thyristor chip

Abstract

The present invention provides a square thyristor chip, which relates to the field of electrical engineering and includes: a mounting main board, a chip base, a chip cover, an anode plate, a chip silicon wafer, a cathode plate, a chip gate, a chip mounting mechanism, and a chip protection mechanism; the chip base is located on the upper end surface of the mounting main board; the chip cover is located on the upper end surface of the chip base; the anode plate is located on the inner end surface; the chip silicon wafer is fixedly connected to the upper end surface of the anode plate; the cathode plate is fixedly connected to the upper end surface of the chip silicon wafer; the chip gate is fixedly connected to the inner side of the cathode plate; the chip mounting mechanism is arranged inside the chip base; the chip protection mechanism is arranged on the outer end surface of the chip base. Through the chip mounting mechanism, it is convenient for workers to install the thyristor chip. Through the chip protection mechanism, the transportation safety of the chip pins is improved. The problem that the pin structure of the thyristor chip is easily bent when the thyristor chip is impacted, which easily causes damage to the square thyristor chip, is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of electrical engineering, and particularly relates to a square thyristor chip. Background Art

[0002] A thyristor is a power semiconductor device. Inside the thyristor, there are components such as a square thyristor chip and a main board. The square thyristor chip is the core component of the thyristor. The square thyristor chip is electrically fused and installed on the main board through chip pins. The square thyristor chip determines the performance parameters of the thyristor and enables efficient control of current and voltage.

[0003] According to CN201620654064.8, the present utility model discloses a thyristor chip in the field of electronic chips, which includes a chip fixed on a substrate frame. The substrate frame includes a first pin, a second pin, a third pin, and a base island. The chip is fixed on the base island. The second pin is fixedly connected to the base island. The first pin is arranged on one side of the base island in an extending manner, and the third pin is arranged at the bottom of the base island in an extending manner. The ends of the first pin and the second pin are both plated with a silver protective layer. The chip is connected to the first pin and the second pin through bonding wires. The substrate frame, the chip, and the bonding wires are encapsulated in a plastic package. The structure of the present utility model is simple, reducing the cost of electronic circuits. By arranging the first pin and the second pin to extend into the side and bottom of the base island respectively, the chip has better integration, and at the same time, it is convenient for the encapsulation of the chip and can be used in various electrical products.

[0004] However, the square thyristor chip is generally connected to the main board inside the thyristor through a pin structure. The pin structure is arranged on both sides of the outer end face of the chip. The pin structure is generally thin and long, and the pin structure is prone to bending. The square thyristor chip is easily impacted during transportation. When the square thyristor chip is impacted, it is easy to cause the pin structure to bend, which easily leads to damage to the square thyristor chip and affects the use of the square thyristor chip. Summary of the Invention

[0005] In view of this, the present invention provides a square thyristor chip, which has a bottom slider located outside the lower end face of the protective cover, comprehensively protecting the chip pins, avoiding the problem that the chip pins of the thyristor chip are bent due to impact during transportation and affecting the use, and improving the safety of the chip pins during transportation.

[0006] The present invention provides the purpose and efficacy of a square thyristor chip, which specifically includes: a mounting main board, a chip base, a chip cover, an anode plate, a chip silicon wafer, a cathode plate, a chip gate, a protective cover, a chip mounting mechanism, and a chip protection mechanism; the chip base is located on the upper end surface of the mounting main board; the chip cover is located at the middle position on the upper end surface of the chip base; the anode plate is located at the middle position of the inner end surface; the chip silicon wafer is fixedly connected to the middle position of the upper end surface of the anode plate; the cathode plate is fixedly connected to the middle position of the upper end surface of the chip silicon wafer; the chip gate is fixedly connected to the inner side of the cathode plate; there are two groups of protective covers, and the two groups of protective covers are respectively located on the front and rear end surfaces of the chip base; the chip mounting mechanism is arranged inside the chip base; there are two groups of chip protection mechanisms, and the two groups of chip protection mechanisms are respectively arranged on the front and rear end surfaces of the chip base.

[0007] Further, the chip mounting mechanism includes: a connection slot and a connection block; the connection slot is opened on the inner side of the upper end surface of the chip base; the connection block is fixedly connected to the lower end surface of the chip cover, and the connection slot and the connection block are plugged and connected.

[0008] Further, the chip mounting mechanism further includes: a mounting groove and thermal conductive silicone; the mounting groove is opened at the middle position of the inner end surface of the chip base, and the anode plate is plugged and connected inside the mounting groove; the thermal conductive silicone is adhesively connected to the inner end surface of the chip base and the outer end surface of the anode plate.

[0009] Further, the chip mounting mechanism further includes: contact foot grooves and chip contact feet; there are multiple groups of contact foot grooves, and the multiple groups of contact foot grooves are respectively opened on the front and rear end surfaces of the chip base; there are multiple groups of chip contact feet, and the multiple groups of chip contact feet are respectively fixedly connected to the front and rear end surfaces of the chip silicon wafer. The multiple groups of chip contact feet are respectively plugged and connected to the multiple groups of contact foot grooves. The outer sides of the multiple groups of chip contact feet are located on the front and rear end surfaces of the chip base, and the multiple groups of chip contact feet are respectively located on the inner end surfaces of the two groups of protective covers.

[0010] Further, the chip mounting mechanism further includes: positioning grooves and positioning bumps; there are four groups of positioning grooves, and the four groups of positioning grooves are respectively opened on the upper end surface of the mounting main board; there are four groups of positioning bumps, and the four groups of positioning bumps are respectively fixedly connected to the outer sides of the lower end surfaces of the four groups of chip contact feet. The four groups of positioning grooves are respectively plugged and connected to the four groups of positioning bumps.

[0011] Further, the chip protection mechanism includes: protection slots and protection blocks; there are two groups of protection slots, and the two groups of protection slots are respectively opened on the left and right sides of the outer end surface of the chip base; there are two groups of protection blocks, and the two groups of protection blocks are respectively fixedly connected to the left and right sides of the inner end surface of the protective cover. The two groups of protection slots are respectively plugged and connected to the two groups of protection blocks.

[0012] Further, the chip protection mechanism further includes: a stable slot and a stable plug; the stable slot is opened on the outer end surface of the right set of protection plugs; the stable plug is slidably connected to the inside of the outer end surface of the chip base, and the stable slot and the stable plug are plugged and connected.

[0013] Further, the chip protection mechanism further includes: a stable break block and a stable spring; the stable break block is slidably connected to the inside of the outer end surface of the chip base, the stable break block slides on the outer end surface, and the stable plug and the stable break block are fixedly connected; the stable spring is fixedly connected to the inside of the outer end surface of the chip base, and the stable break block and the stable spring are elastically connected.

[0014] Further, the chip protection mechanism further includes: bottom sliders and bottom springs; there are two groups of bottom sliders in total, and the two groups of bottom sliders are respectively slidably connected to the inside of the left and right sides of the lower end surface of the protection cover, and the two groups of bottom sliders respectively slide on the left and right sides of the lower end surface of the protection cover; there are two groups of bottom springs in total, and the two groups of bottom springs are respectively fixedly connected to the left and right sides inside the protection cover, and the two groups of bottom springs are respectively elastically connected to the upper end surfaces of the two groups of bottom sliders.

[0015] Beneficial effects

[0016] By adopting the chip installation mechanism in the present invention, when the anode plate, the chip silicon wafer and the cathode plate are installed inside the chip base, they are fixed by thermal conductive silicone. The chip silicon wafer is installed inside the chip base, and then the chip pins and the chip silicon wafer are connected through the pin grooves. Then, the staff can quickly place the thyristor chip on the installation main board through the positioning grooves and the positioning protrusions, ensuring that the thyristor chip will not move randomly on the installation main board, which is convenient for the staff to fix the thyristor chip on the installation main board and facilitates the staff to install the thyristor chip.

[0017] In addition, by adopting the chip protection mechanism, when the thyristor chip is transported and installed, the protection cover protects the outside of the chip pins, and the protection cover protects the chip pins inside. When the thyristor chip is transported, the bottom sliders are located outside the lower end surface of the protection cover, comprehensively protecting the chip pins and avoiding the problem that the chip pins are bent due to impact during the transportation of the thyristor chip, which affects the use, and improving the safety of the chip pin transportation. Description of the drawings

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings of the embodiments will be briefly introduced below.

[0019] The drawings in the following description only relate to some embodiments of the present invention and do not limit the present invention.

[0020] In the drawings:

[0021] Figure 1 It is a schematic diagram of the isometric structure of a square thyristor chip according to an embodiment of the present invention.

[0022] Figure 2 It is a schematic diagram of the bottom view structure of a square thyristor chip according to an embodiment of the present invention.

[0023] Figure 3 It is a schematic diagram of the disassembled structure of a square thyristor chip according to an embodiment of the present invention.

[0024] Figure 4 It is a schematic diagram of the disassembled structure of a chip mounting mechanism according to an embodiment of the present invention.

[0025] Figure 5 It is a schematic diagram of the structure of a mounting main board and chip pins according to an embodiment of the present invention.

[0026] Figure 6 It is a schematic diagram of the structure of a chip protection mechanism part according to an embodiment of the present invention.

[0027] Figure 7 It is a schematic diagram of the structure of the connection part of a protective cover according to an embodiment of the present invention.

[0028] Figure 8 It is a schematic diagram of the disassembled bottom view of a protective cover according to an embodiment of the present invention.

[0029] List of reference numerals

[0030] 1. Mounting main board; 101. Positioning groove; 2. Chip base; 201. Connection slot; 202. Pin groove; 203. Protection slot; 3. Chip cover; 301. Connection plug; 4. Anode plate; 5. Chip silicon wafer; 6. Cathode plate; 7. Chip gate; 8. Mounting groove; 9. Thermal conductive silicone; 10. Chip pins; 1001. Positioning bump; 11. Protective cover; 12. Protection plug; 1201. Stabilizing slot; 13. Stabilizing plug; 14. Stabilizing break block; 1401. Stabilizing spring; 15. Bottom slider; 1501. Bottom spring. Detailed implementation manners

[0031] Example 1: Please refer to Figures 1 to 5 as shown:

[0032] The present invention provides a square thyristor chip, including a mounting main board 1, a chip base 2, a chip cover 3, an anode plate 4, a chip silicon wafer 5, a cathode plate 6, a chip gate 7, a protective cover 11 and a chip mounting mechanism; the chip base 2 is located on the upper end face of the mounting main board 1; the chip cover 3 is located at the middle position of the upper end face of the chip base 2; the anode plate 4 is located at the middle position of the inner end face; the chip silicon wafer 5 is fixedly connected to the middle position of the upper end face of the anode plate 4; the cathode plate 6 is fixedly connected to the middle position of the upper end face of the chip silicon wafer 5; the chip gate 7 is fixedly connected to the inner side of the cathode plate 6; two groups of protective covers 11 are provided, and the two groups of protective covers 11 are respectively located at the front and rear end faces of the chip base 2; the chip mounting mechanism is arranged inside the chip base 2.

[0033] Among them, the chip mounting mechanism includes: a connection slot 201 and a connection plug 301; the connection slot 201 is opened on the inner side of the upper end face of the chip base 2; the connection plug 301 is fixedly connected to the lower end face of the chip cover 3, and the connection slot 201 and the connection plug 301 are plugged and connected. During use, when the chip cover 3 is installed on the upper end face of the chip base 2, the movement of the chip cover 3 drives the movement of the connection plug 301, and the connection plug 301 moves and inserts into the inside of the connection slot 201, and the chip cover 3 is fixedly installed on the upper end face of the chip base 2.

[0034] Among them, the chip mounting mechanism further includes: a mounting groove 8 and a thermal conductive silicone 9; the mounting groove 8 is opened at the middle position of the inner end face of the chip base 2, and the anode plate 4 is plugged and connected to the inside of the mounting groove 8; the thermal conductive silicone 9 is adhesively connected to the inner end face of the chip base 2 and the outer end face of the anode plate 4. During use, when the anode plate 4 is installed on the inner end face of the chip base 2, the anode plate 4 is placed into the inside of the mounting groove 8, and then the thermal conductive silicone 9 is used to fix the anode plate 4 on the inner end face of the chip base 2.

[0035] Among them, the chip mounting mechanism further includes: contact foot grooves 202 and chip contact feet 10; multiple groups of contact foot grooves 202 are provided, and the multiple groups of contact foot grooves 202 are respectively opened at the front and rear end faces of the chip base 2; multiple groups of chip contact feet 10 are provided, and the multiple groups of chip contact feet 10 are respectively fixedly connected to the front and rear end faces of the chip silicon wafer 5, and the multiple groups of chip contact feet 10 are respectively plugged and connected to the multiple groups of contact foot grooves 202, the outer sides of the multiple groups of chip contact feet 10 are located at the front and rear end faces of the chip base 2, and the multiple groups of chip contact feet 10 are respectively located at the inner end faces of the two groups of protective covers 11. During use, the chip contact feet 10 and the chip silicon wafer 5 are connected through the contact foot grooves 202.

[0036] Among them, the chip mounting mechanism further includes: positioning grooves 101 and positioning bumps 1001; there are four groups of positioning grooves 101 in total, and the four groups of positioning grooves 101 are respectively opened on the upper end surface of the mounting main board 1; there are four groups of positioning bumps 1001 in total, and the four groups of positioning bumps 1001 are respectively fixedly connected to the outer sides of the lower end surfaces of the four groups of chip pins 10. The four groups of positioning grooves 101 are respectively inserted and connected with the four groups of positioning bumps 1001. During use, when the chip pins 10 are connected to the upper end surface of the mounting main board 1, the movement of the chip pins 10 drives the movement of the positioning bumps 1001. The positioning bumps 1001 move out of the positioning grooves 101 on the upper end surface of the mounting main board 1, and the positioning bumps 1001 are inserted into the internal of the positioning grooves 101, so that the chip pins 10 can quickly find the mounting position on the mounting main board 1.

[0037] The specific usage method and function of the first embodiment: During the use of the present invention, when the chip cover 3 is installed on the upper end surface of the chip base 2, the movement of the chip cover 3 drives the movement of the connecting plug 301, and the connecting plug 301 moves and is inserted into the internal of the connecting slot 201. The chip cover 3 is fixedly installed on the upper end surface of the chip base 2. When the anode plate 4 is installed on the inner end surface of the chip base 2, the anode plate 4 is placed into the installation groove 8, and then the thermal conductive silicone 9 is used to fix the anode plate 4 on the inner end surface of the chip base 2. The chip pins 10 are connected to the chip silicon wafer 5 through the pin groove 202. When the chip pins 10 are connected to the upper end surface of the mounting main board 1, the movement of the chip pins 10 drives the movement of the positioning bumps 1001. The positioning bumps 1001 move out of the positioning grooves 101 on the upper end surface of the mounting main board 1, and the positioning bumps 1001 are inserted into the internal of the positioning grooves 101, so that the chip pins 10 can quickly find the mounting position on the mounting main board 1, realizing convenient connection when the chip is used.

[0038] Embodiment Two:

[0039] On the basis of the first embodiment, please refer to Figures 6 to 8 as shown:

[0040] The present invention provides a square thyristor chip, which further includes a chip protection mechanism. There are two groups of chip protection mechanisms in total, and the two groups of chip protection mechanisms are respectively arranged on the front and rear end surfaces of the chip base 2. The chip protection mechanism includes: protection slots 203 and protection plugs 12; there are two groups of protection slots 203 in total, and the two groups of protection slots 203 are respectively opened on the left and right sides of the outer end surface of the chip base 2; there are two groups of protection plugs 12 in total, and the two groups of protection plugs 12 are respectively fixedly connected to the left and right sides of the inner end surface of the protection cover 11. The two groups of protection slots 203 are respectively inserted and connected with the two groups of protection plugs 12. During use, when the protection cover 11 is installed on the outer end surface of the chip base 2, the movement of the protection cover 11 drives the movement of the protection plug 12, and the protection plug 12 moves into the internal of the protection slot 203, and the protection plug 12 is inserted into the internal of the protection slot 203.

[0041] Among them, the chip protection mechanism also includes: a stabilizing slot 1201 and a stabilizing plug 13; the stabilizing slot 1201 is opened on the outer end face of a group of protection plugs 12 on the right side; the stabilizing plug 13 is slidably connected to the inside of the outer end face of the chip base 2, and the stabilizing slot 1201 and the stabilizing plug 13 are plug-connected. During use, when the protection plug 12 is inserted into the protection slot 203, it drives the stabilizing slot 1201 to slide into the protection slot 203, and the stabilizing slot 1201 slides to the position of the stabilizing plug 13.

[0042] Among them, the chip protection mechanism also includes: a stabilizing block 14 and a stabilizing spring 1401; the stabilizing block 14 is slidably connected to the inside of the outer end surface of the chip base 2, the stabilizing block 14 slides on the outer end surface, and the stabilizing plug 13 is fixedly connected to the stabilizing block 14; the stabilizing spring 1401 is fixedly connected to the inside of the outer end surface of the chip base 2, and the stabilizing block 14 and the stabilizing spring 1401 are elastically connected. During use, the elastic force of the stabilizing spring 1401 drives the stabilizing block 14 to slide, and the staff can also drive the stabilizing block 14 to slide. When the stabilizing block 14 slides, it drives the stabilizing plug 13 to slide. The stabilizing plug 13 can slide and be inserted into the stabilizing slot 1201 to fix the protective cover 11 on the outer end surface of the chip base 2. The protective cover 11 can also be disassembled on the outer end surface of the chip base 2.

[0043] Among them, the chip protection mechanism also includes: a bottom slider 15 and a bottom spring 1501; there are two groups of bottom sliders 15, and the two groups of bottom sliders 15 are respectively slidably connected to the left and right sides of the lower end surface of the protective shield 11, and the two groups of bottom sliders 15 slide on the left and right sides of the lower end surface of the protective shield 11; there are two groups of bottom springs 1501, and the two groups of bottom springs 1501 are respectively fixedly connected to the left and right sides of the inside of the protective shield 11, and the two groups of bottom springs 1501 are respectively elastically connected to the upper end surfaces of the two groups of bottom sliders 15. During use, the elastic force of the bottom spring 1501 drives the bottom slider 15 to slide, and the bottom slider 15 slides to the outside of the lower end surface of the protective shield 11, and the bottom slider 15 protects the chip contact pins 10 inside the protective shield 11.

[0044] Specific usage and function of the second embodiment: During the use of the present invention, when the protective shield 11 is installed on the outer end surface of the chip base 2, the movement of the protective shield 11 drives the protective plug 12 to move, and the protective plug 12 moves to the inside of the protective slot 203, and the protective plug 12 is inserted into the inside of the protective slot 203. When the protective plug 12 is inserted into the inside of the protective slot 203, it drives the stabilizing slot 1201 to slide into the inside of the protective slot 203, and the stabilizing slot 1201 slides to the position of the stabilizing plug 13, and the elastic force of the stabilizing spring 1401 drives the stabilizing block 14 to slide, and the staff can also bend the stabilizing block 14 to move. The block 14 slides, and when the stable block 14 slides, it drives the stable plug block 13 to slide. The stable plug block 13 can slide and be inserted into the stable slot 1201 to fix the protective cover 11 on the outer end surface of the chip base 2. The protective cover 11 can also be removed on the outer end surface of the chip base 2. The elastic force of the bottom spring 1501 drives the bottom slider 15 to slide. The bottom slider 15 slides to the outside of the lower end surface of the protective cover 11. The bottom slider 15 protects the chip contact pins 10 inside the protective cover 11, so as to protect the chip contact pins 10 on the chip and avoid deformation caused by impact during transportation that affects the use.

Claims

1. A square thyristor chip, comprising: A main board (1), a chip base (2), a chip cover (3), an anode sheet (4), a chip silicon wafer (5), a cathode sheet (6), a chip gate electrode (7), a protective shield (11), a chip mounting mechanism and a chip protection mechanism are installed; the chip base (2) is located on the upper end surface of the main board (1); the chip cover (3) is located in the middle of the upper end surface of the chip base (2); the anode sheet (4) is located in the middle of the inner end surface; the chip silicon wafer (5) is fixedly connected to the middle of the upper end surface of the anode sheet (4); the cathode sheet (6) is fixedly connected to the middle of the upper end surface of the chip silicon wafer (5); the chip gate electrode (7) is fixedly connected to the inner side of the cathode sheet (6); two groups of protective shields (11) are provided, and the two groups of protective shields (11) are respectively provided on the front and rear end surfaces of the chip base (2); the chip mounting mechanism is provided inside the chip base (2); two groups of chip protection mechanisms are provided, and the two groups of chip protection mechanisms are respectively provided on the front and rear end surfaces of the chip base (2); The chip protection mechanism comprises: a protection slot (203) and a protection plug-in block (12); the protection slot (203) is provided in two groups, and the two groups of protection slots (203) are respectively opened on the left and right sides of the outer end surface of the chip base (2); the protection plug-in block (12) is provided in two groups, and the two groups of protection plug-in blocks (12) are respectively fixedly connected to the left and right sides of the inner end surface of the protection shield (11), and the two groups of protection slots (203) are respectively plugged and connected to the two groups of protection plug-in blocks (12).

2. A square thyristor chip as claimed in claim 1, characterized in that: The chip installation mechanism comprises: a connection slot (201) and a connection plug-in block (301); the connection slot (201) is arranged on the inner side of the upper end surface of the chip base (2); the connection plug-in block (301) is fixedly connected to the lower end surface of the chip protection cover (3), and the connection slot (201) and the connection plug-in block (301) are plug-connected.

3. A square thyristor chip as claimed in claim 1, characterized in that: The chip mounting mechanism further comprises: a mounting groove (8) and a heat-conducting silica gel (9); the mounting groove (8) is provided in the middle of the inner end surface of the chip base (2), and the anode sheet (4) is plugged and connected to the inside of the mounting groove (8); the heat-conducting silica gel (9) is adhesively connected to the inner end surface of the chip base (2) and the outer end surface of the anode sheet (4).

4. A square thyristor chip as claimed in claim 1, characterized in that: The chip mounting mechanism further comprises: contact pin grooves (202) and chip contact pins (10); the contact pin grooves (202) are provided in a plurality of groups, and the plurality of groups of contact pin grooves (202) are respectively opened on the front and rear end surfaces of the chip base (2); the chip contact pins (10) are provided in a plurality of groups, and the plurality of groups of chip contact pins (10) are respectively fixedly connected to the front and rear end surfaces of the chip silicon wafer (5), and the plurality of groups of chip contact pins (10) are respectively plug-connected to the plurality of groups of contact pin grooves (202), and the outer sides of the plurality of groups of chip contact pins (10) are located on the front and rear end surfaces of the chip base (2), and the plurality of groups of chip contact pins (10) are respectively located on the inner end surfaces of the two groups of protective shields (11).

5. A square thyristor chip as claimed in claim 4, characterized in that: The chip mounting mechanism further comprises: positioning grooves (101) and positioning protrusions (1001); the positioning grooves (101) are provided in four groups, and the four groups of positioning grooves (101) are respectively opened on the upper end surface of the mounting mainboard (1); the positioning protrusions (1001) are provided in four groups, and the four groups of positioning protrusions (1001) are respectively fixedly connected to the outer sides of the lower end surfaces of the four groups of chip contact pins (10), and the four groups of positioning grooves (101) are respectively plug-connected to the four groups of positioning protrusions (1001).

6. A square thyristor chip as claimed in claim 1, characterized in that: The chip protection mechanism further comprises: a stabilizing slot (1201) and a stabilizing plug-in block (13); the stabilizing slot (1201) is provided on the outer end surface of a group of protection plug-ins (12) on the right side; the stabilizing plug-in block (13) is slidably connected inside the outer end surface of the chip base (2), and the stabilizing slot (1201) and the stabilizing plug-in block (13) are plug-connected.

7. A square thyristor chip as claimed in claim 6, characterized in that: The chip protection mechanism also includes: a stabilizing block (14) and a stabilizing spring (1401); the stabilizing block (14) is slidably connected to the inside of the outer end surface of the chip base (2), the stabilizing block (14) slides on the outer end surface, and the stabilizing plug (13) and the stabilizing block (14) are fixedly connected; the stabilizing spring (1401) is fixedly connected to the inside of the outer end surface of the chip base (2), and the stabilizing block (14) and the stabilizing spring (1401) are elastically connected.

8. A square thyristor chip as claimed in claim 1, characterized in that: The chip protection mechanism further comprises: a bottom slider (15) and a bottom spring (1501); the bottom slider (15) is provided in two groups, the two groups of bottom sliders (15) are respectively slidably connected to the left and right sides of the lower end surface of the protective shield (11), and the two groups of bottom sliders (15) are respectively slidable on the left and right sides of the lower end surface of the protective shield (11); the bottom spring (1501) is provided in two groups, the two groups of bottom springs (1501) are respectively fixedly connected to the left and right sides of the inside of the protective shield (11), and the two groups of bottom springs (1501) are respectively elastically connected to the upper end surfaces of the two groups of bottom sliders (15).

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