阅读说明：本技术 一种具有过热保护功能的机顶盒 (Set-top box with overheat protection function ) 是由 李彩华 于 2020-05-08 设计创作，主要内容包括：本发明涉及一种具有过热保护功能的机顶盒,包括主体、保护机构、两个除杂机构、两个进气管、两个滤网和四个支脚,所述保护机构包括固定盒、连接管、弹簧、气筒、降温组件、两个活塞、两个连接组件和两个控制组件,所述降温组件包括电池、电缆、两个制冷棒和两个启闭单元,所述除杂机构包括第一轴承、转轴、第一锥齿轮和第二锥齿轮,该具有过热保护功能的机顶盒通过保护机构,实现了过热保护的功能,防止主体内过热而损坏设备,提高了设备的安全性,通过除杂机构,带动滤网转动,通过离心力,可以使得粘附在滤网的灰尘被甩出,从而实现了除杂的功能,减小了滤网堵塞的几率,提高了设备的实用性。(The invention relates to a set top box with an overheating protection function, which comprises a main body, a protection mechanism, two impurity removing mechanisms, two air inlet pipes, two filter screens and four support legs, wherein the protection mechanism comprises a fixed box, a connecting pipe, a spring, an air cylinder, a cooling assembly, two pistons, two connecting assemblies and two control assemblies, the cooling assembly comprises a battery, a cable, two refrigeration rods and two opening and closing units, the impurity removing mechanism comprises a first bearing, a rotating shaft, a first bevel gear and a second bevel gear, the set top box with the overheating protection function realizes the overheating protection function through the protection mechanism, prevents the equipment from being damaged due to overheating in the main body, improves the safety of the equipment, drives the filter screens to rotate through the impurity removing mechanism, can throw out dust adhered to the filter screens through centrifugal force, thereby realizing the impurity removing function and reducing the probability of blocking of the filter screens, the practicability of the equipment is improved.)

1. The set top box with the overheat protection function is characterized by comprising a main body (1), a protection mechanism, two impurity removing mechanisms, two air inlet pipes (4), two filter screens (3) and four support legs (2), wherein the four support legs (2) are respectively fixed at four corners below the main body (1), one ends of the two air inlet pipes (4) are respectively communicated with two sides of the main body (1), the filter screens (3) are in one-to-one correspondence with the air inlet pipes (4), the filter screens (3) abut against the other ends of the air inlet pipes (4), the impurity removing mechanisms are in one-to-one correspondence with the filter screens (3), the impurity removing mechanisms are connected with the filter screens (3), the protection mechanism is arranged in the main body (1), the protection mechanism is connected with the impurity removing mechanisms, and a PLC is arranged in the main body (1);

the protection mechanism comprises a fixed box (5), a connecting pipe (6), a spring (9), an air cylinder (7), a cooling assembly, two pistons (8), two connecting assemblies and two control assemblies, wherein the fixed box (5) is fixed in the main body (1), the air cylinder (7) is fixed above the main body (1), the lower part of the air cylinder (7) is communicated with the fixed box (5) through the connecting pipe (6), the two pistons (8) are respectively arranged at two sides in the air cylinder (7), the pistons (8) are connected with the inner wall of the air cylinder (7) in a sealing manner, two ends of the spring (9) are respectively connected with the two pistons (8), the connecting assemblies are arranged above the main body (1), the pistons (8) are in one-to-one correspondence with the connecting assemblies, the pistons (8) are connected with the connecting assemblies, small holes are arranged at two sides of the air cylinder (7), the connecting assemblies correspond to the small holes one by one, the cooling assemblies and the control assemblies are arranged inside the main body (1), the two control assemblies are respectively arranged on two sides in the main body (1), the control assemblies correspond to the impurity removing mechanisms one by one, and the control assemblies are connected with the impurity removing mechanisms;

the cooling assembly comprises a battery (22), a cable (21), two refrigeration rods (20) and two opening and closing units, wherein the battery (22) is fixed at the top in the main body (1), the two refrigeration rods (20) are respectively fixed on two sides in the main body (1), one ends of the two refrigeration rods (20) are connected through the cable (21), the refrigeration rods (20) correspond to the opening and closing units one by one, the opening and closing units comprise two metal sheets (19), the other ends of the refrigeration rods (20) are connected with one metal sheet (19) through the cable (21), the other metal sheet (19) is connected with one end of the battery (22) through the cable (21), and the two metal sheets (19) are arranged oppositely;

the impurity removing mechanism comprises a first bearing, a rotating shaft (26), a first bevel gear (25) and a second bevel gear (24), the first bearing is fixed inside the air inlet pipe (4), one end of the rotating shaft (26) is fixedly connected with the filter screen (3), the other end of the rotating shaft (26) is fixedly connected with the first bevel gear (25), the second bevel gear (24) is connected with the control component, the first bevel gear (25) is meshed with the second bevel gear (24), and the rotating shaft (26) is fixedly connected with an inner ring of the first bearing.

2. The set top box with the overheat protection function according to claim 1, wherein the connecting assembly comprises a connecting rod (10), a screw rod (12), a ball screw bearing (11), a worm (13) and two second bearings, the second bearings are fixed above the main body (1), one end of the screw rod (12) and one end of the worm (13) are respectively and fixedly connected with inner rings of the two second bearings, the other end of the screw rod (12) is fixedly connected with the other end of the worm (13), the ball screw bearing (11) is sleeved on the screw rod (12), a joint of the ball screw bearing (11) and the screw rod (12) is provided with a thread matched with the screw rod (12), the connecting rod (10) is L-shaped, one end of the connecting rod (10) is fixedly connected with one side of the piston (8) close to the small hole, and the other end of the connecting rod (10) passes through the small hole and is fixedly connected with an outer ring of the ball screw bearing (11), the connecting rod (10) is matched with the small hole, and the worm (13) is connected with the control assembly.

3. The set top box with the overheat protection function according to claim 2, wherein the control assembly comprises a worm wheel (14), a connecting shaft (15), a third bearing, a connecting gear (16), a connecting rack (17) and a conducting strip (18), the third bearing is fixed on the top inside the main body (1), two round holes are arranged above the main body (1), the round holes correspond to the connecting shaft (15) one by one, one end of the connecting shaft (15) is fixedly connected with the worm wheel (14), the worm wheel (14) is engaged with the worm (13), the other end of the connecting shaft (15) passes through the round holes and is arranged inside the main body (1), the other end of the connecting shaft (15) is fixedly connected with a second bevel gear (24), the connecting gear (16) is fixed on the connecting shaft (15), the connecting rack (17) is arranged on one side of the connecting gear (16), the conducting strip (18) is fixedly connected with one end, close to the metal sheet (19), of the connecting rack (17), and the length of the conducting strip (18) is larger than the distance between the two metal sheets (19).

4. The set top box with the overheat protection function according to claim 3, wherein the control assembly further comprises two guide blocks (23), the two guide blocks (23) are respectively disposed above and below the connecting rack (17), one side of the guide block (23) is fixedly connected with the inner wall of the main body (1), grooves are respectively disposed above and below the connecting rack (17), the grooves correspond to the guide blocks (23) one by one, the guide blocks (23) are disposed inside the grooves, the guide blocks (23) are matched with the grooves, and the guide blocks (23) are slidably connected with the grooves.

5. The set top box with overheat protection function according to claim 4, wherein said groove is a dovetail groove.

6. The set-top box with the overheat protection function according to claim 1, wherein a recess is uniformly formed on one side of the filter screen (3) close to the air inlet pipe (4), a ball (28) is arranged in the recess, the center of the ball (28) is arranged inside the recess, an annular groove is formed on one side of the air inlet pipe (4) close to the filter screen (3), and the ball (28) abuts against the inner wall of the annular groove.

7. The set top box with the overheat protection function according to claim 1, wherein the trash removing mechanism further comprises a plurality of paddles (27), and the paddles (27) are circumferentially and uniformly fixed on the rotating shaft (26).

8. The set top box with the overheat protection function according to claim 2, wherein the lead screw (12) and the worm (13) are coated with an anti-corrosion zinc coating.

9. A set-top box with overheat protection function according to claim 3, wherein said connecting gear (16) is coated with grease.

10. A set-top box having an overheat protection function as claimed in claim 1, wherein said small hole has a square cross-sectional shape.

Technical Field

The invention relates to the field of set-top boxes, in particular to a set-top box with an overheat protection function.

Background

A digital video converter Box (Set Top Box), abbreviated STB, is a device that connects a television Set to an external signal source, commonly referred to as a Set-Top Box or Set-Top Box. It can convert the compressed digital signal into television content and display it on the television. The signals may come from cable, satellite dish, broadband network and terrestrial broadcast. The set-top box receives digital content, including electronic program guides, internet web pages, etc., in addition to the images and sounds that an analog television can provide. It enables users to watch digital television programs on existing television sets and to conduct interactive digital entertainment, education and commercialization activities over a network.

After the existing set top box works for a long time, the temperature of the set top box can be caused to be too high, so that earphones damaged by overheating of the set top box are increased, the service life of the existing set top box is influenced, and moreover, after the existing set top box works for a long time, dust in air can block a heat dissipation port of the existing set top box, so that the circulation of air inside and outside the set top box is not smooth, the heat dissipation effect is influenced, and the practicability of the existing set top box is greatly reduced.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: in order to overcome the defects of the prior art, a set top box with an overheat protection function is provided.

The technical scheme adopted by the invention for solving the technical problems is as follows: a set top box with an overheating protection function comprises a main body, a protection mechanism, two impurity removal mechanisms, two air inlet pipes, two filter screens and four support legs, wherein the four support legs are fixed at four corners below the main body respectively;

the protection mechanism includes fixed box, connecting pipe, spring, inflator, cooling subassembly, two pistons, two coupling assembling and two control assembly, fixed box is fixed in the inside of main part, the inflator is fixed in the top of main part, the below of inflator passes through connecting pipe and fixed box intercommunication, and two pistons set up the both sides in the inflator respectively, the inner wall sealing connection of piston and inflator, the both ends of spring are connected with two pistons respectively, coupling assembling sets up the top at the main part, piston and coupling assembling one-to-one, the piston is connected with coupling assembling, the both sides of inflator all are equipped with the aperture, coupling assembling and aperture one-to-one, cooling subassembly and control assembly all set up in the inside of main part, and two control assembly set up the both sides in the main part respectively, control assembly and edulcoration mechanism one-to-one, the control assembly is connected with the impurity removing mechanism;

the cooling assembly comprises a battery, a cable, two refrigeration rods and two opening and closing units, the battery is fixed at the top in the main body, the two refrigeration rods are respectively fixed at two sides in the main body, one ends of the two refrigeration rods are connected through the cable, the refrigeration rods correspond to the opening and closing units one by one, the opening and closing units comprise two metal sheets, the other ends of the refrigeration rods are connected with one metal sheet through the cable, the other metal sheet is connected with one end of the battery through the cable, and the two metal sheets are arranged oppositely;

the impurity removing mechanism comprises a first bearing, a rotating shaft, a first bevel gear and a second bevel gear, the first bearing is fixed inside the air inlet pipe, one end of the rotating shaft is fixedly connected with the filter screen, the other end of the rotating shaft is fixedly connected with the first bevel gear, the second bevel gear is connected with the control assembly, the first bevel gear is meshed with the second bevel gear, and the rotating shaft is fixedly connected with an inner ring of the first bearing.

Preferably, in order to transmit power, the connecting assembly comprises a connecting rod, a screw rod, two ball screw bearings, a worm and two second bearings, the second bearings are fixed above the main body, one end of the screw rod and one end of the worm are respectively fixedly connected with inner rings of the two second bearings, the other end of the screw rod is fixedly connected with the other end of the worm, the ball screw bearings are sleeved on the screw rod, threads matched with the screw rod are arranged at the connecting part of the ball screw bearings and the screw rod, the connecting rod is L-shaped, one end of the connecting rod is fixedly connected with one side, close to the small hole, of the piston, the other end of the connecting rod penetrates through the small hole and is fixedly connected with the outer rings of the ball screw bearings, the connecting rod is matched with the small hole, and the.

As preferred, for control refrigeration stick work, control assembly includes worm wheel, connecting axle, third bearing, connecting gear, connecting rack and conducting strip, the top in the main part is fixed to the third bearing, the top of main part is equipped with two round holes, round hole and connecting axle one-to-one, the one end and the worm wheel fixed connection of connecting axle, worm wheel and worm meshing, the other end of connecting axle passes the round hole and sets up the inside at the main part, the other end and the second bevel gear fixed connection of connecting axle, connecting gear fixes on the connecting axle, connecting rack sets up the one side at connecting gear, the conducting strip is with the one end fixed connection who is close to the sheetmetal of connecting rack, the length of conducting strip is greater than the distance between two sheetmetals.

Preferably, in order to restrict the moving direction of the connecting rack, the control assembly further comprises two guide blocks, the two guide blocks are arranged above and below the connecting rack respectively, one side of each guide block is fixedly connected with the inner wall of the main body, grooves are formed in the upper portion and the lower portion of the connecting rack, the grooves correspond to the guide blocks one to one, the guide blocks are arranged inside the grooves and matched with the grooves, and the guide blocks are connected with the grooves in a sliding mode.

Preferably, in order to prevent the guide block from being separated from the groove, the groove is a dovetail groove.

Preferably, in order to reduce wear, one side of the filter screen close to the air inlet pipe is uniformly provided with a notch, a ball is arranged in the notch, the center of the ball is arranged in the notch, one side of the air inlet pipe close to the filter screen is provided with an annular groove, and the ball is abutted to the inner wall of the annular groove.

Preferably, in order to accelerate the air inlet speed, the impurity removing mechanism further comprises a plurality of paddles, and the paddles are circumferentially and uniformly fixed on the rotating shaft.

Preferably, in order to prolong the service life of the screw rod and the worm, the screw rod and the worm are coated with anti-corrosion zinc coatings.

Preferably, the connecting gear is coated with grease in order to make the connecting rack move smoothly.

Preferably, the cross-sectional shape of the small hole is square in order to limit the moving direction of the connecting rod.

The invention has the advantages that the set-top box with the overheat protection function realizes the overheat protection function through the protection mechanism, prevents the equipment from being damaged due to overheating in the main body, improves the safety of the equipment, has strong anti-jamming capability and improves the reliability of the equipment by detecting the temperature change through the principle of expansion with heat and contraction with cold instead of detecting the temperature change through an electronic element compared with the prior protection mechanism, drives the filter screen to rotate through the impurity removal mechanism, can throw out dust adhered to the filter screen through centrifugal force, thereby realizing the impurity removal function, reducing the probability of the blockage of the filter screen, improving the practicability of the equipment, and compared with the prior impurity removal mechanism, the impurity removal mechanism and the protection mechanism are an integrated linkage mechanism, can realize the impurity removal function while realizing the overheat protection, and does not need electric power driving, thereby leading the equipment to be more energy-saving, the environmental protection of the equipment is improved.

Drawings

The invention is further illustrated with reference to the following figures and examples.

FIG. 1 is a schematic diagram of a set-top box with overheat protection according to the present invention;

FIG. 2 is an enlarged view of portion A of FIG. 1;

FIG. 3 is a schematic view of the connection structure of the connecting rack and the guide block of the set-top box with overheat protection function according to the present invention;

FIG. 4 is an enlarged view of portion B of FIG. 1;

in the figure: 1. the refrigerator comprises a main body, a support leg, a filter screen, an air inlet pipe, a fixing box, a connecting pipe, a gas cylinder, a piston, a spring, a connecting rod, a ball screw bearing, a screw rod, a worm gear, a worm wheel, a worm gear, a connecting shaft, a connecting gear 17, a connecting rack, a conducting strip 18, a metal sheet, a refrigerating rod 20, a cable 21, a battery 22, a guide block 23, a second bevel gear 24, a first bevel gear 25, a rotating shaft 26, a blade 27 and a ball 28.

Detailed Description

The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic views illustrating only the basic structure of the present invention in a schematic manner, and thus show only the constitution related to the present invention.

As shown in fig. 1, a set top box with an overheat protection function comprises a main body 1, a protection mechanism, two impurity removal mechanisms, two air inlet pipes 4, two filter screens 3 and four support legs 2, wherein the four support legs 2 are respectively fixed at four corners below the main body 1, one ends of the two air inlet pipes 4 are respectively communicated with two sides of the main body 1, the filter screens 3 are in one-to-one correspondence with the air inlet pipes 4, the filter screens 3 abut against the other ends of the air inlet pipes 4, the impurity removal mechanisms are in one-to-one correspondence with the filter screens 3, the impurity removal mechanisms are connected with the filter screens 3, the protection mechanism is arranged in the main body 1, the protection mechanism is connected with the impurity removal mechanisms;

a PLC, i.e., a programmable logic controller, which employs a programmable memory for storing therein a program, executing instructions for user-oriented operations such as logic operation, sequence control, timing, counting, and arithmetic operation, and controlling various types of machines or production processes through digital or analog input/output, is essentially a computer dedicated for industrial control, has a hardware structure substantially the same as that of a microcomputer, and is generally used for data processing and instruction reception and output for realizing central control.

This STB with overheat protection function passes through protection mechanism, has realized overheat protection's function, prevents in the main part 1 overheated and damage equipment, has improved the security of equipment, through edulcoration mechanism, drives filter screen 3 and rotates, through centrifugal force, can be so that the adhesion is thrown away at the dust of filter screen 3 to realized the function of edulcoration, reduced the probability that filter screen 3 blockked up, improved the practicality of equipment.

As shown in fig. 1-2, the protection mechanism comprises a fixing box 5, a connecting pipe 6, a spring 9, an inflator 7, a cooling component, two pistons 8, two connecting components and two control components, the fixing box 5 is fixed in the main body 1, the inflator 7 is fixed above the main body 1, the lower part of the inflator 7 is communicated with the fixing box 5 through the connecting pipe 6, the two pistons 8 are respectively arranged at two sides in the inflator 7, the inner wall sealing connection of the pistons 8 and the inflator 7 is realized, two ends of the spring 9 are respectively connected with the two pistons 8, the connecting components are arranged above the main body 1, the pistons 8 are in one-to-one correspondence with the connecting components, the pistons 8 are connected with the connecting components, both sides of the inflator 7 are respectively provided with small holes, the connecting components are in one-to-one correspondence with the small holes, the cooling component and the control components are both arranged in, the two control assemblies are respectively arranged on two sides in the main body 1, the control assemblies correspond to the impurity removing mechanisms one by one, and the control assemblies are connected with the impurity removing mechanisms;

the cooling assembly comprises a battery 22, a cable 21, two refrigeration rods 20 and two opening and closing units, the battery 22 is fixed at the top in the main body 1, the two refrigeration rods 20 are respectively fixed at two sides in the main body 1, one ends of the two refrigeration rods 20 are connected through the cable 21, the refrigeration rods 20 correspond to the opening and closing units one by one, each opening and closing unit comprises two metal sheets 19, the other end of each refrigeration rod 20 is connected with one metal sheet 19 through the cable 21, the other metal sheet 19 is connected with one end of the battery 22 through the cable 21, and the two metal sheets 19 are arranged oppositely;

temperature rise in main part 1, lead to temperature rise in the fixed box 5, principle through expend with heat and contract with cold, make the air expansion in the fixed box 5, thereby make two pistons 8 remove to the direction of keeping away from each other, extension spring 9, make coupling assembling work, drive control assembly work, make edulcoration mechanism work, realize the function of edulcoration, when temperature lasts to increase in main part 1, make control assembly's displacement increase, when control assembly supports with sheetmetal 19 and leans on, show overheat in the main part 1, battery 22 and two refrigeration sticks 20 form a return circuit simultaneously, make refrigeration stick 20 work, carry out rapid cooling work in to main part 1, thereby realized overheat protection's function, prevent overheat and damage equipment in the main part 1, the reliability of equipment has been improved.

As shown in fig. 1, the impurity removing mechanism includes a first bearing, a rotating shaft 26, a first bevel gear 25 and a second bevel gear 24, the first bearing is fixed inside the air inlet pipe 4, one end of the rotating shaft 26 is fixedly connected with the filter screen 3, the other end of the rotating shaft 26 is fixedly connected with the first bevel gear 25, the second bevel gear 24 is connected with the control component, the first bevel gear 25 is engaged with the second bevel gear 24, and the rotating shaft 26 is fixedly connected with an inner ring of the first bearing.

The control assembly during operation drives second bevel gear 24 and rotates, through first bevel gear 25 and the meshing of second bevel gear 24 for pivot 26 rotates, thereby can drive filter screen 3 and rotate, through the centrifugal force of filter screen 3, can make the adhesion be thrown away at the dust of filter screen 3, thereby has realized the function of edulcoration, has reduced the probability that filter screen 3 blockked up, has improved the practicality of equipment.

Preferably, in order to transmit power, the connecting assembly includes a connecting rod 10, a screw rod 12, a ball screw bearing 11, a worm 13 and two second bearings, the second bearings are fixed above the main body 1, one end of the screw rod 12 and one end of the worm 13 are respectively and fixedly connected with inner rings of the two second bearings, the other end of the screw rod 12 is fixedly connected with the other end of the worm 13, the ball screw bearing 11 is sleeved on the screw rod 12, a thread matched with the screw rod 12 is arranged at a joint of the ball screw bearing 11 and the screw rod 12, the connecting rod 10 is in an L shape, one end of the connecting rod 10 is fixedly connected with one side of the piston 8 close to the small hole, the other end of the connecting rod 10 penetrates through the small hole to be fixedly connected with an outer ring of the ball screw bearing 11, the connecting rod 10 is matched with the small hole, and the.

Preferably, in order to control the operation of the refrigeration stick 20, the control assembly comprises a worm wheel 14, a connecting shaft 15, a third bearing, a connecting gear 16, a connecting rack 17 and a conducting strip 18, the third bearing is fixed at the top in the main body 1, two round holes are arranged above the main body 1, the round holes correspond to the connecting shafts 15 one by one, one end of each connecting shaft 15 is fixedly connected with the worm wheel 14, the worm wheel 14 is meshed with the worm 13, the other end of the connecting shaft 15 passes through the round hole and is arranged inside the main body 1, the other end of the connecting shaft 15 is fixedly connected with a second bevel gear 24, the connecting gear 16 is fixed on the connecting shaft 15, the connecting rack 17 is arranged on one side of the connecting gear 16, the conducting strip 18 is fixedly connected with one end of the connecting rack 17 close to the metal sheet 19, and the length of the conducting strip 18 is greater than the distance between the two metal sheets 19.

When the temperature in the main body 1 rises, the temperature in the fixed box 5 rises, the air in the fixed box 5 expands through the principle of expansion with heat and contraction with cold, so that the two pistons 8 move towards the directions away from each other, the extension spring 9 drives the screw rod 12 to move through the connecting rod 10, so that the screw rod 12 rotates, so as to drive the worm 13 to rotate, the connecting shaft 15 rotates through the meshing of the worm 13 and the worm wheel 14, so as to drive the second bevel gear 24 to rotate, the rotating shaft 26 rotates through the meshing of the first bevel gear 25 and the second bevel gear 24, so as to drive the filter screen 3 to rotate, the dust adhered to the filter screen 3 can be thrown out through the centrifugal force of the filter screen 3, so that the function of impurity removal is realized, the probability of blockage of the filter screen 3 is reduced, the practicability of the equipment is improved, and when the connecting shaft 15 rotates, the connecting gear 16 can, through the meshing of connecting gear 16 with connecting rack 17, make connecting rack 17 to the direction removal near sheetmetal 19, thereby drive conducting strip 18 to the direction removal near sheetmetal 19, when the temperature lasts to increase in main part 1, make connecting rack 17's displacement increase, when sheetmetal 19 supports with conducting strip 18 and leans on, show overheated in the main part 1, battery 22 and two refrigeration stick 20 form a return circuit simultaneously, make refrigeration stick 20 work, carry out rapid cooling work in to main part 1, thereby realized overheat protection's function, prevent overheated and damage equipment in the main part 1, the reliability of equipment has been improved.

As shown in fig. 3, the control assembly further includes two guide blocks 23, the two guide blocks 23 are respectively disposed above and below the connecting rack 17, one side of the guide block 23 is fixedly connected with the inner wall of the main body 1, grooves are disposed above and below the connecting rack 17, the grooves correspond to the guide blocks 23 one to one, the guide blocks 23 are disposed inside the grooves, the guide blocks 23 are matched with the grooves, and the guide blocks 23 are slidably connected with the grooves.

Preferably, the groove is a dovetail groove in order to prevent the guide block 23 from being disengaged from the groove.

When the connecting rack 17 moves, the guide block 23 is embedded in the groove of the connecting rack 17, so that the connecting rack 17 moves along the guide block 23, the moving direction of the connecting rack 17 is limited, and the connecting rack 17 is prevented from inclining to influence the meshing of the connecting rack 17 and the connecting gear 16.

As shown in fig. 4, one side of the filter screen 3 close to the air inlet pipe 4 is uniformly provided with a notch, a ball 28 is arranged in the notch, the center of the ball 28 is arranged in the notch, one side of the air inlet pipe 4 close to the filter screen 3 is provided with an annular groove, and the ball 28 abuts against the inner wall of the annular groove.

Through setting up ball 28, reduced the frictional force between filter screen 3 and the intake pipe 4 for filter screen 3 rotates smoothly, thereby has reduced the wearing and tearing of filter screen 3, has prolonged the life of filter screen 3.

Preferably, in order to accelerate the air inlet speed, the impurity removing mechanism further comprises a plurality of paddles 27, and the paddles 27 are circumferentially and uniformly fixed on the rotating shaft 26.

When the rotating shaft 26 rotates, the paddle 27 can be driven to rotate, so that air pressure in the air inlet pipe 4 is reduced, external air is convenient to enter the air inlet pipe 4 through the filter screen 3, and the air circulation speed inside and outside the main body 1 is increased.

Preferably, in order to prolong the service life of the screw rod 12 and the worm 13, the screw rod 12 and the worm 13 are coated with an anti-corrosion zinc coating.

Preferably, in order to make the linking rack 17 move smoothly, the linking gear 16 is coated with grease, so that the friction between the linking rack 17 and the linking gear 16 is reduced, thereby making the linking rack 17 move more smoothly.

Preferably, the cross-sectional shape of the small hole is square in order to limit the moving direction of the connecting rod 10.

Through setting up the aperture into the quad slit for connecting rod 10 can not take place to rotate when removing, thereby stability when having improved connecting rod 10 and removing, thereby takes place to rock when preventing that ball bearing 11 from removing along lead screw 12.

When the temperature in the main body 1 rises, the temperature in the fixed box 5 rises, the air in the fixed box 5 expands through the principle of expansion with heat and contraction with cold, so that the two pistons 8 move towards the directions away from each other, the extension spring 9 drives the screw rod 12 to move through the connecting rod 10, so that the screw rod 12 rotates, so as to drive the worm 13 to rotate, the connecting shaft 15 rotates through the meshing of the worm 13 and the worm wheel 14, so as to drive the second bevel gear 24 to rotate, the rotating shaft 26 rotates through the meshing of the first bevel gear 25 and the second bevel gear 24, so as to drive the filter screen 3 to rotate, the dust adhered to the filter screen 3 can be thrown out through the centrifugal force of the filter screen 3, so that the function of impurity removal is realized, the probability of blockage of the filter screen 3 is reduced, the practicability of the equipment is improved, and when the connecting shaft 15 rotates, the connecting gear 16 can, through the meshing of connecting gear 16 with connecting rack 17, make connecting rack 17 to the direction removal near sheetmetal 19, thereby drive conducting strip 18 to the direction removal near sheetmetal 19, when the temperature lasts to increase in main part 1, make connecting rack 17's displacement increase, when sheetmetal 19 supports with conducting strip 18 and leans on, show overheated in the main part 1, battery 22 and two refrigeration stick 20 form a return circuit simultaneously, make refrigeration stick 20 work, carry out rapid cooling work in to main part 1, thereby realized overheat protection's function, prevent overheated and damage equipment in the main part 1, the reliability of equipment has been improved.

Compared with the prior art, the set top box with the overheat protection function realizes the overheat protection function through the protection mechanism, prevents the main body 1 from being damaged by overheat, improves the safety of the equipment, has strong anti-jamming capability and improves the reliability of the equipment by detecting temperature change through the principle of expansion with heat and contraction with cold instead of detecting temperature change by an electronic element through an impurity removing mechanism which drives the filter screen 3 to rotate, can lead dust adhered to the filter screen 3 to be thrown out through centrifugal force, thereby realizing the impurity removing function, reducing the blocking probability of the filter screen 3, improving the practicability of the equipment, and compared with the prior impurity removing mechanism which is an integrated linkage mechanism with the protection mechanism, can realize the impurity removing function while realizing overheat protection without electric drive, and leads the equipment to be more energy-saving, the environmental protection of the equipment is improved.

In light of the foregoing description of the preferred embodiment of the present invention, many modifications and variations will be apparent to those skilled in the art without departing from the spirit and scope of the invention. The technical scope of the present invention is not limited to the content of the specification, and must be determined according to the scope of the claims.