Fastening structure between shells with different expansion coefficients

Abstract

The utility model discloses a fastening structure between shells with different expansion coefficients, which comprises a first shell, a second shell, a main fastening screw and an auxiliary fastening screw which have different expansion coefficients, the first shell is provided with a main positioning column and an auxiliary positioning column which are both provided with screw holes, the second shell is provided with a main positioning hole and an auxiliary positioning hole which are both provided with screw holes, and the main positioning column and the auxiliary positioning column are both provided with screw holes. The main positioning hole is matched with the main positioning column and is fastened through a main fastening screw, and the auxiliary positioning hole is matched with the auxiliary positioning column and is matched through an auxiliary fastening screw; the auxiliary positioning hole is a kidney-shaped hole, and the straight line direction determined by the screw hole center point of the auxiliary positioning column and the screw hole center point of the main positioning column is the same as the length direction of the kidney-shaped hole. According to the fastening structure between the shells with the different thermal expansion coefficients, when the shells made of materials with the different thermal expansion coefficients are connected, the whole structure is not prone to cracking when coping with large temperature differences, and the connecting cost is reduced to a certain degree.

Description

Technical Field

[0001] The utility model relates to the technical field of connecting shells with different expansion coefficients, in particular to a fastening structure between shells with different expansion coefficients. Background Art

[0002] In the prior art, connection through fasteners is one of the commonly used connection methods between shells (or plates). However, when the shells connected to each other are made of materials with different thermal expansion coefficients, such as metal shells and traditional plastic parts, the connection can generally be achieved by adding metal inserts in the plastic material. This connection method not only has high connection costs, but also the overall structure will cause stress concentration in the fastener area of ​​the plastic shell (larger expansion coefficient) due to the difference in material thermal expansion when dealing with a large temperature difference environment, which can easily lead to cracking. Therefore, when shells of materials with different thermal expansion coefficients are connected, the overall structure is not easy to crack when dealing with a large temperature difference, and the connection cost is reduced to a certain extent, which has become a technical problem that needs to be solved in this field. Utility Model Content

[0003] The technical problem to be solved by the utility model is to provide a fastening structure between shells with different expansion coefficients, which can realize that when shells made of materials with different thermal expansion coefficients are connected, the overall structure is not easy to crack when dealing with a large temperature difference, and the connection cost is reduced to a certain extent.

[0004] In order to solve the above technical problems, the utility model provides a fastening structure between shells with different expansion coefficients, including:

[0005] A first housing, which is provided with a main positioning column and an auxiliary positioning column, wherein the main positioning column is located at the middle position of the first housing, and the auxiliary positioning columns are distributed along the circumference of the main positioning column, and screw holes are provided at the central position of the top surface of the main positioning column and the auxiliary positioning column;

[0006] The second housing is provided with a main positioning hole and an auxiliary positioning hole, wherein the main positioning hole cooperates with the main positioning column, and the auxiliary positioning hole cooperates with the auxiliary positioning column; the auxiliary positioning hole is a waist-shaped hole, and the direction of the straight line determined by the center point of the screw hole of the auxiliary positioning column and the center point of the screw hole of the main positioning column is the same as the length direction of the waist-shaped hole;

[0007] A main fastening screw, the screw rod of which passes through the main positioning hole and cooperates with the screw hole of the main positioning column, and the nut of which presses the second housing against the top surface of the main positioning column;

[0008] An auxiliary fastening screw, the screw rod of which passes through the auxiliary positioning hole and cooperates with the screw hole of the auxiliary positioning column, and the nut of which presses the second housing against the top surface of the auxiliary positioning column;

[0009] The thermal expansion coefficients of the first shell and the second shell are not equal.

[0010] Preferably, a main positioning platform is formed by a protrusion at the central position of the top surface of the main positioning column, and a screw hole is provided at the central position of the main positioning platform;

[0011] A central position of the top surface of the auxiliary positioning column is raised to form an auxiliary positioning platform, and a screw hole is provided at the central position of the auxiliary positioning platform.

[0012] Preferably, the outer diameter of the main positioning platform is smaller than the size of the main positioning hole, and the size of the auxiliary positioning platform is smaller than the size of the auxiliary positioning hole.

[0013] Preferably, a crush rib is formed on the side of the second shell facing the first shell, the thickness of the second shell is smaller than the thickness of the main positioning platform, and the sum of the thickness of the second shell and the height of the crush rib is greater than the thickness of the main positioning platform.

[0014] Preferably, the thickness of the second shell is smaller than the thickness of the auxiliary positioning platform, and the sum of the thickness of the second shell and the height of the crushing rib is greater than the thickness of the auxiliary positioning platform.

[0015] Preferably, the dimension of the waist-shaped hole in the length direction is greater than the sum of the relative displacement value and the tolerance value caused by temperature shock.

[0016] Preferably, a gasket is provided at the contact position between the first shell and the second shell.

[0017] Preferably, the gasket is made of silicone or rubber.

[0018] Preferably, the depth of the screw hole formed in the main positioning column is greater than the length of the main fastening screw, and the depth of the screw hole formed in the auxiliary positioning column is greater than the length of the auxiliary fastening screw.

[0019] The utility model realizes the connection of shells made of materials with different thermal expansion coefficients by providing a fastening structure between shells with different expansion coefficients. Since the auxiliary positioning hole is a waist-shaped hole, a distance for the shell with a larger expansion coefficient to move is reserved in the length direction. Therefore, when the overall structure is dealing with a larger temperature difference, the shell with a larger expansion coefficient is centered on the main positioning column (hole), and a stress is generated that expands from the center toward the edge of the shell, or contracts from the edge of the shell toward the center. The stress increases to overcome the friction force generated by the pre-tightening force of the auxiliary fastening screw at the auxiliary positioning column, and movement occurs along the length direction of the waist-shaped hole, so that the stress at the position of the auxiliary fastener is released. The shell with a larger expansion coefficient is not easy to crack, and since there is no need to use metal inserts, the connection cost is reduced to a certain extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solution of the utility model, the following briefly introduces the drawings required for use in the utility model. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 It is an exploded view of an embodiment of the fastening structure of the utility model;

[0022] Figure 2 It is a schematic diagram of an embodiment of a fastening structure of the utility model;

[0023] Figure 3 It is a top view of an embodiment of the fastening structure of the utility model;

[0024] Figure 4 yes Figure 3 The enlarged view of point A in the middle shows the fastening structure of the auxiliary positioning column;

[0025] Figure 5 It is a cross-sectional view of the main positioning column position of an embodiment of the fastening structure of the utility model;

[0026] Figure 6 It is a cross-sectional view of the auxiliary positioning column position of an embodiment of the fastening structure of the utility model;

[0027] Figure 7 This is a schematic diagram of a main positioning column of an embodiment of a fastening structure of the utility model;

[0028] Figure 8 It is a schematic diagram of the main positioning hole of the second shell facing the first shell in one embodiment of the fastening structure of the utility model;

[0029] Fig. 9 This is a cross-sectional view of the auxiliary positioning column where the additional gasket is provided in one embodiment of the fastening structure of the utility model;

[0030] Fig.10 It is a cross-sectional view of the auxiliary positioning column position of an embodiment of the fastening structure of the utility model, wherein the auxiliary fastening screw has a different shape.

[0031] In the figure, 1-first shell; 11-main positioning column; 12-auxiliary positioning column; 111-main positioning platform; 121-auxiliary positioning platform; 2-second shell; 21-main positioning hole; 22-auxiliary positioning hole; 23-compression rib; 3-main fastening screw; 4-auxiliary fastening screw; 5-gasket; 6-screw hole. DETAILED DESCRIPTION

[0032] The following will be combined with the accompanying drawings to clearly and completely describe the technical solutions in the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0033] refer to Figure 1-Figure 10 , shows a fastening structure between shells with different expansion coefficients of the utility model, characterized in that it includes:

[0034] A first housing, which is provided with a main positioning column and an auxiliary positioning column, wherein the main positioning column is located at the middle position of the first housing, and the auxiliary positioning columns are distributed along the circumference of the main positioning column, and screw holes are provided at the central position of the top surface of the main positioning column and the auxiliary positioning column;

[0035] The second housing is provided with a main positioning hole and an auxiliary positioning hole, wherein the main positioning hole cooperates with the main positioning column, and the auxiliary positioning hole cooperates with the auxiliary positioning column; the auxiliary positioning hole is a waist-shaped hole, and the direction of the straight line determined by the center point of the screw hole of the auxiliary positioning column and the center point of the screw hole of the main positioning column is the same as the length direction of the waist-shaped hole;

[0036] A main fastening screw, the screw rod of which passes through the main positioning hole and cooperates with the screw hole of the main positioning column, and the nut of which presses the second housing against the top surface of the main positioning column;

[0037] An auxiliary fastening screw, the screw rod of which passes through the auxiliary positioning hole and cooperates with the screw hole of the auxiliary positioning column, and the nut of which presses the second housing against the top surface of the auxiliary positioning column;

[0038] The thermal expansion coefficients of the first shell and the second shell are not equal.

[0039] In the embodiment of the utility model, the first shell and the second shell are connected by the main fastening screws and the auxiliary fastening screws. The thermal expansion coefficients of the first shell and the second shell are different. When the overall structure is in a large temperature difference environment, the expansion or contraction of the first shell and the second shell are different, and there is a relative movement. Based on this, the auxiliary positioning hole is set as a waist-shaped hole (such as Figure 4), the moving direction is the length direction of the waist-shaped hole, so as to prevent the shell with a larger expansion coefficient from cracking due to stress concentration in the area of ​​the auxiliary fastening screw; in this embodiment, the main positioning column and the main positioning hole are respectively arranged at the middle position of the first shell and the second shell, for example, at the center of gravity or the center position (if the shapes of the first shell and the second shell are regular shapes, they can be arranged at the center position; if they are irregular shapes, they are preferably arranged at the center of gravity). Preferably, the pre-tightening force generated by the fastener here is greater. When the overall structure copes with an environment with a large temperature difference, the shell with a large expansion coefficient (which can be the first shell or the second shell) takes this place as the center, and generates stress that expands from this center to the edge of the shell, or contracts from the edge of the shell to this center. The stress increases to overcome the friction force generated by the pre-tightening force of the auxiliary fastening screw at the auxiliary positioning column, and then moves along the length direction of the waist-shaped hole. It should be noted that there is generally one main positioning column, and there are multiple auxiliary positioning columns, such as four, six or more, which are preferably evenly distributed along the circumference of the main positioning column, (such as Figure 3 ). In addition, the length direction dimension of the waist-shaped hole can be calculated based on the thermal expansion coefficient of the first shell and the second shell and the tolerance superposition of the two, preferably greater than the calculated value, which can be calculated by the existing technology and will not be repeated here. It should also be noted that the solution of this embodiment is applicable to screws of different shapes, such as Fig.10 As shown; preferably, the depth of the screw hole opened in the main positioning column is greater than the length of the main fastening screw, and the depth of the screw hole opened in the auxiliary positioning column is greater than the length of the auxiliary fastening screw; preferably, the nut size of the main fastening screw is greater than the size of the main positioning hole, and the nut size of the auxiliary fastening screw is greater than the width of the auxiliary positioning hole.

[0040] In a specific embodiment, reference Figure 7, the main positioning column is convex at the central position of the top surface to form a main positioning platform, and the screw hole is opened at the central position of the main positioning platform; the auxiliary positioning column is convex at the central position of the top surface to form an auxiliary positioning platform, and the screw hole is opened at the central position of the auxiliary positioning platform. Preferably, the outer diameter of the main positioning platform is smaller than the size of the main positioning hole, and the size of the auxiliary positioning platform is smaller than the size of the auxiliary positioning hole. In this specific embodiment, the shape of the main positioning hole is preferably the same as that of the main positioning platform, and the main positioning hole is sleeved on the main positioning platform. At this time, even if the pre-tightening force at the main positioning column is not greater than the pre-tightening force at the auxiliary positioning column, the limiting effect of the main positioning platform on the main positioning hole can also realize that the shell with a large expansion coefficient can expand toward the edge of the shell with the main positioning column as the center or contract from the edge of the shell to the main positioning column. It should be noted that the outer diameter of the main positioning platform is smaller than the size of the main positioning hole, which means that the main positioning hole can be mounted on the circumference of the main positioning platform. If the main positioning platform is a cylinder and the main positioning hole is a round hole, the diameter of the main positioning hole is smaller than the cylindrical diameter of the main positioning platform. If the main positioning platform is a square column with a square cross-section and the main positioning hole is a square hole, the side length of the main positioning hole is greater than the square side length of the cross-section of the square column, and so on. The size of the auxiliary positioning platform is smaller than the size of the auxiliary positioning hole, which means that the auxiliary positioning hole can be mounted on the circumference of the auxiliary positioning platform, mainly because the width of the waist-shaped auxiliary positioning hole is greater than the size of the auxiliary positioning platform.

[0041] In a specific embodiment, reference Figure 8 A crushing rib is formed on the side of the second shell facing the first shell, the thickness of the second shell is less than the thickness of the main positioning platform, and the sum of the thickness of the second shell and the height of the crushing rib is greater than the thickness of the main positioning platform. The thickness of the second shell is less than the thickness of the auxiliary positioning platform, and the sum of the thickness of the second shell and the height of the crushing rib is greater than the thickness of the auxiliary positioning platform.

[0042] In a specific embodiment, reference Fig. 9 A gasket is provided at the contact position between the first shell and the second shell. Preferably, the gasket is made of silicone or rubber.

[0043] The above description is only a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A fastening structure between shells with different expansion coefficients, characterized in that: include: A first housing, which is provided with a main positioning column and an auxiliary positioning column, wherein the main positioning column is located at the middle position of the first housing, and the auxiliary positioning columns are distributed along the circumference of the main positioning column, and screw holes are provided at the central position of the top surface of the main positioning column and the auxiliary positioning column; The second housing is provided with a main positioning hole and an auxiliary positioning hole, wherein the main positioning hole cooperates with the main positioning column, and the auxiliary positioning hole cooperates with the auxiliary positioning column; the auxiliary positioning hole is a waist-shaped hole, and the direction of the straight line determined by the center point of the screw hole of the auxiliary positioning column and the center point of the screw hole of the main positioning column is the same as the length direction of the waist-shaped hole; A main fastening screw, the screw rod of which passes through the main positioning hole and cooperates with the screw hole of the main positioning column, and the nut of which presses the second housing against the top surface of the main positioning column; An auxiliary fastening screw, the screw rod of which passes through the auxiliary positioning hole and cooperates with the screw hole of the auxiliary positioning column, and the nut of which presses the second housing against the top surface of the auxiliary positioning column; The thermal expansion coefficients of the first shell and the second shell are not equal.

2. The fastening structure according to claim 1, characterized in that: A main positioning platform is formed by a protrusion at the central position of the top surface of the main positioning column, and a screw hole is provided at the central position of the main positioning platform; A central position of the top surface of the auxiliary positioning column is raised to form an auxiliary positioning platform, and a screw hole is provided at the central position of the auxiliary positioning platform.

3. The fastening structure according to claim 2, characterized in that: The outer diameter of the main positioning platform is smaller than the size of the main positioning hole, and the size of the auxiliary positioning platform is smaller than the size of the auxiliary positioning hole.

4. The fastening structure according to claim 2, characterized in that: A crushing rib is formed on a side of the second shell facing the first shell, the thickness of the second shell is smaller than the thickness of the main positioning platform, and the sum of the thickness of the second shell and the height of the crushing rib is greater than the thickness of the main positioning platform.

5. The fastening structure according to claim 4, characterized in that: The thickness of the second shell is smaller than the thickness of the auxiliary positioning platform, and the sum of the thickness of the second shell and the height of the crushing rib is greater than the thickness of the auxiliary positioning platform.

6. The fastening structure according to claim 1, characterized in that: The dimension of the waist-shaped hole in the length direction is greater than the sum of the relative displacement value and the tolerance value caused by the temperature shock.

7. The fastening structure according to claim 1, characterized in that: A gasket is provided at a contact position between the first shell and the second shell.

8. The fastening structure according to claim 7, characterized in that: The material of the gasket is silicone or rubber.

9. The fastening structure according to claim 1, characterized in that: The pre-tightening force at the main positioning column is greater than the pre-tightening force at the auxiliary positioning column.

10. The fastening structure according to claim 1, characterized in that: The depth of the screw hole formed in the main positioning column is greater than the length of the main fastening screw, and the depth of the screw hole formed in the auxiliary positioning column is greater than the length of the auxiliary fastening screw.

Images