Utility model content
The purpose of this utility model is to provide a kind of satellite time transfer devices, it is intended to solve satellite time transfer in the prior art
The technical issues of temperature of quartz oscillator in device is influenced vulnerable to external air flow and ambient temperature.
A kind of in order to achieve the above purposes, the technical solution adopted by the utility model is: satellite time transfer device, including circuit
Plate, upper cover and quartz oscillator, upper cover are covered on circuit board and enclose with circuit board and set to form installation cavity, circuit board court
It is equipped with the heat dam being located in upper cover orthographic projection to the surface of upper cover, is provided with supporting element, quartz oscillator in heat dam
It is fixed on supporting element and is located in installation cavity, and be formed with heat-insulated air layer between quartz crystal and the slot bottom of heat dam.
Further, heat dam includes the first groove body, and supporting element, which is included in, is separated out the first of the first groove body in heat dam
Partition wall and the second partition wall, quartz oscillator are covered on the first groove body and consolidate with the first partition wall and the second partition wall
Fixed connection, quartz oscillator, the first groove body and circuit board, which enclose to set, is formed with the first heat-insulation chamber.
Further, heat dam further includes the second groove body, and supporting element further includes in being separated out the second groove body in heat dam
Third partition wall and the 4th partition wall, the first groove body have the first end and second end that is oppositely arranged, and the second groove body is set to the
The first end of one groove body simultaneously extends to the other end, the first end phase at the middle part of the second groove body and the first groove body from one end of circuit board
The end of connection, third partition wall towards the first groove body is connected with the end of the first partition wall towards the second groove body, and the 4th separates
The end of wall towards the first groove body is connected with the end of the second partition wall towards the second groove body, upper cover, the second groove body and circuit board
It encloses to set and is formed with the second heat-insulation chamber.
Further, heat dam further includes third groove body, and supporting element further includes in being separated out third groove body in heat dam
5th partition wall and the 6th partition wall, third groove body be set to the second end of the first groove body and have the first end that is oppositely arranged and
Second end;The first end of third groove body is connected with the second end of the first groove body, the end of the 5th partition wall the first groove body of direction
It is connected with the end of the first partition wall towards third groove body, end and second partition wall court of the 6th partition wall towards the first groove body
Be connected to the end of third groove body, the second end of third groove body extends towards the direction away from the first groove body, upper cover, third groove body and
Circuit board, which encloses to set, is formed with third heat-insulation chamber.
Further, heat dam further includes the 4th groove body and the 5th groove body for being respectively arranged at the first groove body two sides, third
Partition wall, the first partition wall and the 5th partition wall are sequentially connected in being separated out the 4th groove body, the 4th partition wall, second in heat dam
Partition wall and the 6th partition wall are sequentially connected in being separated out the 5th groove body in heat dam, and upper cover, the 4th groove body and circuit board are enclosed and set
The 4th heat-insulation chamber is formed, upper cover, the 5th groove body and circuit board enclose and set to form the 5th heat-insulation chamber.
Further, the upper surface of the first partition wall face upper cover and the upper surface of the second partition wall face upper cover are respectively provided with
There is pad, quartz oscillator is fixed with pad solder.
Further, the quantity at least two of pad, and at least described first is respectively arranged at there are two the pad
On partition wall and second partition wall.
Further, satellite time transfer device further includes at least two for being electrically connected quartz oscillator and circuit board
Connecting wire, and the first end of at least two connecting wires respectively it is corresponding at least two pads welding, each connecting wire
Second end respectively along third partition wall, the 4th partition wall, the 5th partition wall or the 6th partition wall be extended.
Further, heat dam be on circuit board use controlled depth milling slot method made of deep groove.
Further, upper cover and welding circuit board, alternatively, upper cover is connect with circuit board by fastener.
The utility model has the beneficial effects that the satellite time transfer device of the utility model, is used to install quartz crystal oscillation
Heat dam is offered on the circuit board of device, supporting element is provided in heat dam, and quartz oscillator is fixed on supporting element simultaneously
It is accommodated in installation cavity, at this point, heat-insulated air layer is capable of forming between quartz oscillator and circuit board, that is,
One layer of heat preservation layer is provided between quartz oscillator and circuit board.In this way, being made by opening up heat dam on circuit boards
Heat-insulated air layer in heat dam replaces circuit board to carry out heat transfer and conduction, since the thermal coefficient of air is less than circuit board
Thermal coefficient, become larger in this way, carrying out the thermal resistance that exchanges of heat between quartz oscillator and external environment, at this point, comparing
In directly carrying out heat transfer by circuit board, heat dam is set and after constructing heat-insulated air layer, quartz oscillator and outer
Heat exchange resistance becomes larger between boundary's environment, and rate of heat exchange reduces, so as to reduce external air flow to quartzy in installation cavity
The influence of the temperature of crystal oscillator, the effective temperature stability for improving quartz oscillator promote quartz crystal oscillation
Device work accuracy.
Specific embodiment
The embodiments of the present invention are described below in detail, examples of the embodiments are shown in the accompanying drawings, wherein from beginning
Same or similar element or element with the same or similar functions are indicated to same or similar label eventually.Below by ginseng
The embodiment for examining the description of attached drawing 1~4 is exemplary, it is intended to for explaining the utility model, and should not be understood as practical to this
Novel limitation.
In the description of the present invention, it should be understood that term " length ", " width ", "upper", "lower", " preceding ",
The orientation or positional relationship of the instructions such as " rear ", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outside" be based on
Orientation or positional relationship shown in the drawings, is merely for convenience of describing the present invention and simplifying the description, rather than instruction or dark
Show that signified device or element must have a particular orientation, be constructed and operated in a specific orientation, therefore should not be understood as pair
The limitation of the utility model.
In addition, term " first ", " second " are used for descriptive purposes only and cannot be understood as indicating or suggesting relative importance
Or implicitly indicate the quantity of indicated technical characteristic.Define " first " as a result, the feature of " second " can be expressed or
Implicitly include one or more of the features.The meaning of " plurality " is two or two in the description of the present invention,
More than, unless otherwise specifically defined.
In the present invention unless specifically defined or limited otherwise, term " installation ", " connected ", " connection ", " Gu
It is fixed " etc. terms shall be understood in a broad sense, for example, it may be being fixedly connected, may be a detachable connection, or integral;It can be
Mechanical connection, is also possible to be electrically connected;It can be directly connected, two can also be can be indirectly connected through an intermediary
The interaction relationship of connection or two elements inside element.It for the ordinary skill in the art, can basis
Concrete condition understands the concrete meaning of above-mentioned term in the present invention.
As shown in figures 1-4, an embodiment of the utility model provides a kind of satellite time transfer device, including circuit board 10,
Upper cover 20 and quartz oscillator 30, wherein circuit board 10 is pcb board, is electrically connected with quartz oscillator 30, and
Be able to carry out the transmitting of electric signal such as clock signal etc. between the two, upper cover 20 in protection circuit plate 10 such as quartz crystal
The electronic component of oscillator 30 etc..Specifically, upper cover 20 is covered on circuit board 10 and encloses with circuit board 10 and sets to form installation sky
Chamber (not shown), circuit board 10 are equipped with the heat dam 11 being located in 20 orthographic projection of upper cover, heat dam 11 towards the surface of upper cover 20
In be provided with supporting element 116, quartz oscillator 30 is fixed on supporting element 116 and is located in installation cavity, and quartz-crystal
Heat-insulated air layer (not shown) is formed between oscillation body device 30 and the slot bottom of heat dam 11.
The satellite time transfer device of the utility model embodiment is used to install the circuit board 10 of quartz oscillator 30
Heat dam 11 is offered, supporting element 116 is provided in heat dam, quartz oscillator 30 is fixed on supporting element 116 and quilt
It is contained in installation cavity, at this point, being capable of forming heat-insulated air layer between quartz oscillator 30 and circuit board 10, i.e., quite
In between quartz oscillator 30 and circuit board 10 be provided with one layer of heat preservation layer.In this way, by opening up on the circuit board 10
Heat dam 11 makes the heat-insulated air layer in heat dam 11 that circuit board 10 be replaced to carry out heat transfer and conduction, due to leading for air
Hot coefficient much smaller than circuit board 10 thermal coefficient (the former thermal coefficient be less than or only the latter's thermal coefficient ten/
One), become larger in this way, carrying out the thermal resistance that heat exchanges between quartz oscillator 30 and external environment, at this point, compared to direct
Heat transfer is carried out by circuit board 10, heat dam 11 is set and after constructing heat-insulated air layer, quartz oscillator 30 and outer
Heat exchange resistance becomes larger between boundary's environment, and rate of heat exchange reduces, so as to reduce external air flow to quartzy in installation cavity
The influence of the temperature of crystal oscillator 30, the effective temperature stability for improving quartz oscillator 30, promotes quartz crystal
The work accuracy of oscillator 30.In this way, by opening up heat dam 11 on the circuit card 1, when the internal clock source of time service device is adopted
When with commonly having source crystal oscillator, heat dam 11, which can be improved, commonly has source crystal oscillator to resist the ability that external air flow and temperature influence, from
And its job stability is improved, and when the internal clock source of time service device is using temperature compensating crystal oscillator, voltage controlled crystal oscillator or constant-temperature crystal oscillator,
Heat dam 11 can then be matched with temperature compensating crystal oscillator or constant-temperature crystal oscillator, further improve its job stability.
Specifically, above-mentioned quartz oscillator 30 is commonly to have source crystal oscillator, temperature compensating crystal oscillator, voltage controlled crystal oscillator or constant temperature
Any one in crystal oscillator, when use, can be selected according to the actual situation, not do unique restriction herein.
Preferably, the size of above-mentioned heat dam 11 can carry out individual Modeling and Design by modeling and simulating software,
In this way, optimizing every design parameter of heat dam 11 by modeling software, the groove body shape and fluting of heat dam 11 are such as adjusted
Depth etc. reduces air heat-insulation layer so as to adjust the heat insulation parameter with the air heat-insulation layer formed inside optimization heat dam 11
Thermal coefficient increases the thermal resistance between quartz oscillator 30 and external environment, improves heat dam 11 and its air heat-insulation layer
To the heat-insulated and heat insulation effect of quartz oscillator 30.
In another embodiment of the utility model, as shown in figs. 2 to 4, heat dam 11 includes the first groove body 111, support
Part 116 is included in the first partition wall 1161 and the second partition wall 1162 that the first groove body 111 is separated out in heat dam 11, quartz-crystal
Oscillation body device 30 is covered on the first groove body 111 and is fixedly connected with the first partition wall 1161 and the second partition wall 1162, quartz
Crystal oscillator 30, the first groove body 111 and circuit board 10, which enclose to set, is formed with the first heat-insulation chamber (not shown).
Specifically, 111 face quartz oscillator 30 of the first groove body is arranged, and quartz oscillator 30 is covered on first
On groove body 111, the bottom margin and the first partition wall 1161 of 30 face circuit board 10 of quartz oscillator and the second partition wall
1162 are fixedly connected with (i.e. the outer edge of 111 notch of the first groove body is fixedly connected), at this point, quartz oscillator 30, the first slot
Body 111 and circuit board 10, which enclose, to be set to form the first heat-insulation chamber, and the first heat-insulation chamber content empties gas to form heat-insulated air layer, in this way,
Quartz oscillator 30 and external air flow along the vertical direction on heat exchange need to be by the heat-insulated air in the first heat-insulation chamber
Layer is conducted, and the lesser heat-insulated air layer of thermal coefficient replaces the biggish circuit board 10 of thermal coefficient to carry out heat conduction, is made
The vertical thermally conductive resistance of quartz oscillator 30 increases, to effectively reduce external air flow to the satellite time transfer device of this implementation
The temperature of interior quartz oscillator 30 influences, and is conducive to the temperature stability and work accuracy of quartz oscillator 30
Raising.
Preferably, the size of the first groove body 111 can carry out individual Modeling and Design by modeling and simulating software, such as
This, by modeling software optimize the first groove body 111 every design parameter, such as adjust the first groove body 111 groove body shape and
Groove depth etc., so as to adjust the sky in the cavity geometry with the first heat-insulation chamber of optimization and size, the first heat-insulation chamber of optimization
The heat insulation parameter of air bound thermosphere, reduce vertical direction on air heat-insulation layer thermal coefficient, increase quartz oscillator 30 with
Thermal resistance between external environment improves the first groove body 111 and its inner air thermal insulation layer to the heat-insulated of quartz oscillator 30
And heat insulation effect.
In another embodiment of the utility model, as shown in figs. 2 to 4, heat dam 11 further includes the second groove body 112, branch
Support member 116 further includes in the third partition wall 1163 and the 4th partition wall 1164 that are separated out the second groove body 112 in heat dam 11
One groove body 111 has the first end and second end being oppositely arranged, and the second groove body 112 is set to the first end of the first groove body 111 simultaneously
The other end is extended to from one end of circuit board 10, the middle part of the second groove body 112 is connected with the first end of the first groove body 111, the
The end of three partition walls 1163 towards the first groove body 111 is connected with the end of the first partition wall 1161 towards the second groove body 112, the
The end of four partition walls 1164 towards the first groove body 111 is connected with the end of the second partition wall 1162 towards the second groove body 112, on
Lid 20, the second groove body 112 and circuit board 10, which enclose to set, is formed with the second heat-insulation chamber (not shown), and the second heat-insulation chamber can accommodate air simultaneously
Heat-insulated air layer is formed, alternatively, the second heat-insulation chamber is connected with the first heat-insulation chamber, heat-insulated air layer is extended into from the first heat-insulation chamber
In second heat-insulation chamber.In this way, the second groove body 112 being connected to by setting with the first groove body 111, by quartz oscillator 30 1
The circuit board 10 at end is arranged to the second heat-insulation chamber to extend for heat-insulated air layer, further to extend covering for heat-insulated air layer
Capping product, increases the thermal resistance of 30 side of quartz oscillator, especially increases quartz oscillator 30 along circuit board 10
Length direction (or width direction) carry out the thermal resistance of hot transmitting, further decrease quartz oscillator 30 by external air flow
And a possibility that generating temperature change, improve the temperature stability of quartz oscillator 30.
It should be noted that the middle part of the second groove body 112 can not also in some other embodiments of the utility model
Be connected with the first groove body 111, i.e., third partition wall 1163 towards the end of the first groove body 111 directly with the 4th partition wall 1164
It is connected towards the end of the first groove body 111, at this point, third groove body 113 and the first setting independently of one another of groove body 111.
Further, as shown in figs. 2 to 4, heat dam 11 further includes third groove body 113, and supporting element 116 further includes in heat-insulated
The 5th partition wall 1165 and the 6th partition wall 1166 of third groove body 113 are separated out in slot 11, third groove body 113 is set to first
The second end of groove body 111 and same there is the first end and second end being oppositely arranged;The first end of third groove body 113 and the first slot
The second end of body 111 is connected, and the 5th partition wall 1165 is towards the end of the first groove body 111 and the first partition wall 1161 towards the
The ends of three groove bodies 113 is connected, and the 6th partition wall 1166 is towards the end of the first groove body 111 and the second partition wall 1162 towards the
The ends of three groove bodies 113 is connected, and the second end of third groove body 113 extends towards the direction away from the first groove body 111, upper cover 20, the
Three groove bodies 113 and circuit board 10, which enclose to set, is formed with third heat-insulation chamber (not shown), third heat-insulation chamber can accommodate air and formed every
Hot air layer, alternatively, third heat-insulation chamber is also connected with the first heat-insulation chamber, heat-insulated air layer can equally extend from the first heat-insulation chamber
To third heat-insulation chamber.The third slot being connected to the first groove body 111 is equally set in the other end of quartz oscillator 30
Body 113 increases in this way, can further extend the area coverage of heat-insulated air layer on the basis of the second groove body 112
The thermal resistance of 30 side of quartz oscillator especially increases the heat that quartz oscillator 30 transversely carries out hot transmitting
Resistance improves quartz-crystal further to reduce a possibility that quartz oscillator 30 is generated temperature change by external air flow
The temperature stability of oscillation body device 30.
It should be noted that in some other embodiments of the utility model, the first end of third groove body 113 can also be with
It is not connected with the second end of the first groove body 111, at this point, third groove body 113 and the first setting independently of one another of groove body 111.
Preferably, the size of above-mentioned second groove body 112 and third groove body 113 again may be by modeling and simulating software
Modeling and Design is carried out in conjunction with the design parameter of the first groove body 111, in this way, optimizing the second groove body 112 and third by modeling software
Every design parameter of groove body 113, so as to adjust the heat-insulated ginseng of the air heat-insulation layer with optimization 30 side of quartz oscillator
Number reduces the thermal coefficient of air heat-insulation layer in horizontal direction, further increases quartz oscillator 30 and external environment
Between thermal resistance, to improve the second groove body 112, third groove body 113 and its inner air thermal insulation layer to quartz oscillator 30
Heat-insulated and heat insulation effect.
Further, as shown in figs. 2 to 4, heat dam 11 further includes be respectively arranged at 111 two sides of the first groove body the 4
Groove body 114 and the 5th groove body 115, third partition wall 1163, the first partition wall 1161 and the 5th partition wall 1165 be sequentially connected in
The 4th groove body 114 is separated out in heat dam 11, the 4th partition wall 1164, the second partition wall 1162 and the 6th partition wall 1166 are successively
Be connected in heat dam 11 and be separated out the 5th groove body 115, upper cover 20, the 4th groove body 114 and circuit board 10 enclose set to be formed the 4th every
Hot chamber (not shown), upper cover 20, the 5th groove body 115 and circuit board, which enclose, to be set to form the 5th heat-insulation chamber (not shown), the 4th heat-insulation chamber
Air can be accommodated with the 5th heat-insulation chamber and forms heat-insulated air layer.In this way, passing through the 4th groove body 114 of setting and the 5th groove body
115, can further expansion air heat-insulation layer area coverage, increase by 30 side of quartz oscillator thermal resistance,
Heat dam 11 and its inner air thermal insulation layer are preferably improved to the insulation effect of quartz oscillator 30.Also, to the 4th
The design parameter of groove body 114 and the 5th groove body 115 again may be by modeling and simulating software in conjunction with the first groove body 111, the second slot
The design parameter of body 112 and third groove body 113 optimizes, to provide optimal thermal resistance value and maximally reduce
Influence of the external air flow to quartz oscillator 30 maintains the temperature stability of quartz oscillator 30.
It should be noted that in some other embodiments of the utility model, the 4th heat-insulation chamber and the 5th heat-insulation chamber
It can be connected respectively at least one of the first heat-insulation chamber, the second heat-insulation chamber or third heat-insulation chamber, at this point, heat-insulated air layer
It is extended into the 4th heat-insulation chamber and the 5th heat-insulation chamber respectively from the first heat-insulation chamber (the second heat-insulation chamber or third heat-insulation chamber).
In another embodiment of the utility model, as shown in Figures 2 and 3, and 1161 face upper cover of the first partition wall
The upper surface of 1162 face upper cover 20 of upper surface and the second partition wall is provided with pad 40, quartz oscillator 30 and pad
40 are welded and fixed, so that quartz oscillator 30 is fixed on circuit board 10.
Preferably, the quantity at least two of pad 40, and at least the first partition wall is respectively arranged at there are two pad 40
1161 and second on partition wall 1162, i.e. a pad 40 is set to the first groove body 111 outside the notch of the 4th groove body 114
Edge, another pad 40 are then set to the first groove body 111 close to the notch outer edge of the 5th groove body 115, in this way, quartz crystal vibrates
The opposite two sides of device 30 respectively pass through a pad 40 and the notch edges of the first groove body 111 are welded, to make quartz crystal
Oscillator 30 is stable to be covered on the first groove body 111, gives full play to air heat-insulation layer to the heat-insulated of quartz oscillator 30
Insulation effect.
It is highly preferred that in the present embodiment, as shown in Fig. 2, the quantity of pad is four, wherein two pads 40 are set to
On first partition wall 1161, in addition two pads 40 are set on the second partition wall 1162, i.e. two settings in four pads 40
In the first groove body 111 close to the notch outer edge of the 4th groove body 114, other two is then set to the first groove body 111 close to the 5th
The notch outer edge of groove body 115, in this way, the bottom four corners of quartz oscillator 30 respectively pass through a pad 40 and the first groove body
111 notch edges welding, preferably to improve the mounting stability of quartz oscillator 30.
In another embodiment of the utility model, as shown in Figures 2 and 3, satellite time transfer device further includes at least two
For being electrically connected the connecting wire 50 of quartz oscillator 30 Yu circuit board 10, and the of at least two connecting wires 50
One end welding corresponding at least two pads 40 respectively, the second end of each connecting wire 50 is respectively along third partition wall 1163, the
Four partition walls 1164, the 5th partition wall 1165 or the 6th partition wall 1166 are extended.
Preferably, above-mentioned connecting wire 50 is the copper conductor that cross-sectional area is relatively small and length is relatively long.Generally
Ground, since the thermal coefficient of copper is relatively large, thermal resistance is relatively small, however, the temperature in order to guarantee quartz oscillator 30
Stability needs to increase as far as possible the thermal resistance of connecting wire 50;Specifically, according to single layer structure thermal resistance formula R=δ/(λ A)
(in formula, R is thermal resistance value (k/w), and δ is the layer thickness (m) of heat-transfer path, and λ is material thermal conductivity [W/ (mk)], and A is
Perpendicular to the material cross-section product (m^2) of heat-transfer path), accordingly as can be seen that reducing the cross-sectional area of connecting wire 50, simultaneously
The length for increasing connecting wire 50, is capable of increasing the thermal resistance of connecting wire 50.Therefore, the present embodiment select cross-sectional area it is smaller,
The longer copper conductor of length increases the thermal resistance of connecting wire 50 with this as connecting wire 50.
Preferably, every design parameter of connecting wire 50 again may be by modeling and simulating software and optimize,
To select optimal length, cross-sectional area and the shape of connecting wire 50 etc., the thermal coefficient of Lai Pingheng connecting wire 50 is posted
The design parameters such as raw inductance, 10 actual fabrication situation of D.C. resistance and circuit board, to provide the thermal resistance of connecting wire 50 most
The figure of merit.
Specifically, the setting quantity of above-mentioned connecting wire 50 is less than or equal to the setting quantity of pad 40 when the two setting
When quantity is identical, a pad 40 is correspondingly connected with a connecting wire 50, i.e., the first end of each connecting wire 50 and each pad 40
Correspond welding;And when the setting quantity of connecting wire 50 be less than pad 40 setting quantity when, not with connecting wire 50
Connected pad 40 is only used for being welded and fixed for quartz oscillator 30.
Preferably, as shown in Fig. 2, the quantity of pad 40 is preferably 4, the quantity correspondence of connecting wire 50 is preferably arranged to
Four, and the first end of four connecting wires 50 corresponds with four pads 40 weld respectively, the of four connecting wires 50
Two ends are set along the extension of third partition wall 1163, the 4th partition wall 1164, the 5th partition wall 1165 or the 6th partition wall 1166 respectively
It sets, so that it is guaranteed that quartz oscillator 30 is stably connected with.
In another embodiment of the utility model, as shown in figs. 2 to 4, heat dam 11 is preferably adopted on circuit board 10
The deep groove made of controlled depth milling slot method.Using controlled depth milling slot technology on circuit board 10 machine-shaping the present embodiment it is heat-insulated
Slot 11, it can be ensured that the machining accuracy of heat dam 11, also, processed using controlled depth milling slot technology, when processing will not destroy
The structural intergrity on the surface away from quartz oscillator 30 of circuit board 10 will not make heat dam 11 through whole circuit board
10, it can be ensured that integrality of the circuit board 10 away from the outer surface of quartz oscillator 30.
Specifically, as shown in Figure 3 and Figure 4, the present embodiment is using controlled depth milling slot processing technology in milling respectively on circuit board 10
The first above-mentioned groove body 111, the second groove body 112, third groove body 113, the 4th groove body 114 and the 5th groove body 115 out, and in circuit
Above-mentioned supporting element 116 is formed on plate 12.
In another embodiment of the utility model, as depicted in figs. 1 and 2, upper cover 20 and circuit board 10 are welded, alternatively,
Upper cover 20 is connect with circuit board 10 by fastener;Setting upper cover 20 is covered on circuit board 10, and by quartz oscillator
30 are mounted on upper cover 20 and circuit board 10 is enclosed and set in the installation cavity to be formed, and to protect quartz oscillator 30, reduce extraneous
Influence of the air-flow to 30 temperature of quartz oscillator.
Preferably, it when upper cover 20 is covered on circuit board 10, is formed between upper cover 20 and quartz oscillator 30
Spacing distance between the lesser gap of height dimension, i.e. upper cover 20 and quartz oscillator 30 is relatively small, with as far as possible
The entire installation cavity of reduction in air especially heat dam 11 in air convection current is carried out by the gap, thus preferably
Guarantee the heat insulation of the heat-insulated air layer of thin layer in heat dam 11.
The above is only the preferred embodiment of the utility model only, is not intended to limit the utility model, all at this
Made any modifications, equivalent replacements, and improvements etc., should be included in the utility model within the spirit and principle of utility model
Protection scope within.