Screw fixing structure of heat dissipation unit and its heat dissipation unit

Abstract

The present invention is a screw fixing structure for a heat dissipation unit and the heat dissipation unit. It has a heat receiving area, and through holes are respectively provided at four corners of the periphery of the heat receiving area to penetrate a screw fixing structure. The screw fixing structure is composed of a positioning screw, a hollow sleeve, and a spring fixing member. The positioning screw has a rod body, a nut, and a thread portion. A snap ring accommodating groove is provided above the thread portion to engage a snap ring, and the rod body is sleeved with a spring. The hollow sleeve is sleeved with the rod body of the positioning screw and the spring. One end of the spring abuts against the upper surface of the heat dissipation unit with the lower end of the hollow sleeve. A pair of notches are provided at the upper end of the hollow sleeve. The spring fixing member has a first elastic arm and a second elastic arm corresponding to each other. The first elastic arm and the second elastic arm are connected by a connecting portion, and the first and second elastic arms are respectively clamped and fixed in the notches of the hollow sleeve to stop the spring, so that the spring is in a compressed state.

Description

Technical Field

[0001] The present invention relates to a screw fixing structure, and particularly to a screw fixing structure for a heat dissipation device and a heat dissipation unit thereof, which can provide uniform downward pressure to avoid damage or thermal resistance caused by uneven force on the contact between the bare die computing unit and the radiator. Background Art

[0002] Currently, in order to provide high-performance computing capabilities for electronic devices, high-performance and high-power chips are adopted. When the chips perform operations, a relatively high amount of heat is generated. The external of traditional computing chips has a packaging shell, and the chip is wrapped inside the packaging shell to protect the chip from damage. However, as the computing performance of the chips improves, the chips will generate higher temperatures than traditional ones during operation. Also, since the packaging shell encapsulated outside the chips affects the heat dissipation and heat conduction efficiency of the chips to the outside; thus, most chips on the market have been changed to the form of bare dies. The surface of the bare die is not equipped with a protective packaging shell, and its heat exchange contact surface is small, and the surface is not a flat surface. Without the protection of the outer packaging shell, its strength is relatively low and it is easy to crack when combined with the heat dissipation device. Therefore, when the heat dissipation device is fixed above the heat source (bare die), the locking points are usually located in the directions of the four opposite corners of the heat source. Also, since the contact points at the four corners of the bare die are very small, if the traditional single locking point is locked sequentially, the position of the first locking will be tilted, and the bare die cannot withstand such uneven pressure, which will cause problems such as chip cracking and damage.

[0003] Please refer to Figure 17 、 Figure 18 , which is a schematic diagram of the combination of an existing heat dissipation device and a bare die. Four copper posts B with internal threads are provided at the four corners of the heat source A. Four holes C3 are also provided at the positions of the heat dissipation device C corresponding to the copper posts B, and screw units C1 are respectively inserted through the holes. A spring C2 is sleeved outside the screw units C1. When the heat dissipation device C and the heat source A are locked and combined, it is usually through manual or robotic arm operation of an electric screwdriver to directly perform single-point screwing operations. And in order to speed up the assembly time on the production line and complete it within the limited assembly time, each fixing screw is directly locked in place quickly at one time. When the screw unit C1 is locked to a fixed point, the spring C2 sleeved on the screw unit C1 also abuts against the heat source A at the same time. Then, the defect of uneven force caused by single-point locking immediately occurs. The heat source A (bare die) is hard and brittle. Since the single-point locking of the screw unit C1 and the propping of the spring C2 cannot provide a complete and comprehensive (the four corners of the bare die) uniform downward binding force for the heat source A (bare die), not only can the heat dissipation device not be firmly and flatly arranged above the heat source A (bare die), but also it cannot prevent the bare die from being damaged due to uneven force.

[0004] Furthermore, the bare crystal is quite fragile. As mentioned above, the four corners of the bare crystal must provide a bonding force with uniform downward pressure at the same time. If the four corners of the bare crystal cannot be provided with a downward pressure in an evenly distributed manner, it is easy for the heat sink or heat dissipation device to warp and fail to fully fit or be damaged with the heat source (bare crystal), and it is also easy to form thermal impedance, which will cause uneven heating or heat conduction failure.

[0005] Therefore, how to improve the heat dissipation device to fully and comprehensively provide uniform pressure to tightly fit the heat source and how to provide and maintain appropriate bonding force between the bare die and the heat dissipation device are the primary issues that the industry is currently trying to solve. Summary of the invention

[0006] Therefore, in order to effectively solve the above-mentioned problems, the main purpose of the present invention is to provide a screw fixing structure and a heat dissipation unit having a heat dissipation unit that can simultaneously provide an average downward force, thereby effectively avoiding the effect of cracking or breaking of the corners of the bare die computing unit caused by locking at a single locking point first.

[0007] The present invention provides a screw fixing structure of a heat dissipation unit, characterized in that it comprises:

[0008] A positioning screw has a rod body, the upper and lower ends of the rod body are respectively provided with a nut and a threaded portion, and the rod body is provided with a buckle ring receiving groove adjacent to the threaded portion, and the buckle ring receiving groove is clamped with a buckle ring, and the rod body is sleeved with a spring, the spring has a top end and a bottom end, and the bottom end abuts against the buckle ring;

[0009] A hollow sleeve, having an open upper end, a lower end and an accommodation space between the upper and lower ends and formed in the hollow sleeve, wherein a portion near the upper end is narrowed inwardly to have a neck, the neck is provided with a pair of notches, the pair of notches correspond to each other and radially communicate with the accommodation space, and the hollow sleeve is sleeved with the rod body with the spring inserted therethrough;

[0010] A spring fixing member is clamped in the notch of the hollow sleeve and has a pair of a first elastic support arm and a second elastic support arm corresponding to each other. One end of the first elastic support arm is connected to the second elastic support arm by a connecting portion, and the first elastic support arm and the second elastic support arm are respectively embedded in the accommodating space at the notch to stop the top end of the spring from stretching upward, so that the spring is in a compressed state.

[0011] The screw fixing structure of the heat dissipation unit, wherein: the first elastic support arm and the second elastic support arm respectively have a first end and a second end away from the connecting portion, and the first end and the second end are arranged adjacent to each other but not connected.

[0012] The screw fixing structure of the heat dissipation unit, wherein: a virtual dividing line is provided on the spring fixing member to divide the area surrounded by the first elastic arm, the second elastic arm, the connecting portion, the first end and the second end into a first area and a second area.

[0013] The screw fixing structure of the heat dissipation unit, wherein: the spring fixing member is matched with a pressing fixture, one end of the pressing fixture is provided with a fixing portion and an expanding portion, and the transverse width of the expanding portion is greater than the transverse width of the fixing portion.

[0014] The screw fixing structure of the heat dissipation unit, wherein: the connection positions of the fixing portion and the expanding portion with the pressing fixture have a fixed end and a free end far from the connection position. The transverse width of the fixed end is the widest, and the transverse width of the fixed end decreases towards the free end, so that an acute angle is formed at the free end.

[0015] The screw fixing structure of the heat dissipation unit, wherein: the neck of the hollow sleeve is provided with a first step and a second step. The first step and the second step are located below the pair of notches and can communicate or not communicate with the accommodating space, and the outer diameter of the first step is greater than the outer diameter of the second step to form an inverted step shape. The outer diameter of the hollow sleeve is greater than the outer diameter of the neck.

[0016] The screw fixing structure of the heat dissipation unit, wherein: the pressing fixture is pressed downward towards the lower end of the hollow sleeve, so that its fixing portion is inserted and clamped into the first area of the spring fixing member, and the expanding portion is inserted into the second area of the spring fixing member to expand and separate the first elastic arm and its first end from the second elastic arm and its second end from each other.

[0017] The screw fixing structure of the heat dissipation unit, wherein: since the spring is not pressed by the spring fixing member, its top end is released upward to support and abut against the lower part of the nut of the screw, and the expanded and separated spring fixing member is fixed on the first step or the second step as the pressing fixture moves downward.

[0018] The screw fixing structure of the heat dissipation unit, wherein: the first elastic arm and the second elastic arm of the spring fixing member are respectively provided with an outward convex portion, the outward convex portion is an outward convex arc shape, the outward convex portion can be attached to and conform to the shape of the top end of the spring, and the outward convex portions of the expanded and separated spring fixing member are attached to the first step or the second step of the hollow sleeve through their outward convex arc shapes.

[0019] A heat dissipation unit, characterized in that it includes:

[0020] A radiator is provided with an upper surface, a lower surface, at least four through holes, and a heat receiving area. The at least four through holes penetrate the upper and lower surfaces of the radiator, and a through hole is respectively provided at each of the four corners of the periphery of the heat receiving area.

[0021] A plurality of screw fixing structures, each of the screw fixing structures is respectively provided with a positioning screw, a hollow sleeve, and a spring fixing member. The positioning screw has a rod body, and the upper and lower ends of the rod body respectively have a nut and a thread portion. A snap ring accommodating groove is provided adjacent to the thread portion of the rod body. A spring is sleeved on the rod body. The spring has a top end and a bottom end. The top end abuts against the spring fixing member and the bottom end abuts against the radiator.

[0022] The hollow sleeve has an open upper end, a lower end, and an accommodating space formed between the upper and lower ends and inside the hollow sleeve. A neck is formed by inward narrowing near the upper end. A pair of notches are provided in the neck. The pair of notches correspond to each other and radially communicate with the accommodating space. The hollow sleeve is sleeved with the rod body provided with the spring and is disposed above the at least four through holes of the radiator.

[0023] The spring fixing member is clamped in the notch of the hollow sleeve and has a pair of corresponding first elastic arms and second elastic arms. One ends of the first elastic arm and the second elastic arm are connected by a connecting portion, and the first elastic arm and the second elastic arm are respectively inserted into and clamped in the accommodating space from the notch to block the upward expansion of the top end of the spring, so that the spring is in a compressed state.

[0024] For the heat dissipation unit described above, wherein: after the positioning screw of the screw fixing structure penetrates the through hole of the radiator, a snap ring is clamped in the snap ring accommodating groove of the positioning screw to prevent the screw from separating from the radiator.

[0025] For the heat dissipation unit described above, wherein: the radiator is a heat pipe or a vapor chamber or a combination of a heat pipe and a vapor chamber. The radiator is provided with a heat dissipation fin group in contact with the heat pipe or the vapor chamber or the combination of the heat pipe and the vapor chamber at the same time to improve the heat dissipation efficiency.

[0026] For the heat dissipation unit described above, wherein: the first elastic arm and the second elastic arm respectively have a first end and a second end away from the connecting portion. The first end and the second end are adjacent to each other but not connected.

[0027] For the heat dissipation unit described above, wherein: a virtual dividing line is provided on the spring fixing member to divide the area surrounded by the first elastic arm, the second elastic arm, the connecting portion, the first end, and the second end into a first area and a second area.

[0028] The heat dissipation unit described above, wherein: the spring fixing member of the screw fixing structure cooperates with a press-in jig, and one end of the press-in jig is provided with at least four pairs of fixing portions and expanding portions, and the lateral width of the expanding portion is greater than the lateral width of the at least four fixing portions.

[0029] The heat dissipation unit described above, wherein: the connection positions of the at least four fixing portions and the expanding portion with the press-in jig have a fixed end and a free end far from the connection position. The lateral width of the fixed end is the widest, and the lateral width of the fixed end decreases toward the free end, so that an acute angle is formed at the free end.

[0030] The heat dissipation unit described above, wherein: the neck of the hollow sleeve is provided with a first step and a second step. The first step and the second step are located below the pair of notches and can communicate or not communicate with the accommodating space, and the outer diameter of the first step is greater than the outer diameter of the second step to form an inverted step shape, and the outer diameter of the hollow sleeve is greater than the outer diameter of the neck.

[0031] The heat dissipation unit described above, wherein: the press-in jig is pressed downward toward the lower end of the hollow sleeve, so that its fixing portion is inserted and clamped into the first area of the spring fixing member, and the expanding portion is inserted into the second area of the spring fixing member to expand and separate the first elastic arm and its first end from the second elastic arm and its second end from each other.

[0032] The heat dissipation unit described above, wherein: since the spring is not pressed by the spring fixing member, the top end of the spring is released upward and expands to abut against the lower part of the nut of the screw, and the expanded and separated spring fixing member is fixed on the first step or the second step as the press-in jig moves downward.

[0033] The heat dissipation unit described above, wherein: the first elastic arm and the second elastic arm of the spring fixing member are respectively provided with a convex portion, the convex portion is in an arc shape protruding outward, the convex portion is attached to and conforms to the shape of the top end of the spring, and the convex portion of the expanded and separated spring fixing member is attached to the first step or the second step of the hollow sleeve through its outwardly protruding arc shape.

[0034] The advantages of the present invention are: when the spring fixing member is expanded by an external object, it is forced to remove the stop against the top end of the spring, so that the spring releases its elastic force, and further to provide simultaneous, synchronous and average downward pressure on each through hole of the heat receiving area. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic exploded view of the screw fixing structure of the heat dissipation unit of the present invention.

[0036] Figure 2 It is a schematic external view of the screw fixing structure of the heat dissipation unit of the present invention.

[0037] Figure 3 It is a schematic diagram of the appearance of another angle of the screw fixing structure of the heat dissipation unit of the present invention.

[0038] Figure 4 It is a schematic cross-sectional view of the screw fixing structure of the heat dissipation unit of the present invention.

[0039] Figure 5 It is a schematic diagram before the spring fixing member of the present invention expands.

[0040] Figure 6 It is a schematic diagram during the expansion of the spring fixing member of the present invention.

[0041] Figure 7 、 Figure 8 They are respectively schematic diagrams of the widths of the expansion part and the fixing part of the present invention.

[0042] Figure 9 It is a schematic diagram after the spring fixing member of the present invention expands.

[0043] Figure 10 It is Figure 5 A-A' cross-sectional schematic diagram of

[0044] Figure 11 It is Figure 6 B-B' cross-sectional schematic diagram of

[0045] Figure 12 It is Figure 9 C-C' cross-sectional schematic diagram of

[0046] Figure 13 It is a schematic diagram of the appearance of the heat dissipation unit of the present invention.

[0047] Figure 14 It is a schematic cross-sectional view before the spring fixing member of the heat dissipation unit of the present invention expands.

[0048] Figure 15 It is a schematic cross-sectional view after the spring fixing member of the heat dissipation unit of the present invention expands.

[0049] Figure 16 It is a schematic diagram of another embodiment of the radiator of the heat dissipation unit of the present invention.

[0050] Figure 17 It is a schematic diagram before the combination of the existing heat dissipation device and the bare die.

[0051] Figure 18 It is a schematic diagram after the combination of the existing heat dissipation device and the bare die.

[0052] Description of Reference Numerals: Screw fixing structure 1; positioning screw 11; rod body 111; nut 1111; thread portion 1112; snap ring accommodating groove 1113; snap ring 1114; spring 112; top end 1121; bottom end 1122; hollow sleeve 12; upper end 121; lower end 122; accommodating space 123; neck portion 124; notch 1241; first step 1242; second step 1243; spring fixing member 13; connecting portion 130; first elastic arm 131; first end 1311; convex portion 1312; second elastic arm 132; second end 1321; convex portion 1322; first region 133;; second region 134; pressing jig 2; fixing portion 21; fixed end 211; free end 212; expanding portion 22; fixed end 221; free end 222; radiator 3; through hole 31; heat pipe 32; heat dissipation fin group 33; heated area 34; base 4; coupling hole 41; bare die arithmetic chip 42; heat source A; copper pillar B; heat dissipation device C; screw unit C1; spring C2; hole C3. Detailed Description of the Invention

[0053] The above objects, structures, and functional characteristics of the present invention will be described with reference to the preferred embodiments shown in the accompanying drawings.

[0054] Please refer to Figures 1 - 16 , as shown in the figure, the present invention provides a screw fixing structure 1 for a heat dissipation unit, comprising:

[0055] A positioning screw 11 having a rod body 111, with a nut 1111 and a thread portion 1112 at the upper and lower ends of the rod body 111 respectively. A snap ring accommodating groove 1113 is provided adjacent to the thread portion 1112 of the rod body 111, and a snap ring 1114 is clamped in the snap ring accommodating groove 1113. A spring 112 is sleeved on the rod body 111, enabling the spring 112 to act along the direction of the screw rod 111 of the positioning screw 11 during the process of compression or release, thereby preventing the spring 112 from acting in an unspecified direction during the release process. The spring 112 has a top end 1121 and a bottom end 1122, and the bottom end 1122 abuts against the snap ring 1114;

[0056] In one embodiment, the positioning screw 11 is used to be screwed and fixed to other devices or structures. For example, but not limited to, a coupling portion corresponding to the thread portion 1112 is provided on other devices or structures, and the coupling portion may have internal threads for screwing and fixing the thread portion 1112 of the positioning screw 11, preventing the positioning screw 11 from loosening or displacing and thus being unable to align with the coupling portion to be coupled.

[0057] A hollow sleeve 12 has an open upper end 121, a lower end 122, and a receiving space 123 formed within the hollow sleeve 12 between the upper and lower ends 121, 122. Near the upper end 121, there is a neck 124 that narrows inward. The neck 124 is provided with a pair of notches 1241, a first step 1242, and a second step 1243. The outer diameter of the hollow sleeve 12 is greater than the outer diameter of the neck 124. The outer diameter of the first step 1242 of the neck 124 is greater than the outer diameter of the second step 1243, forming an inverted stepped shape. The pair of notches 1241 correspond to each other and radially communicate with the receiving space 123. The first and second steps 1242, 1243 are located below the pair of notches 1241 and can be in communication or non-communication with the receiving space 123. The hollow sleeve 12 is sleeved outside the rod body 111 of the positioning screw 11 and the spring 112 (i.e., the rod body 111 and the spring 112 are disposed within the receiving space 123 of the hollow sleeve 12).

[0058] The hollow sleeve 12 can prevent the spring 112 from being affected in its function due to foreign objects entering during the process of compression or release.

[0059] A spring fixing member 13 is fastened within the pair of notches 1241 of the aforementioned hollow sleeve 12. The spring fixing member 13 has a pair of first elastic arms 131 and a second elastic arm 132 that are parallel to each other and correspond to each other. One ends of the first elastic arm 131 and the second elastic arm 132 are connected to each other by a connecting portion 130. The other ends of the first elastic arm 131 and the second elastic arm 132 that are away from the connecting portion 130 are provided with a first end 1311 and a second end 1321. The first and second ends 1311, 1321 are adjacent to each other and close to each other but not connected (in contact).

[0060] In addition, a virtual dividing line is provided on the first and second elastic arms 131, 132 of the spring fixing member 13 to divide the area surrounded by the first and second elastic arms 131, 132, the connecting portion 130, the first end 1311, and the second end 1321 into a first area 133 and a second area 134.

[0061] Furthermore, the first and second elastic arms 131, 132 are respectively inserted or snapped into the receiving space 123 from the pair of notches 1241 of the hollow sleeve 12 to block the spring 112 from releasing its upward pushing elastic force upward, so that the spring 112 maintains a compressed state.

[0062] After the spring 112 of this embodiment is placed in the accommodating space 123 of the hollow sleeve 12, since the upper part of the spring 112 in the axial direction is pressed by the first and second elastic arms 131 and 132 of the spring fixing member 13 and cannot push up or stretch, it is in a compressed state. If the first and second elastic arms 131 and 132 of the spring fixing member 113 remove the stop on the top end 1121 of the spring 112, the upper end of the spring 112 will release its elastic force upward and provide an upward pushing force (upward pressure). At the same time, the lower end of the spring 112 also provides a downward supporting force (downward pressure).

[0063] Please refer to Figure 1 、 Figure 5 、 Figure 7 、 Figure 8 wherein the spring fixing member 13 is cooperatively provided with a press-in fixture 2. One end of the press-in fixture 2 is provided with at least one fixing portion 21 and at least one expanding portion 22, and a transverse width H2 of the expanding portion 22 is greater than a transverse width H1 of the fixing portion 21. The connection positions of the fixing portion 21 and the expanding portion 22 with the press-in fixture 2 have a fixed end 211, 221, and a free end 212, 222 away from the connection position. The transverse widths H1, H2 of the fixed end 211, 221 are the widest, and the transverse widths H1, H2 of the fixed end 211, 221 gradually decrease toward the free end 212, 222, so that an acute angle is formed at the free end 212, 222;

[0064] Refer to again Figure 1 、 Figure 5 、 Figure 10 wherein the press-in fixture 2 moves downward toward the lower end 122 of the hollow sleeve 12; Please continue to refer to Figure 1 、 5 、 Figure 11 such that its fixing portion 21 is inserted and clamped in the first region 133 of the spring fixing member 13 and the expanding portion 22 is simultaneously inserted into the second region 134 of the spring fixing member 13, and the press-in fixture 2 continues to move downward toward the lower end 122 of the hollow sleeve 12; so as to expand and separate the first elastic arm 131 and its first end 1311 and the second elastic arm 132 and its second end 1321 in opposite directions to each other, thereby increasing the distance between the first end 1311 and the second end 1321, enabling the spring 112 to be disengaged from the pressing of the spring fixing member 13, making the top end 1121 of the spring 112 release upward and abut against the lower side of the nut 1111 of the positioning screw 11, and the expanded and separated spring fixing member 13 is fixed on the first step 1242 or the second step 1243 along with the downward movement of the press-in fixture 2, as shown in Figure 9 、 Figure 12As shown, the expanded and separated spring fixing member 13 and the hollow sleeve 12 can be selectively removed directly to avoid inconvenience in subsequent installation or processing caused by the expanded spring fixing member 13;

[0065] In some embodiments, the first step 1242 is closer to the pair of notches 1241. During the process of the pressing jig 2 pressing down, the spring fixing member 13 can also be expanded and pressed down and fixed on the first step 1242, thereby reducing the moving stroke when the pressing jig 2 presses down; also, when the pressing jig 2 presses down, the spring fixing member 13 can be fixed on the second step 1243. The height of the second step 1243 is less than the height of the first step 1242 and the hollow sleeve 12, so that fixing the spring fixing member 13 on the second step 1243 can further improve the bonding stability of the spring fixing member 13 and prevent the spring fixing member 13 from coming out from above (the direction of the first step 1242) or below (the junction of the neck 124 and the hollow sleeve 12).

[0066] In some embodiments, an outward convex portion 1312, 1322 may be provided on the first elastic arm 131 or the second elastic arm 132 of the spring fixing member 13. The outward convex portions 1312, 1322 are in an arc shape protruding outward. When the elastic fixing member 13 is arranged at the top end 1121 of the spring 112, the arc shapes of the outward convex portions 1312, 1322 of the elastic fixing member 13 can be attached to and match the shape (arc shape) of the top end 1121 of the spring 112, thereby increasing the contact area between the elastic fixing member 13 and the top end 1121 of the spring 112 and making the elastic fixing member 13 press the spring 112 more firmly with a better effect; when the spring fixing member 13 is expanded and pressed down by the pressing jig 2, the outward convex portions 1312, 1322 of the first and second elastic arms 131, 132 can just fit into the first step 1242 or the second step 1243 of the hollow sleeve 2 through their outward convex arc shapes, so that the combination of the expanded spring fixing member 13 and the hollow sleeve 2 can be more stable and prevent the spring fixing member 13 from bouncing off due to being unable to be fixed during the process of the pressing jig 2 pressing down and expanding.

[0067] Refer to Figure 13 , which is a schematic external view of the heat dissipation unit of the present invention; Figure 14 、 Figure 15 are schematic cross-sectional views of the spring fixing member of the heat dissipation unit of the present invention before and after expansion; As shown, the expansion of the spring fixing member of the heat dissipation unit of the present invention in combination with the screw fixing structure achieves the same force application effect of the present invention. The heat dissipation unit described above includes:

[0068] A radiator 3 is provided with an upper surface, a lower surface, at least four through holes 31 and a heat receiving area 34. The at least four through holes 31 penetrate the upper and lower surfaces of the radiator 3, and a through hole 31 is respectively provided at each of the four corners of the periphery of the heat receiving area 34;

[0069] A plurality of screw fixing structures 1, which are substantially the same as the above. The difference is that the lower end 122 of the hollow sleeve 12 and the bottom end 1122 of the spring 112 abut against the upper surface of the radiator 3 and correspond to the at least four through holes 31;

[0070] In some embodiments, the hollow sleeve 12 and the radiator 3 may be in a separable structural form. Therefore, the lower end 122 of the hollow sleeve 12 abuts against the upper surface of the radiator 3, or the lower end 122 of the hollow sleeve 12 is directly integrated with the upper surface of the radiator 3 to form an integral structural form;

[0071] After the positioning screw 11 of the screw fixing structure 1 penetrates the at least four through holes 31 of the radiator 3, the position of the snap ring accommodating groove 1113 of the positioning screw 11 moves from the upper surface of the radiator 3 to the lower surface, and a snap ring 1114 is clamped in the snap ring accommodating groove 1113 of the positioning screw 11. The screw fixing structures 1 and the radiator 3 are combined through the snap ring 1114, so that the positioning screw 11 of the screw fixing structures 1 and the radiator 3 will not be separated.

[0072] The usage scenario of the heat dissipation unit 3 of the present invention will be explained below. Please refer to the previous figures and descriptions together.

[0073] When the hollow sleeves 12 are placed on the respective through holes 31 of the radiator 3, and the spring 112 is placed in the accommodating space 123 of the hollow sleeve 12 to partially compress the spring 112, the spring fixing member 13 is hoop-mounted in the pair of notches 1241 of the hollow sleeve 12 to stop the spring 112 in the fully compressed state in the accommodating space 123 of the hollow sleeve 12. The positioning screw 11 penetrates the spring fixing member 13, the spring 112, the hollow sleeve 12 and the through hole 31 of the radiator 3, and is clamped on the snap ring accommodating groove 1113 of the positioning screw 11 through the snap ring 1114, so that the spring 112 remains compressed.

[0074] The heat sink 3 is fixedly combined with a base 4. At least four coupling holes 41 and a heat source are provided on the base 4. At the four corners of the periphery of the heat source, a coupling hole 41 is respectively provided and correspondingly aligned with the through holes 31 of the heat sink 3. The heat source is, for example but not limited to, a bare die computing chip 42. The coupling holes 41 are for the threaded portions of the positioning screws 11 of the screw fixing structures 1 to be screwed and combined, so that the heat receiving area 34 of the heat sink 3 is located above the bare die computing unit 42 of the base 4, and the two are in a lightly touching and fitting state. At this time, the heat sink 3 does not exert any pressure on the heat source.

[0075] The operation of the pressing fixture 2 pressing down the screw fixing structures 1 of the heat dissipation unit 3 is substantially the same as described above. The difference is that the pressing fixture 2 has four pairs of the fixing portions 21 and the expanding portions 22 and corresponds to four screw fixing structures 11 (each fixture provides simultaneous and synchronous pressing down). When the spring fixing member 13 expands, the compressed spring 112 will be released and abuts against the bottom of the heat sink 3 and the nut 1111 of the positioning screw 11. Since the threaded portion 1112 of the positioning screw 11 of the screw fixing structure 1 has been screwed and fixed with the coupling hole 41 of the base 4, when one end of the spring 112 of the screw fixing structure 1 abuts against the bottom of the nut 1111 upward, the screw fixing structures 1 cannot be pushed upward and the restricted elastic force of the spring 112 cannot be completely released. Therefore, when the spring 112 is released, the other end will cause the heat sink 3 to abut downward. Through the simultaneous release of the springs 112 of the screw fixing structures 1, the bottom ends 1122 of the springs 112 simultaneously and synchronously provide uniform downward pressure to the four corners of the heat receiving area 34 of the heat sink 3, so that the heat sink 3 and the bare die computing chip 42 of the base 4 are in close contact simultaneously and reach a specific pressure, which can avoid the situation of corner cracking or chipping caused by uneven stress or heat resistance caused by incomplete fitting, and can also avoid the situation of damage to the bare die computing chip 42 caused by excessive downward pressure during the screwing process.

[0076] In some embodiments, the heat sink 3 can be a heat pipe or a vapor chamber or a combination of a heat pipe and a vapor chamber. The upper surface of the heat sink 3 can be further provided with a plurality of heat pipes 32 or at least one heat sink fin group 33 or a combination of the plurality of heat pipes 32 and the heat sink fin group 33. The following description of the combination of the plurality of heat pipes 32 and the heat sink fin group 33 is not intended to limit the implementation of the present case. One end of the plurality of heat pipes 32 can be attached to the upper surface of the heat sink 3. The heat pipes 32 absorb the heat energy of the heat sink 3 by attaching one end to the upper surface of the heat sink 3. The other ends of the heat pipes 32 will penetrate into the heat sink fin groups 33, as Figure 16 shown, to improve the heat dissipation efficiency by increasing the contact area with air.

Claims

1. A screw fixing structure of a heat dissipation unit, characterized in that, It includes: A positioning screw having a rod body with a nut and a thread portion at its upper and lower ends respectively. A snap ring receiving groove is provided adjacent to the thread portion on the rod body, and a snap ring is engaged in the snap ring receiving groove. A spring is sleeved on the rod body. The spring has a top end and a bottom end, and the bottom end abuts against the snap ring; A hollow sleeve having an open upper end, a lower end, and a receiving space formed between the upper and lower ends and within the hollow sleeve. Near the upper end, it is inwardly constricted to have a neck portion. The neck portion is provided with a pair of notches that correspond to each other and radially communicate with the receiving space. The hollow sleeve is sleeved with the rod body through which the spring passes; A spring fixing member is clamped in the notch of the hollow sleeve and has a pair of corresponding first elastic arms and second elastic arms. One ends of the first elastic arm and the second elastic arm are connected by a connecting portion, and the first elastic arm and the second elastic arm are respectively inserted into and clamped in the receiving space from the notch to stop the top end of the spring from expanding upward, making the spring in a compressed state.

2. The screw fixing structure of the heat dissipation unit according to claim 1, characterized in that: The first elastic arm and the second elastic arm have a first end and a second end respectively away from the connecting portion. The first end and the second end are adjacent to each other but not connected.

3. The screw fixing structure of the heat dissipation unit according to claim 2, characterized in that: A virtual dividing line is provided on the spring fixing member to divide the area surrounded by the first elastic arm, the second elastic arm, the connecting portion, the first end, and the second end into a first area and a second area.

4. The screw fixing structure of the heat dissipation unit according to claim 3, wherein: The spring fixing member cooperates with a pressing fixture. One end of the pressing fixture is provided with a fixing portion and an expanding portion, and the transverse width of the expanding portion is greater than the transverse width of the fixing portion.

5. The screw fixing structure of the heat dissipation unit according to claim 4, wherein: The connection position of the fixing portion and the expanding portion with the pressing fixture has a fixed end and a free end away from the connection position. The transverse width of the fixed end is the widest, and the transverse width of the fixed end decreases towards the free end, forming an acute angle at the free end.

6. The screw fixing structure of the heat dissipation unit according to claim 5, wherein: The neck portion of the hollow sleeve is provided with a first step and a second step. The first step and the second step are located below the pair of notches and can be in communication or not in communication with the receiving space. The outer diameter of the first step is greater than the outer diameter of the second step, forming an inverted step shape. The outer diameter of the hollow sleeve is greater than the outer diameter of the neck portion.

7. The screw fixing structure of the heat dissipation unit according to claim 4 or 5, characterized in that: The pressing fixture is pressed downward towards the lower end of the hollow sleeve, so that its fixing portion is inserted and clamped in the first area of the spring fixing member, and the expanding portion is inserted into the second area of the spring fixing member to expand and separate the first elastic arm and its first end from the second elastic arm and its second end from each other.

8. The screw fixing structure of the heat dissipation unit according to claim 6, characterized in that: Since the spring is not suppressed by the spring fixing member, its top end is released upward to expand and abut against the lower side of the nut of the screw, and the expanded and separated spring fixing member is fixed on the first step or the second step as the pressing fixture moves downward.

9. The screw fixing structure of the heat dissipation unit according to claim 6, wherein: The first elastic arm and the second elastic arm of the spring fixing member are respectively provided with an outward convex portion. The outward convex portion is an outwardly convex arc shape, and the outward convex portion can conform to the shape of the top end of the spring. The outward convex portion of the expanded and separated spring fixing member fits into the first step or the second step of the hollow sleeve through its outwardly convex arc shape.

10. A heat dissipation unit, characterized in that, It includes: A radiator is provided with an upper surface, a lower surface, at least four through holes, and a heat-receiving area. The at least four through holes penetrate the upper and lower surfaces of the radiator, and a through hole is respectively provided at each of the four corners of the periphery of the heat-receiving area; A plurality of screw fixing structures, each of the plurality of screw fixing structures is respectively provided with a positioning screw, a hollow sleeve, and a spring fixing member. The positioning screw has a rod body, and a nut and a thread portion are respectively provided at the upper and lower ends of the rod body. A snap ring accommodating groove is provided adjacent to the thread portion of the rod body. A spring is sleeved on the rod body. The spring has a top end and a bottom end. The top end abuts against the spring fixing member and the bottom end abuts against the radiator; The hollow sleeve has an open upper end, a lower end, and an accommodating space formed between the upper and lower ends and inside the hollow sleeve. A neck is formed by inward narrowing near the upper end. A pair of notches are provided on the neck. The pair of notches correspond to each other and radially communicate with the accommodating space. The hollow sleeve is sleeved with the rod body provided with the spring and is disposed above the at least four through holes of the radiator; The spring fixing member is hoop-shaped in the notches of the hollow sleeve and has a pair of corresponding first elastic arms and second elastic arms. One ends of the first elastic arm and the second elastic arm are connected by a connecting portion, and the first elastic arm and the second elastic arm are respectively inserted and clamped into the accommodating space from the notch to block the top end of the spring from expanding upward, so that the spring is in a compressed state.

11. The heat dissipation unit according to claim 10, characterized in that: After the positioning screw of the screw fixing structure penetrates the through hole of the radiator, a snap ring is clamped in the snap ring accommodating groove of the positioning screw to prevent the screw from separating from the radiator.

12. The heat dissipation unit according to claim 10, wherein: The radiator is a heat pipe or a vapor chamber or a hybrid use of a heat pipe and a vapor chamber. The radiator is provided with a heat sink fin group in contact with the heat pipe or the vapor chamber or the hybrid use of the heat pipe and the vapor chamber at the same time to improve the heat dissipation efficiency.

13. The heat dissipation unit according to claim 10, wherein: The first elastic arm and the second elastic arm are respectively provided with a first end and a second end away from the connecting portion. The first end and the second end are adjacent to each other but not connected.

14. The heat dissipation unit according to claim 13, wherein: A virtual dividing line is provided on the spring fixing member to divide the area surrounded by the first elastic arm, the second elastic arm, the connecting portion, the first end, and the second end into a first area and a second area.

15. The heat dissipation unit according to claim 14, wherein: The spring fixing members of the plurality of screw fixing structures cooperate with a pressing fixture. One end of the pressing fixture is provided with at least four pairs of fixing portions and expanding portions. The transverse width of the expanding portions is greater than the transverse width of the at least four fixing portions.

16. The heat dissipation unit according to claim 15, characterized in that: The at least four fixing portions and the expanding portions have a fixed end at the connection position with the pressing fixture and a free end away from the connection position. The transverse width of the fixed end is the widest, and the transverse width of the fixed end decreases toward the free end, so that an acute angle is formed at the free end.

17. The heat dissipation unit according to claim 16, characterized in that: The neck of the hollow sleeve is provided with a first step and a second step. The first step and the second step are located below the pair of notches and can communicate or not communicate with the accommodating space. The outer diameter of the first step is greater than the outer diameter of the second step to form an inverted step shape. The outer diameter of the hollow sleeve is greater than the outer diameter of the neck.

18. The heat dissipation unit according to claim 15 or 16, characterized in that: The pressing fixture presses downward toward the lower end of the hollow sleeve, so that its fixing part is inserted into and clamped in the first area of the spring fixing part, and the expanding part is inserted into the second area of the spring fixing part to expand and separate the first elastic arm and its first end from the second elastic arm and its second end outward from each other.

19. The heat dissipation unit according to claim 17, wherein: Since the spring is not pressed by the spring fixing part, its top end is released upward and expands against the lower part of the nut of the screw, and the spring fixing part that is expanded and separated moves downward with the pressing fixture and is fixed on the first step or the second step.

20. The heat dissipation unit according to claim 17, wherein: The first elastic arm and the second elastic arm of the spring fixing part are respectively provided with a convex part, the convex part is in an arc shape protruding outward, the convex part is attached to and conforms to the shape of the top end of the spring, and the convex part of the spring fixing part that is expanded and separated fits into the first step or the second step of the hollow sleeve through its outwardly protruding arc shape.

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